JP2006221157A - Electrophotographic photoreceptor, image forming apparatus and process cartridge for image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor which suppresses occurrence of background fouling due to leak of charges from an electroconductive substrate, also suppresses charge deterioration in the first round as the adverse effect of the leak, and has high sensitivity, high durability and high stability, an image forming apparatus which uses the photoreceptor, ensures little occurrence of an abnormal image such as background fouling from the first sheet even in repetitive image formation, has high durability and high stability, and allows high-speed output, and a process cartridge for such an image forming apparatus which uses the photoreceptor, has high durability and high stability, allows high-speed output, and ensures easy handling. <P>SOLUTION: The electrophotographic photoreceptor has an undercoat layer containing a metal oxide and a binder resin and a photosensitive layer on the electroconductive substrate, wherein in the undercoat layer containing the metal oxide and the binder resin, at least a copolymer having an amine value of 1-35 mgKOH/g is contained, and in the photosensitive layer, at least a phthalocyanine pigment is contained. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an electrophotographic photosensitive member in which an undercoat layer containing at least a metal oxide and a binder resin and a photosensitive layer are sequentially laminated on a conductive support, and the undercoat layer containing the metal oxide and the binder resin. Is an electrophotographic photoreceptor characterized in that it contains at least a copolymer having an amine value of 1 to 35 mgKOH / g, and the photosensitive layer contains a phthalocyanine pigment, an image forming apparatus using the same, and an image The present invention relates to a process cartridge for a forming apparatus.

  In recent years, the development of information processing systems using electrophotography has been remarkable, and laser printers and digital copiers that record information using light by converting information into digital signals have significantly improved print quality and reliability. . These laser printers and digital copiers that are rapidly spreading are required to have higher speed and smaller size as well as higher image quality. Furthermore, recently, the demand for full-color laser printers and full-color digital copiers capable of full-color printing is rapidly increasing. When full-color printing is performed, it is necessary to superimpose toner images of at least four colors. Therefore, it is particularly important to increase the speed and size of the apparatus.

  In order to realize high speed and downsizing of the apparatus, it is necessary to improve the sensitivity of the electrophotographic photosensitive member used for them and to reduce the diameter of the photosensitive member. In particular, in the case of a tandem system effective for achieving both full color and high speed, since at least four photoreceptors are included in the apparatus, the degree of demand for reducing the diameter of the photoreceptor is very high. However, as the diameter of the photoconductor is reduced, the photoconductor is used in a harsher situation. Therefore, the replacement speed of the conventional photoconductor is greatly increased, especially in a high-speed machine. It becomes a serious problem. Therefore, in order to realize high speed and downsizing of the apparatus, it is indispensable to greatly increase the durability of the photoconductor used at the same time.

  A charge generating material having a high quantum efficiency is indispensable for increasing the sensitivity of the photoreceptor required to cope with an increase in the speed of the image forming apparatus. For organic high-sensitivity photoreceptors, phthalocyanine pigments are widely used as charge generating substances, and in particular, XRD (a diffraction peak (± 0.2 °) at Bragg angle 2θ in CuKα rays (wavelength 1.542 mm) is at least The titanyl phthalocyanine having the maximum diffraction peak at 27.2 ° is very effective, and it is considered that the demand for the titanyl phthalocyanine will further increase as the speed of the image forming apparatus further increases.

  On the other hand, in order to increase the durability of the photoreceptor, it is important to improve the stability of the image quality and particularly to suppress the occurrence of background stains. Background stains are a type of image defect in which countless minute spots are developed in a white background region, and can be said to be a problem that has been manifested in a reversal development type image forming apparatus in which an unexposed portion is a white background. As a mechanism for the occurrence of scumming, when the photosensitive member is charged, a charge having a polarity opposite to that induced on the conductive support side leaks locally and is injected into the photosensitive layer and the surface of the photosensitive member. It is considered that this part is caused by a decrease in charge. In this case, in the initial stage of the photosensitive member, even if the soiling is not obvious, the soiling is likely to become obvious due to fatigue of the photosensitive member due to repeated use or an increase in electric field strength due to wear of the photosensitive layer. It is one of the major factors that determine the life of the body.

In order to realize high durability of the photosensitive member, it is necessary to suppress the background contamination, and for that purpose, it is important to suppress the injection of charges from the conductive support. As these conventional techniques, a technique of providing an undercoat layer or an intermediate layer between a conductive support and a photosensitive layer has been proposed.
For example, Patent Document 1 discloses a cellulose nitrate resin intermediate layer, Patent Document 2 includes a nylon resin intermediate layer, Patent Document 3 includes a maleic acid resin intermediate layer, and Patent Document 4 includes a polyvinyl alcohol resin intermediate layer. Are each disclosed.
However, since these single layers and the intermediate layer of the resin alone have high electric resistance, the residual potential is increased, and in the reversal development method, image density and gradation are lowered. In addition, since these intermediate layers exhibit ionic conductivity due to impurities and the like, the electrical resistance of the intermediate layers is particularly high under low temperature and low humidity, and the environmental dependence of the residual potential is increased. In addition, the electrical resistance of the intermediate layer is lowered under high temperature and high humidity, which may cause a decrease in charging. In order to reduce this, it is necessary to make the intermediate layer thinner, but it was very difficult to achieve compatibility with soiling.

  In order to solve these problems, a method of dispersing a conductive additive in the intermediate layer has been proposed as a technique for controlling the electric resistance of the intermediate layer. For example, Patent Document 5 includes an intermediate layer in which a carbon or chalcogen-based material is dispersed in a curable resin, and Patent Document 6 includes a thermal polymer intermediate layer using an isocyanate-based curing agent to which a quaternary ammonium salt is added, Patent Document 7 discloses a resin intermediate layer to which a resistance modifier is added, and Patent Document 8 discloses a resin intermediate layer to which an organometallic compound is added. However, these resin intermediate layers alone not only greatly reduce the background smudge suppression effect, but also in the image forming apparatus using coherent light such as laser light used in the reversal development method, the light interference fringes appear in the image. It has a problem of appearing so-called moire.

  For the purpose of suppressing the occurrence of moire and simultaneously controlling the electric resistance of the intermediate layer, a photoreceptor containing a filler in the intermediate layer has been proposed. For example, Patent Document 9 includes a resin intermediate layer in which an oxide of aluminum or tin is dispersed, Patent Document 10 includes a resin intermediate layer in which conductive particles are dispersed, and Patent Document 11 includes an intermediate layer in which magnetite is dispersed. In Patent Document 12, a resin intermediate layer in which titanium oxide and tin oxide are dispersed is dispersed. In Patent Documents 13 to 18, borides such as calcium, magnesium, and aluminum, nitrides, fluorides, and oxide powders are dispersed. A resin intermediate layer is disclosed.

  Although the intermediate layer in which the filler is dispersed as described above is effective for suppressing moire, the filler content is higher in order to reduce the residual potential, and the filler is required in order to increase the effect of suppressing scumming. It is preferable that the content is small, and since it is greatly influenced by the resistance of the filler, it is very difficult to achieve both the soiling and the residual potential. Further, the adhesiveness to the conductive support is lowered, and there is a problem that peeling between the support and the intermediate layer is likely to occur, and there are many problems for improving the durability of the photoreceptor.

  In order to solve all such problems, a concept of stacking intermediate layers has been proposed. The structure of lamination is roughly classified into two types. One is a structure in which a resin layer in which a filler is dispersed and a resin layer not containing a filler are sequentially laminated on a conductive support (see FIG. 1 (a)). In the other, a resin layer not containing a filler and a resin layer in which a filler is dispersed are sequentially provided on a conductive support (see FIG. 1B).

Describing the former configuration in detail, in order to conceal defects in the conductive support, a conductive filler dispersion layer in which a low-resistance filler is dispersed is provided on the conductive support, and the resin layer is laminated thereon. Is. These are described in Patent Documents 19 to 27, for example.
On the other hand, as the latter configuration, a resin layer is provided on a conductive support, and a filler dispersion layer in which a low resistance filler or an electron conductive filler is dispersed is provided thereon. These are described in, for example, Patent Documents 28 and 29.
In this way, the lamination of the intermediate layer has a high effect on the suppression of background contamination because charge leakage from the conductive support is suppressed, and at the same time, it is possible to prevent moiré. This is an effective method. As described above, in order to achieve both the effect of suppressing scumming and the effect of preventing moire, the laminated intermediate layer, which is functionally separated, has high durability against scumming, although problems remain in terms of residual potential rise and environmental dependency. Is very effective and useful.

  In these intermediate layers, a method using a polyamide resin is also known, and among them, a method using an intermediate layer containing N-alkoxy (methoxy) methylated nylon is disclosed. For example, Patent Document 30 discloses a method in which an undercoating layer contains an alkoxymethylated copolymer nylon having an alkoxymethylation degree of 5 to 30%, and Patent Document 31 crosslinks an intermediate layer as an inorganic pigment and a binder resin. According to Patent Document 32, the undercoat layer is made of N-alkoxymethylated nylon resin, and the elemental concentration of impurities Na, Ca and P atoms contained in the resin is 10 ppm each. The method described below is a method in which Patent Document 33 includes an N-alkoxymethylated polyamide copolymer containing λ-amino-n-lauric acid as a main component in the intermediate layer. A method of containing a polyamide resin having a unit component having a certain structure is disclosed. By these methods, the effect of suppressing scumming is improved and the influence of residual potential and environment dependency tends to be reduced, and the effect is exhibited particularly when applied to a laminated intermediate layer.

  As described above, the conventional technology described in detail has improved the effect of suppressing scumming and has greatly reduced side effects on residual potential and environmental dependency. By combining these undercoat layer or intermediate layer and the above-mentioned charge generation layer containing titanyl phthalocyanine, it is possible to simultaneously realize high sensitivity and improved stain resistance, and an image forming apparatus using the same This greatly contributes to speeding up, downsizing, and extending the service life. However, the use of a phthalocyanine compound as a charge generating material has been recognized as a problem that the charging voltage in the first round of the photoreceptor decreases and stabilizes from the second round. This problem is a phenomenon that is particularly seen in photoreceptors using phthalocyanine compounds, and is characterized by a marked decrease in charge on the first round of the photoreceptor when left in the dark for several minutes to several tens of minutes after electrostatic fatigue. ing. Further, in the case of the fatigued state after repeated use of the photoconductor, the tendency further increases, and the tendency that the charge decrease amount in the first round also increases as the fatigue time increases is observed. For this reason, when an image is formed in the first round of the photosensitive member, background staining occurs, and the amount of charge decrease increases as the fatigue time increases. Become. Therefore, although it is only the first round of the photoconductor, it has developed into a major problem that affects the life of the photoconductor. This is due to a decrease in charge of the photoconductor, and hole injection from the conductive support is not the direct cause. Therefore, a plurality of undercoat layers or intermediate layers are stacked to inject holes from the conductive support. Even if it is improved, no effect is obtained. In fact, as will be described later, when a plurality of undercoat layers or intermediate layers are laminated, there is a tendency that the amount of charge decrease in the first round is increased despite the improvement in the soil resistance.

  For example, Patent Document 35 discloses a conventional technique related to this first-round charge reduction. For example, Patent Document 35 discloses a method in which a semiconductive material having a band gap of 2.2 eV or more is contained in an undercoat layer. A method of containing a hydroquinone compound or a hindered amine antioxidant in the undercoat layer, Patent Document 38 discloses a method of containing an aluminate in the undercoat layer, and Patent Document 39 discloses a carboxylate and an oxidation compound in the undercoat layer. A method of containing titanium is disclosed. Many approaches from the charge generation layer are also disclosed. For example, Patent Document 40 discloses a method of containing a perylene-based compound as an additive to the charge generation layer, and Patent Document 41 discloses an electron in the charge generation layer. Many methods for containing an attractive compound and an electron-transporting compound have been disclosed (Patent Documents 42 to 54) in which an antioxidant, various complexes, and additives are contained together with other specific phthalocyanines. However, these methods are techniques found in a relatively short life of the photosensitive member, even though the effect on the first-round charge reduction is recognized, the influence on the background stain is not considered. Therefore, the actual situation is that no consideration is given to soiling due to long-term repeated use.

  An object of the present invention is to obtain a photoconductor having high durability and high stability with no increase in background contamination, little deterioration in image quality, even when the photoconductor is repeatedly used over a long period of time. For this purpose, as described above, it is very effective to stack a plurality of undercoat layers or intermediate layers. However, in the present invention, as described above, the first-round charge reduction phenomenon has a tendency to increase with an increase in the repeated use time of the photoconductor, and an undercoat layer effective for suppressing scumming is provided. It became clear that it became more remarkable when at least two layers were laminated. The tendency that the charge reduction amount in the first round increases as the influence of fatigue increases is the same, but when at least two undercoat layers are laminated, the potential drop amount reaches 100 to several hundred volts, and the effect is It was found to extend to the second round of the photoreceptor. Therefore, by laminating the two undercoat layers, the leakage of electric charges from the conductive support is suppressed, and despite this, the durability against scumming has been greatly improved, the printing due to the lowering of the charge in the first round is achieved. The actual situation was that scumming occurred at the start, and high scumming durability was not satisfied. In addition, the first-round charge reduction phenomenon is characteristic when the titanyl phthalocyanine pigment effective for high sensitivity is used in the charge generation layer, even when the undercoat layer has two layers. The high sensitivity and long life of the photosensitive member, that is, both high speed and high durability of the image forming apparatus are hindered by the first round charge reduction. In order to realize a high-sensitivity and long-life photoconductor that suppresses the occurrence of scumming, it is indispensable to suppress the first-cycle charge reduction, and a technology that can suppress them has been eagerly desired.

  In the present invention, as will be described later, by adding a copolymer having an amine value of 1 to 35 mgKOH / g to the undercoat layer containing a metal oxide, the first-round charge reduction is suppressed without any other adverse effects. I found what I could do. The following are mentioned as a prior art regarding these copolymers. Patent Document 55 discloses an example in which a copolymer having an amine value of 1 to 35 mgKOH / g is contained in an intermediate layer as a comparative example. However, the charge generation material used is only an azo pigment, and it is not described at all for the problem of the first-round charge reduction that occurs when a phthalocyanine pigment is used. As can be seen, the object and configuration of the present invention are completely different. Patent Document 56 discloses an example in which an ammonium salt compound of a block copolymer having an acid group is contained in an intermediate layer. This copolymer is described as having an acid value and an amine value of 20 to 200 mg KOH / g. However, no examples using phthalocyanine are described in this copolymer, and the first round unique to the phthalocyanine pigment is described. There is no description on the problem of charge reduction, the purpose is related to the reproduction processing of the electrophotographic photosensitive member, and the object and configuration are completely different from those of the present invention.

  With regard to improving the abrasion resistance of the photoreceptor, it is possible to reduce film thickness fluctuations after repeated use, so it is possible to suppress an increase in electric field strength over time, and to improve soil resistance. It is valid. However, it was clarified that even if the protective layer is provided to suppress the decrease in film thickness over time, the first-cycle charge reduction is not suppressed and the protective layer does not improve. Depending on the protective layer, there is a case where the first-cycle charge decrease amount is increased, and the first-cycle charge decrease is a major problem that hinders the high durability of the photoreceptor. In addition, when a protective layer is provided, the effects of image flow, filming, adhesion of foreign matter, etc. are likely to increase, so it is important to suppress not only the first round charge reduction but also the above-mentioned adverse effects on image quality. is there.

Conventional techniques for improving the abrasion resistance of the photosensitive layer include (i) using a curable binder in the crosslinkable charge transport layer (see, for example, Patent Document 57), and (ii) using a polymer charge transport material. (Iii) a material obtained by dispersing an inorganic filler in a cross-linked charge transport layer (for example, see Patent Literature 59).
As described above, since the fluctuation of the electric field strength with time can be reduced by increasing the wear resistance of the photoreceptor, a high effect can be obtained for the suppression of background contamination. However, among these technologies, those using the curable binder (i) are not compatible with the charge transport material, and the residual potential increases due to impurities such as polymerization initiators and unreacted residues. There is a tendency for image density reduction to occur easily.
In addition, although the polymer type charge transport material (ii) can improve the abrasion resistance to some extent, the durability required for the organic photoreceptor is not fully satisfied. Not reached. In addition, polymer charge transport materials are difficult to polymerize and purify, and it is difficult to obtain high-purity ones, so that electrical characteristics between materials are difficult to stabilize. Furthermore, production problems such as high viscosity of the coating solution may occur.
The dispersion of the inorganic filler (iii) exhibits higher abrasion resistance than a photoreceptor in which a normal low molecular charge transport material is dispersed in an inert polymer, but the charge present on the surface of the inorganic filler. Residual potential increases due to trapping, and image density tends to decrease. In addition, when the unevenness of the inorganic filler and the binder resin on the surface of the photoconductor is large, defective cleaning may occur, which may cause toner filming and image flow.

  Even if these technologies (i), (ii), and (iii) may be effective in suppressing scumming, there are defects in residual potential, cleaning properties, etc., resulting in image defects resulting in durability. I haven't fully satisfied. In addition, if the protective layer or the cross-linked charge transport layer formed on the surface of the photoreceptor has a tendency to decrease in chargeability over time, it may not only affect the background stain but also decrease the first-round charge. This increases the stability of the photoreceptor.

  Furthermore, a photoreceptor containing a polyfunctional acrylate monomer cured product for improving the wear resistance and scratch resistance of (i) is also known (see Patent Document 60). However, in this photoreceptor, although there is a description that the polyfunctional acrylate monomer cured product is contained in the protective layer provided on the photosensitive layer, the protective layer may contain a charge transport material. However, there is a problem of compatibility with the cured product when a cross-linked charge transport layer contains a low-molecular charge transport material. As a result, precipitation of a low-molecular charge transport material and white turbidity occur, and not only the image density is lowered but also the mechanical strength is lowered due to the increase of the exposed portion potential. Furthermore, since this photoconductor specifically reacts with the monomer in a state containing a polymer binder, the three-dimensional network structure does not proceed sufficiently, and the crosslink density becomes dilute, resulting in a dramatic wear resistance. Has not yet been able to demonstrate.

  As a wear resistance technique for a photosensitive layer that replaces these, a charge transport layer formed by using a coating solution comprising a monomer having a carbon-carbon double bond, a charge transport material having a carbon-carbon double bond, and a binder resin. It is known to provide (for example, refer to Patent Document 61). This binder resin is thought to play a role of improving the adhesion between the charge generation layer and the cross-linked charge transport layer, and also relaxing the internal stress of the film during thick film curing, and has a carbon-carbon double bond. These are roughly classified into those having reactivity with the charge transporting substance and those having no reactivity with the double bond.

  This photoconductor is remarkably compatible with wear resistance and good electrical properties, but when a non-reactive binder resin is used, the binder resin, the monomer, and the charge transport material are used. The compatibility with the cured product produced by this reaction is poor, and layer separation occurs in the cross-linked charge transport layer, which may cause scratches and adhesion of external additives and paper powder in the toner.

  In addition, as described above, the three-dimensional network structure does not proceed sufficiently, and the cross-linking density becomes dilute. In addition, what is specifically described as the monomer used in this photoreceptor is a bifunctional one, and in these respects, the abrasion resistance has not yet been satisfied. Even when a binder resin having reactivity is used, although the molecular weight of the cured product is increased, the number of cross-linking bonds between molecules is small, and it is difficult to achieve both the bonding amount and the cross-linking density of the charge transport material. The abrasion resistance was not sufficient.

  A photosensitive layer containing a compound obtained by curing a hole transporting compound having two or more chain polymerizable functional groups in the same molecule is also known (see, for example, Patent Document 62). This photosensitive layer has high hardness because the crosslink density can be increased, but since the bulky hole transporting compound has two or more chain polymerizable functional groups, distortion occurs in the cured product and internal stress increases. In some cases, the crosslinked surface layer is liable to crack or peel off when used for a long period of time. Even in the conventional photoconductors having a cross-linked photosensitive layer in which a charge transporting structure is chemically bonded, it cannot be said that the present invention has sufficient comprehensive characteristics.

  As described above, a number of conventional techniques for improving the wear resistance of a photoconductor have been disclosed. This is effective in suppressing scumming due to the improvement in wear resistance, but on the other hand, the residual potential is likely to increase. Reduced resolution and gradation, image deterioration due to first-round charge, image flow caused by humidity, filming due to difficulty in refacing the photoconductor surface, etc. Since image defects such as flow and adhesion of foreign matter are induced and image quality stability is greatly reduced, the durability of the photoreceptor has not been realized in practice.

  In order to completely suppress the occurrence of scumming, it is necessary to suppress the injection of electric charges from the conductive support, but at the same time, high durability has been realized by not suppressing the influence of the first round charge reduction. It doesn't matter. Laminating the undercoat layer is effective for the suppression of background stains, but on the other hand, there is a side effect that the amount of charge decrease in the first round is significantly increased, thereby increasing the effect of background stains. The fact is. Further, the first-cycle charge reduction is not improved even if the protective layer is formed and the decrease in the film thickness of the photosensitive layer due to repeated use is reduced, and has developed into a major problem that hinders the life of the photoreceptor. In order to achieve higher sensitivity and longer life of the photoconductor, and to increase the speed, size and durability of the image forming device, not only suppresses dirt and improves wear resistance, but also the first round. It became clear that it was also important to suppress the decrease in charging. Furthermore, when the wear resistance is enhanced, it is also important to suppress the occurrence of other image defects such as image flow and filming. In the prior art, it has been possible to achieve high durability of the photoconductor by suppressing the first-cycle charge drop at the same time as the background stain, and further suppressing all image quality deterioration factors such as residual potential rise and image flow or filming. However, there has been a strong demand for both high sensitivity, high durability, and high stability of the photoreceptor.

JP-A-47-6341 JP-A-60-66258 JP 52-10138 A JP 58-105155 A JP 51-65942 A JP 52-82238 A JP-A-55-1130451 JP 58-93062 A JP 58-58556 A Japanese Patent Laid-Open No. 60-111255 JP 59-17557 A JP 60-32054 A JP-A 64-68762 JP-A 64-68763 JP-A 64-73352 JP-A 64-73353 JP-A-1-118848 Japanese Patent Laid-Open No. 1-118849 JP 58-95351 A JP 59-93453 A Japanese Patent Laid-Open No. 4-170552 JP-A-6-208238 JP-A-6-222600 Japanese Patent Laid-Open No. 8-184979 JP-A-9-43886 Japanese Patent Laid-Open No. 9-190005 JP-A-9-288367 Japanese Patent Laid-Open No. 5-80572 JP-A-6-19174 JP-A-9-265202 JP 2002-107984 A Japanese Patent No. 2718044 Japanese Patent No. 3086965 Japanese Patent No. 3226110 JP-A-10-186703 JP 11-258844 A JP-A-11-265084 Japanese Patent Laid-Open No. 11-272001 JP 2000-66432 A Japanese Patent Laid-Open No. 11-084597 JP 2000-039730 A JP 2000-258937 A JP 2000-267314 A JP 2001-033998 A JP 2001-033999 A JP 2001-125292 A JP 2001-154387 A Japanese Patent Laid-Open No. 2002-006518 JP 2002-123010 A JP 2002-251025 A JP 2003-005397 A JP 2003-005398 A JP 2003-005399 A JP 2003-177559 A JP 2003-302773 A JP 2002-278119 A JP 56-48637 A JP-A 64-1728 JP-A-4-281461 Japanese Patent No. 3262488 Japanese Patent No. 3194392 JP 2000-66425 A

An object of the present invention is to suppress the occurrence of background contamination caused by leakage of charges from a conductive support in a photosensitive member containing a phthalocyanine pigment having high sensitivity in a photosensitive layer, and at the same time, it occurs due to a different factor. To provide an electrophotographic photosensitive member having high sensitivity and high durability, capable of suppressing scumming, that is, scumming caused by lowering of charging at the first round, and stably outputting a high-quality image even after repeated use over a long period of time. is there.
Another object of the present invention is to use the above-mentioned photoconductor to reduce the occurrence of abnormal images such as background smudges even when image formation is repeated, and to output high-quality images at high speed at any time, and to output images from print operations. An object of the present invention is to provide an image forming apparatus capable of outputting a high-speed and highly-stable image with a short time until it is applied. Furthermore, another object of the present invention is to provide a process cartridge for an image forming apparatus that uses the above-described photoconductor and can output a high-speed and highly-stable image and has good handling.

  As a result of intensive studies on the above problems, the present inventors have found that in an electrophotographic photoreceptor having an undercoat layer and a photosensitive layer containing a metal oxide and a binder resin on a conductive support, the metal oxide And an undercoat layer containing a binder resin contains at least an copolymer having an amine value of 1 to 35 mgKOH / g, and the photosensitive layer uses an electrophotographic photoreceptor containing at least a phthalocyanine pigment. As a result, the occurrence of scumming due to repeated use over a long period of time is suppressed, and the first-cycle charge reduction is reduced. Thus, a highly sensitive and highly durable electrophotographic photosensitive member is provided, and the present invention has been completed.

That is, the present invention is achieved by the following configurations.
(1) In an electrophotographic photoreceptor in which an undercoat layer containing at least a metal oxide and a binder resin and a photosensitive layer are sequentially laminated on a conductive support, the undercoat layer containing the metal oxide and the binder resin An electrophotographic photosensitive member comprising at least a copolymer having an amine value of 1 to 35 mgKOH / g, wherein the photosensitive layer contains a phthalocyanine pigment.
(2) The electrophotographic photosensitive member according to item (1), wherein the photosensitive layer has a structure in which a charge generation layer and a charge transport layer are sequentially laminated.
(3) A titanyl phthalocyanine having a maximum diffraction peak at least 27.2 ° as a diffraction peak (± 0.2 °) of an X-ray diffraction spectrum of Bragg angle 2θ with respect to CuKα ray (wavelength 1.542Å). The electrophotographic photosensitive member according to item (1) or (2), wherein the electrophotographic photosensitive member is a pigment.
(4) The electrophotographic photosensitive member according to any one of (1) to (3), wherein the copolymer is a modified acrylic block copolymer.
(5) Content of the said copolymer is 0.1-5.0 wt% with respect to a metal oxide, The said (1) thru | or (4) term | claim characterized by the above-mentioned Electrophotographic photoreceptor.
(6) The electrophotographic photosensitive member according to any one of (1) to (5), wherein the metal oxide has a specific resistance of 10 ⁷ Ω · cm or more.
(7) The electrophotographic photosensitive member according to any one of (1) to (6), wherein the metal oxide is titanium oxide.
(8) The metal oxide is a mixture of two or more metal oxides having different average primary particle sizes, and the average primary particle size of the metal oxide having the largest average primary particle size is D1, and the smallest average primary particle When the average primary particle size of the metal oxide having a particle size is D2, the relationship of 0.2 <(D2 / D1) ≦ 0.5 is satisfied. (1) to (7) The electrophotographic photosensitive member according to any one of the items).
(9) The electrophotographic photosensitive member according to item (8), wherein D2 is less than 0.2 μm.
(10) The content ratio of two or more metal oxides having different average primary particle sizes is T1, the content of the metal oxide having the largest average primary particle size, and the metal oxide having the smallest average primary particle size The electron according to item (8) or (9), wherein the weight ratio satisfies a relationship of 0.2 ≦ T2 / (T1 + T2) ≦ 0.8 in terms of weight ratio. Photoconductor.
(11) The electrophotographic photosensitive member according to any one of (1) to (10), wherein the binder resin is a thermosetting resin.
(12) The electrophotographic photosensitive member as described in (11) above, wherein the thermosetting resin comprises an oil-free alkyd resin and a melamine resin.
(13) The electrophotographic photosensitive member as described in (11) above, wherein the thermosetting resin comprises an oil-free alkyd resin and a blocked isocyanate compound.
(14) The electrophotographic photoreceptor as described in (12) or (13) above, wherein the oil-free alkyd resin has a hydroxyl value of 60 or more.
(15) The volume ratio of the metal oxide and the binder resin contained in the undercoat layer containing the metal oxide and the binder resin is in a range of 1/1 to 3/1. The electrophotographic photosensitive member according to any one of (1) to (14).
(16) The electrophotography according to any one of (11) to (15), wherein the undercoat layer containing the metal oxide and the binder resin further contains a catalyst. Photoconductor.
(17) The electrophotographic photoreceptor as described in (16) above, wherein the catalyst is at least one selected from an acid catalyst, an amine catalyst, and a metal compound catalyst.
(18) The electrophotographic photosensitive member according to (16) or (17), wherein the content of the catalyst is 0.01 to 5 wt% with respect to the binder resin.
(19) The thickness of the undercoat layer containing the metal oxide and the binder resin is 1 μm or more and less than 10 μm, according to any one of the items (1) to (18), Electrophotographic photoreceptor.
(20) A structure in which an undercoat layer not containing a metal oxide is provided between the conductive support and the metal oxide and an undercoat layer containing a binder resin, and at least two undercoat layers are laminated. The electrophotographic photosensitive member according to any one of items (1) to (19), wherein
(21) The electrophotographic photosensitive member according to item (20), wherein the undercoat layer not containing the metal oxide contains a polyamide resin.
(22) The electrophotographic photosensitive member as described in (21) above, wherein the polyamide resin is N-methoxymethylated nylon.
(23) The thickness of the undercoat layer not containing the metal oxide is 0.1 μm or more and less than 2.0 μm, according to any one of (20) to (22), The electrophotographic photosensitive member described.
(24) The electrophotographic photosensitive member according to any one of (1) to (23), wherein a protective layer is further formed on the charge transport layer.
(25) The electrophotographic photosensitive member as described in (24) above, wherein the protective layer comprises at least a metal oxide, a charge transport material and a binder resin.
(26) The electrophotographic photosensitive member as described in (25) above, wherein the protective layer further contains a dispersant having an acid value.
(27) The protective layer is a crosslinked charge transport layer obtained by curing a radical polymerizable monomer having no charge transport structure and a radical polymerizable compound having a charge transport structure. The electrophotographic photosensitive member according to item 24).
(28) The crosslinkable charge transport layer is formed by curing a tri- or higher functional radical polymerizable monomer having no charge transport structure and a radical polymerizable compound having a monofunctional charge transport structure. The electrophotographic photosensitive member according to item (27), wherein:
(29) The electrophotographic photosensitive member as described in (27) or (28) above, wherein the crosslinkable charge transport layer is insoluble in an organic solvent.
(30) The functional group of the radically polymerizable trifunctional or higher functional monomer having no charge transporting structure used for the crosslinkable charge transporting layer is an acryloyloxy group and / or a methacryloyloxy group. The electrophotographic photosensitive member according to any one of items (27) to (29).
(31) The ratio of the molecular weight to the number of functional groups (molecular weight / number of functional groups) in a trifunctional or higher functional radical polymerizable monomer having no charge transporting structure used for the crosslinkable charge transport layer is 250 or less. The electrophotographic photosensitive member according to any one of (27) to (30).
(32) The item (27), wherein the functional group of the radically polymerizable compound having a monofunctional charge transporting structure used in the crosslinkable charge transporting layer is an acryloyloxy group or a methacryloyloxy group. To the electrophotographic photoreceptor according to any one of items (31) to (31).
(33) Items (27) to (3), wherein the charge transport structure of the radical polymerizable compound having a monofunctional charge transport structure used in the cross-linked charge transport layer is a triarylamine structure. The electrophotographic photosensitive member according to any one of (32).
(34) The radical polymerizable compound having a monofunctional charge transport structure used in the cross-linked charge transport layer is at least one compound represented by the following general formula (1) or (2). The electrophotographic photosensitive member according to any one of (27) to (33), characterized in that it is characterized in that:

（式中、Ｒ_１は水素原子、ハロゲン原子、置換基を有してもよいアルキル基、置換基を有してもよいアラルキル基、置換基を有してもよいアリール基、シアノ基、ニトロ基、アルコキシ基、−ＣＯＯＲ_７（Ｒ_７は水素原子、置換基を有してもよいアルキル基、置換基を有してもよいアラルキル基又は置換基を有してもよいアリール基）、ハロゲン化カルボニル基若しくはＣＯＮＲ_８Ｒ_９（Ｒ_８及びＲ_９は水素原子、ハロゲン原子、置換基を有してもよいアルキル基、置換基を有してもよいアラルキル基又は置換基を有してもよいアリール基を示し、互いに同一であっても異なっていてもよい）を表わし、Ａｒ_１、Ａｒ_２は置換もしくは無置換のアリーレン基を表わし、同一であっても異なってもよい。Ａｒ_３、Ａｒ_４は置換もしくは無置換のアリール基を表わし、同一であっても異なってもよい。Ｘは単結合、置換もしくは無置換のアルキレン基、置換もしくは無置換のシクロアルキレン基、置換もしくは無置換のアルキレンエーテル基、酸素原子、硫黄原子、ビニレン基を表わす。Ｚは置換もしくは無置換のアルキレン基、置換もしくは無置換のアルキレンエーテル基、アルキレンオキシカルボニル基を表わす。ｍ、ｎは０〜３の整数を表わす。）
（３５）前記架橋型電荷輸送層に用いられる１官能の電荷輸送性構造を有するラジカル重合性化合物が、下記一般式（３）で表される化合物の少なくとも一種以上であることを特徴とする前記第（２７）項乃至第（３４）項のいずれかに記載の電子写真感光体。

(In the formula, R ₁ represents a hydrogen atom, a halogen atom, an alkyl group which may have a substituent, an aralkyl group which may have a substituent, an aryl group which may have a substituent, a cyano group, a nitro group, Group, alkoxy group, —COOR ₇ (R ₇ is a hydrogen atom, an alkyl group which may have a substituent, an aralkyl group which may have a substituent or an aryl group which may have a substituent), halogen Carbonyl group or CONR ₈ R ₉ (R ₈ and R ₉ may have a hydrogen atom, a halogen atom, an alkyl group which may have a substituent, an aralkyl group which may have a substituent, or a substituent. Ar ₁ and Ar ₂ represent a substituted or unsubstituted arylene group, and may be the same or different.Ar ₃ , which may be the same or different from each other. Ar ₄ may be substituted Represents an unsubstituted aryl group, which may be the same or different, X represents a single bond, a substituted or unsubstituted alkylene group, a substituted or unsubstituted cycloalkylene group, a substituted or unsubstituted alkylene ether group, An oxygen atom, a sulfur atom, or a vinylene group, Z represents a substituted or unsubstituted alkylene group, a substituted or unsubstituted alkylene ether group, or an alkyleneoxycarbonyl group, and m and n represent an integer of 0 to 3.)
(35) The radical polymerizable compound having a monofunctional charge transporting structure used in the crosslinkable charge transporting layer is at least one compound represented by the following general formula (3): The electrophotographic photosensitive member according to any one of items (27) to (34).

（式中、ｏ、ｐ、ｑはそれぞれ０又は１の整数、Ｒａは水素原子、メチル基を表わし、Ｒｂ、Ｒｃは水素原子以外の置換基で炭素数１〜６のアルキル基を表わし、複数の場合は異なっても良い。ｓ、ｔは０〜３の整数を表わす。Ｚａは単結合、メチレン基、エチレン基、

(Wherein, o, p and q are each an integer of 0 or 1, Ra represents a hydrogen atom or a methyl group, Rb and Rc represent a substituent other than a hydrogen atom and an alkyl group having 1 to 6 carbon atoms, And s and t each represents an integer of 0 to 3. Za is a single bond, a methylene group, an ethylene group,

を表わす。）
（３６）前記架橋型電荷輸送層に用いられる電荷輸送性構造を有しない３官能以上のラジカル重合性モノマーの成分割合が、架橋型電荷輸送層全量に対し３０〜７０重量％であることを特徴とする前記第（２７）項乃至第（３５）項のいずれかに記載の電子写真感光体。
（３７）前記架橋型電荷輸送層に用いられる１官能の電荷輸送性構造を有するラジカル重合性化合物の成分割合が、架橋型電荷輸送層全量に対し３０〜７０重量％であることを特徴とする前記第（２７）項乃至第（３６）項のいずれかに記載の電子写真感光体。
（３８）前記架橋型電荷輸送層の硬化が加熱又は光エネルギー照射手段によって行なわれたことを特徴とする前記第（２７）項乃至第（３７）項のいずれかに記載の電子写真感光体。
（３９）少なくとも帯電手段、露光手段、現像手段、転写手段、及び電子写真感光体を具備してなる画像形成装置において、該電子写真感光体が前記第（１）項乃至第（３８）項のいずれかに記載の電子写真感光体であることを特徴とする画像形成装置。
（４０）少なくとも帯電手段、露光手段、現像手段、転写手段、及び電子写真感光体からなる画像形成要素を複数配列したことを特徴とする前記第（３９）項に記載の画像形成装置。
（４１）前記画像形成装置に用いられる帯電手段に、スコロトロンが用いられていることを特徴とする前記第（３９）項又は第（４０）項に記載の画像形成装置。
（４２）前記画像形成装置において、画像形成時における感光体の線速が３００ｍｍ／ｓｅｃ以上であることを特徴とする前記第（３９）項乃至第（４１）項のいずれかに記載の画像形成装置。
（４３）前記画像形成装置が、少なくとも電子写真感光体と、帯電手段、露光手段、現像手段、クリーニング手段から選ばれる少なくとも１つの手段とが一体となった画像形成装置用プロセスカートリッジを搭載し、該画像形成装置用プロセスカートリッジが装置本体と着脱自在であることを特徴とする前記第（３９）項乃至第（４２）項のいずれかに記載の画像形成装置。
（４４）少なくとも電子写真感光体を備えた画像形成装置用プロセスカートリッジにおいて、該電子写真感光体が前記第（１）項乃至第（３８）項のいずれかに記載の電子写真感光体であることを特徴とする画像形成装置用プロセスカートリッジ。

Represents. )
(36) The component ratio of the trifunctional or higher functional radical polymerizable monomer having no charge transporting structure used in the crosslinkable charge transport layer is 30 to 70% by weight based on the total amount of the crosslinkable charge transport layer. The electrophotographic photosensitive member according to any one of (27) to (35).
(37) The component ratio of the radical polymerizable compound having a monofunctional charge transporting structure used in the crosslinkable charge transport layer is 30 to 70% by weight based on the total amount of the crosslinkable charge transport layer. The electrophotographic photosensitive member according to any one of (27) to (36).
(38) The electrophotographic photosensitive member according to any one of (27) to (37), wherein the crosslinking type charge transport layer is cured by heating or light energy irradiation means.
(39) In an image forming apparatus comprising at least a charging means, an exposure means, a developing means, a transfer means, and an electrophotographic photosensitive member, the electrophotographic photosensitive member according to the items (1) to (38) An image forming apparatus comprising the electrophotographic photosensitive member according to any one of the above.
(40) The image forming apparatus as described in (39) above, wherein a plurality of image forming elements comprising at least charging means, exposure means, developing means, transfer means, and electrophotographic photosensitive member are arranged.
(41) The image forming apparatus according to item (39) or (40), wherein a scorotron is used as a charging means used in the image forming apparatus.
(42) The image forming apparatus as described in any one of (39) to (41), wherein in the image forming apparatus, the linear velocity of the photosensitive member during image formation is 300 mm / sec or more. apparatus.
(43) The image forming apparatus includes a process cartridge for an image forming apparatus in which at least an electrophotographic photosensitive member and at least one means selected from a charging unit, an exposure unit, a developing unit, and a cleaning unit are integrated. The image forming apparatus according to any one of (39) to (42), wherein the process cartridge for the image forming apparatus is detachable from the apparatus main body.
(44) In a process cartridge for an image forming apparatus including at least an electrophotographic photosensitive member, the electrophotographic photosensitive member is the electrophotographic photosensitive member according to any one of (1) to (38). A process cartridge for an image forming apparatus.

According to the present invention, in an electrophotographic photosensitive member in which an undercoat layer containing at least a metal oxide and a binder resin and a photosensitive layer are sequentially laminated on a conductive support, the undercoat containing the metal oxide and the binder resin is provided. The layer contains at least a copolymer having an amine value of 1 to 35 mgKOH / g, and the photosensitive layer contains a phthalocyanine pigment, so that a conventional phthalocyanine pigment is used as a charge generation material and is repeatedly used for a long time. In this case, it is possible to suppress a decrease in charge corresponding to the first turn of the photoconductor (hereinafter referred to as a first charge reduction), which is noticeable in the case of Dirt has been reduced, achieving both high sensitivity and high image quality.
In addition, by using the photoconductor, a high-quality image with little background contamination can be obtained from the first sheet even when image formation is repeated for a long time, high-speed output is possible, and a high-quality image can be obtained over a long period of time. An image forming apparatus capable of outputting stably is provided. In addition, the realization of high durability and high stability of the photoconductor as described above makes it possible to reduce the size and speed of the image forming apparatus, particularly for tandem type image forming apparatuses and high speed image forming apparatuses. It can be used effectively.

The electrophotographic photosensitive member used in the present invention will be described in detail with reference to the drawings.
FIG. 2A is a cross-sectional view showing a configuration example of the electrophotographic photosensitive member used in the present invention, and an undercoat layer and a photosensitive layer containing a metal oxide and a binder resin are laminated on a conductive support. The configuration is taken.
FIG. 2 (a ′) is a cross-sectional view showing a structural example of the electrophotographic photosensitive member used in the present invention. On the conductive support, an undercoat layer containing a metal oxide and a binder resin, a photosensitive layer, and The protective layer is laminated.
FIG. 2B is a cross-sectional view showing another structural example of the electrophotographic photosensitive member used in the present invention, an undercoat layer containing a metal oxide and a binder resin on a conductive support, charge generation A layer and a charge transport layer are sequentially stacked.
FIG. 2 (b ′) is a cross-sectional view showing another structural example of the electrophotographic photosensitive member used in the present invention. On the conductive support, an undercoat layer containing a metal oxide and a binder resin, charge The generation layer, the charge transport layer, and the protective layer are sequentially stacked.
FIG.2 (c) is sectional drawing which shows another example of a structure of the electrophotographic photoreceptor used for this invention, The undercoat layer which does not contain a metal oxide on a conductive support body, a metal oxide, and a binder It has a structure in which an undercoat layer containing a resin and a photosensitive layer are laminated.
FIG. 2 (c ′) is a cross-sectional view showing another constitutional example of the electrophotographic photosensitive member used in the present invention. On the conductive support, an undercoat layer containing no metal oxide, a metal oxide and It has a configuration in which an undercoat layer containing a binder resin, a photosensitive layer and a protective layer are laminated.
FIG. 2 (d) is a cross-sectional view showing another structural example of the electrophotographic photosensitive member used in the present invention, on the conductive support, an undercoat layer containing no metal oxide, a metal oxide and a binder. It has a configuration in which an undercoat layer containing a resin, a charge generation layer, and a charge transport layer are laminated.
FIG. 2 (d ′) is a cross-sectional view showing another structural example of the electrophotographic photosensitive member used in the present invention. On the conductive support, an undercoat layer containing no metal oxide, a metal oxide, and It has a configuration in which an undercoat layer containing a binder resin, a charge generation layer, a charge transport layer, and a protective layer are laminated.

Examples of the conductive support include those having a volume resistance of 10 ¹⁰ Ω · cm or less, such as metals such as aluminum, nickel, chromium, nichrome, copper, gold, silver, and platinum, tin oxide, and indium oxide. Metal oxide coated with film or cylindrical plastic or paper by vapor deposition or sputtering, or a plate made of aluminum, aluminum alloy, nickel, stainless steel, etc. After the conversion, a tube subjected to surface treatment such as cutting, superfinishing or polishing can be used. Further, endless nickel belts and endless stainless steel belts disclosed in JP-A-52-36016 can also be used as the conductive support.

  In addition, the conductive support dispersed in a suitable binder resin on the support can be used as the conductive support of the present invention. Examples of the conductive powder include carbon black, acetylene black, metal powder such as aluminum, nickel, iron, nichrome, copper, zinc, and silver, or metal oxide powder such as conductive tin oxide and ITO. It is done.

  The binder resin used at the same time is polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer. , Polyvinyl acetate, polyvinylidene chloride, polyarylate resin, phenoxy resin, polycarbonate, cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral, polyvinyl formal, polyvinyl toluene, poly-N-vinyl carbazole, acrylic resin, silicone resin, epoxy resin, Examples thereof include thermoplastic, thermosetting resins, and photocurable resins such as melamine resin, urethane resin, phenol resin, and alkyd resin. Such a conductive layer can be provided by dispersing and coating these conductive powder and binder resin in a suitable solvent such as tetrahydrofuran, dichloromethane, methyl ethyl ketone, and toluene.

  Furthermore, it is electrically conductive by a heat shrinkable tube in which the conductive powder is contained in a material such as polyvinyl chloride, polypropylene, polyester, polystyrene, polyvinylidene chloride, polyethylene, chlorinated rubber, Teflon (registered trademark) on a suitable cylindrical substrate. Those provided with a conductive layer can also be used favorably as the conductive support of the present invention.

Next, the undercoat layer will be described. The undercoat layer in the present invention is classified into at least two types of undercoat layers: an undercoat layer containing no metal oxide and an undercoat layer containing a metal oxide and a binder resin.
The role of the undercoat layer is to suppress the injection of reverse polarity charges induced on the conductive support during charging of the photoconductor, to prevent moire, to conceal defects in the tube, and to adhere the photoconductive layer It has many roles, such as improving sex. In the present invention, the undercoat layer containing the metal oxide and the binder resin further contains a copolymer having an amine value of 1 to 35 mgKOH / g, thereby suppressing the first-round charge reduction of the photoreceptor. It is possible. In addition, moire is prevented by the inclusion of the metal oxide, and the dispersibility of the metal oxide is improved, so that an effect is obtained in suppressing the soiling.
On the other hand, the subbing layer containing no metal oxide is used mainly for the purpose of suppressing the injection of electric charges from the conductive support to the photosensitive layer, thereby greatly improving the stain resistance. In the case of a single undercoat layer, the residual potential tends to increase if an attempt is made to suppress charge injection from the conductive support, and conversely, if the residual potential is reduced, the scumming worsens. As a result of functional separation of such a trade-off relationship by forming a plurality of undercoat layers, the scumming suppression effect can be significantly improved without significantly affecting the residual potential.

  First, the undercoat layer containing the metal oxide and binder resin of the present invention will be described. The subbing layer containing metal oxide and binder resin is mainly for the purpose of preventing moiré, but it has the functions of preventing charge injection from the conductive support (ground fouling), reducing residual potential increase due to fatigue, and reducing dark decay. It also has.

The above-mentioned moire is a kind of image defect in which interference fringes called moire are formed in an image due to optical interference inside the photosensitive layer when writing with coherent light such as laser light. Basically, it is necessary to contain a material having a large refractive index in order to prevent the occurrence of moire by scattering the incident laser light by the undercoat layer. In order to prevent moiré, a configuration in which a metal oxide is dispersed in a binder resin is most effective. As the metal oxide used, a white pigment is effectively used. For example, titanium oxide, calcium fluoride, zinc oxide, calcium oxide, silicon oxide, magnesium oxide, aluminum oxide, barium oxide, calcium oxide, silicon oxide Tin oxide and the like can be mentioned. Among these, relatively conductive metal oxides are effective in reducing the residual potential, but the effect of suppressing soiling is clearly reduced. On the other hand, when a metal oxide having a specific resistance of 10 ⁷ Ω · cm or more is used, the scumming suppression effect is improved, but there is a tendency that the influence of the residual potential is increased. In some cases, it is preferable to adjust the addition ratio in the metal oxide-containing undercoat layer or to use a mixture of a plurality of metal oxides. In the present invention, in enhancing scumming inhibiting effect is preferably Write resistivity than the conductive metal oxide with 10 ⁷ Ω · cm or more metal oxides, specific resistance 10 ⁷ Ω · cm or more, Use a metal oxide having a specific resistance equal to or lower than that of the binder resin, or adjust the specific resistance to be a metal oxide mixture having a specific resistance equal to or higher than 10 ⁷ Ω · cm and lower than the specific resistance of the binder resin. And more preferably used. Among these, titanium oxide is most preferable because it has little influence on the residual potential and has a high moire prevention effect. However, even titanium oxide has conductivity and various surface treatments, and in the present invention, the specific resistance is 10 ⁷ Ω · cm or more, although not limited thereto. It is more preferable to use titanium oxide.
Thus, even if the undercoat layer containing the metal oxide and the binder resin is laminated with the undercoat layer not containing the metal oxide, it is necessary to form a thin film in order to suppress an increase in residual potential. It can be seen that the role of the undercoat layer containing the metal oxide and the binder resin is very large in suppressing charge leakage from the conductive support.

When the specific resistance of the metal oxide used in the present invention is 10 ⁷ Ω · cm or more, a higher effect is exhibited with respect to the suppression of background contamination. The specific resistance was measured using a powder resistance measuring device. Put the metal oxide powder in the cell and put it between the electrodes, apply the load, adjust the amount of the metal oxide powder so that the thickness is about 2 mm, then apply a voltage between the electrodes, and the current flowing at that time Was measured to determine the specific resistance. The contact area of the electrode was about 2.6 cm ² , the load was about 1 kg, and the specific resistance was obtained by reading the current value 60 seconds after voltage application.

The metal oxide used in the present invention preferably has a high purity in order to reduce an increase in residual potential. The purity is preferably 99.0% or more, more preferably 99.4% or more. In particular, impurities contained in titanium oxide are mainly hygroscopic substances such as Na ₂ O and K ₂ O and ionic substances. When the purity of titanium oxide is lower than 99.4%, it depends on the environment. Is unfavorable because of an increase in size. In addition, there is a risk of increased soiling in a high humidity environment. The purity of the metal oxide can be determined by the measurement method shown in JIS K5116.

  The average primary particle size of the metal oxide of the present invention is preferably 0.01 μm to 0.8 μm, and more preferably 0.05 μm to 0.5 μm. However, when only a metal oxide having an average primary particle size of 0.1 μm or less is used, it is effective for reducing background stains, but the moire prevention effect tends to be reduced, while the average primary particle size is reduced. When only a metal oxide larger than 0.4 μm is used, although the moire prevention effect is excellent, there is a tendency that the effect of suppressing soiling is somewhat reduced. In this case, by using a mixture of metal oxides having different average primary particle sizes, there are cases where both reduction of background stains and reduction of moire can be achieved, and there are cases where an effect can also be seen in reducing residual potential. It is valid.

In the present invention, when two or more kinds of metal oxides having different average primary particle sizes are mixed, the average primary particle size of the metal oxide having the largest average primary particle size is D1, and the smallest average primary particle size is When the average primary particle size of the metal oxide is D2, it is preferable to satisfy the relationship of 0.2 <(D2 / D1) ≦ 0.5. As a result, it is possible to achieve both a moire prevention effect and an antifouling effect. In this case, the average primary particle size D2 of the metal oxide having the smallest average primary particle size is preferably less than 0.2 μm. As a result, the background dirt suppressing effect is sufficiently exhibited.
Further, the mixing ratio of two or more kinds of metal oxides having different average primary particle sizes is such that the content of the metal oxide having the largest average primary particle size is T1, and the metal oxide having the smallest average primary particle size When the content of T2 is T2, it is preferable to satisfy the relationship of 0.2 ≦ T2 / (T1 + T2) ≦ 0.8 by weight. If it is smaller than this, the background stain suppressing effect may be reduced, and if it is larger than this, the moire preventing effect may be reduced.

  The copolymer having an amine value of 1 to 35 mgKOH / g used in the present invention has an effect of suppressing the first-round charge reduction and background contamination. Although it is effective if it is contained in the undercoat layer containing the metal oxide and the binder resin, the dispersibility of the metal oxide is improved especially by being adsorbed on the surface of the metal oxide, so A greater effect can be obtained with respect to suppression of eye charge reduction. When the content of the metal oxide contained in the undercoat layer containing the metal oxide and the binder resin is large, it is effective in reducing the increase in residual potential, but the effect of suppressing scumming is reduced and the content is small. Although the effect of suppressing scumming increases, the residual potential tends to increase. It is thought that the scumming-inhibiting effect is reduced when the content of metal oxide is large because the leakage of electric charges from the conductive support is likely to occur, but this is largely due to the aggregation of metal oxide. It is thought that there is. That is, in the portion where the metal oxide is aggregated, the electric charge easily moves, and the portion easily leaks locally from the conductive support, so that the portion tends to be soiled. Further, the agglomerated portion is likely to be defective due to volume shrinkage at the time of curing, which is also considered to affect the soiling. A copolymer having an amine value of 1 to 35 mgKOH / g has an effect of suppressing aggregation of metal oxides, particularly titanium oxide, so that the metal oxide is uniformly dispersed in the undercoat layer. Therefore, it is considered that the effect of suppressing soiling is enhanced by reducing the portion where charges are likely to leak locally.

These copolymers having an amine value of 1 to 35 mg KOH / g include those having a tertiary amine in the structure. In this case, the tertiary amine acts as an adsorbing group and adsorbs on the surface of the metal oxide, particularly titanium oxide, thereby giving steric hindrance between the metal oxides, reducing the contact of the metal oxides and preventing aggregation. it can. This is useful because a high effect can be obtained for improving the dispersibility of the metal oxide. Although the reason why this copolymer having an amine value of 1 to 35 mgKOH / g shows high effectiveness not only for background contamination but also for the first-round charge reduction is not clear, it says that it reduces charge accumulation. It is thought that this is due to the effect of making it difficult to release the accumulated charge. Examples of these specific compounds include commercially available wetting and dispersing agents such as a wetting and dispersing agent manufactured by BYK Chemie, Disperbyk-161, Disperbyk-162, Disperbyk-163, Disperbyk-164. , Disperbyk-166, Disperbyk-167, Disperbyk-168, Disperbyk-168, Disperbyk-182, Disperbyk-2000, Disperbyk-2001, Disperbyk-2050, Disperbyk-2070, etc., or a pigment dispersant manufactured by Enomoto Kasei Co., Ltd. Disparon DA-703-50, Disparon DA-325, Disparon DA-7300, Disparon 1860, Disparon 7004, etc. can be used. Among these, modified acrylic block copolymers are preferred from the viewpoints of dispersibility of metal oxides, side effects on residual potential, scumming suppression effect, and suppression of first-round charge reduction, and Disperbyk-2000 is particularly effective among them. Used.
These wetting and dispersing agents are not dispersants exclusively for inorganic pigments, but are also dispersants that can be used for organic pigments, so that the anchor portion of the dispersing agent covers the entire pigment rather than adsorbing locally to the pigment. It has an effect. By using such a wetting and dispersing agent for the inorganic pigment, it is presumed that the local defects of the pigment dispersion film are greatly reduced, and the effect of suppressing soiling is remarkably increased.

  The amine value of these copolymers in the present invention is 1 to 35 mgKOH / g, preferably 2 to 20 mgKOH / g. When the amine value is larger than this, the increase in residual potential is remarkably increased. When the amine value is zero, the dispersibility of the metal oxide is lowered, and it becomes difficult to obtain the effect of suppressing the background contamination and the first-round charge reduction. The amine value indicates the total amount of 1,2,3 amines, and is defined as the number of mg of caustic potash equivalent to hydrochloric acid required to neutralize 1 g of the sample. The measuring method is based on JIS K 7237. It is. Moreover, as addition amount of the copolymer with an amine value of 1-35 mgKOH / g, 0.1-5.0 wt% is preferable with respect to a metal oxide, and 0.2-2.0 wt% is more preferable. When the addition amount is larger than this, the influence of the increase in the residual potential may be increased, or the metal oxide may be poorly dispersed. On the other hand, when the addition amount is less than this, the dispersibility of the metal oxide is lowered, and the effect of suppressing the background stain and the first round charge reduction cannot be obtained.

As the binder resin used for the undercoat layer containing these metal oxide and binder resin, a known resin can be used. Examples of these binder resins include water-soluble resins such as polyvinyl alcohol, casein, and sodium polyacrylate, alcohol-soluble resins such as polyamide, copolymer nylon, and methoxymethylated nylon, polyurethane, phenol resin, alkyd-melamine resin, Examples thereof include curable resins that form a three-dimensional network structure such as epoxy resins. Among these resins, the curable resin has a very thin charge generation due to the fact that it is cured and the photosensitive layer is coated on the undercoat layer so that it is hardly affected by organic solvents. Since the layer can be stably applied, it is most preferably used.
However, even these curable resins are not preferred if the volume shrinkage during curing is relatively large. If the volume shrinkage at the time of curing is large, cracks may occur in the undercoat layer, the film thickness may become non-uniform, or pigment aggregation may occur, which may promote the occurrence of soiling.
In the present invention, among these thermosetting resins, alkyd-melamine resins are preferably used. When melamine resin is used as a curing agent, there is very little influence due to volume shrinkage during curing. Further, by mixing a copolymer having an amine value of 1 to 35 mgKOH / g, the dispersibility of the pigment is greatly improved, and it becomes possible to remarkably enhance the effect of suppressing scumming. In addition, the lamination with the undercoat layer not containing a metal compound may cause a decrease in the first round charge as a side effect, but the influence of those greatly increases due to the mixing of the copolymer having an amine value of 1 to 35 mgKOH / g. This has made it possible to suppress both background contamination and first-cycle charge reduction at the same time.

In the present invention, a blocked isocyanate compound is also preferably used as a curing agent. A blocked isocyanate compound is an addition reaction product of a di- or polyisocyanate compound and an isocyanate blocking agent. Since the isocyanate group is masked with a blocking agent, the coating solution gels and thickens over time. It becomes possible to suppress. When the blocked isocyanate compound is heated after film formation, the blocking agent is dissociated to expose the isocyanate group and can be cured. In the present invention, a blocked isocyanate compound in which an isocyanate group is masked with a blocking agent is effective and useful as a curing agent in order to maintain the stability of the coating liquid and the coating quality. Examples of blocking agents include phenols such as phenol, cresol and xinol, active methylene compounds such as acetoacetate ester and diethylarate ester, oximes such as ε-caprolactam, acetoxime and cyclohexanone oxime, and tertiary butyl alcohol And tertiary alcohols. Examples of the di- or polyisocyanate compound include isophorone diisocyanate, hexamethylene diisocyanate, toluylene diisocyanate, xylylene diisocyanate, diphenylmethane diisocyanate, polyphenylmethane polyisocyanate, and the like. Specific examples of the blocked isocyanate compound include IPUL-B1065 and IPDI-B1530 manufactured by HULS, which are isophorone diisocyanates using ε-caprolactam as a blocking agent, and IPDI manufactured by HULS which is an internally blocked uretdione-bonded blocked isophorone diisocyanate. -BF1540. Further, there may be mentioned those obtained by blocking 2,4-toluylene diisocyanate, 2,6-toluylene diisocyanate, diphenylmethane-4,4-diisocyanate, hexamethylene diisocyanate and the like with oxime. Examples of oximes include formaldehyde oxime, acetoald oxime, methyl ethyl ketoxime, cyclohexanone oxime, etc. Examples of blocked isocyanates blocked with oxime include DM-60, DM-160 manufactured by Meisei Chemical Industry Co., Ltd., Dainippon Ink Corp. Burnock B7-887-60, B3-867, DB980K may be mentioned.

  Of course, the use of a blocked isocyanate compound as a curing agent is effective in suppressing the solvent resistance and the generation of formaldehyde, but other effects of containing a blocked isocyanate compound include the dispersibility of metal oxides. It was confirmed that it is effective for further improvement. In the subbing layer containing the metal oxide and the binder resin, it is considered that the portion where the metal oxide is aggregated is liable to cause leakage of electric charges from the conductive support and easily cause scumming. By suppressing aggregation of metal oxide and increasing dispersibility, it becomes possible to suppress charge leakage, and further dispersibility can be improved by mixing with a copolymer having an amine value of 1 to 35 mgKOH / g. As a result, it has become possible to further enhance the effect of suppressing soiling. Further, when a blocked isocyanate compound is used as a curing agent, a reduction in residual potential is realized, and this effect is rather greater than when a melamine resin is used as the curing agent. On the other hand, there is a tendency that the influence of the melamine resin is slightly larger than that in the case of using the melamine resin for the first round charge reduction. In addition to the suppression and the increase in the residual potential, the first-cycle charge decrease can be sufficiently suppressed. In this way, in the undercoat layer containing the metal oxide and the binder resin, the block oxide compound is contained as a curing agent and further mixed with a copolymer having an amine value of 1 to 35 mgKOH / g. It is possible to improve the dispersibility of the material, to suppress both the background contamination and the residual potential, and to further reduce the influence of the first charge reduction, and by the combined effect of the undercoat layer that does not contain a metal oxide. As a result, dramatic improvement in durability of the photoconductor is realized. In addition, the improved dispersibility of the metal oxide improves the life of the dispersion and also improves the coating stability, making it highly stable both in the production of the photoreceptor and in terms of the quality of the photoreceptor. Is realized.

  On the other hand, as the main agent, it is particularly preferable to use an alkyd resin among commercially available general-purpose resins. The alkyd resin has little effect on the residual potential and is effective for suppressing soil contamination. In particular, an alkyd-melamine or alkyd-blocked isocyanate thermosetting resin has a strong tendency, and the dispersibility of the metal oxide is preferably maintained.

  The hydroxyl value of the main agent is preferably 60 or more. When the hydroxyl value is less than 60, since there are few reaction points with the curing agent, sufficient curing is not performed, which may cause deterioration of film forming property, decrease in adhesion, increase in residual potential, and the like. On the other hand, if the hydroxyl value exceeds 150, unreacted functional groups remain, thereby deteriorating moisture resistance, which may cause a significant increase in residual potential and sensitivity deterioration in a high humidity environment. The hydroxyl value is determined by the method defined in JIS K 0070.

  The alkyd resin is a saturated polyester resin composed of a polybasic acid and a polyhydric alcohol, and has a straight-chain structure connected by an ester bond that does not contain a fatty acid. Preferable specific examples of the oil-free alkyd resin used in the present invention include Beccolite M-6401-50, M-6402-50, M-6003-60, M-6605-60, 46-118, 46-119. , 52-584, M-6154-50, M-6301-45, 55-530, 54-707, 46-169-S, M-6201-40-1M, M-6205-50, 54-409 (large Nippon Ink Chemical Co., Ltd .: trade name of oil-free alkyd resin), Espel 103, 110, 124, 135 (trade name of oil-free alkyd resin manufactured by Hitachi Chemical Co., Ltd.) and the like.

Moreover, in the undercoat layer containing the metal oxide and the binder resin in the present invention, it is effective and useful to add a curing catalyst when the thermosetting resin is used as the binder resin. When no catalyst is added, the curing reaction may be insufficient, and in order to suppress it, it is necessary to increase the curing temperature. If the curing reaction is not sufficient, the number of unreacted residues will increase, causing an increase in residual potential and sensitivity deterioration, decreasing the adhesion of the undercoat layer, and forming the components contained in the undercoat layer on it. May be dissolved in the photosensitive layer, which greatly affects the electrostatic characteristics and image quality. By adding a catalyst, it is possible to suppress these effects, and it is possible to reduce the curing temperature and the curing time.
Further, when the degree of curing of the film is increased by adding a curing catalyst, the residual potential tends to be significantly reduced, which is effective. However, when a curing catalyst was added to the undercoat layer, there was a tendency that the residual potential was reduced while the soiling was slightly worsened as a side effect and the effect of lowering the first round charge was slightly increased. However, in the present invention, the undercoating layer containing the metal oxide and the binder resin contains a copolymer having an amine value of 1 to 35 mgKOH / g, thereby improving background staining and first-round charge reduction. In addition, it is a very effective and useful method because it does not pose a problem because it is possible to further suppress soiling by laminating an undercoat layer that does not contain a metal oxide.
As the curing catalyst, known materials that are generally used can be used, and among them, it is preferable to select an acid catalyst, an amine catalyst, and a metal compound catalyst. Thereby, the stability of the film quality and the coating solution is maintained without impairing the effect of adding the copolymer having an amine value of 1 to 35 mgKOH / g, and the residual potential and image quality are not greatly affected. In the present invention, it is preferable to use an acid catalyst when a melamine resin is used as a curing agent, and an amine catalyst or a metal compound catalyst when a blocked isocyanate compound is used.
As an acid catalyst to be added when a melamine resin is used as a curing agent, known materials can be used. For example, organic acids such as maleic acid, citric acid, tartaric acid, succinic acid, sulfonic acid, Inorganic acids such as boric acid and hypophosphorous acid can be used. In particular, organic acids are preferable, and among them, the use of sulfonic acid and its derivatives makes it possible to suppress the amount of catalyst added, which is preferable in terms of electrostatic characteristics. Examples of sulfonic acids include benzenesulfonic acid, paratoluenesulfonic acid, 2-naphthalenesulfonic acid, dodecylbenzenesulfonic acid, dinonylnaphthalenesulfonic acid, dinonylnaphthalenedisulfonic acid, camphorsulfonic acid, anthraquinone 1,5-disulfonic acid , Anthraquinone 2,6-disulfonic acid, anthraquinone disulfonic acid, and the like that have a sulfonic acid group directly bonded to an aromatic group, and those that have a sulfonic acid group directly bonded to an alicyclic compound. In addition, derivatives such as sulfonic acid ester, sulfonic acid amide, and sulfonic acid halide may be used.
On the other hand, a known material can be used as an amine catalyst added when a blocked isocyanate compound is used as a curing agent, for example, N-methylmorpholine, triethylamine, N, N′-dimethylbenzyl. Amine, N, N′-dimethylpiperazine, triethylenediamine, N-ethylmorpholine, N, N, N ′, N-tetramethylethylenediamine, N, N, N ′, N′-tetramethyl-1,3-butanediamine , N-hexamethyltriethylenetetramine and the like. Examples of the metal compound catalyst include stannous oxide, dibutyltin dilaurate, dibutyltin diacetate, zinc naphthenate, antimony trichloride, potassium oleate, sodium O-phenylphenate, sodium lead nitrate, and ferric chloride. , Tetra-n-butyltin, tetra (2-ethylhexyl) titanate, cobalt 2-ethylhexoate, ferric 2-ethylhexoate iron and the like.
The addition amount of these curing catalysts is preferably 0.01 to 10% by weight and more preferably 0.1 to 3% by weight with respect to the amount of the binder resin. If the addition amount is too small, the effect as a curing catalyst cannot be obtained, and if the addition amount is too large, there are side effects such as an increase in residual potential, a decrease in charge, occurrence of scumming, and an increase in the decrease in the first round charge depending on the type of catalyst. There is a risk of growing.
In addition, the ratio of the main agent and the curing agent greatly affects the degree of curing. If the ratio between the main agent and the curing agent is not appropriate, it is conceivable that the residual potential rises remarkably, or the volume shrinkage due to thermal curing increases, and coating film defects such as cracks occur. In particular, coating film defects in these undercoat layers cause charge leakage and directly lead to an increase in soiling, so that the coating film quality needs to be kept good. In the present invention, in the thermosetting resin used as the resin for the undercoat layer containing the metal oxide and the binder resin, the content ratio of the main agent and the curing agent is in the range of 1/1 to 4/1 by weight ratio. The same applies to alkyd-melamine and alkyd-blocked isocyanate. Thereby, there is no occurrence of coating film defects, and the influence of the increase in residual potential can be reduced.

The content ratio of the metal oxide and the binder resin also affects background contamination, residual potential, and first-cycle charge reduction. When the content ratio of the metal oxide with respect to the binder resin increases, the residual potential decreases and the first-cycle charge reduction amount tends to decrease, but the background contamination tends to increase. On the other hand, when the content ratio is low, it is effective for suppressing scumming, but there is a tendency that the residual potential and first-cycle charge decrease increase. In the present invention, the volume ratio between the metal oxide and the binder resin is preferably in the range of 1/1 to 3/1. When the volume ratio of the two is less than 1/1, not only the moire prevention ability is lowered, but also there is a possibility that the residual potential increase and the first-cycle charge reduction amount in repeated use are remarkably increased. On the other hand, in the region where the volume ratio is 3/1 or more, not only the binding ability of the binder resin is lowered, but also the coating film surface property is deteriorated and the film forming property of the upper layer may be adversely affected. In addition, there is a risk that the effect of suppressing soiling is greatly reduced. In the present invention, by containing a copolymer having an amine value of 1 to 35 mgKOH / g in the undercoat layer containing a metal oxide and a binder resin, the residual potential increase and It is possible to reduce the influence of the decrease in charge, which is very effective in achieving both.

  The thickness of the undercoat layer containing the metal oxide and the binder resin needs to be adjusted depending on the thickness of the undercoat layer not containing the metal oxide, but when titanium oxide is used as the metal oxide, In order to achieve both the contamination and the residual potential, 1 to 10 μm, preferably 2 to 5 μm is appropriate. If the film thickness is less than 1 μm, the moire prevention effect may decrease or the charge reduction due to fatigue may increase. If the film thickness is more than necessary, the residual potential may increase. In the present invention, the undercoat layer containing the metal oxide and the binder resin is preferably thicker than the undercoat layer not containing the metal oxide. As a result, it is possible to suppress a decrease in electrification due to fatigue, and it is effective in suppressing scumming.

  A coating liquid can be obtained by dispersing the metal oxide together with a solvent and a binder resin by a conventionally known method such as a ball mill, a sand mill, or an attritor. Even if the copolymer having an amine value of 1 to 35 mgKOH / g is added after the dispersion, the effect can be obtained, but the effect is enhanced if it is added before the dispersion. The binder resin may be added before the dispersion or may be added as a resin solution after the dispersion, but it is more effective if it is added before the dispersion. Moreover, it is possible and effective to add chemicals, solvents, additives, and the like necessary for curing (crosslinking) as necessary. Using these coating liquids, they are formed on a conductive substrate using a conventionally known method such as dip coating, spray coating, ring coating, bead coating, or nozzle coating. After the application, it can be produced by drying or heating, and if necessary, drying or curing by a curing treatment such as light irradiation.

  In the present invention, the undercoat layer is functionally separated and at least two layers are laminated in order to achieve both suppression of background contamination, reduction of residual potential and dark decay due to fatigue, prevention of moire, adhesion of the photosensitive layer, and the like. preferable. In this case, the undercoat layer containing the metal oxide and the binder resin is formed in an upper layer than the undercoat layer not containing the metal oxide.

  When the undercoat layer containing the metal oxide and the binder resin is formed under the undercoat layer not containing the metal oxide, the influence on the residual potential is increased. It needs to be included. Accordingly, there is a tendency that the background dirt suppressing effect is slightly reduced. On the other hand, when the subbing layer containing the metal oxide and the binder resin is formed on the subbing layer not containing the metal oxide, the residual potential can be maintained without containing the conductive metal oxide. The impact is relatively small. Therefore, it can be said that it is more preferable in realizing both the soiling and the residual potential. Furthermore, since the charge accumulation property in the charge generation layer is also reduced, the influence on the first round charge reduction is reduced. Therefore, in the present invention, the structure in which the undercoat layer containing the latter metal oxide and the binder resin is formed on the undercoat layer not containing the metal oxide is more preferable.

  Next, a subbing layer that does not contain a metal oxide mainly intended to suppress charge injection from the conductive support will be described. The undercoating layer of the resin alone film containing no metal oxide does not contain a metal oxide, so the effect of increasing the residual potential is large. Therefore, it is necessary to make a thin film, but the charge from the conductive support The effect of suppressing leakage is very high. However, the formation of this undercoat layer has the side effect of significantly increasing the first-cycle charge reduction particularly when a phthalocyanine pigment is used in the charge generation layer. The decrease in the charge of the first round is recovered from the second round as described above, and the cause is that the generation of dark charges by the phthalocyanine pigment being left unattended and the accumulation in the charge generation layer are involved. Conceivable. In addition, since it tends to increase due to fatigue, it is considered that there is also a tendency for the amount of charge accumulation to increase due to fatigue. In this case, it is considered that when an undercoat layer of a resin that does not contain a metal oxide is added, the accumulation of dark charges generated in the charge generation layer is increased, and the effect of lowering the first charge is increased. Due to the fact that the antifouling effect is improved by laminating an undercoat layer containing no metal oxide and an undercoat layer containing a metal oxide and a binder resin, the leakage of charges from the conductive support is It is considered that the effect of charge injection from the conductive support on the first-cycle charge reduction is negligible.

  The following are examples of conventional techniques aimed at suppressing charge injection. As a layer for suppressing charge injection, an anodized film typified by an aluminum oxide layer, an inorganic insulating layer typified by SiO, and a metal oxide glass as described in JP-A-3-191361 A layer formed of a quality network, a layer of polyphosphazene as described in JP-A-3-141363, a layer of an aminosilane reaction product as described in JP-A-3-101737, Other examples include a layer made of an insulating binder resin and a layer made of a curable binder resin. Among them, a layer composed of an insulating binder resin or a curable binder resin that can be formed by a wet coating method can be used favorably. Furthermore, these undercoat layers are laminated with an undercoat layer or a photosensitive layer containing a metal oxide and a binder resin thereon. Therefore, when these are provided by a wet coating method, It is important to be made of a material or composition that is insoluble and does not attack the coating.

In the present invention, a resin is preferably used for the undercoat layer that does not contain a metal oxide, and a conventionally known resin may be used as the resin. Binder resin having a specific resistance of 10 ¹³ Ω · cm or more is preferably used. Examples of the binder resin include thermoplastic resins such as polyamide, polyester, vinyl chloride-vinyl acetate copolymer, and thermosetting resins such as active hydrogen (hydrogen such as —OH group, —NH ₂ group, and —NH group). A thermosetting resin obtained by thermally polymerizing a compound containing a plurality of compounds and a compound containing a plurality of isocyanate groups and / or a compound containing a plurality of epoxy groups can also be used.

  In this case, examples of the compound containing a plurality of active hydrogens include active hydrogens such as polyvinyl butyral, phenoxy resin, phenol resin, polyamide, polyester, polyethylene glycol, polypropylene glycol, polybutylene glycol, and hydroxyethyl methacrylate groups. An acrylic resin etc. are mention | raise | lifted. Examples of the compound containing a plurality of isocyanate groups include tolylene diisocyanate, hexamethylene diisocyanate, diphenylmethane diisocyanate, and prepolymers thereof. Examples of the compound having a plurality of epoxy groups include bisphenol A type epoxy resin. Can be mentioned. Further, a thermosetting resin obtained by thermally polymerizing an oil-free alkyd resin and an amino resin, for example, a butylated melamine resin, and a polyurethane having an unsaturated bond, a resin having an unsaturated bond such as an unsaturated polyester, A photocurable resin such as a combination with a photopolymerization initiator such as a thioxanthone compound or methylbenzyl formate can also be used as the binder resin.

  In the present invention, among these resins, polyamide is preferable, and N-methoxymethylated nylon is most preferable among them. The polyamide resin has a high effect of suppressing charge injection and has a relatively small influence on the residual potential. These polyamide resins are alcohol-soluble resins, are insoluble in ketone solvents, can form a uniform thin film even in dip coating, and have excellent coating properties. In particular, the undercoat layer needs to be a thin film and requires a uniform film thickness, so that the coatability is important in terms of image quality stability.

  In general, however, alcohol-soluble polyamide resins are highly dependent on humidity, which increases resistance in low humidity environments and increases residual potential.In high humidity environments, resistance decreases and causes a decrease in charge. A big problem was a big problem. Among polyamide resins, N-methoxymethylated nylon is most preferably used because its environmental dependency is greatly reduced and stable image quality can always be maintained even when the use environment of the image forming apparatus changes. It is done. In addition, when N-methoxymethylated nylon is used, the film thickness dependence of the residual potential is small, so that it is possible to reduce the influence on the residual potential and obtain a high scumming suppression effect.

  The substitution rate of the alkoxymethyl group in N-methoxymethylated nylon is not particularly limited, but is preferably 15 mol% or more and 45 mol% or less. When the substitution rate of the alkoxymethyl group is higher than 45 mol%, the humidity dependency increases, and when it is lower than 15 mol%, the alcohol solution tends to become cloudy when the alcohol solution is used. Stability may be slightly reduced.

  In the present invention, N-methoxymethylated nylon can be used alone, but various curing agents and acid catalysts can be added depending on circumstances. Conventional materials such as melamine resins and block isocyanate resins that are conventionally known can be used as the crosslinking agent, acidic catalysts can be used as the catalyst, and general-purpose catalysts such as tartaric acid can be used. However, since the insulating property of the undercoat layer is lowered by the addition of the acid catalyst, and the effect of suppressing soiling may be reduced, the addition amount needs to be very small. The addition amount is preferably 5 wt% or less, more preferably 2% or less, based on the resin. In some cases, other binder resins can be mixed. As the binder resin that can be mixed, a polyamide resin exhibiting alcohol solubility is used, and the stability of the liquid with time may be increased.

  In addition, a conductive polymer, an acceptor resin or a low molecular compound, and other various additives can be added in accordance with the charge polarity, which may be effective in reducing the residual potential. However, when the upper layer is laminated by dip coating, these additives may be dissolved out, so the addition amount needs to be kept to a minimum.

  As the coating solvent, any common organic solvent can be used as long as it can dissolve the resin. However, in the case of a polyamide-based resin, alcohol-based solvents such as methanol, ethanol, propanol , Butanol or the like or a mixed solvent thereof is used.

  The undercoat layer is applied by a conventionally known dip coating method, spray coating, ring coating, bead coating, nozzle coating method or the like. After coating, the film formation is completed by heating and drying. However, in the case of curing, a curing treatment such as heating or light irradiation can be performed as necessary.

  The thickness of the undercoat layer is suitably from 0.1 μm to less than 2.0 μm, preferably from 0.3 μm to 1.0 μm. When the thickness of the undercoat layer is larger than that, the residual potential is likely to increase due to repeated charging and exposure, and the environmental dependency tends to increase. On the other hand, if the film thickness is too thin, the background stain suppressing effect becomes poor.

Next, the photosensitive layer will be described.
In the present invention, a laminated type composed of a charge generation layer and a charge transport layer is employed as the photosensitive layer. As a result, it is effective for high sensitivity, and has little influence on the antifouling effect and charge reduction due to fatigue, and is effective for high durability and high stability.

  The charge generation layer is a layer mainly composed of a charge generation material. Any known material can be used as the charge generating substance as long as it is a phthalocyanine pigment. Examples thereof include phthalocyanine pigments such as metal phthalocyanine and metal-free phthalocyanine represented by the following general formula (N). By using these phthalocyanine pigments in the charge generation layer, the background stain tends to be improved, and it is more effective for enhancing the stain resistance than other pigments including azo pigments. The present invention contains a phthalocyanine pigment that is less affected by scumming in the charge generation layer, and by laminating a plurality of subbing layers, the effect of suppressing scumming is further enhanced, and the first-round charge reduction caused by using the phthalocyanine pigment By reducing the side effects of soil on soil, the soil durability and its stability are drastically improved.

式中Ｍ（中心金属）は、金属及び無金属（水素）の元素を表す。ここで挙げられるＭ（中心金属）は、Ｈ、Ｌｉ、Ｂｅ、Ｎａ、Ｍｇ、Ａｌ、Ｓｉ、Ｋ、Ｃａ、Ｓｃ、Ｔｉ、Ｖ、Ｃｒ、Ｍｎ、Ｆｅ、Ｃｏ、Ｎｉ、Ｃｕ、Ｚｎ、Ｇａ、Ｇｅ、Ｙ、Ｚｒ、Ｎｂ、Ｍｏ、Ｔｃ、Ｒｕ、Ｒｈ、Ｐｄ、Ａｇ、Ｃｄ、Ｉｎ、Ｓｎ、Ｓｂ、Ｂａ、Ｈｆ、Ｔａ、Ｗ、Ｒｅ、Ｏｓ、Ｉｒ、Ｐｔ、Ａｕ、Ｈｇ、ＴＩ、Ｌａ、Ｃｅ、Ｐｒ、Ｎｄ、Ｐｍ、Ｓｍ、Ｅｕ、Ｇｄ、Ｔｂ、Ｄｙ、Ｈｏ、Ｅｒ、Ｔｍ、Ｙｂ、Ｌｕ、Ｔｈ、Ｐａ、Ｕ、Ｎｐ、Ａｍ等の単体、もしく酸化物、塩化物、フッ化物、水酸化物、臭化物などの２種以上の元素からなる。中心金属は、これらの元素に限定されるものではない。

In the formula, M (center metal) represents an element of metal and metal free (hydrogen). M (central metal) mentioned here is H, Li, Be, Na, Mg, Al, Si, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga , Ge, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd, In, Sn, Sb, Ba, Hf, Ta, W, Re, Os, Ir, Pt, Au, Hg, TI , La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Th, Pa, U, Np, Am, etc., or oxide, chloride It consists of two or more elements such as fluoride, fluoride, hydroxide and bromide. The central metal is not limited to these elements.

  The charge generation material having a phthalocyanine skeleton in the present invention may have at least a basic skeleton of the general formula (N), a substance having a multimeric structure such as a dimer or trimer, and a higher order high-order substance. It may have a molecular structure. Also, the basic skeleton may have various substituents. Of these various phthalocyanines, titanyl phthalocyanine having TiO as a central metal, metal-free phthalocyanine, chlorogallium phthalocyanine, and the like are particularly preferable from the viewpoint of photoreceptor characteristics. These charge generation materials can be used alone or as a mixture of two or more.

  These phthalocyanines are known to have various crystal systems. For example, in the case of titanyl phthalocyanine, α, β, γ, m, Y type, etc., in the case of copper phthalocyanine, crystals such as α, β, γ, etc. Has a multisystem. Even in the phthalocyanine having the same central metal, various characteristics change as the crystal system changes. It has been reported that the characteristics of photoreceptors using phthalocyanine pigments having these various crystal systems also change accordingly (see Electrophotographic Society Vol. 29, No. 4 (1990)). Therefore, the selection of the phthalocyanine crystal system is very important in terms of the photoreceptor characteristics. In the present invention, in an image forming apparatus that uses a high-sensitivity electrophotographic photosensitive member and performs high-speed output, the first-cycle charge reduction is suppressed, and the stain resistance and stability are improved. It is particularly effective for a photoreceptor using a phthalocyanine pigment effective for increasing sensitivity. These phthalocyanine pigments include a titanyl phthalocyanine pigment having a maximum diffraction peak at 27.2 ° as a diffraction peak (± 0.2 °) of an X-ray diffraction spectrum with a Bragg angle 2θ with respect to CuKα rays (wavelength 1.542 mm). Is mentioned. Further, even when chlorogallium phthalocyanine or hydroxygallium phthalocyanine is used, a high effect can be obtained.

  The binder resin used in the charge generation layer as necessary includes polyamide, polyurethane, epoxy resin, polyketone, polycarbonate, silicone resin, acrylic resin, polyvinyl butyral, polyvinyl formal, polyvinyl ketone, polystyrene, polysulfone, and poly-N-vinyl. Examples include carbazole, polyacrylamide, polyvinyl benzal, polyester, phenoxy resin, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, polyphenylene oxide, polyamide, polyvinyl pyridine, cellulose resin, casein, polyvinyl alcohol, polyvinyl pyrrolidone, and the like. . The amount of the binder resin used in the charge generation layer is 0 to 500 parts by weight, preferably 0 to 200 parts by weight, with respect to 100 parts by weight of the charge generation material. Moreover, various additives, such as leveling agents, a sensitizer, a dispersing agent, etc., such as dimethyl silicone oil and a methylphenyl silicone oil, can be added as needed.

  Examples of the solvent used here include isopropanol, acetone, methyl ethyl ketone, cyclohexanone, tetrahydrofuran, dioxane, ethyl cellosolve, ethyl acetate, methyl acetate, dichloromethane, dichloroethane, monochlorobenzene, cyclohexane, toluene, xylene, ligroin and the like. In particular, ketone solvents, ester solvents, and ether solvents are preferably used. These may be used alone or in combination of two or more. The coating liquid for forming the charge generation layer mainly comprises a charge generation substance, a solvent and a binder resin, and any of these additives such as a sensitizer, a dispersant, a surfactant, and silicone oil are included therein. An agent may be included.

  In the charge generation layer, the charge generation material is dispersed in a suitable solvent together with a binder resin as necessary using a ball mill, attritor, sand mill, ultrasonic wave, etc., and this is applied onto a conductive support and dried. Is formed. The binder resin may be added before or after dispersion.

  As a coating method of the coating liquid, methods such as dip coating, spray coating, bead coating, nozzle coating, spinner coating, and ring coating can be used. The film thickness of the charge generation layer is suitably about 0.01 to 5 μm, preferably 0.05 to 2 μm.

  The charge transport layer can be formed by dissolving or dispersing a charge transport material and a binder resin in an appropriate solvent, and applying and drying the solution on the charge generation layer. Moreover, a plasticizer, a leveling agent, antioxidant, etc. can also be added as needed.

  Charge transport materials include hole transport materials and electron transport materials. Examples of the electron transporting material include chloroanil, bromoanil, tetracyanoethylene, tetracyanoquinodimethane, 2,4,7-trinitro-9-fluorenone, 2,4,5,7-tetranitro-9-fluorenone, 2,4 , 5,7-tetranitroxanthone, 2,4,8-trinitrothioxanthone, 2,6,8-trinitro-4H-indeno [1,2-b] thiophen-4-one, 1,3,7-tri Examples thereof include electron-accepting substances such as nitrodibenzothiophene-5,5-dioxide and benzoquinone derivatives.

  Examples of hole transport materials include poly-N-vinylcarbazole and derivatives thereof, poly-γ-carbazolylethyl glutamate and derivatives thereof, pyrene-formaldehyde condensates and derivatives thereof, polyvinylpyrene, polyvinylphenanthrene, polysilane, oxazole derivatives, Oxadiazole derivatives, imidazole derivatives, monoarylamine derivatives, diarylamine derivatives, triarylamine derivatives, stilbene derivatives, α-phenylstilbene derivatives, benzidine derivatives, diarylmethane derivatives, triarylmethane derivatives, 9-styrylanthracene derivatives, pyrazolines Derivatives, divinylbenzene derivatives, hydrazone derivatives, indene derivatives, butadiene derivatives, pyrene derivatives, etc., bisstilbene derivatives, enamine derivatives, etc. Other known materials may be mentioned. These charge transport materials may be used alone or in combination of two or more.

  Binder resins include polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, poly Vinylidene chloride, polyarylate, phenoxy resin, polycarbonate, cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral, polyvinyl formal, polyvinyl toluene, poly-N-vinylcarbazole, acrylic resin, silicone resin, epoxy resin, melamine resin, urethane resin, phenol Examples thereof include thermoplastic or thermosetting resins such as resins and alkyd resins.

  For the charge transport layer, a polymer charge transport material having both a function as a charge transport material and a function of a binder resin is also preferably used. The charge transport layer composed of these polymer charge transport materials is excellent in wear resistance. As the polymer charge transport material, known materials can be used, and in particular, a polycarbonate containing a triarylamine structure in the main chain and / or side chain is preferably used. Among these, polymer charge transport materials represented by the formulas (I) to (X) are preferably used, and these are exemplified below and specific examples are shown.

式中、Ｒ_１、Ｒ_２、Ｒ_３はそれぞれ独立して置換もしくは無置換のアルキル基又はハロゲン原子、Ｒ_４は水素原子又は置換もしくは無置換のアルキル基、Ｒ_５、Ｒ_６は置換もしくは無置換のアリール基、ｏ、ｐ、ｑはそれぞれ独立して０〜４の整数、ｋ、ｊは組成を表わし、０．１≦ｋ≦１、０≦ｊ≦０．９、ｎは繰り返し単位数を表わし５〜５０００の整数である。Ｘは脂肪族の２価基、環状脂肪族の２価基、または下記一般式で表わされる２価基を表わす。尚、（Ｉ）式は２つの共重合種が交互共重合体の形で記載されているが、ランダム共重合体でも構わない。

In the formula, R ₁ , R ₂ and R ₃ are each independently a substituted or unsubstituted alkyl group or a halogen atom, R ₄ is a hydrogen atom or a substituted or unsubstituted alkyl group, and R ₅ and R ₆ are substituted or unsubstituted. Substituted aryl group, o, p, q are each independently an integer of 0-4, k, j are compositions, 0.1 ≦ k ≦ 1, 0 ≦ j ≦ 0.9, n is the number of repeating units Represents an integer of 5 to 5000. X represents an aliphatic divalent group, a cycloaliphatic divalent group, or a divalent group represented by the following general formula. In the formula (I), two copolymer species are described in the form of an alternating copolymer, but a random copolymer may be used.

Ｒ_１０１、Ｒ_１０２は各々独立して置換もしくは無置換のアルキル基、アリール基またはハロゲン原子を表わす。ｌ、ｍは０〜４の整数、Ｙは単結合、炭素原子数１〜１２の直鎖状、分岐状もしくは環状のアルキレン基、−Ｏ−、−Ｓ−、−ＳＯ−、−ＳＯ_２−、−ＣＯ−、−ＣＯ−Ｏ−Ｚ−Ｏ−ＣＯ−（式中Ｚは脂肪族の２価基を表わす。）または、

R _{101 and} R ₁₀₂ each independently represents a substituted or unsubstituted alkyl group, aryl group or halogen atom. l and m are integers of 0 to 4, Y is a single bond, a linear, branched or cyclic alkylene group having 1 to 12 carbon atoms, —O—, —S—, —SO—, —SO ₂ —. , -CO-, -CO-O-Z-O-CO- (wherein Z represents an aliphatic divalent group), or

（ａは１〜２０の整数、ｂは１〜２０００の整数、Ｒ_１０３、Ｒ_１０４は置換または無置換のアルキル基又はアリール基を表わす）を表わす。ここで、Ｒ_１０１とＲ_１０２、Ｒ_１０３とＲ_１０４は、それぞれ同一でも異なってもよい。）

(A is an integer of 1 to 20, b is an integer of 1 to 2000, and R ₁₀₃ and R ₁₀₄ represent a substituted or unsubstituted alkyl group or aryl group). Here, R ₁₀₁ and R ₁₀₂ , and R ₁₀₃ and R ₁₀₄ may be the same or different. )

式中、Ｒ_７、Ｒ_８は置換もしくは無置換のアリール基、Ａｒ_１、Ａｒ_２、Ａｒ_３は同一又は異なるアリレン基を表わす。Ｘ、ｋ、ｊおよびｎは、（Ｉ）式の場合と同じである。尚、（II）式は２つの共重合種が交互共重合体の形で記載されているが、ランダム共重合体でも構わない。

In the formula, R ₇ and R ₈ represent a substituted or unsubstituted aryl group, and Ar ₁ , Ar ₂ , and Ar ₃ represent the same or different arylene groups. X, k, j and n are the same as those in the formula (I). In the formula (II), two copolymer species are described in the form of an alternating copolymer, but a random copolymer may be used.

式中、Ｒ_９、Ｒ_１０は置換もしくは無置換のアリール基、Ａｒ_４、Ａｒ_５、Ａｒ_６は同一又は異なるアリレン基を表わす。Ｘ、ｋ、ｊおよびｎは、（Ｉ）式の場合と同じである。尚、（III）式は２つの共重合種が交互共重合体の形で記載されているが、ランダム共重合体でも構わない。

In the formula, R ₉ and R ₁₀ represent a substituted or unsubstituted aryl group, and Ar ₄ , Ar ₅ , and Ar ₆ represent the same or different arylene groups. X, k, j and n are the same as those in the formula (I). In the formula (III), two copolymer species are described in the form of an alternating copolymer, but a random copolymer may be used.

式中、Ｒ_１１、Ｒ_１２、は置換もしくは無置換のアリール基、Ａｒ_７、Ａｒ₈、Ａｒ₉は同一又は異なるアリレン基、ｐは１〜５の整数を表わす。Ｘ、ｋ、ｊおよびｎは、（Ｉ）式の場合と同じである。尚、（IV）式は２つの共重合種が交互共重合体の形で記載されているが、ランダム共重合体でも構わない

In the formula, R ₁₁ and R ₁₂ are substituted or unsubstituted aryl groups, Ar ₇ , Ar ₈ and Ar ₉ are the same or different arylene groups, and p represents an integer of 1 to 5. X, k, j and n are the same as those in the formula (I). In the formula (IV), two copolymer species are described in the form of an alternating copolymer, but a random copolymer may be used.

式中、Ｒ_１３、Ｒ_１４は置換もしくは無置換のアリール基、Ａｒ_１０、Ａｒ_１１、Ａｒ_１２は同一又は異なるアリレン基、Ｘ_１、Ｘ_２は置換もしくは無置換のエチレン基、又は置換もしくは無置換のビニレン基を表わす。Ｘ、ｋ、ｊおよびｎは、（Ｉ）式の場合と同じである。尚、（Ｖ）式は２つの共重合種が交互共重合体の形で記載されているが、ランダム共重合体でも構わない。

In the formula, R ₁₃ and R ₁₄ are substituted or unsubstituted aryl groups, Ar ₁₀ , Ar ₁₁ and Ar ₁₂ are the same or different arylene groups, X ₁ and X ₂ are substituted or unsubstituted ethylene groups, or substituted or unsubstituted Represents a substituted vinylene group. X, k, j and n are the same as those in the formula (I). In the formula (V), two copolymer species are described in the form of an alternating copolymer, but a random copolymer may be used.

式中、Ｒ_１５、Ｒ_１６、Ｒ_１７、Ｒ_１８は置換もしくは無置換のアリール基、Ａｒ_１３、Ａｒ_１４、Ａｒ_１５、Ａｒ_１６は同一又は異なるアリレン基、Ｙ_１、Ｙ_２、Ｙ_３は単結合、置換もしくは無置換のアルキレン基、置換もしくは無置換のシクロアルキレン基、置換もしくは無置換のアルキレンエーテル基、酸素原子、硫黄原子、ビニレン基を表わし同一であっても異なってもよい。Ｘ、ｋ、ｊおよびｎは、（Ｖ）式の場合と同じである。尚、（VI）式は２つの共重合種が交互共重合体の形で記載されているが、ランダム共重合体でも構わない。

In the formula, R ₁₅ , R ₁₆ , R ₁₇ , R ₁₈ are substituted or unsubstituted aryl groups, Ar ₁₃ , Ar ₁₄ , Ar ₁₅ , Ar ₁₆ are the same or different arylene groups, Y ₁ , Y ₂ , Y ₃ are A single bond, a substituted or unsubstituted alkylene group, a substituted or unsubstituted cycloalkylene group, a substituted or unsubstituted alkylene ether group, an oxygen atom, a sulfur atom, or a vinylene group may be the same or different. X, k, j, and n are the same as in the case of equation (V). In the formula (VI), two copolymer species are described in the form of an alternating copolymer, but a random copolymer may be used.

式中、Ｒ_１９、Ｒ_２０は水素原子、置換もしくは無置換のアリール基を表わし，Ｒ_１９とＲ_２０は環を形成していてもよい。Ａｒ_１７、Ａｒ_１８、Ａｒ_１９は同一又は異なるアリレン基を表わす。Ｘ、ｋ、ｊおよびｎは、（Ｉ）式の場合と同じである。尚、（VII）式は２つの共重合種が交互共重合体の形で記載されているが、ランダム共重合体でも構わない。

In the formula, R ₁₉ and R _{20 each} represent a hydrogen atom or a substituted or unsubstituted aryl group, and R ₁₉ and R ₂₀ may form a ring. Ar ₁₇ , Ar ₁₈ and Ar ₁₉ represent the same or different arylene groups. X, k, j and n are the same as those in the formula (I). In the formula (VII), two copolymer species are described in the form of an alternating copolymer, but a random copolymer may be used.

式中、Ｒ_２１は置換もしくは無置換のアリール基、Ａｒ_２０、Ａｒ_２１、Ａｒ_２２、Ａｒ_２３は同一又は異なるアリレン基を表わす。Ｘ、ｋ、ｊおよびｎは、（Ｉ）式の場合と同じである。尚、（VIII）式は２つの共重合種が交互共重合体の形で記載されているが、ランダム共重合体でも構わない。

In the formula, R ₂₁ represents a substituted or unsubstituted aryl group, and Ar ₂₀ , Ar ₂₁ , Ar ₂₂ , and Ar ₂₃ represent the same or different arylene groups. X, k, j and n are the same as those in the formula (I). In the formula (VIII), two copolymer species are described in the form of an alternating copolymer, but a random copolymer may be used.

式中、Ｒ_２２、Ｒ_２３、Ｒ_２４、Ｒ_２５は置換もしくは無置換のアリール基、Ａｒ_２４、Ａｒ_２５、Ａｒ_２６、Ａｒ_２７、Ａｒ_２８は同一又は異なるアリレン基を表わす。Ｘ、ｋ、ｊおよびｎは、（Ｉ）式の場合と同じである。尚、（IX）式は２つの共重合種が交互共重合体の形で記載されているが、ランダム共重合体でも構わない。

In the formula, R ₂₂ , R ₂₃ , R ₂₄ and R ₂₅ represent a substituted or unsubstituted aryl group, and Ar ₂₄ , Ar ₂₅ , Ar ₂₆ , Ar ₂₇ and Ar ₂₈ represent the same or different arylene groups. X, k, j and n are the same as those in the formula (I). In the formula (IX), two copolymer species are described in the form of an alternating copolymer, but a random copolymer may be used.

式中、Ｒ_２６、Ｒ_２７は置換もしくは無置換のアリール基、Ａｒ_２９、Ａｒ_３０、Ａｒ_３１は同一又は異なるアリレン基を表わす。Ｘ、ｋ、ｊおよびｎは、（Ｉ）式の場合と同じである。尚、（Ｘ）式は２つの共重合種が交互共重合体の形で記載されているが、ランダム共重合体でも構わない。

In the formula, R ₂₆ and R ₂₇ represent a substituted or unsubstituted aryl group, and Ar ₂₉ , Ar ₃₀ and Ar ₃₁ represent the same or different arylene groups. X, k, j and n are the same as those in the formula (I). In the formula (X), two copolymer species are described in the form of an alternating copolymer, but a random copolymer may be used.

  The amount of the charge transport material is 20 to 300 parts by weight, preferably 40 to 150 parts by weight, based on 100 parts by weight of the binder resin. The thickness of the charge transport layer is 5 to 100 μm, preferably about 10 to 40 μm.

  As the solvent used here, tetrahydrofuran, dioxane, toluene, dichloromethane, monochlorobenzene, dichloroethane, cyclohexanone, methyl ethyl ketone, acetone and the like are used. Among them, it is desirable to use non-halogen solvents for the purpose of reducing environmental burdens. Specifically, cyclic ethers such as tetrahydrofuran, dioxolane and dioxane, aromatic hydrocarbons such as toluene and xylene, and derivatives thereof. However, it is also used favorably in terms of the antifouling effect.

  In the present invention, a plasticizer or a leveling agent may be added to the charge transport layer. As the plasticizer, those used as a plasticizer for general resins such as dibutyl phthalate and dioctyl phthalate can be used as they are, and the amount used is suitably about 0 to 30% by weight based on the binder resin. As the leveling agent, silicone oils such as dimethyl silicone oil and methylphenyl silicone oil, polymers or oligomers having a perfluoroalkyl group in the side chain are used, and the amount used is 0 to 1 with respect to the binder resin. Weight percent is appropriate.

In the electrophotographic photoreceptor of the present invention, a protective layer mainly intended to improve the wear resistance of the photoreceptor can be laminated on the outermost surface of the photoreceptor, which is effective and useful. As a result, it is possible to suppress an increase in electric field strength due to repeated use, which is more effective for suppressing background contamination and suppressing first-cycle charge reduction. The protective layer formed in the present invention reduces the influence of abrasion caused by repeated use of the photoreceptor, improves the stain resistance, and further improves the electrostatic characteristics and image stability, thereby extending the life of the photoreceptor. It is formed for the purpose of achieving the above.
In the present invention, any protective layer that is effective for improving the abrasion resistance of the photoreceptor can suppress an increase in electric field strength in repeated use, and thus any protective layer can be applied. Even if the durability is improved, there is a side effect on electrostatic characteristics or image characteristics such as an increase in residual potential and image flow, and as a result, it is not preferable if the life of the photoreceptor is not increased. In the present invention, among the protective layers, at least a protective layer composed of a metal oxide, a charge transport material and a binder resin, or a radical polymerizable monomer having no charge transport structure and a radical polymerizable compound having a charge transport structure, A protective layer comprising a cross-linked charge transport layer obtained by curing is preferred. These protective layers are excellent in abrasion resistance of the photoreceptor, have little increase in residual potential in repeated use, and are effective for extending the life of the photoreceptor.
The former protective layer comprising a metal oxide, a charge transport material and a binder resin will be described below.
As the metal oxide contained in the protective layer made of a metal oxide, a charge transport material and a binder resin, a known metal oxide can be used, but it is effective for improving the abrasion resistance of the photoreceptor. It is necessary to choose. Specific examples include metal oxides such as silica, alumina, titanium oxide, tin oxide, zinc oxide, indium oxide, antimony oxide, bismuth oxide, antimony-doped tin oxide, and tin-doped indium oxide. The metal oxide contained in the protective layer needs to be selected not only with high wear resistance but also with high specific resistance. Conductive metal oxides having a low specific resistance are likely to diffuse before the charge generated in the charge generation layer of the photoreceptor reaches the surface of the protective layer, thereby causing image flow. There is a risk that a sufficient effect cannot be obtained for extending the service life. The specific resistance is preferably 10 ⁷ Ω · cm or more, and alumina, titanium oxide, and silica are preferably used. Among these, α-alumina, which is excellent in wear resistance and hardly causes image blurring, is particularly effectively used.
The average primary particle size of the metal oxide is preferably 0.1 μm to 0.9 μm, and more preferably 0.2 to 0.5 μm. If the average primary particle size is larger than this, the residual potential may increase or the resolving power may decrease. If the average primary particle size is smaller than this, a sufficient effect for improving the wear resistance may be obtained. May not be obtained.
The content of the metal oxide is preferably 1% by weight to 50% by weight and more preferably 10% by weight to 30% by weight based on the total solid content contained in the protective layer. If the content of the metal oxide is higher than this, the residual potential increases, causing a reduction in image quality. If the content of the metal oxide is lower than this, no effect is obtained for improving the wear resistance. There is a case.
The charge transport material and binder resin described in the charge transport layer can be used as the charge transport material and binder resin contained in the protective layer comprising a metal oxide, a charge transport material and a binder resin. By containing the metal oxide and the charge transport material, it is possible to improve wear resistance and reduce residual potential. As the binder resin, the above-described polymer charge transport material can also be used effectively, and a further effect can be obtained in improving wear resistance.
A dispersant can be further added to the protective layer made of a metal oxide, a charge transport material, and a binder resin, and a further effect can be obtained for reducing residual potential and improving wear resistance. is there. Further, by improving the dispersibility of the metal oxide, an effect can be obtained for suppressing uneven wear of the photosensitive member and reduction in resolution. Furthermore, since the surface smoothness is enhanced, it is effective for reducing cleaning defects.
As the dispersant, any dispersant can be used as long as it is effective in improving the wettability and dispersibility of the metal oxide, but among the commercially available dispersants, a dispersion having an acid value. The agent is particularly effective for reducing the residual potential and is particularly preferably used. These high acid value dispersants dramatically improve the dispersibility of the metal oxide when a metal oxide or binder resin that does not exhibit acidity is used. In particular, when α-alumina is used as the metal oxide and polycarbonate or polyarylate is used as the binder resin, the effect is high, and the residual potential reduction effect is also greatly improved.
As an acid value of a dispersing agent, 10-700 (mgKOH / g) is preferable, and 30-200 (mgKOH / g) is especially preferable. The acid value is defined as the number of milligrams of potassium hydroxide required to neutralize free fatty acids contained in 1 g. Examples of the dispersant satisfying these requirements include a polycarboxylic acid type wetting dispersant, and among them, BYK-P104 manufactured by BYK Chemie is particularly preferably used.
A protective layer comprising a metal oxide, a charge transport material and a binder resin is obtained by dispersing the metal oxide together with a solvent, and optionally a binder resin and a dispersant by a conventionally known method such as a ball mill, a sand mill, or an attritor. A coating solution can be obtained. Binder resin and dispersant may be added before dispersion or after dispersion as a resin solution, but the dispersion stability is improved by adding the dispersant before dispersion and the binder resin as a solution after dispersion. A tendency is seen and preferable.
The protective layer composed of the metal oxide, the charge transport material and the binder resin can be applied by a conventionally known method using the above-described coating solution. For example, it is formed on the conductive substrate using a dip coating method, spray coating, ring coating, bead coating, nozzle coating method or the like. Of these, the spray coating method is most preferably used.
1-10 micrometers is preferable and, as for the protective layer which consists of a metal oxide obtained by the above, a charge transport material, and binder resin, 2-6 micrometers is more preferable. If the film thickness is larger than this, the residual potential may be increased or the resolution may be decreased. If the film thickness is smaller than this, the effect on the wear resistance is reduced.

Next, a protective layer comprising the latter cross-linked charge transport layer will be described (hereinafter, this protective layer is simply referred to as a cross-linked charge transport layer).
The cross-linked charge transport layer has wear resistance equivalent to or higher than that of a protective layer made of a metal oxide, a charge transport material and a binder resin, has little effect on the residual potential, and has excellent cleaning properties. Since it is also possible to reduce the influence of image defects due to filming or adhesion of foreign matter, it is possible to obtain a further effect for extending the life of the photoreceptor.

  Scratches formed on the surface of the photosensitive member and foreign matters (toner, toner external additives, carrier, paper dust, etc.) adhering to the surface decrease the cleaning property of the photosensitive member and significantly reduce the image quality stability. Therefore, in order to achieve high durability of the photoconductor, it is important not only to increase the wear resistance, but also to minimize the effects of scratches and filming on the surface of the photoconductor. It is preferable to form a highly elastic and smooth surface layer.

  The crosslinkable charge transport layer formed on the surface of the present invention is obtained by curing a radical polymerizable monomer having no charge transport structure and a radical polymerizable compound having a charge transport structure. It is particularly effective for extending the life of a photoreceptor when a trifunctional or higher-functional radical polymerizable monomer and a radical polymerizable compound having a monofunctional charge transporting structure are cured. Since this crosslinkable charge transport layer has a crosslink structure obtained by curing a tri- or higher functional radical polymerizable monomer, a three-dimensional network structure is developed, and a highly hard and highly elastic surface layer having a very high crosslink density is obtained. In addition, it is uniform and high in smoothness, and high wear resistance and scratch resistance are achieved. Thus, it is important to increase the crosslink density on the surface of the photoreceptor, that is, the number of crosslink bonds per unit volume. However, since a large number of bonds are instantaneously formed in the curing reaction, internal stress due to volume shrinkage occurs. Since this internal stress increases as the film thickness of the crosslinkable charge transport layer increases, cracks and film peeling tend to occur when the entire charge transport layer is cured. Even if this phenomenon does not appear initially, it may be likely to occur over time due to repeated use in the electrophotographic process and the influence of charging, development, transfer, cleaning hazards and thermal fluctuations.

  As a method for solving this problem, (1) a polymer component is introduced into the crosslinked layer and the crosslinked structure, (2) a large amount of monofunctional and bifunctional radically polymerizable monomers are used, and (3) a flexible group is introduced. Although the directionality which makes a cured resin layer soft, such as using the polyfunctional monomer which has, is mentioned, the crosslink density of a bridge | crosslinking layer becomes thin in any case, and remarkable wear resistance is not achieved. On the other hand, the photoconductor of the present invention is provided with a cross-linked charge transport layer having a high cross-linking density and having a three-dimensional network structure developed on the charge transport layer with a film thickness of 1 μm or more and 10 μm or less. No film peeling occurs and very high wear resistance is achieved. By selecting a film thickness of the crosslinkable charge transport layer of 2 μm or more and 8 μm or less, in addition to further improving the margin for the above problem, a material selection for increasing the crosslink density that leads to further improvement in wear resistance. Is possible.

  The reason why the photoconductor of the present invention can suppress cracking and film peeling is that the cross-linked charge transport layer can be made thin, so that the internal stress does not increase, and since the charge transport layer is provided in the lower layer, the surface of the cross-linked charge transport layer This is because internal stress can be relaxed. For this reason, it is not necessary to contain a large amount of polymer material in the cross-linked charge transport layer, and the polymer material and radical polymerizable composition (radical polymerizable monomer or radical polymerizable compound having a charge transport structure) generated at this time. Scratches and toner filming due to incompatibility with the cured product resulting from this reaction are unlikely to occur.

  Further, when a thick film over the entire charge transport layer is cured by light energy irradiation, light transmission from the absorption by the charge transport structure to the inside is limited, and a phenomenon in which the curing reaction does not proceed sufficiently may occur. In the cross-linked charge transport layer of the present invention, when it is a thin film having a thickness of 10 μm or less, the curing reaction proceeds particularly uniformly to the inside, and high wear resistance tends to be maintained inside as well as the surface. In addition, in the formation of the crosslinkable charge transport layer of the present invention, in addition to the trifunctional radical polymerizable monomer, a radical polymerizable compound having a monofunctional charge transporting structure is contained, which is the trifunctional Incorporated into the cross-linking bond at the time of curing the above radical polymerizable monomer.

  On the other hand, when a low molecular charge transport material having no functional group is contained in the cross-linked surface layer, precipitation of the low molecular charge transport material and white turbidity occur due to its low compatibility, and the cross-linked surface layer The mechanical strength also decreases. On the other hand, when a bifunctional or higher-functional charge transporting compound is used as the main component, the crosslink structure is fixed by a plurality of bonds and the crosslink density is further increased, but the charge transporting structure is very bulky, so that the cured resin structure is distorted. Becomes very large, which increases the internal stress of the cross-linked charge transport layer.

  Furthermore, the photoreceptor of the present invention has good electrical characteristics, and therefore has excellent repetitive stability, realizing high durability and high stability. This is because a radically polymerizable compound having a monofunctional charge transporting structure is used as a constituent material of the crosslinkable charge transport layer and is immobilized in a pendant shape between the crosslinks. As described above, the charge transport material having no functional group causes precipitation and clouding phenomenon, and the electrical characteristics are remarkably deteriorated in repeated use such as reduction in sensitivity and increase in residual potential. When a bifunctional or higher-functional charge transporting compound is used as the main component, it is fixed in the crosslinked structure with a plurality of bonds, so the intermediate structure (cation radical) during charge transport cannot be kept stable, Sensitivity decreases due to traps and residual potential increases. Such deterioration of the electric characteristics appears as an image such as a decrease in image density and thinning of characters. Furthermore, in the photoreceptor of the present invention, the high charge mobility design with less charge trapping of the conventional photoreceptor can be applied as the lower charge transport layer, and the electrical side effects of the cross-linked charge transport layer can be minimized. it can.

  Furthermore, in the formation of the crosslinkable charge transport layer of the present invention, the drastic wear resistance is exhibited particularly by making the crosslinkable charge transport layer insoluble in the organic solvent. The cross-linked charge transport layer of the present invention is formed by curing a tri- or higher functional radical polymerizable monomer having no charge transport structure and a radical polymerizable compound having a monofunctional charge transport structure. Although a three-dimensional network structure develops and has a high crosslinking density, it contains from other than the above components (for example, mono- or bifunctional monomers, polymer binders, antioxidants, leveling agents, plasticizers and other additives and lower layers) In some cases, the cross-linking density is locally dilute or the aggregate is formed of fine cured products cross-linked with high density.

  Such a crosslinkable charge transport layer has a weak bonding force between cured products and is soluble in an organic solvent, and is repeatedly used in an electrophotographic process. Elimination is likely to occur. By making the cross-linkable charge transport layer insoluble in an organic solvent as in the present invention, the original three-dimensional network structure is developed and has a high degree of cross-linking, and the chain reaction proceeds in a wide range to obtain a cured product. Since the polymer has a high molecular weight, a dramatic improvement in wear resistance is achieved.

Next, the constituent materials of the crosslinkable charge transport layer coating solution of the present invention will be described.
The trifunctional or higher functional radical polymerizable monomer having no charge transporting property used in the present invention is a hole transporting structure such as triarylamine, hydrazone, pyrazoline, carbazole, such as condensed polycyclic quinone, diphenoquinone, cyano group. And a monomer having no electron transport structure such as an electron-withdrawing aromatic ring having a nitro group and having three or more radical polymerizable functional groups. The radical polymerizable functional group may be any group as long as it has a carbon-carbon double bond and is capable of radical polymerization. Examples of these radical polymerizable functional groups include 1-substituted ethylene functional groups and 1,1-substituted ethylene functional groups shown below.

[1] Examples of the 1-substituted ethylene functional group include functional groups represented by the following formula (10).

(In the formula, X ₁ is an arylene group such as a phenylene group or a naphthylene group which may have a substituent, an alkenylene group which may have a substituent, a —CO— group, a —COO— group. , —CON (R ₁₀ ) — group (R ₁₀ represents an alkyl group such as hydrogen, methyl group or ethyl group, an aralkyl group such as benzyl group, naphthylmethyl group or phenethyl group, or an aryl group such as phenyl group or naphthyl group. Or the —S— group.)

Specific examples of these substituents include a vinyl group, a styryl group, a 2-methyl-1,3-butadienyl group, a vinylcarbonyl group, an acryloyloxy group, an acryloylamide group, and a vinyl thioether group.
[2] Examples of the 1,1-substituted ethylene functional group include functional groups represented by the following formula (11).

(In the formula, Y is an aryl group such as an alkyl group which may have a substituent, an aralkyl group which may have a substituent, a phenyl group which may have a substituent, or a naphthyl group. Group, halogen atom, cyano group, nitro group, alkoxy group such as methoxy group or ethoxy group, -COOR ₁₁ group (R ₁₁ is a hydrogen atom, an alkyl such as an optionally substituted methyl group or ethyl group) Group, an aralkyl group such as benzyl which may have a substituent, a phenethyl group or the like, an aryl group such as a phenyl group or a naphthyl group which may have a substituent, or -CONR ₁₂ R ₁₃ (R ₁₂ and R ₁₃ is a hydrogen atom, which may have a substituent an alkyl group such as methyl group and ethyl group, which may have a substituent group benzyl group, naphthylmethyl group, or Ara such phenethyl group, Kill group or substituent a phenyl group which may have a, an aryl group such as a naphthyl group, which may be the same or different from each other.) Further, X ₂ and X ₁ in the formula (10) Represents the same substituent, a single bond, and an alkylene group, provided that at least one of Y and X ₂ is an oxycarbonyl group, a cyano group, an alkenylene group, and an aromatic ring.)

  Specific examples of these substituents include an α-acryloyloxy chloride group, a methacryloyloxy group, an α-cyanoethylene group, an α-cyanoacryloyloxy group, an α-cyanophenylene group, and a methacryloylamino group.

In addition, examples of the substituent further substituted with the substituent for X and Y include, for example, a halogen atom, a nitro group, an alkyl group such as a cyano group, a methyl group, and an ethyl group, an alkoxy group such as a methoxy group and an ethoxy group, Examples thereof include aryloxy groups such as phenoxy group, aryl groups such as phenyl group and naphthyl group, aralkyl groups such as benzyl group and phenethyl group.
Among these radical polymerizable functional groups, acryloyloxy group and methacryloyloxy group are particularly useful, and a compound having three or more acryloyloxy groups is, for example, a compound having three or more hydroxyl groups in the molecule and an acrylic group. It can be obtained by using an acid (salt), an acrylic acid halide, or an acrylic ester to cause an ester reaction or a transesterification reaction. A compound having three or more methacryloyloxy groups can be obtained in the same manner. Further, the radical polymerizable functional groups in the monomer having three or more radical polymerizable functional groups may be the same or different.

Specific examples of the trifunctional or higher functional radical polymerizable monomer having no charge transporting structure include the following, but are not limited to these compounds.
That is, examples of the radical polymerizable monomer used in the present invention include trimethylolpropane triacrylate (TMPTA), trimethylolpropane trimethacrylate, trimethylolpropane alkylene-modified triacrylate, trimethylolpropane ethyleneoxy-modified (hereinafter referred to as EO modification). ) Triacrylate, trimethylolpropane propyleneoxy modified (hereinafter PO modified) triacrylate, trimethylolpropane caprolactone modified triacrylate, trimethylolpropane alkylene modified trimethacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate (PETTA), glycerol triacrylate Glycerol epichlorohydrin modified (hereinafter ECH modified) Acrylate, glycerol EO modified triacrylate, glycerol PO modified triacrylate, tris (acryloxyethyl) isocyanurate, dipentaerythritol hexaacrylate (DPHA), dipentaerythritol caprolactone modified hexaacrylate, dipentaerythritol hydroxypentaacrylate, alkylated di Pentaerythritol pentaacrylate, alkylated dipentaerythritol tetraacrylate, alkylated dipentaerythritol triacrylate, dimethylolpropane tetraacrylate (DTMPTA), pentaerythritol ethoxytetraacrylate, phosphoric acid EO-modified triacrylate, 2, 2, 5, 5 , -Tetrahydroxymethylcyclopentanone tetraacrylate And the like, which can be used in combination either alone or in combination.

  The trifunctional or higher functional radical polymerizable monomer having no charge transport structure used in the present invention has a molecular weight relative to the number of functional groups in the monomer in order to form a dense crosslink in the crosslinkable charge transport layer. The ratio (molecular weight / functional group number) is preferably 250 or less. Further, when this ratio is larger than 250, the cross-linked charge transport layer is soft and wear resistance is somewhat lowered. Therefore, among monomers exemplified above, monomers having a modifying group such as EO, PO, caprolactone, etc. It is not preferable to use a compound having a long modifying group alone.

  Further, the proportion of the trifunctional or higher functional radical polymerizable monomer having no charge transport structure used in the crosslinkable charge transport layer is 20 to 80% by weight, preferably 30 to 70% by weight based on the total amount of the crosslinkable charge transport layer. %. When the monomer component is less than 20% by weight, the three-dimensional crosslink density of the crosslinkable charge transport layer is small, and a drastic improvement in wear resistance is not achieved as compared with the case of using a conventional thermoplastic binder resin. On the other hand, if it is 80% by weight or more, the content of the charge transporting compound is lowered, and the electrical characteristics are deteriorated. The electrical characteristics and abrasion resistance required differ depending on the process used, and the film thickness of the cross-linked charge transport layer of the photoreceptor varies accordingly. A range of 70% by weight is most preferred.

  The radical polymerizable compound having a monofunctional charge transport structure used in the crosslinked charge transport layer of the present invention is, for example, a hole transport structure such as triarylamine, hydrazone, pyrazoline, carbazole, such as condensed polycyclic quinone. , A compound having an electron transport structure such as diphenoquinone, an electron-withdrawing aromatic ring having a cyano group or a nitro group, and having one radical polymerizable functional group. Examples of the radical polymerizable functional group include those shown in the above radical polymerizable monomer, and acryloyloxy group and methacryloyloxy group are particularly useful. In addition, a triarylamine structure is highly effective as a charge transporting structure, and in particular, when a compound represented by the structure of the following general formula (1) or (2) is used, electrical characteristics such as sensitivity and residual potential are obtained. Is well maintained.

(In the formula, R ₁ represents a hydrogen atom, a halogen atom, an alkyl group which may have a substituent, an aralkyl group which may have a substituent, an aryl group which may have a substituent, a cyano group, a nitro group, Group, alkoxy group, —COOR ₇ (R ₇ is a hydrogen atom, an alkyl group which may have a substituent, an aralkyl group which may have a substituent or an aryl group which may have a substituent), halogen Carbonyl group or CONR ₈ R ₉ (R ₈ and R ₉ may have a hydrogen atom, a halogen atom, an alkyl group which may have a substituent, an aralkyl group which may have a substituent, or a substituent. Ar ₁ and Ar ₂ represent a substituted or unsubstituted arylene group, and may be the same or different.Ar ₃ , which may be the same or different from each other. Ar ₄ may be substituted Represents an unsubstituted aryl group, which may be the same or different, X represents a single bond, a substituted or unsubstituted alkylene group, a substituted or unsubstituted cycloalkylene group, a substituted or unsubstituted alkylene ether group, An oxygen atom, a sulfur atom, or a vinylene group, Z represents a substituted or unsubstituted alkylene group, a substituted or unsubstituted alkylene ether group, or an alkyleneoxycarbonyl group, and m and n represent an integer of 0 to 3.)

Specific examples of those represented by the general formulas (1) and (2) are shown below.
In the general formulas (1) and (2), in the substituent of R ₁ , examples of the alkyl group include a methyl group, an ethyl group, a propyl group, and a butyl group, and examples of the aryl group include a phenyl group and a naphthyl group. The aralkyl group includes a benzyl group, a phenethyl group, and a naphthylmethyl group, and the alkoxy group includes a methoxy group, an ethoxy group, a propoxy group, and the like. These include a halogen atom, a nitro group, a cyano group, and a methyl group. Substituted with an alkyl group such as an ethyl group, an alkoxy group such as a methoxy group or an ethoxy group, an aryloxy group such as a phenoxy group, an aryl group such as a phenyl group or a naphthyl group, an aralkyl group such as a benzyl group or a phenethyl group, etc. May be.

Of the substituents for R ₁ , particularly preferred are a hydrogen atom and a methyl group.
Substituted or unsubstituted Ar ₃ and Ar ₄ are aryl groups, and examples of the aryl group include condensed polycyclic hydrocarbon groups, non-fused cyclic hydrocarbon groups, and heterocyclic groups.

  The condensed polycyclic hydrocarbon group preferably has 18 or less carbon atoms forming a ring, for example, a pentanyl group, an indenyl group, a naphthyl group, an azulenyl group, a heptaenyl group, a biphenylenyl group, an as-indacenyl group. , S-indacenyl group, fluorenyl group, acenaphthylenyl group, preadenyl group, acenaphthenyl group, phenalenyl group, phenanthryl group, anthryl group, fluoranthenyl group, acephenanthrenyl group, aceanthrylenyl group, triphenylyl group, pyrenyl group , A chrycenyl group, a naphthacenyl group, and the like.

  Examples of the non-fused cyclic hydrocarbon group include monovalent groups of monocyclic hydrocarbon compounds such as benzene, diphenyl ether, polyethylene diphenyl ether, diphenyl thioether and diphenyl sulfone, or biphenyl, polyphenyl, diphenylalkane, diphenylalkene, diphenylalkyne, Monovalent groups of non-condensed polycyclic hydrocarbon compounds such as triphenylmethane, distyrylbenzene, 1,1-diphenylcycloalkane, polyphenylalkane, and polyphenylalkene, or ring assemblies such as 9,9-diphenylfluorene And monovalent groups of hydrocarbon compounds.

  Examples of the heterocyclic group include monovalent groups such as carbazole, dibenzofuran, dibenzothiophene, oxadiazole, and thiadiazole.

The aryl group represented by Ar ₃ or Ar ₄ may have a substituent as shown below, for example.
(1) Halogen atom, cyano group, nitro group and the like.
(2) Alkyl groups, preferably C ₁ -C _12, especially C ₁ -C ₈ , more preferably C ₁ -C ₄ linear or branched alkyl groups, further including fluorine atoms , a hydroxyl group, a cyano _group, an alkoxy group of C 1 -C _4, a phenyl group or a halogen _atom, which may have a phenyl group substituted by an alkoxy group C 1 -C ₄ alkyl or _C 1 -C ₄ Good. Specifically, methyl group, ethyl group, n-butyl group, i-propyl group, t-butyl group, s-butyl group, n-propyl group, trifluoromethyl group, 2-hydroxyethyl group, 2-ethoxyethyl Group, 2-cyanoethyl group, 2-methoxyethyl group, benzyl group, 4-chlorobenzyl group, 4-methylbenzyl group, 4-phenylbenzyl group and the like.
(3) An alkoxy group (—OR ₂ ), and R ₂ represents the alkyl group defined in (2). Specifically, methoxy group, ethoxy group, n-propoxy group, i-propoxy group, t-butoxy group, n-butoxy group, s-butoxy group, i-butoxy group, 2-hydroxyethoxy group, benzyloxy group And a trifluoromethoxy group.
(4) An aryloxy group, and examples of the aryl group include a phenyl group and a naphthyl group. It _may contain an alkoxy group having C 1 -C _4, alkyl group, or a halogen atom C 1 -C ₄ as a substituent. Specific examples include a phenoxy group, a 1-naphthyloxy group, a 2-naphthyloxy group, a 4-methoxyphenoxy group, and a 4-methylphenoxy group.
(5) Alkyl mercapto group or aryl mercapto group, and specific examples include methylthio group, ethylthio group, phenylthio group, p-methylphenylthio group and the like.
(6)

（式中、Ｒ_３及びＲ_４は各々独立に水素原子、前記（２）で定義したアルキル基、またはアリール基を表わす。アリール基としては、例えばフェニル基、ビフェニル基又はナフチル基が挙げられ、これらはＣ_１〜Ｃ_４のアルコキシ基、Ｃ_１〜Ｃ_４のアルキル基またはハロゲン原子を置換基として含有してもよい。Ｒ_３及びＲ_４は共同で環を形成してもよい）
具体的には、アミノ基、ジエチルアミノ基、Ｎ−メチル−Ｎ−フェニルアミノ基、Ｎ，Ｎ−ジフェニルアミノ基、Ｎ，Ｎ−ジ（トリール）アミノ基、ジベンジルアミノ基、ピペリジノ基、モルホリノ基、ピロリジノ基等が挙げられる。
（７）メチレンジオキシ基、又はメチレンジチオ基等のアルキレンジオキシ基又はアルキレンジチオ基等が挙げられる。
（８）置換又は無置換のスチリル基、置換又は無置換のβ−フェニルスチリル基、ジフェニルアミノフェニル基、ジトリルアミノフェニル基等。

(In the formula, R ₃ and R ₄ each independently represent a hydrogen atom, an alkyl group defined in (2) above, or an aryl group. Examples of the aryl group include a phenyl group, a biphenyl group, and a naphthyl group. these may form a ring _C 1 -C ₄ alkoxy _groups, C 1 -C a alkyl group or a halogen atom ₄ which may contain as substituents .R ₃ and _{R 4} jointly)
Specifically, amino group, diethylamino group, N-methyl-N-phenylamino group, N, N-diphenylamino group, N, N-di (tolyl) amino group, dibenzylamino group, piperidino group, morpholino group And pyrrolidino group.
(7) An alkylenedioxy group or an alkylenedithio group such as a methylenedioxy group or a methylenedithio group.
(8) A substituted or unsubstituted styryl group, a substituted or unsubstituted β-phenylstyryl group, a diphenylaminophenyl group, a ditolylaminophenyl group, and the like.

The arylene group represented by Ar ₁ and Ar ₂ is a divalent group derived from the aryl group represented by Ar ₃ and Ar ₄ .

  X represents a single bond, a substituted or unsubstituted alkylene group, a substituted or unsubstituted cycloalkylene group, a substituted or unsubstituted alkylene ether group, an oxygen atom, a sulfur atom, or a vinylene group.

The substituted or unsubstituted alkylene group is a C ₁ -C ₁₂ , preferably C ₁ -C ₈ , more preferably C ₁ -C ₄ linear or branched alkylene group, and these alkylene groups include a fluorine atom, a hydroxyl group, a cyano _group, an alkoxy group of C 1 -C _4, a phenyl group or a halogen _atom, a phenyl group substituted with an alkyl group or a _C 1 -C ₄ alkoxy group C 1 -C ₄ It may be. Specifically, methylene group, ethylene group, n-butylene group, i-propylene group, t-butylene group, s-butylene group, n-propylene group, trifluoromethylene group, 2-hydroxyethylene group, 2-ethoxyethylene Group, 2-cyanoethylene group, 2-methoxyethylene group, benzylidene group, phenylethylene group, 4-chlorophenylethylene group, 4-methylphenylethylene group, 4-biphenylethylene group and the like.

The substituted or unsubstituted cycloalkylene _group, a cyclic alkylene group of C 5 -C _7, these are the cyclic alkylene group fluorine atom, a hydroxyl _group, an alkyl group of C 1 -C _4, a C 1 -C ₄ It may have an alkoxy group. Specific examples include a cyclohexylidene group, a cyclohexylene group, and a 3,3-dimethylcyclohexylidene group.

The substituted or unsubstituted alkylene ether group represents ethyleneoxy, propyleneoxy, ethylene glycol, propylene glycol, diethylene glycol, tetraethylene glycol, tripropylene glycol, alkylene ether group alkylene group is hydroxyl group, methyl group, ethyl group, etc. You may have the substituent of.
The vinylene group is

で表わされ、Ｒ_５は水素、アルキル基（前記（２）で定義されるアルキル基と同じ）、アリール基（前記Ａｒ_３、Ａｒ_４で表わされるアリール基と同じ）、ａは１または２、ｂは１〜３を表わす。

R ₅ is hydrogen, an alkyl group (same as the alkyl group defined in (2) above), an aryl group (same as the aryl group represented by Ar ₃ or Ar ₄ above), a is 1 or 2 , B represents 1-3.

Z represents a substituted or unsubstituted alkylene group, a substituted or unsubstituted alkylene ether divalent group, or an alkyleneoxycarbonyl divalent group.
Examples of the substituted or unsubstituted alkylene group include the same alkylene groups as those described above for X.
Examples of the substituted or unsubstituted alkylene ether divalent group include the divalent group of the alkylene ether group of X.
Examples of the alkyleneoxycarbonyl divalent group include a caprolactone-modified divalent group.

  Further, the radical polymerizable compound having a monofunctional charge transport structure of the present invention is more preferably a compound having a structure of the following general formula (3).

  (Wherein, o, p and q are each an integer of 0 or 1, Ra represents a hydrogen atom or a methyl group, Rb and Rc represent a substituent other than a hydrogen atom and an alkyl group having 1 to 6 carbon atoms, And s and t each represents an integer of 0 to 3. Za is a single bond, a methylene group, an ethylene group,

を表わす。）

Represents. )

  As the compound represented by the above general formula, a compound having a methyl group or an ethyl group as a substituent for Rb and Rc is particularly preferable.

  The radically polymerizable compound having a monofunctional charge transport structure represented by the general formulas (1) and (2), particularly (3) used in the present invention is polymerized with the carbon-carbon double bond open on both sides. Therefore, in a polymer that is not a terminal structure but is incorporated in a chain polymer and crosslinked by polymerization with a tri- or higher functional radical polymerizable monomer, it exists in the main chain of the polymer, and Present in the cross-linked chain between the chain and the main chain (this cross-linked chain has an intermolecular cross-linked chain between one polymer and another polymer, and a site where the main chain is folded in one polymer. And other intramolecular cross-linked chains that are cross-linked with other sites derived from the polymerized monomer at positions away from this in the main chain), but even if they are present in the main chain, Even if present, the triarylamine structure suspended from the chain moiety is It has at least three aryl groups arranged in the radial direction and is bulky, but is not directly bonded to the chain part, but is suspended from the chain part via a carbonyl group, etc. Since these triarylamine structures can be arranged adjacent to each other in the polymer, there is little structural distortion in the molecule, and the surface of the electrophotographic photosensitive member is also fixed. In the case of a layer, it is presumed that an intramolecular structure that is relatively free from interruption of the charge transport pathway can be adopted.

  Specific examples of the radically polymerizable compound having a monofunctional charge transporting structure of the present invention are shown below, but are not limited to the compounds having these structures.

  Further, the radical polymerizable compound having a monofunctional charge transport structure used in the present invention is important for imparting the charge transport performance of the crosslinked charge transport layer. -80% by weight, preferably 30-70% by weight. If this component is less than 20% by weight, the charge transport performance of the crosslinkable charge transport layer cannot be maintained sufficiently, and deterioration of electrical characteristics such as a decrease in sensitivity and an increase in residual potential will occur with repeated use. On the other hand, if it is 80% by weight or more, the content of the trifunctional monomer having no charge transport structure is lowered, and the crosslink density is lowered, so that high wear resistance is not exhibited. The electrical characteristics and abrasion resistance required differ depending on the process used, and the film thickness of the cross-linked charge transport layer of the photoreceptor varies accordingly. A range of 70% by weight is most preferred.

  The crosslinkable charge transport layer of the present invention is obtained by curing at least a trifunctional or higher radical polymerizable monomer having no charge transport structure and a radical polymerizable compound having a monofunctional charge transport structure. Monofunctional and bifunctional radically polymerizable monomers and radically polymerizable oligomers are used in combination for the purpose of imparting functions such as viscosity adjustment during coating, stress relaxation of the cross-linked charge transport layer, lower surface energy and reduced friction coefficient. be able to. Known radical polymerizable monomers and oligomers can be used.

  Examples of the monofunctional radical monomer include 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, tetrahydrofurfuryl acrylate, 2-ethylhexyl carbitol acrylate, 3-methoxybutyl acrylate, benzyl acrylate, and cyclohexyl acrylate. , Isoamyl acrylate, isobutyl acrylate, methoxytriethylene glycol acrylate, phenoxytetraethylene glycol acrylate, cetyl acrylate, isostearyl acrylate, stearyl acrylate, styrene monomer, and the like.

  Examples of the bifunctional radical polymerizable monomer include 1,3-butanediol diacrylate, 1,4-butanediol diacrylate, 1,4-butanediol dimethacrylate, 1,6-hexanediol diacrylate, 1, Examples include 6-hexanediol dimethacrylate, diethylene glycol diacrylate, neopentyl glycol diacrylate, bisphenol A-EO modified diacrylate, bisphenol F-EO modified diacrylate, neopentyl glycol diacrylate, and the like.

Examples of the functional monomer include those substituted with a fluorine atom such as octafluoropentyl acrylate, 2-perfluorooctylethyl acrylate, 2-perfluorooctylethyl methacrylate, 2-perfluoroisononylethyl acrylate, No. 60503, JP-B-6-45770, siloxane repeating units: 20-70 acryloyl polydimethylsiloxane ethyl, methacryloyl polydimethylsiloxane ethyl, acryloyl polydimethylsiloxane propyl, acryloyl polydimethylsiloxane butyl, diacryloyl polydimethylsiloxane Examples include vinyl monomers having a polysiloxane group such as diethyl, acrylates and methacrylates.
Examples of the radical polymerizable oligomer include epoxy acrylate, urethane acrylate, and polyester acrylate oligomers.

  However, if a large amount of monofunctional and bifunctional radically polymerizable monomers and radically polymerizable oligomers are contained, the three-dimensional crosslink density of the crosslinkable charge transport layer is substantially decreased, leading to a decrease in wear resistance. For this reason, the content of these monomers and oligomers is limited to 50 parts by weight or less, preferably 30 parts by weight or less, with respect to 100 parts by weight of the tri- or higher functional radical polymerizable monomer.

  The crosslinked charge transport layer of the present invention is obtained by curing at least a trifunctional or higher radical polymerizable monomer having no charge transport structure and a radical polymerizable compound having a monofunctional charge transport structure. Accordingly, a polymerization initiator may be contained in the crosslinking type charge transport layer coating solution in order to allow the curing reaction to proceed efficiently.

  Examples of the thermal polymerization initiator include 2,5-dimethylhexane-2,5-dihydroperoxide, dicumyl peroxide, benzoyl peroxide, t-butylcumyl peroxide, 2,5-dimethyl-2,5-di ( Peroxybenzoyl) hexyne-3, di-t-butyl peroxide, t-butyl hydroperoxide, cumene hydroperoxide, lauroyl peroxide, 2,2-bis (4,4-di-t-butylperoxycyclohexyl) B) Peroxide-based initiators such as propane, azo-based compounds such as azobisisobutylnitrile, azobiscyclohexanecarbonitrile, methyl azobisisobutyrate, azobisisobutylamidine hydrochloride, 4,4′-azobis-4-cyanovaleric acid Initiators are mentioned.

  Examples of the photopolymerization initiator include diethoxyacetophenone, 2,2-dimethoxy-1,2-diphenylethane-1-one, 1-hydroxy-cyclohexyl-phenyl-ketone, 4- (2-hydroxyethoxy) phenyl- (2 -Hydroxy-2-propyl) ketone, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) butanone-1, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 2- Acetophenone-based or ketal-based photopolymerization initiators such as methyl-2-morpholino (4-methylthiophenyl) propan-1-one, 1-phenyl-1,2-propanedione-2- (o-ethoxycarbonyl) oxime, Benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isobutyl ether Benzoin ether photopolymerization initiators such as benzoin isopropyl ether, benzophenone, 4-hydroxybenzophenone, methyl o-benzoylbenzoate, 2-benzoylnaphthalene, 4-benzoylbiphenyl, 4-benzoylphenyl ether, acrylated benzophenone, Benzophenone photopolymerization initiators such as 1,4-benzoylbenzene, thioxanthones such as 2-isopropylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2,4-dichlorothioxanthone Examples of photopolymerization initiators and other photopolymerization initiators include ethyl anthraquinone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2,4,6-trimethylbenzoic acid. Phenylethoxyphosphine oxide, bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide, bis (2,4-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide, methylphenylglyoxyester, 9,10 -Phenanthrene, an acridine type compound, a triazine type compound, an imidazole type compound is mentioned. Moreover, what has a photopolymerization acceleration effect can also be used individually or in combination with the said photoinitiator. Examples include triethanolamine, methyldiethanolamine, ethyl 4-dimethylaminobenzoate, isoamyl 4-dimethylaminobenzoate, (2-dimethylamino) ethyl benzoate, 4,4'-dimethylaminobenzophenone, and the like.

  These polymerization initiators may be used alone or in combination of two or more. The content of the polymerization initiator is 0.5 to 40 parts by weight, preferably 1 to 20 parts by weight with respect to 100 parts by weight of the total content having radical polymerizability.

  Furthermore, the crosslinkable charge transport layer coating liquid of the present invention is optionally provided with various plasticizers (added for the purpose of stress relaxation and adhesion improvement), leveling agents, and low molecular charge transport materials having no radical reactivity. Such additives can be contained. As these additives, known additives can be used, and as plasticizers, those used in general resins such as dibutyl phthalate and dioctyl phthalate can be used, and the amount used is the total solid content of the coating liquid. To 20 wt% or less, preferably 10 wt% or less. As leveling agents, silicone oils such as dimethyl silicone oil and methylphenyl silicone oil, polymers or oligomers having a perfluoroalkyl group in the side chain can be used, and the amount used is based on the total solid content of the coating liquid. 3% by weight or less is appropriate.

  The crosslinkable charge transport layer of the present invention will be described later with a coating liquid containing at least a trifunctional or higher-functional radical polymerizable monomer having no charge transport structure and a radical polymerizable compound having a monofunctional charge transport structure. It is formed by coating and curing on the charge transport layer. When the radically polymerizable monomer is a liquid, such a coating liquid can be applied by dissolving other components in the liquid, but if necessary, it is diluted with a solvent and applied.

  Solvents used at this time include alcohols such as methanol, ethanol, propanol and butanol, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone, esters such as ethyl acetate and butyl acetate, tetrahydrofuran, dioxane and propyl ether. And ethers such as dichloromethane, dichloroethane, trichloroethane and chlorobenzene, aromatics such as benzene, toluene and xylene, cellosolves such as methyl cellosolve, ethyl cellosolve and cellosolve acetate. These solvents may be used alone or in combination of two or more. The dilution ratio with the solvent varies depending on the solubility of the composition, the coating method, and the target film thickness, and is arbitrary. The coating can be performed using a dip coating method, spray coating, bead coating, ring coating method or the like.

  In the present invention, after applying such a crosslinkable charge transport layer coating solution, energy is applied from the outside and cured to form a crosslinkable charge transport layer. The external energy used at this time includes heat, light, and the like. , There is radiation. The heat energy is applied by heating from the coating surface side or the support side using a gas such as air or nitrogen, steam, various heat media, infrared rays, or electromagnetic waves. The heating temperature is preferably 100 ° C. or more and 170 ° C. or less, and if it is less than 100 ° C., the reaction rate is slow and the curing reaction is not completely completed. When the temperature is higher than 170 ° C., the curing reaction proceeds non-uniformly, and large strains, a large number of unreacted residues, and reaction termination terminals are generated in the cross-linked charge transport layer. In order to advance the curing reaction uniformly, it is also effective to complete the reaction by heating at a relatively low temperature of less than 100 ° C. and then heating to 100 ° C. or more.

As the energy of light, UV irradiation light sources such as high-pressure mercury lamps and metal halide lamps, which mainly have an emission wavelength in ultraviolet light, can be used, but a visible light source can also be selected according to the absorption wavelength of radically polymerizable substances and photopolymerization initiators. Is possible. Irradiation light amount is 50 mW / cm ² or more, preferably 1000 mW / cm ² or less, it takes time for the curing reaction is less than 50 mW / cm ^2. If it is higher than 1000 mW / cm ^2, the progress of the reaction becomes non-uniform, and local flaws are generated on the surface of the cross-linked charge transport layer, or many unreacted residues and reaction termination ends are generated. In addition, internal stress increases due to rapid crosslinking, which causes cracks and film peeling. Examples of radiation energy include those using electron beams. Among these energies, those using heat and light energy are useful because of the ease of reaction rate control and the simplicity of the apparatus.

  The film thickness of the crosslinked charge transport layer of the present invention is preferably 1 μm or more and 10 μm or less, more preferably 2 μm or more and 8 μm or less. If it is thicker than 10 μm, cracks and film peeling are likely to occur as described above, and if it is 8 μm or less, the margin is further improved, so that the crosslink density can be increased, and material selection and curing that further increases wear resistance. Conditions can be set. On the other hand, the radical polymerization reaction is prone to oxygen inhibition, that is, the surface in contact with the air is not easily cross-linked or non-uniform due to the effect of radical trapping by oxygen. This effect is noticeable when the surface layer is 1 μm or less, and the cross-linked charge transport layer having a thickness of less than this thickness is liable to cause a decrease in wear resistance or uneven wear. In addition, mixing of the lower layer charge transport layer component occurs during the application of the crosslinkable charge transport layer. If the coating thickness of the crosslinkable charge transport layer is thin, the contaminants spread throughout the layer, which inhibits the curing reaction and lowers the crosslink density. For these reasons, the cross-linked charge transport layer of the present invention has good wear resistance and scratch resistance at a film thickness of 1 μm or more, but when it is repeatedly used, it can be locally scraped to the lower charge transport layer. The wear of the portion increases, and the density unevenness of the halftone image tends to occur due to the chargeability and sensitivity fluctuation. Therefore, it is desirable that the thickness of the cross-linked charge transport layer be 2 μm or more for a longer life and higher image quality.

  In the present invention, the charge generation layer, the charge transport layer, and the crosslinkable charge transport layer are sequentially laminated. When the outermost crosslinkable charge transport layer is insoluble in the organic solvent, the wear resistance, scratch resistance, It is characterized by achieving sex. As a method for testing the solubility in an organic solvent, a drop of an organic solvent having high solubility in a polymer substance, for example, tetrahydrofuran, dichloromethane, or the like, is dropped on the surface layer of the photoconductor, and the surface shape of the photoconductor is dried after natural drying. It can be determined by observing the change with a stereomicroscope. Dissolving photoconductors have a phenomenon that the central part of the droplet becomes concave and the surroundings swell up, the charge transport material precipitates and becomes cloudy or cloudy due to crystallization, and the surface swells and then shrinks, causing wrinkles Changes such as phenomena are observed. In contrast, an insoluble photoconductor does not exhibit the above-described phenomenon, and does not change at all as before dropping.

  In the constitution of the present invention, in order to make the crosslinkable charge transport layer insoluble in the organic solvent, (1) composition of the crosslinkable charge transport layer coating solution, adjustment of the content ratio thereof, (2) crosslinkable charge Dilution solvent of transport layer coating solution, adjustment of solid content concentration, (3) Selection of coating method of crosslinkable charge transport layer, (4) Control of curing condition of crosslinkable charge transport layer, (5) Charge of lower layer It is important to control these, such as making the transport layer difficult to dissolve, but it is not achieved by a single factor.

  The composition of the crosslinkable charge transport layer coating liquid includes radical polymerization in addition to the above-described trifunctional or higher radical polymerizable monomer having no charge transport structure and a radical polymerizable compound having a monofunctional charge transport structure. When a large amount of additives such as binder resins, antioxidants, and plasticizers that do not have a functional functional group are included, the crosslinking density is reduced, the cured product resulting from the reaction and phase separation of the above additives occur, and the organic solvent Tend to be soluble. Specifically, it is important to suppress the total content to 20% by weight or less with respect to the total solid content of the coating liquid. Further, in order not to dilute the crosslinking density, the total content of monofunctional or bifunctional radical polymerizable monomers, reactive oligomers, and reactive polymers is 20% by weight or less based on the trifunctional radical polymerizable monomers. It is desirable.

  Further, when a large amount of a radical polymerizable compound having a bifunctional or higher functional charge transporting structure is contained, a bulky structure is fixed in the crosslinked structure by a plurality of bonds, so that distortion is likely to occur. It is easy to become an aggregate. This can cause solubility in organic solvents. Although different depending on the compound structure, the content of the radical polymerizable compound having a bifunctional or higher functional charge transporting structure is preferably 10% by weight or less based on the radical polymerizable compound having a monofunctional charge transporting structure.

  Regarding the diluting solvent of the crosslinkable charge transport layer coating solution, if a solvent with a low evaporation rate is used, the remaining solvent may interfere with curing or increase the amount of the lower layer component mixed, resulting in uneven curing. And the cured density is reduced. For this reason, it tends to be soluble in organic solvents. Specifically, tetrahydrofuran, a mixed solvent of tetrahydrofuran and methanol, ethyl acetate, methyl ethyl ketone, ethyl cellosolve and the like are useful, but are selected according to the coating method.

  Moreover, regarding the solid content concentration, if it is too low for the same reason, it tends to be soluble in an organic solvent. Conversely, the upper limit concentration is constrained by the limitations of film thickness and coating solution viscosity. Specifically, it is desirable to use in the range of 10 to 50% by weight. As the coating method for the cross-linked charge transport layer, for the same reason, the solvent content at the time of forming the coating film, the method of reducing the contact time with the solvent is preferable, specifically, the spray coating method, the amount of coating liquid A ring coat method in which the above is regulated is preferable. In order to suppress the amount of the lower layer component mixed, it is also effective to use a polymer charge transport material as the charge transport layer and to provide an insoluble intermediate layer for the coating solvent for the cross-linked charge transport layer.

  As curing conditions for the cross-linked charge transport layer, if the energy of heating or light irradiation is low, the curing is not completely completed and the solubility in the organic solvent is increased. On the other hand, when cured with very high energy, the curing reaction becomes non-uniform, and it tends to increase the number of uncrosslinked parts and radical stopping parts and to form an aggregate of minute cured products. For this reason, it may become soluble in an organic solvent. In order to insolubilize in an organic solvent, the heat curing conditions are preferably 100 to 170 ° C., 10 minutes to 3 hours, and the curing conditions by UV light irradiation are 50 to 1000 mW / cm 2, 5 seconds to 5 minutes, and It is desirable to control the temperature rise to 50 ° C. or less to suppress non-uniform curing reaction.

  In the structure of the present invention, an example of a method for making the crosslinkable charge transport layer insoluble in an organic solvent is, for example, an acrylate monomer having three acryloyloxy groups and a triaryl having one acryloyloxy group as a coating solution. In the case of using an amine compound, the ratio of use is 7: 3 to 3: 7, and a polymerization initiator is added in an amount of 3 to 20% by weight based on the total amount of these acrylate compounds, and a solvent is added to the coating solution. To prepare. For example, in the charge transport layer that is the lower layer of the cross-linked charge transport layer, when the surface layer is formed by spray coating using a triarylamine donor as the charge transport material and polycarbonate as the binder resin, the above coating is used. As the solvent of the liquid, tetrahydrofuran, 2-butanone, ethyl acetate and the like are preferable, and the use ratio is 3 to 10 times the total amount of the acrylate compound.

  Next, for example, the prepared coating solution is applied by spraying or the like on a photoreceptor in which an undercoat layer, a charge generation layer, and the charge transport layer are sequentially laminated on a support such as an aluminum cylinder. Thereafter, it is naturally dried or dried at a relatively low temperature for a short time (25 to 80 ° C., 1 to 10 minutes) and cured by UV irradiation or heating.

For UV irradiation, uses a metal halide lamp, illuminance 50 mW / cm ² or more, 1000 mW / cm ² or less, preferably about 5 minutes 5 seconds as the time, the drum temperature is controlled so as not to exceed 50 ° C. .
In the case of thermosetting, the heating temperature is preferably 100 to 170 ° C. For example, when a blowing oven is used as a heating means and the heating temperature is set to 150 ° C, the heating time is 20 minutes to 3 hours.
After completion of curing, the photosensitive member of the present invention is obtained by further heating at 100 to 150 ° C. for 10 to 30 minutes to reduce the residual solvent.

Next, the image forming apparatus of the present invention will be described in detail with reference to the drawings.
FIG. 3 is a schematic diagram for explaining the image forming process and the image forming apparatus of the present invention, and the following modifications also belong to the category of the present invention.
In FIG. 3, the photoreceptor (21) is an electrophotographic photoreceptor in which an undercoat layer containing a metal oxide and a binder resin and a photosensitive layer are laminated on a conductive support, and contains the metal oxide and the binder resin. The undercoat layer contains at least a copolymer having an amine value of 1 to 35 mgKOH / g, and the charge generation layer contains at least a phthalocyanine pigment. The photoreceptor (21) has a drum shape, but may be a sheet or endless belt. A charging roller (23), a pre-transfer charger (26), a transfer charger (29), a separation charger (30), and a pre-cleaning charger (32) include a corotron, a scorotron, a solid state charger, and charging. Known means such as a roller and a transfer roller are used.

  As a charging method, a corona discharge method represented by a conventionally known scorotron, a contact charging method in which a charging roller or a charging brush is brought into contact with the photosensitive member, and the photosensitive member and the charging member in the image forming region are 200 μm or less, preferably A proximity arrangement method (see FIG. 4) having a gap (gap) of 100 μm or less is preferably used. Such a charging method has a defect that dielectric breakdown of the photosensitive member is likely to occur because a high voltage is applied. However, the photosensitive member used in the present invention has a plurality of undercoat layers, and thus has a photosensitive layer. The body's pressure resistance is extremely high. For this reason, the photoconductor is highly resistant to dielectric breakdown, image quality deterioration due to dielectric breakdown is suppressed, and a longer life of the photoconductor is realized. Further, it is possible to superimpose an AC voltage on a DC voltage when a voltage is applied, which is effective in suppressing charging unevenness. In the present invention, any of the above known chargers can be used, but among these charging systems, the corona charging system represented by Scorotron is more preferable. The electrophotographic photosensitive member of the present invention realizes high durability by suppressing the first-round charge reduction that can be said to be a side effect of high sensitivity and scumming prevention, so that it is not necessary to replace the photosensitive member over a long period of time. Become. On the other hand, when a charging roller is used as the charging means, the charger is in contact with the surface of the photoconductor, so that the discharge product is likely to adhere to the surface of the photoconductor. In particular, a protective layer with high wear resistance is provided on the surface of the photoconductor. When formed, there is a risk of promoting the occurrence of abnormal images. Further, in the proximity-type charger, although the roller does not directly contact the photoconductor, the gap forming member is in contact with both ends of the photoconductor, which is slightly unsuitable for long-term repeated use at a high speed. The corona charging method is most preferably used because it is non-contact with the photoconductor and hardly damages the photoconductor even when the photoconductor rotates at high speed.

For the image exposure unit (24), a light source capable of ensuring high luminance such as a light emitting diode (LED), a semiconductor laser (LD), or electroluminescence (EL) is used.
Use light sources such as fluorescent lamps, tungsten lamps, halogen lamps, mercury lamps, sodium lamps, light-emitting diodes (LEDs), semiconductor lasers (LDs), and electroluminescence (ELs) as light sources such as static elimination lamps (22). Can do. Various types of filters such as a sharp cut filter, a band pass filter, a near infrared cut filter, a dichroic filter, an interference filter, and a color temperature conversion filter can be used to irradiate only light in a desired wavelength range. Among these light sources, light emitting diodes and semiconductor lasers have high irradiation energy, and have a long wavelength light of 600 to 800 nm. Therefore, the phthalocyanine pigment, which is the above-mentioned charge generation material, exhibits high sensitivity and is used well. The Such a light source or the like irradiates the photosensitive member with light by providing a transfer process, a static elimination process, a cleaning process, or a pre-exposure process using light irradiation in addition to the process shown in FIG.

  The toner developed on the photosensitive member (21) by the developing unit (25) is transferred to the transfer paper (28), but not all is transferred, and the toner remaining on the photosensitive member (21) is also transferred. Arise. Such toner is removed from the photoreceptor by the fur brush (33) and the blade (34). Cleaning may be performed only with a cleaning brush, and a known brush such as a fur brush or a mag fur brush is used as the cleaning brush.

When a positive (negative) charge is applied to the electrophotographic photosensitive member and image exposure is performed, a positive (negative) electrostatic latent image is formed on the surface of the photosensitive member. If this is developed with toner of negative (positive) polarity (detection fine particles), a positive image can be obtained, and if developed with toner of positive (negative) polarity, a negative image can be obtained. A known method is applied to the developing unit, and a known method is also used for the charge eliminating unit.
The above illustrated electrophotographic process is illustrative of an embodiment of the present invention, and of course other embodiments are possible.

The image forming means as described above may be fixedly incorporated in a copying apparatus, a facsimile, or a printer, but may be incorporated in these apparatuses in the form of a process cartridge. A process cartridge is a single device (part) that contains a photoconductor and further includes a charging unit, an exposure unit, a developing unit, a transfer unit, a cleaning unit, a neutralizing unit, and the like. There are many shapes and the like of the process cartridge, but a general example is shown in FIG. The photoreceptor is formed by laminating an undercoat layer, a photosensitive layer, and, if necessary, a protective layer on a conductive support.
In the process cartridge shown in FIG. 5, reference numeral (101) denotes a drum that rotates in the direction of an arrow, and there are a contact charging device (102), an image exposure (103) from an exposure device, and a developing device (104) around its periphery. ), A contact transfer device (106), a cleaning unit (107), and the like, and a transfer body (105) is supplied thereto.

FIG. 6 is a schematic diagram for explaining the tandem-type full-color electrophotographic apparatus of the present invention, and the following modifications also belong to the category of the present invention.
In FIG. 6, reference numerals (1C, 1M, 1Y, 1K) are drum-shaped photoconductors, and the photoconductor is the photoconductor of the present invention.

The photoreceptors (1C, 1M, 1Y, 1K) rotate in the direction of the arrow in the figure, and at least around them are charged members (2C, 2M, 2Y, 2K) and developing members (4C, 4M, 4Y, 4K). ), Cleaning members (5C, 5M, 5Y, 5K) are arranged. The charging members (2C, 2M, 2Y, 2K) are charging members that constitute a charging device for uniformly charging the surface of the photoreceptor.
Laser light (3C, 3M, 3Y, 3K) from an exposure member (not shown) from the back side of the photoreceptor between the charging member (2C, 2M, 2Y, 2K) and the developing member (4C, 4M, 4Y, 4K) , And an electrostatic latent image is formed on the photoreceptor (1C, 1M, 1Y, 1K).

  Then, four image forming elements (6C, 6M, 6Y, 6K) centering on such a photoreceptor (1C, 1M, 1Y, 1K) are along a transfer conveyance belt (10) which is a transfer material conveyance means. Are juxtaposed. The transfer / conveying belt (10) is provided between the developing member (4C, 4M, 4Y, 4K) and the cleaning member (5C, 5M, 5Y, 5K) of each image forming unit (6C, 6M, 6Y, 6K). 1C, 1M, 1Y, 1K), and a transfer brush (11C, 11M, 11Y, 11K) for applying a transfer bias to the back surface (back surface) of the transfer conveyance belt (10) that contacts the back side of the photoconductor. Is arranged. Each image forming element (6C, 6M, 6Y, 6K) is different in the color of the toner inside the developing device, and the others are the same in configuration.

  In the color electrophotographic apparatus having the configuration shown in FIG. 6, the image forming operation is performed as follows. First, in each image forming element (6C, 6M, 6Y, 6K), the charging member (2C, 2M, 2Y) in which the photoconductor (1C, 1M, 1Y, 1K) rotates in the direction of the arrow (the direction along with the photoconductor). , 2K), and then an electrostatic latent image corresponding to each color image to be created by laser light (3C, 3M, 3Y, 3K) by an exposure unit (not shown) disposed outside the photoconductor. It is formed.

  Next, the latent image is developed by the developing members (4C, 4M, 4Y, 4K) to form a toner image. The developing members (4C, 4M, 4Y, 4K) are developing members that perform development with toners of C (cyan), M (magenta), Y (yellow), and K (black), respectively. 1M, 1Y, and 1K) are overlaid on the transfer paper. The transfer paper (7) is fed out from the tray by the paper feed roller (8), temporarily stopped by the pair of registration rollers (9), and then transferred to the transfer conveyance belt (10) in synchronization with the image formation on the photosensitive member. Sent. The transfer paper (7) held on the transfer / conveying belt (10) is conveyed, and the toner images of the respective colors are transferred at the contact positions (transfer portions) with the respective photoreceptors (1C, 1M, 1Y, 1K). It is.

  The toner image on the photosensitive member is transferred onto the transfer paper (by the electric field formed by the potential difference between the transfer bias applied to the transfer brush (11C, 11M, 11Y, 11K) and the photosensitive member (1C, 1M, 1Y, 1K). 7) Transferred on top. Then, the recording paper (7) on which the toner images of four colors are superimposed through the four transfer portions is conveyed to the fixing device (12), where the toner is fixed, and is discharged to a paper discharge portion (not shown). Further, the residual toner remaining on the respective photoconductors (1C, 1M, 1Y, 1K) without being transferred by the transfer unit is collected by the cleaning device (5C, 5M, 5Y, 5K).

  In the example of FIG. 6, the image forming elements are arranged in the order of C (cyan), M (magenta), Y (yellow), and K (black) from the upstream side to the downstream side in the transfer paper conveyance direction. However, it is not limited to this order, and the color order is arbitrarily set. Further, when a black-only document is created, it is particularly effective to use the present invention to provide a mechanism for stopping the image forming elements (6C, 6M, 6Y) other than black.

  The image forming means as described above may be fixedly incorporated in a copying apparatus, facsimile, or printer, but each electrophotographic element may be incorporated in the apparatus in the form of a process cartridge. A process cartridge is a single device (part) that contains a photoconductor and further includes a charging unit, an exposure unit, a developing unit, a transfer unit, a cleaning unit, a neutralizing unit, and the like.

EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated, this invention is not restrict | limited by an Example. All parts are parts by weight.
First, a synthesis example of a compound having a monofunctional charge transport structure used in the present invention will be described.

<Synthesis example of compound having monofunctional charge transport structure>
The compound having a monofunctional charge transport structure in the present invention is synthesized, for example, by the method described in Japanese Patent No. 3164426. An example of this is shown below.
(1) Synthesis of hydroxy group-substituted triarylamine compound (the following structural formula B) 113.85 parts (0.3 mol) of a methoxy group-substituted triarylamine compound (the following structural formula A) and 138 parts of sodium iodide (0. 92 mol) was added 240 parts of sulfolane and heated to 60 ° C. in a nitrogen stream. In this liquid, 99 parts (0.91 mol) of trimethylchlorosilane was added dropwise over 1 hour and stirred at a temperature of about 60 ° C. for 4 and a half hours to complete the reaction. About 1500 parts of toluene was added to the reaction solution, cooled to room temperature, and washed repeatedly with water and an aqueous sodium carbonate solution. Thereafter, the solvent was removed from the toluene solution and purified by column chromatography (adsorption medium: silica gel, developing solvent: toluene: ethyl acetate = 20: 1). Cyclohexane was added to the obtained pale yellow oil to precipitate crystals. In this way, 88.1 parts (yield = 80.4%) of white crystals of the following structural formula B were obtained.
Its melting point was 64.0-66.0 ° C. Table 1 below shows the elemental analysis values.

(2) Triarylamino group-substituted acrylate compound (Exemplary Compound No. 54 in Table 1)
82.9 parts (0.227 mol) of the hydroxy group-substituted triarylamine compound (Structural Formula B) obtained in (1) above is dissolved in 400 parts of tetrahydrofuran, and an aqueous sodium hydroxide solution (NaOH: 12.2. 4 parts, water: 100 parts) was added dropwise. The solution was cooled to 5 ° C., and 25.2 parts (0.272 mol) of acrylic acid chloride was added dropwise over 40 minutes. Then, it stirred at 5 degreeC for 3 hours, and reaction was complete | finished. The reaction solution was poured into water and extracted with toluene. This extract was repeatedly washed with an aqueous sodium bicarbonate solution and water. Thereafter, the solvent was removed from the toluene solution and purified by column chromatography (adsorption medium: silica gel, developing solvent: toluene). N-Hexane was added to the obtained colorless oil to precipitate crystals. In this way, Exemplified Compound No. 54.73 parts of white crystals (yield = 84.8%) were obtained.
Its melting point was 117.5-119.0 ° C. The elemental analysis values are shown in Table 2 below.

Next, a method for producing an electrophotographic photoreceptor will be described.
<Example 1>
An undercoating layer 1 coating solution, an undercoating layer 2 coating solution, a charge generation layer coating solution, and a charge transport layer coating solution having the following composition are sequentially applied to an aluminum cylinder having a diameter of 100 mm and dried. An electrophotographic photosensitive member was prepared by laminating an undercoat layer 1 of .5 μm, an undercoat layer 2 of 3.5 μm, a charge generation layer, and a charge transport layer of 32 μm. This is referred to as an electrophotographic photoreceptor 1. After the coating of each layer, after touch drying, the undercoat layer 1 is heated at 130 ° C., the undercoat layer 2 is 140 ° C., the charge generation layer is 90 ° C., and the charge transport layer is heated at 135 ° C. for 20 minutes. Drying was performed.
(Coating liquid for undercoat layer 1)
N-methoxymethylated nylon (FR101: manufactured by Lead City) 5 parts Methanol 70 parts n-Butanol 30 parts (Coating liquid for undercoat layer 2)
Titanium oxide (CR-EL, purity: 99.7%, average primary particle size: about 0.25 μm,
Specific resistance: 3.5 × 10 ⁹ Ω · cm, manufactured by Ishihara Sangyo Co., Ltd.) 70 parts Copolymer (Disperbyk 2000, amine value of 1 to 35 mg KOH / g)
Amine value: 4 mg KOH / g, manufactured by BYK Chemie) 0.5 part Alkyd resin (Beckolite M6401-50, solid content: 50%,
Hydroxyl value: 130, manufactured by Dainippon Ink and Chemicals, Inc.) 16 parts Melamine resin (Super Becamine L145-60, solid content: 60%,
Dainippon Ink & Chemicals, Inc.) 10 parts 2-butanone 80 parts The volume ratio of the metal oxide to the binder resin is about 1.7 / 1. The weight ratio of the main agent and the curing agent is about 1.3 / 1.
(Coating solution for charge generation layer)
7 parts of titanyl phthalocyanine shown in XD spectrum of FIG. 7 Polyvinyl butyral (BX-1, manufactured by Sekisui Chemical Co., Ltd.) 5 parts 2-butanone 400 parts (coating liquid for charge transport layer)
Polycarbonate (TS2050, manufactured by Teijin Chemicals Ltd.) 10 parts Charge transport material of the following structural formula 7 parts

テトラヒドロフラン １００部
シリコーンオイルのテトラヒドロフラン溶液（ＫＦ−５０（１００ｃｓ）、
信越化学工業（株）製） ０．２部

Tetrahydrofuran 100 parts Silicone oil tetrahydrofuran solution (KF-50 (100 cs),
Shin-Etsu Chemical Co., Ltd.) 0.2 part

<Example 2>
An electrophotographic photosensitive member 2 was produced in the same manner as in Example 1 except that the copolymer contained in the coating solution for the undercoat layer 2 was changed to the following in Example 1.
A copolymer having an amine value of 1 to 35 mgKOH / g (Disperbyk2001,
Amine value: 29 mgKOH / g, manufactured by BYK Chemie) 0.3 parts

<Example 3>
An electrophotographic photosensitive member 3 was produced in the same manner as in Example 1 except that the copolymer contained in the coating solution for the undercoat layer 2 was changed to the following in Example 1.
A copolymer having an amine value of 1 to 35 mgKOH / g (Disperbyk161,
Amine value: 11 mgKOH / g, manufactured by BYK Chemie) 0.3 parts

<Example 4>
An electrophotographic photosensitive member 4 was produced in the same manner as in Example 1 except that the undercoat layer 2 coating solution in Example 1 was changed to a coating solution having the following composition.
(Coating liquid for undercoat layer 2)
Titanium oxide (CR-EL: Purity: 99.7%, average primary particle size: about 0.25 μm,
Specific resistance: 3.5 × 10 ⁹ Ω · cm, manufactured by Ishihara Sangyo Co., Ltd.) 65 parts Copolymer (Disperbyk2000, amine value of 1-35 mg KOH / g)
Amine value: 4 mg KOH / g, manufactured by BYK Chemie) 0.4 part Alkyd resin (Beckolite M6163-60, solid content: 60%,
Hydroxyl value: 70, manufactured by Dainippon Ink & Chemicals, Inc. 12 parts Blocked isocyanate compound (Bernock B3-867, solid content: 70%,
Dainippon Ink & Chemicals, Inc.) 10 parts 2-butanone 80 parts The volume ratio of metal oxide to binder resin is about 1.5 / 1. The weight ratio of the main agent and the curing agent is about 1/1.

<Example 5>
An electrophotographic photosensitive member 5 was produced in the same manner as in Example 1 except that the undercoat layer 2 coating solution in Example 1 was changed to a coating solution having the following composition.
(Coating liquid for undercoat layer 2)
Zinc oxide (SAZEX 2000, purity: 99.8%, average primary particle size: about 0.6 μm,
Specific resistance: 5.4 × 10 ⁷ Ω · cm, manufactured by Sakai Chemical Industry Co., Ltd.) 70 parts Copolymer (Disperbyk 2000, amine value of 1-35 mg KOH / g)
Amine value: 4 mg KOH / g, manufactured by BYK Chemie) 0.5 part Alkyd resin (Beckolite M6401-50, solid content: 50%,
Hydroxyl value: 130, manufactured by Dainippon Ink and Chemicals, Inc.) 20 parts Block isocyanate resin (Bernock B7-887-60, solid content: 60%,
Dainippon Ink & Chemicals, Inc.) 10 parts 2-butanone 80 parts The volume ratio of metal oxide to binder resin is about 1.5 / 1. The weight ratio of the main agent and the curing agent is about 1.7 / 1.

<Example 6>
In Example 1, an electrophotographic photosensitive member 6 was produced in the same manner as in Example 1 except that the undercoat layer 2 coating solution was changed to a coating solution having the following composition.
(Coating liquid for undercoat layer 2)
Titanium oxide (CR-EL: Purity: 99.7%, average primary particle size: about 0.25 μm,
Specific resistance: 3.5 × 10 ⁹ Ω · cm, manufactured by Ishihara Sangyo Co., Ltd.) 50 parts Titanium oxide (PT-401M, purity: 99.9%, average primary particle size: about 0.07 μm,
Specific resistance: 6.2 × 10 ⁷ Ω · cm, manufactured by Ishihara Sangyo Co., Ltd.) 30 parts A copolymer having an amine value of 1 to 35 mgKOH / g (Disperbyk2000,
Amine value: 4 mg KOH / g, manufactured by BYK Chemie) 0.5 part Alkyd resin (Beckolite M6401-50, solid content: 50%,
Hydroxyl value: 130, manufactured by Dainippon Ink & Chemicals, Inc.) 20 parts Melamine resin (Super Becamine L145-60, solid content: 60%,
Dainippon Ink & Chemicals, Inc.) 10 parts 2-butanone 100 parts The volume ratio of the metal oxide to the binder resin is about 1.7 / 1. The weight ratio of the main agent and the curing agent is about 1.7 / 1. D2 / D1 is 0.28, and the mixing ratio of metal oxide is about 0.38.

<Example 7>
An electrophotographic photoreceptor 7 was produced in the same manner as in Example 1 except that the undercoat layer 2 coating solution in Example 1 was changed to a coating solution having the following composition.
(Coating liquid for undercoat layer 2)
Titanium oxide (CR-EL: Purity: 99.7%, average primary particle size: about 0.25 μm,
Specific resistance: 3.5 × 10 ⁹ Ω · cm, manufactured by Ishihara Sangyo Co., Ltd.) 10 parts Titanium oxide (PT-401M, purity: 99.9%, average primary particle size: about 0.07 μm,
Specific resistance: 6.2 × 10 ⁷ Ω · cm, manufactured by Ishihara Sangyo Co., Ltd.) 70 parts Copolymer (Disperbyk 2000, amine value of 1-35 mg KOH / g)
Amine value: 4 mg KOH / g, manufactured by BYK Chemie) 0.6 parts Alkyd resin (Beckolite M6401-50, solid content: 50%,
Hydroxyl value: 130, manufactured by Dainippon Ink & Chemicals, Inc. 16 parts Blocked isocyanate resin (Bernock B7-887-60, solid content: 60%,
Dainippon Ink & Chemicals, Inc.) 15 parts 2-butanone 100 parts The volume ratio of the metal oxide to the binder resin is about 1.6 / 1. The weight ratio of the main agent and the curing agent is about 0.9 / 1. Further, D2 / D1 is 0.28, and the mixing ratio of the metal oxide is about 0.88.

<Example 8>
In Example 1, the electrophotographic photosensitive member 8 was prepared in the same manner as in Example 1 except that the coating liquid for the undercoat layer 2 was changed to the following composition and the film thickness of the undercoat layer 2 was changed to 12 μm. Produced.
(Coating liquid for undercoat layer 2)
Conductive titanium oxide (ET500W, average primary particle size: about 0.3 μm,
Specific resistance: 4.3 × 10 ² Ω · cm, manufactured by Ishihara Sangyo Co., Ltd.) 60 parts A copolymer having an amine value of 1 to 35 mgKOH / g (Disperbyk2000,
Amine value: 4 mg KOH / g, manufactured by BYK Chemie) 0.4 part Alkyd resin (Beckolite M6401-50, solid content: 50%,
Hydroxyl value: 130, manufactured by Dainippon Ink and Chemicals, Inc.) 16 parts Melamine resin (Super Becamine G821-60, solid content: 60%,
Dainippon Ink & Chemicals, Inc.) 7 parts 2-butanone 60 parts The volume ratio of the metal oxide to the binder resin is about 1.6 / 1. The weight ratio of the main agent and the curing agent is about 1.9 / 1.

<Example 9>
In Example 8, the coating solution for the undercoat layer 2 was applied on the conductive support, and the coating solution for the undercoat layer 1 was applied thereon. Thus, an electrophotographic photoreceptor 9 was produced.

<Example 10>
An electrophotographic photoreceptor 10 was produced in the same manner as in Example 1 except that the undercoat layer 2 coating solution in Example 1 was changed to a coating solution having the following composition.
(Coating liquid for undercoat layer 1)
Copolymer nylon (Amilan CM8000: manufactured by Toray) 5 parts Methanol 70 parts n-Butanol 30 parts

<Example 11>
An electrophotographic photosensitive member 11 was produced in the same manner as in Example 1 except that the thickness of the undercoat layer 1 was changed to 1.2 μm in Example 1.

<Example 12>
In Example 1, an electrophotographic photosensitive member 12 was produced in the same manner as in Example 1 except that the thickness of the undercoat layer 1 was changed to 2.1 μm.

<Example 13>
In Example 1, an electrophotographic photosensitive member 13 was produced in the same manner as in Example 1 except that the coating solution for the undercoat layer 1 was changed to one having the following composition.
(Coating liquid for undercoat layer 1)
Alkyd resin (Beckolite M6401-50, solid content: 50%,
Hydroxyl value: 130, manufactured by Dainippon Ink & Chemicals, Inc.) 4 parts Blocked isocyanate resin (Bernock B7-887-60, solid content: 60%,
Dainippon Ink & Chemicals, Inc.) 2 parts 2-butanone 120 parts

<Example 14>
In Example 1, an electrophotographic photosensitive member 14 was produced in the same manner as in Example 1 except that the undercoat layer 1 was not formed.

<Example 15>
An electrophotographic photosensitive member 15 was produced in the same manner as in Example 1 except that the undercoat layer 2 coating solution in Example 1 was changed to a coating solution having the following composition.
(Coating liquid for undercoat layer 2)
Titanium oxide (CR-EL, purity: 99.7%, average primary particle size: about 0.25 μm,
Specific resistance: 3.5 × 10 ⁹ Ω · cm, manufactured by Ishihara Sangyo Co., Ltd.) 70 parts Copolymer (Disperbyk 2000, amine value of 1 to 35 mg KOH / g)
Amine value: 4 mg KOH / g, manufactured by BYK Chemie) 0.07 parts Alkyd resin (Beckolite M6401-50, solid content: 50%,
Hydroxyl value: 130, manufactured by Dainippon Ink and Chemicals, Inc.) 16 parts Melamine resin (Super Becamine L145-60, solid content: 60%,
Dainippon Ink & Chemicals, Inc.) 10 parts 2-butanone 80 parts The volume ratio of the metal oxide to the binder resin is about 1.7 / 1. The weight ratio of the main agent and the curing agent is about 1.3 / 1.

<Example 16>
In Example 1, an electrophotographic photosensitive member 16 was produced in the same manner as in Example 1 except that the undercoat layer 2 coating solution was changed to a coating solution having the following composition.
(Coating liquid for undercoat layer 2)
Titanium oxide (CR-EL, purity: 99.7%, average primary particle size: about 0.25 μm,
Specific resistance: 3.5 × 10 ⁹ Ω · cm, manufactured by Ishihara Sangyo Co., Ltd.) 70 parts Copolymer (Disperbyk 2000, amine value of 1 to 35 mg KOH / g)
Amine value: 4 mg KOH / g, manufactured by BYK Chemie) 4.0 parts Alkyd resin (Beckolite M6401-50, solid content: 50%,
Hydroxyl value: 130, manufactured by Dainippon Ink and Chemicals, Inc.) 16 parts Melamine resin (Super Becamine L145-60, solid content: 60%,
Dainippon Ink & Chemicals, Inc.) 10 parts 2-butanone 80 parts The volume ratio of the metal oxide to the binder resin is about 1.7 / 1. The weight ratio of the main agent and the curing agent is about 1.3 / 1.

<Example 17>
In Example 15, an electrophotographic photosensitive member 17 was produced in the same manner as in Example 15 except that the undercoat layer 1 was not formed.

<Example 18>
An electrophotographic photosensitive member 18 was produced in the same manner as in Example 16 except that the undercoat layer 1 was not formed in Example 16.

<Example 19>
An electrophotographic photosensitive member 19 was produced in the same manner as in Example 1 except that the undercoat layer 2 coating solution in Example 1 was changed to a coating solution having the following composition.
(Coating liquid for undercoat layer 2)
Titanium oxide (CR-EL, purity: 99.7%, average primary particle size: about 0.25 μm,
Specific resistance: 3.5 × 10 ⁹ Ω · cm, manufactured by Ishihara Sangyo Co., Ltd.) 70 parts Copolymer (Disperbyk 2000, amine value of 1 to 35 mg KOH / g)
Amine value: 4 mg KOH / g, manufactured by BYK Chemie) 0.5 part Alkyd resin (Beckolite M6401-50, solid content: 50%,
Hydroxyl value: 130, manufactured by Dainippon Ink and Chemicals, Inc.) 16 parts Melamine resin (Super Becamine L145-60, solid content: 60%,
Dainippon Ink & Chemicals, Inc.) 10 parts Catalyst (n-dodecylbenzenesulfonic acid) 0.05 parts 2-butanone 80 parts The volume ratio of the metal oxide to the binder resin is about 1.7 / 1. The weight ratio of the main agent and the curing agent is about 1.3 / 1.

<Example 20>
In Example 4, an electrophotographic photosensitive member 20 was produced in the same manner as in Example 4 except that the undercoat layer 2 coating solution was changed to a coating solution having the following composition.
(Coating liquid for undercoat layer 2)
Titanium oxide (CR-EL: Purity: 99.7%, average primary particle size: about 0.25 μm,
Specific resistance: 3.5 × 10 ⁹ Ω · cm, manufactured by Ishihara Sangyo Co., Ltd.) 65 parts Copolymer (Disperbyk2000, amine value of 1-35 mg KOH / g)
Amine value: 4 mg KOH / g, manufactured by BYK Chemie) 0.4 part Alkyd resin (Beckolite M6163-60, solid content: 60%,
Hydroxyl value: 70, manufactured by Dainippon Ink & Chemicals, Inc. 12 parts Blocked isocyanate compound (Bernock B3-867, solid content: 70%,
Dainippon Ink & Chemicals, Inc.) 10 parts Catalyst (trioctylamine) 0.07 parts 2-butanone 80 parts The volume ratio of the metal oxide to the binder resin is about 1.5 / 1. The weight ratio of the main agent and the curing agent is about 1/1.

<Comparative Example 1>
An electrophotographic photosensitive member 21 was produced in the same manner as in Example 1 except that the undercoat layer 2 was not formed in Example 1.

<Comparative example 2>
An electrophotographic photosensitive member 22 was produced in the same manner as in Example 1 except that neither the undercoat layer 1 nor the undercoat layer 2 was formed in Example 1.

<Comparative Example 3>
In Example 1, the electrophotographic photosensitive member was the same as Example 1 except that the copolymer having an amine value of 1 to 35 mgKOH / g contained in the coating solution for the undercoat layer 2 was not added. 23 was produced.

<Comparative example 4>
In Example 14, the electrophotographic photosensitive member was the same as Comparative Example 1 except that the copolymer having an amine value of 1 to 35 mgKOH / g contained in the coating solution for the undercoat layer 2 was not added. 24 was produced.

<Comparative Example 5>
An electrophotographic photosensitive member 25 was produced in the same manner as in Example 1 except that the copolymer contained in the coating solution for the undercoat layer 2 was changed to the following in Example 1.
Instead of a copolymer having an amine value of 1 to 35 mg KOH / g (Disperbyk 103,
Amine value: 0 mg KOH / g, manufactured by BYK Chemie) 0.4 parts

<Comparative Example 6>
In Example 14, an electrophotographic photosensitive member 26 was produced in the same manner as in Example 1 except that the copolymer contained in the coating solution for the undercoat layer 2 was changed to the following.
Instead of a copolymer having an amine value of 1 to 35 mg KOH / g (Disperbyk 103,
Amine value: 0 mg KOH / g, manufactured by BYK Chemie) 0.4 parts

<Comparative Example 7>
In Example 1, an electrophotographic photosensitive member 27 was produced in the same manner as in Example 1 except that the copolymer contained in the coating solution for the undercoat layer 2 was changed to the following.
Instead of a copolymer having an amine value of 1 to 35 mg KOH / g (Disperbyk 112,
Amine value: 36 mgKOH / g, manufactured by BYK Chemie) 0.3 parts

<Comparative Example 8>
In Example 14, an electrophotographic photoreceptor 28 was produced in the same manner as in Example 1 except that the copolymer contained in the coating solution for the undercoat layer 2 was changed to the following.
Instead of a copolymer having an amine value of 1 to 35 mg KOH / g (Disperbyk 112,
Amine value: 36 mgKOH / g, manufactured by BYK Chemie) 0.3 parts

<Comparative Example 9>
In Example 1, an electrophotographic photosensitive member 29 was produced in the same manner as in Example 1 except that the coating liquid for the undercoat layer 2 was changed to the following composition.
(Coating liquid for undercoat layer 2)
Alkyd resin (Beckolite M6401-50, solid content: 50%,
Hydroxyl value: 130, manufactured by Dainippon Ink & Chemicals, Inc. 14 parts Blocked isocyanate resin (Bernock B7-887-60, solid content: 60%,
Dainippon Ink & Chemicals, Inc.) 8 parts 2-butanone 100 parts Metal oxide is not added. The weight ratio of the main agent to the curing agent is about 1.5 / 1.

<Comparative Example 10>
In Example 19, an electrophotographic photosensitive member 30 was produced in the same manner as in Example 1 except that the undercoat layer 2 coating solution was changed to a coating solution having the following composition.
(Coating liquid for undercoat layer 2)
Titanium oxide (CR-EL, purity: 99.7%, average primary particle size: about 0.25 μm,
Specific resistance: 3.5 × 10 ⁹ Ω · cm, manufactured by Ishihara Sangyo Co., Ltd.) 70 parts Copolymer (Disperbyk 2000, amine value of 1 to 35 mg KOH / g)
Amine value: 4 mg KOH / g, manufactured by BYK Chemie) 0.0 part Alkyd resin (Beckolite M6401-50, solid content: 50%,
Hydroxyl value: 130, manufactured by Dainippon Ink and Chemicals, Inc.) 16 parts Melamine resin (Super Becamine L145-60, solid content: 60%,
Dainippon Ink & Chemicals, Inc.) 10 parts Catalyst (n-dodecylbenzenesulfonic acid) 0.05 parts 2-butanone 80 parts The volume ratio of the metal oxide to the binder resin is about 1.7 / 1. The weight ratio of the main agent and the curing agent is about 1.3 / 1.

<Comparative Example 11>
In Example 20, an electrophotographic photosensitive member 31 was produced in the same manner as in Example 20 except that the undercoat layer 2 coating solution was changed to a coating solution having the following composition.
(Coating liquid for undercoat layer 2)
Titanium oxide (CR-EL: Purity: 99.7%, average primary particle size: about 0.25 μm,
Specific resistance: 3.5 × 10 ⁹ Ω · cm, manufactured by Ishihara Sangyo Co., Ltd.) 65 parts Copolymer (Disperbyk2000, amine value of 1-35 mg KOH / g)
Amine value: 4 mg KOH / g, manufactured by BYK Chemie) 0.0 part Alkyd resin (Beckolite M6163-60, solid content: 60%,
Hydroxyl value: 70, manufactured by Dainippon Ink & Chemicals, Inc. 12 parts Blocked isocyanate compound (Bernock B3-867, solid content: 70%,
Dainippon Ink & Chemicals, Inc.) 10 parts Catalyst (trioctylamine) 0.07 parts 2-butanone 80 parts The volume ratio of the metal oxide to the binder resin is about 1.5 / 1. The weight ratio of the main agent and the curing agent is about 1/1.

<Comparative Example 12>
In Example 14, an electrophotographic photoreceptor 32 was produced in the same manner as in Example 14 except that the charge generation layer coating solution was changed to a coating solution having the following composition.
(Coating solution for charge generation layer)
3 parts of trisazo pigment with the following structure

ポリビニルブチラール樹脂 １部
シクロヘキサノン １２０部
２−ブタノン ６０部

Polyvinyl butyral resin 1 part Cyclohexanone 120 parts 2-Butanone 60 parts

<Example 21>
In Example 1, the electrophotographic photosensitive member 33 was produced in the same manner as in Example 1 except that the coating liquid for the undercoat layer 1 was changed to a coating liquid having the following composition and the film thickness was changed to 1.0 μm. did.
(Coating liquid for undercoat layer 1)
Titanium oxide (CR-EL: Purity: 99.7%, average primary particle size: about 0.25 μm,
Specific resistance: 3.5 × 10 ⁹ Ω · cm, manufactured by Ishihara Sangyo Co., Ltd.) 40 parts N-methoxymethylated nylon (FR101: manufactured by Lead City) 10 parts Methanol 120 parts n-butanol 50 parts

<Example 22>
In Example 1, an electrophotographic photosensitive member 34 was produced in the same manner as in Example 1 except that the charge transport layer coating solution was changed to one having the following composition.
(Charge transport layer coating solution)
Methylene chloride 100 parts Silicone oil tetrahydrofuran solution (KF-50 (100 cs),
Shin-Etsu Chemical Co., Ltd.) 0.2 parts 15 parts of a polymer charge transport material having the following composition (weight average molecular weight: about 135,000)

<Example 23>
In Example 1, the thickness of the charge transport layer was changed to 25 μm, and a cross-linked charge transport layer having the following composition was formed on the charge transport layer. Was made. The film thickness of the crosslinked charge transport layer was 7 μm. The cross-linked charge transport layer is spray-coated and then air-dried for 20 minutes, followed by light irradiation under conditions of a metal halide lamp: 160 W / cm, irradiation intensity: 500 mW / cm ² , and irradiation time: 60 seconds. The film was cured. Thereafter, the crosslinked charge transport layer was dried by heating at 130 ° C.
(Coating liquid for crosslinkable charge transport layer)
10 parts of a tri- or more functional radical polymerizable monomer having no charge transporting structure (trimethylolpropane triacrylate (KAYARAD
TMPTA, manufactured by Nippon Kayaku) Molecular weight: 296, number of functional groups: trifunctional,
Molecular weight / number of functional groups = 99)
10 parts of a radically polymerizable compound having a monofunctional charge transporting structure (Exemplary Compound No. 54)
Photopolymerization initiator 1 part (1-hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184, manufactured by Ciba Specialty Chemicals))
Tetrahydrofuran 100 parts

<Example 24>
In Example 23, the radical polymerizable compound having a monofunctional charge transport structure is replaced with the following monomer instead of the trifunctional or higher radical polymerizable monomer having no charge transport structure, which is contained in the crosslinkable charge transport layer. Exemplified Compound No. Except for changing to 138 and 10 parts, an electrophotographic photosensitive member 36 was produced in the same manner as in Example 23.
Trifunctional or higher functional radical polymerizable monomer having no charge transporting structure 10 parts Pentaerythritol tetraacrylate (SR-295, manufactured by Kayaku Sartomer)
Molecular weight: 352, number of functional groups: 4 functions, molecular weight / number of functional groups = 88

<Example 25>
In Example 23, the trifunctional or higher functional radical polymerizable monomer having no charge transporting structure contained in the coating liquid for the crosslinkable charge transporting layer was changed to the following monomer, and the photopolymerization initiator was changed to the following compound 1 An electrophotographic photosensitive member 37 was produced in the same manner as in Example 23 except that the parts were changed.
Trifunctional or more radical polymerizable monomer having no charge transport structure 10 parts Caprolactone-modified dipentaerythritol hexaacrylate (KAYARAD DPCA-120, manufactured by Nippon Kayaku Co., Ltd.)
Molecular weight: 1947, number of functional groups: 6 functions, molecular weight / number of functional groups = 325

<Example 26>
Example 1 is the same as Example 1 except that the thickness of the charge transport layer is changed to 28 μm and a protective layer (metal oxide-containing charge transport layer) having the following composition is laminated on the charge transport layer. Thus, an electrophotographic photoreceptor 38 was produced. The film thickness of the metal oxide-containing charge transport layer was 5.0 μm. The protective layer was formed by spray coating, and dried at 150 ° C. for 20 minutes after coating.
(Coating liquid for metal oxide-containing charge transport layer)
Alumina (Sumicorundum AA-03, average primary particle size: 0.3 μm,
Sumitomo Chemical Co., Ltd.) 2 parts Wetting and dispersing agent (solid content 50%, BYK-P104, manufactured by BYK Chemie) 0.025 parts Polycarbonate (TS2050: manufactured by Teijin Chemicals Ltd.) 10 parts Charge transport of the following structural formula Substance 7 parts Cyclohexanone 500 parts Tetrahydrofuran 150 parts

<Comparative Example 13>
In Example 23, an electrophotographic photosensitive member was obtained in the same manner as in Example 23 except that the copolymer having an amine value of 1 to 35 mgKOH / g contained in the coating solution for the undercoat layer 2 was not added. 39 was produced.

[Examples 1 to 26, Comparative Examples 1 to 13]
The electrophotographic photoreceptors 1 to 39 produced as described above were mounted on a process cartridge and set in a digital copying machine manufactured by Ricoh Co., Ltd. The linear velocity of the photosensitive member in this image forming apparatus was 362 mm / sec. A scorotron was used as the charging member, and a 780 nm semiconductor laser (image writing using a polygon mirror) was used as the image exposure light source. The applied voltage is set so that the charging potential (VD) is 850 (−V), the developing bias is set to 600 (−V), and the dark portion potential (VD) of the first and third rounds of the photoreceptor in the initial stage is set. After the difference | ΔVD | and the exposed portion potential (VL) were measured, an image was output and image evaluation was performed. Thereafter, 800,000 sheets were run, and 10 minutes after the run was completed, the difference | ΔVD | in the dark portion potential (VD) between the first and third rounds of the photosensitive member and the exposure portion potential ( VL) was measured, and then an image was output 10 minutes after running 10,000 sheets, and the image was evaluated. The level of image evaluation was expressed in the following four stages.
A: Very good level B: Slight image quality degradation but no problem Δ: Level where image defects are clearly recognized ×: Image quality is greatly affected by image defects and the image quality is very bad.
These results are shown in Table 3.

  If the subbing layer containing the metal oxide and the binder resin does not contain a copolymer having an amine value of 1 to 35 mgKOH / g, the first-cycle charge reduction amount increases, and the first sheet after electrostatic fatigue There was a problem that soiling occurred. The tendency to increase the soil stain durability was improved by laminating an undercoat layer made of a resin layer that does not contain a metal oxide. The result was an increase in background contamination. In addition, if a copolymer having an amine value of 1 to 35 mgKOH / g is not contained, the soiling increases as a whole regardless of the presence or absence of a subbing layer containing no metal oxide, and the soiling durability is increased. There was also a tendency for sex to decline. When a copolymer having an amine value of 0 mgKOH / g was included, the potential at the exposed area was observed to decrease, but the amount of decrease in charge at the first round was increased and the background contamination was also increased. It was. In addition, when a copolymer having an amine value of 36 mgKOH / g was contained, a significant increase in the exposed area potential was observed. On the other hand, when a trisazo pigment was used instead of a titanyl phthalocyanine pigment in the charge generation layer, the phenomenon of charge reduction in the first round was not observed, but the sensitivity was insufficient and scumming occurred frequently, resulting in high sensitivity and durability. It was not possible to correspond to the high-speed machine that needed.

  In the present invention, the conductive support has an undercoat layer and a photosensitive layer containing at least a metal oxide and a binder resin, and the undercoat layer containing the metal oxide and the binder resin has at least an amine value. 1 to 35 mg KOH / g copolymer is contained, and at least the phthalocyanine pigment is contained in the photosensitive layer, thereby realizing both high sensitivity and stain resistance. It became possible to suppress the first-round charge drop, which was a side effect that had been observed when used. As a result, even when used repeatedly for a long period of time, not only improved durability of soiling is realized, but it is also possible to obtain a good image with little soiling from the first sheet, and at the same time high durability and high image quality It has become possible to obtain an image forming apparatus having high stability capable of stably outputting images at any time and capable of high-speed output. Furthermore, in the present invention, it is also possible to laminate an undercoat layer that does not contain a metal oxide, thereby realizing a significant improvement in dirt resistance without affecting the first round charge reduction. It was done. Further, it is possible to provide a protective layer on the surface of the photoreceptor, and in particular, by providing the cross-linked charge transport layer of the present invention, the effects of the first round charge reduction and background contamination can be sufficiently suppressed, and the photoreceptor A dramatic improvement in wear resistance has become possible, and higher durability has been achieved.

  The photoconductor of the present invention not only achieves both high sensitivity and stain resistance, but also can simultaneously suppress a decrease in charge in the first round of the photoconductor, which was a side effect of the photoconductor. An image forming apparatus using the same can stably output a high-quality image with little background contamination from the first sheet to a large number of sheets, and the effect is maintained even when used repeatedly for a long time. Accordingly, not only high durability and high stability of the image forming apparatus but also high speed and small size are realized, and the image forming apparatus can be effectively used for an image forming apparatus capable of high speed printing or full color printing.

It is sectional drawing which shows an example of the laminated constitution of the electrophotographic photoreceptor of this invention. It is a figure which shows the other example of a laminated constitution of the electrophotographic photoreceptor of this invention. It is the schematic for demonstrating the image formation process by the image forming apparatus of this invention. It is the schematic which shows a non-contact charging mechanism. It is a figure which shows an example of a structure of the process cartridge of this invention. 1 is a diagram illustrating an example of a configuration of a tandem full-color electrophotographic apparatus according to the present invention. 2 is an XD spectrum diagram of a titanyl phthalocyanine crystal used in Example 1. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Photoconductor 3 Charging roller 5 Image exposure part 7 Transfer paper 8 Feed roller 9 Registration roller 10 Transfer conveyance belt 12 Fixing device 15 Cleaning brush 16 Developing roller 17 Transfer roller 1C, 1M, 1Y, 1K Photoconductor 2C, 2M, 2Y 2K charging member 3C, 3M, 3Y, 3K laser beam 4C, 4M, 4Y, 4K developing member 5C, 5M, 5Y, 5K cleaning member 6C, 6M, 6Y, 6K image forming element 11C, 11M, 11Y, 11K transfer brush 21 Photoconductor 22 Static elimination lamp 23 Charging roller 24 Image exposure unit 25 Development unit 26 Pre-transfer charger 27 Registration roller 28 Transfer paper 29 Transfer charger 30 Separation charger 31 Separation claw 32 Pre-cleaning charger 33 Far brush 34 Cleaning blade 101 Drum 102 Contact charging Device 103 Image exposure 104 Developing device 105 Transfer body 106 Contact transfer device 107 Cleaning unit

Claims (44)

In an electrophotographic photoreceptor in which an undercoat layer containing at least a metal oxide and a binder resin and a photosensitive layer are sequentially laminated on a conductive support, the undercoat layer containing the metal oxide and the binder resin includes at least an amine. An electrophotographic photosensitive member comprising a copolymer having a valence of 1 to 35 mgKOH / g, wherein the photosensitive layer contains a phthalocyanine pigment. 2. The electrophotographic photosensitive member according to claim 1, wherein the photosensitive layer has a structure in which a charge generation layer and a charge transport layer are sequentially laminated. The phthalocyanine pigment is a titanyl phthalocyanine pigment having a maximum diffraction peak at 27.2 ° as a diffraction peak (± 0.2 °) of an X-ray diffraction spectrum with a Bragg angle 2θ with respect to CuKα rays (wavelength 1.542 mm). The electrophotographic photosensitive member according to claim 1, wherein the electrophotographic photosensitive member is provided. The electrophotographic photoreceptor according to claim 1, wherein the copolymer is a modified acrylic block copolymer. The electrophotographic photosensitive member according to any one of claims 1 to 4, wherein the content of the copolymer is 0.1 to 5.0 wt% with respect to the metal oxide. The electrophotographic photosensitive member according to claim 1, wherein the metal oxide has a specific resistance of 10 ⁷ Ω · cm or more. The electrophotographic photosensitive member according to claim 1, wherein the metal oxide is titanium oxide. The metal oxide is a mixture of two or more kinds of metal oxides having different average primary particle diameters, and the average primary particle diameter of the metal oxide having the largest average primary particle diameter is D1, and the smallest average primary particle diameter is The electrophotographic image according to any one of claims 1 to 7, wherein a relation of 0.2 <(D2 / D1) ≤0.5 is satisfied when an average primary particle diameter of the metal oxide is D2. Photoconductor. The electrophotographic photosensitive member according to claim 8, wherein the D2 is less than 0.2 μm. The mixing ratio of two or more metal oxides having different average primary particle sizes is T1, the content of the metal oxide having the largest average primary particle size, and the content of the metal oxide having the smallest average primary particle size The electrophotographic photosensitive member according to claim 8, wherein a relation of 0.2 ≦ T2 / (T1 + T2) ≦ 0.8 is satisfied in terms of a weight ratio when T2 is T2. The electrophotographic photosensitive member according to claim 1, wherein the binder resin is a thermosetting resin. The electrophotographic photoreceptor according to claim 11, wherein the thermosetting resin comprises an oil-free alkyd resin and a melamine resin. The electrophotographic photosensitive member according to claim 11, wherein the thermosetting resin comprises an oil-free alkyd resin and a blocked isocyanate compound. The electrophotographic photosensitive member according to claim 12 or 13, wherein the oil-free alkyd resin has a hydroxyl value of 60 or more. 15. The volume ratio of the metal oxide and the binder resin contained in the undercoat layer containing the metal oxide and the binder resin is in a range of 1/1 to 3/1. The electrophotographic photosensitive member according to any one of the above. The electrophotographic photosensitive member according to claim 11, wherein the undercoat layer containing the metal oxide and the binder resin further contains a catalyst. The electrophotographic photosensitive member according to claim 16, wherein the catalyst is at least one selected from an acid catalyst, an amine catalyst, and a metal compound catalyst. The electrophotographic photosensitive member according to claim 16 or 17, wherein the content of the catalyst is 0.01 to 5 wt% with respect to the binder resin. The electrophotographic photosensitive member according to claim 1, wherein the undercoat layer containing the metal oxide and the binder resin has a thickness of 1 μm or more and less than 10 μm. Between the conductive support and the undercoat layer containing the metal oxide and the binder resin, the undercoat layer does not contain a metal oxide, and the undercoat layer has a structure in which at least two layers are laminated. The electrophotographic photosensitive member according to claim 1, wherein: 21. The electrophotographic photosensitive member according to claim 20, wherein the undercoat layer not containing the metal oxide contains a polyamide resin. The electrophotographic photosensitive member according to claim 21, wherein the polyamide resin is N-methoxymethylated nylon. The electrophotographic photosensitive member according to any one of claims 20 to 22, wherein the undercoat layer not containing the metal oxide has a thickness of 0.1 µm or more and less than 2.0 µm. 24. The electrophotographic photosensitive member according to claim 1, further comprising a protective layer formed on the charge transport layer. The electrophotographic photosensitive member according to claim 24, wherein the protective layer comprises at least a metal oxide, a charge transport material, and a binder resin. 26. The electrophotographic photosensitive member according to claim 25, wherein the protective layer further contains a dispersant having an acid value. 25. The protective layer according to claim 24, wherein the protective layer is a crosslinked charge transport layer obtained by curing a radical polymerizable monomer having no charge transport structure and a radical polymerizable compound having a charge transport structure. Electrophotographic photoreceptor. The cross-linked charge transport layer is formed by curing a tri- or higher functional radical polymerizable monomer having no charge transport structure and a radical polymerizable compound having a monofunctional charge transport structure. The electrophotographic photosensitive member according to claim 27. 29. The electrophotographic photosensitive member according to claim 27 or 28, wherein the cross-linked charge transport layer is insoluble in an organic solvent. 30. The functional group of a tri- or higher functional radical polymerizable monomer having no charge transport structure used in the cross-linked charge transport layer is an acryloyloxy group and / or a methacryloyloxy group. The electrophotographic photosensitive member according to any one of the above. The ratio of the molecular weight to the number of functional groups (molecular weight / number of functional groups) in a trifunctional or higher functional radical polymerizable monomer having no charge transporting structure used for the crosslinkable charge transporting layer is 250 or less. The electrophotographic photosensitive member according to any one of 27 to 30. 32. The functional group of the radical polymerizable compound having a monofunctional charge transport structure used for the cross-linked charge transport layer is an acryloyloxy group or a methacryloyloxy group. The electrophotographic photosensitive member described. 33. The charge transport structure of the radical polymerizable compound having a monofunctional charge transport structure used for the cross-linked charge transport layer is a triarylamine structure. Electrophotographic photoreceptor. The radical polymerizable compound having a monofunctional charge transporting structure used in the cross-linked charge transporting layer is at least one compound represented by the following general formula (1) or (2). 34. The electrophotographic photosensitive member according to claim 27.

(In the formula, R ₁ represents a hydrogen atom, a halogen atom, an alkyl group which may have a substituent, an aralkyl group which may have a substituent, an aryl group which may have a substituent, a cyano group, a nitro group, Group, alkoxy group, —COOR ₇ (R ₇ is a hydrogen atom, an alkyl group which may have a substituent, an aralkyl group which may have a substituent or an aryl group which may have a substituent), halogen Carbonyl group or CONR ₈ R ₉ (R ₈ and R ₉ may have a hydrogen atom, a halogen atom, an alkyl group which may have a substituent, an aralkyl group which may have a substituent, or a substituent. Ar ₁ and Ar ₂ represent a substituted or unsubstituted arylene group, and may be the same or different.Ar ₃ , which may be the same or different from each other. Ar ₄ may be substituted Represents an unsubstituted aryl group, which may be the same or different, X represents a single bond, a substituted or unsubstituted alkylene group, a substituted or unsubstituted cycloalkylene group, a substituted or unsubstituted alkylene ether group, An oxygen atom, a sulfur atom, or a vinylene group, Z represents a substituted or unsubstituted alkylene group, a substituted or unsubstituted alkylene ether group, or an alkyleneoxycarbonyl group, and m and n represent an integer of 0 to 3.) 28. The radical polymerizable compound having a monofunctional charge transport structure used in the cross-linked charge transport layer is at least one compound represented by the following general formula (3). 34. The electrophotographic photosensitive member according to any one of 34.

(Wherein, o, p and q are each an integer of 0 or 1, Ra represents a hydrogen atom or a methyl group, Rb and Rc represent a substituent other than a hydrogen atom and an alkyl group having 1 to 6 carbon atoms, And s and t each represents an integer of 0 to 3. Za is a single bond, a methylene group, an ethylene group,

Represents. ) The proportion of the trifunctional or higher functional radical polymerizable monomer having no charge transporting structure used in the crosslinkable charge transport layer is 30 to 70% by weight based on the total amount of the crosslinkable charge transport layer. Item 36. The electrophotographic photosensitive member according to any one of Items 27 to 35. 28. The component ratio of the radical polymerizable compound having a monofunctional charge transporting structure used in the crosslinkable charge transport layer is 30 to 70% by weight based on the total amount of the crosslinkable charge transport layer. 37. The electrophotographic photoreceptor according to any one of items 36 to 36. 38. The electrophotographic photosensitive member according to claim 27, wherein the crosslinking type charge transport layer is cured by heating or light energy irradiation means. 39. An image forming apparatus comprising at least a charging unit, an exposing unit, a developing unit, a transfer unit, and an electrophotographic photosensitive member, wherein the electrophotographic photosensitive member is the electrophotographic photosensitive member according to any one of claims 1 to 38. An image forming apparatus, comprising: 40. The image forming apparatus according to claim 39, wherein a plurality of image forming elements comprising at least charging means, exposure means, developing means, transfer means, and electrophotographic photosensitive member are arranged. 41. The image forming apparatus according to claim 39, wherein a scorotron is used as a charging unit used in the image forming apparatus. 42. The image forming apparatus according to claim 39, wherein a linear velocity of the photosensitive member at the time of image formation is 300 mm / sec or more. The image forming apparatus includes a process cartridge for an image forming apparatus in which at least an electrophotographic photosensitive member and at least one means selected from a charging unit, an exposure unit, a developing unit, and a cleaning unit are integrated. 43. The image forming apparatus according to claim 39, wherein the process cartridge for the apparatus is detachable from the apparatus main body. An image forming apparatus process cartridge comprising at least an electrophotographic photosensitive member, wherein the electrophotographic photosensitive member is the electrophotographic photosensitive member according to any one of claims 1 to 38. .

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