JP2008046420A - Electrophotographic photoreceptor, process cartridge and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor which exhibits stable electric characteristics and can suppress occurrence of image defects such as fog, black spots and ghost even when repeatedly used. <P>SOLUTION: The electrophotographic photoreceptor comprises a conductive substrate 1, an undercoat layer 2 formed on the conductive substrate 1 and a photosensitive layer 3 formed on the undercoat layer 2, wherein the undercoat layer 2 contains metal oxide particles, an electron accepting material and an ionic material having the same basic skeleton as the electron accepting material. The ionic material is contained in the undercoat layer 2 in an amount of 5-15 mass% based on the total amount of the electron accepting material and the ionic material. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electrophotographic photosensitive member, a process cartridge, and an image forming apparatus.

  An electrophotographic image forming apparatus forms a uniform charge on an electrophotographic photosensitive member (hereinafter, abbreviated as “photosensitive member” in some cases) that is an image carrier, and then modulates an image signal with laser light or the like. After the electrostatic latent image is formed, the electrostatic latent image is developed with a charged toner to form a toner image, and the toner image is electrostatically applied to a recording medium such as paper directly or via an intermediate transfer member. By transferring, a desired transfer image is obtained.

  As an electrophotographic photoreceptor used in such an electrophotographic image forming apparatus, an organic photoreceptor using an organic material as a photoconductive material has become mainstream. Also, the constitution of the electrophotographic photosensitive member includes a layer containing a charge generating material (charge generating layer) and a charge transporting material from a single layer type photosensitive member having a layer containing both a charge generating material and a charge transporting material. The function-separated type photoconductor in which the layer (charge transport layer) to be separately provided is changed, and the performance of the electrophotographic photoconductor is improved.

  In such a function-separated type photoreceptor, an undercoat layer is often formed between the substrate and the photosensitive layer for the purpose of preventing charge injection from the substrate to the photosensitive layer. The characteristics of the photoreceptor, such as repeated stability and environmental stability, depend on the physical properties of the undercoat layer as well as the charge generation layer and charge transport layer. It is requested. Also, the subbing layer plays a major role in preventing image quality defects. In order to suppress image quality defects caused by substrate defects or stains, or upper layer coating film defects such as charge generation layers or coating film irregularities, It is very effective to provide a layer.

  Particularly in recent years, in image forming apparatuses, instead of non-contact charging devices such as corotrons, contact charging devices that generate less ozone are often used. When a local high electric field is applied to the locally deteriorated portion, an electrical pinhole is likely to be generated in the deteriorated portion, thereby causing image quality defects.

  In addition, this pinhole leak may occur due to a coating film defect of the photoreceptor itself, but otherwise, conductive foreign matter generated in the image forming apparatus contacts or penetrates into the photoreceptor, There may be a case where it becomes easier to form a conductive path between the contact charging device and the photoreceptor substrate. In a noticeable case, foreign matter mixed in from other members in the image forming apparatus or dust mixed in the image forming apparatus may pierce the photoconductor to form a leak point from the contact charging device.

  In order to remedy these problems, there has been a method of increasing the thickness of the undercoat layer to conceal defects in the base material and to contain conductive fine powder in the undercoat layer in order to stabilize electrical characteristics. Has been taken.

  As this method, two types of methods are mainly known. The first method is a method of forming a thick conductive layer in which conductive powder is dispersed on an aluminum substrate, and further forming an undercoat layer thereon. In this case, defects in the base material are concealed by a thick conductive layer, and the resistance of the conductive layer is adjusted to provide pinhole leak resistance. Further, the undercoat layer has a blocking (charge injection control) function. This method is advantageous in ensuring quality because the function of the undercoat layer is separated into two layers. In particular, the conductive layer has a merit that it is easy to obtain electrical stability because the resistance can be lowered within a range in which pinhole leakage resistance can be maintained by design.

The second method is to provide a thick undercoat layer with pinhole leak resistance and a blocking function at the interface between the undercoat layer and the photosensitive layer, thereby forming a single layer with the conductive layer. This is a method of forming a layer that also functions as a layer (for example, see Patent Document 1 below). According to this method, the number of stacked layers can be reduced by one as compared with the first method, so that the manufacturing facility and manufacturing process of the photoreceptor can be simplified, and the cost can be reduced. Therefore, in recent years, practical application of the second method has been actively studied.
Japanese Patent Application Laid-Open No. 8-14639

  However, in the second method, since the blocking function at the interface between the undercoat layer and the photosensitive layer may not be sufficiently secured, the blocking function at the interface is supplemented with bulk resistance by increasing the resistance of the undercoat layer. Sometimes. In this case, it is necessary to set the resistance of the undercoat layer to be high to some extent in design, so that problems such as electrical stability are likely to occur, electric characteristics are deteriorated during repeated use, and charge due to pinholes Insufficient leakage prevention is likely to cause image quality defects such as fogging and black spots.

  In order to improve the leakage prevention property, it is effective to increase the thickness of the undercoat layer. For example, a thickness of 10 μm or more is required. Defects are likely to occur. In particular, in recent years, development of an electrophotographic photosensitive member having a long life has been demanded due to an increase in awareness of environmental problems, and it is essential to improve the stability of electrical characteristics and image quality during repeated use over a long period of time.

  As described above, in the conventional electrophotographic photosensitive member, an undercoat layer that can sufficiently satisfy the characteristics required for the electrophotographic photosensitive member has not been obtained, and in particular, the stability of electrical characteristics during repeated use ( Cycle stability), fogging, sunspots, ghosts and the like have not been sufficiently solved.

  The present invention has been made in view of the above-described problems of the prior art, and exhibits stable electrical characteristics even when repeatedly used, and sufficiently suppresses image quality defects such as fogging, black spots, and ghosts. An object of the present invention is to provide an electrophotographic photosensitive member that can be used, a process cartridge and an image forming apparatus using the same.

  In order to achieve the above object, the present invention provides an electrophotographic photoreceptor comprising a conductive substrate, an undercoat layer formed on the conductive substrate, and a photosensitive layer formed on the undercoat layer. The undercoat layer contains metal oxide particles, an electron accepting material, and an ionic material having the same basic skeleton as the electron accepting material, and contains the ionic material in the undercoat layer. The electrophotographic photosensitive member is characterized in that the ratio is 5 to 15% by mass based on the total amount of the electron accepting substance and the ionic substance.

  According to such an electrophotographic photoreceptor, the undercoat layer contains metal oxide particles, an electron accepting substance, and an ionic substance having the same basic skeleton as the electron accepting substance, and the ionic substance in the undercoat layer When the content ratio is 5 to 15% by mass based on the total amount of the electron accepting substance and the ionic substance, the electrical connection between the electron accepting substance and the metal oxide particles is good through the ionic substance. Therefore, the electron injection property and the electron mobility are good in the interface between the undercoat layer and the upper layer (photosensitive layer, etc.) and in the undercoat layer bulk. As a result, the undercoat layer has excellent electrical stability, deterioration of electrical characteristics during repeated use, occurrence of image quality defects such as fog and black spots due to pinhole leaks, and image quality defects due to ghosting Can be sufficiently suppressed.

  Here, the ionic substance has the same basic skeleton as the electron accepting substance as long as it has substantially the same basic skeleton as the electron accepting substance, and is derived from the structure of the basic skeleton of the electron accepting substance. Including a structure having a basic structure as a basic skeleton.

  In addition, when the content ratio of the ionic substance in the undercoat layer is in the above range, it is possible to sufficiently suppress the deterioration of electrical characteristics and the occurrence of ghosts during repeated use. When the content ratio of the ionic substance is less than 5% by mass, the effect of improving the electron injection property and electron mobility of the undercoat layer becomes insufficient. On the other hand, when the content ratio of the ionic substance exceeds 15% by mass, the ionic substance becomes excessive and this impedes the electron injection property and the electron mobility as impurities. , Image quality defects due to ghosts occur. In particular, if the content ratio of the ionic substance is too large, the ionic substance is locally present in the undercoat layer and the electron mobility of the part becomes unsmooth. Image defects due to leaks and the like occur.

  In the electrophotographic photosensitive member of the present invention, the undercoat layer preferably contains a complex of metal oxide particles, an electron accepting substance, and an ionic substance. Usually, the bond between the electron accepting material and the metal oxide particles is not easily formed, and it is difficult to form a complex with these alone, but an ionic material having the same basic skeleton as the electron accepting material is not included in the system. In this case, the ionic substance mediates the reaction, the electron accepting substance and the metal oxide particles are easily bonded via the ionic substance, and a complex is easily formed. At this time, for example, the lipophilic part of the ionic substance reacts with the electron accepting substance, while the hydrophilic part of the ionic substance reacts with the metal oxide particles to form a complex. By including such a composite in the undercoat layer, the electron injection property and the electron mobility are extremely good in the interface between the undercoat layer and the upper layer and the undercoat layer bulk. In addition, the undercoat layer has excellent electrical stability, sufficiently deteriorates the electrical characteristics during repeated use, causes image defects such as fog and black spots due to pinhole leaks, and sufficiently generates image defects due to ghosting Can be suppressed.

  In the undercoat layer, the electron accepting substance is preferably present in the form of particles. Thereby, the contact between the electron accepting substance and the layer adjacent to the undercoat layer is more sufficiently secured, and the electron injection property and the electron mobility at the interface between the undercoat layer and the upper layer are improved. Furthermore, the size of the particles of the electron accepting material is preferably 10 μm or less. When the particle diameter exceeds 10 μm, image quality defects such as fogging and black spots tend to occur. The state of the electron accepting substance can be confirmed by, for example, observing the coating film with an SEM or an optical microscope when forming the undercoat layer.

  Furthermore, even when the undercoat layer having the above-described structure is thickened, deterioration of electrical characteristics during repeated use and generation of image quality defects such as ghosts are sufficiently suppressed. Therefore, according to the electrophotographic photosensitive member of the present invention, by increasing the thickness of the undercoat layer, foreign matter generated from a member in the image forming apparatus or dust entering from the outside of the image forming apparatus pierces the photosensitive member. Even so, the occurrence of leakage can be sufficiently prevented. Therefore, it is possible to obtain sufficiently good image quality over a long period of time.

  In the electrophotographic photosensitive member of the present invention, the electron accepting substance has an anthraquinone structure having a hydroxyl group as a basic skeleton, and the ionic substance has an anthraquinone structure as a basic skeleton. Is preferred. By using such a combination of an electron accepting material and an ionic material, the electrical connection between the electron accepting material and the metal oxide particles becomes better. In particular, the binding reaction between the electron accepting substance and the metal oxide particles proceeds smoothly via the ionic substance. As a result, the electrophotographic photosensitive member exhibits more stable electrical characteristics even when repeatedly used, and it is possible to sufficiently suppress the occurrence of image quality defects such as fogging, black spots, and ghosts.

  In the electrophotographic photoreceptor of the present invention, the ionic substance is preferably a sulfonate having an anthraquinone structure as a basic skeleton. When the ionic substance is a sulfonate, the binding reaction between the electron accepting substance and the metal oxide particles proceeds more smoothly via the ionic substance, and a complex is easily formed. As a result, the electrophotographic photosensitive member exhibits more stable electrical characteristics even when repeatedly used, and it is possible to sufficiently suppress the occurrence of image quality defects such as fogging, black spots, and ghosts.

  In the electrophotographic photoreceptor of the present invention, it is preferable that the metal oxide particles are surface-treated with a coupling agent. As a result, the electrophotographic photosensitive member exhibits more stable electrical characteristics even when used repeatedly, and it is possible to more sufficiently suppress the occurrence of image quality defects such as fogging, black spots, and ghosts. From the viewpoint of obtaining such effects more sufficiently, the coupling agent is preferably a silane coupling agent, and particularly preferably a silane coupling agent having an amino group.

  Furthermore, in the electrophotographic photoreceptor of the present invention, the metal oxide particles are preferably particles of at least one metal oxide selected from the group consisting of titanium oxide, zinc oxide, tin oxide and zirconium oxide. . By using these metal oxide particles, the leak resistance of the undercoat layer can be made more satisfactory.

  The present invention also provides the electrophotographic photosensitive member of the present invention, charging means for charging the electrophotographic photosensitive member, and developing the electrostatic latent image formed on the electrophotographic photosensitive member with toner to form a toner image. There is provided a process cartridge comprising: a developing unit for forming; and at least one selected from the group consisting of a cleaning unit for removing toner remaining on the surface of the electrophotographic photosensitive member.

  The present invention further includes the electrophotographic photosensitive member of the present invention, a charging unit for charging the electrophotographic photosensitive member, an exposure unit for forming an electrostatic latent image on the charged electrophotographic photosensitive member, And developing means for developing the electrostatic latent image with toner to form a toner image, and transfer means for transferring the toner image from the electrophotographic photosensitive member to a transfer target. An image forming apparatus is provided.

  According to the process cartridge and the image forming apparatus of the present invention, since the electrophotographic photosensitive member of the present invention having excellent characteristics as described above is used, it is possible to stably form an image with good image quality over a long period of time. Can do.

  According to the present invention, an electrophotographic photosensitive member that exhibits stable electrical characteristics even when repeatedly used and can sufficiently suppress the occurrence of image quality defects due to fogging, black spots, and ghosts, and a process using the same A cartridge and an image forming apparatus can be provided.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In the following description, the same or corresponding parts are denoted by the same reference numerals, and redundant description is omitted.

(Electrophotographic photoreceptor)
FIG. 1 is a schematic cross-sectional view showing a preferred embodiment of the electrophotographic photosensitive member of the present invention. As shown in FIG. 1, the electrophotographic photoreceptor 100 has a structure in which an undercoat layer 2, an intermediate layer 4, a photosensitive layer 3, and a protective layer 5 are sequentially laminated on a conductive substrate 1. The electrophotographic photoreceptor 100 shown in FIG. 1 is a function-separated type photoreceptor, and the photosensitive layer 3 includes a charge generation layer 31 and a charge transport layer 32. The undercoat layer 2 is a layer containing metal oxide particles, an electron accepting substance, and an ionic substance having the same basic skeleton as the electron accepting substance. The content ratio is 5 to 15% by mass based on the total amount of the electron accepting substance and the ionic substance. Hereinafter, each element will be described based on the electrophotographic photoreceptor 100 shown in FIG.

  Examples of the conductive substrate 1 include metal drums such as aluminum, copper, iron, stainless steel, zinc, and nickel; aluminum, copper, gold, silver, platinum, palladium, and the like on a substrate such as a sheet, paper, plastic, and glass. Deposited metal such as titanium, nickel-chromium, stainless steel, copper, indium, etc. or deposited conductive metal compound such as indium oxide and tin oxide; laminated metal foil on the base material or carbon black, Indium oxide, tin oxide, antimony oxide powder, metal powder, copper iodide and the like are dispersed in a binder resin and subjected to a conductive treatment by coating it.

  The shape of the conductive substrate 1 is not limited to a drum shape, and may be a sheet shape or a plate shape. When the conductive substrate 1 is a metal pipe, the surface thereof may be left as it is, or a treatment such as mirror cutting, etching, anodizing, rough cutting, centerless grinding, sand blasting, wet honing, etc. in advance. May be performed.

  The undercoat layer 2 is a layer containing metal oxide particles, an electron accepting material, and an ionic material having the same basic skeleton as the electron accepting material.

The metal oxide particles preferably have a powder resistance (volume resistivity) of about 1 × 10 ² to 1 × 10 ¹¹ Ω · cm. By using such metal oxide particles, the undercoat layer 2 can obtain an appropriate resistance for obtaining leak resistance. If the resistance value of the metal oxide particles is lower than the lower limit of the above range, sufficient leakage resistance is difficult to obtain, whereas if it is higher than the upper limit of this range, the residual potential tends to increase.

  As the metal oxide particles, it is preferable to use metal oxide particles such as tin oxide, titanium oxide, zinc oxide, and zirconium oxide having the above resistance values. Among these, zinc oxide is particularly preferably used. Further, two or more kinds of metal oxide particles having different surface treatments or different particle diameters can be used in combination.

As the metal oxide particles, those having a specific surface area of 10 m ² / g or more are preferably used. Those having a specific surface area value of 10 m ² / g or less tend to cause a decrease in chargeability and tend to make it difficult to obtain good electrophotographic characteristics.

  The metal oxide particles can be subjected to a surface treatment. The surface treatment agent is not particularly limited as long as the desired properties can be obtained, and can be selected from known materials. For example, a silane coupling agent, a titanate coupling agent, an aluminum coupling agent, a surfactant, and the like can be given. In particular, silane coupling agents are preferably used because they give good electrophotographic characteristics. Furthermore, a silane coupling agent having an amino group is preferably used because it gives a good blocking property to the undercoat layer 2.

  Any silane coupling agent having an amino group can be used as long as it can obtain desired photoreceptor characteristics, and is not particularly limited. Specific examples include γ-aminopropyltriethoxysilane, N- β- (aminoethyl) -γ-aminopropyltrimethoxysilane, N-β- (aminoethyl) -γ-aminopropylmethylmethoxysilane, N, N-bis (β-hydroxyethyl) -γ-aminopropyltriethoxy Silane etc. are mentioned.

  Moreover, 2 or more types of silane coupling agents can also be mixed and used. Examples of the silane coupling agent that can be used in combination with the above silane coupling agent having an amino group include vinyltrimethoxysilane, γ-methacryloxypropyl-tris (β-methoxyethoxy) silane, β- (3 , 4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, vinyltriacetoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-β- (aminoethyl) -Γ-aminopropyltrimethoxysilane, N-β- (aminoethyl) -γ-aminopropylmethylmethoxysilane, N, N-bis (β-hydroxyethyl) -γ-aminopropyltriethoxysilane, γ-chloropropyl Examples include trimethoxysilane, The present invention is not limited to these.

  As the surface treatment method, any known method can be used. For example, a dry method or a wet method can be used.

  When surface treatment is performed by the dry method, the silane coupling agent is added directly or dissolved in an organic solvent while stirring the metal oxide particles with a mixer having a large shearing force, etc. together with dry air or nitrogen gas. It is uniformly processed by spraying. When adding or spraying a silane coupling agent, it is preferable to carry out at the temperature below the boiling point of a solvent. Spraying at a temperature equal to or higher than the boiling point of the solvent is not preferable because the solvent evaporates before being uniformly stirred, and the silane coupling agent is locally concentrated, making it difficult to perform uniform processing. After adding or spraying the silane coupling agent, baking can be performed at 100 ° C. or higher. Baking can be carried out in an arbitrary range as long as the temperature and time allow the desired electrophotographic characteristics to be obtained.

  As a wet method, metal oxide particles are stirred in a solvent, dispersed using ultrasonic waves, a sand mill, an attritor, a ball mill, etc., and a silane coupling agent solution is added thereto and stirred or dispersed. It is processed uniformly by removing. As a method for removing the solvent, a method of distilling off by filtration or distillation is used. After removing the solvent, baking can be performed at 100 ° C. or higher. Baking can be carried out in an arbitrary range as long as the temperature and time allow the desired electrophotographic characteristics to be obtained. In the wet method, the moisture contained in the metal oxide particles can be removed before adding the surface treatment agent. For example, the method of removing with stirring and heating in the solvent used for the surface treatment, and the solvent. A method of removing by boiling can be used.

  The amount of the silane coupling agent relative to the metal oxide particles in the undercoat layer 2 can be arbitrarily set as long as desired electrophotographic characteristics can be obtained.

  As the electron-accepting substance, any substance can be used as long as the desired characteristics can be obtained, but those having a group capable of reacting with metal oxide particles or ionic substances are preferably used, and compounds having a hydroxyl group Is more preferably used. In particular, an acceptor compound having an anthraquinone structure having a hydroxyl group as a basic skeleton is preferably used. Examples of the compound having an anthraquinone structure having a hydroxyl group as a basic skeleton include hydroxyanthraquinone compounds and aminohydroxyanthraquinone compounds, and any of them can be preferably used. More specifically, as the electron accepting substance, alizarin, quinizarin, anthralphine, purpurin, 1-hydroxyanthraquinone, 2-amino-3-hydroxyanthraquinone, 1-amino-4-hydroxyanthraquinone and the like are particularly preferably used.

  The electron accepting material is preferably in the form of particles. As a result, contact between the electron-accepting material and the layer adjacent to the undercoat layer 2 (intermediate layer 4 in the electrophotographic photosensitive member 100) is more sufficiently secured, and the undercoat layer 2 and the intermediate layer 4 as an upper layer thereof The electron injection property and the electron mobility at the interface of the film become better. Furthermore, the size of the particles of the electron accepting material is preferably 10 μm or less. When the particle diameter exceeds 10 μm, image quality defects such as fogging and black spots tend to occur.

  As the ionic substance, those having the same basic skeleton as the electron accepting substance are used. As the ionic substance, any substance can be used as long as the desired characteristics can be obtained. As the ionic substance, an electron-accepting substance having an anthraquinone structure having a hydroxyl group as a basic skeleton is used. Those having an anthraquinone structure as a basic skeleton are preferably used. Further, as the ionic compound, sulfonate, nitrate, carbonate, phosphate and the like are preferably used, and sulfonate having an anthraquinone structure as a basic skeleton is particularly preferably used. Although it does not restrict | limit especially as a positive component of these salts, For example, an alkali metal, alkaline-earth metal, an amine, etc. are mentioned.

  In the undercoat layer 2, the content ratio of the electron accepting substance and the ionic substance is 85 to 95% by mass based on the total amount of the electron accepting substance and the ionic substance. The content rate of an ionic substance is 5-15 mass%. When the content ratio of the ionic substance is less than 5% by mass, the effect of improving the electron injection property and the electron mobility of the undercoat layer 2 becomes insufficient. On the other hand, when the content ratio of the ionic substance exceeds 15% by mass, the excessive ionic substance inhibits the electron injection property and the electron mobility, and the electrical characteristics are deteriorated during repeated use, and the image quality defect due to the ghost. Occurs. In particular, if the content ratio of the ionic substance is too large, the ionic substance is locally present in the undercoat layer 2 and the electron mobility of the part is not smooth. Image defects such as dots and leaks occur.

  From the viewpoint of obtaining the effect of the present invention more sufficiently, the content ratio of the ionic substance is preferably 5 to 10% by mass based on the total amount of the electron accepting substance and the ionic substance.

  In the undercoat layer 2, the metal oxide particles, the electron accepting substance, and the ionic substance may each exist alone, but at least some of them are bonded to each other to form a composite. Preferably it is. Note that the metal oxide particles, the electron-accepting substance, and the ionic substance may form a composite in any combination. Further, for example, a composite composed only of metal oxide particles and an electron accepting substance may be included. Since the metal oxide particles, the electron accepting substance and the ionic substance form a composite, the electron injection property and electron mobility of the undercoat layer 2 become extremely good, and the undercoat layer 2 has excellent electrical properties. Stability can be obtained, and it is possible to sufficiently suppress the deterioration of electrical characteristics during repeated use, the occurrence of image quality defects such as fog and black spots due to pinhole leaks, and the occurrence of image quality defects due to ghosting. Become.

  The method for obtaining the complex of the metal oxide particles, the electron accepting substance and the ionic substance is not particularly limited. For example, after reacting the electron accepting substance and the ionic substance in a solvent in which both are dissolved, the metal oxidation is performed. A composite can be formed by mixing physical particles.

  The amount of the electron-accepting substance applied can be arbitrarily set as long as desired characteristics are obtained, but is preferably 0.01 to 20 parts by mass with respect to 100 parts by mass of the metal oxide particles. More preferably, it is 05-10 mass parts. If the amount of the electron-accepting substance applied is less than 0.01 parts by mass, sufficient electron-accepting property that contributes to improvement of charge accumulation in the undercoat layer 2 cannot be imparted, so that the increase in residual potential is sufficiently suppressed during repeated use It becomes difficult to obtain the effect. Further, if it exceeds 20 parts by mass, the metal oxide particles are likely to aggregate, and it becomes difficult for the metal oxide particles to form a good conductive path in the undercoat layer 2 when the undercoat layer 2 is formed. Not only does it easily deteriorate the sustainability such as an increase in residual potential during use, but it also easily causes image quality defects such as black spots.

  As the binder resin contained in the undercoat layer 2, any known resin can be used as long as it can form a good film and can obtain desired characteristics. For example, acetal such as polyvinyl butyral can be used. Resin, polyvinyl alcohol resin, casein, polyamide resin, cellulose resin, gelatin, polyurethane resin, polyester resin, methacrylic resin, acrylic resin, polyvinyl chloride resin, polyvinyl acetate resin, vinyl chloride-vinyl acetate-maleic anhydride resin, silicone resin , Using known polymer resin compounds such as silicone-alkyd resin, phenol resin, phenol-formaldehyde resin, melamine resin, urethane resin, charge transport resin having a charge transport group, or conductive resin such as polyaniline, etc. Can do. Of these, resins insoluble in the upper coating solvent are preferably used, and phenol resins, phenol-formaldehyde resins, melamine resins, urethane resins, epoxy resins, and the like are particularly preferably used.

  The undercoat layer 2 can be formed using an undercoat layer forming coating solution obtained by dispersing each component constituting the above undercoat layer in a solvent. In addition, the compounding ratio (mass ratio) of the metal oxide particles and the binder resin in the coating liquid for forming the undercoat layer can be arbitrarily set within a range where desired electrophotographic photoreceptor characteristics can be obtained, but 5: 1 to 1: 5 is preferable. Moreover, it is preferable that the compounding ratio (mass ratio) of the metal oxide particles and the electron accepting substance in the coating solution for forming the undercoat layer is 2: 1 to 1: 2.

  Various additives can be used in the coating liquid for forming the undercoat layer in order to improve electrical characteristics, environmental stability, and image quality. As additives, quinone compounds such as chloranil and bromoanil, tetracyanoquinodimethane compounds, fluorenone compounds such as 2,4,7-trinitrofluorenone, 2,4,5,7-tetranitro-9-fluorenone, 2- (4-biphenyl) -5- (4-t-butylphenyl) -1,3,4-oxadiazole, 2,5-bis (4-naphthyl) -1,3,4-oxadiazole, Oxadiazole compounds such as 2,5-bis (4-diethylaminophenyl) -1,3,4-oxadiazole, xanthone compounds, thiophene compounds, 3,3 ′, 5,5 ′ tetra-t-butyl Electron transporting substances such as diphenoquinone compounds such as diphenoquinone, electron transporting pigments such as polycyclic condensation systems and azo systems, zirconium chelate compounds, titanium chelation Things, aluminum chelate compounds, titanium alkoxide compounds, organic titanium compounds, there can be used a known material such as a silane coupling agent.

  The silane coupling agent is used for the surface treatment of the metal oxide particles, but it can also be used as an additive added to the coating solution. Specific examples of the silane coupling agent used here include vinyltrimethoxysilane, γ-methacryloxypropyl-tris (β-methoxyethoxy) silane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ. -Glycidoxypropyltrimethoxysilane, vinyltriacetoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-β- (aminoethyl) -γ-aminopropyltrimethoxysilane, N-β -(Aminoethyl) -γ-aminopropylmethylmethoxysilane, N, N-bis (β-hydroxyethyl) -γ-aminopropyltriethoxysilane, γ-chloropropyltrimethoxysilane and the like.

  Examples of zirconium chelate compounds include zirconium butoxide, zirconium zirconium acetoacetate, zirconium triethanolamine, acetylacetonate zirconium butoxide, ethyl acetoacetate butoxide, zirconium acetate, zirconium oxalate, zirconium lactate, zirconium phosphonate, zirconium octoate, Zirconium naphthenate, zirconium laurate, zirconium stearate, zirconium isostearate, methacrylate zirconium butoxide, stearate zirconium butoxide, isostearate zirconium butoxide and the like.

  Examples of titanium chelate compounds include tetraisopropyl titanate, tetranormal butyl titanate, butyl titanate dimer, tetra (2-ethylhexyl) titanate, titanium acetylacetonate, polytitanium acetylacetonate, titanium octylene glycolate, titanium lactate ammonium salt , Titanium lactate, titanium lactate ethyl ester, titanium triethanolamate, polyhydroxy titanium stearate and the like.

  Examples of the aluminum chelate compound include aluminum isopropylate, monobutoxy aluminum diisopropylate, aluminum butyrate, diethyl acetoacetate aluminum diisopropylate, aluminum tris (ethyl acetoacetate) and the like.

  These compounds can be used alone or as a mixture or polycondensate of a plurality of compounds.

  As a solvent for adjusting the coating liquid for forming the undercoat layer, any known organic solvent such as alcohol, aromatic, halogenated hydrocarbon, ketone, ketone alcohol, ether, ester, etc. Can be selected. More specifically, for example, methanol, ethanol, n-propanol, iso-propanol, n-butanol, benzyl alcohol, methyl cellosolve, ethyl cellosolve, acetone, methyl ethyl ketone, cyclohexanone, methyl acetate, ethyl acetate, n-acetate Usual organic solvents such as butyl, dioxane, tetrahydrofuran, methylene chloride, chloroform, chlorobenzene, and toluene can be used. These solvents can be used alone or in admixture of two or more. When two or more types are mixed and used, any combination can be used as long as the solvent can dissolve the binder resin as a mixed solvent.

  Further, as described above, it is important to mix a solvent having low solubility of the electron accepting substance from the viewpoint of leaving the electron accepting substance in the form of particles. Since electron acceptors are generally highly polar, their solubility in nonpolar solvents is often low. As the nonpolar solvent, a hydrocarbon solvent is generally used, and examples thereof include hexane, octane, and cyclohexane.

  As a method for dispersing the metal oxide particles, the electron accepting substance, and the ionic substance, known methods such as a roll mill, a ball mill, a vibrating ball mill, an attritor, a sand mill, a colloid mill, and a paint shaker can be used.

  As a coating method for the coating solution for forming the undercoat layer, a normal method such as a blade coating method, a wire bar coating method, a spray coating method, a dip coating method, a bead coating method, an air knife coating method, or a curtain coating method should be used. Can do.

  In the case of forming a composite, in the undercoat layer 2, even if the metal oxide particles, the electron accepting substance, and the ionic substance react during the dispersion process to form a composite, the coating film is being dried and cured. A complex may be formed by reaction, but it is preferable to react in a dispersion because it reacts uniformly.

  The undercoat layer 2 can be formed by applying an undercoat layer forming coating solution on the conductive substrate 1 and removing the solvent by drying.

  The undercoat layer 2 preferably has a Vickers strength of 35 or more.

  Furthermore, the undercoat layer 2 may be set to any thickness as long as desired characteristics can be obtained, but the thickness is preferably 15 μm or more, and more preferably 15 to 50 μm. If the thickness of the undercoat layer 2 is less than 15 μm, sufficient leakage resistance tends to be difficult to obtain, and if it exceeds 50 μm, the residual potential tends to increase during long-term use, resulting in abnormal image density. It tends to be easy.

  Further, the surface roughness of the undercoat layer 2 is preferably adjusted to ¼n (n is the refractive index of the upper layer) to ½λ of the exposure laser wavelength λ used in order to prevent moire images. . At this time, particles such as a resin can be added to the undercoat layer 2 to adjust the surface roughness. As the resin particles, silicone resin particles, cross-linked PMMA resin particles, and the like can be used.

  Further, the undercoat layer 2 can be polished for adjusting the surface roughness. As a polishing method, buffing, sand blasting, wet honing, grinding, or the like can be used.

  The intermediate layer 4 is a layer provided between the undercoat layer 2 and the photosensitive layer 3 in order to improve electrical characteristics, improve image quality, improve image quality maintainability, improve photosensitive layer adhesion, and the like.

  The material constituting the intermediate layer 4 includes acetal resin such as polyvinyl butyral, polyvinyl alcohol resin, casein, polyamide resin, cellulose resin, gelatin, polyurethane resin, polyester resin, methacrylic resin, acrylic resin, polyvinyl chloride resin, polyvinyl acetate. In addition to polymer resin compounds such as resin, vinyl chloride-vinyl acetate-maleic anhydride resin, silicone resin, silicone-alkyd resin, phenol-formaldehyde resin, melamine resin, zirconium, titanium, aluminum, manganese, silicon atoms, etc. Examples thereof include organometallic compounds. These compounds can be used alone or as a mixture or polycondensate of a plurality of compounds. Among these, organometallic compounds containing zirconium or silicon are excellent in performance, such as low residual potential, little potential change due to environment, and little potential change due to repeated use.

  Examples of silicon compounds include vinyltrimethoxysilane, γ-methacryloxypropyl-tris (β-methoxyethoxy) silane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxy. Silane, vinyltriacetoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-β- (aminoethyl) -γ-aminopropyltrimethoxysilane, N-β- (aminoethyl) -γ -Aminopropylmethylmethoxysilane, N, N-bis (β-hydroxyethyl) -γ-aminopropyltriethoxysilane, γ-chloropropyltrimethoxysilane and the like. Among these, silicon compounds particularly preferably used are vinyltriethoxysilane, vinyltris (2-methoxyethoxysilane), 3-methacryloxypropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 2- (3,4). -Epoxycyclohexyl) ethyltrimethoxysilane, N-2- (aminoethyl) 3-aminopropyltrimethoxysilane, N-2- (aminoethyl) 3-aminopropylmethyldimethoxysilane, 3-aminopropyltriethoxysilane, N Examples include silane coupling agents such as phenyl-3-aminopropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, and 3-chloropropyltrimethoxysilane.

  Examples of organic zirconium compounds include zirconium butoxide, zirconium zirconium acetoacetate, zirconium triethanolamine, acetylacetonate zirconium butoxide, ethyl acetoacetate butoxide, zirconium acetate, zirconium oxalate, zirconium lactate, zirconium phosphonate, zirconium octoate, Zirconium naphthenate, zirconium laurate, zirconium stearate, zirconium isostearate, methacrylate zirconium butoxide, stearate zirconium butoxide, isostearate zirconium butoxide and the like.

  Examples of organic titanium compounds include tetraisopropyl titanate, tetranormal butyl titanate, butyl titanate dimer, tetra (2-ethylhexyl) titanate, titanium acetylacetonate, polytitanium acetylacetonate, titanium octylene glycolate, titanium lactate ammonium salt, Examples thereof include titanium lactate, titanium lactate ethyl ester, titanium triethanolamate, and polyhydroxytitanium stearate.

  Examples of the organoaluminum compound include aluminum isopropylate, monobutoxyaluminum diisopropylate, aluminum butyrate, diethyl acetoacetate aluminum diisopropylate, aluminum tris (ethyl acetoacetate) and the like.

  In addition to improving the coatability of the upper layer, the intermediate layer 4 also serves as an electrical blocking layer. However, if the film thickness is too large, the electrical barrier becomes too strong and the potential increases due to desensitization or repetition. Tend to cause. Accordingly, when the intermediate layer 4 is formed, it is preferable to set the film thickness within a range of 0.1 to 5 μm.

  The charge generation layer 31 constituting the photosensitive layer 3 is formed by forming a charge generation material by vacuum vapor deposition or by dispersing and applying the charge generation material together with an organic solvent and a binder resin.

  When the charge generation layer 31 is formed by dispersion coating, the charge generation material is dispersed together with an organic solvent, a binder resin, an additive, and the like to prepare a coating liquid for forming a charge generation layer, and the obtained coating liquid is intermediate It can be formed by coating on the layer 4 and drying.

  As the charge generation material, known charge generation materials can be used without particular limitation. As the charge generation material for infrared light, phthalocyanine pigment, squarylium, bisazo, trisazo, perylene, dithioketopyrrolopyrrole, etc. are used, and as the charge generation material for visible light, condensed polycyclic pigment, bisazo, perylene, Trigonal selenium, dye-sensitized zinc oxide particles and the like are used. Among these, particularly excellent performance is obtained, and charge generating materials that are preferably used are phthalocyanine pigments and azo pigments. By using these charge generation materials, it is possible to obtain an electrophotographic photosensitive member having particularly high sensitivity and excellent repeatability. In addition, phthalocyanine pigments and azo pigments generally have several crystal types, and any of these crystal types can be used as long as it is a crystal type capable of obtaining electrophotographic characteristics suitable for the purpose. . Particularly preferred charge generating materials include chlorogallium phthalocyanine, dichlorosus phthalocyanine, hydroxygallium phthalocyanine, metal-free phthalocyanine, oxytitanyl phthalocyanine, chloroindium phthalocyanine, and the like.

  The phthalocyanine pigment crystal is obtained by mechanically dry-pulverizing a phthalocyanine pigment produced by a known method with an automatic mortar, planetary mill, vibration mill, CF mill, roller mill, sand mill, kneader, etc. It can manufacture by performing a wet grinding process using a ball mill, a mortar, a sand mill, a kneader, etc.

  Solvents used in the wet pulverization treatment include aromatics (toluene, chlorobenzene, etc.), amides (dimethylformamide, N-methylpyrrolidone, etc.), aliphatic alcohols (methanol, ethanol, butanol, etc.), aliphatic poly Monohydric alcohols (ethylene glycol, glycerin, polyethylene glycol, etc.), aromatic alcohols (benzyl alcohol, phenethyl alcohol, etc.), esters (acetic ester, butyl acetate, etc.), ketones (acetone, methyl ethyl ketone, etc.), dimethyl sulfoxide, Examples include ethers (diethyl ether, tetrahydrofuran, etc.), several mixed systems, and mixed systems of water and these organic solvents.

  The amount of these solvents to be used is preferably 1 to 200 parts by mass, more preferably 10 to 100 parts by mass with respect to 1 part by mass of the pigment crystal. The treatment temperature in the wet pulverization treatment is preferably in the range of −20 ° C. or higher and the boiling point of the solvent or lower, more preferably in the range of −10 to 60 ° C. In addition, grinding aids such as sodium chloride and sodium nitrate can be used during grinding. The grinding aid may be used 0.5 to 20 times, preferably 1 to 10 times (all in terms of mass) with respect to the pigment.

  Moreover, about the pigment crystal manufactured by a well-known method, crystal | crystallization control can also be carried out by the combination of acid pasting or acid pasting and the above-mentioned dry grinding or wet grinding. The acid used for acid pasting is preferably sulfuric acid, and the concentration of this sulfuric acid is preferably 70 to 100%, more preferably 95 to 100%. The amount of the concentrated sulfuric acid is preferably set in the range of 1 to 100 times, more preferably 3 to 50 times (both in terms of mass) with respect to the mass of the pigment crystals. The dissolution temperature is preferably set in the range of -20 to 100 ° C, more preferably -10 to 60 ° C. As a solvent for precipitating crystals from an acid, water or a mixed solvent of water and an organic solvent can be used in an arbitrary amount. The temperature for precipitation is not particularly limited, but it is preferably cooled with ice or the like in order to prevent heat generation.

  The binder resin used for the charge generation layer 31 can be selected from a wide range of insulating resins. It can also be selected from organic photoconductive polymers such as poly-N-vinyl carbazole, polyvinyl anthracene, polyvinyl pyrene and polysilane. Preferred binder resins include polyvinyl acetal resin, polyarylate resin (polycondensate of bisphenol A and phthalic acid, etc.), polycarbonate resin, polyester resin, phenoxy resin, vinyl chloride-vinyl acetate copolymer, polyamide resin, acrylic resin Insulating resins such as polyacrylamide resin, polyvinyl pyridine resin, cellulose resin, urethane resin, epoxy resin, casein, polyvinyl alcohol resin, polyvinyl pyrrolidone resin can be mentioned, but are not limited thereto. These binder resins can be used alone or in admixture of two or more. Of these, polyvinyl acetal resin is particularly preferably used.

  The charge generation layer 31 is formed by vacuum deposition of a charge generation material or application of a charge generation layer forming coating solution containing a charge generation material and a binder resin. In the charge generating layer forming coating solution, the blending ratio (mass ratio) of the charge generating material and the binder resin is preferably in the range of 10: 1 to 1:10. The solvent for adjusting the coating solution can be arbitrarily selected from known organic solvents such as alcohols, aromatics, halogenated hydrocarbons, ketones, ketone alcohols, ethers and esters. . More specifically, examples of the solvent include methanol, ethanol, n-propanol, iso-propanol, n-butanol, benzyl alcohol, methyl cellosolve, ethyl cellosolve, acetone, methyl ethyl ketone, cyclohexanone, methyl acetate, ethyl acetate, acetic acid. Usual organic solvents such as n-butyl, dioxane, tetrahydrofuran, methylene chloride, chloroform, chlorobenzene, and toluene can be used. These solvents can be used alone or in admixture of two or more. When two or more kinds are mixed, any solvent can be used as long as it can dissolve the binder resin as a mixed solvent.

  As a method for dispersing the charge generation material and the binder resin in a solvent, methods such as a roll mill, a ball mill, a vibrating ball mill, an attritor, a sand mill, a colloid mill, and a paint shaker can be used. In this dispersion, it is effective for high sensitivity and high stability that the charge generating material has a particle size of 0.5 μm or less, preferably 0.3 μm or less, more preferably 0.15 μm or less.

  Further, as a coating method used for forming the charge generation layer 31, the blade coating method, the wire bar coating method, the spray coating method, the dip coating method, the bead coating method, the air knife coating method, the curtain coating method and the like are used. The method can be used.

  In addition, the charge generation material can be subjected to a surface treatment in order to improve the stability of electrical characteristics and prevent image quality defects. As the surface treatment agent, a coupling agent, an organic zirconium compound, an organic titanium compound, an organoaluminum compound, and the like can be used, but the surface treatment agent is not limited thereto.

  Examples of coupling agents used for the surface treatment include vinyltrimethoxysilane, γ-methacryloxypropyl-tris (β-methoxyethoxy) silane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycol. Sidoxypropyltrimethoxysilane, vinyltriacetoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-β- (aminoethyl) -γ-aminopropyltrimethoxysilane, N-β- ( Examples of the silane coupling agent include aminoethyl) -γ-aminopropylmethylmethoxysilane, N, N-bis (β-hydroxyethyl) -γ-aminopropyltriethoxysilane, and γ-chloropropyltrimethoxysilane. Particularly preferred silane coupling agents are vinyltriethoxysilane, vinyltris (2-methoxyethoxysilane), 3-methacryloxypropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 2- (3,4 -Epoxycyclohexyl) ethyltrimethoxysilane, N-2- (aminoethyl) 3-aminopropyltrimethoxysilane, N-2- (aminoethyl) 3-aminopropylmethyldimethoxysilane, 3-aminopropyltriethoxysilane, N Examples include silane coupling agents such as phenyl-3-aminopropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, and 3-chloropropyltrimethoxysilane.

  Examples of the organic zirconium compound include zirconium butoxide, zirconium zirconium acetoacetate, zirconium triethanolamine, acetylacetonate zirconium butoxide, ethyl acetoacetate butoxide, zirconium acetate, zirconium oxalate, zirconium lactate, zirconium phosphonate, zirconium octoate, Zirconium naphthenate, zirconium laurate, zirconium stearate, zirconium isostearate, methacrylate zirconium butoxide, stearate zirconium butoxide, isostearate zirconium butoxide and the like.

  Further, as the organic titanium compound, tetraisopropyl titanate, tetranormal butyl titanate, butyl titanate dimer, tetra (2-ethylhexyl) titanate, titanium acetylacetonate, polytitanium acetylacetonate, titanium octylene glycolate, titanium lactate ammonium salt , Titanium lactate, titanium lactate ethyl ester, titanium triethanolamate, polyhydroxy titanium stearate and the like.

  Examples of the organoaluminum compound include aluminum isopropylate, monobutoxyaluminum diisopropylate, aluminum butyrate, diethyl acetoacetate aluminum diisopropylate, and aluminum tris (ethyl acetoacetate).

  Furthermore, various additives can be added to the coating solution for forming the charge generation layer in order to improve electrical characteristics and image quality. Additives include quinone compounds such as chloranil, bromoanil and anthraquinone, tetracyanoquinodimethane compounds, fluorenones such as 2,4,7-trinitrofluorenone and 2,4,5,7-tetranitro-9-fluorenone Compounds, 2- (4-biphenyl) -5- (4-t-butylphenyl) -1,3,4-oxadiazole and 2,5-bis (4-naphthyl) -1,3,4-oxadi Azoles, oxadiazole compounds such as 2,5-bis (4-diethylaminophenyl) 1,3,4 oxadiazole, xanthone compounds, thiophene compounds, 3,3 ′, 5,5 ′ tetra-t-butyl Electron transporting materials such as diphenoquinone compounds such as diphenoquinone, electron transporting pigments such as polycyclic condensation systems and azo systems, zirconium chelate compounds, titanium Chelate compounds, aluminum chelate compounds, titanium alkoxide compounds, organic titanium compounds, there can be used a known material such as a silane coupling agent.

  Examples of silane coupling agents include vinyltrimethoxysilane, γ-methacryloxypropyl-tris (β-methoxyethoxy) silane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropyl. Trimethoxysilane, vinyltriacetoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-β- (aminoethyl) -γ-aminopropyltrimethoxysilane, N-β- (aminoethyl) -Γ-aminopropylmethylmethoxysilane, N, N-bis (β-hydroxyethyl) -γ-aminopropyltriethoxysilane, γ-chloropropyltrimethoxysilane, and the like.

  Examples of zirconium chelate compounds include zirconium butoxide, zirconium zirconium acetoacetate, zirconium triethanolamine, acetylacetonate zirconium butoxide, ethyl acetoacetate butoxide, zirconium acetate, zirconium oxalate, zirconium lactate, zirconium phosphonate, zirconium octoate, Zirconium naphthenate, zirconium laurate, zirconium stearate, zirconium isostearate, methacrylate zirconium butoxide, stearate zirconium butoxide, isostearate zirconium butoxide and the like.

  Examples of titanium chelate compounds include tetraisopropyl titanate, tetranormal butyl titanate, butyl titanate dimer, tetra (2-ethylhexyl) titanate, titanium acetylacetonate, polytitanium acetylacetonate, titanium octylene glycolate, titanium lactate ammonium salt , Titanium lactate, titanium lactate ethyl ester, titanium triethanolamate, polyhydroxy titanium stearate and the like.

  Examples of the aluminum chelate compound include aluminum isopropylate, monobutoxy aluminum diisopropylate, aluminum butyrate, diethyl acetoacetate aluminum diisopropylate, aluminum tris (ethyl acetoacetate) and the like.

  These compounds can be used alone or as a mixture or polycondensate of a plurality of compounds.

  The charge transport layer 32 includes, for example, a charge transport material and a binder resin. Any known material can be used as the charge transporting material contained in the charge transporting layer 32, such as 2,5-bis (p-diethylaminophenyl) -1,3,4-oxadiazole. Oxadiazole derivatives, pyrazoline derivatives such as 1,3,5-triphenyl-pyrazoline, 1- [pyridyl- (2)]-3- (p-diethylaminostyryl) -5- (p-diethylaminostyryl) pyrazoline, Triphenylamine, tri (P-methyl) phenylamine, N, N′-bis (3,4-dimethylphenyl) biphenyl-4-amine, dibenzylaniline, 9,9-dimethyl-N, N′-di ( p-tolyl) aromatic tertiary amino compounds such as fluorenone-2-amine, N, N′-diphenyl-N, N′-bis (3-methylphenyl)- Aromatic tertiary diamino compounds such as 1,1-biphenyl] -4,4′-diamine, 3- (4′dimethylaminophenyl) -5,6-di- (4′-methoxyphenyl) -1,2 1,2,4-triazine derivatives such as 1,4-triazine, 4-diethylaminobenzaldehyde-1,1-diphenylhydrazone, 4-diphenylaminobenzaldehyde-1,1-diphenylhydrazone, [p- (diethylamino) phenyl] (1 A hydrazone derivative such as -naphthyl) phenylhydrazone, a quinazoline derivative such as 2-phenyl-4-styryl-quinazoline, a benzofuran derivative such as 6-hydroxy-2,3-di (p-methoxyphenyl) -benzofuran, p- (2 , 2-diphenylvinyl) -N, N′-diphenylaniline and other α-stilbene derivatives, Namin derivatives, carbazole derivatives such as N-ethylcarbazole, hole transport materials such as poly-N-vinylcarbazole and its derivatives, quinone compounds such as chloranil, bromoanil, anthraquinone, tetracyanoquinodimethane compounds, 2, 4 , 7-trinitrofluorenone, 2,4,5,7-tetranitro-9-fluorenone and the like, 2- (4-biphenyl) -5- (4-t-butylphenyl) -1,3,4- Oxadiazoles such as oxadiazole, 2,5-bis (4-naphthyl) -1,3,4-oxadiazole, 2,5-bis (4-diethylaminophenyl) 1,3,4 oxadiazole Compounds, xanthone compounds, thiophene compounds, dipheno such as 3,3 ′, 5,5′tetra-t-butyldiphenoquinone Polymer or the like having an electron transport material, such as non-compound, or a compound group shown above in the main chain or side chain. These charge transport materials can be used alone or in combination of two or more. From the viewpoint of mobility, these charge transport materials are represented by the following general formula (a-1), (a-2) or (a-3). It is preferable to use a compound.

In the formula (a-1), R ²¹ represents a hydrogen atom or a methyl group, and k1 represents 1 or 2. Ar ¹¹ and Ar ¹² are each a substituted or unsubstituted aryl group, —C ₆ H ₄ —C (R ²⁸ ) ═C (R ²⁹ ) (R ³⁰ ), or —C ₆ H ₄ —CH═CH—. CH = C (Ar ²¹ ) ₂ represents a substituent substituted with a halogen atom, an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, or an alkyl group having 1 to 3 carbon atoms. An amino group is mentioned. R ²⁸ , R ²⁹ and R ³⁰ represent a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group, and Ar ²¹ represents a substituted or unsubstituted aryl group.

In the formula ^{(a-2), R 22} , R 22 ' may be the same or different, a hydrogen atom, a halogen atom, an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, a. R ²³ , R ²³ ′, R ^24, and R ²⁴ ′ may be the same or different, and are a halogen atom, an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, or an alkyl group having 1 to 2 carbon atoms. amino group substituted with an alkyl group, a substituted or unsubstituted aryl ^{_{group, -C 6 H 4 -C (R}} 28) = C (R 29) (R 30), _or, -C ₆ H 4 -CH = CH —CH═C (Ar ²¹ ) ₂ , R ²⁸ , R ²⁹ , and R ³⁰ represent a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group, and Ar ²¹ represents a substituted or An unsubstituted aryl group is shown. k2 and k3 represent an integer of 0-2.

In the above formula (a-3), R ²⁵ represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, a substituted or unsubstituted aryl group, or —C ₆ H ₄ —CH. = indicates a ^{CH-CH = C (Ar 21} ) 2. Ar ²¹ represents a substituted or unsubstituted aryl group. R ²⁶ and R ²⁷ are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, an amino group substituted with an alkyl group having 1 to 2 carbon atoms, or A substituted or unsubstituted aryl group is shown.

  Any binder resin can be used as the binder resin used for the charge transport layer 32, but a resin capable of forming an electrically insulating film is preferable. Examples of the binder resin include polycarbonate resin, polyester resin, methacrylic resin, acrylic resin, polyvinyl chloride resin, polyvinylidene chloride resin, polystyrene resin, polyvinyl acetate resin, styrene-butadiene copolymer, vinylidene chloride-acrylonitrile copolymer. Polymer, vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinyl acetate-maleic anhydride copolymer, silicone resin, silicone-alkyd resin, phenol-formaldehyde resin, styrene-alkyd resin, poly-N-vinylcarbazole, Polysilanes and polymer charge transport materials such as polyester polymer charge transport materials disclosed in JP-A-8-176293 and JP-A-8-208820 can also be used. Among these, a polycarbonate resin, a polyester resin, a methacrylic resin, and an acrylic resin are preferably used because they are excellent in compatibility with a charge transport material, solubility in a solvent, and strength. These binder resins can be used individually by 1 type or in mixture of 2 or more types. The mixing ratio (mass ratio) between the binder resin and the charge transport material can be arbitrarily set in any case, but attention must be paid to a decrease in electrical characteristics and a decrease in film strength.

  A polymer charge transport material can also be used alone. As the polymer charge transport material, known materials having charge transport properties such as poly-N-vinylcarbazole and polysilane can be used. In particular, polyester polymer charge transport materials disclosed in JP-A-8-176293 and JP-A-8-208820 have a high charge transporting property and are particularly preferable. The polymer charge transport material alone can be used as the charge transport layer, but it may be formed by mixing with the binder resin.

  The charge transport layer 32 is formed by applying a charge transport layer forming coating solution in which a charge transport substance, a binder resin, and other materials are dissolved in an appropriate solvent on the charge transport layer 31 and drying. Can do. Examples of the solvent used in the coating solution for forming the charge transport layer include aromatic hydrocarbon solvents such as toluene and chlorobenzene, aliphatic alcohol solvents such as methanol, ethanol and n-butanol, acetone, cyclohexanone and 2-butanone. Ketone solvents, halogenated aliphatic hydrocarbon solvents such as methylene chloride, chloroform and ethylene chloride, cyclic or linear ether solvents such as tetrahydrofuran, dioxane, ethylene glycol and diethyl ether, or a mixed solvent thereof. be able to. The mixing ratio (mass ratio) of the charge transport material and the binder resin is preferably 10: 1 to 1: 5.

  Further, a slight amount of a leveling agent such as silicone oil for improving the smoothness of the coating film can be added to the coating solution for forming the charge transport layer.

  As a coating method when the charge transport layer forming coating solution is coated on the charge generation layer 31, a dip coating method, a push-up coating method, a spray coating method, a roll coater coating method, a wire bar coating method, a gravure coater coating method, A bead coating method, a curtain coating method, a blade coating method, an air knife coating method, or the like can be used.

  The thickness of the charge transport layer 32 is preferably 5 to 50 μm, and more preferably 10 to 45 μm.

  In the electrophotographic photosensitive member of the present invention, for the purpose of preventing deterioration of the electrophotographic photosensitive member due to ozone, oxidizing gas, light or heat generated in the image forming apparatus, an antioxidant or light is contained in the photosensitive layer 3. Additives such as stabilizers can be added.

  Examples of the antioxidant include hindered phenol, hindered amine, paraphenylenediamine, arylalkane, hydroquinone, spirochroman, spiroidanone and derivatives thereof, organic sulfur compounds, and organic phosphorus compounds.

  Specific examples of antioxidants include phenolic antioxidants such as 2,6-di-t-butyl-4-methylphenol, styrenated phenol, n-octadecyl-3- (3 ′, 5 ′. -Di-t-butyl-4'-hydroxyphenyl) -propionate, 2,2'-methylene-bis- (4-methyl-6-t-butylphenol), 2-t-butyl-6- (3'-t -Butyl-5'-methyl-2'-hydroxybenzyl) -4-methylphenyl acrylate, 4,4'-butylidene-bis- (3-methyl-6-tert-butyl-phenol), 4,4'-thio -Bis- (3-methyl-6-tert-butylphenol), 1,3,5-tris (4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl) isocyanurate, tetrakis- [methyle -3- (3 ', 5'-di-t-butyl-4'-hydroxy-phenyl) propionate] -methane, 3,9-bis [2- [3- (3-t-butyl-4-hydroxy- 5-methylphenyl) propionyloxy] -1,1-dimethylethyl] -2,4,8,10-tetraoxaspiro [5,5] undecane and the like.

  Examples of hindered amine compounds include bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, 1- [2- [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionyloxy] ethyl] -4- [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionyloxy]- 2,2,6,6-tetramethylpiperidine, 8-benzyl-7,7,9,9-tetramethyl-3-octyl-1,3,8-triazaspiro [4,5] undecane-2,4-dione 4-benzoyloxy-2,2,6,6-tetramethylpiperidine, dimethyl-1- (2-hydroxyethyl) -4-hydroxy-2,2,6,6-tetramethylpiperidine succinate Polycondensate, poly [{6- (1,1,3,3-tetramethylbutyl) imino-1,3,5-triazine-2,4-diimyl} {(2,2,6,6-tetra Methyl-4-piperidyl) imino} hexamethylene {(2,3,6,6-tetramethyl-4-piperidyl) imino}], 2- (3,5-di-t-butyl-4-hydroxybenzyl) 2-n-butylmalonate bis (1,2,2,6,6-pentamethyl-4-piperidyl), N, N′-bis (3-aminopropyl) ethylenediamine-2,4-bis [N-butyl -N- (1,2,2,6,6-pentamethyl-4piperidyl) amino] -6-chloro-1,3,5-triazine condensate and the like.

  Examples of organic sulfur antioxidants include dilauryl-3,3′-thiodipropionate, dimyristyl-3,3′-thiodipropionate, distearyl-3,3′-thiodipropionate, pentaerythritol-tetrakis. -(Β-lauryl-thiopropionate), ditridecyl-3,3′-thiodipropionate, 2-mercaptobenzimidazole and the like.

  Examples of the organophosphorus antioxidant include trisnonylphenyl phosfte, triphenyl phosfte, tris (2,4-di-t-butylphenyl) -phosfte, and the like.

  Organic sulfur-based and organic phosphorus-based antioxidants are said to be secondary antioxidants, and a synergistic effect can be obtained by using them together with primary antioxidants such as phenol-based or amine-based antioxidants.

  Examples of the light stabilizer include benzophenone, benzotriazole, dithiocarbamate, and tetramethylpiperidine derivatives.

  Examples of the benzophenone light stabilizer include 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, 2,2'-di-hydroxy-4-methoxybenzophenone, and the like. 2- (2′-hydroxy-5′methylphenyl) -benzotriazole, 2- [2′-hydroxy-3 ′-(3 ″, 4 ″, 5 ″, 6 ′) as benzotriazole light stabilizer '-Tetrahydrophthalimidomethyl) -5'-methylphenyl] -benzotriazole, 2- (2'-hydroxy-3'-tert-butyl5'-methylphenyl) -5-chlorobenzotriazole, 2- (2'- Hydroxy-3'-t-butyl-5'-methylphenyl) -5-chlorobenzotriazole, 2- (2'-hydroxy-3 ', 5'-t-butylphenyl) -benzotriazole, 2- (2' -Hydroxy-5'-t-octylphenyl) -benzotriazole, 2- (2'-hydroxy-3 ', 5'-di-t-amylphenyl) -benzotriazole, etc. And the like.

  As other compounds, 2,4-di-t-butylphenyl-3 ', 5'-di-t-butyl-4'-hydroxybenzoate, nickel dibutyl-dithiocarbamate, and the like may be used.

  In addition, at least one kind of electron-accepting substance can be contained for the purpose of improving sensitivity, reducing residual potential, and reducing fatigue during repeated use.

Examples of the electron accepting substance include succinic anhydride, maleic anhydride, dibromomaleic anhydride, phthalic anhydride, tetrabromophthalic anhydride, tetracyanoethylene, tetracyanoquinodimethane, o-dinitrobenzene, m-dinitrobenzene. , Chloranil, dinitroanthraquinone, trinitrofluorenone, picric acid, o-nitrobenzoic acid, p-nitrobenzoic acid, phthalic acid and the like. Of these, fluorenone-based, quinone-based, and benzene derivatives having an electron-withdrawing substituent such as Cl, CN, NO ₂ are particularly preferable.

  In the electrophotographic photoreceptor 100 having a laminated structure, the protective layer 5 prevents chemical change of the charge transport layer 32 during charging, improves the mechanical strength of the photosensitive layer 3, and wears or scratches the surface layer. Used to further improve resistance.

  Examples of the form of the protective layer 5 include a cured resin film including a curable resin and a charge transporting compound, a film formed by containing a conductive material in a suitable binder resin, and the like. What is contained is preferably used. The curable resin can be used without particular limitation as long as it is a known resin, but in particular from the viewpoint of strength, electrical characteristics and image quality maintenance, those having a crosslinked structure are preferable, for example, phenol resin, urethane resin, melamine resin, Examples include diallyl phthalate resin and siloxane resin.

  Further, the charge transporting compound used for the protective layer 5 has a reactive functional group and is preferably compatible with the curable resin used, and further has a chemical bond with the curable resin used. What is formed is more preferred. As the charge transport compound having a reactive functional group, a compound represented by the following general formula (I), (II), (III), (IV), (V) or (VI) is preferable.

F [-D-Si (R ¹ ) _(3-a) Q _a ] _b (I)
[In Formula (I), F represents an organic group derived from a compound having a hole transporting ability, D represents a divalent group having flexibility, and R ¹ represents a hydrogen atom, a substituted or unsubstituted group. An alkyl group or a substituted or unsubstituted aryl group, Q represents a hydrolyzable group, a represents an integer of 1 to 3, and b represents an integer of 1 to 4; ]

F [— (X ¹ ) _n1 R ² —Z ¹ H] _m1 (II)
[In Formula (II), F represents an organic group derived from a compound having a hole transporting ability, R ² represents an alkylene group, Z ¹ represents an oxygen atom, a sulfur atom, NH or COO, and X ¹ Represents an oxygen atom or a sulfur atom, m1 represents an integer of 1 to 4, and n1 represents 0 or 1. ]

^{_{F [- (X 2) n2}} - (R 3) n3 - (Z 2) n4 G] n5 (III)
[In Formula (III), F represents an organic group derived from a compound having a hole transporting ability, X ² represents an oxygen atom or a sulfur atom, R ³ represents an alkylene group, Z ² represents an oxygen atom, S represents a sulfur atom, NH or COO, G represents an epoxy group, n2, n3 and n4 each independently represents 0 or 1, and n5 represents an integer of 1 to 4. ]

［式（ＩＶ）中、Ｆは正孔輸送性を有する化合物から誘導される有機基を示し、Ｔは２価の基を示し、Ｙは酸素原子又は硫黄原子を示し、Ｒ^４、Ｒ^５及びＲ^６はそれぞれ独立に水素原子又は１価の有機基を示し、Ｒ^７は１価の有機基を示し、ｍ２は０又は１を示し、ｎ６は１〜４の整数を示す。但し、Ｒ^６とＲ^７は互いに結合してＹをヘテロ原子とする複素環を形成してもよい。］

[In Formula (IV), F represents an organic group derived from a compound having a hole transporting property, T represents a divalent group, Y represents an oxygen atom or a sulfur atom, R ⁴ , R ⁵ and R ⁶ independently represents a hydrogen atom or a monovalent organic group, R ⁷ represents a monovalent organic group, m 2 represents 0 or 1, and n 6 represents an integer of 1 to 4. However, R ⁶ and R ⁷ may combine with each other to form a heterocycle having Y as a heteroatom. ]

［式（Ｖ）中、Ｆは正孔輸送性を有する化合物から誘導される有機基を示し、Ｔは２価の基を示し、Ｒ^８は１価の有機基を示し、ｍ３は０又は１を示し、ｎ７は１〜４の整数を示す。］

[In Formula (V), F represents an organic group derived from a compound having a hole transporting property, T represents a divalent group, R ⁸ represents a monovalent organic group, and m3 represents 0 or 1 N7 represents an integer of 1 to 4. ]

［式（ＶＩ）中、Ｆは正孔輸送性を有する化合物から誘導される有機基を示し、Ｒ^９は１価の有機基を示し、Ｌはアルキレン基を示し、ｎ８は１〜４の整数を示す。］

[In Formula (VI), F represents an organic group derived from a compound having a hole transporting property, R ⁹ represents a monovalent organic group, L represents an alkylene group, and n8 represents an integer of 1 to 4. Indicates. ]

  In the above general formulas (I) to (VI), F is a unit having photoelectric characteristics, specifically, photocarrier transport characteristics, and a structure conventionally known as a charge transport material can be used as it is. . Specifically, compound skeletons having hole transport properties such as triarylamine compounds, benzidine compounds, arylalkane compounds, aryl-substituted ethylene compounds, stilbene compounds, anthracene compounds, hydrazone compounds, and quinones A compound skeleton having an electron transporting property such as a compound, a fluorenone compound, a xanthone compound, a benzophenone compound, a cyanovinyl compound, or an ethylene compound can be used.

In the general formula (I), —Si (R ¹ ) _(3-a) Q _a is a substituted silicon group having a hydrolyzable group, and the substituted silicon undergoes a crosslinking reaction with the Si group. A three-dimensional Si—O—Si bond is formed. That is, this substituted silicon group plays a role of forming a so-called inorganic glassy network in the protective layer 5.

In the above general formula (I), D represents a divalent group having flexibility. Specifically, it is directly bonded to an F site for imparting photoelectric characteristics and a three-dimensional inorganic glassy network. An organic group that plays a role in linking to a substituted silicon group that is tied in, and gives moderate flexibility to an inorganic glassy network that is hard but brittle, and improves the toughness of the film. To express. Specific examples _{D, -C n H 2n -,} - C n H (2n-2) -, - C n H (2n-4) - 2 divalent hydrocarbon group (here represented, n is represents an integer of _{1~15), - COO -, -} S -, - O -, - CH 2 -C 6 H 4 -, - N = CH -, - (C 6 H 4) - (C 6 H 4 )-And a characteristic group arbitrarily combining these, and those obtained by substituting structural atoms of these characteristic groups with other substituents.

  In the general formula (I), b is preferably 2 or more. When b is 2 or more, the photofunctional organosilicon compound represented by the general formula (I) contains two or more Si atoms, and it becomes easy to form an inorganic glassy network, and mechanical strength is increased. Will improve.

  The F in the compounds represented by the general formulas (I) to (VI) is preferably a group represented by the following general formula (VII). The group represented by the following general formula (VII) is a group having a hole transporting ability, and the inclusion of this in the protective layer 5 is particularly preferable from the viewpoint of improving the photoelectric characteristics and mechanical characteristics in the protective layer 5.

［式（ＶＩＩ）中、Ａｒ^１、Ａｒ^２、Ａｒ^３及びＡｒ^４はそれぞれ独立に置換又は未置換のアリール基を示し、Ａｒ^５は置換若しくは未置換のアリール基又はアリーレン基を示し、且つＡｒ^１〜Ａｒ^５のうち１〜４個は、上記一般式（Ｉ）で表わされる化合物における下記一般式（ＶＩＩＩ）で示される部位、上記一般式（ＩＩ）で表わされる化合物における下記一般式（ＩＸ）で示される部位、上記一般式（ＩＩＩ）で表わされる化合物における下記一般式（Ｘ）で示される部位、上記一般式（ＩＶ）で表わされる化合物における下記一般式（ＸＩ）で示される部位、上記一般式（Ｖ）で表わされる化合物における下記一般式（ＸＩＩ）で示される部位、又は、上記一般式（ＶＩ）で表わされる化合物における下記一般式（ＸＩＩＩ）で示される部位、と結合するための結合手を有し、ｋは０又は１を示す。］

[In formula (VII), Ar ¹ , Ar ² , Ar ³ and Ar ⁴ each independently represent a substituted or unsubstituted aryl group, Ar ⁵ represents a substituted or unsubstituted aryl group or an arylene group, and Ar ^{1 to} 4 of ^{1 to} Ar ⁵ are a moiety represented by the following general formula (VIII) in the compound represented by the above general formula (I), a general formula (IX) in the compound represented by the above general formula (II), ), A site represented by the following general formula (X) in the compound represented by the above general formula (III), a site represented by the following general formula (XI) in the compound represented by the above general formula (IV), The moiety represented by the following general formula (XII) in the compound represented by the general formula (V), or the following general formula (XIII) in the compound represented by the general formula (VI) ), And k represents 0 or 1. ]

^{_{-D-Si (R 1) (}} 3-a) Q a (VIII)
^{_{- (X 1) n1 R 1}} -Z 1 H (IX)
^{_{- (X 2) n2 - (}} R 2) n3 - (Z 2) n4 G (X)

In addition, as the substituted or unsubstituted aryl group represented by Ar ^{1 to} Ar ⁴ in the general formula (VII), specifically, aryl groups represented by the following general formulas (1) to (7) are preferable. .

The formula (1) ~ ^{(7), R 11} is a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkyl group having 1 to 4 carbon atoms, alkoxy group having 1 to 4 carbon atoms, phenyl which is substituted by them A group or an unsubstituted phenyl group, or an aralkyl group having 7 to 10 carbon atoms, wherein R ^{12 to} R ¹⁴ are a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, and a carbon number, respectively. 1 to 4 alkoxy groups, phenyl or unsubstituted phenyl groups substituted therewith, aralkyl groups having 7 to 10 carbon atoms or halogen atoms, Ar represents a substituted or unsubstituted arylene group, and X represents the above One of the structures represented by the general formulas (VIII) to (XIII) is shown, c and s each represent 0 or 1, and t represents an integer of 1 to 3.

  Moreover, as Ar in the aryl group represented by the above formula (7), an arylene group represented by the following formula (8) or (9) is preferable.

In the above formulas (8) and (9), R ¹⁵ and R ¹⁶ are each substituted with a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, and an alkoxy group having 1 to 4 carbon atoms. A phenyl group, an unsubstituted phenyl group, an aralkyl group having 7 to 10 carbon atoms, or a halogen atom, and t represents an integer of 1 to 3.

  Moreover, as Z 'in the aryl group represented by the above formula (7), divalent groups represented by the following formulas (10) to (17) are preferable.

In the above formulas (10) to (17), R ¹⁷ and R ¹⁸ are each substituted with a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, and an alkoxy group having 1 to 4 carbon atoms. A phenyl group, an unsubstituted phenyl group, an aralkyl group having 7 to 10 carbon atoms, or a halogen atom, W represents a divalent group, q and r each represent an integer of 1 to 10, and t Represents an integer of 1 to 3, respectively.

  In the above formulas (16) to (17), W represents a divalent group represented by the following formulas (18) to (26). In formula (25), u represents an integer of 0 to 3.

In addition, the specific structure of Ar ⁵ in the general formula (VII) is as follows. When k = 0, the structure of c = 1 in the specific structure of Ar ^{1 to} Ar ⁴ and when Ar = 1, the Ar 5 ^The structure of c = 0 in the specific structure of ^{1 to} Ar ⁴ is given.

  Specific examples of the compound represented by the general formula (I) in the case where F is a group represented by the general formula (VII) include, for example, Tables 1 to 1 in JP-A-2001-83728. Compounds having compound numbers 1 to 274 shown in Table 55 can be used.

  The charge transporting compounds represented by the general formulas (I) to (VI) may be used alone or in combination of two or more.

  Further, the protective layer 5 has a charge transporting compound represented by the above general formula (I) and 2 represented by the following general formula (XIV) for the purpose of further improving the mechanical strength of the cured film. It is also preferable to use a compound having two or more silicon atoms.

B- (Si (R ⁴⁰ ) _(3-a) Q _a ) ₂ (XIV)
[In formula (XIV), B represents a divalent organic group, R ⁴⁰ represents a hydrogen atom, an alkyl group or a substituted or unsubstituted aryl group, Q represents a hydrolyzable group, and a represents 1 to 3 Indicates an integer. ]

Although it does not specifically limit as a compound represented by the said general formula (XIV), For example, the compound represented by the following compounds (XIV-1)-(XIV-5) can be mentioned as a preferable thing. In formulas (XIV-1) to (XIV-5), T ¹ and T ² each independently represent a divalent or trivalent hydrocarbon group which may be branched. A represents a substituted silicon group having hydrolyzability represented by -SiR ⁴⁰ _(3-a) Q _a . h, i, and j each independently represent an integer of 1 to 3. The compounds represented by formulas (XIV-1) to (XIV-5) are selected so that the number of A in the molecule is 2 or more.

  Preferred examples of the compound represented by the general formula (XIV) are shown below. In the following table, Me represents a methyl group, Et represents an ethyl group, and Pr represents a propyl group.

  In addition to the compound represented by the general formula (I), another compound capable of crosslinking reaction may be used in combination. As such a compound, various silane coupling agents, commercially available silicone hard coat agents, and the like can be used.

  Examples of the silane coupling agent include vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropyltrimethoxysilane, and γ-glycidoxypropyl. Trimethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropylmethyldimethoxysilane, N-β (aminoethyl) γ-aminopropyltriethoxysilane, tetramethoxysilane, methyltrimethoxy Examples thereof include silane and dimethyldimethoxysilane.

  As a commercially available hard coat agent, KP-85, CR-39, X-12-2208, X-40-9740, X-41-1007, KNS-5300, X-40-2239 (above, manufactured by Shin-Etsu Silicone Co., Ltd.) ), AY42-440, AY42-441, AY49-208 (manufactured by Toray Dow Corning), and the like.

  Further, a fluorine atom-containing compound can be added to the protective layer 5 for the purpose of imparting surface lubricity. By improving the surface lubricity, the coefficient of friction with the cleaning member decreases, and the wear resistance can be improved. In addition, it has an effect of preventing adhesion of discharge products, developer, paper dust, and the like to the surface of the electrophotographic photosensitive member, which is useful for improving the life of the electrophotographic photosensitive member 100.

  As the fluorine-containing compound, a fluorine atom-containing polymer such as polytetrafluoroethylene can be added as it is, or particles of these polymers can be added.

  Further, in the case where the protective layer 5 is a cured film formed of the compound represented by the general formula (I), a fluorine-containing compound that can react with alkoxysilane is added to constitute a part of the crosslinked film. Is desirable.

  Specific examples of such a fluorine atom-containing compound include (tridecafluoro-1,1,2,2-tetrahydrooctyl) triethoxysilane, (3,3,3-trifluoropropyl) trimethoxysilane, 3- (Heptafluoroisopropoxy) propyltriethoxysilane, 1H, 1H, 2H, 2H-perfluoroalkyltriethoxysilane, 1H, 1H, 2H, 2H-perfluorodecyltriethoxysilane, 1H, 1H, 2H, 2H-per And fluorooctyltriethoxysilane.

  The addition amount of the fluorine-containing compound is preferably 20% by mass or less based on the total amount of the protective layer 5. When the addition amount exceeds 20% by mass, there may be a problem in the film formability of the crosslinked cured film.

  Although the protective layer 5 has sufficient oxidation resistance, an antioxidant may be added for the purpose of imparting stronger oxidation resistance. Antioxidants are preferably hindered phenols or hindered amines, organic sulfur antioxidants, phosphite antioxidants, dithiocarbamate antioxidants, thiourea antioxidants, benzimidazole antioxidants. You may use well-known antioxidants, such as. As addition amount of antioxidant, 15 mass% or less is preferable on the basis of the protective layer 5 whole quantity, and 10 mass% or less is more preferable.

  Examples of the hindered phenol antioxidant include 2,6-di-t-butyl-4-methylphenol, 2,5-di-t-butylhydroquinone, N, N′-hexamethylene bis (3,5-di). -T-butyl-4-hydroxyhydrocinnamide, 3,5-di-t-butyl-4-hydroxy-benzylphosphonate-diethyl ester, 2,4-bis [(octylthio) methyl] -o-cresol, 2,6-di-t-butyl-4-ethylphenol, 2,2'-methylenebis (4-methyl-6-t-butylphenol), 2,2'-methylenebis (4-ethyl-6-t-butylphenol) 4,4'-butylidenebis (3-methyl-6-t-butylphenol), 2,5-di-t-amylhydroquinone, 2-t-butyl-6- (3-butyl-2- Dorokishi-5-methylbenzyl) -4-methylphenyl acrylate, 4,4'-butylidene bis (3-methyl -6-t-butylphenol) and the like.

  It is also possible to add other additives used for forming a known coating film to the protective layer 5, and use known materials such as a leveling agent, an ultraviolet absorber, a light stabilizer, and a surfactant. it can.

  The protective layer 5 can be formed by applying a coating solution for forming a protective layer containing the various materials and various additives described above onto the photosensitive layer 3 and subjecting it to a heat treatment. Thereby, the compounds represented by the above general formulas (I) to (VI) undergo a cross-linking curing reaction three-dimensionally, and a firm cured film is formed. The temperature of the heat treatment is not particularly limited as long as it does not affect the underlying photosensitive layer 3, but is preferably set to room temperature to 200 ° C, more preferably 100 to 160 ° C.

  In the formation of the protective layer 5, the cross-linking curing reaction may be performed without a catalyst, or an appropriate catalyst may be used. Catalysts include acid catalysts such as hydrochloric acid, sulfuric acid, phosphoric acid, formic acid, acetic acid and trifluoroacetic acid, bases such as ammonia and triethylamine, organotin compounds such as dibutyltin diacetate, dibutyltin dioctoate and stannous oxalate, tetra -Organic titanium compounds such as -n-butyl titanate and tetraisopropyl titanate, iron salts, manganese salts, cobalt salts, zinc salts, zirconium salts and aluminum chelate compounds of organic carboxylic acids.

  In order to make application | coating easy, the solvent can be added to the coating liquid for protective layer formation as needed. Specific examples of the solvent include water, methanol, ethanol, n-propanol, i-propanol, n-butanol, benzyl alcohol, methyl cellosolve, ethyl cellosolve, acetone, methyl ethyl ketone, cyclohexanone, methyl acetate, n-butyl acetate, dioxane, Examples include ordinary organic solvents such as tetrahydrofuran, methylene chloride, chloroform, dimethyl ether, dibutyl ether and the like. These can be used individually by 1 type or in mixture of 2 or more types.

  In the formation of the protective layer 5, the application method of the coating liquid for forming the protective layer includes blade coating method, wire bar coating method, spray coating method, dip coating method, bead coating method, air knife coating method, curtain coating method, etc. Conventional methods can be used.

  The thickness of the protective layer 5 is preferably 0.5 to 20 μm, and more preferably 2 to 10 μm.

  In the electrophotographic photoreceptor 100, the thickness of the functional layer above the charge generation layer 31 is preferably 50 μm or less, and more preferably 40 μm or less, from the viewpoint of obtaining higher resolution. When the functional layer is a thin film, the combination of the particle-dispersed undercoat layer 2 and the high-strength protective layer 5 described above is particularly effectively used.

  The preferred embodiment of the electrophotographic photoreceptor of the present invention has been described in detail above, but the electrophotographic photoreceptor of the present invention is not limited to the above embodiment. For example, the electrophotographic photosensitive member of the present invention has a structure in which an undercoat layer 2 and a photosensitive layer 3 are sequentially laminated on a conductive substrate 1 like an electrophotographic photosensitive member 110 shown in FIG. Also good. 3 may have a structure in which the undercoat layer 2 and the single-layer type photosensitive layer 6 are sequentially laminated on the conductive substrate 1.

  As described above, the electrophotographic photoreceptor of the present invention only needs to have the undercoat layer having the above-described structure between the conductive substrate and the photosensitive layer, and the photosensitive layer includes the charge generation material and the charge transport material. A single-layer type photosensitive layer contained in the same layer, or a function-separated type photosensitive layer in which a layer containing a charge generation material (charge generation layer) and a layer containing a charge transport material (charge transport layer) are separately provided Either may be sufficient. In the case of the function-separated type photosensitive layer, any of the stacking order of the charge generation layer and the charge transport layer may be the upper layer. In the case of a function-separated photosensitive layer, it is possible to achieve functional separation because it is possible to perform functional separation in which each layer only has to satisfy each function. Further, the electrophotographic photosensitive member 110 shown in FIG. 2 and the electrophotographic photosensitive member 120 shown in FIG. 3 may further have a protective layer 5 and an intermediate layer 4, respectively.

  When the charge transport layer 32 is the outermost surface layer of the photoreceptor (a layer disposed on the side farthest from the conductive substrate 1) as in the electrophotographic photoreceptor 110 shown in FIG. Lubricant particles (for example, silica particles, alumina particles, etc.) are used to impart lubricity, make the surface layer less likely to be worn or scratched, and to improve the cleaning properties of the developer attached to the photoreceptor surface. And fluorine-based resin particles such as polytetrafluoroethylene (PTFE) and silicone-based resin particles). These lubricating particles can be used in combination of two or more. In particular, fluorine resin particles are preferably used.

  Fluorine-based resin particles include tetrafluoroethylene resin, trifluorinated ethylene resin, hexafluoropropylene resin, vinyl fluoride resin, vinylidene fluoride resin, difluorodiethylene chloride resin and copolymers thereof. It is desirable to appropriately select one or two or more kinds from among them, and particularly preferred are tetrafluoroethylene resin and vinylidene fluoride resin.

  The average primary particle size of the fluorine-based resin particles is preferably 0.05 to 1 μm, and more preferably 0.1 to 0.5 μm. When the average primary particle size is less than 0.05 μm, aggregation tends to proceed at the time of dispersion or after dispersion. On the other hand, if it exceeds 1 μm, image quality defects tend to occur.

  When adding fluorine resin particles to the charge transport layer 32, the content of the fluorine resin particles in the charge transport layer 32 is suitably 0.1 to 40% by mass based on the total amount of the charge transport layer 32, 1-30 mass% is more preferable. If the content is less than 0.1% by mass, the modification effect due to the dispersion of the fluororesin particles tends to be insufficient. On the other hand, if the content exceeds 40% by mass, the light transmission property decreases and the residual potential due to repeated use is reduced. There is a tendency to increase.

  As a method of dispersing the fluorine resin particles in the coating liquid for forming the charge transport layer, a roll mill, a ball mill, a vibrating ball mill, an attritor, a sand mill, a high-pressure homogenizer, an ultrasonic disperser, a colloid mill, a collision-type medialess disperser, A method such as a through-type medialess disperser can be used.

  Examples of the dispersion of the coating solution for forming the charge transport layer include a method of dispersing the fluorine-based resin particles in a solution of a binder resin, a charge transport material and the like dissolved in a solvent.

  In the step of producing the charge transport layer forming coating solution, the temperature of the coating solution is preferably controlled in the range of 0 ° C to 50 ° C. As a method of controlling the temperature of the coating liquid in the coating liquid manufacturing process to 0 ° C. to 50 ° C., cool with water, cool with wind, cool with refrigerant, adjust the room temperature of the manufacturing process, warm with warm water, warm with hot air It is possible to use methods such as heating with a heater, creating a coating liquid manufacturing facility with a material that does not easily generate heat, creating a coating liquid manufacturing facility with a material that easily dissipates heat, or creating a coating liquid manufacturing facility with a material that easily stores heat.

  It is also effective to add a small amount of a dispersion aid to the coating solution in order to improve the dispersion stability of the coating solution for forming the charge transport layer and to prevent aggregation during the formation of the coating film. Examples of the dispersion aid include a fluorine-based surfactant, a fluorine-based polymer, a silicone-based polymer, and a silicone oil. In addition, after dispersing, stirring, and mixing these dispersion aids and fluorine resin particles in a small amount of a dispersion solvent in advance, stirring and mixing with a solution in which the charge transport material, the binder resin, and the dispersion solvent are mixed and dissolved. Dispersing by the above-described method is also an effective means.

  The electrophotographic photoreceptor of the present invention described above exhibits stable electrical characteristics (cycle stability) even when used repeatedly, and sufficiently suppresses the occurrence of image quality defects such as fogging, black spots, and ghosts. can do.

(Image forming apparatus and process cartridge)
Next, an image forming apparatus and a process cartridge equipped with the electrophotographic photosensitive member of the present invention will be described.

  FIG. 4 is a schematic cross-sectional view showing a preferred embodiment of the image forming apparatus of the present invention. An image forming apparatus 200 shown in FIG. 4 includes a drum-shaped (cylindrical) electrophotographic photosensitive member 7 of the present invention that is rotatably provided. Around the electrophotographic photosensitive member 7, a charging device 8, an exposure device 10, a developing device 11, a transfer device 12, a cleaning device 13, and a static eliminator (erase) are arranged along the movement direction of the outer peripheral surface of the electrophotographic photosensitive member 7. Device) 14 are arranged in this order.

  The charging device 8 is a corona charging method charging device that is a non-contact charging method, and charges the electrophotographic photoreceptor 7. Examples of the charging device 8 include a corotron charger and a scorotron charger. The charging device 8 is connected to a power source 9.

  The exposure device 10 exposes the charged electrophotographic photosensitive member 7 to form an electrostatic latent image on the electrophotographic photosensitive member 7.

  The developing device 11 develops the electrostatic latent image with a developer to form a toner image. The developer preferably contains toner particles having a volume average particle diameter of 3 to 9 μm obtained by a polymerization method.

  The transfer device 12 transfers the toner image developed on the electrophotographic photosensitive member 7 to the transfer medium 20.

  The cleaning device 13 removes toner remaining on the electrophotographic photosensitive member 7 after transfer. The cleaning device 13 preferably has a blade member that comes into contact with the electrophotographic photoreceptor 7 at a linear pressure of 10 to 150 g / cm.

  The static eliminator (erase device) 14 erases the remaining charges on the electrophotographic photosensitive member 7.

  Further, the image forming apparatus 200 includes a fixing device 15 that fixes the toner image on the transfer medium after the transfer process.

  FIG. 5 is a schematic cross-sectional view showing another preferred embodiment of the image forming apparatus of the present invention. An image forming apparatus 210 shown in FIG. 5 has the same configuration as that of the image forming apparatus 200 shown in FIG. 4 except that it includes a charging device 8 that charges the electrophotographic photoreceptor 7 by a contact charging method. In particular, in the image forming apparatus 210 that employs a contact-type charging device in which an AC voltage is superimposed on a DC voltage, the electrophotographic photosensitive member 7 can be preferably used because it has excellent leakage resistance. In this case, the static eliminator 14 may not be provided.

  In the contact charging method, charging members such as a roller shape, a blade shape, a belt shape, a brush shape, and a magnetic brush shape are applicable. In particular, the roller-like or blade-like charging member may be arranged in a contact state or a non-contact state having a certain amount of gaps (100 μm or less) with respect to the electrophotographic photoreceptor 7.

A roller-shaped charging member, a blade-shaped charging member, and a belt-shaped charging member are composed of materials adjusted to an electric resistance (1 × 10 ³ Ω to 1 × 10 ⁸ Ω) effective as a charging member. It may be composed of a single layer or a plurality of layers.

  The material of the charging member is mainly composed of synthetic rubber such as urethane rubber, silicon rubber, fluorine rubber, chloroprene rubber, butadiene rubber, EPDM, epichlorohydrin rubber, and elastomers such as polyolefin, polystyrene, vinyl chloride, conductive carbon, An appropriate electrical conductivity imparting agent such as a metal oxide or an ionic conductive agent can be blended in an appropriate amount to develop an effective electrical resistance as a charging member.

  Furthermore, a paint obtained by converting a resin such as nylon, polyester, polystyrene, polyurethane, silicone, etc. into a paint, and blending an appropriate amount of any conductivity imparting agent such as conductive carbon, metal oxide, ionic conductive agent, It can be used by laminating by any method such as dipping, spraying, roll coating and the like.

  On the other hand, for brush-shaped charging members, a conventional fiber-impregnated fiber such as acrylic, nylon, polyester, etc., is impregnated with fluorine, and then transplanted using an existing method, and brush-shaped charging is performed. A member can be produced. Further, after various fibers are formed on the brush-shaped charging member, fluorine impregnation treatment may be performed.

  The brush-shaped charging member referred to here may be any of a roller-shaped charging member and a brushed charging member, and the shape thereof is not particularly limited. Further, the magnetic brush-like charging member is a magnetically arranged ferrite, magite, etc., radially arranged on the outer periphery of the cylinder containing the multipolar magnet, and after pre-applied fluorine, magite, etc. A magnetic brush is desirable.

  FIG. 6 is a schematic cross-sectional view showing another preferred embodiment of the image forming apparatus of the present invention. The image forming apparatus 220 is an image forming apparatus of a tandem type intermediate transfer system. In the housing 400, four electrophotographic photosensitive members 401a to 401d (for example, 401a is yellow, 401b is magenta, 401c is cyan, 401d is black). Color images can be formed respectively) along the intermediate transfer belt 409 and arranged in parallel with each other.

  Conventionally, as a method for transferring a visible image onto a transfer paper such as paper, a transfer drum method for winding a transfer paper such as paper around a transfer drum and transferring the visible image on the photosensitive member to the transfer paper for each color, etc. It has been known. In this case, compared with the tandem intermediate transfer method, the transfer of the visible image from the photosensitive member to the intermediate transfer member had to rotate the intermediate transfer member a plurality of times. This is a promising transfer method in the future because it can be transferred from a plurality of photoconductors 401a to 401d by making one rotation 409, and transfer speed can be improved, and a transfer medium can be selected as in the transfer drum method. .

  Here, the electrophotographic photoreceptors 401 a to 401 d mounted on the image forming apparatus 220 are the same as the electrophotographic photoreceptor 7.

  Each of the electrophotographic photosensitive members 401a to 401d can be rotated in a predetermined direction (counterclockwise on the paper surface), and the charging rolls 402a to 402d, the developing devices 404a to 404d, and the primary transfer roll 410a along the rotation direction. To 410d and cleaning devices 415a to 415d are arranged. Each of the developing devices 404a to 404d can be supplied with toners of four colors, yellow, magenta, cyan, and black accommodated in toner cartridges 405a to 405d. Further, the primary transfer rolls 410a to 410d are in contact with the electrophotographic photosensitive members 401a to 401d via the intermediate transfer belt 409, respectively.

  Further, a laser light source (exposure device) 403 is disposed at a predetermined position in the housing 400. Laser light emitted from the laser light source 403 can be applied to the surfaces of the charged electrophotographic photoreceptors 401a to 401d. Accordingly, charging, exposure, development, primary transfer, and cleaning are sequentially performed in the rotation process of the electrophotographic photosensitive members 401a to 401d, and the toner images of the respective colors are transferred onto the intermediate transfer belt 409 in an overlapping manner.

  The intermediate transfer belt 409 is supported with a predetermined tension by a drive roll 406, a backup roll 408, and a tension roll 407, and can rotate without causing deflection due to the rotation of these rolls. Further, the secondary transfer roll 413 is disposed so as to contact the backup roll 408 via the intermediate transfer belt 409. The intermediate transfer belt 409 passing between the backup roll 408 and the secondary transfer roll 413 is cleaned by, for example, a cleaning blade 416 disposed in the vicinity of the drive roll 406 and then repeatedly used for the next image forming process. Is done.

  A tray (transfer medium tray) 411 is provided at a predetermined position in the housing 400, and the transfer medium 500 such as paper in the tray 411 is moved by the intermediate transfer belt 409 and the secondary transfer roll by the transfer roll 412. Then, the paper is sequentially transferred between the two fixing rolls 414 that are in contact with each other and the two fixing rolls 414, and then discharged to the outside of the housing 400.

  In the above description, the case where the intermediate transfer belt 409 is used as the intermediate transfer member has been described. However, the intermediate transfer member may have a belt shape (for example, an endless belt shape) like the intermediate transfer belt 409. It may be a drum shape. When a belt-shaped configuration such as the intermediate transfer belt 409 is employed as the intermediate transfer member, generally the film thickness of the belt is preferably 50 to 500 μm, and more preferably 60 to 150 μm. In addition, the film thickness of a belt can be suitably selected according to the hardness of material. When a drum-shaped configuration is adopted as the intermediate transfer member, it is preferable to use a cylindrical substrate formed of aluminum, stainless steel (SUS), copper, or the like as the substrate. If necessary, an elastic layer can be coated on the cylindrical substrate, and a surface layer can be formed on the elastic layer.

  The transfer medium referred to in the present invention is not particularly limited as long as it is a medium for transferring a toner image formed on an electrophotographic photosensitive member. For example, when transferring directly from an electrophotographic photosensitive member to paper or the like, paper or the like is a transfer medium, and when an intermediate transfer member is used, the intermediate transfer member is a transfer medium.

  As the material of the endless belt, heat such as polycarbonate resin (PC), polyvinylidene fluoride (PVDF), polyalkylene phthalate, PC / polyalkylene phthalate (PAT) blend material, ethylene tetrafluoroethylene copolymer (ETFE), etc. A semiconductive endless belt made of a plastic resin has been proposed.

  Japanese Patent No. 2560727, Japanese Patent Application Laid-Open No. 5-77252, etc. propose an intermediate transfer member in which ordinary carbon black is dispersed as a conductive fine powder in a polyimide resin.

  Since the polyimide resin is a material having a high Young's modulus, it is less likely to be deformed by driving (stress of a support roll, a cleaning blade, etc.), so that it becomes an intermediate transfer body in which image defects such as color misregistration are unlikely to occur. A polyimide resin is usually obtained as a polyamic acid solution by polymerizing a substantially equimolar amount of tetracarboxylic dianhydride or its derivative and a diamine in a solvent. As tetracarboxylic dianhydride, what is shown by the following general formula (XV) is mentioned, for example.

［式中、Ｒは、脂肪族鎖式炭化水素基、脂肪族環式炭化水素基及び芳香族炭化水素基、並びにこれらの炭化水素基に置換基が結合した基からなる群より選ばれる４価の有機基を示す。］

[Wherein, R is a tetravalent group selected from the group consisting of an aliphatic chain hydrocarbon group, an aliphatic cyclic hydrocarbon group, an aromatic hydrocarbon group, and a group in which a substituent is bonded to these hydrocarbon groups. An organic group of ]

  Specific examples of the tetracarboxylic dianhydride include pyromellitic dianhydride, 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride, and 3,3 ′, 4,4′-biphenyltetracarboxylic acid. Acid dianhydride, 2,3,3 ′, 4-biphenyltetracarboxylic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 1,2,5,6-naphthalenetetracarboxylic acid Dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, 2,2′-bis (3,4-dicarboxyphenyl) sulfonic dianhydride, perylene-3,4,9,10 -Tetracarboxylic dianhydride, bis (3,4-dicarboxyphenyl) ether dianhydride, ethylenetetracarboxylic dianhydride, etc. are mentioned.

On the other hand, specific examples of the diamine include 4,4′-diaminodiphenyl ether, 4,4′-diaminodiphenylmethane, 3,3′-diaminodiphenylmethane, 3,3′-dichlorobenzidine, 4,4′-diaminodiphenyl sulfide, 3,3′-diaminodiphenylsulfone, 1,5-diaminonaphthalene, m-phenylenediamine, p-phenylenediamine, 3,3′-dimethyl-4,4′-biphenyldiamine, benzidine, 3,3′-dimethylbenzidine 3,3′-dimethoxybenzidine, 4,4′-diaminodiphenylsulfone, 4,4′-diaminodiphenylpropane, 2,4-bis (β-aminotert-butyl) toluene, bis (p-β-amino- Tert-butylphenyl) ether, bis (p-β-methyl-δ-aminophenyl) benzene, bis p- (1,1-dimethyl-5-amino-benzyl) benzene, 1-isopropyl-2,4-m-phenylenediamine, m-xylylenediamine, p-xylylenediamine, di (p-aminocyclohexyl) methane , Hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, decamethylenediamine, diaminopropyltetramethylene, 3-methylheptamethylenediamine, 4,4-dimethylheptamethylenediamine, 2,11-diaminododecane, 1 , 2-bis-3-aminopropoxyethane, 2,2-dimethylpropylenediamine, 3-methoxyhexamethylenediamine, 2,5-dimethylheptamethylenediamine, 3-methylheptamethylenediamine, 5-methylnonamethylenediamine, 2, 17-diaminoeicosadecane, 1,4-diaminocyclohexane, 1,10-diamino-1,10-dimethyldecane, 12-diaminooctadecane, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, _{piperazine, H 2 N (CH 2)} 3 O (CH 2) 2 O (CH 2) NH 2, H 2 N (CH 2) 3 S (CH 2) 3 NH 2, H 2 N (CH 2) 3 N _{(CH 3) 2 (CH 2} ) 3 NH 2 and the like.

  As the solvent for the polymerization reaction of tetracarboxylic dianhydride and diamine, a polar solvent is preferably used from the viewpoint of solubility. As the polar solvent, N, N-dialkylamides are preferable, and specific examples thereof include N, N-dimethylformamide, N, N-dimethylacetamide, N, N-diethylformamide, which are low molecular weight compounds thereof. N, N-diethylacetamide, N, N-dimethylmethoxyacetamide, dimethyl sulfoxide, hexamethylphosphortriamide, N-methyl-2-pyrrolidone, pyridine, tetramethylenesulfone, dimethyltetramethylenesulfone and the like. These can be used individually by 1 type or in combination of 2 or more types.

  The intermediate transfer member contains oxidized carbon black in a polyimide resin. Oxidized carbon black can be obtained by oxidizing carbon black to give an oxygen-containing functional group (for example, carboxyl group, quinone group, lactone group, hydroxyl group, etc.) to the surface.

  This oxidation treatment is an air oxidation method in which contact is caused to react with air in a high temperature atmosphere, a method in which it reacts with nitrogen oxide or ozone at room temperature, and a method in which ozone oxidation is performed at low temperature after air oxidation at high temperature. Etc.

  Specific examples of the oxidized carbon include MA100 (pH 3.5, volatile matter 1.5%), MA100R (pH 3.5, volatile matter 1.5%), and MA100S (pH 3.5, volatile matter) manufactured by Mitsubishi Chemical. 1.5%), # 970 (pH 3.5, volatile content 3.0%), MA11 (pH 3.5, volatile content 2.0%), # 1000 (pH 3.5, volatile content 3.). 0%), # 2200 (pH 3.5, volatile content 3.5%), MA 230 (pH 3.0, volatile content 1.5%), MA 220 (pH 3.0, volatile content 1.0%), # 2650 (pH 3.0, volatile content 8.0%), MA7 (pH 3.0, volatile content 3.0%), MA8 (pH 3.0, volatile content 3.0%), OIL7B (pH 3) 0.0, volatile content 6.0%), MA77 (pH 2.5, volatile content 3.0%), # 2350 (pH) .5, volatile content 7.5%), # 2700 (pH 2.5, volatile content 10.0%), # 2400 (pH 2.5, volatile content 9.0%), Dexa Printex 150T (PH 4.5, volatile content 10.0%), Special Black 350 (pH 3.5, volatile content 2.2%), Special Black 100 (pH 3.3, volatile content 2.2%), Special Black 250 (pH 3.1, volatile content 2.0%), Special Black 5 (pH 3.0, volatile content 15.0%), Special Black 4 (pH 3.0, volatile content 14.0%), Special Black 4A (pH 3.0, volatile content 14.0%), Special Black 550 (pH 2.8, volatile content 2.5%), Special Black 6 (pH 2.5, volatile content 18.0%), Color black FW20 (PH 2.5, volatile content 20.0%), same color black FW2 (pH 2.5, volatile content 16.5%), same color black FW2V (pH 2.5, volatile content 16.5%), manufactured by Cabot Corporation MONARCH 1000 (pH 2.5, volatile content 9.5%), MONARCH 1300 (pH 2.5, volatile content 9.5%) manufactured by Cabot, MONARCH 1400 (pH 2.5, volatile content 9.0%) manufactured by Cabot, MOGUL -L (pH 2.5, volatile matter 5.0%), REGAL400R (pH 4.0, volatile matter 3.5%) and the like.

  The oxidation-treated carbon black obtained in this way has an excessive current flowing in part, and is not easily affected by oxidation due to repeated voltage application. Furthermore, due to the effect of the oxygen-containing functional group attached to the surface, the dispersibility in polyimide is high, the resistance variation can be reduced, the electric field dependency is also reduced, and the electric field concentration due to the transfer voltage is less likely to occur. .

  As a result, resistance degradation due to transfer voltage is prevented, uniformity of electrical resistance is improved, electric field dependency is small, resistance change due to the environment is small, and image quality defects such as whitening of the paper running part occur. The intermediate transfer member can obtain a suppressed high image quality. When two or more kinds of oxidized carbon blacks are added, these oxidized carbon blacks are preferably substantially different in conductivity from each other. For example, the BET method utilizing the degree of oxidation treatment, DBP oil absorption, and nitrogen adsorption Those having different physical properties such as specific surface area are used. When two or more types of carbon blacks having different physical properties are added as described above, for example, carbon black exhibiting high conductivity is preferentially added, and then carbon black having low conductivity is added to adjust the surface resistivity. It is possible.

  Specific examples of the oxidized carbon black include SPECIAL BLACK4 (Degussa, pH 3.0, volatile content: 14.0%), SPECIAL BLACK250 (Degussa, pH 3.1, volatile content: 2.0%), and the like. Is mentioned. The content of these oxidized carbon blacks is preferably about 10 to 50% by mass, more preferably 12 to 30% by mass with respect to the polyimide resin. If this content is less than 10% by mass, the uniformity of electrical resistance may be reduced, and the decrease in surface resistivity during durable use may increase. On the other hand, if it exceeds 50% by mass, the desired resistance value may be obtained. Is not preferred, and it is not preferable because it becomes brittle as a molded product.

  The intermediate transfer body made of polyimide resin in which oxidized carbon black is dispersed performs a step of preparing a polyamic acid solution in which oxidized carbon black is dispersed, a step of forming a film (layer) on the inner surface of a cylindrical mold, and imide conversion It can be obtained through a process.

  About the manufacturing method of the polyamic acid solution which disperse | distributed 2 or more types of oxidation treatment carbon black, the said acid dianhydride component and diamine component are contained in the dispersion liquid which disperse | distributed 2 or more types of oxidation treatment carbon black beforehand in the solvent. Method of dissolving and polymerizing Two or more types of oxidized carbon black are each dispersed in a solvent to prepare two or more types of carbon black dispersions, and the acid anhydride component and the diamine component are dissolved and polymerized in this dispersion. Thereafter, a method of mixing each polyamic acid solution, etc. can be considered, and a polyamic acid solution in which carbon black is dispersed is prepared by selecting as appropriate.

  The intermediate transfer member is obtained by supplying and spreading the polyamic acid solution thus obtained on the inner surface of the cylindrical mold to form a coating film, and converting the polyamic acid to imide by heating. In this imide conversion, an intermediate transfer member having good flatness can be obtained by holding at a predetermined temperature for 0.5 hour or more.

  Examples of a supply method for supplying the polyamic acid solution to the inner surface of the cylindrical mold include a method using a dispenser and a method using a die. Here, as the cylindrical mold, it is preferable to use a mirror-finished inner peripheral surface.

  Examples of the method of forming a film from the polyamic acid solution supplied to the mold include a method of centrifugal molding while heating, a method of molding using a bullet-shaped traveling body, a method of rotational molding, and the like. A film having a uniform film thickness is formed by the method.

  The method for forming the intermediate transfer body by converting the thus formed film into an imide is (i) a method in which the mold is placed in a dryer and the temperature is raised to a reaction temperature for imide conversion, and (ii) a belt. As a method, after removing the solvent until the shape can be maintained, the film is peeled off from the inner surface of the mold and replaced with the outer surface of the metal cylinder, and then the imide conversion is performed by heating the entire cylinder. In order to obtain an intermediate transfer member having good flatness and outer surface accuracy, the method (ii) described above, in which the solvent is removed until it can be held as a belt, and then replaced with a metal cylinder for imide conversion.

  In the above method (ii), the heating conditions for removing the solvent are not particularly limited as long as the solvent can be removed, but the heating temperature is preferably 80 to 200 ° C., and the heating time is 0.5 to 5 hours. It is preferable. In this way, the molded product that can retain its shape as a belt is peeled off from the inner peripheral surface of the mold. At this time, a mold release process can be performed on the inner peripheral surface of the mold.

  Next, the molded product heated and cured until it can be held as a belt shape is replaced with the outer surface of the metal cylinder, and the replaced cylinder is heated to advance the imide conversion reaction of the polyamic acid. As such a metal cylinder, one having a linear expansion coefficient larger than that of polyimide resin is preferable, and by setting the outer diameter of the cylinder to be a predetermined amount smaller than the inner diameter of the polyimide molding, a uniform film can be formed. An endless belt having a uniform thickness can be obtained. Moreover, it is preferable that the surface roughness (Ra) of a metal cylinder outer surface is 1.2-2.0 micrometers. When the surface roughness (Ra) of the outer surface of the metal cylinder is less than 1.2 μm, the metal cylinder itself is too smooth, and the resulting intermediate transfer body does not slip due to contraction in the axial direction of the belt. This process is performed, and there may be a case where film thickness variation and flatness accuracy decrease. If the surface roughness (Ra) of the outer surface of the metal cylinder exceeds 2.0 μm, the outer surface of the metal cylinder is transferred to the inner surface of the belt-shaped intermediate transfer body, and further, irregularities are generated on the outer surface. May be more likely to occur. In addition, the surface roughness as used in the field of this invention means Ra measured according to JISB601.

  Moreover, although it is based also on a composition of a polyimide resin as a heating condition in the case of imide conversion, it is preferable that heating temperature is 220-280 degreeC and heating time is 0.5 to 2 hours. When imide conversion is performed under such heating conditions, the amount of shrinkage of the polyimide resin becomes larger, and therefore, the shrinkage in the axial direction of the belt is gently performed to prevent a decrease in film thickness variation and flatness accuracy. Can do.

  The surface roughness (Ra) of the outer surface of the intermediate transfer member made of the polyimide resin thus obtained is preferably 1.5 μm or less. When the surface roughness (Ra) of the intermediate transfer member exceeds 1.5 μm, image defects such as roughness are likely to occur. Note that the occurrence of roughness is a resistance caused by the appearance of a new conductive path due to the voltage applied during transfer and the electric field due to the peeling discharge being locally concentrated on the convex portion of the belt surface and deteriorating the convex surface. Is considered to be caused by a decrease in the density of the resulting image.

  The intermediate transfer member thus obtained has a flatness of 5 mm or less, preferably 3 mm or less. When the flatness is 5 mm or less, there is no roughness and color deviation is small. However, when the belt end portion is bent vertically, even if the flatness is 5 mm or less, it does not break during use of the intermediate transfer member, but it rarely remains after contacting the peripheral member. Further, when the flatness is 3 mm or less, the intermediate transfer member is not brought into contact with the peripheral member during use and there is almost no color shift.

  FIG. 7 is a schematic cross-sectional view showing a preferred embodiment of the process cartridge of the present invention. The process cartridge 300 is integrated with the electrophotographic photosensitive member 7 of the present invention by combining the charging unit 8, the developing unit 11, the cleaning unit 13, the opening 18 for exposure, and the static eliminator 14 using the mounting rail 16. It is a thing. The process cartridge 300 is detachable from the main body of the image forming apparatus including the transfer unit 12, the fixing unit 15, and other components (not shown). It constitutes. Such a process cartridge 300 can be applied to any of the image forming apparatuses shown in FIGS.

  According to the image forming apparatus and the process cartridge of the present invention, since the electrophotographic photosensitive member of the present invention is used, it is possible to stably form an image with good image quality over a long period of time.

  EXAMPLES Hereinafter, although this invention is demonstrated more concretely based on an Example and a comparative example, this invention is not limited to a following example.

(Example 1)
100 parts by mass of zinc oxide (Taika, average particle size 70 nm, specific surface area value 15 m ² / g) is stirred and mixed with 500 parts by mass of tetrahydrofuran, and silane coupling agent (KBM603, manufactured by Shin-Etsu Chemical Co., Ltd.) 1.25 parts by mass. Was added and stirred for 2 hours. Thereafter, toluene was distilled off under reduced pressure and baked at 120 ° C. for 3 hours to obtain a surface-treated zinc oxide pigment.

  Next, alizarin (manufactured by Nagase Sangyo Co., Ltd.) which is an electron accepting substance and alizarin sulfonate represented by the following formula (XVI) which is an ionic substance are mixed at a ratio of 95: 5 (mass ratio). After stirring for 5 minutes at room temperature in a solvent (MEK), MEK was removed to obtain a mixture. 0.3 parts by mass of the obtained mixture, 60 parts by mass of the surface-treated zinc oxide pigment, 13.5 parts by mass of blocked isocyanate (Sumidule 3175, manufactured by Sumitomo Bayern Urethane Co., Ltd.) as a curing agent, and butyral resin ( BM-1 (manufactured by Sekisui Chemical Co., Ltd.) 10 parts by mass in a mixed solvent of 72 parts by mass of methyl ethyl ketone and 18 parts by mass of n-hexane 2 parts by sand mill using 1 mmφ glass beads. Time dispersion was performed to obtain a dispersion.

  To the obtained dispersion, 0.005 parts by mass of dioctyltin dilaurate as a catalyst and 4.0 parts by mass of silicone resin particles (Tospearl 145, manufactured by GE Toshiba Silicone) are added, and the coating for forming the undercoat layer is performed. A liquid was obtained. This coating solution was applied onto an aluminum substrate by a dip coating method, followed by drying and curing at 170 ° C. for 40 minutes to form an undercoat layer having a thickness of 25 μm.

  Next, at a Bragg angle (2θ ± 0.2 °) of an X-ray diffraction spectrum using a Cukα ray as a charge generation material, at least 7.3 °, 16.0 °, 24.9 °, 28.0 From 15 parts by mass of hydroxygallium phthalocyanine having a diffraction peak at a position of 10 parts by mass of vinyl chloride-vinyl acetate copolymer resin (VMCH, manufactured by Nihon Unicar) as a binder resin, and 200 parts by mass of n-butyl acetate The resulting mixture was dispersed in a sand mill for 4 hours using 1 mmφ glass beads. To the obtained dispersion, 175 parts by mass of n-butyl acetate and 180 parts by mass of methyl ethyl ketone were added and stirred to obtain a coating solution for forming a charge generation layer. The obtained coating solution was dip-coated on the undercoat layer and dried at room temperature to form a charge generation layer having a thickness of 0.2 μm.

Next, 1 part by mass of tetrafluoroethylene resin particles and 0.02 part by mass of the fluorine-based graft polymer were sufficiently stirred and mixed together with 5 parts by mass of tetrahydrofuran and 2 parts by mass of toluene, to obtain tetrafluoroethylene resin particles. A suspension was obtained. Next, 4 parts by mass of N, N′-diphenyl-N, N′-bis (3-methylphenyl)-[1,1 ′] biphenyl-4,4′-diamine as a charge transport material, and bisphenol Z In the solution obtained by dissolving 6 parts by mass of a polycarbonate resin (viscosity average molecular weight 40,000) in a mixed solvent of 23 parts by mass of tetrahydrofuran and 10 parts by mass of toluene, the above tetrafluoroethylene resin particle suspension Is added and stirred and mixed, and then the dispersion process is repeated 6 times by increasing the pressure to 400 kgf / cm ² using a high-pressure homogenizer (LA-33S, manufactured by Nanomizer) equipped with a through-type chamber having fine flow paths. A tetrafluoroethylene resin particle dispersion was obtained. Further, 0.2 part by mass of 2,6-di-t-butyl-4-methylphenol was mixed with this dispersion to obtain a coating liquid for forming a charge transport layer. This coating solution was applied onto the charge generation layer and dried at 115 ° C. for 40 minutes to form a charge transport layer having a thickness of 32 μm. Thus, the intended electrophotographic photosensitive member was obtained.

(Example 2)
Except that the mixing ratio of alizarin (manufactured by Nagase Sangyo Co., Ltd.), which is an electron acceptor, and alizarin sulfonate represented by the above formula (XVI), which is an ionic substance, is 90:10 (mass ratio). In the same manner as in Example 1, an electrophotographic photosensitive member was obtained.

(Example 3)
Except that the mixing ratio of alizarin (manufactured by Nagase Sangyo Co., Ltd.), which is an electron accepting substance, and the sulfonate salt of alizarin represented by the above formula (XVI), which is an ionic substance, is 85:15 (mass ratio). In the same manner as in Example 1, an electrophotographic photosensitive member was obtained.

Example 4
First, in the same manner as in Example 1, a surface-treated zinc oxide pigment was obtained. Next, 0.285 parts by mass of alizarin (manufactured by Nagase Sangyo Co., Ltd.) as an electron accepting substance, 0.015 parts by mass of sulfonate of alizarin represented by the above formula (XVI) as an ionic substance, and the surface 60 parts by mass of treated zinc oxide pigment, 13.5 parts by mass of blocked isocyanate (Sumidule 3175, manufactured by Sumitomo Bayern Urethane Co., Ltd.) as a curing agent, and 10 parts by mass of butyral resin (BM-1, manufactured by Sekisui Chemical Co., Ltd.) Was dissolved in a mixed solvent of 72 parts by mass of methyl ethyl ketone and 18 parts by mass of n-hexane to perform dispersion for 2 hours with a sand mill using 1 mmφ glass beads to obtain a dispersion. To the obtained dispersion, 0.005 parts by mass of dioctyltin dilaurate as a catalyst and 4.0 parts by mass of silicone resin particles (Tospearl 145, manufactured by GE Toshiba Silicone) are added, and the coating for forming the undercoat layer is performed. A liquid was obtained. This coating solution was applied onto an aluminum substrate by a dip coating method, followed by drying and curing at 170 ° C. for 40 minutes to form an undercoat layer having a thickness of 25 μm.

  Thereafter, in the same manner as in Example 1, a charge generation layer and a charge transport layer were sequentially formed to obtain a target electrophotographic photosensitive member.

(Example 5)
Instead of alizarin, which is an electron accepting substance, and alizarin sulfonate (mass ratio 95: 5) represented by the above formula (XVI), which is an ionic substance, it is represented by the following formula (XVII), which is an electron accepting substance. An electrophotographic photosensitive member was obtained in the same manner as in Example 1 except that BCFM and a BCFM sulfonate (mass ratio 95: 5) represented by the following formula (XVIII) which is an ionic substance were used. .

(Example 6)
Example 1 except that alizarin nitrate represented by the following formula (XIX), which is an ionic substance, was used instead of alizarin sulfonate represented by the above formula (XVI), which is an ionic substance. Similarly, an electrophotographic photoreceptor was obtained.

(Example 7)
Instead of alizarin, which is an electron accepting substance, and sulfonic acid salt of alizarin represented by the above formula (XVI), which is an ionic substance (mass ratio 95: 5), alizarin, which is an electron accepting substance, and the above, which is an ionic substance. An electrophotographic photosensitive member was obtained in the same manner as in Example 1 except that alizarin nitrate represented by the formula (XIX) (mass ratio 90:10) was used.

(Example 8)
Example 1 except that alizarin carbonate represented by the following formula (XX) as an ionic substance was used instead of alizarin sulfonate represented by the above formula (XVI) as an ionic substance. In the same manner as above, an electrophotographic photoreceptor was obtained.

Example 9
Instead of alizarin, which is an electron accepting substance, and sulfonic acid salt of alizarin represented by the above formula (XVI), which is an ionic substance (mass ratio 95: 5), alizarin, which is an electron accepting substance, and the above, which is an ionic substance. An electrophotographic photosensitive member was obtained in the same manner as in Example 1 except that alizarin carbonate represented by the formula (XX) (mass ratio 90:10) was used.

(Example 10)
Example except that alizarin phosphate represented by the following formula (XXI) as an ionic substance was used instead of alizarin sulfonate represented by the formula (XVI) as an ionic substance. In the same manner as in Example 1, an electrophotographic photosensitive member was obtained.

(Example 11)
Instead of alizarin, which is an electron accepting substance, and sulfonic acid salt of alizarin represented by the above formula (XVI), which is an ionic substance (mass ratio 95: 5), alizarin, which is an electron accepting substance, and the above, which is an ionic substance. An electrophotographic photosensitive member was obtained in the same manner as in Example 1 except that the phosphate (mass ratio 90:10) of alizarin represented by the formula (XXI) was used.

(Comparative Example 1)
First, in the same manner as in Example 1, a surface-treated zinc oxide pigment was obtained. Next, 0.3 part by mass of alizarin (manufactured by Nagase Sangyo Co., Ltd.) as an electron accepting substance, 60 parts by mass of the surface-treated zinc oxide pigment, and blocked isocyanate (Sumidule 3175, manufactured by Sumitomo Bayern Urethane Co., Ltd.) as a curing agent ) 57 parts by mass of a solution obtained by dissolving 13.5 parts by mass and 10 parts by mass of butyral resin (BM-1, manufactured by Sekisui Chemical Co., Ltd.) in a mixed solvent of 72 parts by mass of methyl ethyl ketone and 18 parts by mass of n-hexane, Dispersion was carried out for 2 hours with a sand mill using 1 mmφ glass beads to obtain a dispersion. To the obtained dispersion, 0.005 parts by mass of dioctyltin dilaurate as a catalyst and 4.0 parts by mass of silicone resin particles (Tospearl 145, manufactured by GE Toshiba Silicone) are added, and the coating for forming the undercoat layer is performed. A liquid was obtained. This coating solution was applied onto an aluminum substrate by a dip coating method, followed by drying and curing at 170 ° C. for 40 minutes to form an undercoat layer having a thickness of 25 μm.

  Thereafter, in the same manner as in Example 1, a charge generation layer and a charge transport layer were sequentially formed to obtain a target electrophotographic photosensitive member.

(Comparative Example 2)
Except that the mixture ratio of alizarin (manufactured by Nagase Sangyo Co., Ltd.), which is an electron accepting substance, and sulfonate salt of alizarin represented by the above formula (XVI), which is an ionic substance, is 98: 2 (mass ratio). In the same manner as in Example 1, an electrophotographic photosensitive member was obtained.

(Comparative Example 3)
Except that the mixing ratio of alizarin (manufactured by Nagase Sangyo Co., Ltd.), which is an electron accepting substance, and the sulfonate salt of alizarin represented by the above formula (XVI), which is an ionic substance, is 80:20 (mass ratio). In the same manner as in Example 1, an electrophotographic photosensitive member was obtained.

(Comparative Example 4)
Except that the mixing ratio of alizarin (manufactured by Nagase Sangyo Co., Ltd.), which is an electron accepting substance, and the sulfonate salt of alizarin represented by the above formula (XVI), which is an ionic substance, is 75:25 (mass ratio). In the same manner as in Example 1, an electrophotographic photosensitive member was obtained.

<Image formation test>
The electrophotographic photoreceptors obtained in Examples 1 to 11 and Comparative Examples 1 to 4 were mounted on a drum cartridge of a color copying machine Docu Center Color a450 (manufactured by Fuji Xerox Co., Ltd.) having a contact charging device and an intermediate transfer device. After performing an image formation test on 10,000 sheets in an environment of low temperature and low humidity (10 ° C., 20% RH), subsequently, forming an image of 10,000 sheets in an environment of high temperature and high humidity (28 ° C., 75% RH) Tested.

At this time, the potential after charging, exposure and static elimination on the electrophotographic photosensitive member is defined as the residual potential after static elimination (V _RP ), and after printing 10,000 sheets in a low temperature and low humidity environment with respect to the initial residual potential after static elimination. The amount of change in residual potential after static elimination (ΔV _RP ) and the amount of change in residual potential after static elimination after printing 10,000 sheets in a high-temperature and high-humidity environment (ΔV _RP ) were obtained, respectively, and cycle stability was evaluated. The results are shown in Table 7.

  In addition, the print image quality after printing 10,000 sheets under high temperature and high humidity and the print image quality after printing 10,000 sheets under low temperature and low humidity are visually observed, respectively, and the occurrence of ghost, fog and black spots The situation was evaluated according to the following evaluation criteria. The results are shown in Table 7.

(Ghost evaluation)
A: No ghost defect,
B: An extremely slight ghost defect occurs.
C: Minor ghost defect occurrence,
D: Ghost defect occurred.

(Evaluation of fog and sunspot)
A: No fogging and sunspot defects
B: Very slight fogging and black spot defect occurrence,
C: Minor fog and sunspot defect occurrence,
D: Fog and black spot defect occurred.

  As is apparent from the results shown in Table 7, according to the electrophotographic photoreceptors of Examples 1 to 11, the electrophotographic photoreceptors of Examples 1 to 11 are more stable than those of Comparative Examples 1 to 4 even when used repeatedly. It was confirmed that image quality defects due to ghost, fogging and black spots can be sufficiently suppressed. In addition, according to the electrophotographic photoreceptors of Examples 1 to 11, it was confirmed that black spots were sufficiently suppressed, and thus sufficient leakage preventing properties were obtained.

1 is a schematic cross-sectional view showing a preferred embodiment of an electrophotographic photoreceptor of the present invention. FIG. 5 is a schematic cross-sectional view showing another preferred embodiment of the electrophotographic photosensitive member of the present invention. FIG. 5 is a schematic cross-sectional view showing another preferred embodiment of the electrophotographic photosensitive member of the present invention. 1 is a schematic cross-sectional view showing a preferred embodiment of an image forming apparatus of the present invention. It is a schematic cross section which shows other suitable embodiment of the image forming apparatus of this invention. It is a schematic cross section which shows other suitable embodiment of the image forming apparatus of this invention. 1 is a schematic cross-sectional view showing a preferred embodiment of a process cartridge of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Conductive substrate, 2 ... Undercoat layer, 3 ... Photosensitive layer, 31 ... Charge generation layer, 32 ... Charge transport layer, 4 ... Intermediate layer, 5 ... Protective layer, 6 ... Single layer type photosensitive layer, 7 ... Electron Photoconductor, 8 ... charging means, 9 ... power supply, 10 ... exposure means, 11 ... developing means, 12 ... transfer means, 13 ... cleaning means, 14 ... staticizer, 15 ... fixing means, 16 ... mounting rail, 18 ... Opening for exposure, 20... Transferred body, 100, 110, 120 .. electrophotographic photosensitive member, 200, 210, 220... Image forming apparatus, 300.

Claims (7)

An electrophotographic photoreceptor comprising a conductive substrate, an undercoat layer formed on the conductive substrate, and a photosensitive layer formed on the undercoat layer,
The undercoat layer contains metal oxide particles, an electron accepting material, and an ionic material having the same basic skeleton as the electron accepting material,
The electrophotographic photosensitive member, wherein a content ratio of the ionic substance in the undercoat layer is 5 to 15% by mass based on a total amount of the electron accepting substance and the ionic substance.   2. The electron according to claim 1, wherein the electron-accepting substance has an anthraquinone structure having a hydroxyl group as a basic skeleton, and the ionic substance has an anthraquinone structure as a basic skeleton. Photoconductor.   The electrophotographic photoreceptor according to claim 1, wherein the ionic substance is a sulfonate having an anthraquinone structure as a basic skeleton.   The electrophotographic photosensitive member according to claim 1, wherein the metal oxide particles are surface-treated with a coupling agent.   5. The metal oxide particle according to claim 1, wherein the metal oxide particle is a particle made of at least one selected from the group consisting of titanium oxide, zinc oxide, tin oxide, and zirconium oxide. The electrophotographic photoreceptor described in 1. The electrophotographic photosensitive member according to any one of claims 1 to 5,
A charging means for charging the electrophotographic photosensitive member; a developing means for developing a latent electrostatic image formed on the electrophotographic photosensitive member with toner to form a toner image; and At least one selected from the group consisting of cleaning means for removing toner remaining on the surface;
A process cartridge comprising: The electrophotographic photosensitive member according to any one of claims 1 to 5,
Charging means for charging the electrophotographic photosensitive member;
Exposure means for forming an electrostatic latent image on the charged electrophotographic photosensitive member;
Developing means for developing the electrostatic latent image with toner to form a toner image;
Transfer means for transferring the toner image from the electrophotographic photosensitive member to a transfer target;
An image forming apparatus comprising:

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