JP2018028604A - Electrophotographic photoreceptor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor whose surface layer has a hardening resin formed by hardening a compound having a plurality of polymerizable functional groups, which can suppress image unevenness without impairing abrasion resistance.SOLUTION: An electrographic photoreceptor has a photosensitive layer on a support body. A surface layer of the electrographic photoreceptor has a hardening resin formed by hardening a compound having a plurality of polymerizable functional groups, and a calixarene compound having a specific structure. The content of the calixarene compound in the surface layer is in a range of 1-20 mass% with respect to all the component materials of the surface layer.SELECTED DRAWING: None

Description

  The present invention relates to an electrophotographic photoreceptor.

An electrophotographic photoreceptor is required to have abrasion resistance. Patent Document 1 and Patent Document 2 contain a cured product obtained by curing a charge transporting monomer having a polymerizable functional group in the surface layer of an electrophotographic photosensitive member to improve the abrasion resistance of the electrophotographic photosensitive member. Techniques to improve are described.
On the other hand, an electrophotographic photosensitive member provided with a surface layer containing a cured product has a small amount of wear, so that contaminants such as charged products and toner components are difficult to remove. These contaminants may cause charge injection or triboelectric charging during charging and development processes, disturbing the latent image. Further, when in-plane unevenness occurs in the concentration of contaminants on the surface of the electrophotographic photoreceptor, image unevenness has occurred.
As a technique for dealing with contaminants, Patent Document 3 discloses a method in which molecules that capture ions of charged products are included in the outermost surface layer of a photoreceptor.

JP 2000-66425 A JP 2010-156835 A JP 2010-79130 A

Since the contaminants include not only the charged product but also various substances such as a toner component, the molecule that captures ions of Patent Document 3 has an insufficient image unevenness suppressing effect.
An object of the present invention is to suppress image unevenness without impairing abrasion resistance in an electrophotographic photoreceptor having a surface layer containing a curable resin obtained by curing a compound having a plurality of polymerizable functional groups. The object is to provide an electrophotographic photoreceptor.

（式中、Ｙ_１〜Ｙ_６はそれぞれ独立に、−ＣＨ＝Ｎ−、−Ｎ＝ＣＨ−、−ＣＨ＝ＣＨ−または−Ｎ＝Ｎ−を示し、Ａｒ_１〜Ａｒ_６はそれぞれ独立に、置換基を有してもよい芳香族炭化水素環基または置換基を有してもよい複素環基を示す。） The present invention relates to an electrophotographic photosensitive member having a photosensitive layer on a support, wherein the surface layer of the electrophotographic photosensitive member is formed by curing a compound having a plurality of polymerizable functional groups, and the following formula ( A calixarene compound having a structure represented by any one of 1) to (3), wherein the content of the calixarene compound in the surface layer is 1% by mass or more of the total constituent material of the surface layer The electrophotographic photosensitive member is 20% by mass or less.

(In the formula, Y _{1 to} Y ₆ each independently represent —CH═N—, —N═CH—, —CH═CH— or —N═N—, and Ar _{1 to} Ar ₆ each independently represents An aromatic hydrocarbon ring group that may have a substituent or a heterocyclic group that may have a substituent.

  According to the present invention, in the electrophotographic photosensitive member having a surface layer containing a curable resin obtained by curing a compound having a plurality of polymerizable functional groups, image unevenness is suppressed without impairing wear resistance. An electrophotographic photoreceptor can be provided.

It is a figure which shows an example of the laminated constitution of the electrophotographic photoreceptor of this invention. 1 is a diagram illustrating an example of a schematic configuration of an electrophotographic apparatus including a process cartridge having the electrophotographic photosensitive member of the present invention.

（式中、Ｙ_１〜Ｙ_６はそれぞれ独立に、−ＣＨ＝Ｎ−、−Ｎ＝ＣＨ−、−ＣＨ＝ＣＨ−または−Ｎ＝Ｎ−を示し、Ａｒ_１〜Ａｒ_６はそれぞれ独立に、置換基を有してもよい芳香族炭化水素環基または置換基を有してもよい複素環基を示す。）
上述のとおり、本発明の電子写真感光体によって、耐摩耗性を損なうことなく画像ムラを抑制できる。 In the electrophotographic photoreceptor of the present invention, the surface layer of the electrophotographic photoreceptor is a curable resin obtained by curing a compound having a plurality of polymerizable functional groups, and any one of the following formulas (1) to (3): A calixarene compound having the structure shown, wherein the content of the calixarene compound in the surface layer is 1% by mass or more and 20% by mass or less of the total constituent material of the surface layer, To do.

(In the formula, Y _{1 to} Y ₆ each independently represent —CH═N—, —N═CH—, —CH═CH— or —N═N—, and Ar _{1 to} Ar ₆ each independently represents An aromatic hydrocarbon ring group that may have a substituent or a heterocyclic group that may have a substituent.
As described above, the electrophotographic photoreceptor of the present invention can suppress image unevenness without impairing the wear resistance.

The image unevenness to be improved in the present invention is caused by contaminants such as charged products and toner components on the electrophotographic photosensitive member (hereinafter also simply referred to as a photosensitive member) or oxides of the constituent components of the photosensitive member. When the present inventors examined using the conventional photoreceptor which contains curable resin in a surface layer, the following knowledge was acquired about generation | occurrence | production of the image nonuniformity.
(A) Image unevenness occurs when image output is repeated.
(B) The image unevenness is improved by removing the photoconductor in which the image unevenness has occurred from the electrophotographic apparatus, and wiping the surface or polishing the surface and then outputting the image again.
(C) Image unevenness occurs even in a low humidity environment.

  First, from (A) and (B), it is considered that the image unevenness to be improved by the present invention is caused by contaminants on the surface of the photoreceptor. Next, as image unevenness due to contaminants, there is known an image flow that occurs due to a decrease in resistance on the surface of the photoreceptor due to contaminants and water (high humidity). Image unevenness to be improved by the present invention is ( C) suggests that this is not the case.

  Therefore, the present inventors performed the following investigation assuming charge injection or frictional charging from a process due to contaminants. In an electrophotographic process that undergoes charging, exposure, development, transfer, and pre-exposure, a surface potential meter was installed in place of the transfer process, and it was examined whether or not the surface potential of the photoreceptor changed with and without the development process. At this time, when the toner is developed in the development process, the charge amount of the toner charge affects the surface potential of the photoreceptor. Therefore, in the development process, only the carrier is put into the developing device using the two-component developer, It was devised not to be done. As a result, the unused photoreceptor without image unevenness did not change the photoreceptor surface potential with or without the development process. However, on the photoconductor in which image unevenness occurred, a difference occurred in the surface potential of the photoconductor with and without the development process. More specifically, the surface potential at the transfer position after image exposure was −200 V when there was no development process, but −250 V when there was a development process. From this result, it was confirmed that the contaminant promotes charge injection from the development process or frictional charging in the development process.

  The above verification was a confirmation in the development process. However, if the contaminant causes charge injection or triboelectric charging, charge injection or triboelectric charging is performed in all processes that contact the photoconductor such as charging, transfer, and cleaning. May occur. However, it is difficult to control the resistance and charge acceptability of members used in all processes in order to improve image unevenness. Therefore, an attempt was made to improve the electrophotographic photoreceptor itself.

  The electrophotographic photoreceptor of the present invention contains a calixarene compound having a structure represented by any one of formulas (1) to (3) on the surface layer. Patent Document 3 discloses a photoconductor using t-butylcalix [5] arene as a molecule for capturing ions of discharge products. However, when this photoconductor is examined, the effect of improving image unevenness is not sufficient. There wasn't. Although the difference between the calixarene compound according to the present invention and the calixarene of Patent Document 3 is not clear, the present inventors believe that there is a difference in electron acceptability derived from the substituent. In other words, the electrophotographic photosensitive member of the present invention is in a state where charge injection or triboelectricity tends to occur on the entire surface due to calixarene having a high electron accepting property, and even if unevenness due to contaminants is added, the image is practically displayed. Assumes no impact.

  Although calixarene itself is known as a charge control agent for negatively charged toner, formulas (1) to (3) are considered to have particularly high charge acceptability due to their structure. Calixarene is known to form conformational isomers around a ring composed of phenol and methylene. In the compounds of formulas (1) to (3), the steric hindrance of the phenolic hydroxyl group is small, and the substituents Y and Ar are bulky, so the conformation isomer is predominantly the Cone type in which the phenolic hydroxyl group abuts the head. . Moreover, the substituent Y has electron withdrawing property. Therefore, the calixarene compounds of the formulas (1) to (3) are expected to have increased electron acceptability as a result of promoting both intramolecular polarization and intramolecular polarization.

In formulas (1) to (3), Y _{1 to} Y ₆ each independently represent —CH═N—, —N═CH—, —CH═CH—, or —N═N—, and Ar _{1 to} Ar Each ₆ independently represents an aromatic hydrocarbon ring group which may have a substituent or a heterocyclic group which may have a substituent. Ar _{1 to} Ar ₆ are preferably an aromatic hydrocarbon ring group or a heterocyclic group having at least one substituent selected from the group consisting of a cyano group, a nitro group and a halogen atom.

Examples of the aromatic hydrocarbon ring group or heterocyclic group for Ar _{1 to} Ar ₆ include groups derived from hydrocarbon aromatic rings such as benzene, naphthalene, fluorene, phenanthrene, anthracene, fluoranthene, and pyrene, furan, thiophene, pyridine, And groups derived from heterocyclic rings such as indole, benzothiazole, carbazole, benzocarbazole, acridone, dibenzothiophene, benzoxazole, benzotriazole, oxathiazole, thiazole, phenazine, cinnoline and benzocinnoline.
Ar _{1 to} Ar ₆ may have an alkyl group such as methyl, ethyl, propyl and butyl, an alkoxy group such as methoxy and ethoxy, a dialkylamino group such as dimethylamino and diethylamino, methoxycarbonyl and the like. Examples thereof include alkoxycarbonyl groups such as ethoxycarbonyl, halogen atoms such as fluorine atom, chlorine atom and bromine atom, hydroxy group, nitro group, cyano group and halomethyl group.
Ar _{1 to} Ar ₆ are preferably benzene ring groups having electron-withdrawing groups such as a cyano group, a nitro group, and a halogen atom. A phenyl group having a cyano group, a nitro group and a halogen atom at the meta position with respect to the binding site to Y _{1 to} Y ₆ is preferred. Ar _{1 to} Ar ₆ may have a plurality of substituents.

  The content of the calixarene compound having the structure represented by any one of formulas (1) to (3) in the surface layer is 1% by mass or more and 20% by mass or less of the total constituent materials of the surface layer. When the amount is less than 1% by mass, the effect of suppressing image unevenness is not sufficient, and when it exceeds 20% by mass, the wear resistance is inferior. The calixarene compound having a structure represented by any one of formulas (1) to (3) may be used alone, or two or more compounds of formulas (1) to (3) may be used in combination. When used in combination, the total weight of the calixarene compound in the surface layer is 1% by mass or more and 20% by mass or less of the total constituent materials of the surface layer.

  The surface layer can be formed as follows. First, a monomer that is a compound having a plurality of polymerizable functional groups and a calixarene compound having a structure represented by any one of formulas (1) to (3) are mixed to prepare a surface layer coating solution. Next, a coating film of this surface layer coating solution is formed, and the monomer in the coating film is cured to form a surface layer. At this time, a solvent may be added to the surface layer coating solution. The calixarene compound may be dissolved in the coating solution for the surface layer, or may be dispersed without being dissolved.

  The calixarene compound having a structure represented by any one of the formulas (1) to (3) can be produced by, for example, a synthesis method described in Japanese Patent No. 3295284. That is, the amine is tetrazotized by a conventional method and coupled with calixarene in the presence of alkali in an aqueous system, or after the tetrazonium salt is converted into a borofluoride salt or a zinc chloride double salt, tetrahydrofuran, N, N-dimethylformamide, It can be synthesized by coupling with calixarene in the presence of a base such as soda acetate, triethylamine, pyridine, N-methylmorpholine in an organic solvent such as dimethyl sulfoxide. A synthesis example of calixarene compound 1-9 described below is shown below. Here, “part” means “part by mass”.

  10 parts of 3,5-dinitroaniline was added to hydrochloric acid water consisting of 59 parts of concentrated hydrochloric acid and 170 parts of ion-exchanged water, and the dispersion was cooled to a temperature of −5 ° C. while stirring. A solution prepared by dissolving 4.15 parts of sodium nitrite in 9.07 parts of ion-exchanged water was dropped into the dispersion. After stirring for 60 minutes, 1 part of activated carbon was added, stirred for 1 minute and filtered. While stirring the filtrate, the solution was cooled to -5 ° C., and a solution obtained by dissolving 10.8 parts of sodium borofluoride in 32.4 parts of ion-exchanged water was added dropwise. The mixture was stirred for 60 minutes and then filtered. The filtrate was collected, dispersed and washed for 60 minutes in a solution obtained by dissolving 7.5 parts of sodium borofluoride in 150 parts of ion-exchanged water, and filtered. The filtrate was collected, dispersed and washed for 30 minutes in a mixed solution of 7.8 parts of acetonitrile and 43.2 parts of isopropyl ether, and filtered. The filtrate was recovered to obtain 10.6 parts of borofluoride (yield 68.6%).

  Next, under a nitrogen atmosphere, 1.8 parts of calix [4] arene was dissolved in 211.2 parts of tetrahydrofuran, and then cooled to a temperature of −5 ° C. 6 parts of the borofluoride synthesized above was added to the solution and stirred for 30 minutes. Further, 5.88 parts of pyridine were slowly added dropwise while maintaining the liquid temperature of -5 ° C. The residue was collected, dispersed and washed in 130 parts of 2.5% aqueous hydrochloric acid for 60 minutes, and then filtered. The filtrate was collected, dispersed and washed with 300 parts of ion exchange water for 60 minutes, and then filtered. The dispersion washing of ion exchange water was repeated again. The residue was collected, dispersed and washed in 413 parts of acetone for 60 minutes, and then filtered. After the filtrate was collected and vacuum dried, 3.89 parts of orange crystalline calixarene compound 1-9 was obtained (yield 76.0%).

The electrophotographic photosensitive member of the present invention includes a support, a charge generation layer formed on the support, a charge transport layer formed on the charge generation layer, and a protection formed on the charge transport layer as necessary. Has a layer.
FIG. 1 is a diagram illustrating an example of a layer structure of an electrophotographic photosensitive member. In FIG. 1, the electrophotographic photosensitive member includes a support 101, a charge generation layer 102, a charge transport layer 103, and a protective layer 104. When the protective layer 104 is not provided, the charge transport layer 103 is a surface layer. The surface layer contains a curable resin obtained by curing a compound having a plurality of polymerizable functional groups, and a calixarene compound having a structure represented by any of the following formulas (1) to (3). If necessary, a conductive layer or undercoat layer described later may be provided between the support and the photosensitive layer (charge generation layer, charge transport layer).

As the support used in the electrophotographic photosensitive member, a conductive one (conductive support) is preferable. For example, a support made of a metal such as aluminum, an aluminum alloy, or stainless steel or an alloy can be used. In the case of a support made of aluminum or aluminum alloy, an ED (Extrusion Drawing) tube, an EI (Extrusion Ironing) tube, or a support obtained by cutting, electrolytic composite polishing, wet or dry honing treatment of these can also be used. Alternatively, a thin film of a conductive material such as aluminum, an aluminum alloy, or an indium oxide-tin oxide alloy may be formed on a metal support or resin support, and used as a support.
The surface of the support may be subjected to cutting treatment, roughening treatment, alumite treatment, or the like.
A support formed by impregnating a resin or the like with conductive particles such as carbon black, tin oxide particles, titanium oxide particles, or silver particles, or a support made of conductive resin can also be used.

A conductive layer containing conductive particles and a binder resin may be provided between the support and the charge generation layer or the undercoat layer described below.
The conductive layer is formed by coating a conductive layer coating solution obtained by dispersing conductive particles together with a binder resin and a solvent to form a coating film, and then drying and / or curing the obtained coating film. can do.

Examples of conductive particles used in the conductive layer include carbon black such as acetylene black, metal particles such as aluminum, nickel, iron, nichrome, copper, zinc, and silver, tin oxide, and ITO (Indium Tin Oxide). And metal oxide particles.
Examples of the resin used for the conductive layer include acrylic resin, alkyd resin, epoxy resin, phenol resin, butyral resin, polyacetal, polyurethane, polyester, polycarbonate, and melamine resin.
Examples of the solvent used in the conductive layer coating solution include ether solvents, alcohol solvents, ketone solvents, and aromatic hydrocarbon solvents.
The thickness of the conductive layer is preferably 0.2 μm or more and 40 μm or less, and more preferably 5 μm or more and 40 μm or less.

An undercoat layer may be provided between the support or the conductive layer and the charge generation layer.
The undercoat layer can be formed by applying a coating solution for an undercoat layer containing a resin to form a coating film, and drying or curing the obtained coating film.

Examples of the resin used for the undercoat layer include polyacrylic acid, methylcellulose, ethylcellulose, polyamide, polyimide, polyamideimide, polyamic acid, melamine resin, epoxy resin, and polyurethane.
The undercoat layer may contain the above-described conductive particles, semiconductive particles, electron transporting material, and electron accepting material.
Examples of the solvent used in the coating solution for the undercoat layer include ether solvents, alcohol solvents, ketone solvents, aromatic hydrocarbon solvents, and the like.
The thickness of the undercoat layer is preferably 0.05 μm or more and 40 μm or less, and more preferably 0.4 μm or more and 20 μm or less.

A charge generation layer is formed on the support, the conductive layer, or the undercoat layer.
Examples of the charge generating material used in the electrophotographic photosensitive member include pyrylium, thiapyrylium dyes, phthalocyanine compounds, anthanthrone pigments, dibenzpyrenequinone pigments, pyranthrone pigments, azo pigments, indigo pigments, quinacridone pigments, and quinocyanine pigments. It is done. Among these, gallium phthalocyanine is preferable. Furthermore, from the viewpoint of high sensitivity, hydroxygallium phthalocyanine is preferable, and among them, strong peaks at the Bragg angle 2θ of 7.4 ° ± 0.3 ° and 28.2 ° ± 0.3 ° in CuKα characteristic X-ray diffraction Hydroxygallium phthalocyanine crystals having the following are preferred.

  Examples of the binder resin used for the charge generation layer include polycarbonate, polyester, butyral resin, polyvinyl acetal, acrylic resin, vinyl acetate resin, and urea resin. Among these, a butyral resin is preferable. These resin may use only 1 type and may use 2 or more types together as a mixture or a copolymer.

The charge generation layer is formed by applying a charge generation layer coating solution obtained by dispersing a charge generation material together with a binder resin and a solvent to form a coating film, and then drying the obtained coating film. Can do. The charge generation layer may be a vapor generation film of a charge generation material.
In the charge generation layer, the ratio of the charge generation material to the binder resin is preferably 0.3 parts by mass or more and 4 parts by mass or less for the binder resin with respect to 1 part by mass of the charge generation material.
Examples of the dispersion treatment method include a method using a homogenizer, an ultrasonic wave, a ball mill, a sand mill, an attritor, and a roll mill.
Examples of the solvent used in the charge generation layer coating solution include alcohol solvents, sulfoxide solvents, ketone solvents, ether solvents, ester solvents, and aromatic hydrocarbon solvents.
The thickness of the charge generation layer is preferably from 0.01 μm to 5 μm, and more preferably from 0.1 μm to 1 μm.
In addition, various sensitizers, antioxidants, ultraviolet absorbers, and plasticizers can be added to the charge generation layer as necessary.

The charge transport layer is formed by applying a charge transport layer coating solution obtained by dissolving a charge transport material and a binder resin in a solvent to form a coating film, and then drying the obtained coating film. Can do.
Examples of the charge transport material used in the charge transport layer include triarylamine compounds, hydrazone compounds, stilbene compounds, pyrazoline compounds, oxazole compounds, thiazole compounds, and triarylmethane compounds.
Examples of the binder resin used for the charge transport layer include polyvinyl butyral, polyarylate, polycarbonate, polyester, phenoxy resin, polyvinyl acetate, acrylic resin, polyacrylamide, polyamide, polyvinyl pyridine, cellulose resin, urethane resin, and epoxy resin. , Agarose resin, cellulose resin, casein, polyvinyl alcohol, and polyvinylpyrrolidone. These resin may use only 1 type and may use 2 or more types together as a mixture or a copolymer.
The ratio of the charge transport material is preferably 30% by mass to 70% by mass with respect to the total mass of the charge transport layer.
Examples of the solvent used in the charge transport layer coating solution include ether solvents, alcohol solvents, ketone solvents, and aromatic hydrocarbon solvents. The thickness of the charge transport layer is preferably 5 μm or more and 40 μm or less.

  The surface layer of the electrophotographic photoreceptor may be a charge transport layer, a protective layer on the charge transport layer, or a second charge transport layer having charge transport capability. . Regardless of the layer configuration, the surface layer is a curable resin obtained by curing a compound having a plurality of polymerizable functional groups, and a calixarene having a structure represented by any one of formulas (1) to (3). Compound. Below, description as a surface layer is performed.

  The surface layer contains a calixarene compound having a structure represented by any one of the formulas (1) to (3) in an amount of 1% by mass to 20% by mass with respect to all constituent materials of the surface layer.

The content of the calixarene compound contained in the surface layer can be confirmed after the surface layer is formed. For example, it is the following method.
First, the layer on the support including the surface layer is peeled off from the support using a blade. Next, layers other than the surface layer are dissolved using methyl ethyl ketone or the like, and only the surface layer composed of a cured product that does not dissolve in the solvent is taken out. After measuring the weight of the surface layer, the calixarene compound is dissolved by immersing it in a solvent that dissolves the calixarene compound such as N, N-dimethylformamide and heating under reduced pressure if necessary. This eluate is measured by NMR or liquid chromatography, and the concentration is determined in light of a calibration curve of a N, N-dimethylformamide solution of calixarene compound, separately measured. The content is calculated using the surface layer weight obtained previously.

Examples of the calixarene compound having the structure represented by the formula (1) include the following compounds.

Examples of the calixarene compound having the structure represented by the formula (2) include the following compounds.

Examples of the calixarene compound having the structure represented by the formula (3) include the following compounds.

  The compound having a plurality of polymerizable functional groups used in the surface layer may be a polymerizable monomer, or a dimer or oligomer in which a plurality of them are connected. Examples of the compound having a polymerizable functional group include a compound having a chain polymerizable functional group such as an acryloyloxy group and a styryl group, and a sequentially polymerizable functional group such as a hydroxyl group, an alkoxysilyl group, an isocyanate group, and an epoxy group. Compounds. From the viewpoint of wear resistance and electrophotographic characteristics, a compound having two or more polymerizable functional groups in the same molecule is more preferable.

  Furthermore, it is more preferable to use a compound having both a charge transporting structure (preferably a hole transporting structure) and a polymerizable functional group in the same molecule. From the viewpoint of maintaining electrophotographic characteristics, the polymerizable functional group is preferably an acryloyloxy group.

Examples of the compound having a plurality of polymerizable functional groups include the following compounds.

  The surface layer coating solution is prepared by mixing a monomer, which is a compound having a plurality of polymerizable functional groups, and a calixarene compound having a structure represented by any one of formulas (1) to (3). At this time, the calixarene compound may be dissolved in the coating solution, or may be dispersed without being dissolved.

  Various additives can be added to the surface layer. Examples of the additive include deterioration preventing agents such as antioxidants and ultraviolet absorbers, and lubricants such as polytetrafluoroethylene (PTFE) particles and carbon fluoride. Further, polymerization control agents such as polymerization reaction initiators and polymerization reaction terminators, leveling agents such as silicone oil, surfactants, and the like are also included.

Solvents used in the surface layer coating solution include alcohol solvents such as methanol, ethanol and propanol, ketone solvents such as acetone, methyl ethyl ketone and cyclohexanone, ester solvents such as ethyl acetate and butyl acetate, tetrahydrofuran, dioxane and the like. Ether solvents, 1,1,2,2,3,3,4-heptafluorocyclopentane, halogen solvents such as dichloromethane, dichloroethane, chlorobenzene, aromatic solvents such as benzene, toluene, xylene, methyl cellosolve, ethyl Examples include cellosolve solvents such as cellosolve. These solvents may be used alone or in combination of two or more.
The film thickness of the surface layer is preferably 2 μm or more and 20 μm or less.

  When applying the coating solution for each layer, for example, a coating method such as a dip coating method (dipping method), a spray coating method, a spinner coating method, a bead coating method, a blade coating method, or a beam coating method can be used.

  Examples of the reaction for curing the compound having a plurality of polymerizable functional groups include radical polymerization, ion polymerization, thermal polymerization, photopolymerization, radiation polymerization (electron beam polymerization), plasma CVD method, and photo CVD method. Curing can be performed using heat, light (such as ultraviolet rays), or radiation (such as electron beams). Among these, polymerization using radiation is preferable, and polymerization using an electron beam is more preferable among radiations. Curing with an electron beam is highly productive because it is a short and efficient polymerization reaction. When irradiating an electron beam, examples of the accelerator include a scanning type, an electro curtain type, a broad beam type, a pulse type, and a laminar type.

  When an electron beam is used, the acceleration voltage of the electron beam is preferably 120 kV or less from the viewpoint of suppressing material property deterioration due to the electron beam without impairing the polymerization efficiency. Moreover, the electron beam absorbed dose on the surface of the coating film of the surface layer coating solution is preferably 1 kGy or more and 50 kGy or less, and more preferably 5 kGy or more and 10 kGy or less.

  In addition, when the above compound is cured (polymerized) using an electron beam, it is preferable to irradiate the electron beam in an inert gas atmosphere and then heat in the inert gas atmosphere for the purpose of suppressing the polymerization inhibiting action due to oxygen. . Examples of the inert gas include nitrogen, argon, and helium.

FIG. 2 shows an example of a schematic configuration of an electrophotographic apparatus provided with a process cartridge having an electrophotographic photosensitive member.
In FIG. 2, a cylindrical electrophotographic photosensitive member 1 is driven to rotate at a predetermined peripheral speed (process speed) in the direction of an arrow about an axis 2. The surface (circumferential surface) of the electrophotographic photosensitive member 1 is positively or negatively charged by a charging unit (primary charging unit) 3 during the rotation process. Next, the surface of the electrophotographic photoreceptor 1 is irradiated with exposure light (image exposure light) 4 output from an exposure means (image exposure means) (not shown). The exposure light 4 is intensity-modulated corresponding to the time-series electric digital image signal of the target image information. Examples of exposure means include slit exposure and laser beam scanning exposure. Thus, an electrostatic latent image corresponding to the target image information is formed on the surface of the electrophotographic photoreceptor 1.

  The electrostatic latent image formed on the surface of the electrophotographic photoreceptor 1 is then developed (regular development or reversal development) with toner stored in the developing means 5 to form a toner image. The toner image formed on the surface of the electrophotographic photoreceptor 1 is transferred to the transfer material 7 by the transfer means 6. Here, when the transfer material 7 is paper, it is taken out from a paper feeding unit (not shown) in synchronization with the rotation of the electrophotographic photosensitive member 1 and fed between the electrophotographic photosensitive member 1 and the transfer means 6. Is done. Further, a bias voltage having a polarity opposite to the charge held in the toner is applied to the transfer means 6 from a bias power source (not shown). The transfer means may be an intermediate transfer type transfer means having a primary transfer member, an intermediate transfer member, and a secondary transfer member.

  The transfer material 7 onto which the toner image has been transferred is separated from the surface of the electrophotographic photosensitive member 1, transported to a fixing unit 8, and subjected to a fixing process of the toner image, whereby an electronic image forming product (print, copy) is obtained. Printed out of the photographic device.

  The surface of the electrophotographic photoreceptor 1 after the transfer of the toner image is cleaned by a cleaning unit 9 to remove deposits such as transfer residual toner. The transfer residual toner can also be collected by a developing means or the like. Further, if necessary, the surface of the electrophotographic photosensitive member 1 is subjected to charge removal treatment by irradiation with pre-exposure light 10 from a pre-exposure unit (not shown), and then repeatedly used for image formation. When the charging unit 3 is a contact charging unit using a charging roller or the like, the pre-exposure unit is not always necessary.

  Among the components selected from the electrophotographic photosensitive member 1, the charging unit 3, the developing unit 5, the transfer unit 6, and the cleaning unit 9, a plurality of components may be housed in a container to form a process cartridge. Further, the process cartridge may be detachable from the main body of the electrophotographic apparatus. For example, the electrophotographic photoreceptor 1 and at least one means selected from the group consisting of charging means 3, developing means 5, transfer means 6 and cleaning means 9 are integrally supported to form a cartridge. Then, the process cartridge 11 can be detachably attached to the main body of the electrophotographic apparatus using guide means 12 such as a rail of the main body of the electrophotographic apparatus.

Hereinafter, specific examples will be given and described in more detail. In the examples, “part” means “part by mass”. In addition, the electrophotographic photoreceptor is hereinafter simply referred to as “photoreceptor”.
(Production Example 1 of electrophotographic photosensitive member)
-Support As a support, a cylindrical aluminum cylinder having a diameter of 29.92 mm, a length of 357.5 mm, and a thickness of 0.7 mm was used.
-Undercoat layer Next, 100 parts of zinc oxide particles (specific surface area: 19 m ² / g, powder resistance: 4.7 × 10 ⁶ Ω · cm) as a metal oxide were stirred and mixed with 500 parts of toluene. To this, 0.8 part of a silane coupling agent (compound name: N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, trade name: KBM602, manufactured by Shin-Etsu Chemical Co., Ltd.) is added for 6 hours. Stir. Thereafter, toluene was distilled off under reduced pressure, followed by heating and drying at 140 ° C. for 6 hours to obtain surface-treated zinc oxide particles.
Next, 15 parts of butyral resin (trade name: BM-1, manufactured by Sekisui Chemical Co., Ltd.) and blocked isocyanate (trade name: Sumidur 3175, Sumika Covestro Urethane Co., Ltd. (former: Sumitomo Bayer Urethane) as polyol resin 15 parts) was dissolved in the mixed solution. The mixed solution is a mixture of 73.5 parts of methyl ethyl ketone and 73.5 parts of 1-butanol.

To this solution, 80.8 parts of the surface-treated zinc oxide particles and 0.4 part of 2,3,4-trihydroxybenzophenone (manufactured by Tokyo Chemical Industry Co., Ltd.) were added, and this was added to a glass having a diameter of 0.8 mm. Dispersion was performed in a sand mill apparatus using beads in an atmosphere of 23 ± 3 ° C. for 3 hours. After dispersion, 0.01 parts of silicone oil (trade name: SH28PA, manufactured by Toray Dow Corning Silicone) (formerly Toray Dow Corning Silicone), crosslinked polymethyl methacrylate (PMMA) particles (trade name: TECHPOLYMER SSX-103, 5.6 parts by Sekisui Plastics Co., Ltd., average primary particle size 3.1 μm) was added and stirred to prepare a coating solution for the undercoat layer.
This undercoat layer coating solution was applied onto the support by dip coating, and the resulting coating film was dried at 160 ° C. for 40 minutes to form an undercoat layer having a thickness of 18 μm.

-Charge generation layer Next, the following four substances were placed in a sand mill using glass beads having a diameter of 1 mm, dispersed for 4 hours, and then 700 parts of ethyl acetate was added to prepare a charge generation layer coating solution. .
・ Hydroxygallium phthalocyanine crystal in a crystal form having strong peaks at 7.4 ° and 28.2 ° with Bragg angle 2θ ± 0.2 ° in CuKα characteristic X-ray diffraction (charge generation material)
・ ・ ・ 20 parts ・ Polyvinyl butyral (trade name: ESREC BX-1, manufactured by Sekisui Chemical Co., Ltd.)
10 parts ・ Cyclohexanone 600 parts This coating solution for charge generation layer is dip-coated on the undercoat layer, and the resulting coating film is dried at 80 ° C. for 15 minutes to obtain a film thickness of 0.18 μm. The charge generation layer was formed.

この電荷輸送層用塗布液を電荷発生層上に浸漬塗布し、得られた塗膜を３０分間１１０℃で乾燥させることによって、膜厚１８μｍの電荷輸送層を形成した。 -Charge transport layer Next, the following five substances were dissolved in a mixed solvent of 600 parts of xylene and 200 parts of dimethoxymethane to prepare a charge transport layer coating solution.
・ Compound represented by the following structural formula (t) (charge transporting substance) 30 parts ・ Compound represented by the following structural formula (u) (charge transporting substance) 60 parts ・ In the following structural formula (v) Compound shown (charge transporting substance) 10 parts Polycarbonate resin (trade name: Iupilon Z400, Mitsubishi Engineering Plastics, bisphenol Z type polycarbonate) 100 parts Structural formula (w) (Viscosity average molecular weight Mv: 20000)
... 0.02 parts

The charge transport layer coating solution was dip coated on the charge generation layer, and the resulting coating film was dried at 110 ° C. for 30 minutes to form a charge transport layer having a thickness of 18 μm.

Protective layer 1,1,2,2,3,3,4-heptafluorocyclopentane (trade name: Zeolora H, manufactured by Nippon Zeon Co., Ltd.) 100 parts / 1-propanol 100 parts mixed solvent, polyfluorone The mixture was filtered with a filter (trade name: PF-040, manufactured by Advantech Toyo Co., Ltd.). As described below, a monomer, which is a compound having a plurality of polymerizable functional groups, and a calixarene compound were added to the mixed solvent as described below. By filtering this with a polyflon filter (trade name: PF-020, manufactured by Advantech Toyo Co., Ltd.), a coating solution for a protective layer was prepared.
-Exemplified compound 1-9 ... 5 parts-Exemplified compound 4-3 ... 95 parts This coating solution for protective layer is dip-coated on the charge transport layer, and the obtained coating film is 50 minutes in the air for 6 minutes. Dry at 0C. Thereafter, in nitrogen, the coating film was irradiated with an electron beam for 1.6 seconds under the conditions of an acceleration voltage of 70 kV and an absorbed dose of 8000 Gy while rotating the support (object to be irradiated) at 200 rpm.
Subsequently, the temperature was raised from 25 ° C. to 120 ° C. over 30 seconds in nitrogen, and the coating film was heated. The oxygen concentration in the atmosphere during electron beam irradiation and subsequent heating was 15 ppm. Next, a protective layer having a thickness of 5 μm was formed by performing heat treatment at 100 ° C. for 30 minutes in the air.
An electrophotographic photoreceptor was produced as described above.

(Production example 2 of electrophotographic photosensitive member)
An electrophotographic photosensitive member was produced in the same manner as in Production Example 1 of the electrophotographic photosensitive member, except that the coating solution for the protective layer was changed as follows.

-Coating liquid for protective layer First, the lubricant dispersion liquid was produced in the following procedure.
1.5 parts of a fluorine atom-containing resin (trade name: GF-300, manufactured by Toagosei Co., Ltd.) as a dispersant was dissolved in the following mixed solvent.
・ 1,1,2,2,3,3,4-heptafluorocyclopentane (trade name: Zeorora H, manufactured by Nippon Zeon Co., Ltd.) ・ ・ ・ 30 parts ・ 1-propanol ・ ・ ・ 30 parts 30 parts of polytetrafluoroethylene particles (trade name: Lubron L-2, manufactured by Daikin Industries, Ltd.) as a lubricant were added. This was put into a high-pressure disperser (trade name: Microfluidizer M-110EH, manufactured by Microfluidics, USA), and subjected to dispersion treatment four times at a pressure of 600 kgf / cm ² . This was filtered with a polyflon filter (trade name: PF-040, manufactured by Advantech Toyo Co., Ltd.) to obtain a lubricant dispersion.

Next, a mixed solvent of 70 parts of 1,1,2,2,3,3,4-heptafluorocyclopentane (trade name: Zeolora H, manufactured by Nippon Zeon Co., Ltd.) / 1 70 parts of 1-propanol was added to polyflon. The mixture was filtered with a filter (trade name: PF-040, manufactured by Advantech Toyo Co., Ltd.). The compound was added to this mixed solvent so that it might become a total of 70 parts as follows. The monomer solution was obtained by filtering this with a polyfluorone filter (trade name: PF-020, manufactured by Advantech Toyo Co., Ltd.).
-Exemplified compound 1-9 ... 5 parts-Exemplified compound 4-3 ... 65 parts The obtained lubricant dispersion was mixed with a monomer solution to prepare a coating solution for a protective layer.

(Production Example 3 of electrophotographic photosensitive member)
An electrophotographic photosensitive member was produced in the same manner as in Production Example 1 of the electrophotographic photosensitive member, except that the protective layer was changed as follows.
-Protective layer After dissolving 1 part of 1-hydroxy-cyclohexyl-phenyl-ketone (trade name: Irgacure 184, BASF (former: Ciba Specialty Chemicals)) in 100 parts of n-propanol, The compounds were added to a total of 100 parts.
-Exemplified compound 1-9 ... 5 parts-Exemplified compound 4-3 ... 95 parts Furthermore, 1,1,2,2,3,3,4-heptafluorocyclopentane 100 parts, 4-methoxyphenol 0. A coating solution for protective layer was prepared by adding 01 parts.
This coating solution for protective layer was dip coated on the charge transport layer to form a coating film, and the resulting coating film was heat-treated at 50 ° C. for 5 minutes. Thereafter, using a metal halide lamp, the coating film was irradiated with ultraviolet rays for 20 seconds under the condition of irradiation intensity: 500 mW / cm ² , and heat-treated for 30 minutes under the condition that the coating film reached 130 ° C., thereby protecting the film thickness of 5 μm. A layer was formed.

(Production Example 4 of electrophotographic photoreceptor)
An electrophotographic photosensitive member was produced in the same manner as in Production Example 1 of the electrophotographic photosensitive member, except that the coating solution for the protective layer was changed to the following.
-Coating solution for protective layer 1,1,2,2,3,3,4-heptafluorocyclopentane (trade name: Zeolora H, manufactured by Nippon Zeon Co., Ltd.) 100 parts / 1-propanol 100 parts mixed solvent The solution was filtered through a polyflon filter (trade name: PF-040, manufactured by Advantech Toyo Co., Ltd.). The compound was added to this mixed solvent so that it might become a total of 100 parts as follows. By filtering this with a polyflon filter (trade name: PF-020, manufactured by Advantech Toyo Co., Ltd.), a coating solution for a protective layer was prepared.
Exemplified compound 1-9 ... 5 parts Exemplified compound 4-26 ... 45 parts Exemplified compound 4-25 ... 50 parts

(Evaluation of wear resistance)
Using an iR-ADV C5255 electrophotographic photosensitive member manufactured by Canon Inc. and a jig, the amount of wear due to rubbing of the cleaning blade was examined. As the jig, a jig having a motor for supporting the cartridge and rotating the electrophotographic photosensitive member was used. The electrophotographic photosensitive member produced in the cartridge is mounted in a normal temperature and low humidity environment at a temperature of 23 ° C. and a humidity of 5% RH, the AC voltage applied to the charging roller is set to Vpp 2000 V, and the rotational speed of the electrophotographic photosensitive member is 250 mm. / Sec, and the test was conducted for 6 hours. The film thickness before and after the test was measured with an eddy current film thickness meter (Fischerscope, manufactured by Helmut Fischer). Six points were measured uniformly in the generatrix direction of the cylindrical electrophotographic photosensitive member, and the average value of the six points was adopted as the total thickness of the organic layer. The difference in total film thickness before and after the test was determined as the amount of scraping (μm).

(Evaluation of image unevenness)
The electrophotographic photosensitive member was evaluated for image unevenness. An electrophotographic photosensitive member was mounted on a black station of Canon Inc. iR-ADV C5255, and 8000 A3-size halftones were continuously output in a room temperature and low humidity environment of 23 ° C. and 5% RH. At this time, the AC voltage applied to the charging roller was set to Vpp2000V. The density difference of image unevenness was measured for the output image after 8000 sheets. The measurement was performed with an X-rite 518JP / LP aperture 3.4 mm spectral densitometer manufactured by X-Rite Co., Ltd., and when the density difference exceeded 0.02, there was image unevenness, and 0.02 or less was determined as no image unevenness.

(Examples 1 to 21)
In each Example, one of the methods of Production Examples 1 to 4 of the electrophotographic photosensitive member was selected to produce an electrophotographic photosensitive member. At this time, the compounds used in the coating solution for the second charge transport layer (protective layer) were changed to the exemplified compounds and the number of parts as shown in Table 1. Two electrophotographic photoreceptors were prepared for each example, one for the above-mentioned wear resistance test and the other for the above-mentioned image unevenness evaluation. The results are shown in Table 1.

(Comparative Examples 1-8)
In each comparative example, one was selected from the methods of Production Examples 1 to 4 of the electrophotographic photosensitive member to prepare an electrophotographic photosensitive member. At this time, the compounds used in the coating solution for the second charge transport layer (protective layer) were changed to the exemplified compounds and the number of parts as shown in Table 1. Two electrophotographic photoreceptors were prepared for each example, one for the above-mentioned wear resistance test and the other for the above-mentioned image unevenness evaluation. The results are shown in Table 2. However, the calixarene compounds used in Comparative Examples 5 and 6 are the following compounds 5-1 and 5-2.

(Comparative Example 9)
An electrophotographic photosensitive member was produced in the same manner as in Production Example 1 of the electrophotographic photosensitive member, except that the coating solution for the protective layer was changed as follows. When this photoreceptor was evaluated for abrasion resistance and image unevenness, the scraping amount was less than 0.1 μm (below the measurement limit), but the image unevenness had a density difference of 0.07.
-Coating solution for protective layer 1,1,2,2,3,3,4-heptafluorocyclopentane (trade name: Zeolora H, manufactured by Nippon Zeon Co., Ltd.) 100 parts / 1-propanol 100 parts mixed solvent The solution was filtered through a polyflon filter (trade name: PF-040, manufactured by Advantech Toyo Co., Ltd.). In this mixed solvent, 96.8 parts of Exemplified Compound 4-3, a crystalline form of hydroxygallium having strong peaks at 7.4 ° and 28.2 ° of Bragg angle 2θ ± 0.2 ° in CuKα characteristic X-ray diffraction 2 parts of phthalocyanine crystal (charge generation material), 1 part of polyvinyl butyral (trade name: ESREC BX-1, manufactured by Sekisui Chemical Co., Ltd.) and 0.2 part of exemplified compound 1-9 were added and mixed with stirring. By filtering this with a polyflon filter (trade name: PF-020, manufactured by Advantech Toyo Co., Ltd.), a coating solution for a protective layer was prepared.

According to the examples, the electrophotographic photosensitive member according to the present invention has a shaving amount of 0.2 μm or less and an image unevenness with a density difference of 0.02 or less with a spectral densitometer, so that the image unevenness is not impaired. It can be said that the electrophotographic photosensitive member is suppressed in the above.
In Comparative Examples 1 to 3 and Comparative Example 7, when the added amount of the calixarene compound was less than 1% by mass, the effect of improving image unevenness was not sufficiently obtained.
In Comparative Example 4 and Comparative Example 8, when the added amount of the calixarene compound exceeded 20% by mass, the amount of scraping increased and the wear resistance was impaired.
In Comparative Examples 5 and 6, when _Y 1 to Y ₆ in the formula (1) and (2) is a tertiary butyl group, image unevenness improvement was not obtained sufficiently. It is speculated that the electron acceptability of the calixarene compound was insufficient.

DESCRIPTION OF SYMBOLS 101 Support body 102 Charge generation layer 103 Charge transport layer 104 Protective layer 1 Electrophotographic photosensitive member 2 Axis 3 Charging means 4 Exposure light 5 Developing means 6 Transfer means 7 Transfer material 8 Fixing means 9 Cleaning means 10 Pre-exposure light 11 Process cartridge 12 Guide means

Claims (2)

In an electrophotographic photoreceptor having a photosensitive layer on a support,
The surface layer of the electrophotographic photoreceptor is
A curable resin obtained by curing a compound having a plurality of polymerizable functional groups;
A calixarene compound having a structure represented by any of the following formulas (1) to (3),
An electrophotographic photoreceptor, wherein the content of the calixarene compound in the surface layer is 1% by mass or more and 20% by mass or less of the total constituent material of the surface layer.

(In the formula, Y _{1 to} Y ₆ each independently represent —CH═N—, —N═CH—, —CH═CH— or —N═N—, and Ar _{1 to} Ar ₆ each independently represents An aromatic hydrocarbon ring group that may have a substituent or a heterocyclic group that may have a substituent. The Ar _{1 to} Ar ₆ are an aromatic hydrocarbon ring group or a heterocyclic group having at least one substituent selected from the group consisting of a cyano group, a nitro group, and a halogen atom. Electrophotographic photoreceptor.

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