JP2016218212A - Electrophotographic photoreceptor, electrophotographic photoreceptor cartridge, and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor that maintains electrical characteristics and wear resistance of a photoreceptor and has excellent adhesiveness between a support and a photosensitive layer, an electrophotographic photoreceptor cartridge, and an image forming apparatus.SOLUTION: In a lamination type electrophotographic photoreceptor including at least a charge generating layer and a charge transport layer in this order on a conductive substrate, the charge generating layer contains spherical silica particles including primary particles manufactured with a specific manufacturing method and having a volume average particle diameter of 200 nm or less.SELECTED DRAWING: None

Description

The present invention relates to an electrophotographic photosensitive member used for an electrophotographic printer, a copying machine, a multifunction machine, and the like, a cartridge made using the electrophotographic photosensitive member, and an image forming apparatus.
More specifically, in a photosensitive layer having a charge generation layer and a charge transport layer in this order on a conductive substrate, an electrophotographic photoreceptor containing specific silica particles in the charge generation layer, and a cartridge using the electrophotographic photoreceptor And an image forming apparatus.

For the electrophotographic photoreceptor (hereinafter also referred to as “photoreceptor” where appropriate) that is the core of electrophotographic technology, an organic photoconductive material is used that has the advantage of being non-polluting and easy to form and manufacture. The photoreceptors used are widely used.
Electrophotographic image forming apparatuses are required to have higher image quality, higher speed, and higher durability year by year. Processes around the photoreceptor such as charging, exposure, development, and transfer have been improved to meet these requirements, but there are still many cases where improvement of the photoreceptor itself is still necessary. One example is improved wear resistance.

  In particular, studies and improvements on binder resins for overcoat layers and charge transport layers have been actively conducted in order to reduce film scraping in laminated photosensitive layers (Patent Document 1). However, when a resin having excellent mechanical strength is used, the internal stress of the film is increased, and there is a drawback that the adhesiveness of the photosensitive layer is deteriorated. Also, in a contact charging machine, the photosensitive layer may be lifted by rubbing the end of the charging roller, or in a machine using toner having a high average circularity, the cleaning blade contacts the photoconductor with a higher pressure. As a result, film peeling and lifting may occur at the end. As a method for solving these peeling problems, studies on the undercoating and the binder resin for the charge generation layer, improvement of the binder resin itself for the charge transport layer, and the like have been performed.

  The inventors of the present invention have intensively studied a method for improving only the adhesiveness while maintaining the wear strength and electrical characteristics of the photoreceptor, and as a result, it has been found that it is effective to add fine particles to the charge generation layer. The addition of particles to the charge generation layer has been studied so far (Patent Documents 2 to 4), but all have been aimed at preventing interference fringes of images and suppressing electrical deterioration. Patent Document 5 describes a method for producing surface-treated silica fine particles, but does not describe inclusion of this in a photosensitive layer of an electrophotographic photosensitive member.

Japanese Patent Application Laid-Open No. 2014-191079 JP-A-6-59462 JP 2011-227234 A JP 2002-49165 A JP 2015-13788 A

In the present invention, by adding fine particles to the charge generation layer, in addition to the anchor effect by the particles, the interaction of each resin and composition in the undercoat layer / charge generation layer / charge transport layer is changed. The purpose is to improve adhesiveness. In particular, it is presumed that the adhesion is improved when the binder resin or the charge transport material in the charge transport layer easily enters the charge generation layer. As described above, it has been found that, in a photoconductor having high printing durability and high performance characteristics, the adhesion can be improved while maintaining the performance by dispersing the particles in the charge generation layer. It was found that the dispersion stability of the charge generation layer coating solution is remarkably lowered when the particles are added, and there is a problem that image defects are caused by the aggregation of the particles.

  The present invention has been made in view of the above problems. That is, an object of the present invention is to provide an electrophotographic photoreceptor in which the adhesiveness of the photosensitive layer is kept good regardless of the size of the shrinkage, and furthermore, both good electrical characteristics and image characteristics are compatible. It is an object to provide a process cartridge and an image forming apparatus using the electrophotographic photosensitive member.

As a result of intensive studies to solve the above problems, the present inventors have found that the adhesiveness can be improved without impairing other characteristics by including a specific spherical silica in the charge generation layer. It came to.
The gist of the present invention resides in the following <1> to <10>.
<1> A volume average of primary particles which has at least a charge generation layer and a charge transport layer in this order on a conductive substrate, and the charge generation layer is produced by at least a charge generation material, a binder resin, and a sol-gel method. An electrophotographic photoreceptor comprising spherical silica particles having a particle size of 200 nm or less. (Claim 1)

<2> The electrophotographic photosensitive member according to <1>, wherein the silica particles are surface-treated with an organometallic compound having at least an aromatic hydrocarbon group. (Claim 2)

<3> The electrophotographic photosensitive member according to <1> or <2>, wherein the sphericity of the silica particles is 0.85 or more. (Claim 3)

<4> The silica particles are dispersed in 1,2-dimethoxyethane at 3% by mass, and the particle size distribution when the particle size is accumulated from the smaller one satisfies the following (formula 1): <1 The electrophotographic photosensitive member according to any one of> to <3>. (Claim 4)
(D90-D10) / D50 <0.8 (Formula 1)
(In Formula 1, D10, D50, and D90 represent the particle diameters at which the cumulative curve becomes 10%, 50%, and 90%, respectively, when the cumulative curve is determined with the total volume of the particles being 100%.)

<5> Any one of <1> to <4>, wherein the charge transport layer contains a resin having a universal hardness of 125 N / mm ² or less and an elastic deformation rate of 35% or more. The electrophotographic photoreceptor described in 1. (Claim 5)

<6> The electrophotographic photosensitive member according to any one of <1> to <5>, wherein the charge generation material contained in the charge generation layer is metal phthalocyanine. (Claim 6)

<7> The electrophotographic photosensitive member according to any one of <1> to <6>, wherein the binder resin contained in the charge generation layer is a polyvinyl acetal resin. (Claim 7)

<8> Any one of <1> to <7>, comprising an undercoat layer between the conductive substrate and the charge generation layer, wherein the undercoat layer contains a polyamide resin. The electrophotographic photoreceptor described in 1. (Claim 8)

<9> The electrophotographic photosensitive member according to any one of <1> to <8>, a charging device for charging the electrophotographic photosensitive member, and exposing the charged electrophotographic photosensitive member to electrostatic latent An electrophotographic photosensitive member comprising: an exposure device for forming an image; and at least one selected from the group consisting of a developing device for developing an electrostatic latent image formed on the electrophotographic photosensitive member cartridge. (Claim 9)

<10> The electrophotographic photosensitive member according to any one of <1> to <8>, a charging device that charges the electrophotographic photosensitive member, and an electrostatic latent image formed by exposing the charged electrophotographic photosensitive member. An image forming apparatus comprising: an exposure device for forming; and a developing device for developing an electrostatic latent image formed on the electrophotographic photosensitive member. (Claim 10)

  According to the present invention, when a specific spherical silica particle is contained in the charge generation layer, a resin having good wear resistance, relatively low hardness, and high elastic deformation rate is used as the binder resin of the charge transport layer. However, it is possible to obtain an electrophotographic photosensitive member with good adhesion that does not peel off due to contact stress with a cleaning blade or a contact-type charger. Furthermore, since the silica particles of the present invention are excellent in dispersibility in the coating liquid, the coating liquid can be kept stable, and a good electrophotographic photoreceptor free from image defects due to silica aggregates in the coating film can be obtained. Can be obtained.

1 is a schematic diagram illustrating a main configuration of an embodiment of an image forming apparatus of the present invention. It is a graph which shows the load concerning the indenter measured with the micro hardness meter, and the indentation depth.

  Hereinafter, embodiments for carrying out the present invention will be described in detail. The present invention is not limited to the following embodiments, and various modifications can be made within the scope of the invention. Further, the drawings to be used are for explaining the present embodiment, and do not represent the actual size ratio.

<Silica particles>
The silica particles of the present invention are spherical silica particles. Whether it is spherical or not is determined by whether or not the sphericity is 0.70 or more. The sphericity is preferably 0.85 or more, more preferably 0.90 or more, and most preferably 0.95 or more from the viewpoint of suppressing aggregation. “Sphericality” in the present invention is a photograph taken with an SEM, and from the observed particle area and perimeter, (sphericity) = (circumference of a circle having the same area as the particle projection area) / (particle projection) (Peripheral length of image). The closer to 1, the closer to a perfect circle. Specifically, an average value measured for 100 particles using an image processing apparatus (Sysmex Corporation: FPIA-3000) is employed.

The volume average particle size of the primary particles in the silica particles is 200 nm or less, preferably 100 nm or less, more preferably 70 nm or less in terms of the stability of the coating solution, and further 50 nm or less in terms of not inhibiting the arrival of the exposure light to the pigment. preferable. Moreover, 1 nm or more is preferable from a viewpoint of ease of handling.
The measurement of the bulk density in the silica particles is carried out using an electromagnetic vibration type bulk density measuring device (MVD-86 type) manufactured by Tsutsui Riken Kikai Co., Ltd. Specifically, the sample to be measured is put into an upper 500 μm sieve as a sample tank, the sample is dispersed through two upper and lower 500 μm sieves by electromagnetic vibration under the condition of acceleration 4G, and dropped into a 100 mL sample container. The mass density is measured, and the bulk density is calculated from the mass and volume. In order to prevent a decrease in bulk density due to its own weight, the measurement is carried out within 1 hour after dropping.

The bulk density of the silica particles measured by this method is preferably 450 g / L or less, more preferably 400 g / L or less, and most preferably 370 g / L or less from the certainty of dispersion of primary particles. Moreover, 100 g / L or more is preferable at the point of the ease of handling.
As another method for measuring the bulk density, there is a method in which a certain volume of a container is filled with silica particles, and the density is calculated using the inner volume as the volume. There are two types of bulk density calculated by this method. The mass that is lightly filled in a certain volume is called loose bulk density, and the mass that is tightly filled in the constant volume by vibration or the like is called bulk density.

The loose bulk density of the silica particles measured by this method is preferably 700 g / L or less, more preferably 500 g / L or less, and most preferably 400 g / L or less from the certainty of dispersion of primary particles. Moreover, 100 g / L or more is preferable at the point of the ease of handling.
The silica particles of the present invention are produced by a sol-gel method. As a general method for synthesizing silica particles by the sol-gel method, alcohol is eliminated by subjecting an alkoxide such as TEOS (tetraethyl orthosilicate) to a hydrolysis / polycondensation reaction under acidic or basic conditions. Methods are known. Although the reaction process is different between acidic and basic cases, in general, denser silica is more easily obtained under strongly basic conditions. Usually, since components other than silica are unnecessary, the silica is produced by separating and drying and firing only silica including the detached alcohol.

  For example, the water glass method is mentioned as a preferable method. The water glass method is a method for precipitating silica particles from water glass by ion exchange, introduction / desorption of substituents by chemical reaction, control of pH, temperature, etc. The aqueous slurry in which nanometer-order silica particles are dispersed is prepared by performing ion exchange in the above.

  The raw material silica particles have a large proportion of primary particles bonded together, but the bonds are separated in the crushing step. There are various methods in the crushing step, but preferably a method that can add an action of separating the aggregates of the aggregates is preferable, and a method that does not destroy the primary particles constituting the aggregates is preferable. ing. For example, it can be performed by a method similar to pulverization performed in a dry state, and examples thereof include a jet mill, a pin mill, and a hammer mill, and a particularly preferable method is a jet mill. The jet mill is preferably carried out by a dry method, and is an apparatus for performing pulverization by placing raw material silica particles in an air stream.

  The silica particles of the present invention are introduced with an organometallic compound having an aromatic hydrocarbon group on the surface. Examples of the organometallic coupling agent having an aromatic hydrocarbon group used for the surface treatment of silica particles include a silane coupling agent. Preferred as the silane coupling agent is a silane coupling agent having three alkoxy groups and an aromatic hydrocarbon group, and among these, three methoxy groups and one phenyl group are particularly preferred in terms of reactivity.

Furthermore, in addition to the surface treatment with a silane coupling agent, the silica fine particles may be subjected to a surface treatment with organosilazane or the like as described in Patent Document 5 in order to improve dispersibility.
The surface treatment is a process in which the hydroxyl group present on the surface of the silica particles is derived from the silane coupling agent in a process in which the surface is treated with a silane coupling agent in a liquid medium containing water (those containing alcohol in addition to water). Substituted with a group.

In the charge generation layer, the compounding ratio (mass ratio) of the charge generation material and silica particles described later is usually 10 parts by mass or more, preferably 50 parts by mass or more with respect to 100 parts by mass of the charge generation material. Is preferable for obtaining the effects of the present invention. Silica particles are usually 500
From the viewpoint of dispersion stability, it is preferably at most 300 parts by mass, preferably at most 300 parts by mass.
Silica particles may be used by being dispersed in a solvent in advance, and the particle size of the dispersion can be measured by a known method such as a weight sedimentation method or a light transmission type particle size distribution measurement method. As an example, it can be measured by a particle size analyzer (trade name: Microtrac UPA EX150) manufactured by Nikkiso Co., Ltd. When the cumulative curve is obtained with the total volume of dispersed particles being 100%, the smaller the difference between the particle diameter at the point where the cumulative curve is 10% and the particle diameter at the point where the cumulative curve is 90%, This means that the diameters are uniform, which is preferable in terms of stabilizing pigment particles in the charge generation layer.

Specifically, it is preferable that the particle size distribution when silica particles are dispersed in 1,2-dimethoxyethane at 3% by mass and the particle size is accumulated from the smaller one satisfies the following (formula 1).
(D90-D10) / D50 <0.8 (Formula 1)
(In Formula 1, D10, D50, and D90 represent the particle diameters at which the cumulative curve becomes 10%, 50%, and 90%, respectively, when the cumulative curve is determined with the total volume of the particles being 100%.)

<Charge generation layer>
The charge generation layer of the present invention is formed by binding the silica particles and the charge generation material with a binder resin. Examples of the charge generation material include inorganic photoconductive materials such as selenium and its alloys, cadmium sulfide, and organic photoconductive materials such as organic pigments, but organic photoconductive materials are preferred, especially organic pigments. Is preferred. Examples of organic pigments include phthalocyanine pigments, azo pigments, dithioketopyrrolopyrrole pigments, squalene (squarylium) pigments, quinacridone pigments, indigo pigments, perylene pigments, polycyclic quinone pigments, anthanthrone pigments, and benzimidazole pigments. . Among these, phthalocyanine pigments are particularly preferable, and metal phthalocyanine is more preferable.

  When using a phthalocyanine pigment as a charge generation material, specifically, metal-free phthalocyanine, copper, indium, gallium, tin, titanium, zinc, vanadium, silicon, germanium, aluminum or other metal or oxide thereof, halide, water Those having crystal forms of coordinated phthalocyanines such as oxides and alkoxides, and phthalocyanine dimers using oxygen atoms as bridging atoms are used. In particular, titanyl phthalocyanines (also known as oxytitanium) such as X-type, τ-type metal-free phthalocyanine, A-type (also known as β-type), B-type (also known as α-type), and D-type (also known as Y-type), which are highly sensitive crystal types Phthalocyanine), vanadyl phthalocyanine, chloroindium phthalocyanine, hydroxyindium phthalocyanine, chlorogallium phthalocyanine such as type II, hydroxygallium phthalocyanine such as type V, μ-oxo-gallium phthalocyanine dimer such as type G and type I, type II, etc. The [mu] -oxo-aluminum phthalocyanine dimer is preferred.

  Among these phthalocyanines, A-type (also known as β-type), B-type (also known as α-type), and powder X-ray diffraction angle 2θ (± 0.2 °) are 27.1 ° or 27.3 °. D-type (Y-type) titanyl phthalocyanine, II-type chlorogallium phthalocyanine, V-type and 28.1 ° have the strongest peaks, and 26.2 ° have peaks Hydroxygallium phthalocyanine having a clear peak at 28.1 ° and a full width at half maximum W of 25.9 ° of 0.1 ° ≦ W ≦ 0.4 °, G-type μ-oxo -Gallium phthalocyanine dimer and the like are particularly preferable.

The phthalocyanine compound may be a single compound or several mixed or mixed crystal states. As the mixed state that can be put in the phthalocyanine compound or crystal state here, those obtained by mixing the respective constituent elements later may be used, or they may be mixed in the production / treatment process of the phthalocyanine compound such as synthesis, pigmentation, and crystallization. It may be the one that caused the condition. As such treatment, acid paste treatment, grinding treatment, solvent treatment and the like are known. In order to generate a mixed crystal state, as described in JP-A-10-48859, two types of crystals are mixed, mechanically ground and made amorphous, and then converted into a specific crystal state by solvent treatment. The method of doing is mentioned. When organic pigments are used as the charge generating substance, usually, fine particles of these organic pigments are used in the form of a dispersion layer bound with various binder resins.

  The binder resin used for the charge generation layer is not particularly limited, but examples include polyvinyl butyral resin, polyvinyl formal resin, polyvinyl acetal type such as partially acetalized polyvinyl butyral resin in which a part of butyral is modified with formal, acetal, or the like. Resin, Polyarylate resin, Polycarbonate resin, Polyester resin, Modified ether type polyester resin, Phenoxy resin, Polyvinyl chloride resin, Polyvinylidene chloride resin, Polyvinyl acetate resin, Polystyrene resin, Acrylic resin, Methacrylic resin, Polyacrylamide resin, Polyamide Resin, polyvinyl pyridine resin, cellulosic resin, polyurethane resin, epoxy resin, silicone resin, polyvinyl alcohol resin, polyvinyl pyrrolidone resin, casein, vinyl chloride -Vinyl acetate-vinyl acetate copolymers such as vinyl acetate copolymers, hydroxy-modified vinyl chloride-vinyl acetate copolymers, carboxyl-modified vinyl chloride-vinyl acetate copolymers, vinyl chloride-vinyl acetate-maleic anhydride copolymers, etc. Insulating resins such as polymers, styrene-butadiene copolymers, vinylidene chloride-acrylonitrile copolymers, styrene-alkyd resins, silicon-alkyd resins, phenol-formaldehyde resins, poly-N-vinylcarbazole, polyvinyl anthracene, polyvinyl Examples include organic photoconductive polymers such as perylene, and polyvinyl acetal resin is particularly preferable, and polyvinyl butyral resin is preferable as the polyvinyl acetal resin. Any one of these binder resins may be used alone, or two or more thereof may be mixed and used in any combination.

  In the charge generation layer, the mixing ratio (mass) of the binder resin and the charge generation material is usually 10 parts by mass or more, preferably 30 parts by mass or more, and usually 1000 parts by mass with respect to 100 parts by mass of the binder resin. Part or less, preferably 500 parts by mass or less, and the film thickness is usually 0.1 μm or more, preferably 0.15 μm or more, and usually 10 μm or less, preferably 0.6 μm or less. If the ratio of the charge generation material is too high, the stability of the coating solution may be reduced due to aggregation of the charge generation material, while if the ratio of the charge generation material is too low, the sensitivity as a photoreceptor may be decreased. There is.

  As a method for dispersing the charge generation material, a known dispersion method such as a ball mill dispersion method, an attritor dispersion method, or a sand mill dispersion method can be used. At this time, it is effective to refine the particles to a particle size in the range of 0.5 μm or less, preferably 0.3 μm or less, more preferably 0.15 μm or less.

<Charge transport layer>
The charge transport layer contains a charge transport material and a binder resin. Furthermore, you may contain another component as needed. It can be obtained by dissolving or dispersing the charge transport material and the binder resin in a solvent to prepare a coating solution, and coating and drying on the charge generation layer.
The binder resin is preferably a resin having a universal hardness of 125 N / mm ² or less and an elastic deformation rate of 35% or more from the viewpoint of wear resistance. The universal hardness is preferably 120 N / mm ² or less, usually 80 N / mm ² or more, and preferably 100 N / mm ² or more from the viewpoint of scratch resistance. The elastic deformation rate is preferably 40% or more from the viewpoint of wear resistance and cleaning properties. Moreover, it is 90% or less normally, and 80% or less is preferable from a viewpoint of adhesiveness and solubility.

  In general, a resin having a large universal hardness has a small amount of deformation when subjected to a load by a cleaning blade or the like. On the other hand, in the case of a resin having a low universal hardness, the amount of deformation is large when the load is received by the cleaning blade, and the force can be released, so that it tends to be hard to wear. However, even if the universal hardness is small, if the elastic deformation rate is small, the permanent dent becomes large and the strain increases when a load is applied, so that the resin becomes brittle and wear increases. On the other hand, in the case of a resin having a small universal hardness and a large elastic deformation rate, it does not receive force properly, shrinks when receiving force, and easily returns to its original state when the force is removed. Abrasion resistance is improved. However, since the expansion and contraction is large as described above, there is a problem that the interface is distorted and the photosensitive layer is easily peeled off. The present invention solves this problem.

  Universal hardness and elastic deformation rate are values obtained by measuring the obtained charge transport layer coating film in an environment of a temperature of 25 ° C. and a relative humidity of 50% using a micro hardness tester (Fischer: FISCHERSCOPE H100C). . For the measurement, a Vickers square pyramid diamond indenter having a facing angle of 136 ° is used. Measurement conditions are set as follows, and the load applied to the indenter and the indentation depth under the load are continuously read, and profiles as shown in FIG. 2 plotted on the Y axis and the X axis are obtained.

<Measurement conditions>
Maximum load 5mN
Load required time 10 seconds Unloading required time 10 seconds The universal hardness is a value when pushed in with a maximum load of 5 mN, and is a value defined by the following equation from the displacement amount at that time.

Universal hardness (N / mm ² ) = maximum load (N) / surface area of Vickers indenter under maximum load (mm ² )
The elastic deformation rate is a value defined by the following formula, and is the ratio of the work that the resin performs due to elasticity at the time of unloading with respect to the total work amount required for pushing.
Elastic deformation rate (%) = (We / Wt) × 100
In the above formula, Wt represents the total work (nJ) and is represented by an area surrounded by A-B-D-A in FIG. We represents the work of elastic deformation (nJ) and is represented by the area surrounded by C-B-D-C in FIG.

The larger the elastic deformation rate, the less the deformation with respect to the load remains. The elastic deformation rate of 100% means that no deformation remains.
Examples of resins having a universal hardness of 125 N / mm ² or less and an elastic deformation rate of 35% or more include butadiene resins, styrene resins, vinyl acetate resins, vinyl chloride resins, acrylic ester resins, methacrylic ester resins, vinyl alcohol resins, Polymers and copolymers of vinyl compounds such as ethyl vinyl ether, polyvinyl butyral resin, polyvinyl formal resin, partially modified polyvinyl acetal, polycarbonate resin, polyarylate resin, polyester resin, polyamide resin, polyurethane resin, cellulose ester resin, phenoxy resin, Silicon resin, silicon-alkyd resin, poly-N-vinylcarbazole resin and the like can be mentioned, and polyarylate resin or polycarbonate resin is preferable in terms of electrical characteristics and wear resistance.

A resin having a universal hardness of 125 N / mm ² or less and an elastic deformation rate of 35% or more is usually 50% by mass or more based on the total binder resin of the charge transport layer, and 80% by mass or more from the viewpoint of wear resistance. preferable. A resin having a universal hardness larger than 125 N / mm ² or an elastic deformation rate smaller than 35% may be included as necessary.
The charge transport material is not particularly limited, and materials usually used for electrophotographic photoreceptors are used. Examples of known charge transporting materials include aromatic nitro compounds such as 2,4,7-trinitrofluorenone, cyano compounds such as tetracyanoquinodimethane, electron transporting materials such as quinone compounds such as diphenoquinone, and carbazole derivatives. , Indole derivatives, imidazole derivatives, oxazole derivatives, pyrazole derivatives, thiadiazole derivatives, heterocyclic compounds such as benzofuran derivatives, aniline derivatives, hydrazone derivatives, aromatic amine derivatives, stilbene derivatives, butadiene derivatives, enamine derivatives and multiple types of these compounds Or a hole transporting substance such as a polymer having a group consisting of these compounds in the main chain or side chain. Among these, from the viewpoint of electrical characteristics, carbazole derivatives, aromatic amine derivatives, stilbene derivatives, butadiene derivatives, enamine derivatives, and a combination of these compounds are preferable, and enamine derivatives are particularly preferable. Any one of these charge transport materials may be used alone, or two or more thereof may be used in any combination. Specific examples of the charge transport material are shown below.

  As a ratio of the binder resin and the charge transport material, the charge transport material is usually used at a ratio of 10 parts by mass or more with respect to 100 parts by mass of the binder resin. Among these, 20 parts by mass or more is preferable from the viewpoint of reducing the residual potential, and 30 parts by mass or more is more preferable from the viewpoint of stability and charge mobility when repeatedly used. On the other hand, from the viewpoint of thermal stability of the photosensitive layer, the charge transport material is usually used at a ratio of 100 parts by mass or less. Among them, 70 parts by mass or less is preferable from the viewpoint of compatibility between the charge transport material and the binder resin, 60 parts by mass or less is more preferable from the viewpoint of wear resistance, and 50 parts by mass or less is particularly preferable from the viewpoint of scratch resistance.

The thickness of the charge transport layer is not particularly limited, but is usually 5 μm or more, preferably 10 μm or more from the viewpoint of long life and sensitivity, and is usually 50 μm or less, preferably 40 μm or less, from the viewpoint of high resolution and productivity. Preferably it is 25 micrometers or less.
<Underlayer>
An undercoat layer may be provided between the conductive support and the above-described photosensitive layer in order to improve adhesion and blocking properties. As the undercoat layer, a resin, a resin in which particles such as a metal oxide are dispersed, or the like is used.

  Examples of metal oxide particles used for the undercoat layer include metal oxide particles containing one metal element such as titanium oxide, aluminum oxide, silicon oxide, zirconium oxide, zinc oxide, iron oxide, calcium titanate, titanium Examples thereof include metal oxide particles containing a plurality of metal elements such as strontium acid and barium titanate. One kind of these particles may be used alone, or a plurality of kinds of particles may be mixed and used. Among these metal oxide particles, titanium oxide and aluminum oxide are preferable, and titanium oxide is particularly preferable. The surface of the titanium oxide particles may be treated with an inorganic substance such as tin oxide, aluminum oxide, antimony oxide, zirconium oxide, or silicon oxide, or an organic substance such as stearic acid, polyol, or silicon. As the crystal form of the titanium oxide particles, any of rutile, anatase, brookite, and amorphous can be used. Moreover, the thing of the several crystal state may be contained.

Various metal oxide particle diameters can be used. Among them, the average primary particle diameter is usually 1 nm or more, preferably 10 nm, from the viewpoint of electrical characteristics and the stability of the coating liquid for forming the undercoat layer. As described above, it is usually 100 nm or less, preferably 50 nm or less.
The undercoat layer is preferably formed in a form in which metal oxide particles are dispersed in a binder resin. As the binder resin for the undercoat layer, resin materials such as polyvinyl acetal, polyamide resin, phenol resin, polyester, epoxy resin, polyurethane, and polyacrylic acid can be used. Among these, a polyamide resin having excellent adhesion to the support and low solubility in a solvent used for the charge generation layer coating solution is preferable. Of the polyamide resins, a copolymer polyamide having a cycloalkane ring structure as a constituent component is preferable, and a copolymer polyamide having a cyclohexane ring structure as a constituent component is more preferable, and among them, the following structural formula (I) is particularly preferable. A copolymerized polyamide resin having a diamine component as a constituent material is preferable.

(In formula (I), A and B each independently represent a cyclohexane ring which may have a substituent, and X represents a methylene group which may have a substituent.)
The ratio of the metal oxide particles to the binder resin used in the undercoat layer can be arbitrarily selected, but is usually 10% by mass or more and 500% by mass or less from the viewpoint of the stability of the dispersion and the coating property. It is preferable to use in the range.
The thickness of the undercoat layer can be selected arbitrarily, but is usually preferably in the range of 0.1 μm or more and 20 μm or less from the viewpoint of improving the photoreceptor characteristics and applicability.
A known antioxidant or the like may be mixed in the undercoat layer. For the purpose of preventing image defects, pigment particles, resin particles and the like may be contained and used.

<Other functional layers>
In the laminated photoreceptor, the photosensitive layer formed by the above procedure may be the uppermost layer, that is, the surface layer. However, another layer may be provided on the photosensitive layer and used as the surface layer. For example, a protective layer may be provided for the purpose of preventing the photosensitive layer from being worn out or preventing or reducing the deterioration of the photosensitive layer due to discharge products generated from a charger or the like. The photosensitive layer is preferably a surface layer because production steps can be reduced.

<Conductive support>
As the conductive support used for the photoreceptor, for example, metal materials such as aluminum, aluminum alloy, stainless steel, copper, and nickel, and conductive powders such as metal, carbon, and tin oxide are added to impart conductivity. A resin material, a resin, glass, paper, or the like on which a conductive material such as aluminum, nickel, or ITO (indium tin oxide) is deposited or applied on the surface is mainly used. As a form, a drum shape, a sheet shape, a belt shape or the like is used. For conductive support of metallic materials, for control of conductivity and surface properties, and for defect coating. A conductive material having an appropriate resistance value may be applied.

When a metal material such as an aluminum alloy is used as the conductive support, it may be used after an anodized film is applied. When an anodized film is applied, it is desirable to perform a sealing treatment by a known method.
For example, an anodic oxidation film is formed by anodizing in an acidic bath such as chromic acid, sulfuric acid, oxalic acid, boric acid, sulfamic acid, etc. give. In the case of anodic oxidation in sulfuric acid, the sulfuric acid concentration is 100 to 300 g / l, the dissolved aluminum concentration is 2 to 15 g / l, the liquid temperature is 15 to 30 ° C., the electrolysis voltage is 10 to 20 V, and the current density is 0.5 to Although it is preferable to set within the range of 2 A / dm <2>, it is not limited to the said conditions.

It is preferable to perform a sealing treatment on the anodic oxide film thus formed. The sealing treatment may be performed by a known method. For example, it is immersed in an aqueous solution containing nickel fluoride as a main component, or immersed in an aqueous solution containing nickel acetate as a main component. A high temperature sealing treatment is preferably performed.
The concentration of the nickel fluoride aqueous solution used in the case of the low-temperature sealing treatment can be appropriately selected, but more preferable results can be obtained when it is used in the range of 3 to 6 g / l. Moreover, in order to advance a sealing process smoothly, as processing temperature, it is 25-40 degreeC, Preferably it is 30-35 degreeC, Moreover, nickel fluoride aqueous solution pH is 4.5-6.5, Preferably it is 5 It is better to process in the range of .5 to 6.0. As the pH adjuster, oxalic acid, boric acid, formic acid, acetic acid, sodium hydroxide, sodium acetate, aqueous ammonia and the like can be used. The treatment time is preferably in the range of 1 to 3 minutes per 1 μm of film thickness. In order to further improve the physical properties of the film, cobalt fluoride, cobalt acetate, nickel sulfate, a surfactant or the like may be added to the nickel fluoride aqueous solution. Subsequently, it is washed with water and dried to finish the low temperature sealing treatment. As the sealing agent in the case of the high temperature sealing treatment, an aqueous solution of a metal salt such as nickel acetate, cobalt acetate, lead acetate, nickel acetate-cobalt, barium nitrate can be used, and it is particularly preferable to use nickel acetate. . The concentration in the case of using an aqueous nickel acetate solution is preferably 5 to 20 g / l. The treatment temperature is 80 to 100 ° C., preferably 90 to 98 ° C., and the pH of the nickel acetate aqueous solution is preferably 5.0 to 6.0. Here, ammonia water, sodium acetate, or the like can be used as the pH adjuster. The treatment time is 10 minutes or longer, preferably 20 minutes or longer. In this case as well, sodium acetate, organic carboxylic acid, anionic and nonionic surfactants may be added to the nickel acetate aqueous solution in order to improve the film properties. Subsequently, it is washed with water and dried to finish the high temperature sealing treatment. When the average film thickness is thick, stronger sealing conditions are required due to the higher concentration of the sealing liquid and high temperature / long-time treatment. Accordingly, productivity is deteriorated and surface defects such as spots, dirt, and dusting are likely to occur on the coating surface. From such a point, it is preferable that the average film thickness of the anodic oxide coating is usually 20 μm or less, particularly 7 μm or less.

  The support surface may be smooth, or may be roughened by using a special cutting method or polishing. Further, it may be roughened by mixing particles having an appropriate particle diameter with the material constituting the support. In order to reduce the cost, it is possible to use the drawing tube as it is without cutting. Especially when using non-cutting aluminum supports such as drawing, impact processing, ironing, etc., the process eliminates dirt, foreign matter, etc. on the surface, small scratches, etc., and a uniform and clean support can be obtained. Therefore, it is preferable.

<Method for forming each layer>
The undercoat layer of the present invention and each layer constituting the photoconductor are formed by dip coating, spray coating, nozzle coating, bar coating on a support obtained by dissolving or dispersing a substance contained in each layer in a solvent. It is formed by repeating the coating / drying step for each layer in order by a known method such as coating, roll coating, blade coating or the like.

  There are no particular restrictions on the solvent or dispersion medium used in the preparation of the coating solution, but specific examples include alcohols such as methanol, ethanol, propanol and 2-methoxyethanol, tetrahydrofuran, 1,4-dioxane, dimethoxyethane and the like. Ethers, esters such as methyl formate and ethyl acetate, ketones such as acetone, methyl ethyl ketone and cyclohexanone, aromatic hydrocarbons such as benzene, toluene and xylene, dichloromethane, chloroform, 1,2-dichloroethane, 1,1, Chlorinated hydrocarbons such as 2-trichloroethane, 1,1,1-trichloroethane, tetrachloroethane, 1,2-dichloropropane, trichloroethylene, n-butylamine, isopropanolamine, diethylamine, triethanolamine, ethylenediamine , Nitrogen-containing compounds such as triethylenediamine, acetonitrile, N- methylpyrrolidone, N, N- dimethylformamide, aprotic polar solvents such as dimethyl sulfoxide and the like. Moreover, these may be used individually by 1 type and may use 2 or more types together by arbitrary combinations and kinds.

  The amount of the solvent or dispersion medium used is not particularly limited, but considering the purpose of each layer and the properties of the selected solvent / dispersion medium, it is appropriate so that the physical properties such as solid content concentration and viscosity of the coating liquid are within a desired range. It is preferable to adjust. For example, in the case of a charge transport layer of a single layer type photoreceptor or a function separation type photoreceptor, the solid content concentration of the coating solution is usually 5% by mass or more, usually 5% by mass or more, preferably 10% by mass or more. The range is usually 40% by mass or less, preferably 35% by mass or less. Further, the viscosity of the coating solution is usually in the range of 10 cps or more, preferably 50 cps or more, and usually 500 cps or less, preferably 400 cps or less.

In the case of a charge generation layer of a multilayer photoreceptor, the solid content concentration of the coating solution is usually 0.1% by mass or more, preferably 1% by mass or more, and usually 15% by mass or less, preferably 10% by mass. % Or less. The viscosity of the coating solution is usually 0.01 cps or more, preferably 0.1 cps or more, and usually 20 cps or less, preferably 10 cps or less.
Examples of the coating method include a dip coating method, a spray coating method, a spinner coating method, a bead coating method, a wire bar coating method, a blade coating method, a roller coating method, an air knife coating method, and a curtain coating method. Other known coating methods can also be used.

<Image forming apparatus, cartridge>
An image forming apparatus such as a copying machine or a printer using the electrophotographic photosensitive member of the present invention includes at least charging, exposure, development, transfer, and static elimination processes. Also good. As shown in FIG. 1, the image forming apparatus includes an electrophotographic photosensitive member 1, a charging device 2, an exposure device 3, and a developing device 4, and further includes a transfer device 5, a cleaning device 6, and a fixing device as necessary. 7 is provided.

  The electrophotographic photosensitive member 1 is combined with one or more of the charging device 2, the exposure device 3, the developing device 4, the transfer device 5, the cleaning device 6, and the fixing device 7 to form an integrated cartridge ( The electrophotographic photosensitive member cartridge may be configured to be detachable from the main body of an electrophotographic apparatus such as a copying machine or a laser beam printer.

  Hereinafter, the embodiment of the present invention will be described more specifically with reference to examples. However, the following examples are given in order to explain the present invention in detail, and the present invention is not limited to the examples shown below without departing from the gist thereof, and can be arbitrarily modified and implemented. can do. In addition, the description of “parts” in the following examples and comparative examples indicates “parts by mass” unless otherwise specified.

[Example 1]
A coating solution for a photoreceptor was produced as follows.

[Manufacture of undercoat layer type coating solution]
The undercoat layer coating solution was prepared as follows. Rutile type titanium oxide having an average primary particle diameter of 40 nm (“TTO55N” manufactured by Ishihara Sangyo Co., Ltd.) and 3% by mass of methyldimethoxysilane (“TSL8117” manufactured by Toshiba Silicone Co., Ltd.) with respect to the titanium oxide were mixed using a Henschel mixer. The surface-treated titanium oxide obtained by mixing was dispersed by a ball mill in a mixed solvent having a mass ratio of methanol / 1-propanol of 7/3 to obtain a surface-treated titanium oxide dispersed slurry. Composition of the dispersion slurry, a mixed solvent of methanol / 1-propanol / toluene, and ε-caprolactam / bis (4-amino-3-methylcyclohexyl) methane / hexamethylenediamine / decamethylenedicarboxylic acid / octadecamethylenedicarboxylic acid The copolyamide pellets with a molar ratio of 60% / 15% / 5% / 15% / 5% are stirred and mixed with heating to dissolve the polyamide pellets, and then subjected to ultrasonic dispersion treatment. For a subbing layer with a solid content concentration of 18.0% containing a methanol / 1-propanol / toluene mass ratio of 7/1/2 and a surface-treated titanium oxide / copolymerized polyamide at a mass ratio of 3/1. A coating solution was prepared.

[Manufacture of coating solution for charge generation layer]
The charge generation layer coating solution was prepared as follows. As a charge generation material, 20 parts of Y-type (also known as D-type) oxytitanium phthalocyanine and 1,2- 1, which show a strong diffraction peak at 27.3 ° in the Bragg angle (2θ ± 0.2) in X-ray diffraction by CuKα rays. Dimethoxyethane 28
0 part was mixed and pulverized with a sand grind mill for 1 hour for atomization dispersion treatment. Subsequently, 10 parts of polyvinyl butyral (trade name “Denka Butyral” # 6000C, manufactured by Denki Kagaku Kogyo Co., Ltd.) was added to 255 parts of 1,2-dimethoxyethane and 4-methoxy-4-methyl. A binder solution obtained by dissolving in a mixed solution of 85 parts of -2-pentanone and 230 parts of 1,2-dimethoxyethane were mixed. To this was added dispersion A in which 10 parts of “silica particle 1” (manufactured by Admatechs Co., Ltd., Admanano YC100C-SP3) described in “Table-1” was dispersed in 334 parts of 1,2-dimethoxyethane. By mixing, a coating solution A for charge generation layer was prepared.

[Manufacture of coating solution for charge transport layer]
The charge transport layer coating solution was prepared as follows. 40 parts of the following charge transport material CT-1, 100 parts of the following polyarylate resin PA-1 (viscosity average molecular weight 37,000), 2 parts by weight of the following AD-1 as an antioxidant, silicone oil as a leveling agent (Shin-Etsu Silicone Co., Ltd. product name: KF-96) 0.05 part is a mixed solvent of tetrahydrofuran (hereinafter appropriately abbreviated as THF) and toluene (hereinafter appropriately abbreviated as TL) 640 parts (THF 80 mass%, TL 20 mass%). And a coating solution for charge transport layer was prepared.

[Preparation of universal hardness measurement sample and hardness measurement]
Solid content is obtained by stirring and dissolving 100 parts of polyarylate resin represented by the structural formula PA-1 and 0.05 part of silicone oil (trade name KF-96, manufactured by Shin-Etsu Silicone Co., Ltd.) in a THF / TL mixed solvent. A binder resin liquid having a concentration of 12.0% by mass was obtained. This binder resin solution was applied onto a glass plate with a heat of 4 mm so that the film thickness after drying was 18 μm, and a sample for hardness measurement was obtained.
About this sample, the value which measured the universal hardness and the elastic deformation rate by the above-mentioned method was described in the following "Table-2".

[Manufacture of photoconductor]
On the 3003 series aluminum alloy tube having a diameter of 30 mm, a length of 246 mm, and a wall thickness of 0.75 mm, the thickness of the undercoat layer coating liquid obtained as described above is about 1.5 μm after drying. And an undercoat layer was provided by drying at room temperature.

Subsequently, the charge generation layer coating solution A obtained as described above is dip-coated on the undercoat layer so that the film thickness after drying is about 0.3 μm, and dried at room temperature. A charge generation layer was provided.
Subsequently, the above-described charge transport layer coating solution was dip-coated on the charge generation layer so that the film thickness after drying was about 18 μm, to prepare a photosensitive drum A.
[Example 2]
In Example 1, when the charge generation layer coating solution was adjusted, the charge generation layer coating thickness after coating was 0 using the charge generation layer coating solution B adjusted by doubling the addition amount of the silica particle dispersion A. A photosensitive drum B was produced in the same manner as in Example 1 except that the coating was applied to a thickness of 35 μm.

[Example 3]
In Example 2, except that the charge generation layer coating liquid C was applied using the charge generation layer coating liquid C in which the silica concentration of the silica particle dispersion was doubled, so that the thickness of the charge generation layer after coating was 0.4 μm. The same operation as in No. 2 was performed to prepare a photoconductor drum C.

[Example 4]
In Example 2, instead of “Silica Particle 1”, “Silica Particle 2” described in the following “Table-1” (manufactured by Admatechs Co., Ltd., Admanano YA050C-SP3) was used. Except that the liquid D was used, the same operation as in Example 2 was performed to prepare a photosensitive drum D.

[Example 5]
In Example 2, instead of “Silica particle 1”, “silica particle 3” (manufactured by Admatechs Co., Ltd., Admanano YA010C-SP3) described in the following “Table-1” was used for charge generation layer coating A photoconductor drum E was produced in the same manner as in Example 2 except that the liquid E was used.

[Comparative Example 1]
A photosensitive drum F was produced in the same manner as in Example 1 except that the charge generation layer coating solution F to which no silica particles were added was used.

[Comparative Example 2]
In Example 2, instead of “silica particles 1”, the charge generation layer coating solution G prepared using “silica particles 4” (AEROSIL R972, manufactured by Nippon Aerosil Co., Ltd.) described in “Table-1” below. A photosensitive drum G was produced in the same manner as in Example 2 except that was used.

[Comparative Example 3]
In Example 2, instead of “silica particles 1”, “silica particles 5” described in “Table-1” (Aerosil RA200HS, manufactured by Nippon Aerosil Co., Ltd.) was used, and the charge generation layer coating solution H was prepared. A photosensitive drum H was produced in the same manner as in Example 2 except that was used.

[Comparative Example 4]
In Example 2, a charge generation layer prepared using “silica particles 6” described in “Table-1” below (amorphous silica particle Seahoster KE-P50 manufactured by Nippon Shokubai Co., Ltd.) instead of “silica particles 1” Except that the coating liquid I was used, the same operation as in Example 2 was performed to prepare a photosensitive drum I.

[Example 6]
In Example 2, the same operation as in Example 2 was performed except that (PA-2) having the following structure was used instead of the polyarylate resin (PA-1) as the binder resin of the charge transport layer, and the photosensitive drum J was prepared. Produced. About (PA-2), the value which measured the universal hardness and the elastic deformation rate by the method similar to Example 1 was described in the following "Table-2."

[Comparative Example 5]
In Example 6, the same operation as in Example 6 was performed without adding the silica particles 1, and a photosensitive drum K was produced.

[Example 7]
In Example 2, the same operation as in Example 2 was performed except that the following structural polycarbonate resin (PC-1) was used instead of the polyarylate resin (PA-1) as the binder resin of the charge transport layer, and the photosensitive drum L Was made. About (PC-1), the value which measured the universal hardness and the elastic deformation rate by the method similar to Example 1 was described in the following "Table-2."

[Comparative Example 6]
In Example 7, the same operation as in Example 7 was performed without adding the silica particles 1, and a photoconductive drum M was produced.
The physical properties of the silica particles used in Examples and Comparative Examples are shown in “Table-1” below. The bulk density is a value measured by a method (loose bulk density) in which a certain volume of a container is lightly filled with silica particles and the inner volume is calculated as a volume. The sphericity of silica particles 1, 2, and 3 was 91%, 91%, and 88%, respectively.

  The values of universal hardness and elastic deformation rate of the binder resin for charge transport layer used in Examples and Comparative Examples measured by the above-mentioned methods are shown in “Table-2” below.

<Electrical characteristics test>
The attenuation characteristics of the surface potential when a specific amount of light was irradiated were measured as follows. Using an electrophotographic characteristic evaluation apparatus manufactured according to the electrophotographic society measurement standards (basic and applied electrophotographic technology, edited by Electrophotographic Society, Corona, page 404-405), temperature 25 ° C., relative humidity 50% In this environment, the drum is rotated at a constant rotation speed of 95 rpm, the charging (scorotron charger) conditions are fixed so that the initial surface potential of the photoreceptor is about −700 V, and the light of the halogen lamp is 780 nm monochromatic with an interference filter. The surface potential VL (unit: -V) was measured when the light was exposed using an ND filter with an amount of light of 0.27 μJ / cm ² . VL is so preferable that the absolute value of a value is small. The results are shown in “Table-3”.

<Adhesion test>
On the photosensitive drum produced in the example, an NT cutter was used to cut 6 pieces vertically and 6 pieces horizontally at intervals of 2 mm to produce 5 × 5 25 squares. A cellophane tape (3M) was adhered and adhered from above, and the adhesion between the photosensitive layer (charge generation layer) and the undercoat layer was tested by pulling it up to 90 ° with respect to the adhesion surface. This was performed at two locations, and the ratio of the number of the photosensitive layer mass remaining on the support was evaluated as the residual rate out of the total 50 masses. The larger the number of remaining masses, the higher the residual rate and the better the adhesiveness. The results are shown in “Table-3”.

<Stability of coating solution for charge generation layer>
The state of the liquid after the charge generation layer coating solution prepared in each Example and Comparative Example was allowed to stand in an environment of 25 ° C. for 7 days was observed, and the results are shown in “Table-3”.

  As can be seen from the above table, generally, when particles are added to the charge generation layer, the light attenuation is inhibited and the surface potential is hardly lowered. However, when the silica particles of the present invention are added, there is almost no deterioration in light attenuation. The characteristics are shown. Moreover, it turns out that by containing the silica particle of this invention, adhesiveness improves markedly compared with the time of not containing. Even when silica particles other than those of the present invention of Comparative Examples 2 to 4 are contained, improvement in adhesiveness is observed, but in the charge generation layer coating liquid, precipitates are confirmed within one week, and the stability is inferior. I understand that.

<Image test>
The produced photosensitive drum A was mounted on a black drum cartridge for a color printer MICROLINE Pro 9800PS-E manufactured by Oki Data. Next, a developing toner (volume average particle size 7.05 μm, Dv / Dn = 1.14, average circularity 0. 10 μm) manufactured according to the manufacturing method (emulsion polymerization aggregation method) of developing toner A disclosed in Japanese Patent Application Laid-Open No. 2007-213050. 963) was mounted on a black toner cartridge. These drum cartridges and toner cartridges were mounted on the printer.

Specifications of MICROLINE Pro 9800PS-E Quadruple Tandem Color 36ppm, Monochrome 40ppm
1200 dpi
Contact roller charging (DC voltage applied)
LED exposure With static elimination light When 10,000 sheets of images were formed in an environment of a temperature of 35 ° C. and a humidity of 80%, good images were obtained without defects due to photoreceptor contamination or film peeling.

1 Photoconductor (Electrophotographic photoconductor)
2 Charging device (charging roller; charging unit)
3 Exposure equipment (exposure section)
4 Development device (development unit)
DESCRIPTION OF SYMBOLS 5 Transfer apparatus 6 Cleaning apparatus 7 Fixing apparatus 41 Developing tank 42 Agitator 43 Supply roller 44 Developing roller 45 Control member 71 Upper fixing member (fixing roller)
72 Lower fixing member (fixing roller)
73 Heating device T Toner P Recording paper (paper, medium)

Claims (10)

  The conductive particles have at least a charge generation layer and a charge transport layer in this order, and the charge generation layer is produced by at least a charge generation material, a binder resin, and a sol-gel method. An electrophotographic photoreceptor comprising spherical silica particles of 200 nm or less.   2. The electrophotographic photoreceptor according to claim 1, wherein the silica particles are surface-treated with an organometallic compound having at least an aromatic hydrocarbon group.   The electrophotographic photosensitive member according to claim 1, wherein the sphericity of the silica particles is 0.85 or more. The particle size distribution when the silica particles are dispersed in 1,2-dimethoxyethane at 3% by mass and the particle size is accumulated from the smaller one satisfies the following (Equation 1): The electrophotographic photosensitive member according to any one of the above.
(D90-D10) / D50 <0.8 (Formula 1)
(In Formula 1, D10, D50, and D90 represent the particle diameters at which the cumulative curve becomes 10%, 50%, and 90%, respectively, when the cumulative curve is determined with the total volume of the particles being 100%.) 5. The electrophotography according to claim 1, wherein the charge transport layer contains a resin having a universal hardness of 125 N / mm ² or less and an elastic deformation rate of 35% or more. Photoconductor.   The electrophotographic photosensitive member according to claim 1, wherein the charge generation material contained in the charge generation layer is metal phthalocyanine.   The electrophotographic photoreceptor according to any one of claims 1 to 6, wherein the binder resin contained in the charge generation layer is a polyvinyl acetal resin.   The electrophotography according to claim 1, further comprising an undercoat layer between the conductive substrate and the charge generation layer, wherein the undercoat layer contains a polyamide resin. Photoconductor.   The electrophotographic photosensitive member according to any one of claims 1 to 8, a charging device for charging the electrophotographic photosensitive member, and exposure for forming an electrostatic latent image by exposing the charged electrophotographic photosensitive member. An electrophotographic photosensitive member cartridge comprising: an apparatus; and at least one selected from the group consisting of a developing device that develops an electrostatic latent image formed on the electrophotographic photosensitive member.   The electrophotographic photosensitive member according to any one of claims 1 to 8, a charging device that charges the electrophotographic photosensitive member, and an exposure device that exposes the charged electrophotographic photosensitive member to form an electrostatic latent image, An image forming apparatus comprising: a developing device that develops the electrostatic latent image formed on the electrophotographic photosensitive member.

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