Electrophotographic photoreceptor, process cartridge, electrophotographic device, and method for manufacturing electrophotographic photoreceptor

Abstract

To provide an electrophotographic photoreceptor capable of minimizing density unevenness.SOLUTION: A first layer contains a support material, binder resin, gallium phthalocyanine pigment, and perinone compound selected from a group consisting of compounds represented by a formula (1) and formula (2), and a second layer contains the binder resin and the gallium phthalocyanine pigment.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an electrophotographic photosensitive member, a process cartridge using the electrophotographic photosensitive member, an electrophotographic apparatus, and a method for manufacturing the electrophotographic photosensitive member. [Background technology]

[0002] 2. Description of the Related Art As one type of electrophotographic photoreceptor, a laminated type photoreceptor is known, which is formed by laminating a charge generating layer containing a charge generating substance and a charge transport layer containing a charge transport substance.

[0003] The charge generating layer of the multi-layer photoreceptor can be used as a single layer, but a technique of using it as a plurality of separate layers for the purpose of improving performance is also known.

[0004] Patent Document 1 discloses a photoreceptor that has photosensitivity to both a semiconductor laser light source for digital use that has spectral characteristics in the range of around 780 to 800 nm and a white light source for analog use, by separately laminating disazo pigments with different spectral characteristics as a charge generation layer.

[0005] Patent Document 2 discloses a technology for providing a photosensitive layer with rectifying properties and ensuring electrical properties by functionally separating the function of the charge generation layer into a layer having an n-type semiconductor pigment that has been treated with active energy rays and / or an active gas, and a layer having a p-type semiconductor pigment that has been similarly treated on the charge transport layer side.

[0006] Patent Document 3 focuses on the fact that contact between a charge transport material and a charge generation material at the interface between the charge transport layer and the charge generation layer has a significant effect on quantum efficiency, and discloses a technology in which layers having different content ratios of vanadyl phthalocyanine, which is used as a charge generation material, are stacked one on top of the other in the charge generation layer, and the concentration of the charge generation material in the film on the charge transport layer side is increased compared to the layer on the substrate side, thereby obtaining a photoreceptor with high sensitivity and low residual potential.

[0007] Patent Document 4 addresses the issue of sensitivity reduction due to an increase in surface charge density accompanying an increase in capacitance when the film thickness is reduced due to mechanical wear after long-term repeated use, by providing multiple layers with different sensitivities that adjust the penetration depth of incident light in the photosensitive layer, thereby disclosing a photoreceptor that can be used while maintaining sensitivity even when the film thickness is reduced after long-term repeated use. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Publication No. 05-040352 [Patent Document 2] Japanese Patent Application Publication No. 10-268533 [Patent Document 3] Japanese Patent Application Publication No. 07-020645 [Patent Document 4] Japanese Patent Application Laid-Open No. 2002-139851 Summary of the Invention [Problem to be solved by the invention]

[0009] However, when a charge generating layer is used in a laminated configuration, it has been found that an increase in the amount of charge generating material in the layer causes a problem of increased local dark decay. Specifically, increased dark decay can cause a fogging phenomenon in non-image areas (a phenomenon in which toner is developed in areas where the charge potential is low). Furthermore, the occurrence of areas where dark decay is locally increased within the surface can cause unevenness (mottle) in the charge potential and exposure potential, which can worsen the graininess of the image when the halftone image is output (hereinafter also referred to as "uneven density of the halftone image").

[0010] An object of the present invention is to provide an electrophotographic photoreceptor that, when a charge generating layer is formed by laminating a laminated type photosensitive layer, sufficiently suppresses in-plane unevenness in dark attenuation and achieves the high level of image quality that has been demanded in recent years, and a process cartridge and an electrophotographic apparatus that use the electrophotographic photoreceptor. [Means for solving the problem]

[0011] The above object can be achieved by the present invention, which provides an electrophotographic photoreceptor having a support, a first layer, a second layer, and a charge transport layer in this order, The first layer contains a binder resin, a gallium phthalocyanine pigment, and at least one perinone compound selected from the group consisting of perinone compounds represented by the following formula (1) and perinone compounds represented by the following formula (2): The second layer is an electrophotographic photoreceptor characterized in that it contains a binder resin and a gallium phthalocyanine pigment. [ka] [ka] In formula (1), R 11 ~R 18 In formula (2), R 21 ~R 28 R each independently represents a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted aryloxy group, or a substituted or unsubstituted alkoxycarbonyl group. 11 ~R 14 , R 15 ~R 18 , R 21 ~R 24 and R 25 ~R 28 Adjacent groups in each group may be linked together to form a ring.

[0012] The present invention also provides a process cartridge that integrally supports the electrophotographic photosensitive member and at least one means selected from the group consisting of a charging means, a developing means, and a cleaning means, and is detachably mountable to the main body of an electrophotographic apparatus.

[0013] The present invention also provides an electrophotographic apparatus having the above electrophotographic photosensitive member, a charging means, an exposure means, a developing means and a transfer means.

[0014] The present invention also provides a method for producing an electrophotographic photoreceptor having a support, a first layer, a second layer, and a charge transport layer in this order, comprising the steps of: The manufacturing method comprises: a step of preparing a coating liquid for a first layer, the coating liquid containing a binder resin and / or a monomer for the binder resin, a gallium phthalocyanine pigment, and at least one perinone compound selected from the group consisting of the compound represented by the above formula (1) and the compound represented by the above formula (2); a step of forming a coating film of the coating liquid for the first layer on the support, and drying and / or curing the coating film of the coating liquid for the first layer to form the first layer on the support; a step of preparing a coating liquid for a second layer containing a binder resin and / or a monomer for the binder resin, and a gallium phthalocyanine pigment; forming a coating film of the second layer coating liquid on the second layer and drying and / or curing the coating film of the second layer coating liquid to form the second layer on the first layer; and forming the charge transport layer on the second layer; The method for producing an electrophotographic photosensitive member is characterized by comprising the steps of: [Effects of the Invention]

[0015] According to the present invention, it is possible to provide an electrophotographic photosensitive member that sufficiently suppresses in-plane dark attenuation unevenness and suppresses density unevenness in halftone images at a high level, as has been demanded in recent years, a process cartridge and an electrophotographic apparatus that use such an electrophotographic photosensitive member, and a method for manufacturing such an electrophotographic photosensitive member. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a diagram showing an example of a layer structure of an electrophotographic photosensitive member according to the present invention. [Figure 2] 1 is a diagram showing an example of a schematic configuration of an electrophotographic apparatus provided with a process cartridge having an electrophotographic photosensitive member according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0017] The present invention will be described in detail below with reference to preferred embodiments. [Electrophotographic photoreceptor] The electrophotographic photoreceptor of the present invention has a support and a laminated photosensitive layer formed on the support. Fig. 1 is a diagram showing an example of the layer structure of an electrophotographic photoreceptor. In Fig. 1, 101 is the support, 102 is an undercoat layer, 103 is a first layer, and 104 is a second layer. 105 is a charge transport layer. In the present invention, the undercoat layer 102 may be omitted.

[0018] <Support> The support is preferably one that is conductive (conductive support), and examples thereof include supports made of metals (alloys) such as aluminum, iron, copper, gold, stainless steel, and nickel, metals with conductive coatings on their surfaces, and insulating supports. Examples of insulating supports include supports made of plastics such as polyester resin, polycarbonate resin, and polyimide resin, as well as glass and paper. Examples of conductive coatings include thin metal films such as aluminum, chromium, silver, and gold, thin films of conductive materials such as indium oxide, tin oxide, and zinc oxide, and thin films of conductive inks containing silver nanowires.

[0019] The shape is preferably cylindrical. The surface of the support may be subjected to electrochemical treatment such as anodization, blasting, cutting, or the like.

[0020] The shape of the support may be, for example, cylindrical or film-like. Among these, a cylindrical aluminum support is superior in terms of mechanical strength, electrophotographic properties, and cost. A raw tube may be used as the support as is, but the surface of the raw tube may be subjected to physical treatment such as cutting, honing, or blasting, or to chemical treatment using an acid or the like, in order to improve electrical properties or suppress interference fringes, and then the resulting support may be used.

[0021] <Conductive layer> The conductive layer is a layer that may be provided if necessary. The conductive layer is a layer that may be disposed on the conductive support and between the conductive support and the photosensitive layer, more specifically, the conductive support, the conductive layer, the undercoat layer, and the photosensitive layer in this order. By providing the conductive layer, scratches and irregularities on the surface of the conductive support can be concealed and light reflection on the surface of the support can be controlled. The conductive layer contains conductive particles and a resin.

[0022] Examples of the material of the conductive particles include metal oxides, metals, and carbon black. Examples of metal oxides include zinc oxide, aluminum oxide, indium oxide, silicon oxide, zirconium oxide, tin oxide, titanium oxide, strontium titanate, magnesium oxide, antimony oxide, and bismuth oxide. Among these, metals include aluminum, nickel, iron, nichrome, copper, zinc, and silver. Of the above materials for the conductive particles, metal oxides are preferred, and titanium oxide, tin oxide, and zinc oxide are particularly preferred. Furthermore, with regard to the metal oxide, the surface of the metal oxide may be treated with a silane coupling agent or the like, or may be doped with an element such as phosphorus or aluminum itself or an oxide thereof. The conductive particles may have a layered structure including a core material and a coating layer covering the core material. Examples of the core material include titanium oxide, barium sulfate, and zinc oxide. Examples of the coating layer include metal oxides such as tin oxide. The coating layer and the surface treated with the silane coupling agent are much thicker than each other. When metal oxide particles are used as the conductive particles, the volume average particle size thereof is preferably 1 nm or more and 500 nm or less, and more preferably 3 nm or more and 400 nm or less.

[0023] Examples of the resin include polyester resin, polycarbonate resin, polyvinyl acetal resin, acrylic resin, silicone resin, epoxy resin, melamine resin, polyurethane resin, phenol resin, and alkyd resin. Furthermore, the conductive layer may contain silicone oil, resin particles, a masking agent such as titanium oxide, and the like.

[0024] The conductive layer can be obtained by providing a coating film of a coating liquid for conductive layer containing the above-mentioned materials and solvent on a support and drying the coating film.

[0025] Examples of the solvent used in the coating liquid include alcohol-based solvents, sulfoxide-based solvents, ketone-based solvents, ether-based solvents, ester-based solvents, and aromatic hydrocarbon-based solvents.

[0026] Examples of a method for dispersing the conductive particles in the coating liquid for the conductive layer include methods using a paint shaker, a sand mill, a ball mill, and a liquid collision type high-speed disperser.

[0027] The average thickness of the conductive layer is preferably 0.1 μm or more and 50 μm or less, and particularly preferably 3 μm or more and 40 μm or less.

[0028] <Undercoat layer> An undercoat layer having a barrier function or an adhesive function may be provided on the support or the conductive layer, if necessary. The undercoat layer is obtained by dissolving a resin in a solvent to prepare a coating liquid for the undercoat layer, forming a coating film of the coating liquid for the undercoat layer, and drying the coating film. The undercoat layer contains a resin and a substance that improves electrical properties. Each of these will be explained below.

[0029] The undercoat layer contains a resin. The resin may be obtained as a cured film by polymerizing a composition containing a monomer having a polymerizable functional group in a coating liquid to form a coating film (curing by polymerization of the monomer) from the coating liquid.

[0030] Examples of the resin include polyester resin, polycarbonate resin, polyvinyl acetal resin, acrylic resin, epoxy resin, melamine resin, polyurethane resin, phenol resin, polyvinylphenol resin, alkyd resin, polyvinyl alcohol resin, polyethylene oxide resin, polypropylene oxide resin, polyamide resin, polyamic acid resin, polyimide resin, polyamideimide resin, and cellulose resin.

[0031] Examples of the polymerizable functional group possessed by the monomer having a polymerizable functional group include an isocyanate group, a blocked isocyanate group, a methylol group, an alkylated methylol group, an epoxy group, a metal alkoxide group, a hydroxyl group, an amino group, a carboxyl group, a thiol group, a carboxylic anhydride group, and a carbon-carbon double bond group.

[0032] Furthermore, for the purpose of improving electrical properties, the undercoat layer contains an electron transporting material, a metal oxide, a metal, etc. Among these, it is preferable to use an electron transporting material or a metal oxide. Examples of the electron transport substance include a quinone compound, an imide compound, a benzimidazole compound, a cyclopentadienylidene compound, a fluorenone compound, a xanthone compound, a benzophenone compound, a cyanovinyl compound, an aryl halide compound, a silole compound, a boron-containing compound, etc. An electron transport substance having a polymerizable functional group may be used as the electron transport substance, and the undercoat layer may be formed as a cured film by copolymerizing the electron transport substance with the above-mentioned monomer having the polymerizable functional group. Examples of metal oxides include indium tin oxide, tin oxide, indium oxide, titanium oxide, zinc oxide, aluminum oxide, strontium titanate, silicon dioxide, etc. Examples of metals include gold, silver, aluminum, etc.

[0033] The metal oxide contained in the undercoat layer may be surface-treated with a surface treatment agent such as a silane coupling agent. The metal oxide surface treatment can be carried out by a common method, such as a dry method or a wet method. In the dry method, a metal oxide is stirred in a mixer capable of high-speed stirring, such as a Henschel mixer, while an alcohol aqueous solution, an organic solvent solution, or an aqueous solution containing a surface treatment agent is added to the metal oxide to uniformly disperse the mixture, followed by drying. In the wet method, the metal oxide and the surface treatment agent are stirred in a solvent or dispersed in a sand mill using glass beads or the like, and after dispersion, the solvent is removed by filtration or vacuum distillation. After the solvent is removed, it is preferable to further bake the mixture at 100°C or higher.

[0034] The undercoat layer may further contain additives, for example, known materials such as metal powder such as aluminum, conductive substances such as carbon black, metal chelate compounds, and organometallic compounds.

[0035] The undercoat layer can be formed by preparing a coating solution for the undercoat layer containing the above-mentioned materials and solvent, forming the coating film on the support or the conductive layer, and drying and / or curing it.

[0036] Examples of the solvent used in the coating liquid for the undercoat layer include organic solvents such as alcohols, sulfoxides, ketones, ethers, esters, halogenated aliphatic hydrocarbons, aromatic compounds, etc. In the present invention, it is preferable to use alcohol-based and ketone-based solvents.

[0037] Dispersion methods for preparing the coating liquid for the undercoat layer include methods using a homogenizer, ultrasonic disperser, ball mill, sand mill, roll mill, vibration mill, attritor, and liquid collision type high-speed disperser.

[0038] When an undercoat layer is used, the average thickness thereof is preferably from 0.05 μm to 50 μm, and more preferably from 0.3 μm to 25 μm.

[0039] <First layer and second layer> The electrophotographic photoreceptor of the present invention has a first layer containing a binder resin, a gallium phthalocyanine pigment, and a perinone compound, and a second layer containing a binder resin and a gallium phthalocyanine pigment.

[0040] In electrophotographic image forming apparatuses, a method of reproducing halftones using a screen pattern is commonly used to reproduce the halftones of an image. However, the reproducibility of halftone dots in highlight areas is unstable, which is perceived as noise and leads to poor graininess. One cause of this instability is uneven charging of the photoreceptor. Uneven charging of the photoreceptor occurs when, for some reason, microscopic unevenness occurs in the charging potential within the surface of the photoreceptor, resulting in uneven in-plane exposure potential during image exposure, which in turn leads to unstable halftone dot reproducibility and poor graininess.

[0041] Such microscopic unevenness in the charge potential becomes more pronounced when the charge generating layer is used in a laminated configuration. That is, an increase in the absolute amount of charge generating material in the layer causes in-plane unevenness in dark decay, which leads to unevenness in the charge potential and to deterioration of graininess.

[0042] As a result of investigations, the present inventors have found that by using a first layer containing a binder resin, a gallium phthalocyanine pigment, and at least one perinone compound selected from the group consisting of perinone compounds represented by formula (1) and perinone compounds represented by formula (2) separately from a second layer containing a binder resin and a gallium phthalocyanine pigment, it is possible to suppress in-plane dark attenuation unevenness and obtain an image with good graininess.

[0043] The inventors believe that this configuration can suppress charging unevenness, i.e., dark decay unevenness, as follows: One of the causes of deterioration of dark decay in photoreceptors is the injection of "thermally excited carriers" generated from the charge-generating material in the charge-generating layer into the charge-transport layer. Organic pigments used as charge-generating materials have energy bands due to the overlapping of molecules. Because organic pigments are not as crystalline as inorganic pigments, they have bands consisting of multiple levels corresponding to the overlapping pattern of multiple molecules. Among these levels, there are levels that are excited by heat at around room temperature. Therefore, even in an unexposed state, thermally excited carriers are generated in the charge-generating layer of the photoreceptor at room temperature. These carriers are injected into the charge-transport layer in response to the electric field during charging, which is thought to lower the surface charge potential.

[0044] Since the number of thermally excited carriers increases as the amount of charge generating material in a layer increases, the dark decay amount is larger when a laminated layer is used than when a single layer is used.

[0045] Furthermore, since the charge generating material is dispersed in the film as a pigment, an excess of thermally excited carriers is distributed within the surface according to the distribution of the pigment in the film, and it is thought that unevenness in dark decay occurs within the surface according to this distribution.

[0046] The inventors believe that the reason why dark decay can be suppressed in the present invention by mixing a perinone compound with a film having a gallium phthalocyanine pigment as a charge generating material is that the wide electron conjugated system of the perinone compound interferes with the band that generates thermally excited carriers in the nearby gallium phthalocyanine pigment, thereby promoting recombination.

[0047] The ability to suppress dark decay unevenness varies depending on the amount of perinone compound and gallium phthalocyanine pigment added and the film thickness. The preferred ranges for these are as follows:

[0048] (Suitable range for the first layer) The content of the perinone compound in the first layer is preferably 50% by mass or more and 1000% by mass or less relative to the content of the gallium phthalocyanine pigment. If this content is less than 50% by mass, the dark decay suppression effect envisioned in the present invention cannot be obtained, and if it exceeds 1000% by mass, potential fluctuations deteriorate. If the perinone is present in excess of the gallium phthalocyanine pigment, it is thought that the generation of not only thermally excited carriers but also carriers generated by exposure is inhibited, thereby worsening potential fluctuations.

[0049] Furthermore, the effects of the present invention are enhanced when the content of the gallium phthalocyanine pigment in the first layer is 5% by mass or more and 50% by mass or less relative to the total mass of the first layer. If it is less than 5% by mass, the gallium phthalocyanine pigment itself does not have sufficient charge generation ability, and potential fluctuations worsen due to carriers remaining in the film, making it unsuitable for long-term use. If the ratio of the gallium phthalocyanine pigment in the film exceeds 50% by mass, the dark decay suppression effect of perinone cannot be obtained, and the worsening dark decay leads to worsening granularity.

[0050] Furthermore, the thickness of the first layer is preferably 2 μm or more and 20 μm or less. If the thickness of the first layer is thinner than 2 μm, dark attenuation due to local hole injection increases, resulting in worsened granularity. Although the effect of the present invention can be obtained to a great extent even if the thickness is thicker than 20 μm, a thickness greater than this will adversely affect film formability.

[0051] (Suitable range for the second layer) The second layer may contain a perinone compound, but the content of the perinone compound is preferably 1% by mass or less relative to the content of the gallium phthalocyanine pigment. If the content of the perinone compound exceeds 1% by mass, long-term potential fluctuation deteriorates. This is thought to be because the presence of a large amount of perinone compound at the interface between the charge transport layer and the charge generation layer inhibits the transfer of positive charges from the charge generation layer to the charge transport layer.

[0052] Furthermore, the content of the gallium phthalocyanine pigment in the second layer is preferably 50% by mass or more and 75% by mass or less, based on the total mass of the second layer. This range improves granularity. If the content of the gallium phthalocyanine pigment is less than 50% by mass, sensitivity deteriorates. If it exceeds 75% by mass, the increase in dark decay due to the second layer exceeds the dark decay suppression effect of the perinone supported by the first layer, resulting in poor granularity.

[0053] The thickness of the second layer is preferably 0.1 μm or more and 0.5 μm or less. If the thickness is thinner than 0.1 μm, film-forming properties deteriorate. If the thickness is thicker than 0.5 μm, dark attenuation deteriorates and the effect of improving graininess decreases.

[0054] (Gallium phthalocyanine pigment) The charge generating material contains a hydroxygallium phthalocyanine pigment or a chlorogallium phthalocyanine pigment (hereinafter, these two types are also collectively referred to as "phthalocyanine pigments"), which may have an axial ligand or a substituent.

[0055] The hydroxygallium phthalocyanine pigment is preferably a hydroxygallium phthalocyanine crystal having a crystal form which exhibits strong peaks at Bragg angles (2θ±0.2°) of 7.3°, 24.9°, and 28.1° in CuKα characteristic X-ray diffraction; a hydroxygallium phthalocyanine crystal having strong peaks at Bragg angles (2θ±0.2°) of 7.5°, 9.9°, 12.5°, 16.3°, 18.6°, 25.1°, and 28.3°; or a hydroxygallium phthalocyanine crystal having strong peaks at Bragg angles (2θ±0.2°) of 7.5°, 9.9°, 12.5°, 16.3°, 18.6°, 25.1°, and 28.3°.

[0056] The chlorogallium phthalocyanine is preferably a chlorogallium phthalocyanine crystal having strong peaks at Bragg angles (2θ±0.2°) of 7.4°, 16.6°, 25.5°, and 28.2° in CuKα characteristic X-ray diffraction; a chlorogallium phthalocyanine crystal having strong peaks at Bragg angles (2θ±0.2°) of 6.8°, 17.3°, 23.6°, and 26.9°; or a chlorogallium phthalocyanine crystal having strong peaks at Bragg angles (2θ±0.2°) of 8.7°, 9.2°, 17.6°, 24.0°, 27.4°, and 28.8°.

[0057] (Perinone compounds) The perinone compound in the present invention is at least one compound selected from the group consisting of perinone compound (1) and perinone compound (2). Perinone compound (1) is a compound represented by the following formula (1). Perinone compound (2) is a compound represented by the following formula (2). [ka] [ka] In formula (1), R 11 ~R 18 and in formula (2), R 21 ~R 28 R each independently represents a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted aryloxy group, or a substituted or unsubstituted alkoxycarbonyl group. 11 ~R 14 , R 15 ~R 18 , R 21 ~R 24 and R 25 ~R 28 Adjacent groups in each group may be linked together to form a ring.

[0058] The alkyl group is a straight-chain or branched alkyl group having 1 to 10 atoms in the main chain. In particular, from the viewpoint of suppressing graininess, a branched alkyl having 3 to 10 carbon atoms is preferred.

[0059] R in Equation (1) 11 ~R 18 is R in Eq. (3). 31 and R 32 As shown in the formula (5), it is preferable that each independently be a branched alkyl group having 3 to 10 carbon atoms. 51 ~R 56 As shown in formula (6), each independently is preferably a methyl group, an ethyl group, or a propyl group. R in Equation (2) 21 ~R 28 is R in Eq. (4). 41 and R 42 As shown in the formula (6), it is preferable that each independently be a branched alkyl having 3 to 10 carbon atoms. 61 ~R 66 It is more preferable that each independently represents a methyl group, an ethyl group, or a propyl group, as shown by the following formula:

[0060] [ka] [ka] [ka] [ka]

[0061] In the above formulas (1) and (2), Examples of the substituent on the alkyl group include a halogen atom, an aryl group, and an alkoxycarbonyl group. Examples of the substituent on the aryl group include a halogen atom, an alkyl group, and an alkoxycarbonyl group. An aryl group having 6 to 10 carbon atoms is preferred, and a phenyl group is particularly preferred. Examples of the substituent on the aryloxy group include a halogen atom, an alkyl group, and an alkoxycarbonyl group. An aryloxy group having 6 to 10 carbon atoms is preferred, and a phenyloxy group is particularly preferred. Examples of the substituent of the alkoxycarbonyl group include a halogen atom and an aryl group. An alkoxycarbonyl group having 1 to 10 carbon atoms is preferred, and a methoxycarbonyl group, an ethoxycarbonyl group, and a propoxycarbonyl group are particularly preferred. R 11 ~R 14 , R 15 ~R 18 , R 21 ~R 24 and R 25 ~R 28 Adjacent groups in each group may be linked together to form a ring, and it is particularly preferred that they form an aromatic ring, and the aromatic ring is particularly preferably a naphthalene ring or an anthracene ring.

[0062] Specific examples (1-1) to (1-17) of the perinone compound (1) and specific examples (2-1) to (2-17) of the perinone compound (2) are shown below, but the present embodiment is not limited thereto.

[0063] [ka]

[0064] [ka]

[0065] The first layer and the second layer according to the present invention are produced by the following method. The first layer is obtained by dispersing a binder resin and / or a monomer for the binder resin, a gallium phthalocyanine pigment, and a perinone compound in a solvent to prepare a coating liquid for the first layer, and then drying and / or curing the applied coating film. The second layer is obtained by dispersing a binder resin and / or a monomer for the binder resin, and a gallium phthalocyanine pigment in a solvent to prepare a coating liquid for the second layer, and then drying and / or curing the applied coating film.

[0066] The coating liquid may be prepared by adding only the gallium phthalocyanine and the perinone compound to a solvent and dispersing the mixture, followed by adding the binder resin and / or a monomer for the binder resin, or by adding the gallium phthalocyanine, the perinone compound, and the binder resin and / or a monomer for the binder resin together to a solvent and dispersing the mixture.

[0067] For the dispersion, a media type disperser such as a sand mill or a ball mill, or a liquid collision type disperser or an ultrasonic disperser can be used.

[0068] Examples of binder resins used in the first and second layers include resins (insulating resins) such as polyvinyl butyral resins, polyvinyl acetal resins, polyarylate resins, polycarbonate resins, polyester resins, polyvinyl acetate resins, polysulfone resins, polystyrene resins, phenoxy resins, acrylic resins, phenoxy resins, polyacrylamide resins, polyvinylpyridine resins, urethane resins, agarose resins, cellulose resins, casein resins, polyvinyl alcohol resins, polyvinylpyrrolidone resins, vinylidene chloride resins, acrylonitrile copolymers, and polyvinyl benzal resins. Organic photoconductive polymers such as poly-N-vinylcarbazole, polyvinylanthracene, and polyvinylpyrene can also be used. The binder resins may be used alone, or two or more may be used in combination as a mixture or copolymer. The resin may also be obtained as a cured film by polymerizing a composition containing a monomer having a polymerizable functional group in a coating solution to form a coating film (curing by polymerization of the monomer). The binder resin-like monomer has a polymerizable functional group, and examples of the polymerizable functional group include an isocyanate group, a blocked isocyanate group, a methylol group, an alkylated methylol group, an epoxy group, a metal alkoxide group, a hydroxyl group, an amino group, a carboxyl group, a thiol group, a carboxylic anhydride group, and a carbon-carbon double bond group.

[0069] The binder resins for the first and second layers may be the same, but from the viewpoints of adhesion to the charge transport layer and prevention of elution of the charge generating material into the charge transport layer, it is preferable to select different resins.

[0070] Examples of solvents used in the coating liquid include toluene, xylene, tetralin, chlorobenzene, dichloromethane, chloroform, trichloroethylene, tetrachloroethylene, carbon tetrachloride, methyl acetate, ethyl acetate, propyl acetate, methyl formate, ethyl formate, acetone, methyl ethyl ketone, cyclohexanone, diethyl ether, dipropyl ether, propylene glycol monomethyl ether, dioxane, methylal, tetrahydrofuran, water, methanol, ethanol, n-propanol, isopropanol, butanol, methyl cellosolve, methoxypropanol, dimethylformamide, dimethylacetamide, dimethyl sulfoxide, etc. Furthermore, the solvents can be used alone or in combination of one or more kinds.

[0071] <Charge transport layer> The charge transport layer is obtained by preparing a coating liquid for the charge transport layer by dissolving or dispersing a charge transport material and, if necessary, a binder resin in a solvent, and forming a coating film of the coating liquid for the charge transport layer and drying it.

[0072] Examples of charge transport materials include triarylamine compounds, hydrazone compounds, stilbene compounds, pyrazoline compounds, oxazole compounds, thiazole compounds, and triarylmethane compounds. Polymers having groups derived from these compounds in the main chain or side chain are also included. Among these, triarylamine compounds, styryl compounds, and benzidine compounds are preferred as charge transport materials, with triarylamine compounds being particularly preferred. The charge transport materials can be used singly or in combination of one or more.

[0073] Examples of binder resins used in the charge transport layer include resins (insulating resins) such as polyvinyl butyral resins, polyvinyl acetal resins, polyarylate resins, polycarbonate resins, polyester resins, polyvinyl acetate resins, polysulfone resins, polystyrene resins, phenoxy resins, polyvinyl acetate resins, acrylic resins, phenoxy resins, polyacrylamide resins, polyamide resins, polyvinylpyridine resins, cellulose-based resins, urethane resins, epoxy resins, agarose resins, cellulose resins, casein resins, polyvinyl alcohol resins, polyvinylpyrrolidone resins, vinylidene chloride resins, acrylonitrile copolymers, and polyvinyl benzal resins. Organic photoconductive polymers such as poly-N-vinylcarbazole, polyvinyl anthracene, and polyvinylpyrene can also be used. Among these, polycarbonate resins and polyarylate resins are preferred. The binder resins may be used alone or in combination of two or more types as a mixture or copolymer. The copolymerization form may be any of a block copolymer, a random copolymer, an alternating copolymer, etc. Furthermore, the molecular weight of these copolymers is preferably in the range of 10,000 to 300,000 in weight average molecular weight (Mw).

[0074] The content of the charge transport material in the charge transport layer is preferably 20% by mass to 80% by mass, more preferably 30% by mass to 60% by mass, based on the total mass of the charge transport layer. The thickness of the charge transport layer is preferably 5 μm or more and 40 μm or less.

[0075] <Protective layer> A protective layer may be provided on the photosensitive layer as needed. The protective layer can be obtained by dissolving a resin in an organic solvent to prepare a coating solution for the protective layer, forming a coating film of the coating solution for the protective layer, and drying the coating film. The protective layer can also be formed by curing the coating film with heat, electron beams, ultraviolet rays, or the like.

[0076] Resins used in the protective layer include polyvinyl butyral resin, polyester resin, polycarbonate resin (such as polycarbonate Z resin and modified polycarbonate resin), nylon resin, polyimide resin, polyarylate resin, polyurethane resin, styrene-butadiene copolymer, styrene-acrylic acid copolymer, and styrene-acrylonitrile copolymer.

[0077] In order to provide the protective layer with charge transporting properties, the protective layer may be formed by curing a monomer having charge transporting properties using various polymerization reactions or crosslinking reactions. Specifically, it is preferable to form the protective layer by polymerizing or crosslinking a charge transporting compound having a chain-polymerizable functional group and curing the polymerized compound.

[0078] The protective layer may also contain conductive particles, ultraviolet absorbers, lubricating particles such as fluorine-containing resin particles, etc. The conductive particles are preferably metal oxide particles such as tin oxide particles. The thickness of the protective layer is preferably 0.05 μm or more and 20 μm or less.

[0079] The coating method for each layer may be a dip coating method (dipping method), a spray coating method, a spinner coating method, a bead coating method, a blade coating method, a beam coating method, etc. Among these, the dip coating method is preferred from the viewpoints of efficiency and productivity.

[0080] [Process cartridge and electrophotographic device] An example of the schematic configuration of an electrophotographic apparatus having a process cartridge equipped with an electrophotographic photosensitive member is shown in Figure 2. In Figure 2, reference numeral 1 denotes a cylindrical (drum-shaped) electrophotographic photosensitive member, which is driven to rotate around an axis 2 in the direction of the arrow at a predetermined peripheral speed (process speed).

[0081] During rotation, the surface of the electrophotographic photosensitive member 1 is charged to a predetermined positive or negative potential by a charging means 3. Next, exposure light 4 is irradiated onto the charged surface of the electrophotographic photosensitive member 1 from an exposure means (not shown), and an electrostatic latent image corresponding to the target image information is formed. The image exposure light 4 is light whose intensity is modulated in accordance with a time-series electric digital image signal of the target image information, output from an exposure means such as a slit exposure or laser beam scanning exposure.

[0082] The electrostatic latent image formed on the surface of the electrophotographic photosensitive member 1 is developed (normal development or reversal development) with toner contained in the developing means 5, and a toner image is formed on the surface of the electrophotographic photosensitive member 1. The toner image formed on the surface of the electrophotographic photosensitive member 1 is transferred to a transfer material 7 by a transfer means 6. At this time, a bias voltage of a polarity opposite to that of the charge held by the toner is applied to the transfer means 6 from a bias power supply (not shown). Furthermore, if the transfer material 7 is paper, the transfer material 7 is taken out from a paper feed unit (not shown) and fed between the electrophotographic photosensitive member 1 and the transfer means 6 in synchronization with the rotation of the electrophotographic photosensitive member 1.

[0083] The transfer material 7 onto which the toner image has been transferred from the electrophotographic photosensitive member 1 is separated from the surface of the electrophotographic photosensitive member 1, and then transported to a fixing means 8, where the toner image is fixed, and the transfer material is printed out of the electrophotographic device as an image-formed product (print, copy).

[0084] After the toner image is transferred to the transfer material 7, the surface of the electrophotographic photoreceptor 1 is cleaned by cleaning means 9 to remove any adhering matter such as toner (residual toner after transfer). With the recently developed cleanerless system, the residual toner after transfer can also be removed directly by a developing device or the like. Furthermore, the surface of the electrophotographic photoreceptor 1 is subjected to a charge removal process using pre-exposure light 10 from pre-exposure means (not shown), and is then used repeatedly for image formation. Note that if the charging means 3 is a contact charging means using a charging roller or the like, the pre-exposure means is not necessarily required.

[0085] In the present invention, a process cartridge is formed by housing a plurality of components among the components such as the electrophotographic photosensitive member 1, the charging means 3, the developing means 5, and the cleaning means 9 described above in a container and supporting them as a unit. This process cartridge can be configured to be detachably attached to the main body of the electrophotographic apparatus. For example, at least one selected from the charging means 3, the developing means 5, and the cleaning means 9 is supported as a unit together with the electrophotographic photosensitive member 1 to form a cartridge. A process cartridge 11 that is detachably attached to the main body of the electrophotographic apparatus can be formed by using guide means 12 such as a rail of the main body of the electrophotographic apparatus.

[0086] When the electrophotographic device is a copier or printer, the exposure light 4 may be reflected or transmitted light from an original document, or may be light emitted by scanning a laser beam, driving an LED array, or driving a liquid crystal shutter array in accordance with a signal obtained by reading the original document with a sensor and converting it into a signal.

[0087] The electrophotographic photoreceptor 1 of the present invention can be widely applied to electrophotographic application fields such as laser beam printers, CRT printers, LED printers, FAX machines, liquid crystal printers, and laser plate making. [Example]

[0088] The present invention will be described in more detail below with reference to specific examples. The term "parts" used below means "parts by mass." However, the present invention is not limited to these. The film thickness of each layer of the electrophotographic photoreceptor in the examples and comparative examples was determined by a method using an eddy current film thickness meter (Fischerscope, manufactured by Fisher Instruments), a method using a spectral interference film thickness meter (C-13027-11, manufactured by Hamamatsu Photonics), or a method of converting the mass per unit area into specific gravity.

[0089] [Example 1] [Photoreceptor creation example] (Support) A cylindrical aluminum cylinder (JIS-A3003, aluminum alloy, outer diameter 30 mm, length 357.5 mm, wall thickness 0.7 mm) was used as a support (conductive support). It was ultrasonically cleaned in a cleaning solution containing pure water and detergent (product name: Chemicol CT, manufactured by Tokiwa Chemical Co., Ltd.), and after the cleaning solution was rinsed off, it was further ultrasonically cleaned in pure water for degreasing, and this was used as a support.

[0090] (First layer) A solution was obtained by dissolving 23 parts of a butyral resin (trade name: BM-1, manufactured by Sekisui Chemical Co., Ltd.) as a polyol resin and 23 parts of a blocked isocyanate resin (trade name: TPA-B80E, 80% solution, manufactured by Asahi Kasei Corporation) in 110 parts of a solvent in which methyl ethyl ketone and 1-butanol were mixed in a ratio of 35:65. To the resulting mixture, 50 parts of a mixture of a perinone compound represented by formula (1-1) and a perinone compound represented by formula (2-1) in a 1:1 ratio and 5 parts of hydroxygallium phthalocyanine (referred to as HOGa-Pc in the table) crystals having peaks at Bragg angles (2θ±0.2°) of 7.5°, 9.9°, 12.5°, 16.3°, 18.6°, 25.1°, and 28.3° in CuKα characteristic X-ray diffraction were added, and glass beads with a diameter of 0.8 mm were added, followed by stirring for 5 hours with a paint shaker to obtain a coating solution for the first layer. The obtained coating solution was dip-coated onto the support to form a coating film, and the coating film was dried and cured at 160° C. for 35 minutes to form a first layer having a thickness of 15.2 μm.

[0091] (Second layer) Hydroxygallium phthalocyanine crystals with CuKα characteristic X-ray diffraction peaks at Bragg angles (2θ±0.2°) of 7.5°, 9.9°, 12.5°, 16.3°, 18.6°, 25.1°, and 28.3° were prepared. 10 parts of the hydroxygallium phthalocyanine crystals, 5 parts of polyvinyl butyral (product name: S-LEC BX-1, manufactured by Sekisui Chemical Co., Ltd.), and 250 parts of cyclohexanone were placed in a sand mill using 1 mm diameter glass beads and dispersed for 2 hours. Next, 250 parts of ethyl acetate was added to the mixture to prepare a coating solution for the second layer. This coating solution was dip-coated onto the first layer, and the resulting coating was dried at 95° C. for 10 minutes to form a second layer having a thickness of 0.17 μm.

[0092] (charge transport layer) Next, 8 parts of an amine compound (hole transport material) represented by the following structural formula (7), [ka] and 10 parts of a polyester resin (P1) having a weight average molecular weight (Mw) of 100,000 and having repeating structural units represented by the following formulas (8) and (9) in a molar ratio of 5 / 5: [ka] [ka] The charge transport layer coating solution was prepared by dissolving the compound in a mixed solvent of 40 parts of dimethoxymethane and 60 parts of chlorobenzene. This charge transport layer coating solution was dip coated onto the second layer, and the resulting coating was dried at 120° C. for 40 minutes to form a charge transport layer having a thickness of 15 μm.

[0093] [Photoreceptor evaluation] The electrophotographic photoreceptors prepared as described above were evaluated for graininess and potential fluctuation under normal temperature and humidity conditions (temperature 23° C., relative humidity 50%). The results are shown in Table 5.

[0094] (Evaluation of dark decay) In this evaluation example, an experimental device was prepared in which a charging roller, to which a DC voltage superimposed on an AC voltage was applied, was brought into contact with an electrophotographic photosensitive member as a charging means. The surface potential (Vd0.1) 0.1 seconds after charging and the surface potential (Vd1.0) 1.0 seconds after charging were measured when the roller was uniformly charged to -900 V. The ratio (Vdd) of Vd1.0 to Vd0.1 was used as the dark decay. The higher the Vdd value, the greater the dark decay suppression effect. The Vdd thus obtained was used to evaluate the device according to the following evaluation criteria A to C. It is to be noted that an evaluation result of B or higher can be considered to indicate that the effects of the present invention have been achieved. The evaluation results are shown in Table 5. A: Vdd is 0.90 or more B: Vdd is 0.85 or more and less than 0.90 C: Vdd is less than 0.85

[0095] (Evaluation of graininess) Granularity was evaluated at the same charging potential as that used for the dark decay evaluation. Under the same charging potential settings and conditions as those used for the dark decay evaluation, the development contrast relative to the charging potential was adjusted so that the output results for all examples would be halftone images of the same density, and analog output was performed without exposure. Five points within the output image were observed with an optical microscope, and halftone density unevenness was evaluated sensorily using the following criteria. Ranks A, B, C, and D represent levels where the effects of the invention are achieved in terms of graininess, with Rank A being judged to be an excellent level, while Rank E is a level where the effects of the invention are not achieved. A: No uneven half-tone density was observed at any of the five observation points. B: Slight unevenness in half-tone density is visible at some of the five observation points. C: Slight unevenness in half-tone density is visible at all five observation points. D: Halftone density unevenness is clearly visible at some of the five observation points, but is not noticeable. E: Half-tone density unevenness is clearly visible at all five observation points.

[0096] (Evaluation of potential fluctuations during repeated use) In this evaluation example, the electrophotographic photoreceptor was mounted in a multifunction printer, imageRUNNER ADVANCE C5255 (registered trademark), manufactured by Canon Inc., and evaluation was carried out. Specifically, the evaluation device was placed in an environment of normal temperature and humidity (23°C / 50%RH). The electrophotographic photosensitive member thus prepared was mounted in a process cartridge, which was then mounted in a cartridge station of a copying machine, and evaluation was carried out. The developing cartridge equipped with the electrophotographic photosensitive member was attached to the evaluation device, and the photosensitive member was repeatedly used by passing 10,000 sheets of paper. A single-color character image with a print rate of 1% was repeatedly formed on 10,000 sheets of A4-sized plain paper. The initial light area potential at this time was compared with the light area potential after 10,000 sheets of paper were repeatedly formed, and this was taken as the value of potential variation (ΔVl). After 10,000 sheets had been passed through, the cartridge was left to stand for 5 minutes, and the developing cartridge was then replaced with a potential measuring device to measure the light area potential (Vlb) and dark area potential (Vdb) after repeated use. The difference between the bright area potential after repeated use and the initial bright area potential was determined as the bright area potential fluctuation (ΔVl = |Vlb| - |Vla|), and the difference between the dark area potential after repeated use and the initial dark area potential was determined as the dark area potential fluctuation (ΔVd = |Vdb| - |Vda|), and these were evaluated according to the following evaluation ranks. In the present invention, ranks A, B, C, and D represent levels of potential fluctuation that are not problematic in actual use, and rank A was determined to be an excellent level. On the other hand, rank E was determined to be a level that would cause problems in actual use. A: When the change in light potential and dark potential is within 5V B: When the change in the light potential and dark potential is greater than 5V and less than 10V C: When the change in the light potential and dark potential is greater than 10V and less than 20V D: When the change in the light potential and dark potential is greater than 20V and less than 30V E: When the change in light potential and dark potential is greater than 30V

[0097] [Examples 2 to 12] A photoreceptor was prepared in the same manner as in Example 1, except that the first layer was prepared using the material composition shown in Table 1 and the second layer was prepared using the material composition shown in Table 2, and evaluation was performed in the same manner as in Example 1. The evaluation results are shown in Table 5.

[0098] [Example 13] A photoreceptor was prepared in the same manner as in Example 1, except that the hydroxygallium phthalocyanine pigment (referred to as HOGa-Pc in Tables 1 and 2) in the first and second layers was changed to a chlorogallium phthalocyanine pigment (referred to as ClGa-Pc in Tables 1 and 2) having a crystal form that has strong peaks at Bragg angles (2θ±0.2°) of 7.4°, 16.6°, 25.5°, and 28.2° in CuKα characteristic X-ray diffraction, and evaluations were performed in the same manner as in Example 1. The evaluation results are shown in Table 5.

[0099] [Example 14] A photoreceptor was prepared in the same manner as in Example 1, except that the hydroxygallium phthalocyanine pigment in the second layer was changed to a chlorogallium phthalocyanine pigment of a crystal form having strong peaks at Bragg angles (2θ±0.2°) of 7.4°, 16.6°, 25.5°, and 28.2° in CuKα characteristic X-ray diffraction, and evaluations were performed in the same manner as in Example 1. The evaluation results are shown in Table 5.

[0100] [Example 15] A photoreceptor was prepared in the same manner as in Example 1, except that the perinone compound in the first layer was changed to a mixture of the perinone compound represented by formula (1-8) and the perinone compound represented by formula (2-8) in a 1:1 ratio, and evaluation was performed in the same manner as in Example 1. The evaluation results are shown in Table 5.

[0101] [Example 16] A photoreceptor was prepared in the same manner as in Example 1, except that the perinone compound in the first layer was changed to a 1:1 mixture of the perinone compound represented by formula (1-12) and the perinone compound represented by formula (2-12), and evaluation was performed in the same manner as in Example 1. The evaluation results are shown in Table 5.

[0102] [Example 17] A photoreceptor was prepared in the same manner as in Example 1, except that the perinone compound in the first layer was changed to a 1:1 mixture of the perinone compound represented by formula (1-13) and the perinone compound represented by formula (2-13), and evaluation was performed in the same manner as in Example 1. The evaluation results are shown in Table 5.

[0103] [Example 18] A photoreceptor was produced and evaluated in the same manner as in Example 1, except that the structure of the first layer in Example 1 was changed as follows.

[0104] (First layer) A 1:1 mixture of 50 parts of a perinone compound represented by formula (1-1) and a perinone compound represented by formula (2-1), 45 parts of polyvinyl butyral (product name: S-LEC BX-1, manufactured by Sekisui Chemical Co., Ltd.), 5 parts of hydroxygallium phthalocyanine crystals having peaks at Bragg angles (2θ±0.2°) of 7.5°, 9.9°, 12.5°, 16.3°, 18.6°, 25.1°, and 28.3° in CuKα characteristic X-ray diffraction, and 150 parts of cyclohexanone were mixed with 0.8 mm diameter glass beads and stirred for 4 hours using a paint shaker. Next, 150 parts of ethyl acetate was added to the mixture to prepare a coating solution for a first layer. The coating solution was dip-coated onto a support, and the resulting coating was dried for 20 minutes at 95° C. to form a first layer having a thickness of 5.2 μm. The evaluation results are shown in Table 5.

[0105] [Example 19] A photoreceptor was produced and evaluated in the same manner as in Example 1, except that the structure of the first layer in Example 1 was changed as follows.

[0106] (First layer) 50 parts of a 1:1 mixture of the perinone compound represented by formula (1-1) and the perinone compound represented by formula (2-1), 50 parts of a copolymer nylon resin (trade name: Amilan CM8000, manufactured by Toray Industries, Inc.), and 5 parts of hydroxygallium phthalocyanine crystals having peaks at Bragg angles (2θ±0.2°) of 7.5°, 9.9°, 12.5°, 16.3°, 18.6°, 25.1°, and 28.3° in CuKα characteristic X-ray diffraction were dispersed in a mixture of 330 parts of methanol and 170 parts of butanol, and glass beads with a diameter of 0.8 mm were added to the dispersion and stirred for 4 hours using a paint shaker to prepare a coating solution for a first layer. The coating solution was applied to the support by dip coating, and the resulting coating film was heated at 100° C. for 20 minutes to form a first layer having a film thickness of 5.0 μm. The evaluation results are shown in Table 5.

[0107] [Table 1]

[0108] [Table 2]

[0109] [Comparative Example 1] A photoreceptor was prepared and evaluated in the same manner as in Example 1, except that the first layer was prepared using the material composition shown in Table 3 and the second layer was prepared using the material composition shown in Table 4. The evaluation results are shown in Table 5.

[0110] [Table 3]

[0111] [Table 4]

[0112] [Table 5]

[0113] Comparative Example 2 A photoreceptor was prepared and evaluated in the same manner as in Comparative Example 1, except that the perinone compound in the first layer was changed to the perylene pigment represented by formula (10) and the material composition was changed to the composition shown in Table 3. The evaluation results are shown in Table 5. [ka]

[0114] Comparative Example 3 A photoreceptor was prepared and evaluated in the same manner as in Comparative Example 1, except that the perinone compound in the first layer was changed to the anthanthrone pigment represented by formula (11) and the material composition was changed to the composition shown in Table 3. The evaluation results are shown in Table 5. [ka]

[0115] Comparative Example 4 A photoreceptor was prepared and evaluated in the same manner as in Example 1, except that the hydroxygallium phthalocyanine pigment in the first and second layers was changed to an oxytitanium phthalocyanine pigment (referred to as TiO-Pc in Tables 3 and 4) of a crystal form that has strong peaks at Bragg angles (2θ±0.2°) of 9.0°, 14.2°, 23.9°, and 27.1° in CuKα characteristic X-ray diffraction. The evaluation results are shown in Table 5.

[0116] Comparative Example 5 A photoreceptor was prepared and evaluated in the same manner as in Comparative Example 4, except that the perinone compound in the first layer was changed to the perylene pigment represented by formula (10). The evaluation results are shown in Table 5.

[0117] Comparative Example 6 A photoreceptor was prepared and evaluated in the same manner as in Comparative Example 4, except that the perinone compound in the first layer was changed to the anthanthrone pigment represented by formula (11). The evaluation results are shown in Table 5.

[0118] Comparative Example 7 A photoreceptor was prepared and evaluated in the same manner as in Example 1, except that the structures of the first layer and the second layer in Example 1 were changed as follows. The evaluation results are shown in Table 5.

[0119] (First layer) 50 parts of the perylene pigment represented by formula (11), 50 parts of copolymer nylon resin (trade name: Amilan CM8000, manufactured by Toray Industries, Inc.), 330 parts of methanol, and 170 parts of butanol were dispersed in a mixture, and glass beads having a diameter of 0.8 mm were added to the mixture, followed by stirring for 4 hours with a paint shaker, to prepare a coating solution for a first layer. This coating solution was dip-coated onto a support, and the resulting coating film was heated at 100° C. for 20 minutes to form a first layer having a film thickness of 5.4 μm.

[0120] (Second layer) A second layer coating solution was prepared by adding 10 parts of a crystalline oxytitanium phthalocyanine pigment having strong peaks at Bragg angles (2θ±0.2°) of 9.0°, 14.2°, 23.9°, and 27.1° in CuKα characteristic X-ray diffraction, 5 parts of polyvinyl butyral (product name: S-LEC BX-1, manufactured by Sekisui Chemical Co., Ltd.), and 250 parts of cyclohexanone, along with 0.8 mm diameter glass beads, and stirring the mixture for 4 hours using a paint shaker. 250 parts of ethyl acetate was then added to the mixture. This coating solution was dip-coated onto the first layer, and the resulting coating was dried at 95° C. for 10 minutes to form a second layer having a thickness of 0.29 μm.

[0121] The disclosure of this embodiment includes the following configurations and methods. [Configuration 1] An electrophotographic photoreceptor having a support, a first layer, a second layer, and a charge transport layer in this order, The first layer contains a binder resin, a gallium phthalocyanine pigment, and at least one perinone compound selected from the group consisting of perinone compounds represented by the following formula (1) and perinone compounds represented by the following formula (2): The second layer contains a binder resin and a gallium phthalocyanine pigment. [ka] [ka] (In formula (1), R 11 ~R 18 and in formula (2), R 21 ~R 28 R each independently represents a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted aryloxy group, or a substituted or unsubstituted alkoxycarbonyl group. 11 ~R 14 , R 15 ~R 18 , R 21 ~R 24 and R 25 ~R 28 Adjacent groups in each group may be linked together to form a ring. [Configuration 2] the content of the perinone compound in the first layer is 50% by mass or more and 1000% by mass or less with respect to the content of the gallium phthalocyanine pigment in the first layer, the second layer does not contain the perinone compound, or the second layer contains the perinone compound, and the content of the perinone compound in the second layer is 1% by mass or less relative to the content of the gallium phthalocyanine pigment in the second layer; 2. The electrophotographic photoreceptor according to claim 1. [Configuration 3] the content of the gallium phthalocyanine pigment in the first layer is 5% by mass or more and 50% by mass or less with respect to the total mass of the first layer, the content of the gallium phthalocyanine pigment in the second layer is 50% by mass or more and 75% by mass or less with respect to the total mass of the second layer; 3. The electrophotographic photoreceptor according to claim 1. [Configuration 4] 4. The electrophotographic photoreceptor according to any one of configurations 1 to 3, wherein the thickness of the first layer is from 2 μm to 20 μm, and the thickness of the second layer is from 0.1 μm to 0.5 μm. [Configuration 5] The gallium phthalocyanine pigment is a chlorogallium phthalocyanine pigment and 5. The electrophotographic photoreceptor according to any one of configurations 1 to 4, wherein the pigment is at least one selected from the group consisting of hydroxygallium phthalocyanine pigments. [Configuration 6] The electrophotographic photoreceptor according to any one of Configurations 1 to 5, wherein the first layer contains, as the perinone compound, at least one compound represented by formula (3) below selected from the group consisting of perinone compounds represented by formula (4) below: [ka] [ka] (In formula (3), R 31 and R 32 , and R in formula (4) 41 and R 42 each independently represents a branched alkyl group having 3 to 10 carbon atoms. [Configuration 7] The electrophotographic photoreceptor according to any one of Configurations 1 to 6, wherein the first layer contains, as the perinone compound, at least one compound represented by the formula (5) below selected from the group consisting of perinone compounds represented by the formula (6) below: [ka] [ka] (R in Equation (5) 51 ~R 56 , and R in formula (6) 61 ~R 66 each independently represents a methyl group, an ethyl group, or a propyl group. [Configuration 8] the first layer contains the perinone compound and the gallium phthalocyanine pigment It is a layer formed by drying and / or curing a coating film of a coating liquid containing The electrophotographic photoreceptor according to any one of the first to seventh configurations. [Configuration 9] A process cartridge integrally supporting the electrophotographic photosensitive member according to any one of configurations 1 to 8 and at least one means selected from the group consisting of a charging means, a developing means, and a cleaning means, and being detachably mountable to the main body of an electrophotographic apparatus. [Configuration 10] An electrophotographic apparatus comprising the electrophotographic photosensitive member according to any one of Configurations 1 to 8, a charging unit, an exposure unit, a developing unit, and a transfer unit. [Method 1] A method for producing an electrophotographic photoreceptor having a support, a first layer, a second layer, and a charge transport layer in this order, comprising: The manufacturing method comprises: a step of preparing a coating liquid for a first layer, the coating liquid containing a binder resin and / or a monomer for the binder resin, a gallium phthalocyanine pigment, and at least one perinone compound selected from the group consisting of a compound represented by the following formula (1) and a compound represented by the following formula (2); forming a coating film of the coating liquid for the first layer on the support, and drying and / or curing the coating film of the coating liquid for the first layer to form the first layer on the support; a step of preparing a coating liquid for a second layer containing a binder resin and / or a monomer for the binder resin, and a gallium phthalocyanine pigment; forming a coating film of the second layer coating liquid on the first layer, and drying and / or curing the coating film of the second layer coating liquid to form the second layer on the first layer; and forming the charge transport layer on the second layer; 1. A method for producing an electrophotographic photoreceptor, comprising: [ka] [ka] (In formula (1), R 11 ~R 18 , and in equation (2), R 21 ~R 28 R each independently represents a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted aryloxy group, or a substituted or unsubstituted alkoxycarbonyl group. 11 ~R 14 , R 15 ~R 18 , R 21 ~R 24 and R 25 ~R 28 Adjacent groups in each group may be linked together to form a ring. [Explanation of symbols]

[0122] 101:Support 102: Undercoat layer 103: First layer 104: Second Layer 105: Charge transport layer 1: Electrophotographic photoreceptor 2: Axis 3: Charging means 4: Image exposure light 5: Developing method 6: Transfer means 7: Transfer material 8: Image fixing means 9: Cleaning means 10: Pre-exposure light 11: Process cartridge 12: Guidance means

Claims

1. An electrophotographic photoreceptor having a support, a first layer, a second layer, and a charge transport layer in this order, The first layer contains a binder resin, a gallium phthalocyanine pigment, and at least one perinone compound selected from the group consisting of perinone compounds represented by the following formula (1) and perinone compounds represented by the following formula (2): the second layer contains a binder resin and a gallium phthalocyanine pigment; An electrophotographic photoreceptor characterized by: 【Chemistry 1】 【Chemistry 2】 (In formula (1), R １１ ~R １８ and in formula (2), R ２１ ~R ２８ R each independently represents a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted aryloxy group, or a substituted or unsubstituted alkoxycarbonyl group. １１ ~R １４ , R １５ ~R １８ , R ２１ ~R ２４ and R ２５ ~R ２８ Adjacent groups in each group may be linked together to form a ring.

2. the content of the perinone compound in the first layer is 50% by mass or more and 1000% by mass or less with respect to the content of the gallium phthalocyanine pigment in the first layer, the second layer does not contain the perinone compound, or the second layer contains the perinone compound, and the content of the perinone compound in the second layer is 1 mass % or less relative to the content of the gallium phthalocyanine pigment in the second layer; The electrophotographic photoreceptor according to claim 1 .

3. a content of the gallium phthalocyanine pigment in the first layer is 5% by mass or more and 50% by mass or less with respect to the total mass of the first layer, the content of the gallium phthalocyanine pigment in the second layer is 50% by mass or more and 75% by mass or less with respect to the total mass of the second layer; The electrophotographic photoreceptor according to claim 1 .

4. the thickness of the first layer is 2 μm or more and 20 μm or less, The thickness of the second layer is 0.1 μm or more and 0.5 μm or less. The electrophotographic photoreceptor according to claim 1 .

5. 2. The electrophotographic photoreceptor according to claim 1, wherein the gallium phthalocyanine pigment is at least one selected from the group consisting of chlorogallium phthalocyanine pigments and hydroxygallium phthalocyanine pigments.

6. 2. The electrophotographic photoreceptor according to claim 1, wherein the first layer contains, as the perinone compound, at least one compound represented by a perinone compound selected from the group consisting of perinone compounds represented by the following formula (3) and perinone compounds represented by the following formula (4): 【Transformation 3】 【Chemistry 4】 (In formula (3), R ３１ and R ３２ , and R in formula (4) ４１ and R ４２ each independently represents a branched alkyl group having 3 to 10 carbon atoms.

7. 2. The electrophotographic photoreceptor according to claim 1, wherein the first layer contains, as the perinone compound, at least one compound selected from the group consisting of perinone compounds represented by the following formula (5) and perinone compounds represented by the following formula (6): 【Transformation 5】 【Transformation 6】 (R in formula (5) ５１ ~R ５６ , and R in formula (6) ６１ ~R ６６ each independently represents a methyl group, an ethyl group, or a propyl group.

8. 2. The electrophotographic photoreceptor according to claim 1, wherein the first layer is a layer formed by drying and / or curing a coating film of a coating liquid containing the perinone compound and the gallium phthalocyanine pigment.

9. 9. A process cartridge that integrally supports the electrophotographic photosensitive member according to claim 1 and at least one means selected from the group consisting of a charging means, a developing means, and a cleaning means, and is detachably mountable to a main body of an electrophotographic apparatus.

10. 9. An electrophotographic apparatus comprising the electrophotographic photoreceptor according to claim 1, a charging unit, an exposure unit, a developing unit, and a transfer unit.

11. A method for producing an electrophotographic photoreceptor having a support, a first layer, a second layer, and a charge transport layer in this order, comprising: The manufacturing method comprises: a step of preparing a coating liquid for a first layer, the coating liquid containing a binder resin and / or a monomer for the binder resin, a gallium phthalocyanine pigment, and at least one perinone compound selected from the group consisting of a compound represented by the following formula (1) and a compound represented by the following formula (2); forming a coating film of the coating liquid for the first layer on the support, and drying and / or curing the coating film of the coating liquid for the first layer to form the first layer on the support; a step of preparing a coating liquid for a second layer containing a binder resin and / or a monomer for the binder resin, and a gallium phthalocyanine pigment; forming a coating film of the second layer coating liquid on the first layer, and drying and / or curing the coating film of the second layer coating liquid to form the second layer on the first layer; and forming the charge transport layer on the second layer; 1. A method for producing an electrophotographic photoreceptor, comprising: 【Transformation 7】 【Transformation 8】 (In formula (1), R １１ ~R １８ , and in formula (2), R ２１ ~R ２８ R each independently represents a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted aryloxy group, or a substituted or unsubstituted alkoxycarbonyl group. １１ ~R １４ , R １５ ~R １８ , R ２１ ~R ２４ and R ２５ ~R ２８ Adjacent groups in each group may be linked together to form a ring.

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