Electrophotographic photoreceptor, process cartridge and electrophotographic image forming apparatus

Abstract

To provide an electrophotographic photoreceptor that can prevent an environmental variation of electrical characteristics.SOLUTION: A surface layer of an electrophotographic photoreceptor contains a compound having a specific structure.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to an electrophotographic photosensitive member, and a process cartridge and an electrophotographic image forming apparatus each having the electrophotographic photosensitive member. [Background technology]

[0002] Extensive research has been conducted on electrophotographic photoreceptors mounted in electrophotographic image forming apparatuses (hereinafter also referred to as "electrophotographic apparatuses"), particularly organic electrophotographic photoreceptors containing an organic photoconductive substance as a charge generating substance (hereinafter, "electrophotographic photoreceptor" refers to organic electrophotographic photoreceptors). In recent years, with the increase in printing speed, there has been a demand for electrophotographic photoreceptors with a longer life. Patent Documents 1 and 2 describe electrophotographic photoreceptors having a surface layer that exhibits excellent mechanical strength. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 10-268535 [Patent Document 2] Japanese Patent Application Laid-Open No. 2000-66425 Summary of the Invention [Problem to be solved by the invention]

[0004] As a result of intensive studies by the present inventors, it was found that the electrophotographic photoreceptors described in Patent Documents 1 and 2 have large differences in electrical properties caused by differences in usage environment. In particular, the difference (environmental fluctuation) between a high-temperature, high-humidity environment and a low-temperature, low-humidity environment is significant. If the environmental fluctuation is large, image density changes when the usage environment changes, so there is a demand for electrophotographic photoreceptors in which environmental fluctuation is suppressed.

[0005] Therefore, an object of the present invention is to provide an electrophotographic photoreceptor in which differences in electrical characteristics caused by differences in the use environment (environmental fluctuations) are suppressed, and further to provide a process cartridge and an electrophotographic apparatus having the electrophotographic photoreceptor. [Means for solving the problem]

[0006] The above object can be achieved by the present invention, which comprises: The electrophotographic photoreceptor has a support and a surface layer, and is characterized in that the surface layer contains a compound represented by the following formula (1). [ka] (In formula (1), R 11 ~R 13 each independently represents an alkylene group having 1 to 6 carbon atoms. 11 ~Q 13 each independently represents a hydroxy group or a carboxy group.

[0007] The process cartridge according to the present invention is characterized in that it integrally supports the electrophotographic photosensitive member and at least one means selected from the group consisting of a charging means, a developing means, a transfer means, and a cleaning means, and is detachably mountable to the main body of the electrophotographic apparatus.

[0008] An electrophotographic apparatus according to the present invention is characterized by comprising the above electrophotographic photosensitive member, as well as a charging means, an exposing means, a developing means and a transferring means. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide an electrophotographic photoreceptor capable of suppressing differences in electrical characteristics caused by differences in the use environment (environmental fluctuations), and further to provide a process cartridge and an electrophotographic apparatus having the electrophotographic photoreceptor. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a diagram showing an example of a schematic configuration of an electrophotographic apparatus equipped with a process cartridge having an electrophotographic photosensitive member of the present invention. [Figure 2] FIG. 2 is a diagram illustrating an example of a layer structure of the electrophotographic photoreceptor of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0011] The present invention will be described in detail below with reference to preferred embodiments. The electrophotographic photoreceptor according to one aspect of the present invention is characterized in that the surface layer contains a compound represented by the following formula (1). [ka] (In formula (1), R 11 ~R 13 each independently represents an alkylene group having 1 to 6 carbon atoms. 11 ~Q 13 each independently represents a hydroxy group or a carboxy group.

[0012] The present inventors speculate that the reason why the effects of the present invention are achieved by having the above characteristics is as follows. It is speculated that the difference in the electrical properties of electrophotographic photoreceptors caused by differences in the usage environment (environmental fluctuations) is due to the fact that the effect of moisture that penetrates the surface layer and reaches the lower layer on the charge-generating material in the photosensitive layer differs depending on the usage environment. In particular, it is speculated that the absolute moisture content in the usage environment differs greatly between high-temperature, high-humidity environments and low-temperature, low-humidity environments, which means that there is a difference in the effect that moisture has on the charge-generating material, resulting in greater environmental fluctuations.

[0013] The electrophotographic photoreceptor of the present invention contains a compound represented by the following formula (1) in the surface layer. [ka] (In formula (1), R 11 ~R 13each independently represents an alkylene group having 1 to 6 carbon atoms. 11 ~Q 13 each independently represents a hydroxy group or a carboxy group.

[0014] The compound represented by formula (1) has a hydroxy group or a carboxy group. Because the hydroxy group or the carboxy group is highly hydrophilic, moisture that has penetrated into the surface layer is easily attracted to the compound represented by formula (1). In addition, the compound represented by formula (1) has an isocyanuric ring skeleton. Because the isocyanuric ring skeleton has high polarity, it easily forms hydrogen bonds with water molecules. The inventors of the present application speculate that the synergistic effect of the hydroxy group or the carboxy group and the isocyanuric ring skeleton can prevent moisture that has penetrated into the surface layer from reaching the lower layer, thereby suppressing environmental changes.

[0015] Specific examples of the compound represented by the formula (1) are listed below (exemplary compounds 1-1 to 1-10), but the present invention is not limited to these. [ka]

[0016] The content of the compound represented by formula (1) in the surface layer is preferably 0.01% by mass to 1% by mass relative to the total mass of the surface layer. This range is believed to achieve an appropriate balance between the ease of moisture penetration into the surface layer and the difficulty of moisture reaching the lower layer, thereby suppressing environmental changes. More preferably, the content of the compound represented by formula (1) in the surface layer is 0.01% by mass to 0.5% by mass relative to the total mass of the surface layer.

[0017] Q in the compound represented by formula (1) 11 ~Q 13 is more preferably a hydroxy group. In this case, the inventors of the present application speculate that an appropriate balance can be achieved between the ease of penetration of moisture into the surface layer and the difficulty of moisture reaching the lower layer, thereby suppressing environmental changes.

[0018] R of the compound represented by formula (1) 11 ~R 13 is preferably an alkylene group having 1 or 2 carbon atoms. The inventors of the present application speculate that this reduces steric hindrance and facilitates the formation of hydrogen bonds between water molecules and the isocyanuric ring skeleton, thereby suppressing environmental fluctuations.

[0019] The surface layer preferably further contains a polymer of a composition containing a compound having a chain-polymerizable functional group. In this case, the inventors of the present application speculate that the crosslinked structure of the polymer can prevent moisture from reaching the lower layer, thereby suppressing environmental changes.

[0020] The composition preferably contains a compound represented by the following formula (2): [ka] (In the above formula (2), R 21 ~R 23 each independently represents an alkylene group having 1 to 6 carbon atoms. 21 ~Q 23 each independently represents an acryloyloxy group or a methacryloyloxy group. In this case, it is presumed that the compound represented by the formula (1) is more easily dispersed uniformly in the surface layer, preventing moisture from reaching the lower layer, thereby suppressing environmental fluctuations.

[0021] Specific examples of the compound represented by the formula (2) are listed below (exemplary compounds 2-1 to 2-6), but the present invention is not limited to these. [ka]

[0022] The composition preferably contains a compound represented by the following formula (CT-1) or (CT-2).

[0023] [ka] (In the above formula (CT-1), Ar 11 ~Ar 13 are each independently a substituted aryl group or an unsubstituted aryl group. The substituent that the substituted aryl group may have is an alkyl group having 1 to 6 carbon atoms or a monovalent functional group represented by any one of the following formulae (P-1) to (P-3). However, the compound represented by the above formula (CT-1) has at least one monovalent functional group represented by any one of the following formulae (P-1) to (P-3).

[0024] [ka] (In the above formula (P-1), Z 11 represents a single bond or an alkylene group having 1 to 6 carbon atoms. 11 represents a hydrogen atom or a methyl group.

[0025] [ka] (In the above formula (P-2), Z 21 represents a single bond or an alkylene group having 1 to 6 carbon atoms.

[0026] [ka] (In the above formula (P-3), Z 31 represents a single bond or an alkylene group having 1 to 6 carbon atoms.

[0027] [ka] (In the above formula (CT-2), Ar 21 ~Ar 24 each independently represents a substituted aryl group or an unsubstituted aryl group. 25represents a substituted arylene group or an unsubstituted arylene group. The substituent that the substituted aryl group may have is an alkyl group having 1 to 6 carbon atoms or a monovalent functional group represented by the following formulas (P-1) to (P-3). The substituent that the substituted arylene group may have is an alkyl group having 1 to 6 carbon atoms or a monovalent functional group represented by the following formulas (P-1) to (P-3). However, the compound represented by the above formula (CT-2) has at least one monovalent functional group represented by any of the following formulas (P-1) to (P-3).

[0028] [ka] (In the above formula (P-1), Z 11 represents a single bond or an alkylene group having 1 to 6 carbon atoms. 11 represents a hydrogen atom or a methyl group.

[0029] [ka] (In the above formula (P-2), Z 21 represents a single bond or an alkylene group having 1 to 6 carbon atoms.

[0030] [ka] (In the above formula (P-3), Z 31 represents a single bond or an alkylene group having 1 to 6 carbon atoms.

[0031] The compound represented by formula (CT-1) or (CT-2) has a triarylamine skeleton, which is generally considered to have hole transport ability. When the composition contains the compound represented by formula (CT-1) or (CT-2), the triarylamine skeleton is uniformly dispersed in the surface layer, resulting in good electrical properties.

[0032] In formula (CT-1), the substituted aryl group or the unsubstituted aryl group is preferably any one of a substituted phenyl group or an unsubstituted phenyl group, a substituted biphenylyl group or an unsubstituted biphenylyl group, and a substituted fluorenyl group or an unsubstituted fluorenyl group.

[0033] In formula (CT-2), the substituted arylene group or the unsubstituted arylene group is preferably any one of a substituted phenylene group or an unsubstituted phenylene group, a substituted biphenylylene group or an unsubstituted biphenylylene group, and a substituted fluorenylene group or an unsubstituted fluorenylene group.

[0034] In the formulas (P-1) to (P-3), the alkylene group having 1 to 6 carbon atoms is preferably an ethylene group, a 1,3-propylene group, a 1,2-propylene group, or a 1,4-butylene group.

[0035] Specific examples of the compound represented by the formula (CT-1) (exemplary compounds CT1-1 to CT1-11) and specific examples of the compound represented by the formula (CT-2) (exemplary compounds CT2-1 to CT2-4) are listed below, but the present invention is not limited thereto.

[0036] [ka]

[0037] [ka]

[0038] When the surface layer contains a polymer of a composition containing a compound represented by formula (CT-1) or (CT-2), the content of the compound represented by formula (CT-1) or (CT-2) is preferably 30 mass% or more relative to the total mass of the composition. When the surface layer contains a polymer of the compound represented by formula (CT-1) or (CT-2), the content of the compound represented by formula (1) in the surface layer is preferably 0.015% by mass to 1% by mass relative to the content calculated before polymerization. This range ensures good electrical properties. The composition may also contain the compound represented by formula (1). In this case, the content of the compound represented by formula (1) in the composition is preferably 0.015% by mass to 1% by mass relative to the content of the compound represented by formula (CT-1) or (CT-2) in the composition.

[0039] Next, the configuration of the electrophotographic photoreceptor of the present invention will be described, along with the respective components of the electrophotographic photoreceptor and the method for producing the same.

[0040] [Electrophotographic photoreceptor] The electrophotographic photoreceptor according to one aspect of the present invention is characterized by having a support and a surface layer.

[0041] Fig. 2 is a diagram showing an example of the layer structure of an electrophotographic photoreceptor. In Fig. 2, the electrophotographic photoreceptor has a support 21, an undercoat layer 22, a charge generation layer 23, a charge transport layer 24, and a protective layer 25. In this case, the charge generation layer 23 and the charge transport layer 24 constitute the photosensitive layer.

[0042] As a method for producing an electrophotographic photoreceptor, a method of preparing a coating liquid for each layer described later, coating the layers in the desired order, and drying the liquid can be mentioned. The coating method in this case can be immersion coating, spray coating, inkjet coating, roll coating, die coating, blade coating, curtain coating, wire bar coating, ring coating, etc. Among these, immersion coating is preferred from the viewpoint of efficiency and productivity.

[0043] The support and each layer will be described below. <Support> The electrophotographic photoreceptor of the present invention has a support, and the support preferably has electrical conductivity. The support may be in the form of a cylinder, a belt, a sheet, or the like. Of these, a cylindrical support is preferred. The surface of the support may be subjected to electrochemical treatment such as anodization, blasting, cutting, or the like.

[0044] The support is preferably made of a metal, a resin, or a glass. Examples of metals include aluminum, iron, nickel, copper, gold, stainless steel, and alloys thereof, among which an aluminum support using aluminum is preferred.

[0045] It is also preferable to impart electrical conductivity to the resin or glass by processing such as mixing or coating with an electrically conductive material.

[0046] <Conductive layer> In the present invention, a conductive layer may be provided on the support. By providing a conductive layer, scratches and irregularities on the support surface can be concealed and light reflection on the support surface can be controlled. The conductive layer preferably contains conductive particles and a resin.

[0047] Examples of materials for 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, magnesium oxide, antimony oxide, bismuth oxide, etc. Examples of metals include aluminum, nickel, iron, nichrome, copper, zinc, silver, etc. Among these, it is preferable to use metal oxides as the conductive particles, and it is particularly preferable to use titanium oxide, tin oxide, or zinc oxide. When metal oxides are used as the conductive particles, the surface of the metal oxides may be treated with a silane coupling agent or the like, or the metal oxides may be doped with elements such as phosphorus or aluminum or oxides thereof. The conductive particles may have a layered structure including a core particle and a coating layer covering the core particle. Examples of the core particle include titanium oxide, barium sulfate, and zinc oxide. Examples of the coating layer include a metal oxide such as tin oxide. When metal oxide is used as the conductive particles, the volume average particle size is preferably 1 nm to 500 nm, and more preferably 3 nm to 400 nm.

[0048] 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. The conductive layer may further contain silicone oil, resin particles, a masking agent such as titanium oxide, and the like.

[0049] The average thickness of the conductive layer is preferably 1 μm to 50 μm, and particularly preferably 3 μm to 40 μm.

[0050] The conductive layer can be formed by preparing a coating solution for the conductive layer containing the above materials and solvent, forming a coating film from this, and drying it. Examples of solvents used in the coating solution include alcohol-based solvents, sulfoxide-based solvents, ketone-based solvents, ether-based solvents, ester-based solvents, and aromatic hydrocarbon-based solvents. Examples of dispersion methods for dispersing the conductive particles in the coating solution for the conductive layer include methods using a paint shaker, sand mill, ball mill, or liquid collision-type high-speed disperser.

[0051] <Undercoat layer> In the present invention, an undercoat layer may be provided on the support or the conductive layer. By providing an undercoat layer, the adhesion between layers can be improved and a charge injection blocking function can be imparted.

[0052] The undercoat layer preferably contains a resin. Alternatively, the undercoat layer may be formed as a cured film by polymerizing a composition containing a monomer having a polymerizable functional group.

[0053] 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.

[0054] Examples of the polymerizable functional group contained in 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 group containing a carboxylic acid anhydride structure, and a group containing a carbon-carbon double bond.

[0055] Furthermore, for the purpose of improving electrical properties, the undercoat layer may further contain an electron transporting substance, a metal oxide, a metal, a conductive polymer, etc. Among these, it is preferable to use an electron transporting substance 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 a monomer having the polymerizable functional group. Examples of metal oxides include indium tin oxide, tin oxide, indium oxide, titanium oxide, zinc oxide, aluminum oxide, silicon dioxide, etc. Examples of metals include gold, silver, aluminum, etc. The undercoat layer may further contain additives.

[0056] The average thickness of the undercoat layer is preferably from 0.1 μm to 50 μm, more preferably from 0.2 μm to 40 μm, and particularly preferably from 0.3 μm to 30 μm.

[0057] The undercoat layer can be formed by preparing a coating solution for the undercoat layer containing the above-mentioned materials and a solvent, forming a coating film from the coating solution, and drying and / or curing the coating film. Examples of the solvent used in the coating solution include alcohol-based solvents, ketone-based solvents, ether-based solvents, ester-based solvents, and aromatic hydrocarbon-based solvents.

[0058] <Photosensitive layer> The photosensitive layer of an electrophotographic photoreceptor is mainly classified into (1) a multi-layer type photosensitive layer and (2) a single-layer type photosensitive layer. (1) The multi-layer type photosensitive layer has a charge generation layer containing a charge generation material and a charge transport layer containing a charge transport material. (2) The single-layer type photosensitive layer is a photosensitive layer that contains both a charge generation material and a charge transport material.

[0059] (1) Laminated photosensitive layer The laminated photosensitive layer has a charge generating layer and a charge transport layer. When no protective layer is provided on the laminated photosensitive layer, the charge transport layer serves as the surface layer.

[0060] (1-1) Charge generation layer The charge generating layer preferably contains a charge generating material and a resin.

[0061] Examples of charge-generating materials include azo pigments, perylene pigments, polycyclic quinone pigments, indigo pigments, and phthalocyanine pigments. Among these, azo pigments and phthalocyanine pigments are preferred. Among phthalocyanine pigments, oxytitanium phthalocyanine pigments, chlorogallium phthalocyanine pigments, and hydroxygallium phthalocyanine pigments are preferred. The content of the charge generating material in the charge generating layer is preferably 40% by mass to 85% by mass, and more preferably 60% by mass to 80% by mass, based on the total mass of the charge generating layer.

[0062] Examples of the resin include polyester resin, polycarbonate resin, polyvinyl acetal resin, polyvinyl butyral resin, acrylic resin, silicone resin, epoxy resin, melamine resin, polyurethane resin, phenol resin, polyvinyl alcohol resin, cellulose resin, polystyrene resin, polyvinyl acetate resin, polyvinyl chloride resin, etc. Among these, polyvinyl butyral resin is more preferred.

[0063] The charge generating layer may further contain additives such as antioxidants and ultraviolet absorbers, etc. Specific examples include hindered phenol compounds, hindered amine compounds, sulfur compounds, phosphorus compounds, and benzophenone compounds.

[0064] The average thickness of the charge generating layer is preferably 0.1 μm to 1 μm, and more preferably 0.15 μm to 0.4 μm.

[0065] The charge generating layer can be formed by preparing a coating solution for the charge generating layer containing the above materials and a solvent, forming a coating film from the coating solution, and drying the coating solution. Examples of the solvent used in the coating solution include alcohol-based solvents, sulfoxide-based solvents, ketone-based solvents, ether-based solvents, ester-based solvents, and aromatic hydrocarbon-based solvents.

[0066] (1-2) Charge transport layer The charge transport layer preferably contains a charge transport material and a resin.

[0067] Examples of the charge transport material include polycyclic aromatic compounds, heterocyclic compounds, hydrazone compounds, styryl compounds, enamine compounds, benzidine compounds, triarylamine compounds, and resins having groups derived from these materials. Among these, triarylamine compounds and benzidine compounds are preferred. The content of the charge transport material in the charge transport layer is preferably 25% by mass to 70% by mass, and more preferably 30% by mass to 55% by mass, based on the total mass of the charge transport layer.

[0068] Examples of the resin include polyester resin, polycarbonate resin, acrylic resin, polystyrene resin, etc. Among these, polycarbonate resin and polyester resin are preferred. As the polyester resin, polyarylate resin is particularly preferred. The content ratio (mass ratio) of the charge transport material to the resin is preferably 4:10 to 20:10, and more preferably 5:10 to 12:10.

[0069] The charge transport layer may also contain additives such as antioxidants, ultraviolet absorbers, plasticizers, leveling agents, slippage agents, and abrasion resistance improvers. Specific examples of the additives include hindered phenol compounds, hindered amine compounds, sulfur compounds, phosphorus compounds, benzophenone compounds, siloxane-modified resins, silicone oils, fluororesin particles, polystyrene resin particles, polyethylene resin particles, silica particles, alumina particles, and boron nitride particles.

[0070] The average thickness of the charge transport layer is preferably 5 μm to 50 μm, more preferably 8 μm to 40 μm, and particularly preferably 10 μm to 30 μm.

[0071] The charge transport layer can be formed by preparing a coating solution for the charge transport layer containing the above-mentioned materials and solvent, forming a coating film from the coating solution, and drying the coating film. Examples of solvents used in the coating solution include alcohol-based solvents, ketone-based solvents, ether-based solvents, ester-based solvents, and aromatic hydrocarbon-based solvents. Among these solvents, ether-based solvents and aromatic hydrocarbon-based solvents are preferred.

[0072] (2) Single-layer photosensitive layer The single-layer photosensitive layer can be formed by preparing a coating solution for the photosensitive layer containing a charge generating material, a charge transport material, a resin, and a solvent, forming the coating film, and drying the coating. The charge generating material, charge transport material, and resin are the same as those exemplified in "(1) Multilayer Photosensitive Layer" above. The average thickness of the single-layer photosensitive layer is preferably 5 μm to 50 μm, more preferably 8 μm to 40 μm, and particularly preferably 10 μm to 30 μm. When no protective layer is provided on the single-layer photosensitive layer, the single-layer photosensitive layer serves as the surface layer.

[0073] <Protective layer> In the present invention, a protective layer may be provided on the photosensitive layer. By providing a protective layer, durability can be improved. When a protective layer is provided on the photosensitive layer, the protective layer becomes a surface layer.

[0074] The protective layer preferably contains a charge transport material. Examples of the charge transport material include polycyclic aromatic compounds, heterocyclic compounds, hydrazone compounds, styryl compounds, enamine compounds, benzidine compounds, triarylamine compounds, and resins having groups derived from these materials. Among these, triarylamine compounds and benzidine compounds are preferred.

[0075] The protective layer is preferably formed as a cured film by polymerizing a composition containing a monomer having a polymerizable functional group. Examples of the reaction include thermal polymerization, photopolymerization, and radiation polymerization. Examples of the polymerizable functional group possessed by the monomer having a polymerizable functional group include an acryloyloxy group and a methacryloyloxy group. A material having charge transport capability may be used as the monomer having a polymerizable functional group.

[0076] The protective layer may contain additives such as antioxidants, ultraviolet absorbers, plasticizers, leveling agents, slipping agents, and abrasion resistance improvers. Specific examples of such additives include hindered phenol compounds, hindered amine compounds, sulfur compounds, phosphorus compounds, benzophenone compounds, siloxane-modified resins, silicone oils, fluororesin particles, polystyrene resin particles, polyethylene resin particles, silica particles, alumina particles, and boron nitride particles.

[0077] The average thickness of the protective layer is preferably 0.5 μm to 10 μm, and more preferably 1 μm to 7 μm.

[0078] The protective layer can be formed by preparing a coating solution for the protective layer containing the above-mentioned materials and solvent, forming a coating film from this, and drying and / or curing the coating film. Examples of the solvent used in the coating solution include alcohol-based solvents, ketone-based solvents, ether-based solvents, sulfoxide-based solvents, ester-based solvents, and aromatic hydrocarbon-based solvents.

[0079] The coating film of the coating liquid for the protective layer can be cured by heat, ultraviolet light, or electron beams. In order to maintain the strength of the protective layer (i.e., the surface layer) and the durability of the electrophotographic photoreceptor, it is preferable to use ultraviolet light or electron beams for curing.

[0080] Polymerization using an electron beam is preferable because it results in a very dense (high-density) cured product (three-dimensional crosslinked structure) and a protective layer with higher durability. When irradiating with an electron beam, examples of accelerators that can be used include a scanning type, an electrocurtain type, a broad beam type, a pulse type, and a laminar type.

[0081] When an electron beam is used, the acceleration voltage of the electron beam is preferably 120 kV or less from the viewpoint of suppressing deterioration of material properties due to the electron beam without impairing polymerization efficiency. The electron beam absorbed dose on the surface of the coating film of the coating solution for the protective layer is preferably 1 kGy to 50 kGy, more preferably 5 kGy to 10 kGy.

[0082] When the coating film is cured (polymerized) using an electron beam, it is preferable to irradiate the coating film with the electron beam in an inert gas atmosphere and then heat the coating film in the inert gas atmosphere, for example, nitrogen, argon, or helium, in order to prevent the polymerization from being inhibited by oxygen.

[0083] After irradiation with ultraviolet rays or electron beams, the electrophotographic photosensitive member is preferably heated to 100° C. to 170° C. This makes it possible to obtain a protective layer that has even higher durability and suppresses image defects.

[0084] <Surface layer> In the present invention, the surface layer is a layer provided on the outermost surface of the electrophotographic photosensitive member. In an electrophotographic photoreceptor having a protective layer, the protective layer is the surface layer. In an electrophotographic photoreceptor not having a protective layer, if the photosensitive layer is a multi-layer type photosensitive layer, the charge transport layer is the surface layer, and if the photosensitive layer is a single-layer type photosensitive layer, the photosensitive layer is the surface layer. When the surface layer is a protective layer, the photosensitive layer is preferably a laminated type photosensitive layer, and the surface layer is preferably a protective layer provided on the charge transport layer.

[0085] [Process cartridges, electrophotographic devices] The process cartridge of the present invention is characterized by integrally supporting the electrophotographic photosensitive member of the present invention and at least one means selected from the group consisting of a charging means, a developing means, a transfer means, and a cleaning means, and being detachably mountable to the main body of the electrophotographic apparatus.

[0086] The electrophotographic apparatus of the present invention is characterized by comprising the electrophotographic photosensitive member of the present invention, a charging means, an exposing means, a developing means and a transferring means.

[0087] FIG. 1 shows an example of the schematic configuration of an electrophotographic apparatus having a process cartridge equipped with an electrophotographic photosensitive member.

[0088] A cylindrical electrophotographic photoreceptor 1 is rotated around an axis 2 in the direction of the arrow at a predetermined peripheral speed. The surface of the electrophotographic photoreceptor 1 is charged to a predetermined positive or negative potential by a charging unit 3. While the figure shows a roller charging method using a roller-type charging member, other charging methods, such as corona charging, proximity charging, and injection charging, may also be used. An exposure unit (not shown) irradiates the charged surface of the electrophotographic photoreceptor 1 with exposure light 4, forming an electrostatic latent image corresponding to the desired image information. The electrostatic latent image formed on the surface of the electrophotographic photoreceptor 1 is developed with toner contained in a developing unit 5, forming a toner image on the surface of the electrophotographic photoreceptor 1. The toner image formed on the surface of the electrophotographic photoreceptor 1 is transferred to a transfer material 7 by a transfer unit 6. The transfer material 7 to which the toner image has been transferred is transported to a fixing unit 8, where the toner image is fixed and printed out from the electrophotographic device. The electrophotographic device may also have a cleaning unit 9 for removing toner and other deposits remaining on the surface of the electrophotographic photoreceptor 1 after transfer. Furthermore, a so-called cleanerless system may be used in which the deposits are removed by the developing unit 5 or the like without providing a separate cleaning unit 9. The electrophotographic apparatus may have a charge-removing mechanism that performs a charge-removing process on the surface of the electrophotographic photosensitive member 1 with pre-exposure light 10 from pre-exposure unit (not shown). Furthermore, guide unit 12 such as a rail may be provided in order to mount and remove the process cartridge 11 of the present invention to and from the main body of the electrophotographic apparatus.

[0089] The electrophotographic photoreceptor of the present invention can be used in laser beam printers, LED printers, copying machines, facsimiles, and combination machines thereof. [Example]

[0090] The present invention will be described in more detail below using examples and comparative examples. The present invention is not limited to the following examples without departing from the gist of the present invention. In the following examples, "parts" are by mass unless otherwise specified.

[0091] Example 1 An aluminum cylinder with a diameter of 30 mm, a length of 357.5 mm, and a wall thickness of 1 mm was used as the support (conductive support).

[0092] Next, zinc oxide particles (specific surface area: 19 m 2 100 parts of zinc oxide (ZnO 2 0.01g / g, powder resistivity: 4.7×106 Ω·cm) were mixed with 500 parts of toluene and stirred, to which 0.8 parts of a silane coupling agent was added and stirred for 6 hours. The toluene was then distilled off under reduced pressure, and the particles were dried by heating at 130°C for 6 hours to obtain surface-treated zinc oxide particles. The silane coupling agent used was KBM602 (compound name: N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane) manufactured by Shin-Etsu Chemical Co., Ltd.

[0093] Next, 15 parts of a polyvinyl butyral resin (trade name: BM-1, manufactured by Sekisui Chemical Co., Ltd., weight-average molecular weight: 40,000) as a polyol resin and 15 parts of a blocked isocyanate (trade name: Sumidur 3175, manufactured by Sumika Covestro Urethane Co., Ltd.) were dissolved in a mixed solution of 73.5 parts of methyl ethyl ketone and 73.5 parts of 1-butanol. To this solution, 80.8 parts of the surface-treated zinc oxide particles and 0.8 parts of 2,3,4-trihydroxybenzophenone (manufactured by Tokyo Chemical Industry Co., Ltd.) were added, and the mixture was dispersed in a sand mill using glass beads with a diameter of 0.8 mm in an atmosphere of 23±3°C for 3 hours. After dispersion, 0.01 parts of silicone oil (trade name: SH28PA, manufactured by Dow Corning Toray Co., Ltd.) and 5.6 parts of cross-linked polymethyl methacrylate (PMMA) particles (trade name: TECHPOLYMER SSX-103, manufactured by Sekisui Chemical Co., Ltd., average primary particle size 3 μm) were added and stirred to prepare a coating solution for the undercoat layer. This coating solution for the undercoat layer was dip-coated onto the aluminum cylinder to form a coating film, and the resulting coating film was dried at 160° C. for 40 minutes to form an undercoat layer with a thickness of 18 μm.

[0094] Next, hydroxygallium phthalocyanine crystals with strong peaks at 7.4° and 28.2° (with a Bragg angle 2θ of ±0.2°) in CuKα characteristic X-ray diffraction were prepared. 20 parts of these hydroxygallium phthalocyanine crystals, 0.2 parts of a compound represented by the following formula (A), 10 parts of polyvinyl butyral resin (product name: S-LEC BX-1, manufactured by Sekisui Chemical Co., Ltd.), and 600 parts of cyclohexanone were dispersed for 4 hours using a sand mill equipped with 1 mm diameter glass beads. Then, 700 parts of ethyl acetate was added to prepare a charge generation layer coating solution. This charge generation layer coating solution was dip-coated onto the undercoat layer to form a coating film, and the resulting coating film was dried in an oven at 80°C for 15 minutes to form a charge generation layer with a thickness of 0.17 μm. [ka]

[0095] Next, 30 parts of a compound (charge transport material) represented by the following formula (B), 60 parts of a compound (charge transport material) represented by the following formula (C), 10 parts of a compound represented by the following formula (D), 100 parts of a polycarbonate resin (trade name: Iupilon Z400, manufactured by Mitsubishi Engineering-Plastics Corporation, bisphenol Z type), 0.02 parts of a polycarbonate having a structural unit represented by the following formula (E) (viscosity average molecular weight Mv: 40,000), and 0.2 parts of a compound represented by formula (1) (exemplary compound 1-3) were dissolved in a solvent of 600 parts of mixed xylene and 200 parts of dimethoxymethane to prepare a coating solution 1 for a charge transport layer. [ka] (In formula (E), 0.95 and 0.05 are the molar ratios (copolymerization ratios) of the two structural units.) This charge transport layer coating liquid 1 was dip coated onto the charge generation layer to form a coating film, and the resulting coating film was dried at 100°C for 30 minutes to form a charge transport layer (surface layer) with a thickness of 18 μm. In this way, an electrophotographic photoreceptor E1 was produced.

[0096] Example 2 An electrophotographic photoreceptor E2 was produced in the same manner as in Example 1, except that the exemplary compound 1-3 contained in the charge transport coating liquid was changed to the exemplary compound 1-7.

[0097] Example 3 An electrophotographic photoreceptor E3 was produced in the same manner as in Example 1, except that the exemplary compound 1-3 contained in the charge transport coating liquid was changed to the exemplary compound 1-8.

[0098] Example 4 An electrophotographic photoreceptor E4 was produced in the same manner as in Example 3, except that the amount of Exemplified Compound 1-8 contained in the charge transport coating liquid was changed from 0.2 parts to 1 part.

[0099] Example 5 An electrophotographic photoreceptor E5 was produced in the same manner as in Example 3, except that the amount of Exemplified Compound 1-8 contained in the charge transport coating liquid was changed from 0.2 parts to 2 parts.

[0100] Example 6 An electrophotographic photoreceptor E6 was produced in the same manner as in Example 3, except that the amount of Exemplified Compound 1-8 contained in the charge transport coating liquid was changed from 0.2 parts to 4 parts.

[0101] Example 7 An electrophotographic photoreceptor E7 was produced in the same manner as in Example 3, except that the amount of Exemplified Compound 1-8 contained in the charge transport coating liquid was changed from 0.2 parts to 0.02 parts.

[0102] Example 8 An electrophotographic photoreceptor E8 was produced in the same manner as in Example 3, except that the amount of Exemplified Compound 1-8 contained in the charge transport coating liquid was changed from 0.2 parts to 0.01 parts.

[0103] Example 9 In the same manner as in Example 1, the charge generation layer was formed. Next, 30 parts of the compound represented by formula (B) above (charge transport material), 60 parts of the compound represented by formula (C) above (charge transport material), 10 parts of the compound represented by formula (D) above, 100 parts of a polycarbonate resin (trade name: Iupilon Z400, manufactured by Mitsubishi Engineering Plastics Corporation, bisphenol Z type), and 0.02 parts of a polycarbonate having a structural unit represented by formula (E) above (viscosity average molecular weight Mv: 20,000) were dissolved in a solvent of 600 parts of mixed xylene and 200 parts of dimethoxymethane to prepare coating solution 2 for the charge transport layer. This charge transport layer coating solution 2 was dip coated onto the charge generating layer to form a coating film, and the resulting coating film was dried at 100° C. for 30 minutes to form a charge transport layer with a thickness of 18 μm.

[0104] Next, 0.1 parts of the compound represented by formula (1) (exemplary compound 1-3), 50 parts of the compound represented by formula (2) (exemplary compound 2-1), 50 parts of the compound represented by formula (B) (charge transport material), 75 parts of 2-propanol, and 75 parts of tetrahydrofuran were dissolved to prepare a protective layer coating solution 1. This protective layer coating solution 1 was dip-coated onto the charge transport layer to form a coating film. The resulting coating film was dried at 50°C for 5 minutes. Next, under a nitrogen atmosphere, the substrate (irradiated object) was rotated at a speed of 200 rpm under conditions of an acceleration voltage of 70 kV and a beam current of 5.0 mA, and the coating film was irradiated with an electron beam for 1.5 seconds. The temperature of the coating film was then raised over 10 seconds to 25°C to 120°C, thereby curing the coating film. The absorbed dose of the electron beam was measured at this time to be 15 kGy, and the oxygen concentration from the electron beam irradiation to the subsequent heat treatment was 20 ppm or less. Next, the coating film was naturally cooled in the atmosphere to a temperature of 25°C, and then heat-treated at 100°C for 15 minutes to form a protective layer (surface layer) with a thickness of 5 μm. In this way, an electrophotographic photoreceptor E9 was produced.

[0105] Example 10 An electrophotographic photoreceptor E10 was produced in the same manner as in Example 9, except that the exemplary compound 2-1 contained in the protective layer coating liquid was changed to a compound represented by the following formula (G). [ka]

[0106] Example 11 An electrophotographic photoreceptor E11 was produced in the same manner as in Example 9, except that exemplary compound 2-1 contained in the protective layer coating solution was changed to a compound represented by the above formula (G), and the compound represented by the above formula (B) was changed to a compound represented by the formula (CT-1) (exemplary compound CT1-3).

[0107] Example 12 An electrophotographic photoreceptor E12 was produced in the same manner as in Example 9, except that exemplary compound 2-1 contained in the protective layer coating solution was changed to a compound represented by the following formula (H), and the compound represented by the above formula (B) was changed to a compound represented by formula (CT-1) (exemplary compound CT1-5). [ka]

[0108] Example 13 The same procedures as in Example 9 were carried out up to the formation of the charge transport layer. Next, 0.1 parts of a compound represented by formula (1) (exemplary compound 1-3), 20 parts of a compound represented by formula (2) (exemplary compound 2-1), 50 parts of a compound represented by formula (CT-1) (exemplary compound CT1-5), 30 parts of polytetrafluoroethylene particles (Lubron L-2, manufactured by Daikin Industries, Ltd.), 2 parts of a fluorine-containing acrylic resin (weight average molecular weight: 83,000, copolymerization ratio (F1) / (F2)=1 / 1 (molar ratio)) having a repeating structural unit represented by the following formula (F1) and a repeating structural unit represented by the following formula (F2), 75 parts of 1-propanol, and 75 parts of 1,1,2,2,3,3,4-heptafluorocyclopentane (trade name: Zeorora H, manufactured by Nippon Zeon Co., Ltd.) were mixed, and the resulting solution was dispersed using an ultra-high speed disperser. Thereafter, the solution was filtered through a Polyflon filter (trade name: PF-060, manufactured by Advantec Toyo Co., Ltd.) to prepare a coating solution 2 for protective layer. [ka]

[0109] This protective layer coating solution 2 was dip-coated onto the charge transport layer to form a coating film. The resulting coating film was dried at 50°C for 5 minutes. Next, under a nitrogen atmosphere, the substrate (irradiated object) was rotated at a speed of 200 rpm under conditions of an acceleration voltage of 70 kV and a beam current of 5.0 mA, and the coating film was irradiated with an electron beam for 1.5 seconds. The temperature of the coating film was then raised over 10 seconds to 25°C to 120°C, thereby curing the coating film. The absorbed dose of the electron beam was measured at this time to be 15 kGy, and the oxygen concentration from the electron beam irradiation to the subsequent heat treatment was 20 ppm or less. Next, the coating film was naturally cooled in the atmosphere to a temperature of 25°C, and then heat-treated at 100°C for 15 minutes to form a protective layer (surface layer) with a thickness of 5 μm. In this way, an electrophotographic photoreceptor E13 was produced.

[0110] Example 14 An electrophotographic photoreceptor E14 was produced in the same manner as in Example 13, except that the exemplary compound CT1-5 contained in the protective layer coating liquid was changed to the exemplary compound CT1-7.

[0111] Example 15 An electrophotographic photoreceptor E15 was produced in the same manner as in Example 14, except that the exemplary compound 1-3 contained in the protective layer coating liquid was changed to the exemplary compound 1-7.

[0112] Example 16 An electrophotographic photoreceptor 16 was produced in the same manner as in Example 14, except that the exemplary compound 1-3 contained in the protective layer coating liquid was changed to the exemplary compound 1-9.

[0113] Example 17 An electrophotographic photoreceptor E17 was produced in the same manner as in Example 14, except that the exemplary compound 1-3 contained in the protective layer coating liquid was changed to the exemplary compound 1-4.

[0114] Example 18 An electrophotographic photoreceptor E18 was produced in the same manner as in Example 14, except that the amount of Exemplified Compound 1-3 contained in the protective layer coating liquid was changed from 0.1 part to 0.5 parts.

[0115] Example 19 An electrophotographic photoreceptor E19 was produced in the same manner as in Example 14, except that the amount of Exemplified Compound 1-3 contained in the protective layer coating liquid was changed from 0.1 part to 1 part.

[0116] Example 20 An electrophotographic photoreceptor E20 was produced in the same manner as in Example 14, except that the amount of Exemplified Compound 1-3 contained in the protective layer coating liquid was changed from 0.1 parts to 2 parts.

[0117] Example 21 An electrophotographic photoreceptor E21 was produced in the same manner as in Example 14, except that the amount of Exemplified Compound 1-3 contained in the protective layer coating solution 2 was changed from 0.1 part to 0.01 part.

[0118] Example 22 An electrophotographic photoreceptor E22 was produced in the same manner as in Example 14, except that the amount of Exemplified Compound 1-3 contained in the protective layer coating solution 2 was changed from 0.1 part to 0.05 part.

[0119] (Comparative Example 1) An electrophotographic photoreceptor C1 was produced in the same manner as in Example 1, except that the compound represented by formula (1) (exemplified compound 1-3) was not used.

[0120] (Comparative Example 2) An electrophotographic photoreceptor C2 was produced in the same manner as in Example 13, except that the compound represented by formula (1) (exemplified compound 1-3) was not used.

[0121] (Comparative Example 3) An electrophotographic photoreceptor C3 was produced in the same manner as in Example 13, except that the compound represented by formula (1) (exemplified compound 1-3) was changed to a compound represented by the following formula (I). [ka]

[0122] [evaluation] <Electrical characteristic evaluation> The electrophotographic photoreceptors manufactured in each example and comparative example were mounted in the cyan station of a modified electrophotographic apparatus (copier) (product name: iR-ADV C5255, manufactured by Canon Inc.) as an evaluation apparatus, and evaluation was performed under the conditions shown below. The surface potential of the electrophotographic photoreceptor was measured by removing the developing cartridge from the evaluation apparatus, attaching a potential probe (product name: Model 6000B-8, manufactured by Trek) to the cartridge, and using a surface potentiometer (Model 344, manufactured by Trek). First, the dark potential (VD) of the electrophotographic photoreceptor used for evaluation was adjusted to −750 V. Next, the light potential (VL) of the surface of the electrophotographic photoreceptor was evaluated under constant exposure light intensity conditions of the exposure device. This evaluation was performed in a low-temperature, low-humidity environment of 15°C and 10% RH, and a high-temperature, high-humidity environment of 30°C and 80% RH. The VL in the evaluation in the low-temperature, low-humidity environment was designated VL(LL), and the VL in the evaluation in the high-temperature, high-humidity environment was designated VL(HH). In the present invention, it was determined that when VL(LL) and VL(HH) are each less than 250 V, there is no problem in terms of the characteristics of the electrophotographic photosensitive member.

[0123] <Environmental change assessment> The value of "VL(HH)-VL(LL)" was calculated as a result of environmental variation. In the present invention, it was determined that if the environmental fluctuation (VL(HH)-VL(LL)) is less than 40 V, there is no problem in terms of the characteristics of the electrophotographic photosensitive member.

[0124] The evaluation results of Examples 1 to 22 and Comparative Examples 1 to 3 are shown in Table 1. [Table 1]

[0125] As a result of the evaluation, it was found that the environmental fluctuations were sufficiently suppressed in the examples and presented no problems, whereas the environmental fluctuations were problematic in the comparative examples. [Explanation of symbols]

[0126] 1. Electrophotographic photoreceptor 2-axis 3. Charging means 4 Exposure light 5. Developing method 6 Transfer Method 7 Transfer material 8 Fixing means 9 Cleaning Method 10 Pre-exposure light 11 Process cartridge 12 Guidance means 21 Support 22 Undercoat layer 23 Charge generation layer 24 Charge transport layer 25 Protective layer (surface layer)

Claims

1. 1. An electrophotographic photoreceptor having a support and a surface layer, wherein the surface layer contains a compound represented by the following formula (1): 【Chemical 1】 (In the above formula (1), R １１ ~R １３ each independently represents an alkylene group having 1 to 6 carbon atoms. １１ ~Q １３ each independently represents a hydroxy group or a carboxy group.

2. 2. The electrophotographic photoreceptor according to claim 1, wherein the content of the compound represented by formula (1) in the surface layer is 0.01% by mass to 1% by mass with respect to the total mass of the surface layer.

3. 3. The electrophotographic photoreceptor according to claim 1, wherein the content of the compound represented by formula (1) in the surface layer is 0.01% by mass to 0.5% by mass with respect to the total mass of the surface layer.

4. Q in the formula (1) １１ ~Q １３ 4. The electrophotographic photoreceptor according to claim 1, wherein is a hydroxy group.

5. R in the formula (1) １１ ~R １３ The electrophotographic photoreceptor according to any one of claims 1 to 4, wherein each of the groups independently represents an alkylene group having 1 or 2 carbon atoms.

6. 6. The electrophotographic photoreceptor according to claim 1, wherein the surface layer contains a polymer of a composition containing a compound having a chain-polymerizable functional group.

7. The electrophotographic photoreceptor according to claim 6 , wherein the composition contains a compound represented by the following formula (2): 【Chemistry 2】 (In the above formula (2), R ２１ ~R ２３ each independently represents an alkylene group having 1 to 6 carbon atoms. ２１ ~Q ２３ each independently represents an acryloyloxy group or a methacryloyloxy group.

8. 8. The electrophotographic photoreceptor according to claim 6, wherein the composition contains a compound represented by the following formula (CT-1) or (CT-2): 【Chemistry 3】 (In the above formula (CT-1), Ar １１ ~Ar １３ each independently represents a substituted aryl group or an unsubstituted aryl group. The substituent that the substituted aryl group may have is an alkyl group having 1 to 6 carbon atoms or a monovalent functional group represented by any one of the following formulas (P-1) to (P-3). However, the compound represented by the above formula (CT-1) has at least one monovalent functional group represented by any one of the following formulas (P-1) to (P-3). 【Chemistry 4】 (In the above formula (P-1), Z １１ represents a single bond or an alkylene group having 1 to 6 carbon atoms. １１ represents a hydrogen atom or a methyl group. 【Chemistry 5】 (In the above formula (P-2), Z ２１ represents a single bond or an alkylene group having 1 to 6 carbon atoms. 【Chemistry 6】 (In the above formula (P-3), Z ３１ represents a single bond or an alkylene group having 1 to 6 carbon atoms. 【Chemistry 7】 (In the above formula (CT-2), Ar ２１ ~Ar ２４ each independently represents a substituted aryl group or an unsubstituted aryl group. ２５ represents a substituted arylene group or an unsubstituted arylene group. The substituent that the substituted aryl group may have is an alkyl group having 1 to 6 carbon atoms or a monovalent functional group represented by the following formulas (P-1) to (P-3). The substituent that the substituted arylene group may have is an alkyl group having 1 to 6 carbon atoms or a monovalent functional group represented by the following formulas (P-1) to (P-3). However, the compound represented by the above formula (CT-2) has at least one monovalent functional group represented by any of the following formulas (P-1) to (P-3). 【Chemistry 8】 (In the above formula (P-1), Z １１ represents a single bond or an alkylene group having 1 to 6 carbon atoms. １１ represents a hydrogen atom or a methyl group. 【Chemistry 9】 (In the above formula (P-2), Z ２１ represents a single bond or an alkylene group having 1 to 6 carbon atoms. 【Chemistry 10】 (In the above formula (P-3), Z ３１ represents a single bond or an alkylene group having 1 to 6 carbon atoms.

9. The composition contains a compound represented by formula (1), the content of the compound represented by formula (1) in the composition is 0.015% by mass to 1% by mass relative to the content of the compound represented by formula (CT-1) or (CT-2) in the composition; The electrophotographic photoreceptor according to claim 8.

10. the electrophotographic photoreceptor has a charge generating layer provided on the support and a charge transport layer provided on the charge generating layer, the surface layer is a layer provided on the charge transport layer; The electrophotographic photoreceptor according to any one of claims 1 to 9.

11. A process cartridge that integrally supports the electrophotographic photosensitive member according to any one of claims 1 to 10 and at least one means selected from the group consisting of a charging means, a developing means, a transfer means, and a cleaning means, and is detachably mountable to a main body of an electrophotographic apparatus.

12. 11. An electrophotographic apparatus comprising the electrophotographic photoreceptor according to claim 1, a charging means, an exposure means, a developing means, and a transfer means.

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