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

Abstract

To provide an electrophotographic photoreceptor comprising a surface layer that offers superior wear resistance, suppresses image defects due to poor dispersibility of fluorine atom-containing resin particles, and suppresses electric potential variations associated with repetitive use.SOLUTION: An electrophotographic photoreceptor with a surface layer is provided, the surface layer containing: a cured product of a charge transport compound and at least one triazine compound selected from a group consisting of guanamine compounds and melamine compounds; a fluorine atom-containing resin particles; and a polymer A having a specific structure represented by a formula (1) below.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] Electrophotographic photoreceptors that use organic materials as photoconductive substances (charge generating substances and charge transport substances) are widely used as electrophotographic photoreceptors mounted in electrophotographic apparatuses.

[0003] In recent years, various functions have been required of the surface layer of an electrophotographic photosensitive member, such as a longer life, higher image quality, stabilization of image quality during repeated use, and reduction of cleaning defects.

[0004] Patent Document 1 discloses an electrophotographic photoreceptor that has excellent cleanability due to the inclusion of fluorine atom-containing resin particles in the surface layer.

[0005] Patent Document 2 further discloses a technique for improving the dispersibility of fluorine atom-containing resin particles contained in the surface layer by using a fluorine atom-containing (meth)acrylic polymer with a specific structure as a dispersant.

[0006] Patent Document 3 discloses a technique in which a crosslinked product of a guanamine compound or melamine compound with a charge transporting material is contained in the surface layer of an electrophotographic photosensitive member in order to improve the abrasion resistance of the surface layer. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 11-202531 [Patent Document 2] Japanese Patent Application Laid-Open No. 2009-104145 [Patent Document 3] Japanese Patent Application Laid-Open No. 2012-203253 Summary of the Invention [Problem to be solved by the invention]

[0008] As a result of investigations by the present inventors, it was found that there is room for further improvement in the technology disclosed in Patent Document 3 in terms of being able to suppress potential fluctuations during repeated use without impairing the dispersibility of the fluorine atom resin particles contained in the surface layer.

[0009] One aspect of the present disclosure is to provide an electrophotographic photoreceptor in which image defects due to poor dispersion of fluorine atom-containing resin particles are suppressed and potential fluctuations during repeated use are suppressed. Another aspect of the present disclosure is directed to providing a process cartridge having the electrophotographic photosensitive member mounted thereon, and an electrophotographic apparatus having the electrophotographic photosensitive member. Another aspect of the present disclosure is directed to providing a method for producing the electrophotographic photoreceptor. [Means for solving the problem]

[0010] According to one aspect of the present disclosure, there is provided an electrophotographic photoreceptor having a surface layer, the surface layer comprising a cured product of a charge transporting compound and at least one triazine compound selected from the group consisting of a guanamine compound and a melamine compound, fluorine atom-containing resin particles, and a structural unit represented by the following formula (1): and a structural unit represented by the following formula (2): and a polymer A having the formula: [ka] (In formula (1), R 11 represents a hydrogen atom or a methyl group, and R 12 represents a single bond, a methylene group, or an ethylene group, n is an integer of 1 or more, and Rf 1 each independently represents a perfluoroalkylene group having 1 to 5 carbon atoms or a perfluoroalkylidene group having 1 to 5 carbon atoms, and Rf 2 represents a perfluoroalkyl group having 1 or more and 5 or less carbon atoms. [ka] (In formula (2), Y A1 represents an unsubstituted alkylene group, Y B represents an unsubstituted alkylene group, an alkylene group substituted with a halogen atom, an alkylene group substituted with a hydroxy group, an ester bond (-COO-), an amide bond (-NHCO-), a urethane bond (-NHCOO-), or a divalent linking group derived by combining one or more selected from these groups and bonds with -O- or -S-, or a single bond; Z A represents a structure represented by the following formula (2A): R 21 represents a hydrogen atom or a methyl group, R 22 indicates a methyl group, m is an integer between 25 and 150. [ka] (In formula (2A), Z A1 indicates a methyl group.)

[0011] According to another aspect of the present disclosure, there is provided 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 attachable to the main body of the electrophotographic apparatus. According to another aspect of the present disclosure, there is provided an electrophotographic apparatus having the electrophotographic photoreceptor, a charging unit, an exposure unit, a developing unit, and a transfer unit. According to another aspect of the present disclosure, there is provided a method for producing the electrophotographic photoreceptor. [Effects of the Invention]

[0012] According to one aspect of the present disclosure, it is possible to provide an electrophotographic photoreceptor in which image defects due to poor dispersion of fluorine atom-containing resin particles are suppressed in a surface layer having excellent abrasion resistance, and potential fluctuations during repeated use are suppressed. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a schematic diagram illustrating an example of a configuration of an electrophotographic photoreceptor according to the present disclosure. [Figure 2] FIG. 1 is a schematic view illustrating an example of a process cartridge having an electrophotographic photosensitive member. [Figure 3] 1 is a schematic view showing an example of a process cartridge in which an electrophotographic photosensitive member is mounted, and an electrophotographic apparatus including the process cartridge. DETAILED DESCRIPTION OF THE INVENTION

[0014] The present invention will be described in detail below with reference to preferred embodiments. The electrophotographic photoreceptor of the present invention has a surface layer, and the surface layer comprises a cured product of a charge transporting compound and at least one triazine compound selected from the group consisting of guanamine compounds and melamine compounds, fluorine atom-containing resin particles, and a structural unit represented by the following formula (1): and a structural unit represented by the following formula (2): and a polymer A having the following formula: [ka] (In formula (1), R 11 represents a hydrogen atom or a methyl group, and R 12 represents a single bond, a methylene group, or an ethylene group, n is an integer of 1 or more, and Rf 1 each independently represents a perfluoroalkylene group having 1 or more and 5 or less carbon atoms, or a perfluoroalkylidene group having 1 or more and 5 or less carbon atoms, and Rf 2 represents a perfluoroalkyl group having 1 or more and 5 or less carbon atoms. [ka] (In formula (2), Y A1 represents an unsubstituted alkylene group, Y B represents an unsubstituted alkylene group, an alkylene group substituted with a halogen atom, an alkylene group substituted with a hydroxy group, an ester bond (-COO-), an amide bond (-NHCO-), a urethane bond (-NHCOO-), or a divalent linking group derived by combining one or more selected from these groups and bonds with -O- or -S-, or a single bond; ZA represents a structure represented by the following formula (2A): R 21 represents a hydrogen atom or a methyl group, R 22 indicates a methyl group, m is an integer between 25 and 150. [ka] (In formula (2A), Z A1 indicates a methyl group.)

[0015] The present inventors believe that the polymer A having the structural unit represented by the formula (1) acts as a dispersant for fluorine atom-containing resin particles in the step of preparing a surface layer coating liquid for forming the surface layer of an electrophotographic photosensitive member.

[0016] The present inventors speculate as follows why the electrophotographic photoreceptor of the present disclosure has excellent dispersibility of fluorine atom-containing resin particles in the surface layer and excellent effect of suppressing potential fluctuations during repeated use.

[0017] When the surface layer of an electrophotographic photosensitive member contains a cured product of a charge transport compound and at least one triazine compound selected from the group consisting of guanamine compounds and melamine compounds, it is considered that charge transfer in the surface layer is carried out by the moiety derived from the charge transport compound and the moiety derived from the triazine compound in the cured product, respectively.

[0018] When fluorine atom-containing resin particles are dispersed in this surface layer using a dispersant (polymer), potential fluctuations may occur during repeated use of the electrophotographic photosensitive member. This is thought to be because when the dispersant (polymer) is present in the surface layer without adhering to the fluorine atom-containing resin particles, the dispersant (polymer) interferes with charge transfer in the portion of the cured product derived from the triazine compound.

[0019] As a result of investigations by the inventors, it was found that when polymer A having a structural unit containing a -(CF2)n- chain is incorporated into the surface layer, the presence of an oxygen atom between the -(CF2)n- chains has the effect of suppressing charge retention. In addition, the present inventors have found that it is important to incorporate polymer A having a structural unit represented by the above formula (1) into the surface layer so as not to impair the function of polymer A to disperse fluorine atom-containing resin particles, and that this makes it possible to suppress potential fluctuations due to repeated use without impairing the dispersibility of fluorine atom-containing resin particles in the surface layer.

[0020] <Polymer A having a structural unit represented by formula (1)> The surface layer of the electrophotographic photoreceptor of the present disclosure contains a polymer A having a structural unit represented by the following formula (1). [ka] (In formula (1), R 11 R represents a hydrogen atom or a methyl group. 12 represents a single bond, a methylene group, or an ethylene group, and n is an integer of 1 or more. 1 each independently represents a perfluoroalkylene group having 1 to 5 carbon atoms or a perfluoroalkylidene group having 1 to 5 carbon atoms, and Rf 2 represents a perfluoroalkyl group having 1 to 5 carbon atoms.

[0021] In the formula (1), R 11 is a hydrogen atom or a methyl group. R 12 represents a single bond, a methylene group, or an ethylene group. From the viewpoint of the function of dispersing fluorine atom-containing resin particles, a methylene group is preferred.

[0022] n is an integer of 1 or more. Furthermore, from the viewpoint of the function of dispersing fluorine atom-containing resin particles in the surface layer of the electrophotographic photoreceptor of the present disclosure, n is preferably 2 or less.

[0023] Rf 1 are each independently a perfluoroalkylene group having 1 to 5 carbon atoms or a perfluoroalkylidene group having 1 to 5 carbon atoms. Rf 1 When the number of carbon atoms is 6 or more, charge retention between the structural unit represented by the formula (1) and the cured product contained in the surface layer cannot be sufficiently suppressed, and potential fluctuations cannot be sufficiently suppressed during repeated use of the electrophotographic photosensitive member. Rf 1 From the viewpoint of achieving both suppression of charge retention and dispersibility of the fluorine atom-containing resin particles, the number of carbon atoms is more preferably a perfluoroalkylene group having 2 to 4 carbon atoms or a perfluoroalkylidene group having 2 to 4 carbon atoms.

[0024] Rf 2 is a perfluoroalkyl group having 1 to 5 carbon atoms. Rf 2 When the number of carbon atoms is 6 or more, charge retention between the structural unit represented by the formula (1) and the cured product contained in the surface layer cannot be sufficiently suppressed, and potential fluctuations cannot be sufficiently suppressed during repeated use of the electrophotographic photosensitive member. Rf 2 From the viewpoint of achieving both suppression of charge retention and dispersibility of the fluorine atom-containing resin particles, is preferably a perfluoroalkyl group having 2 to 4 carbon atoms, and more preferably a perfluoroalkyl group having 3 or less carbon atoms.

[0025] In addition, n Rf in the formula (1) 1 , and Rf 2 The total number of carbon atoms is preferably 5 or more and 8 or less from the viewpoint of both suppressing charge retention in the surface layer of the electrophotographic photoreceptor of the present disclosure and achieving good dispersibility of the fluorine atom-containing resin particles.

[0026] Examples of the structural unit represented by formula (1) contained in polymer A having the structural unit represented by formula (1) used in the present disclosure include the structures shown below.

[0027] [ka]

[0028] From the viewpoint of improving the dispersibility of fluorine-containing resin particles, the structural unit represented by formula (1) in polymer A contained in the surface layer of the electrophotographic photoreceptor of the present disclosure preferably accounts for 5% to 95% by number of all structural units in polymer A. Furthermore, the structural unit represented by formula (1) more preferably accounts for 50% to 95% by number, and even more preferably 70% to 90% by number, of all structural units in polymer A. Furthermore, the structural unit represented by the formula (1) preferably accounts for 0.1% by mass or more and 80% by mass or less, more preferably 1% by mass or more and 80% by mass or less, and even more preferably 4% by mass or more and 66% by mass or less, based on the total mass of the polymer contained in the polymer A.

[0029] The polymer A is preferably a polymer having a structural unit represented by the formula (1) and a structural unit represented by the following formula (2). [ka] (In formula (2), Y A1 represents an unsubstituted alkylene group, Y B represents an unsubstituted alkylene group, an alkylene group substituted with a halogen atom, an alkylene group substituted with a hydroxy group, an ester bond (-COO-), an amide bond (-NHCO-), a urethane bond (-NHCOO-), or a divalent linking group derived by combining one or more selected from these groups and bonds with -O- or -S-, or a single bond; Z A represents a structure represented by the following formula (2A), a cyano group, or a phenyl group, R 21 , and R 22 each independently represents a hydrogen atom or a methyl group, m is an integer between 25 and 150. [ka] (In formula (2A), Z A1 represents an alkyl group having 1 to 4 carbon atoms. In formula (2), Y B When represents an ester bond, -Y A1 -Y B -CH2- is -Y A1 -CO-O-CH2- and -Y A1 -O-CO-CH2-, and preferably -Y A1 -CO-O-CH2-. In addition, in formula (2), Y B represents an amide bond, -Y A1 -Y B -CH2- is -Y A1 -NH-CO-CH2- and -Y A1 -CO-NH-CH2-, and preferably -Y A1 -NH-CO-CH2-. In addition, in formula (2), Y B If is a urethane bond, -Y A1 -Y B -CH2- is -Y A1 -NH-CO-O-CH2- and -Y A1 -O-CO-NH-CH2-, and preferably -Y A1 -NH-CO-O-CH2-.

[0030] In the formula (2), -Y A1 -Y B -ga, -Y A1 -(Y A2 ) b -(Y A3 ) c -(Y A4 ) d -(Y A5 ) e -(Y A6 ) f A structure represented by - is more preferred. Y A1 represents an unsubstituted alkylene group, and Y A2represents a methylene group substituted with at least one atom selected from the group consisting of a hydroxy group and a halogen atom, and Y A3 represents an unsubstituted alkylene group, and Y A4 represents an ester bond, an amide bond, or a urethane bond, and Y A5 represents an unsubstituted alkylene group, and Y A6 represents an oxygen atom or a sulfur atom, and b, c, d, e and f each independently represent 0 or 1.

[0031] Specific examples of the compound represented by formula (2) are shown below. [Table 1-1] [Table 1-2]

[0032] In polymer A having the structural unit represented by formula (1) and the structural unit represented by formula (2), the molar ratio of the structural unit represented by formula (1) to the structural unit represented by formula (2) is preferably 1:19 to 19:1, more preferably 1:1 to 19:1, and even more preferably 7:3 to 9:1.

[0033] The weight-average molecular weight of the polymer A having the structural unit represented by formula (1) contained in the surface layer of the electrophotographic photoreceptor of the present disclosure is preferably 16,000 or more and 100,000 or less, from the viewpoints of improving the dispersibility of the fluorine atom-containing resin particles and suppressing potential fluctuations.Moreover, the weight-average molecular weight of the polymer A having the structural unit represented by formula (1) is more preferably 18,000 or more and 80,000 or less.

[0034] The weight average molecular weight of the polymer A having the structural unit represented by the formula (1) can be measured and calculated by the following method. (Weight average molecular weight measured by GPC) The weight average molecular weight according to the present disclosure is measured by gel permeation chromatography (GPC) as follows. First, the sample is dissolved in tetrahydrofuran (THF) at room temperature for 24 hours. The resulting solution is then filtered through a solvent-resistant membrane filter "Maesholidisc" (manufactured by Tosoh Corporation) with a pore size of 0.2 μm to obtain a sample solution. The sample solution is adjusted so that the concentration of components soluble in THF is approximately 0.8 mass%. This sample solution is used for measurements under the following conditions. Apparatus: HLC8120 GPC (detector: RI) (Tosoh Corporation) Column: Shodex KF-801, 802, 803, 804, 805, 806, 807 (7 columns, manufactured by Showa Denko Co., Ltd.) Eluent: tetrahydrofuran (THF) ·Flow rate: 1.0ml / min Oven temperature: 40.0℃ Sample injection volume: 0.10 ml To calculate the molecular weight of a sample, a molecular weight calibration curve prepared using standard polystyrene resins (e.g., trade names "TSK Standard Polystyrene F-850, F-450, F-288, F-128, F-80, F-40, F-20, F-10, F-4, F-2, F-1, A-5000, A-2500, A-1000, A-500", manufactured by Tosoh Corporation) is used.

[0035] The content of the polymer A having the structural unit represented by the formula (1) in the surface layer relative to the fluorine atom-containing resin particles is preferably 2% by mass or more and 10% by mass or less, from the viewpoints of improving dispersibility and suppressing potential fluctuations.

[0036] Furthermore, the content of the polymer A having the structural unit represented by the formula (1) in the surface layer relative to the fluorine atom-containing resin particles is more preferably 4% by mass or more and 8% by mass or less, from the viewpoints of improving dispersibility and suppressing potential fluctuations.

[0037] <Fluorine atom-containing resin particles> The surface layer of the electrophotographic photoreceptor of the present disclosure contains fluorine atom-containing resin particles. Examples of resins contained in the fluorine atom-containing resin particles used in the present disclosure include the following: polytetrafluoroethylene resin, polychlorotrifluoroethylene resin, polytetrafluoroethylenepropylene resin, polyvinyl fluoride resin, polyvinylidene fluoride resin, and polydichlorodifluoroethylene resin.

[0038] It is also preferable to use particles containing a plurality of types of the above resins. Among the above, from the viewpoint of improving dispersibility, the fluorine atom-containing resin particles are more preferably polytetrafluoroethylene resin particles.

[0039] In cross-sectional observation of the surface layer, the fluorine atom-containing resin particles preferably have an arithmetic mean of the major axis of the primary particles (average primary particle size) measured from a secondary electron image taken with a scanning electron microscope of 150 nm or more and 300 nm or less, from the viewpoint of improving dispersibility and suppressing potential fluctuations. Furthermore, the fluorine atom-containing resin particles preferably have an average primary particle size of 180 nm or more and 250 nm or less.

[0040] The fluorine atom-containing resin particles preferably have an average circularity (average circularity) of 0.75 or more, calculated from the area and perimeter of primary particles measured from a secondary electron image taken by a scanning electron microscope.

[0041] In order to ensure that the measured values ​​of the average primary particle size and average circularity of the fluorine atom-containing resin particles contained in the surface layer of the electrophotographic photoreceptor of the present disclosure fall within the above ranges, fluorine atom-containing resin particles can be used such that the average primary particle size and average circularity values, as measured and calculated by the following methods, fall within the above ranges. (Method for measuring average primary particle size and average roundness) That is, in the examples of the present disclosure, the average particle size and average circularity of the fluorine atom-containing resin particles contained in the surface layer of the electrophotographic photosensitive member were measured using a field emission scanning electron microscope (FE-SEM) as follows. Fluorine-containing resin particles were attached to commercially available carbon conductive tape, and any fluorine-containing resin particles not attached to the conductive tape were removed with compressed air, followed by platinum deposition. The deposited fluorine-containing resin particles were observed using a Hitachi High-Technologies Corporation FE-SEM (S-4700). The measurement conditions for FE-SEM are as follows: Accelerating voltage: 2 kV WD: 5mm Magnification: 20,000 times Number of pixels: 1280 pixels vertically, 960 pixels horizontally (size of each pixel: 5 nm) From the obtained images, the Feret's diameter of 100 particles was determined using ImageJ (open source software from the National Institutes of Health (NIH)), and the average value was calculated to obtain the average particle size. Similarly, the area and circumference were determined, and the circularity was calculated from the following formula (α), and the average value was calculated to obtain the average circularity. Circularity = 4 × π × (area) ÷ (perimeter squared) Formula (α)

[0042] The fluorine atom-containing resin particles of the present disclosure may be used alone or in combination of two or more types.

[0043] The content of the fluorine atom-containing resin particles in the surface layer of the electrophotographic photoreceptor of the present disclosure is preferably 5% by mass or more and 40% by mass or less, more preferably 5% by mass or more and 15% by mass or less, and even more preferably 7% by mass or more and 12% by mass or less, based on the total mass of the surface layer.

[0044] <Triazine compounds> The surface layer of the electrophotographic photoreceptor of the present disclosure contains a cured product of a charge transporting compound and at least one triazine compound selected from the group consisting of guanamine compounds and melamine compounds. The triazine compound means a compound containing a triazine ring, and in the present invention, is a guanamine compound or a melamine compound.

[0045] The cured product of the charge transport compound (a) and the triazine compound (b) contained in the surface layer of the electrophotographic photoreceptor of the present invention is preferably a cured product obtained by reacting them in a molar ratio of b:a=1:3 to 1:300, and more preferably a molar ratio of b:a=1:5 to 1:100 from the following viewpoints: From the viewpoint of the abrasion resistance of the surface layer, it is more preferable that b:a=1:100 or less, and from the viewpoint of suppressing potential fluctuations due to repeated use, it is more preferable that b:a=1:5 or more.

[0046] In the present invention, the guanamine compound refers to a compound having a guanamine skeleton, such as acetoguanamine, benzoguanamine, formoguanamine, steroguanamine, spiroguanamine, and cyclohexylguanamine.

[0047] In the present invention, the guanamine compound is preferably a compound represented by the following formula (A) or a multimer thereof. [ka]

[0048] In formula (A), Rg 1 represents an alkyl group having 1 to 10 carbon atoms, a phenyl group having 6 to 10 carbon atoms, or an alicyclic hydrocarbon group having 4 to 10 carbon atoms. A phenyl group having 6 to 10 carbon atoms is particularly preferred. The alkyl group may be linear or branched. The alkyl group, phenyl group, and alicyclic hydrocarbon group may be unsubstituted or may have a substituent. Rg 1 When represents an alkyl group, the number of carbon atoms therein is preferably 1 or more and 8 or less, and more preferably 1 or more and 5 or less. Rg 1 When represents a phenyl group, the number of carbon atoms is preferably 6 or more and 8 or less. In addition, examples of the substituent of such a phenyl group include a methyl group, an ethyl group, and a propyl group. Rg 1When represents an alicyclic hydrocarbon group, the number of carbon atoms therein is preferably 5 or more and 8 or less. In addition, examples of the substituent of such an alicyclic hydrocarbon group include a methyl group, an ethyl group, and a propyl group.

[0049] Rg 2 ~Rg 5 are each independently a hydrogen atom, -CH2-OH or -CH2-O-Rg 6 Rg 6 represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms. Rg 6 When represents an alkyl group, the number of carbon atoms is preferably from 1 to 8, and more preferably from 1 to 6. Furthermore, examples of the substituent of such an alkyl group include a methyl group, an ethyl group, and a butyl group.

[0050] The compound represented by formula (A) can be synthesized by any known method, for example, a method using guanamine and formaldehyde.

[0051] The multimer of the compound represented by formula (A) is a compound obtained by polymerizing a plurality of compounds represented by formula (A). The degree of polymerization of the multimer is preferably 2 or more and 200 or less, more preferably 2 or more and 100 or less.

[0052] The compound represented by formula (A) may be used alone or in combination of two or more. In particular, it is preferable to use two or more compounds represented by formula (A) in combination or as a polymer, since the solubility in a solvent is improved.

[0053] Specific examples of the compound represented by formula (A) are shown below. The following specific examples are monomers, but may also be polymers thereof. In the following specific examples, "n-Bu" represents a normal butyl group.

[0054] [ka]

[0055] [ka]

[0056] [ka]

[0057] [ka]

[0058] In the present invention, the melamine compound means a compound having a melamine skeleton, and is preferably one selected from the compounds represented by general formula (B) and polymers thereof.

[0059] [ka]

[0060] Rm 1 ~Rm 6 are each independently a hydrogen atom, -CH2-OH, -CH2-O-Rm 7 , -O-Rm 7 Shows. Rm 7 represents an alkyl group having 1 to 5 carbon atoms. Such an alkyl group may be linear or branched. Preferred examples include a methyl group, an ethyl group, and a butyl group.

[0061] The compound represented by formula (B) can be synthesized by any known method, for example, a method using melamine and formaldehyde.

[0062] A multimer of the compound represented by formula (B) is a compound obtained by polymerizing a plurality of compounds represented by formula (B). The degree of polymerization of the multimer is preferably 2 or more and 200 or less, more preferably 2 or more and 100 or less. The compound represented by formula (B) may be used alone or in combination of two or more. In particular, it is preferable to use two or more compounds represented by formula (B) as a mixture or as a multimer, since this improves the solubility in a solvent.

[0063] Specific examples of the compound represented by formula (B) are shown below. The following specific examples are monomers, but may also be polymers thereof. In the following specific examples, "n-Bu" represents a normal butyl group, and "i-Bu" represents an isobutyl group.

[0064] [ka]

[0065] <Charge transport compound> The charge transport compound in the present disclosure is a compound having an organic group derived from a compound having charge transport capability and at least one polymerizable substituent (hereinafter also referred to as a "functional group").

[0066] Examples of functional groups that the charge transporting compound has include a hydroxy group (-OH), a methylol group (-CH2OH), a methoxy group (-OCH3), an amino group (-NH2), a thiol group (-SH), and a carboxyl group (-COOH). Among these, at least one functional group selected from a methylol group and a methoxy group is preferred.

[0067] In the organic group derived from a compound having charge transporting ability, the compound having charge transporting ability is preferably an arylamine derivative, such as a triphenylamine derivative or a tetraphenylbenzidine derivative.

[0068] Specific examples of the charge transporting compound include the following: [ka] [ka]

[0069] <Electrophotographic photoreceptor> The electrophotographic photoreceptor of the present disclosure has a surface layer. The electrophotographic photoreceptor of the present disclosure preferably has a support, a photosensitive layer, and optionally a protective layer. Of these, the photosensitive layer or the protective layer serves as the surface layer.

[0070] The surface layer of the electrophotographic photoreceptor of the present disclosure contains a cured product of a charge transporting compound and at least one triazine compound selected from the group consisting of guanamine compounds and melamine compounds, fluorine atom-containing resin particles, and polymer A having a structural unit represented by the above formula (1).

[0071] An example of the layer structure of the electrophotographic photoreceptor of the present disclosure, in which a protective layer serves as a surface layer, is shown in Figure 1. In Figure 1, an undercoat layer 102, a charge generation layer 103, a charge transport layer 104, and a protective layer 105 are laminated on a support 101. The photosensitive layer may be a laminated photosensitive layer having a charge generation layer and a charge transport layer, or may be a single-layer photosensitive layer containing a charge generation material and a charge transport material.

[0072] A method for producing the electrophotographic photoreceptor of the present disclosure includes preparing a coating liquid for each layer described below, coating the desired layers in order, and drying the coating liquid. Examples of methods for applying the coating liquid include dip coating, spray coating, inkjet coating, roll coating, die coating, blade coating, curtain coating, wire bar coating, and ring coating. Among these, dip coating is preferred from the viewpoints of efficiency and productivity.

[0073] The configuration of the electrophotographic photoreceptor of the present disclosure will be described below. <Support> The support of the electrophotographic photoreceptor is preferably conductive (conductive support). The support may be cylindrical, belt-like, or sheet-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. 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 these, an aluminum support using aluminum is preferred. 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.

[0074] <Conductive layer> A conductive layer may be provided on the support, which can conceal scratches and irregularities on the surface of the support and control light reflection on the surface of the support. The conductive layer preferably contains conductive particles and a resin.

[0075] 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, strontium titanate, 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 oxide particles as the conductive particles, and it is particularly preferable to use titanium oxide particles, tin oxide particles, or zinc oxide particles. When metal oxide particles are used as the conductive particles, the surfaces of the metal oxide particles may be treated with a silane coupling agent or the like, or the metal oxide particles may be doped with an element such as phosphorus or aluminum or an oxide thereof. The conductive particles may have a laminated structure including a core particle and a coating layer covering the core particle. Examples of the core particle include titanium oxide particles, barium sulfate particles, and zinc oxide particles. Examples of the coating layer include metal oxide particles such as tin oxide. 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.

[0076] 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.

[0077] The conductive layer can be formed by preparing a coating solution for the conductive layer containing the above-mentioned materials and solvent, forming this coating film on a support, and drying it. Examples of solvents used in the coating solution for the conductive layer 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.

[0078] The average thickness of the conductive layer is preferably 1 μm or more and 50 μm or less, and particularly preferably 3 μm or more and 40 μm or less.

[0079] <Undercoat layer> In the present disclosure, an undercoat layer may be provided on the support or the conductive layer. By providing an undercoat layer, adhesion between layers can be improved and a charge injection blocking function can be imparted.

[0080] 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. 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. 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 hydroxy group, an amino group, a carboxy group, a thiol group, a carboxylic acid anhydride group, and a carbon-carbon double bond group.

[0081] Furthermore, for the purpose of improving electrical properties, the undercoat layer may further contain an electron transport material, metal oxide particles, metal particles, a conductive polymer, etc. Among these, it is preferable to use an electron transport material or metal oxide particles. 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 oxide particles include particles of indium tin oxide, tin oxide, indium oxide, titanium oxide, strontium titanate, zinc oxide, and aluminum oxide. Silicon dioxide particles can also be used. Examples of metal particles include particles of gold, silver, and aluminum. The metal oxide particles contained in the undercoat layer may be surface-treated with a surface treatment agent such as a silane coupling agent.

[0082] The surface treatment of the metal oxide particles can be carried out by a common method, such as a dry method or a wet method. In the dry method, metal oxide particles are stirred in a mixer capable of high-speed stirring, such as a Henschel mixer, and an alcohol aqueous solution, organic solvent solution, or aqueous solution containing a surface treatment agent is added to the metal oxide particles to uniformly disperse them, followed by drying. In the wet method, metal oxide particles and a 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 solvent removal, it is preferable to further bake the mixture at 100°C or higher.

[0083] The undercoat layer may further contain additives, such as known materials such as metal particles such as aluminum particles, conductive material particles such as carbon black, charge transport materials, metal chelate compounds, and organometallic compounds.

[0084] The undercoat layer can be formed by preparing a coating solution for the undercoat layer containing the above-mentioned materials and solvent, forming a coating film on the support or the conductive layer, and drying and / or curing the coating film.

[0085] Examples of solvents 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 disclosure, it is preferable to use alcohol-based and ketone-based solvents.

[0086] 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.

[0087] 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.

[0088] <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) A multi-layer type photosensitive layer is a photosensitive layer having a charge generation layer containing a charge generation material and a charge transport layer containing a charge transport material. (2) A single-layer type photosensitive layer is a photosensitive layer containing both a charge generation material and a charge transport material.

[0089] (1) Laminated photosensitive layer The laminated photosensitive layer has a charge generating layer and a charge transport layer.

[0090] (1-1) Charge generation layer The charge generating layer preferably contains a charge generating material and a resin.

[0091] 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 or more and 85% by mass or less, and more preferably 60% by mass or more and 80% by mass or less, based on the total mass of the charge generating layer.

[0092] 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.

[0093] 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.

[0094] The charge generating layer can be formed by preparing a coating solution for the charge generating layer containing the above-mentioned materials and solvent, forming this coating film on the undercoat layer, and drying it. 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.

[0095] The average thickness of the charge generating layer is preferably from 0.1 μm to 1 μm, and more preferably from 0.15 μm to 0.4 μm.

[0096] (1-2) Charge transport layer The charge transport layer preferably contains a charge transport material and a resin.

[0097] Examples of the charge transport material include polycyclic aromatic compounds, heterocyclic compounds, hydrazone compounds, styryl compounds, enamine compounds, triarylamine compounds, and resins having groups derived from these materials. Among these, triarylamine 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.

[0098] 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.

[0099] The charge transport layer may also contain additives such as antioxidants, ultraviolet absorbers, plasticizers, leveling agents, etc. Specific examples of such additives include hindered phenol compounds, hindered amine compounds, sulfur compounds, phosphorus compounds, benzophenone compounds, siloxane-modified resins, silicone oils, polystyrene resin particles, polyethylene resin particles, and boron nitride particles.

[0100] 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 of this on the charge generation layer, and drying it.

[0101] Examples of the solvent used in the coating liquid include alcohol-based solvents, ketone-based solvents, ether-based solvents, ester-based solvents, and aromatic hydrocarbon-based solvents. Of these solvents, ether-based solvents and aromatic hydrocarbon-based solvents are preferred.

[0102] When the charge transport layer is a surface layer, the charge transport layer further contains a cured product of the above-mentioned charge transport compound and at least one triazine compound selected from the group consisting of guanamine compounds and melamine compounds, fluorine atom-containing resin particles, and polymer A having a structural unit represented by formula (1) above. When the charge transport layer is a surface layer, the materials described below in the <Surface Layer> section can be suitably used.

[0103] The average thickness of the charge transport layer is preferably from 5 μm to 50 μm, more preferably from 8 μm to 40 μm, and particularly preferably from 10 μm to 30 μm.

[0104] (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 on the undercoat layer, 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.

[0105] When the single-layer photosensitive layer is the surface layer, the single-layer photosensitive layer further contains a cured product of the above-mentioned charge transport compound and at least one compound selected from the group consisting of guanamine compounds and melamine compounds, fluorine atom-containing resin particles, and polymer A having a structural unit represented by formula (1). When the single-layer photosensitive layer is the surface layer, the materials described below in the <Surface Layer> section can be suitably used.

[0106] <Protective layer> In the present invention, a protective layer may be provided on the photosensitive layer. From the viewpoint of improving the durability of the electrophotographic photoreceptor, it is preferable to provide a protective layer. In the present invention, when a protective layer is provided, the protective layer becomes a surface layer of the electrophotographic photoreceptor.

[0107] <Surface layer> The surface layer of the electrophotographic photoreceptor of the present disclosure contains a cured product of the above-mentioned charge transport compound and at least one triazine compound selected from the group consisting of guanamine compounds and melamine compounds, fluorine atom-containing resin particles, and polymer A having a structural unit represented by formula (1) above.

[0108] The surface layer of the present invention may further contain a mixture of phenolic resin, melamine resin, urea resin, alkyd resin, etc. Furthermore, to improve strength, a compound having more functional groups per molecule, such as a spiroacetal guanamine resin (e.g., "CTU-Guanamine" (Ajinomoto Fine-Techno Co., Ltd.)), may be used.

[0109] In addition, the surface layer may be mixed with other thermosetting resins such as phenol resin, melamine resin, and benzoguanamine resin in order to effectively suppress oxidation caused by the discharge gas by adding them so as not to adsorb too much of the discharge gas.

[0110] It is preferable to add a surfactant to the surface layer, and the surfactant to be used is not particularly limited as long as it contains a compound containing at least one of a fluorine atom, an alkylene oxide structure, and a silicone structure. Compounds containing multiple such structures have high affinity and compatibility with charge transport compounds, improving the film-forming properties of the coating liquid for the surface layer and suppressing wrinkles and unevenness in the surface layer.

[0111] Furthermore, a resin that dissolves in alcohol may be added for the purpose of improving the surface layer's discharge gas resistance, mechanical strength, scratch resistance, particle dispersibility, viscosity control, torque reduction, wear control, and pot life extension. An alcohol-soluble resin refers to a resin that dissolves at 1% by mass or more in an alcohol having a carbon number of 5 or less. Examples of resins soluble in alcohol-based solvents include polyvinyl acetals such as polyvinyl butyral, polyvinyl formal, and partially acetalized polyvinyl acetals in which butyral is partially modified with formal, acetoacetal, or the like (for example, S-LEC B and K manufactured by Sekisui Chemical Co., Ltd.), polyamides, cellulose resins, and polyvinylphenols.

[0112] Furthermore, an antioxidant may be added to the surface layer. As the antioxidant, a hindered phenol-based or hindered amine-based antioxidant is preferable, and known antioxidants such as organic sulfur-based antioxidants, phosphite-based antioxidants, dithiocarbamate-based antioxidants, thiourea-based antioxidants, and benzimidazole-based antioxidants may also be used.

[0113] The surface layer may contain a curing catalyst to promote curing of the guanamine compound (compound represented by general formula (A)), the melamine compound (compound represented by general formula (B)), and the specific charge transport compound.

[0114] As the curing catalyst, an acid catalyst is preferably used. Examples of the acid catalyst include aliphatic carboxylic acids such as acetic acid, chloroacetic acid, trichloroacetic acid, trifluoroacetic acid, oxalic acid, maleic acid, malonic acid, and lactic acid; aromatic carboxylic acids such as benzoic acid, phthalic acid, terephthalic acid, and trimellitic acid; and aliphatic and aromatic sulfonic acids such as methanesulfonic acid, dodecylsulfonic acid, benzenesulfonic acid, dodecylbenzenesulfonic acid, and naphthalenesulfonic acid.

[0115] Of these, it is preferable to use a sulfur-containing material, and from the viewpoint of electrical properties, it is preferable to use at least one of organic sulfonic acid and its derivatives. Suitable examples of the organic sulfonic acid and / or its derivative include paratoluenesulfonic acid, dinonylnaphthalenesulfonic acid (DNNSA), dinonylnaphthalenedisulfonic acid (DNNDSA), dodecylbenzenesulfonic acid, and phenolsulfonic acid.

[0116] Commercially available catalysts include "NACURE2501" (toluenesulfonic acid dissociation), "NACURE2107" (p-toluenesulfonic acid dissociation), "NACURE2500" (p-toluenesulfonic acid dissociation), "NACURE2530" (p-toluenesulfonic acid dissociation), "NACURE2547" (p-toluenesulfonic acid dissociation), "NACURE2558" (p-toluenesulfonic acid dissociation), "NACUREXP-357" (p-toluenesulfonic acid dissociation), "NACUREXP-386" (p-toluenesulfonic acid dissociation), "NACUREXC-2211" (p-toluenesulfonic acid dissociation), "NACURE5225" (dodecylbenzenesulfonic acid dissociation), "NACURE5414" (dodecylbenzenesulfonic acid dissociation), and "NACURE" manufactured by King Industries. Examples include "E5528" (dodecylbenzenesulfonic acid dissociation), "NACURE5925" (dodecylbenzenesulfonic acid dissociation), "NACURE1323" (dinonylnaphthalenesulfonic acid dissociation), "NACURE1419" (dinonylnaphthalenesulfonic acid dissociation), "NACURE1557" (dinonylnaphthalenesulfonic acid dissociation), "NACUREX49-110" (dinonylnaphthalenesulfonic acid dissociation), "NACURE3525" (dinonylnaphthalenesulfonic acid dissociation), "NACUREXP-383" (dinonylnaphthalenesulfonic acid dissociation), "NACURE3327" (dinonylnaphthalenesulfonic acid dissociation), "NACURE4167" (phosphoric acid dissociation), "NACUREXP-297" (phosphoric acid dissociation), and "NACURE4575" (phosphoric acid dissociation). These catalysts may be used alone or in combination of two or more.

[0117] The amount of the catalyst to be added is preferably 0.1% by mass or more and 50% by mass or less, more preferably 10% by mass or more and 30% by mass or less, relative to the amount (solid content concentration in the coating liquid) of at least one triazine compound selected from the guanamine compound (compound represented by general formula (A)) and the melamine compound (compound represented by general formula (B)).

[0118] Examples of solvents for the surface layer coating liquid include single solvents or mixed solvents such as aromatic hydrocarbons such as toluene, xylene, and chlorobenzene; alcohols such as methanol, ethanol, propanol, butanol, cyclopentanol, and cyclohexanol; ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone; ethers such as tetrahydrofuran, diethyl ether, diisopropyl ether, and dioxane; and esters such as ethyl acetate, n-propyl acetate, n-butyl acetate, and ethyl lactate.

[0119] Examples of a dispersion method for dispersing solid components such as fluorine atom-containing resin particles in a surface layer coating liquid include dispersion methods using media dispersers such as a ball mill, a vibration ball mill, an attritor, a sand mill, or a horizontal sand mill, and medialess dispersers such as agitators, ultrasonic dispersers, roll mills, or high-pressure homogenizers. Further examples of the dispersion method include a collision method using a high-pressure homogenizer in which the dispersion liquid is dispersed by liquid-liquid collision or liquid-wall collision under high pressure, and a penetration method in which the dispersion is dispersed by penetrating a fine flow path under high pressure.

[0120] The surface layer can be formed by preparing a surface layer coating solution containing the above-mentioned materials, the charge transport compound described above, at least one triazine compound selected from the group consisting of guanamine compounds and melamine compounds, fluorine atom-containing resin particles, polymer A having a structural unit represented by formula (1), and a solvent, and forming this coating film on the undercoat layer, charge generation layer, or charge transport layer, and heating it at a temperature of 100°C or higher and 180°C or lower to cure (crosslink) it.

[0121] The thickness of the surface layer is set, for example, preferably in the range of 1 μm to 40 μm, more preferably in the range of 3 μm to 35 μm.

[0122] <Surface treatment of electrophotographic photoreceptors> In the present disclosure, the surface of the electrophotographic photosensitive member may be subjected to a surface treatment. By performing the surface treatment, the behavior of a cleaning means (cleaning blade) that comes into contact with the electrophotographic photosensitive member can be further stabilized. Examples of surface treatment methods include a method in which a mold having convex portions is pressed against the surface of the electrophotographic photosensitive member to transfer the shape, a method in which an uneven shape is imparted by mechanical polishing, or a method in which powder is collided with the surface of the electrophotographic photosensitive member to roughen the surface. In this way, by providing concave or convex portions on the surface layer of the electrophotographic photosensitive member, the behavior of a cleaning means that comes into contact with the electrophotographic photosensitive member can be further stabilized.

[0123] The recesses or protrusions may be formed over the entire surface of the electrophotographic photosensitive member, or may be formed on only a part of the surface of the electrophotographic photosensitive member. When the recesses or protrusions are formed on only a part of the surface of the electrophotographic photosensitive member, it is preferable that the recesses or protrusions are formed over at least the entire contact area with the cleaning means (cleaning blade).

[0124] When forming recesses, a mold having protrusions corresponding to the recesses is pressed against the surface of the electrophotographic photosensitive member to transfer the shape, thereby forming the recesses on the surface of the electrophotographic photosensitive member.

[0125] <Abrasive tools used for mechanical polishing> Mechanical polishing can be performed by known means. Generally, an abrasive tool is brought into contact with an electrophotographic photosensitive member, and one or both of them are moved relatively to polish the surface of the electrophotographic photosensitive member. The abrasive tool is a polishing member having a substrate and a layer in which abrasive grains are dispersed in a binder resin.

[0126] Examples of abrasive grains include particles of aluminum oxide, chromium oxide, diamond, iron oxide, cerium oxide, corundum, silica stone, silicon nitride, boron nitride, molybdenum carbide, silicon carbide, tungsten carbide, titanium carbide, and silicon oxide. The particle size of the abrasive grains is preferably 0.01 to 50 μm, and more preferably 1 to 15 μm. If the particle size of the abrasive grains is too small, the polishing power becomes weak, making it difficult to increase the F / C ratio of the outermost surface of the electrophotographic photosensitive member. These abrasive grains can be used alone or in combination of two or more types. When two or more types are mixed, the materials and particle sizes may be different or the same.

[0127] The binder resin used to disperse the abrasive grains in the polishing tool can be any of the well-known thermoplastic resins, thermosetting resins, reactive resins, electron beam curable resins, ultraviolet curable resins, visible light curable resins, and antifungal resins. Examples of thermoplastic resins include vinyl chloride resins, polyamide resins, polyester resins, polycarbonate resins, amino resins, styrene-butadiene copolymers, urethane elastomers, and polyamide-silicone resins. Examples of thermosetting resins include phenolic resins, phenoxy resins, epoxy resins, polyurethane resins, polyester resins, silicone resins, melamine resins, and alkyd resins. An isocyanate-based curing agent may also be added to the thermoplastic resin.

[0128] The thickness of the layer of the abrasive tool, in which abrasive grains are dispersed in a binder resin, is preferably 1 to 100 μm. If the layer is too thick, unevenness in the layer thickness is likely to occur, resulting in unevenness in the surface roughness of the object to be polished. On the other hand, if the layer is too thin, abrasive grains are likely to fall off.

[0129] The shape of the substrate of the abrasive tool is not particularly limited. In the examples of the present disclosure, a sheet-like substrate is used to efficiently abrade a cylindrical electrophotographic photoreceptor, but other shapes may also be used. (Hereinafter, the abrasive tool of the present disclosure will also be referred to as an abrasive sheet.) The material of the substrate of the abrasive tool is also not particularly limited. For example, the material of the sheet-like substrate may be paper, woven fabric, nonwoven fabric, or plastic film.

[0130] The abrasive tool can be obtained by coating a base material with a coating material in which the above-mentioned abrasive grains, binder resin, and a solvent capable of dissolving the binder resin are mixed and dispersed, followed by drying.

[0131] <Process cartridge, electrophotographic device> The electrophotographic photosensitive member of the present disclosure may be one of the components of a process cartridge or an electrophotographic apparatus. The process cartridge is characterized by integrally supporting the electrophotographic photosensitive member described above 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. The electrophotographic apparatus is characterized by having the electrophotographic photosensitive member described above, a charging means, an exposure means, a developing means, and a transfer means.

[0132] An example of the configuration of the process cartridge of the present invention is shown in FIG. 2. In FIG. 2, a cylindrical electrophotographic photosensitive member 1 is rotated in the direction of the arrow at a predetermined peripheral speed. The peripheral surface of the rotated electrophotographic photosensitive member 1 is uniformly charged to a predetermined positive or negative potential by charging means 2. Next, the charged peripheral surface of the electrophotographic photosensitive member 1 is exposed to exposure light (image exposure light) 3 output from exposure means (not shown) such as slit exposure or laser beam scanning exposure. In this way, an electrostatic latent image corresponding to a target image is sequentially formed on the peripheral surface of the electrophotographic photosensitive member 1. The voltage applied to the charging means (such as a charging roller) 2 may be a voltage in which an AC component is superimposed on a DC component, or a voltage consisting of only a DC component.

[0133] The electrostatic latent image formed on the peripheral surface of the electrophotographic photosensitive member 1 is developed into a toner image by the toner contained in the developer of the developing means 4. Next, the toner image formed and carried on the peripheral surface of the electrophotographic photosensitive member 1 is sequentially transferred onto a transfer material (paper, intermediate transfer member, etc.) 6 by a transfer bias from a transfer means (transfer roller, etc.) 5. The transfer material 6 is fed in synchronization with the rotation of the electrophotographic photosensitive member 1.

[0134] After the toner image is transferred, the surface of the electrophotographic photoreceptor 1 is subjected to a charge removal process by pre-exposure from a pre-exposure means 7, and then the surface is cleaned by removing the residual toner from the surface by a cleaning means 8, and the electrophotographic photoreceptor 1 is then repeatedly used for image formation. The pre-exposure means may be placed before or after the cleaning step, and is not necessarily required.

[0135] The electrophotographic photosensitive member 1 may be mounted in an electrophotographic apparatus such as a copying machine or a laser beam printer. In addition, a process cartridge 9 may be configured such that a plurality of components, such as the electrophotographic photosensitive member 1, charging means 2, developing means 4, pre-exposure means 7, and cleaning means 8, are housed in a container and integrally supported, and is detachably mounted on the main body of the electrophotographic apparatus.

[0136] In FIG. 2, an electrophotographic photosensitive member 1, charging means 2, developing means 4, pre-exposure means 7 and cleaning means 8 are integrally supported as a process cartridge 9 that is detachably mountable to the main body of the electrophotographic apparatus.

[0137] Next, an electrophotographic apparatus equipped with the electrophotographic photosensitive member of the present invention will be described. An example of the configuration of the electrophotographic apparatus of the present invention is shown in Figure 3. A yellow process cartridge 17, a magenta process cartridge 18, a cyan process cartridge 19, and a black process cartridge 20, each corresponding to a different color, are arranged side by side along an intermediate transfer body 10. The diameter, constituent materials, developer, charging method, and other means of the electrophotographic photosensitive member do not necessarily need to be the same for each color.

[0138] When the image formation operation begins, toner images of each color are sequentially superimposed on the intermediate transfer body 10 according to the image formation process described above. In parallel, transfer paper 11 is fed from paper feed tray 13 via paper feed path 12 and fed to secondary transfer means 14 in synchronization with the rotation of the intermediate transfer body. The toner image on the intermediate transfer body 10 is transferred to the transfer paper 11 by a transfer bias from secondary transfer means 14. The toner image transferred onto the transfer paper 11 is transported along paper feed path 12, fixed on the transfer paper by fixing means 15, and then discharged from paper discharge section 16.

[0139] The electrophotographic photoreceptor of the present disclosure can be used in laser beam printers, LED printers, copiers, facsimiles, and multifunction machines thereof. [Example]

[0140] The present disclosure will be described in more detail below using examples and comparative examples, but is not limited thereto. In the following description of the examples, "parts" are by mass unless otherwise specified.

[0141] <Synthesis of Polymer A Having Structural Unit Represented by Formula (1)> Polymer A (hereinafter, polymer A may be referred to as a "graft copolymer") having a structural unit represented by formula (1) in the present disclosure was synthesized as follows. The acrylate compound and macromonomer compound used in the synthesis examples below can be produced by referring to, for example, JP-A-2009-104145.

[0142] (Graft copolymer D-1) 54 parts of the compound represented by the following formula M-1, 75 parts of the macromonomer (number average molecular weight 6,000) represented by the following formula (2-1), 0.436 parts of 1,1'-azobis(1-acetoxy-1-phenylethane) (trade name: OTAZO-15, manufactured by Otsuka Chemical Co., Ltd.), and 338 parts of n-butyl acetate were mixed in a glass flask equipped with a stirrer, reflux condenser, nitrogen gas inlet tube, thermostatic bath, and thermometer at 20°C under a nitrogen atmosphere for 30 minutes, and then the reaction solution was heated to 85-90°C and reacted for 5 hours. The reaction was stopped by cooling with ice, and a precipitate was obtained by adding 1500 parts by mass of 2-propanol. This precipitate was washed with a mixed solvent of n-butyl acetate:2-propanol=1:5 and dried at a temperature of 80° C. under reduced pressure of 1325 Pa or less for 3 hours to obtain graft copolymer D-1. [ka]

[0143] [ka] [ka]

[0144] (Graft copolymer D-2) Graft copolymer D-2 was obtained in the same manner as graft copolymer D-1, except that 54 parts of the compound represented by formula M-1 above was changed to 42 parts of the compound represented by formula M-2 above.

[0145] (Graft copolymer D-3) Graft copolymer D-3 was obtained in the same manner as graft copolymer D-1, except that 54 parts of the compound represented by formula M-1 above was changed to 44 parts of the compound represented by formula M-3 above.

[0146] (Graft copolymer D-4) Graft copolymer D-4 was obtained in the same manner as graft copolymer D-1, except that 54 parts of the compound represented by formula M-1 above was changed to 52 parts of the compound represented by formula M-4 above.

[0147] (Graft copolymer D-5) Graft copolymer D-5 was obtained in the same manner as graft copolymer D-1, except that 54 parts of the compound represented by formula M-1 above was changed to 42 parts of the compound represented by formula M-5 above.

[0148] (Graft copolymer D-6) Graft copolymer D-6 was obtained in the same manner as graft copolymer D-1, except that 54 parts of the compound represented by formula M-1 above was changed to 47 parts of the compound represented by formula M-6 above.

[0149] (Graft copolymer D-7) Graft copolymer D-7 was obtained in the same manner as graft copolymer D-1, except that 54 parts of the compound represented by formula M-1 above was changed to 52 parts of the compound represented by formula M-7 above.

[0150] (Graft copolymer D-8) Graft copolymer D-8 was obtained in the same manner as graft copolymer D-1, except that 54 parts of the compound represented by formula M-1 above was changed to 55 parts of the compound represented by formula M-8 above.

[0151] (Graft copolymer D-9) Graft copolymer D-9 was obtained in the same manner as graft copolymer D-1, except that 54 parts of the compound represented by formula M-1 above was changed to 55 parts of the compound represented by formula M-9 above.

[0152] (Graft copolymer D-10) Graft copolymer D-10 was obtained in the same manner as graft copolymer D-1, except that 54 parts of the compound represented by formula M-1 above was changed to 55 parts of the compound represented by formula M-10 above.

[0153] (Graft copolymer D-11) Graft copolymer D-11 was obtained in the same manner as graft copolymer D-1, except that 54 parts of the compound represented by formula M-1 above was changed to 59 parts of the compound represented by formula M-11 above.

[0154] (Graft copolymer D-12) Graft copolymer D-12 was obtained in the same manner as graft copolymer D-1, except that 54 parts of the compound represented by formula M-1 above was changed to 37 parts of the compound represented by formula M-12 above.

[0155] (Graft copolymer D-13) Graft copolymer D-13 was obtained in the same manner as graft copolymer D-1, except that 54 parts of the compound represented by formula M-1 above was changed to 32 parts of the compound represented by formula M-13 above.

[0156] (Graft copolymer D-14) Graft copolymer D-14 was obtained in the same manner as graft copolymer D-1, except that the ingredients were changed to 27 parts of the compound represented by formula M-1 above, 300 parts of the macromonomer (number average molecular weight 6,000) represented by formula (2-1) above, and 0.390 parts of 1,1'-azobis(1-acetoxy-1-phenylethane) (trade name: OTAZO-15, manufactured by Otsuka Chemical Co., Ltd.).

[0157] (Graft copolymer D-15) Graft copolymer D-15 was obtained in the same manner as graft copolymer D-1, except that the ingredients were changed to 54 parts of the compound represented by formula M-1 above, 32 parts of the macromonomer represented by formula (2-1) above (number average molecular weight 6,000), and 0.408 parts of 1,1'-azobis(1-acetoxy-1-phenylethane) (trade name: OTAZO-15, manufactured by Otsuka Chemical Co., Ltd.).

[0158] (Graft copolymer D-16) Graft copolymer D-16 was obtained in the same manner as graft copolymer D-1, except that the ingredients were changed to 21 parts of the compound represented by formula M-1 above, 360 parts of the macromonomer (number average molecular weight 6,000) represented by formula (2-1) above, and 0.390 parts of 1,1'-azobis(1-acetoxy-1-phenylethane) (trade name: OTAZO-15, manufactured by Otsuka Chemical Co., Ltd.).

[0159] (Graft copolymer D-17) Graft copolymer D-17 was obtained in the same manner as graft copolymer D-1, except that the ingredients were changed to 54 parts of the compound represented by formula M-1 above, 29 parts of the macromonomer represented by formula (2-1) (number average molecular weight 6,000), and 0.390 parts of 1,1'-azobis(1-acetoxy-1-phenylethane) (trade name: OTAZO-15, manufactured by Otsuka Chemical Co., Ltd.).

[0160] (Graft copolymer D-18) Graft copolymer D-18 was obtained in the same manner as graft copolymer D-1, except that 54 parts of the compound represented by formula M-1 above was changed to 59 parts of the compound represented by formula M-14 above.

[0161] (Graft copolymer D-19) Graft copolymer D-19 was obtained in the same manner as graft copolymer D-1, except that 54 parts of the compound represented by formula M-1 above was changed to 60 parts of the compound represented by formula M-15 above.

[0162] (Graft copolymer D-20) Graft copolymer D-20 was obtained in the same manner as graft copolymer D-1, except that 54 parts of the compound represented by formula M-1 above was changed to 53 parts of the compound represented by formula M-16 above.

[0163] (Graft copolymer D-21) Graft copolymer D-21 was obtained in the same manner as graft copolymer D-1, except that 54 parts of the compound represented by formula M-1 above was changed to 42 parts of the compound represented by formula M-17 above.

[0164] The resulting graft copolymers D-1 to D-21 were subjected to GPC measurement by the method described above, and the weight average molecular weights were calculated. The results are shown in Tables 2 to 4.

[0165] [Table 2]

[0166] [Table 3]

[0167] [Table 4]

[0168] [Example 1] <Production of electrophotographic photoreceptors> A cylindrical aluminum cylinder (JIS-A3003, aluminum alloy, outer diameter 30.6 mm, length 370 mm) was used as the support (conductive support). Ultrasonic cleaning was performed in a cleaning solution containing pure water and detergent (product name: Chemicol CT, manufactured by Tokiwa Chemical Co., Ltd.), followed by rinsing off the cleaning solution, followed by further ultrasonic cleaning in pure water to prepare a degreased support.

[0169] Zinc oxide particles (specific surface area: 19 m 2 / g, powder resistance: 4.7×10 6 100 parts of the sol-gel (Ω·cm) was mixed with 500 parts of toluene and stirred, to which 0.8 parts of a silane coupling agent (compound name: N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, product name: KBM602, manufactured by Shin-Etsu Chemical Co., Ltd.) was added and stirred for 6 hours. Thereafter, the toluene was 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 A. Next, 15 parts of butyral (trade name: BM-1, manufactured by Sekisui Chemical Co., Ltd.) as a polyol and 15 parts of blocked isocyanate (trade name: Duranate TPA-B80E, nonvolatile content 80% by mass, manufactured by Asahi Kasei Chemicals Corp.) were dissolved in a mixed solvent of 73.5 parts of methyl ethyl ketone and 73.5 parts of 1-butanol. To this solution, 80.8 parts of surface-treated zinc oxide particles A and 0.81 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 the dispersion process, 0.01 parts of silicone oil (trade name: SH28PA, manufactured by Toray Dow Corning Co., Ltd. (formerly Toray Dow Corning Silicones Co., Ltd.)) and 5.6 parts of cross-linked polymethyl methacrylate (PMMA) particles (trade name: Techpolymer SSX-103, manufactured by Sekisui Plastics Co., Ltd., average primary particle size: 3 μm) were added and stirred to prepare a coating solution for the undercoat layer. The obtained coating liquid for undercoat layer was dip-coated onto the support to form a coating film, and the coating film was dried at 160° C. for 30 minutes to form an undercoat layer with a thickness of 20 μm.

[0170] Next, 4 parts of hydroxygallium phthalocyanine crystals (charge-generating material) with strong peaks at Bragg angles 2θ±0.2° (7.3°, 16.0°, 24.9°, and 28.0°) in CuKα characteristic X-ray diffraction and 2 parts of vinyl chloride-vinyl acetate copolymer resin (VMCH, manufactured by Nippon Unicar Co., Ltd.) as a binder resin were dissolved in 100 parts of n-vinyl acetate. The solution was then dispersed in a sand mill using 1 mm diameter glass beads in an atmosphere of 23±3°C for 1 hour, and after dispersion, 100 parts of methyl ethyl ketone was added to prepare a coating solution for the charge-generating layer. This charge generating layer coating liquid was dip coated onto the undercoat layer, and the resulting coating was dried at 70° C. for 10 minutes to form a charge generating layer having a thickness of 0.20 μm.

[0171] A coating solution for the charge transport layer was prepared by dissolving 100 parts of N,N'-diphenyl-N,N'-bis(3-methylphenyl)-[1,1']biphenyl-4,4'-diamine and 100 parts of bisphenol Z-type polycarbonate resin (trade name: Iupilon Z400, manufactured by Mitsubishi Engineering Plastics Corporation) in a mixed solvent of 272 parts of o-xylene, 256 parts of methyl benzoate, and 272 parts of dimethoxymethane. This charge transport layer coating liquid was dip coated onto the charge generating layer to form a coating film, and the resulting coating film was dried at 120° C. for 50 minutes to form a charge transport layer with a thickness of 20 μm.

[0172] [Surface layer 1] A dispersant solution was prepared by dissolving 0.8 parts of the above-mentioned graft copolymer D-1 in 80 parts of tetrahydrofuran as a solvent. To the resulting dispersant solution, 14 parts of polytetrafluoroethylene resin particles (average primary particle size 210 nm, average circularity 0.85) were added, and the mixture was passed through a high-pressure disperser (product name: Microfluidizer M-110EH, manufactured by Microfluidics, Inc., USA) to obtain a polytetrafluoroethylene resin particle dispersion. To the obtained polytetrafluoroethylene resin particle dispersion, 161 parts of the charge transporting compound represented by the above formula C-26, 5 parts of the guanamine compound represented by the above formula A-1, 2.6 parts of 3,5-di-t-butyl-4-hydroxytoluene (BHT), 0.4 parts of dodecylbenzenesulfonic acid, 130 parts of cyclopentanone, and 90 parts of cyclopentanol were added. Then, the mixture was filtered with a Polyflon filter (trade name: PF-040, manufactured by Advantec Toyo Co., Ltd.) to prepare surface layer coating solution 1. The charge transport layer was dip-coated with this surface layer coating solution 1 to form a coating film, which was then cured (crosslinked) in a heat dryer at 150°C for 60 minutes to form a surface layer. The thickness of the resulting surface layer was 6 μm. In this manner, an electrophotographic photoreceptor 1 having a support and a surface layer was prepared.

[0173] <Evaluation of Electrophotographic Photoreceptors> [Image evaluation] The electrophotographic photoreceptor 1 was mounted on a copying machine, imagePRESS C910 (product name), manufactured by Canon Inc., and image evaluation was carried out. In detail, the above-mentioned evaluation device was placed in an environment of a temperature of 23°C and a relative humidity of 50%RH, and the prepared electrophotographic photosensitive member was attached to a magenta process cartridge, which was then attached to the station of the magenta process cartridge, and evaluation was performed. Image evaluation was performed using the above-mentioned evaluation device. A halftone image was printed on A4-size glossy paper, and the number of image defects due to poor dispersion, i.e., black spots, contained in the area of ​​one circumference of the electrophotographic photoreceptor in the printed image was visually evaluated and the results are shown in Table 6. The size of each black spot that occurred was also measured, and the largest size measured was also shown in Table 6. The area of ​​one circumference of the electrophotographic photosensitive member is a rectangular region whose length is 297 mm, which is the long side length of an A4 sheet of paper, and whose width is 94.2 mm, which is one circumference of the electrophotographic photosensitive member. The results of the evaluation are shown in Table 6. In the present disclosure, the fewer the number of black dots, the better, and the more the effects of the present disclosure are obtained.

[0174] [Electrical property evaluation] The electrophotographic photoreceptor 1 was mounted on a modified copy machine, imagePRESS C910 (product name) manufactured by Canon Inc., and the electrical characteristics were evaluated. The charging means of this modified machine is a charging means that applies a voltage in which an AC voltage is superimposed on a DC voltage to a roller-type contact charging member (charging roller), and the exposure means is an exposure means of a laser image exposure method (wavelength 680 nm). In detail, the above-mentioned evaluation device was placed in an environment of a temperature of 23°C and a relative humidity of 50%RH, and the prepared electrophotographic photosensitive member was attached to a magenta process cartridge, which was then attached to the station of the magenta process cartridge, and evaluation was performed. The charging conditions were adjusted so that the charging potential was −900V and the exposure potential was −350V, and the charging potential and the exposure amount of the exposure means were adjusted. The surface potential of the electrophotographic photosensitive member was measured by removing the developing cartridge from the evaluation device and inserting a potential measuring device therein. The potential measuring device is configured by disposing a potential measuring probe (product name: model 6000B-8, manufactured by Trek Japan Co., Ltd.) at the development position of the development cartridge. The position of the potential measuring probe relative to the electrophotographic photosensitive member was set to the center of the electrophotographic photosensitive member in the generatrix direction, with a gap of 3 mm from the surface of the electrophotographic photosensitive member. Furthermore, the potential at the center of the electrophotographic photosensitive member was measured using a surface potential meter (trade name: Model 344, manufactured by Trek Japan Co., Ltd.).

[0175] Under the above evaluation conditions, the photoreceptor was repeatedly used by passing 10,000 sheets of paper through it. In a station equipped with an electrophotographic photosensitive member, a monochromatic character image with a printing rate of 1% was repeatedly formed on 10,000 sheets of A4 size 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 for 5 minutes, and the developing cartridge was then replaced with a potential measuring device, and the light area potential (Vlb) after repeated use was measured. The difference from the initial light area potential (Vla) was evaluated as the light area potential fluctuation (ΔVl = |Vlb| - |Vla|). The results are shown in Table 6. In the present disclosure, the smaller the change in bright area potential, the better, and the more the effects of the present disclosure can be obtained.

[0176] [Examples 2 to 13] Electrophotographic photoreceptors 2 to 13 were produced and evaluated in the same manner as in Example 1, except that in forming the surface layer of electrophotographic photoreceptor 1, graft copolymer D-1 was changed to the graft copolymer shown in Table 5.

[0177] [Example 14] An electrophotographic photoreceptor 14 was produced and evaluated in the same manner as in Example 1, except that in forming the surface layer of the electrophotographic photoreceptor 1, the charge transporting compound represented by the above formula C-26 was changed to the charge transporting compound represented by the above formula C-4.

[0178] [Example 15] An electrophotographic photoreceptor 15 was produced and evaluated in the same manner as in Example 1, except that in forming the surface layer of the electrophotographic photoreceptor 1, 161 parts of the charge transport compound represented by the above formula C-26 was changed to 85 parts of the charge transport compound represented by the above formula C-4 and 76 parts of the charge transport compound represented by the above formula C-10.

[0179] [Example 16] An electrophotographic photoreceptor 16 was prepared and evaluated in the same manner as in Example 1, except that in forming the surface layer of the electrophotographic photoreceptor 1, 5 parts of the guanamine compound represented by the above formula A-1 was changed to 0.62 parts.

[0180] [Example 17] An electrophotographic photoreceptor 17 was produced and evaluated in the same manner as in Example 1, except that in forming the surface layer of the electrophotographic photoreceptor 1, 5 parts of the guanamine compound represented by the above formula A-1 was changed to 12 parts.

[0181] [Example 18] An electrophotographic photoreceptor 18 was prepared and evaluated in the same manner as in Example 1, except that in forming the surface layer of the electrophotographic photoreceptor 1, 5 parts of the guanamine compound represented by the above formula A-1 was changed to 0.2 parts.

[0182] [Example 19] An electrophotographic photoreceptor 19 was produced and evaluated in the same manner as in Example 1, except that in forming the surface layer of the electrophotographic photoreceptor 1, 5 parts of the guanamine compound represented by the above formula A-1 was changed to 21 parts.

[0183] [Example 20] An electrophotographic photoreceptor 20 was produced and evaluated in the same manner as in Example 1, except that in forming the surface layer of the electrophotographic photoreceptor 1, 5 parts of the guanamine compound represented by the above formula A-1 was replaced with a melamine compound represented by the above formula B-8.

[0184] [Examples 21 to 24] Electrophotographic photoreceptors 20 to 24 were produced and evaluated in the same manner as in Example 1, except that in forming the surface layer of electrophotographic photoreceptor 1, graft copolymer D-1 was changed to the graft copolymer shown in Table 5.

[0185] [Example 25] An electrophotographic photoreceptor 25 was produced and evaluated in the same manner as in Example 1, except that in forming the surface layer of the electrophotographic photoreceptor 1, the polytetrafluoroethylene resin particles (average primary particle size 210 nm, average circularity 0.85) were changed to polytetrafluoroethylene resin particles (average primary particle size 150 nm, average circularity 0.82).

[0186] [Example 26] An electrophotographic photoreceptor 26 was produced and evaluated in the same manner as in Example 1, except that in forming the surface layer of the electrophotographic photoreceptor 1, the polytetrafluoroethylene resin particles (average primary particle size 210 nm, average circularity 0.85) were changed to polytetrafluoroethylene resin particles (average primary particle size 300 nm, average circularity 0.79).

[0187] [Comparative Examples 1 to 4] Comparative electrophotographic photoreceptors 1 to 4 were produced and evaluated in the same manner as in Example 1, except that in forming the surface layer of electrophotographic photoreceptor 1, graft copolymer D-1 was changed to the graft copolymer shown in Table 5.

[0188] [Table 5]

[0189] [Table 6]

[0190] [Wear resistance evaluation] The electrophotographic photoreceptors 1, 16, 18 and 20 were mounted on a copying machine, imagePRESS C910 (product name), manufactured by Canon Inc., and the abrasion resistance was evaluated for each. In detail, the above-mentioned evaluation device was placed in an environment of a temperature of 23°C and a relative humidity of 50%RH, and the prepared electrophotographic photosensitive member was attached to a magenta process cartridge, which was then attached to the station of the magenta process cartridge, and evaluation was performed. To evaluate abrasion resistance, a durability test was conducted using A4-sized plain paper, in which 100,000 halftone images with a print rate of 3% were printed. The difference in the thickness of the surface layer before and after the durability test was evaluated as the amount of abrasion, and the results are shown in Table 7.

[0191] [Table 7] [Explanation of symbols]

[0192] 101 Base 102 Undercoat layer 103 Charge generation layer 104 Charge transport layer 105 Surface layer 1. Electrophotographic photoreceptor 2. Charging means 3 Exposure light (image exposure light) 4. Developing methods 5 Transfer Method 6 Transfer material 7 Pre-exposure means 8 Cleaning Method 9 Process cartridge 10 Intermediate transfer body 11 Transfer paper 12 Paper feed path 13 Paper tray 14 Secondary transfer means 15 Fixation Method 16 Paper output section 17 Yellow process cartridge 18 Magenta process cartridge 19 Cyan process cartridge 20 Black process cartridge

Claims

1. An electrophotographic photoreceptor having a surface layer, The surface layer is a cured product of a charge transporting compound and at least one triazine compound selected from the group consisting of guanamine compounds and melamine compounds; fluorine atom-containing resin particles; A polymer A having a structural unit represented by the following formula (1) and a structural unit represented by the following formula (2), containing An electrophotographic photoreceptor characterized by the above-mentioned. 【Chemistry 1】 (In formula (1), R １１ represents a hydrogen atom or a methyl group, R １２ represents a single bond, a methylene group, or an ethylene group, n is an integer of 1 or more, Rf １ each independently represents a perfluoroalkylene group having from 1 to 5 carbon atoms or a perfluoroalkylidene group having from 1 to 5 carbon atoms, Rf ２ represents a perfluoroalkyl group having 1 to 5 carbon atoms. 【Chemistry 2】 (In formula (2), Y A1 represents an unsubstituted alkylene group; Y B represents an unsubstituted alkylene group, an alkylene group substituted with a halogen atom, an alkylene group substituted with a hydroxy group, an ester bond (—COO—), an amide bond (—NHCO—), a urethane bond (—NHCOO—), or a divalent linking group derived by combining one or more selected from these groups and bonds with —O— or —S—, or a single bond; Z A represents a structure represented by the following formula (2A): R 21 represents a hydrogen atom or a methyl group; R 22 represents a methyl group; m is an integer of 25 or more and 150 or less. 【Transformation 3】 (In formula (2A), Z A1 represents a methyl group.)

2. In the formula (1), n ​​Rf １ , and Rf ２ 2. The electrophotographic photoreceptor according to claim 1, wherein the total number of carbon atoms contained in is 5 or more and 8 or less.

3. 3. The electrophotographic photoreceptor according to claim 1, wherein n in formula (1) is an integer of 2 or less.

4. Rf in the formula (1) １ is a perfluoroalkylene group having 2 to 4 carbon atoms or a perfluoroalkylidene group having 2 to 4 carbon atoms, and Rf ２ 4. The electrophotographic photoreceptor according to claim 1, wherein is a perfluoroalkyl group having from 2 to 4 carbon atoms.

5. Rf in the formula (1) ２ 5. The electrophotographic photoreceptor according to claim 1, wherein is a perfluoroalkyl group having 3 or less carbon atoms.

6. The surface layer is a charge transporting compound having at least one functional group selected from a methylol group and a methoxy group; The triazine compound; Contains a cured product of The electrophotographic photoreceptor according to any one of claims 1 to 5.

7. The electrophotographic photoreceptor according to any one of claims 1 to 6, wherein the cured product is obtained by reacting the charge transporting compound (a) with the triazine compound (b) in a molar ratio of b:a = 1:5 to 1:

100.

8. the fluorine atom-containing resin particles are polytetrafluoroethylene resin particles, In cross-sectional observation of the surface layer, the arithmetic mean of the major axis of the primary particles measured from a secondary electron image of the polytetrafluoroethylene resin particles under a scanning electron microscope is 150 nm or more and 300 nm or less. The electrophotographic photoreceptor according to any one of claims 1 to 7.

9. 9. The electrophotographic photoreceptor according to claim 1, wherein the content of the fluorine atom-containing resin particles in the surface layer is 5% by mass or more and 40% by mass or less with respect to the total mass of the surface layer.

10. 9. The electrophotographic photoreceptor according to claim 1, wherein the content of the fluorine atom-containing resin particles in the surface layer is 5% by mass or more and 15% by mass or less with respect to the total mass of the surface layer.

11. 11. A process cartridge which 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, a discharging 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 photosensitive member according to claim 1, a charging unit, an exposure unit, a developing unit, and a transfer unit.

13. A method for manufacturing an electrophotographic photoreceptor having a surface layer, comprising: The production method includes a step of preparing a surface layer coating liquid containing a charge transporting compound, at least one triazine compound selected from the group consisting of guanamine compounds and melamine compounds, a polymer A having a structural unit represented by the following formula (1) and a structural unit represented by the following formula (2), and fluorine atom-containing resin particles; forming a coating film of the surface layer coating liquid, and drying and / or curing the coating film to form the surface layer; 10. A method for producing an electrophotographic photosensitive member, comprising: 【Chemistry 4】 (In formula (1), R １１ represents a hydrogen atom or a methyl group, R １２ represents a single bond, a methylene group, or an ethylene group, n is an integer of 1 or more, Rf １ are each independently, a perfluoroalkylene group having 1 or more and 5 or less carbon atoms, or represents a perfluoroalkylidene group having 1 to 5 carbon atoms, Rf ２ represents a perfluoroalkyl group having 1 or more and 5 or less carbon atoms. 【Transformation 5】 (In formula (2), Y A1 represents an unsubstituted alkylene group; Y B represents an unsubstituted alkylene group, an alkylene group substituted with a halogen atom, an alkylene group substituted with a hydroxy group, an ester bond (—COO—), an amide bond (—NHCO—), a urethane bond (—NHCOO—), or a divalent linking group derived by combining one or more selected from these groups and bonds with —O— or —S—, or a single bond; Z A represents a structure represented by the following formula (2A): R 21 represents a hydrogen atom or a methyl group; R 22 represents a methyl group; m is an integer of 25 or more and 150 or less. 【Transformation 6】 (In formula (2A), Z A1 represents a methyl group.)

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