Electrophotographic photosensitive member, process cartridge, and electrophotographic apparatus

Abstract

The invention relates to an electrophotographic photosensitive member, a process cartridge, and an electrophotographic apparatus. The electrophotographic photosensitive member includes a support body, an undercoat layer directly formed on the support body, in which when an ionization potential of the undercoat layer is represented by IPu, IPu is 6.0 eV or more, when the ionization potential of the support body is represented by IPs, IPs is lower than IPu, the undercoat layer contains a compound (alpha), when an ionization potential of the compound (alpha) is represented by IPalpha, IPu is 6.0 eV or more, and the photosensitive layer is formed on the undercoat layer. IPalpha is 5.0 eV or more and 5.4 eV or less, and IPs and IPalpha satisfy the following relational expression (1): IPs > = IPalpha-1. 0 (1).

Description

Technical Field

[0001] The present disclosure relates to an electrophotographic photosensitive member, and a process cartridge and an electrophotographic apparatus each having the electrophotographic photosensitive member. Background Art

[0002] In recent years, images output from electrophotographic apparatuses are required to have higher image quality and higher stability.

[0003] As technologies for solving such problems, there are Japanese Patent Application Laid-Open No. 2020-101652, Japanese Patent Application Laid-Open No. 2020-46640, and Japanese Patent Application Laid-Open No. 2023-115641.

[0004] In Japanese Patent Application Laid-Open No. 2020-101652, an electrophotographic photosensitive member containing a specific perinone compound and an amine compound having an ionization potential of 5.4 eV or more and 5.9 eV or less in the atmosphere is described.

[0005] In Japanese Patent Application Laid-Open No. 2020-46640, an electrophotographic photosensitive member having an undercoat layer containing a specific pyrenone compound and polyurethane is described.

[0006] In Japanese Patent Application Laid-Open No. 2023-115641, there is described an electrophotographic photosensitive member which contains a triarylamine compound having a reactive group, a curing agent, and an electron transporting material in an undercoat layer and contains a butyral resin in a specific ratio.

[0007] According to studies by the present inventors, it has been found that, in the electrophotographic photosensitive members described in Japanese Patent Application Laid-Open No. 2020-101652, Japanese Patent Application Laid-Open No. 2020-46640, and Japanese Patent Application Laid-Open No. 2023-115641, the residual potential is high and there is room for improvement in terms of fluctuation in light area potential.

[0008] In addition, it has been found that, in some electrophotographic photosensitive members described in Japanese Patent Application Laid-Open No. 2023-115641, the residual potential is relatively small, but in some cases, the fluctuation in the light-area potential becomes relatively large. Summary of the invention

[0009] An object of the present disclosure is to provide an electrophotographic photosensitive member having a low residual potential and small fluctuation in light-area potential.

[0010] The present invention discloses an electrophotographic photosensitive member including a support, an undercoat layer formed directly on the support, and a photosensitive layer formed on the undercoat layer, wherein

[0011] When the ionization potential of the undercoat layer is represented by I Pu, I Pu is 6.0 eV or more,

[0012] When the ionization potential of the support is represented by IPs, IPs is lower than I Pu,

[0013] The primer layer comprises a compound (α),

[0014] When the ionization potential of the compound (α) is represented by IPα, IPα is 5.0 eV or more and 5.4 eV or less, and

[0015] IPs and IPα satisfy the following relation expression (1):

[0016] IPs ≥ IPα - 1.0 (1).

[0017] Further features of the present disclosure will become apparent from the following description of exemplary embodiments with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A diagram showing one example of a schematic configuration of an electrophotographic apparatus having a process cartridge provided with an electrophotographic photosensitive member. DETAILED DESCRIPTION

[0019] Embodiments of the present disclosure will now be described in detail according to the accompanying drawings.

[0020] According to the research of the present inventors, it has been found that in the techniques described in Japanese Patent Application Laid-Open No. 2020-101652, Japanese Patent Application Laid-Open No. 2020-46640, and Japanese Patent Application Laid-Open No. 2023-115641, the injection of holes from the support to the undercoat layer is small. When electrons are retained in the undercoat layer, it is difficult for the electrons to be eliminated. Therefore, the residual potential becomes high, and in some cases, the fluctuation of the bright area potential becomes large.

[0021] In addition, it has been found that, in some photosensitive members described in Japanese Patent Application Laid-Open No. 2023-115641, the residual potential is relatively low, but in some cases, the fluctuation in the light-area potential becomes large.

[0022] In order to solve this technical problem, the present inventors have studied the injection of holes from the support into the undercoat layer.

[0023] As a result of the above-mentioned studies, the present inventors have found that the above-mentioned technical problems can be solved by an electrophotographic photosensitive member having the following configuration.

[0024] Specifically, the present disclosure provides an electrophotographic photosensitive member including a support, an undercoat layer directly formed on the support, and a photosensitive layer formed on the undercoat layer, wherein

[0025] When the ionization potential of the undercoat layer is represented by I Pu, I Pu is 6.0 eV or more,

[0026] When the ionization potential of the support is represented by IPs, IPs is lower than I Pu,

[0027] The primer layer comprises a compound (α),

[0028] When the ionization potential of the compound (α) is represented by IPα, IPα is 5.0 eV or more and 5.4 eV or less, and

[0029] IPs and IPα satisfy the following relation expression (1):

[0030] IPs ≥ IPα - 1.0 (1).

[0031] The present inventors presume that the mechanism by which the above-mentioned technical problem can be solved by the above-mentioned configuration of the present disclosure is as follows.

[0032] In the primer layer formed directly on the support, the electron transport compound and the large ionization potential are included. Due to the characteristics of the primer layer, the injection of holes from the support to the primer layer is small, and the electrons in the primer layer are completely removed by the transport of electrons. Therefore, when electrons are retained in the primer layer, it is difficult for the electrons to be removed from the primer layer, and the residual potential tends to increase easily.

[0033] In the conventional technology, it is presumed that since the electrons retained in the undercoat layer are difficult to be removed, the residual potential becomes high and the fluctuation of the light-area potential becomes large.

[0034] In addition, when the ionization potential of the compound included in the undercoat layer is too small, the residual potential can be reduced, but the balance with the dark area potential is lost, resulting in increased fluctuation of the light area potential.

[0035] In the present disclosure, when the ionization potential of the undercoat layer is represented by I Pu, I Pu is 6.0 eV or more, and when the ionization potential of the support is represented by IPs, IPs is lower than I Pu, and when the ionization potential of the compound (α) is represented by IPα, IPα is 5.0 eV or more and 5.4 eV or less, and

[0036] IPs and IPα satisfy IPs≥IPα-1.0(1); and it is believed that this promotes proper injection of holes from the support into the undercoat layer, makes it easier to remove electrons that tend to remain in the undercoat layer, reduces the residual potential, and further suppresses fluctuations in the bright area potential.

[0037] <Measurement of ionization potential>

[0038] The ionization potential is usually obtained by photoemission yield spectroscopy in Air (PYSA) or photoelectron yield spectroscopy (PYS). It is known that the values ​​obtained by the above two methods are different depending on the difference in the amount of water on the sample surface, etc. The ionization potential in the present disclosure is obtained by photoelectron yield spectroscopy (PYS). The measurement is carried out in a nitrogen atmosphere, and the ionization potential can be obtained from the intersection of the slope of the line in the coordinate system in which the irradiated ultraviolet light is taken on the horizontal axis and the square root of the photoelectron emission amount is taken on the vertical axis and the background.

[0039] [Electrophotographic photosensitive member]

[0040] The electrophotographic photosensitive member according to the present disclosure includes a support, an undercoat layer directly formed on the support, and a photosensitive layer formed on the undercoat layer. The support is preferably cylindrical. The photosensitive layer preferably includes a charge generating layer formed on the undercoat layer and a hole transport layer formed on the charge generating layer.

[0041] The manufacturing method of the electrophotographic photosensitive member of the present disclosure includes a method of preparing a coating liquid for each layer to be described later, forming a coating film of the coating liquid, and drying and / or curing the coating film. In this case, examples of the coating method of the coating liquid (method of forming a coating film) include blade coating, curtain coating, wire rod coating, and ring coating. Among these methods, dip coating is preferred from the viewpoint of efficiency and productivity.

[0042] The support and the layers will be described below.

[0043] <Support>

[0044] The support is preferably a cylindrical support. The surface of the support is preferably formed of Al and / or Al alloy. In addition, the surface of the support may be subjected to hot water treatment, sandblasting or cutting treatment.

[0045] In order to more effectively obtain the effects of the present disclosure, the ionization potential IPs of the support surface is preferably 5.6 eV or more and 5.8 eV or less.

[0046] <Base Coating>

[0047] In the undercoat layer of the electrophotographic photosensitive member of the present disclosure, when the ionization potential of the undercoat layer is represented by I Pu, I Pu is 6.0 eV or more,

[0048] When the ionization potential of the support is represented by IPs, IPs is lower than I Pu,

[0049] The primer layer comprises a compound (α),

[0050] When the ionization potential of the compound (α) is represented by IPα, IPα is 5.0 eV or more and 5.4 eV or less, and

[0051] IPs and IPα satisfy the following relation expression (1):

[0052] IPs ≥ IPα - 1.0 (1).

[0053] In the present disclosure, the ionization potential I Pu of the undercoat layer is preferably 6.0 eV or more and 6.3 eV or less.

[0054] In the present disclosure, from the viewpoint of efficiently injecting holes from the support into the undercoat layer, IPs and IPα preferably satisfy the following relational expression (2).

[0055] IPs ≥ IPα (2).

[0056] For the same reason, in the present disclosure, IPs and IPα more preferably satisfy the following relational expression (3).

[0057] IPs - IPα ≥ 0.3 (3).

[0058] In the compound (α) included in the undercoat layer according to the present disclosure, IPa is 5.0 eV or more and 5.4 eV or less.

[0059] The compound (α) contained in the undercoat layer according to the present disclosure is preferably a compound represented by the following formula (α).

[0060]

[0061] (In formula (α), Ar 1 and Ar 2 Each independently represents a substituted or unsubstituted phenyl group; the substituent is an alkyl group or an alkoxy group; and Ar 3 represents an n-valent aromatic group, wherein n is an integer of 1 to 3. )

[0062] The compound (α) represented by the formula (α) may be used alone or in combination of two or more thereof.

[0063] (Compound (α) represented by formula (α))

[0064] The compound (α) represented by the formula (α) is a hole transporting substance. Specific examples of the compound (α) represented by the formula (α) and the ionization potential IPα of the compound (α) are shown in Table 1 below.

[0065] Table 1

[0066]

[0067]

[0068] The ionization potential in the present disclosure was measured under a nitrogen atmosphere using a photoelectron spectrophotometer AC-3 manufactured by Riken Keiki Co., Ltd.

[0069] The undercoat layer in the present disclosure preferably includes a cured product of a composition including a compound represented by the following formula (B1) or (B2):

[0070]

[0071] Where R 101 To R 106 and R 201 To R 210 Each independently represents a monovalent group represented by the following formula (C), a hydrogen atom, a cyano group, a nitro group, a halogen atom, an alkoxycarbonyl group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group and a substituted or unsubstituted heterocyclic group, provided that R 101 To R 106 At least one of R 201 To R 210 At least one of the alkyl groups is a monovalent group represented by the following formula (C); one CH 2 is optionally substituted with O or S, or one CH in the alkyl group is optionally substituted with N; the substituent of the substituted alkyl group is at least one group selected from the group consisting of an aryl group, an alkoxycarbonyl group, a halogen atom and a hydroxyl group; and the substituent of the substituted aryl group and the substituted heterocyclic group is at least one group selected from the group consisting of a halogen atom, a nitro group, a cyano group, an alkyl group, an alkyl group substituted with a halogen group, and an alkoxy group,

[0072] wherein at least one of a, b and c has at least one group selected from the group consisting of a hydroxyl group, a thiol group, an amino group and a carboxyl group; and l and m are each independently 0 or 1, and the sum of l and m is greater than or equal to 0 and less than or equal to 2;

[0073] a represents an alkylene group having 1 to 6 carbon atoms in the main chain, an alkylene group having 1 to 6 carbon atoms in the main chain substituted by an alkyl group having 1 to 6 carbon atoms, an alkylene group having 1 to 6 carbon atoms in the main chain substituted by a benzyl group, an alkylene group having 1 to 6 carbon atoms in the main chain substituted by an alkoxycarbonyl group, or an alkylene group having 1 to 6 carbon atoms in the main chain substituted by a phenyl group, wherein these alkylene groups optionally have at least one group selected from the group consisting of a hydroxyl group, a mercapto group, an amino group, and a carboxyl group as a substituent; one CH in the main chain of each of these alkylene groups is 2are optionally substituted by O or S; or one CH in the main chain of each of these alkylene groups is optionally substituted by N;

[0074] b represents a phenylene group, a phenylene group substituted by an alkyl group having 1 to 6 carbon atoms, a phenylene group substituted by a nitro group, a phenylene group substituted by a halogen group, or a phenylene group substituted by an alkoxy group, wherein these phenylene groups optionally have at least one group selected from the group consisting of a hydroxyl group, a mercapto group, an amino group, and a carboxyl group as a substituent; and

[0075] c represents a hydrogen atom, a carboxyl group, an alkyl group having 1 or more and 6 or less carbon atoms in the main chain, or an alkyl group having 1 or more and 6 or less carbon atoms in the main chain substituted by an alkyl group having 1 or more and 5 or less carbon atoms, wherein these alkyl groups optionally have at least one group selected from the group consisting of a hydroxyl group, a mercapto group, an amino group and a carboxyl group as a substituent.

[0076] In addition, a compound selected from the group consisting of a compound represented by formula (B1) and a compound represented by formula (B2) may be used alone or in combination of two or more thereof.

[0077] (Compound represented by formula (B1) and compound represented by formula (B2))

[0078] The compound represented by the formula (B1) and the compound represented by the formula (B2) are electron transport substances. The compound represented by the formula (B1) and the compound represented by the formula (B2) are shown in the following Tables 2-1 to 2-7.

[0079] Compounds (B101) to (B168) are specific examples of compounds represented by formula (B1), and compounds (B201) to (B231) are specific examples of compounds represented by formula (B2). In Tables 2-1 to 2-7, when c is recorded as "(H)", this means that c represents a hydrogen atom in the structure shown in column a or b, and the structure of formula (C) is the structure shown in column a or b. When column a or b is (-), this means that l or m is 0.

[0080] The following are specific examples, and the effects of the present disclosure are not brought about only by the following specific examples. These compounds may be used alone, or a plurality of compounds may be mixed together and used.

[0081] Table 2-1

[0082]

[0083] Table 2-2

[0084]

[0085] Table 2-3

[0086]

[0087] Table 2-4

[0088]

[0089] Table 2-5

[0090]

[0091] Table 2-6

[0092]

[0093] Table 2-7

[0094]

[0095] The structures of the monovalent groups represented by formula (C) listed in the above table can be described as follows.

[0096] Specifically, the monovalent group represented by formula (C) is an alkyl group having 1 or more and 12 or less carbon atoms, a phenyl group, or a phenylalkyl group having 6 or more and 12 or less carbon atoms, each optionally having a substituent.

[0097] wherein the substituent optionally possessed by the alkyl group having 1 or more and 12 or less carbon atoms is any one of a hydroxyl group, a mercapto group, an amino group, a carboxyl group, an alkoxycarbonyl group and an alkoxy group;

[0098] The substituent optionally possessed by the phenyl group or the phenylalkyl group having 6 or more and 12 or less carbon atoms is methyl, ethyl, hydroxymethyl, hydroxyethyl, carboxymethyl, carboxyethyl, hydroxyl, mercapto, amino, carboxyl or alkoxycarbonyl; and

[0099] One CH of an alkyl group having 1 to 12 carbon atoms or a phenylalkyl group having 6 to 12 carbon atoms 2 is optionally substituted by O or S, or one CH of the alkyl group is optionally substituted by N,

[0100] The monovalent group represented by the formula (C) includes any one of a hydroxyl group, a mercapto group, an amino group and a carboxyl group.

[0101] In order to more effectively obtain the effect of the present disclosure, the value of the mass ratio of the content of the compound (α) in the above composition to the content of the compound represented by formula (B1) or (B2) in the above composition is preferably 0.035 or more and 0.150 or less. In other words, the content of the compound (α) is preferably 3.5% by mass or more and 15% by mass or less relative to the compound represented by formula (B1) or (B2).

[0102] The primer layer may contain polyester resin, polycarbonate resin, polyvinyl acetal resin, acrylic resin, epoxy resin, melamine resin, polyurethane resin, phenolic resin, polyvinyl phenolic resin, alkyd resin, polyvinyl alcohol resin, polyethylene oxide resin, polypropylene oxide resin, polyamide resin, polyamic acid resin, polyimide resin, polyamide-imide resin and cellulose resin as resins.

[0103] For the purpose of improving electrical characteristics, the undercoat layer may contain metal oxide particles, metal particles, conductive polymers, and the like.

[0104] Examples of metal oxides include indium tin oxide, tin oxide, indium oxide, titanium oxide, zinc oxide, aluminum oxide, and silicon dioxide. Examples of metals include gold, silver, and aluminum.

[0105] In addition, the undercoat layer may further contain additives.

[0106] In order to more effectively obtain the effects of the present disclosure, the film thickness of the undercoat layer is preferably 0.5 μm or more and 2.4 μm or less.

[0107] The undercoat layer can be formed by preparing an undercoat layer coating solution comprising the above-mentioned materials and a solvent, forming a coating film of the undercoat layer coating solution, and drying and / or curing the coating film. Examples of the solvent used in the undercoat layer coating solution include alcohol solvents, ketone solvents, ether solvents, ester solvents, and aromatic hydrocarbon solvents.

[0108] <Photosensitive layer>

[0109] The photosensitive layer of the electrophotographic photosensitive member is mainly classified into (1) a laminated photosensitive layer and (2) a single-layer photosensitive layer. (1) The laminated photosensitive layer includes a charge generating layer containing a charge generating substance and a charge transporting layer (hole transporting layer) containing a charge transporting substance. (2) The single-layer photosensitive layer is a photosensitive layer containing both a charge generating substance and a charge transporting substance.

[0110] (1) Laminated photosensitive layer

[0111] The laminated photosensitive layer includes a charge generating layer and a charge transporting layer.

[0112] (1-1) Charge Generation Layer

[0113] The charge generating layer preferably contains a charge generating substance and a resin (binder resin).

[0114] Examples of the charge generating material include azo pigments, perylene pigments, polycyclic quinone pigments, indigo pigments and phthalocyanine pigments. Among these pigments, azo pigments and phthalocyanine pigments are preferred. Among phthalocyanine pigments, oxytitanium phthalocyanine pigments, chlorogallium phthalocyanine pigments and hydroxygallium phthalocyanine pigments are preferred.

[0115] 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.

[0116] Examples of the resin include polyester resins, polycarbonate resins, polyvinyl acetal resins, polyvinyl butyral resins, acrylic resins, silicone resins, epoxy resins, melamine resins, polyurethane resins, phenolic resins, polyvinyl alcohol resins, cellulose resins, polystyrene resins, polyvinyl acetate resins, and polyvinyl chloride resins. Among these resins, polyvinyl butyral resins are preferred.

[0117] In addition, the charge generation layer may contain additives such as an antioxidant and an ultraviolet absorber. Specific examples thereof include hindered phenol compounds, hindered amine compounds, sulfur compounds, phosphorus compounds, and benzophenone compounds.

[0118] The film thickness of the charge generating layer is preferably 0.1 μm or more and 1 μm or less, and more preferably 0.15 μm or more and 0.4 μm or less.

[0119] The charge generation layer can be formed by preparing a charge generation layer coating liquid containing the above-mentioned materials and a solvent, forming a coating film of the charge generation layer coating liquid, and drying the coating film. Examples of the solvent to be used for the charge generation layer coating liquid include alcohol solvents, sulfoxide solvents, ketone solvents, ether solvents, ester solvents, and aromatic hydrocarbon solvents.

[0120] (1-2) Charge transport layer

[0121] The charge transporting layer preferably contains a charge transporting substance and a resin (binder resin).

[0122] Examples of the charge transporting substance include polycyclic aromatic compounds, heterocyclic compounds, hydrazone compounds, styryl compounds, enamine compounds, benzidine compounds, triarylamine compounds, and resins having groups derived from these substances. Among these compounds, triarylamine compounds and benzidine compounds are preferred.

[0123] The content of the charge transporting substance in the charge transporting layer is preferably 25% by mass or more and 70% by mass or less, and more preferably 30% by mass or more and 55% by mass or less, relative to the total mass of the charge transporting layer.

[0124] Examples of resins include polyester resins, polycarbonate resins, acrylic resins, and polystyrene resins. Among these resins, polycarbonate resins and polyester resins are preferred. Among polyester resins, polyarylate resins are particularly preferred.

[0125] The content ratio of the charge transporting substance to the resin in the charge transporting layer (mass ratio, charge transporting substance:resin) is preferably from 4:10 to 20:10, more preferably from 5:10 to 12:10.

[0126] The charge transport layer may contain additives such as antioxidants, ultraviolet absorbers, plasticizers, leveling agents, slip agents and wear resistance improvers. Specific additives include hindered phenol compounds, hindered amine compounds, sulfur compounds, phosphorus compounds, benzophenone compounds, siloxane modified resins, silicone oils, fluorocarbon resin particles, polystyrene resin particles, polyethylene resin particles, silica particles, aluminum oxide particles and boron nitride particles.

[0127] The film thickness of the charge transport layer is preferably 5 μm or more and 50 μm or less, more preferably 8 μm or more and 40 μm or less, particularly preferably 10 μm or more and 30 μm or less.

[0128] The charge transport layer can be formed by preparing a charge transport layer coating solution containing the above-mentioned materials and a solvent, forming a coating film of the charge transport layer coating solution, and drying the coating film. Examples of solvents to be used for the charge transport layer coating solution include alcohol solvents, ketone solvents, ether solvents, ester solvents, and aromatic hydrocarbon solvents. Among these solvents, ether solvents and aromatic hydrocarbon solvents are preferred.

[0129] <Protective layer>

[0130] In the present disclosure, a protective layer may be provided on the photosensitive layer. By providing the protective layer therein, the electrophotographic photosensitive member can improve its durability.

[0131] The protective layer preferably contains conductive particles and / or a charge transporting substance, and a resin.

[0132] Examples of the conductive particles include metal oxide particles and metal particles. Examples of the metal oxide include titanium oxide, zinc oxide, tin oxide, and indium oxide.

[0133] Examples of the charge transporting substance include polycyclic aromatic compounds, heterocyclic compounds, hydrazone compounds, styryl compounds, enamine compounds, benzidine compounds, triarylamine compounds, and resins having groups derived from these substances. Among these substances, triarylamine compounds and benzidine compounds are preferred.

[0134] Examples of the resin include polyester resins, acrylic resins, phenoxy resins, polycarbonate resins, polystyrene resins, phenolic resins, melamine resins, and epoxy resins. Among these resins, polycarbonate resins, polyester resins, and acrylic resins are preferred.

[0135] The protective layer can also be formed into a cured film by polymerization of a composition containing a monomer having a polymerizable functional group. Examples of the polymerization reaction at this time include thermal polymerization, photopolymerization, and radiation-induced polymerization. Examples of the polymerizable functional group possessed by the monomer having a polymerizable functional group include acryloyl and methacryloyl. A compound having a charge transporting ability can be used as the monomer having a polymerizable functional group.

[0136] The protective layer may contain additives such as antioxidants, ultraviolet absorbers, plasticizers, leveling agents, slip agents and wear resistance improvers. Specific additives include hindered phenol compounds, hindered amine compounds, sulfur compounds, phosphorus compounds, benzophenone compounds, siloxane modified resins, silicone oils, fluorocarbon resin particles, polystyrene resin particles, polyethylene resin particles, silicon dioxide particles, aluminum oxide particles and boron nitride particles.

[0137] The film thickness of the protective layer is preferably 0.5 μm or more and 10 μm or less, and more preferably 1 μm or more and 7 μm or less.

[0138] The protective layer can be formed by preparing a protective layer coating liquid containing the above-mentioned materials and a solvent, forming a coating film of the protective layer coating liquid, and drying and / or curing the coating film. Examples of the solvent to be used for the protective layer coating liquid include alcohol solvents, ketone solvents, ether solvents, sulfoxide solvents, ester solvents, and aromatic hydrocarbon solvents.

[0139] [Process cartridge and electrophotographic apparatus]

[0140] The process cartridge of the present disclosure integrally supports: the above-mentioned electrophotographic photosensitive member; and at least one unit selected from the group consisting of a charging unit, a developing unit, and a cleaning unit, and is detachably mountable to a main body of an electrophotographic apparatus.

[0141] An electrophotographic apparatus of the present disclosure includes: the above-mentioned electrophotographic photosensitive member; and a charging unit, an exposure unit, a developing unit, and a transfer unit.

[0142] Figure 1 One example of a schematic configuration of an electrophotographic apparatus including a process cartridge provided with an electrophotographic photosensitive member is shown.

[0143] A cylindrical electrophotographic photosensitive member 1 is rotationally driven in the direction of an arrow at a predetermined peripheral speed about an axis 2. The surface of the electrophotographic photosensitive member 1 is electrostatically charged by a charging unit 3 to a predetermined positive or negative potential.

[0144] exist Figure 1 In FIG. 1 , a roller charging system using a roller-type charging member (charging roller) is shown, but a charging system such as a corona charging system, a proximity charging system, or an injection charging system may also be adopted.

[0145] The surface of the electrophotographic photosensitive member 1 charged with static electricity is irradiated with exposure light 4 emitted from an exposure unit (not shown), and an electrostatic latent image corresponding to target image information is formed on the surface. The electrostatic latent image formed on the surface of the electrophotographic photosensitive member 1 is developed by a toner contained in a developing unit 5, and a toner image is formed on the surface of the electrophotographic photosensitive member 1. The toner image formed on the surface of the electrophotographic photosensitive member 1 is transferred onto a transfer material 7 by a transfer unit 6. The transfer material 7 to which the toner image has been transferred is conveyed to a fixing unit 8, subjected to a fixing process of the toner image, and printed to the outside of the electrophotographic apparatus.

[0146] The electrophotographic apparatus may include a cleaning unit 9 for removing attached substances such as toner remaining on the surface of the transferred electrophotographic photosensitive member 1. Alternatively, the cleaning unit 9 may not be provided separately, but a so-called cleaner-less system may be used, which removes the above-mentioned attached substances by the developing unit 5 or the like.

[0147] The electrophotographic apparatus may have a destaticizing mechanism that performs a destaticizing treatment on the surface of the electrophotographic photosensitive member 1 by pre-exposure light emitted from a pre-exposure unit (not shown). In addition, a guide unit 12 such as a rail may be provided so that the process cartridge 11 of the present disclosure can be detachably mounted to the main body of the electrophotographic apparatus.

[0148] The electrophotographic photosensitive member of the present disclosure can be used for a laser beam printer, an LED printer, a copying machine, a facsimile machine, a multifunctional machine thereof, and the like.

[0149] [Example]

[0150] The present disclosure will be described in more detail below with reference to Examples and Comparative Examples. The present disclosure is not limited to the following Examples at all, as long as the present disclosure does not exceed its purport. Here, unless otherwise stated, the "parts" in the description of the following Examples are based on mass.

[0151] [Production Examples of Compounds Represented by Formula (B1) and Compounds Represented by Formula (B2)]

[0152] The compound represented by formula (B1) (derivative of electron transport material) can be synthesized using, for example, U.S. Patent No. 4442193, U.S. Patent No. 4992349, U.S. Patent No. 5468583 and Chemistry of materials, Vol. 19, No. 11, 2703-2705 (2007) known synthesis methods. Alternatively, the compound can be synthesized by reaction between naphthalenetetracarboxylic dianhydride and monoamine derivatives commercially available from Tokyo Chemical Industry Co., Ltd., Sigma-Aldrich Japan KK and Johnson Matthey Japan GK.

[0153] The compound represented by formula (B1) includes a polymerizable functional group (hydroxyl, mercapto, amino and carboxyl) that can be polymerized with the isocyanate group of the isocyanate compound. As a method for introducing these substituents into the compound represented by formula (B1), there is a method for directly introducing the polymerizable functional group into the compound represented by formula (B1), and a method for introducing a structure having the above-mentioned polymerizable functional group or a functional group that can serve as a precursor of the polymerizable functional group. An example of the latter method includes a method for introducing an aryl group containing a functional group using a halide based on a naphthalene imide derivative and a cross-coupling reaction using a palladium catalyst and a base. An example of the method also includes using a halide based on a naphthalene imide derivative and using FeCl 3 A method for introducing an alkyl group containing a functional group by cross-coupling reaction of a catalyst and a base. In addition, examples of the method also include a method of lithiation of a halide of a naphthalene imide derivative and then reacting an epoxy compound or CO 2 A method of introducing a hydroxyalkyl group or a carboxyl group by acting on the lithiated product. There is a method of using a naphthalenetetracarboxylic dianhydride derivative or a monoamine derivative each having the above-mentioned polymerizable functional group or a functional group that can serve as a precursor of a polymerizable functional group as a raw material for synthesizing a naphthaleneimide derivative.

[0154] The compound represented by formula (B2) (derivative of electron transport material) can be synthesized using a known synthesis method described in, for example, Journal of the American Chemical Society, Vol. 129, No. 49, 15259 to 15278 (2007). Alternatively, the compound can be synthesized by reacting perylene tetracarboxylic dianhydride and a monoamine derivative commercially available from Tokyo Chemical Industry Co., Ltd., Sigma-Aldrich Japan KK and Johnson Matthey Japan GK as a reagent.

[0155] The compound represented by formula (B2) has a functional group (hydroxyl, thiol, amino and carboxyl) that can be polymerized with the isocyanate group of the isocyanate compound. As a method for introducing these polymerizable functional groups into the compound represented by formula (B2), in addition to the method of directly introducing the polymerizable functional group into the compound represented by formula (B2), there is also a method of introducing a structure having the above-mentioned polymerizable functional group or a functional group that can serve as a polymerizable functional group precursor. Examples of the latter method include a method using a halide based on a perylene imide derivative and a cross-coupling reaction using a palladium catalyst and a base. In addition, for example, there is a method using a halide based on a perylene imide derivative and using FeCl 3 A method of cross-coupling reaction using a catalyst and a base. In addition, there is a method of using a perylene tetracarboxylic dianhydride derivative or a monoamine derivative each having a polymerizable functional group or a functional group that can serve as a precursor of a polymerizable functional group as a raw material when synthesizing a perylene imide derivative.

[0156] (Synthesis example 1)

[0157] Under a nitrogen atmosphere, 5.4 parts of naphthalenetetracarboxylic dianhydride, 4 parts of 2-methyl-6-ethylaniline and 3 parts of 2-amino-1-butanol were added to 200 parts of dimethylacetamide, and the mixture was stirred at room temperature for 1 hour to prepare a solution. After the solution was prepared, the solution was refluxed for 8 hours; the precipitate was separated by filtration and recrystallized in ethyl acetate; 1.0 part of compound B101 was obtained.

[0158] (Synthesis example 2)

[0159] Under a nitrogen atmosphere, 5.4 parts of naphthalenetetracarboxylic dianhydride, 4 parts of 4-heptylamine and 3 parts of 2-amino-1,3-propanediol were added to 200 parts of dimethylacetamide, and the mixture was stirred at room temperature for 1 hour to prepare a solution. After the solution was prepared, the solution was refluxed for 8 hours, the target substance was separated by silica gel column chromatography (developing solvent: ethyl acetate / toluene), and then the fraction containing the target substance was concentrated. The concentrated product was recrystallized in a mixed solution of ethyl acetate / toluene to obtain 2.0 parts of compound B154.

[0160] (Synthesis example 3)

[0161] Under a nitrogen atmosphere, 7.4 parts of perylene tetracarboxylic dianhydride (produced by Tokyo Chemical Industry Co., Ltd.), 4 parts of 2,6-diethylaniline (produced by Tokyo Chemical Industry Co., Ltd.) and 4 parts of 2-aminophenylethanol were added to 200 parts of dimethylacetamide, and the mixture was stirred at room temperature for 1 hour to prepare a solution. After the solution was prepared, the solution was refluxed for 8 hours; the precipitate was separated by filtration and recrystallized in ethyl acetate; 5.0 parts of compound B203 were obtained.

[0162] <Manufacturing of Support Body>

[0163] (Manufacturing Example of Support Body 1)

[0164] A support 1 is obtained by obtaining an aluminum cylinder (JIS-A3003, aluminum alloy) having a length of 370 mm and a diameter of 30.5 mm, and roughening its surface by processing it with a drill bit (bite) of R 40 mm at a pitch of 0.4 mm, and then by ultrasonically cleaning the aluminum cylinder in an alkaline liquid having a pH value of 11, removing the alkaline liquid with pure water, leaving the aluminum cylinder to stand in hot water at 95° C. for 90 seconds, and then drying the aluminum cylinder at room temperature.

[0165] (Manufacturing Example of Support Body 2)

[0166] A support 2 is obtained by obtaining an aluminum cylinder (JIS-A3003, aluminum alloy) having a length of 370 mm and a diameter of 30.5 mm, and roughening its surface by processing it with a pitch of 0.4 mm using a drill bit of R 40 mm, and then ultrasonically cleaning the aluminum cylinder in an alkaline liquid having a pH value of 11, removing the alkaline liquid with pure water, leaving the aluminum cylinder to stand in hot water at 95° C. for 60 seconds, and then drying the aluminum cylinder at room temperature.

[0167] (Manufacturing Example of Support Body 3)

[0168] A support 3 is obtained by obtaining an aluminum cylinder (JIS-A3003, aluminum alloy) having a length of 370 mm and a diameter of 30.5 mm, and roughening its surface by processing it with a drill bit of R 40 mm at a pitch of 0.4 mm, then ultrasonically cleaning the aluminum cylinder in an alkaline liquid having a pH value of 11, removing the alkaline liquid with pure water, leaving the aluminum cylinder to stand in hot water at 95°C for 100 seconds, and then drying the aluminum cylinder at room temperature.

[0169] (Manufacturing Example of Support Body 4)

[0170] A support body 4 is obtained by obtaining an aluminum cylinder (JIS-A3003, aluminum alloy) having a length of 370 mm and a diameter of 30.5 mm, and roughening its surface by processing it with a drill bit of R 40 mm at a pitch of 0.4 mm, then ultrasonically cleaning the aluminum cylinder in an alkaline liquid having a pH value of 11, removing the alkaline liquid with pure water, leaving the aluminum cylinder to stand in warm water at 60°C for 15 seconds, and then drying the aluminum cylinder at room temperature.

[0171] <Manufacture of Electrophotographic Photosensitive Member>

[0172] (Production Example of Photosensitive Member 1)

[0173] The support body 1 serves as a support body.

[0174] Next, 3.11 parts of the compound (B154) as an electron transporting substance, 0.40 parts of styrene-acrylic resin (trade name: UC-3920, produced by Toagosei Co., Ltd.) and 0.4 parts of polyvinyl butyral resin (trade name: BX-1, produced by Sekisui Chemical Co., Ltd.) as a resin, and 6.49 parts of a blocked isocyanate compound (trade name: SBB-70P, produced by Asahi Kasei Corp.) as an isocyanate compound were dissolved in a mixed solvent of 48 parts of 1-butanol and 24 parts of acetone. To this solution, 0.25 parts of a liquid in which the compound (α1) (produced by Tokyo Chemical Industry Co., Ltd.) was dissolved in 6 parts of tetrahydrofuran was added, and the mixture was stirred for 1 hour. After that, the mixture was subjected to filter pressing using a Teflon (trademark) filter (product name: PF020) manufactured by ADVANTEC. The obtained coating liquid for an undercoat layer was applied onto the above support by dip coating, and the obtained coating film was heated at 170° C. for 40 minutes to be cured (polymerized), thereby forming an undercoat layer having a film thickness of 1.8 μm on the support.

[0175] Next, 20 parts of hydroxygallium phthalocyanine (charge generating material) in the form of a crystal having peaks at Bragg angles 2θ±0.2° of 7.4° and 28.2° in CuKα characteristic X-ray diffraction, 0.2 parts of a calixarene compound represented by the following formula (P),

[0176]

[0177] 10 parts of polyvinyl butyral (trade name: S-LEC BX-1, produced by Sekisui Chemical Co., Ltd.) and 600 parts of cyclohexane were charged into a sand mill using glass beads having a diameter of 1 mm, and the mixture was subjected to a dispersion treatment for 4 hours. Thereafter, 700 parts of ethyl acetate were added to the mixture to prepare a coating liquid for a charge generation layer. The coating liquid for a charge generation layer was applied to the above-mentioned undercoat layer by dip coating, and the obtained coating film was dried at 80° C. for 15 minutes to form a charge generation layer having a film thickness of 0.17 μm.

[0178] Next, 30 parts of a compound (charge transporting substance) represented by the following formula (Q), 60 parts of a compound (charge transporting substance) represented by the following formula (R), and 10 parts of a compound (charge transporting substance) represented by the following formula (S), and

[0179] 100 parts of a polycarbonate resin (trade name: Iupilon Z400, produced by Mitsubishi Engineering-Plastics Corporation, bisphenol Z type polycarbonate) and 0.02 parts of a polycarbonate resin represented by the following formula (T) (viscosity average molecular weight Mv: 20000)

[0180]

[0181] (where 0.95 and 0.05 are the molar ratios (copolymerization ratios) between the two units)

[0182] Dissolved in a mixed solvent of 600 parts of mixed xylene and 200 parts of dimethoxymethane to prepare a charge transport layer coating liquid. The charge transport layer coating liquid was applied to the above charge generating layer by dip coating to form a coating film, and the obtained coating film was dried at 100° C. for 30 minutes to form a charge transport layer having a film thickness of 18 μm.

[0183] Next, a mixed solvent of 20 parts of 1,1,2,2,3,3,4-heptafluorocyclopentane (trade name: ZEORORAH, manufactured by Zeon Corporation) and 20 parts of 1-propanol was prepared and filtered through a polyflon filter (trade name: PF-040, manufactured by Advantec Toyo Kaisha, Ltd.).

[0184] 90 parts of a hole transport compound represented by the following formula (U)

[0185]

[0186] 70 parts of 1,1,2,2,3,3,4-heptafluorocyclopentane and 70 parts of 1-propanol are added to the above-mentioned mixed solvent. The resultant is filtered through a polytetrafluoroethylene resin filter (trade name: PF-020, manufactured by Advantec Toyo Kaisha, Ltd.) to prepare a coating solution for a second charge transport layer (protective layer). The coating solution for the second charge transport layer is applied to the above-mentioned charge transport layer by dip coating, and the obtained coating film is dried in air at 50°C for 6 minutes. Afterwards, in a nitrogen atmosphere, under the conditions of an accelerating voltage of 70kV and an absorbed dose of 8000Gy, the coating film is irradiated with an electron beam for 1.6 seconds while the support (irradiated body) is rotated at 200rpm. Subsequently, the temperature is raised from 25°C to 125°C in nitrogen for 30 seconds, and the coating film is heated. When the coating film is irradiated with an electron beam and then heated, the oxygen concentration in the atmosphere is 15ppm. Next, the resultant was subjected to heat treatment in air at 100° C. for 30 minutes, thereby forming a second charge transport layer (protective layer) that was cured by electron beams and had a film thickness of 5 μm.

[0187] Next, a grinding sheet (trade name: GC3000, manufactured by Riken Corundum Co., Ltd.) was used to form linear grooves on the surface of the protective layer. The feed speed of the grinding sheet was set to 40 mm / min, the number of revolutions of the workpiece was set to 240 rpm, and the pressing pressure of the grinding sheet on the workpiece was set to 7.5 N / m 2 The feeding direction of the grinding sheet and the rotation direction of the workpiece were set to be the same. In addition, a backup roller with an outer diameter of 40 cm and an Asker C hardness of 40 was used. Under these conditions, linear grooves were formed on the circumferential surface of the workpiece over 10 seconds.

[0188] Thus, the photosensitive member 1 was produced.

[0189] (Production Examples of Electrophotographic Photosensitive Members 2 to 76)

[0190] Electrophotographic photosensitive members were produced in the same manner as in the production example of photosensitive member 1, except that the supports, compounds represented by formula (α), addition amounts, and film thicknesses of undercoats shown in Tables 3-1-1 to 3-2-2 were changed as shown in Tables 3-1-1 to 3-2-2. The obtained electrophotographic photosensitive members shall be designated as photosensitive members 2 to 76.

[0191] Table 3-1-1

[0192]

[0193]

[0194] Table 3-1-2

[0195]

[0196]

[0197] Table 3-2-1

[0198]

[0199]

[0200] Table 3-2-2

[0201]

[0202]

[0203] (Manufacturing Example of Electrophotographic Photosensitive Member 101)

[0204] A cylindrical aluminum substrate having a length of 370 mm and a diameter of 30.5 mm was used as a support.

[0205] An electrophotographic photosensitive member was produced in the same manner as in Production Example of Photosensitive Member 1, except that compound (α1) was not added to the support and the undercoat layer coating solution as shown in Tables 4-1-1 and 4-1-2.

[0206] (Manufacturing Example of Photosensitive Member 102)

[0207] An aluminum cylinder (JIS-A3003, aluminum alloy) with a length of 370 mm and a diameter of 30.5 mm was used as a support (conductive support). Next, 19.5 parts of blocked isocyanate (Sumidur BL3175, produced by Sumika Covestro Urethane Co., Ltd., solid fraction 75% by mass) and 7.5 parts of butyraldehyde resin (S-LEC BL-1, produced by Sekisui Chemical Co., Ltd.) were dissolved in 130 parts of methyl ethyl ketone. Next, 34 parts of Pigment Orange 43 (produced by Tokyo Chemical Industry Co., Ltd.) and 0.9 parts of Comparative Example Compound 1 were mixed with the above-mentioned solution, and then the mixture was dispersed in a sand mill for 10 hours to obtain a dispersion. 0.005 parts of bismuth carboxylate (K-KATXK-640, produced by King Industries Inc.) were added to the dispersion to obtain a coating solution for the undercoat layer. The coating liquid for the undercoat layer was applied to the support by dip coating, and the obtained coating film was cured at 160° C. for 60 minutes to obtain an undercoat layer having a thickness of 7 μm. All layers above the undercoat layer were formed in the same manner as in the manufacturing example of the photosensitive member 1, and an electrophotographic photosensitive member was manufactured. The obtained electrophotographic photosensitive member shall be designated as photosensitive member 102.

[0208] (Manufacturing Example of Photosensitive Members 103 to 104)

[0209] Except that the formation conditions of the undercoat layer were changed as described in Tables 4-1-1 and 4-1-2, an electrophotographic photosensitive member was produced in the same manner as the photosensitive member 102. The obtained photosensitive members shall be designated as photosensitive members 103 to 104.

[0210] (Production Example of Photosensitive Member 105)

[0211] An electrophotographic photosensitive member was produced in the same manner as Photosensitive Member 1 except that the support described in Table 4-1-1 was used and the formation conditions of the undercoat layer were changed as described in Tables 4-1-1 and 4-1-2. The obtained photosensitive member shall be designated as Photosensitive Member 105 .

[0212] (Manufacturing Example of Photosensitive Member 106)

[0213] First, 46.7 parts of blocked isocyanate (Sumidur BL3175, produced by SumikaCovestro Urethane Co., Ltd., solid fraction 75% by mass) as a curing agent and 5 parts of a triarylamine compound having a reactive group (Comparative Example Compound 10) were dissolved in 100 parts of methyl ethyl ketone and 100 parts by mass of cyclopentanone. 60 parts of Pigment Orange 43 (produced by Tokyo Chemical Industry Co., Ltd.) were mixed into the solution, and the mixture was dispersed in a sand mill using glass beads for 4 hours; 0.001 parts of bismuth carboxylate (produced by King Industries Inc.) were added to the obtained dispersion as a catalyst to obtain a coating liquid for an undercoat layer. The coating liquid was applied to the cylindrical aluminum support shown in Table 4-1-1 by dip coating, and the coating film was dried and cured at 160°C for 45 minutes to form an undercoat layer having a film thickness of 4.2 μm. An electrophotographic photosensitive member was produced by forming all layers above the undercoat layer in the same manner as in the production example of the photosensitive member 1. The obtained electrophotographic photosensitive member shall be designated as a photosensitive member 106.

[0214] (Production Example of Photosensitive Member 107)

[0215] First, 40 parts of blocked isocyanate (Sumidur BL3175, produced by Sumika Covestro Urethane Co., Ltd., solid fraction 75% by mass) as a curing agent, 5 parts of a triarylamine compound having a reactive group (Comparative Example Compound 15) and 5 parts of a butyraldehyde resin (S-LEC BL-1, produced by Sekisui Chemical Co., Ltd.) were dissolved in 100 parts of methyl ethyl ketone and 100 parts by mass of cyclopentanone. 60 parts of Pigment Orange 43 (produced by Tokyo Chemical Industry Co., Ltd.) were mixed into the solution, and the mixture was dispersed in a sand mill using glass beads for 4 hours; 0.001 parts of bismuth carboxylate (produced by King Industries Inc.) was added to the obtained dispersion as a catalyst to obtain a coating solution for an undercoat layer. The coating liquid was applied to the cylindrical aluminum support shown in Table 4-1-1 by dip coating, and the coating film was dried and cured at 160° C. for 45 minutes to form an undercoat layer having a film thickness of 4.2 μm.

[0216] An electrophotographic photosensitive member was produced by forming all layers above the undercoat layer in the same manner as in the production example of the photosensitive member 1. The obtained electrophotographic photosensitive member shall be designated as a photosensitive member 107.

[0217] (Production Example of Photosensitive Member 108)

[0218] First, 40 parts of blocked isocyanate (Sumidur BL3175, produced by Sumika Covestro Urethane Co., Ltd., solid fraction 75% by mass) as a curing agent, 5 parts of a triarylamine compound having a reactive group (Comparative Example Compound 15) and 5 parts of a butyraldehyde resin (S-LEC BL-1, produced by Sekisui Chemical Co., Ltd.) were dissolved in 100 parts of methyl ethyl ketone and 100 parts by mass of cyclopentanone. 60 parts of Pigment Orange 43 (produced by Tokyo Chemical Industry Co., Ltd.) were mixed into the solution, and the mixture was dispersed in a sand mill using glass beads for 4 hours; 0.001 parts of bismuth carboxylate (produced by King Industries Inc.) was added to the obtained dispersion as a catalyst to obtain a coating solution for an undercoat layer. The coating liquid was applied to the cylindrical aluminum support shown in Table 4-1-1 by dip coating, and the coating film was dried and cured at 160° C. for 45 minutes to form an undercoat layer having a film thickness of 1.8 μm.

[0219] An electrophotographic photosensitive member was produced by forming all layers above the undercoat layer in the same manner as in the production example of the photosensitive member 1. The obtained electrophotographic photosensitive member shall be designated as a photosensitive member 108.

[0220] Table 4-1-1

[0221]

[0222] Table 4-1-2

[0223]

[0224]

[0225] Table 5-1

[0226]

[0227]

[0228]

[0229] Table 5-2

[0230]

[0231]

[0232]

[0233] [evaluate]

[0234] (Examples 1 to 76 and Comparative Examples 1 to 8)

[0235] The photosensitive member 1 was prepared, mounted on a cyan station of an electrophotographic apparatus (copier) (trade name: image PRESSC 910, manufactured by Canon Inc.) as an evaluation apparatus, and evaluated in the following manner.

[0236] The surface potential of the electrophotographic photosensitive member was measured by taking out the developing cartridge from the evaluation apparatus, setting a potential probe (trade name: Model 6000B-8, manufactured by Midoriya Electric Co., Ltd.) therein, and using a surface potentiometer (Model 344: manufactured by Midoriya Electric Co., Ltd.).

[0237] The dark area potential (Vd) and the light area potential (Vl) were measured at 12 points at intervals of 30° in the circumferential direction at the axial center position of the electrophotographic photosensitive member, and the average values ​​for one rotation were calculated as the respective values.

[0238] First, the voltage applied to the charging roller was adjusted so that the dark area potential (Vd) of the first A4 paper in the electrophotographic photosensitive member for evaluation under an environment of 30°C / 80%RH became -680 V. Next, the image exposure light amount was adjusted so that the light area potential (Vl) of the first A4 paper became -380 V.

[0239] After 3 hours, under an environment of 30°C / 80% RH, 200 sheets of paper were passed through with the voltage applied to the charging roller set to make the dark area potential (Vd) become -680 V and the exposure light amount set to make the light area potential (Vl) become -380 V, and the light area potential during this period was measured.

[0240] The light potential of the first and 200th sheets was calculated by the above method, and the absolute value of (initial light potential - light potential after 200 sheets) was calculated and calculated as the short-term potential fluctuation value. The evaluation results are shown in Table 3-1-2, Table 3-2-2 and Table 4-1-2.

[0241] After measuring the light potential after passing 200 sheets of paper, the residual potential was measured by starting the measurement when the electrophotographic photosensitive member rotated one turn from the position where charging was cut off, and then measuring the potential of the electrophotographic photosensitive member rotating one turn. In addition, the residual potential was also measured at 12 points at intervals of 30° in the circumferential direction, as in the measurement of the light potential. Thereafter, the average value of the electrophotographic photosensitive member rotating one turn was calculated and determined as the residual potential.

[0242] The obtained evaluation results are shown in Table 3-1-2, Table 3-2-2 and Table 4-1-2.

[0243] AC-3 (manufactured by Riken Keiki Co., Ltd.) is used to measure the ionization potential of support, undercoat, compound (α) and comparative compound. The ionization potential of each single substance of compound (α) and comparative compound is measured. In addition, for support, the ionization potential is measured from the surface of the support obtained, and for undercoat, the ionization potential is measured from the surface of the undercoat after forming the undercoat. The starting energy is set to 4.00eV, the ending energy is set to 7.00eV, and the step size is set to 0.05eV. The evaluation results are shown in Table 3-1-1, Table 3-1-2, Table 3-2-1, Table 3-2-2, Table 4-1-1 and Table 4-1-2.

[0244] The residual potential and ionization potential of the undercoat layer were determined in the same manner except that the above-mentioned photosensitive member 1 was replaced with photosensitive members 2 to 76 and photosensitive members 101 to 108. The evaluation results obtained are shown in Tables 3-1-1, 3-1-2, 3-2-1, 3-2-2, 4-1-1 and 4-1-2.

[0245] According to the present disclosure, an electrophotographic photosensitive member having a low residual potential and small fluctuation in light-area potential can be provided.

[0246] While the present disclosure has been described with reference to exemplary embodiments, it is to be understood that the present disclosure is not limited to the disclosed exemplary embodiments.The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.

Claims

1. An electrophotographic photosensitive member comprising: A support, an undercoat layer directly formed on the support, and a photosensitive layer formed on the undercoat layer, wherein When the ionization potential of the undercoat layer is represented by I Pu, the I Pu is 6.0 eV or more, When the ionization potential of the support is represented by IPs, the IPs is lower than I Pu, The primer layer comprises compound α, When the ionization potential of the compound α is represented by IPα, the IPα is 5.0 eV or more and 5.4 eV or less, and The IPs and the IPα satisfy the following relational expression (1): IPs ≥ IPα - 1.0 (1).

2. The electrophotographic photosensitive member according to claim 1, wherein the IPs and the IPα satisfy the following relational expression (2): IPs ≥ IPα (2).

3. The electrophotographic photosensitive member according to claim 2, wherein the IPs and the IPα satisfy the following relational expression (3): IPs - IPα ≥ 0.3 (3).

4. The electrophotographic photosensitive member according to claim 1, wherein the compound α is a compound represented by the following formula (α): Among them, Ar 1 and Ar 2 Each independently represents a substituted or unsubstituted phenyl group; Ar 3 represents an n-valent aromatic group, wherein n is an integer of 1 to 3; and the substituent of the substituted phenyl group is an alkyl group or an alkoxy group.

5. The electrophotographic photosensitive member according to claim 1, wherein the undercoat layer comprises a cured product of a composition comprising a compound represented by the following formula (B1) or (B2): Where R 101 To R 106 and R 201 To R 210 Each independently represents a monovalent group represented by the following formula (C), a hydrogen atom, a cyano group, a nitro group, a halogen atom, an alkoxycarbonyl group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group and a substituted or unsubstituted heterocyclic group, provided that R 101 To R 106 At least one of R 201 To R 210 at least one of the substituted aryl groups and the substituted heterocyclic group is a monovalent group represented by the following formula (C); one CH2 in the alkyl group is optionally substituted by O or S, or one CH in the alkyl group is optionally substituted by N; the substituent of the substituted alkyl group is at least one group selected from the group consisting of an aryl group, an alkoxycarbonyl group, a halogen atom and a hydroxyl group; and the substituent of the substituted aryl group and the substituted heterocyclic group is at least one group selected from the group consisting of a halogen atom, a nitro group, a cyano group, an alkyl group, an alkyl group substituted by a halogen group, and an alkoxy group, wherein at least one of a, b and c has at least one group selected from the group consisting of a hydroxyl group, a thiol group, an amino group and a carboxyl group; and l and m are each independently 0 or 1, and the sum of l and m is greater than or equal to 0 and less than or equal to 2; a represents an alkylene group having 1 or more and 6 or less carbon atoms in the main chain, an alkylene group having 1 or more and 6 or less carbon atoms in the main chain substituted by an alkyl group having 1 or more and 6 or less carbon atoms, an alkylene group having 1 or more and 6 or less carbon atoms in the main chain substituted by a benzyl group, an alkylene group having 1 or more and 6 or less carbon atoms in the main chain substituted by an alkoxycarbonyl group, or an alkylene group having 1 or more and 6 or less carbon atoms in the main chain substituted by a phenyl group, wherein these alkylene groups optionally have at least one group selected from the group consisting of a hydroxyl group, a mercapto group, an amino group and a carboxyl group as a substituent; one CH2 in the main chain of each of these alkylene groups is optionally substituted by O or S; or one CH in the main chain of each of these alkylene groups is optionally substituted by N; b represents a phenylene group, a phenylene group substituted by an alkyl group having 1 to 6 carbon atoms, a phenylene group substituted by a nitro group, a phenylene group substituted by a halogen group, or a phenylene group substituted by an alkoxy group, wherein these phenylene groups optionally have at least one group selected from the group consisting of a hydroxyl group, a mercapto group, an amino group, and a carboxyl group as a substituent; and c represents a hydrogen atom, a carboxyl group, an alkyl group having 1 or more and 6 or less carbon atoms in the main chain, or an alkyl group having 1 or more and 6 or less carbon atoms in the main chain substituted by an alkyl group having 1 or more and 5 or less carbon atoms, wherein these alkyl groups optionally have at least one group selected from the group consisting of a hydroxyl group, a mercapto group, an amino group and a carboxyl group as a substituent. 6 . The electrophotographic photosensitive member according to claim 5 , wherein the content of the compound α is 3.5% by mass or more and 15% by mass or less relative to the compound represented by the formula (B1) or (B2).

7. A process cartridge comprising: The electrophotographic photosensitive member according to any one of claims 1 to 6; and at least one unit selected from the group consisting of a charging unit, a developing unit, and a cleaning unit, the process cartridge being detachably mountable to a main body of the electrophotographic apparatus.

8. An electronic photographic device comprising: The electrophotographic photosensitive member according to any one of claims 1 to 6; and a charging unit, an exposure unit, a developing unit, and a transfer unit.

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