Electrophotographic receptor, process cartridge, and electrophotographic device

Abstract

To provide an electrophotographic receptor capable of suppressing an increase in residual potential even when used repeatedly.SOLUTION: An electrophotographic receptor includes a support and a photosensitive layer. The photosensitive layer contains two kinds of benzimidazole perylene compounds as an electron transport material.SELECTED DRAWING: None

Description

[Technical field]

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

[0002] Currently, electrophotographic photoreceptors that are mounted in process cartridges and electrophotographic devices are mainly electrophotographic photoreceptors that contain an organic photoconductive substance (organic electrophotographic photoreceptor, hereinafter also referred to as "photoreceptor"). Electrophotographic photoreceptors that use an organic photoconductive substance have advantages such as non-pollution, high productivity, and ease of material design. An electrophotographic photoreceptor generally has a support and a photosensitive layer formed on the support. In addition, an intermediate layer is often provided between the support and the photosensitive layer in order to suppress charge injection from the support side to the photosensitive layer side and to suppress the occurrence of image defects such as black spots. In addition, an undercoat layer such as a conductive layer may be provided between the support and the intermediate layer. In recent years, the sensitivity of charge generating materials has increased, and the amount of generated charges has increased. This has led to a problem that the generated charges tend to remain in the charge generating layer. As a technique for suppressing such residual charges in the charge generating layer, a technique is known in which an intermediate layer contains an electron transport material to facilitate smooth transfer of electrons from the charge generating layer side to the support side. However, due to the increased speed of electrophotographic processes and the longer life of cartridges, the performance required of photoconductors is becoming more advanced, and there are cases where the movement of electrons is insufficient. For this reason, technological development is being carried out to improve the intermediate layer. Patent Document 1 discloses a technique of incorporating a naphthaleneimide compound in an intermediate layer, and Patent Document 2 discloses a technique of incorporating a perinone compound in an intermediate layer. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2014-215477 A [Patent Document 2] JP 2020-46640 A Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, there has been an ever-increasing demand for faster image output and longer cartridge life, and accordingly, there is a demand for photoreceptors that can provide stable image output even when used repeatedly for a long period of time. As a result of studies by the present inventors, it has been found that there is room for improvement in the techniques disclosed in Patent Documents 1 and 2 in terms of the increase in residual potential during long-term repeated use. An object of the present invention is to provide an electrophotographic photosensitive member capable of suppressing an increase in residual potential during long-term repeated use and enabling stable image output, as well as a process cartridge and an electrophotographic apparatus having the electrophotographic photosensitive member. [Means for solving the problem]

[0005] The electrophotographic photoreceptor according to the present invention comprises a support and a photosensitive layer provided on the support, The photosensitive layer is characterized in that it contains, as an electron transport material, a benzimidazoperylene compound represented by the following formula (1) and a benzimidazoperylene compound represented by the following formula (2). [ka] [ka] (In formulas (1) and (2), R 11 ~R 18 and R 21 ~R 28are each independently a group selected from the group consisting of a hydrogen atom, a substituted or unsubstituted alkyl group having from 1 to 7 carbon atoms, a halogen atom, a cyano group, a nitro group, a hydroxyl group, a carboxyl group, a methoxy group, an alkoxycarbonyl group, and an amino group, and the substituent of the substituted alkyl group is a fluorine atom. However, when the substituted or unsubstituted alkyl group is an alkyl group having a branched chain, the number of carbon atoms in the branched chain is from 1 to 2. R 11 and R 12 , R 12 and R 13 and R 13 and R 14 may each independently be linked to each other to form an aromatic ring. 15 and R 16 , R 16 and R 17 and R 17 and R 18 may each independently be linked to each other to form an aromatic ring. 21 and R 22 , R 22 and R 23 and R 23 and R 24 may each independently be linked to each other to form an aromatic ring. 25 and R 26 , R 26 and R 27 and R 27 and R 28 may each independently be linked to each other to form an aromatic ring. X 11 ~X 18 and X 21 ~X 28 each independently represents a hydrogen atom, a halogen atom, a cyano group, or a nitro group. According to another aspect of the present invention, there is provided a process cartridge which integrally supports the above-mentioned electrophotographic photosensitive member and at least one means selected from the group consisting of a charging means, a developing means, and a cleaning means, and is detachably mountable to the main body of the electrophotographic apparatus. According to another aspect of the present invention, there is provided an electrophotographic apparatus having the above electrophotographic photoreceptor, a charging means, an exposing means, a developing means and a transferring means. Effect of the Invention

[0006] According to the present invention, it is possible to provide an electrophotographic photoreceptor capable of suppressing an increase in residual potential even during long-term repeated use and capable of stable image output, as well as a process cartridge and an electrophotographic apparatus having the electrophotographic photoreceptor. [Brief description of the drawings]

[0007] [Figure 1] 1 is a diagram showing a schematic configuration of an example of an electrophotographic apparatus having a process cartridge equipped with an electrophotographic photosensitive member according to the present invention. [Diagram 2] FIG. 2 is a diagram showing an example of a layer structure of an electrophotographic photoreceptor according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] The electrophotographic photoreceptor according to the present invention comprises a support and a photosensitive layer provided on the support, and is characterized in that the photosensitive layer contains, as an electron transport material, a benzimidazoperylene compound represented by the following formula (1) and a benzimidazoperylene compound represented by the following formula (2).

[0009] -Benzimidazoperylene compound represented by formula (1) and benzimidazoperylene compound represented by formula (2)- [ka] [ka] In formulas (1) and (2), R 11 ~R 18 and R 21 ~R 28are each independently a group selected from the group consisting of a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 7 carbon atoms, a halogen atom, a cyano group, a nitro group, a hydroxy group, a carboxy group, a methoxy group, an alkoxycarbonyl group, and an amino group, and the substituent of the substituted alkyl group is a fluorine atom. However, when the substituted or unsubstituted alkyl group is an alkyl group having a branched chain, the number of carbon atoms in the branched chain is 1 to 2. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. R 11 and R 12 , R 12 and R 13 and R 13 and R 14 may each independently be linked to each other to form an aromatic ring. 15 and R 16 , R 16 and R 17 and R 17 and R 18 may each independently be linked to each other to form an aromatic ring. 21 and R 22 , R 22 and R 23 and R 23 and R 24 may each independently be linked to each other to form an aromatic ring. 25 and R 26 , R 26 and R 27 and R 27 and R 28 may each independently be linked to each other to form an aromatic ring. X 11 ~X 18 and X 21 ~X 28 each independently represents a hydrogen atom, a halogen atom, a cyano group, or a nitro group. Examples of the halogen atom include a chlorine atom and a bromine atom.

[0010] In order to further suppress the decrease in photosensitivity and the increase in residual potential that occur when images are repeatedly formed, the benzimidazoperylene compound represented by the formula (1) and the benzimidazoperylene compound represented by the formula (2) may further include a compound represented by the formula (3), 11 and R 21 , R12 and R 22 , R 13 and R 23 , R 14 and R 24 , R 15 and R 25 , R 16 and R 26 , R 17 and R 27 and R 18 and R 28 are preferably the same.

[0011] Specific examples of the benzimidazoperylene compound represented by formula (1) and the benzimidazoperylene compound represented by formula (2) are shown below, but the present embodiment is not limited thereto.

[0012] [Table 1]

[0013] In the photosensitive layer, the content ratio by mass of the benzimidazoperylene compound represented by formula (1) and the benzimidazoperylene compound represented by formula (2) is preferably 1:2 to 2:1 (benzimidazoperylene compound represented by formula (1):benzimidazoperylene compound represented by formula (2)).

[0014] The present inventors speculate that the reason why the photosensitive layer having the above-mentioned structure can suppress an increase in residual potential even during repeated use over a long period of time is as follows. Benzimidazoperylene compounds have a large π-conjugated skeleton and high electron transfer ability, so that delay in electron transfer, which is the cause of residual potential, is unlikely to occur in the early stages. However, the residual potential increases during long-term use. The reason for this is that in the process of repeated electron transfer, a crystal structure change occurs due to stabilization of the molecular existence state, which becomes an inhibiting factor (trap site) for electron transfer, and is considered to be one of the causes of the increase in residual potential. Therefore, the present inventors have conducted extensive research and found that by using a mixture of cis / trans isomers of a benzimidazoperylene compound represented by formula (1) and a benzimidazoperylene compound represented by formula (2), it is possible to suppress the increase in residual potential even during long-term use. The present inventors believe that the reason for this is that the existence state of the molecules is stable due to the presence of a mixture of cis / trans isomers, and therefore structural changes can be suppressed.

[0015] [Electrophotographic photoreceptor] The electrophotographic photoreceptor according to the present invention includes a support and a photosensitive layer provided on the support. Fig. 2 is a diagram showing an example of the layer structure of an electrophotographic photoreceptor. In Fig. 2, a support 101, a conductive layer 102 on the support 101, an electron transport layer 103 on the conductive layer 102, a charge generation layer 104 on the electron transport layer 103, and a hole transport layer 105 on the charge generation layer 104 are formed. That is, in Fig. 2, the electrophotographic photoreceptor has the support 101, the conductive layer 102, the electron transport layer 103, the charge generation layer 104, and the hole transport layer 105 in this order. In the electrophotographic photoreceptor according to the present invention, the photosensitive layer may be composed of a laminated type photosensitive layer having an electron transport layer, a charge generation layer, and a hole transport layer. The photosensitive layer may also be composed of an electron transport layer and a layer containing a charge generation material and a hole transport material. Furthermore, the photosensitive layer may be composed of a single-layer type photosensitive layer containing an electron transport material, a charge generation material, and a hole transport material. Generally, a cylindrical electrophotographic photoreceptor is widely used, but other shapes such as a belt shape and a sheet shape are also possible.

[0016] <Support> The support is preferably conductive (conductive support). For example, a support made of a metal or alloy such as aluminum, nickel, copper, gold, or iron can be used. In addition, the conductive support may be a support in which a thin film of a conductive material such as a metal or metal oxide is formed on an insulating support. For example, a support in which a thin film of a metal such as aluminum, silver, or gold is formed on an insulating support such as polyester resin, polycarbonate resin, polyimide resin, or glass, or a support in which a thin film of a conductive material such as indium oxide or tin oxide is formed can be used. The surface of the support may be subjected to electrochemical treatment such as anodization, wet honing treatment, blasting treatment, or cutting treatment in order to improve electrical characteristics or suppress interference fringes.

[0017] <Conductive layer> In the present invention, a conductive layer may be provided on the support. By providing the conductive layer, scratches and irregularities on the surface of the support can be concealed and light reflection on the surface of the support can be controlled. The conductive layer preferably contains conductive particles and a resin. The conductive particles may be made of a material such as metal oxide, metal, or carbon black. Examples of metal oxides include zinc oxide, aluminum oxide, indium oxide, silicon oxide, zirconium oxide, tin oxide, titanium oxide, magnesium oxide, antimony oxide, bismuth oxide, etc. Examples of metals include aluminum, nickel, iron, nichrome, copper, zinc, silver, etc. Among these, it is preferable to use metal oxides as the conductive particles, and it is particularly preferable to use titanium oxide, tin oxide, or zinc oxide. When a metal oxide is used as the conductive particles, the surface of the metal oxide may be treated with a silane coupling agent or the like, or the metal oxide may be doped with an element such as phosphorus or aluminum or an oxide thereof. The conductive particles may have a laminated structure having a core particle and a coating layer that covers the core particle. Examples of the core particle include titanium oxide, barium sulfate, zinc oxide, etc. Examples of the coating layer include metal oxides such as tin oxide. Furthermore, when a metal oxide is 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. 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.

[0018] The conductive layer can be formed, for example, by preparing a coating solution for a conductive layer containing the above-mentioned materials and solvent, forming a coating film of this, and drying it. Examples of the solvent used in the coating solution for a 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 the dispersion method for dispersing the conductive particles in the coating solution for a conductive layer include a method using a paint shaker, a sand mill, a ball mill, and a liquid collision type high-speed disperser. The average thickness of the conductive layer is preferably from 1 μm to 50 μm, and particularly preferably from 3 μm to 40 μm.

[0019] <Photosensitive layer> The photosensitive layer of the electrophotographic photoreceptor according to the present invention contains a benzimidazoperylene compound represented by formula (1) and a benzimidazoperylene compound represented by formula (2) as electron transport materials.

[0020] -Laminated photosensitive layer- The laminated photosensitive layer may be a photosensitive layer comprising an electron transport layer, a charge generation layer disposed on the electron transport layer, and a hole transport layer disposed on the charge generation layer, or a photosensitive layer comprising an electron transport layer and a layer containing a charge generation material and a hole transport material. It is preferable that the photosensitive layer comprises an electron transport layer disposed on a support, and the electron transport layer contains a benzimidazoperylene compound represented by formula (1) and a benzimidazoperylene compound represented by formula (2). It is also preferable that the photosensitive layer comprises a charge generation layer disposed on the electron transport layer, and a hole transport layer disposed on the charge generation layer.

[0021] (electron transport layer) The electron transport layer contains a benzimidazoperylene compound represented by formula (1) and a benzimidazoperylene compound represented by formula (2). The electron transport layer preferably further contains a polyurethane resin, and may contain metal oxide particles and other additives. A preferred total content of the benzimidazoperylene compound represented by formula (1) and the benzimidazoperylene compound represented by formula (2) relative to the total solid content of the electron transport layer is shown below. From the viewpoint of controlling the volume resistivity of the electron transport layer within a preferred range and from the viewpoint of film formability, the total content is preferably from 30 mass % to 90 mass %, more preferably from 40 mass % to 80 mass %, and even more preferably from 50 mass % to 70 mass %.

[0022] -Polyurethane resin- Polyurethane resins are generally synthesized by a polyaddition reaction between a polyfunctional isocyanate and a polyol. Examples of polyfunctional isocyanates include methylene diisocyanate, ethylene diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, 1,4-cyclohexane diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 1,3-xylylene diisocyanate, 1,5-naphthalene diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, 3,3'-diisocyanate, Examples of the polyfunctional isocyanate include diisocyanates such as methyl-4,4'-diphenylmethane diisocyanate, 3,3'-dimethylbiphenylene diisocyanate, 4,4'-biphenylene diisocyanate, dicyclohexylmethane diisocyanate, and methylene bis(4-cyclohexyl isocyanate); isocyanurates obtained by trimerizing the above diisocyanates; and blocked isocyanates obtained by blocking the isocyanate groups of the above diisocyanates with a blocking agent. One type of polyfunctional isocyanate may be used, or two or more types may be used in combination. Examples of polyols include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 2,3-butanediol, 2,2-dimethyl-1,3-propanediol, 1,2-pentanediol, 1,4-pentanediol, 1,5-pentanediol, 2,4-pentanediol, 3,3-dimethyl-1,2-butanediol, 2-ethyl-2-methyl-1,3-propanediol, 1,2-hexanediol, 1,5-hexanediol, 1,6-hexanediol, 2,5-hexanediol, 2-methyl-2,4-pentanediol, 2,2-diethyl-1,3-propanediol, 2,4-dimethyl-2,4-pentanediol, Examples of diols include hexanediol, 1,7-heptanediol, 2-methyl-2-propyl-1,3-propanediol, 2,5-dimethyl-2,5-hexanediol, 2-ethyl-1,3-hexanediol, 1,2-octanediol, 1,8-octanediol, 2,2,4-trimethyl-1,3-pentanediol, 1,4-cyclohexanedimethanol, hydroquinone, diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol, polyethylene glycol, polypropylene glycol, poly(oxytetramethylene) glycol, 4,4'-dihydroxy-diphenyl-2,2-propane, and 4,4'-dihydroxyphenyl sulfone. Further examples of the polyol include polyester polyol, polycarbonate polyol, polycaprolactone polyol, polyether polyol, polyvinyl butyral, and the like. The polyol may be used alone or in combination of two or more kinds.

[0023] The electron transport layer may contain a resin other than the polyurethane resin as a binder resin, such as a polyvinyl alcohol resin, a polyvinyl acetal resin, a casein resin, a polyamide resin, a cellulose resin, gelatin, a polyester resin, an unsaturated polyester resin, a methacrylic resin, an acrylic resin, a polyvinyl chloride resin, a polyvinyl acetate resin, a vinyl chloride-vinyl acetate-maleic anhydride resin, a silicone resin, a silicone-alkyd resin, a urea resin, a phenol resin, a phenol-formaldehyde resin, a melamine resin, an alkyd resin, or an epoxy resin. The binder resin contained in the electron transport layer is preferably a polyurethane resin in an amount of 80% by mass to 100% by mass, more preferably 90% by mass to 100% by mass, and even more preferably 95% by mass to 100% by mass.

[0024] A preferred mass ratio of the total content of the benzimidazoperylene compound represented by formula (1) and the benzimidazoperylene compound represented by formula (2) contained in the electron transport layer to the content of the polyurethane resin contained in the electron transport layer is as follows: The total content of the benzimidazoperylene compound represented by formula (1) and the benzimidazoperylene compound represented by formula (2):polyurethane resin=40:60 to 80:20 is preferred, and 50:50 to 70:30 is more preferred.

[0025] -Organic acid metal salts and organometallic complexes- The electron transport layer may contain at least one of an organic acid metal salt and an organic metal complex. At least one of the organic acid metal salt and the organic metal complex contained in the electron transport layer may be, for example, an organic acid metal salt or an organic metal complex that acts as a urethane curing catalyst (i.e., a catalyst for a polyaddition reaction between a polyfunctional isocyanate and a polyol) when forming the electron transport layer. Examples of the metal constituting the organic acid metal salt or the organic metal complex include bismuth, aluminum, zirconium, zinc, cobalt, iron, nickel, copper, tin, platinum, palladium, etc. The organic acid of the organic acid metal salt is preferably a monovalent carboxylic acid, and the monovalent carboxylic acid is preferably octylic acid, naphthenic acid or salicylic acid, and more preferably octylic acid.

[0026] As at least one of the organic acid metal salts and organic metal complexes contained in the electron transport layer, from the viewpoint of suppressing an increase in residual potential that occurs during repeated image formation, the following are preferred. At least one of the organic acid metal salts and organic metal complexes containing a metal selected from the group consisting of bismuth, aluminum, zirconium, zinc, cobalt, iron, nickel, and copper is preferred. Furthermore, at least one of the organic acid metal salts and organic metal complexes containing a metal selected from the group consisting of bismuth, aluminum, and zirconium is more preferred. Examples of the organic acid metal salt or organometallic complex containing bismuth include bismuth octylate, bismuth naphthenate, bismuth salicylate; and K-KAT XK-640 manufactured by King Industries. Examples of the organic acid metal salt or organometallic complex containing aluminum include aluminum octylate, aluminum naphthenate, aluminum salicylate; K-KAT5218 manufactured by King Industries; and the like. Examples of the zirconium-containing organic acid metal salt or organometallic complex include zirconium octylate, zirconium naphthenate, zirconium salicylate; K-KAT4205, K-KAT6212, and K-KATA209 manufactured by King Industries. Examples of the zinc-containing organic acid metal salt or organometallic complex include zinc octylate, zinc naphthenate, and zinc salicylate. Examples of the cobalt-containing organic acid metal salt or organometallic complex include cobalt octylate, cobalt naphthenate, and cobalt salicylate. Examples of the iron-containing organic acid metal salt or organometallic complex include iron octylate, iron naphthenate, and iron salicylate. Examples of the nickel-containing organic acid metal salt or organometallic complex include nickel octylate, nickel naphthenate, and nickel salicylate. Examples of the copper-containing organic acid metal salt or organometallic complex include copper octylate, copper naphthenate, and copper salicylate. The organic acid metal salts and organometallic complexes may be used alone or in combination of two or more kinds. When the electron transport layer contains at least one of an organic acid metal salt and an organic metal complex, the total content of the organic acid metal salt and the organic metal complex relative to the total solid content of the electron transport layer is preferably 0.001% by mass to 3% by mass, more preferably 0.003% by mass to 2% by mass, even more preferably 0.01% by mass to 1% by mass, and even more preferably 0.05% by mass to 0.5% by mass.

[0027] -Metal oxide particles- The electron transport layer preferably contains metal oxide particles from the viewpoint of suppressing leakage caused by the penetration of foreign matter into the photoreceptor. Examples of the metal oxide particles include strontium titanate particles, zinc oxide particles, titanium oxide particles, tin oxide particles, zirconium oxide particles, etc., and strontium titanate particles, zinc oxide particles, titanium oxide particles, or tin oxide particles are preferred. The volume average particle size of the metal oxide particles is preferably 10 nm or more and 2000 nm or less, more preferably 50 nm or more and 1000 nm or less, and even more preferably 60 nm or more and 500 nm or less. The specific surface area of ​​metal oxide particles measured by the BET method is 10 m 2 / g or more is preferred. The metal oxide particles may be surface-treated. Examples of the surface treatment agent for the metal oxide particles include a silane coupling agent, a titanate coupling agent, an aluminum coupling agent, a surfactant, etc. The metal oxide particles may be a mixture of two or more types of metal oxide particles having different metal species, metal oxide particles having different surface treatments, or metal oxide particles having different particle sizes. When the electron transport layer contains metal oxide particles for the purpose of suppressing leakage caused by the penetration of foreign matter into the photoreceptor, the content of the metal oxide particles relative to the total solid content of the electron transport layer is preferably 1% by mass or more and less than 30% by mass, more preferably 5% by mass or more and 25% by mass or less, and even more preferably 10% by mass or more and 20% by mass or less.

[0028] The electron transport layer may contain various additives for improving electrical characteristics, environmental stability, and image quality. Examples of the additives include known materials such as polycyclic condensation and azo electron transport pigments, zirconium chelate compounds, titanium chelate compounds, aluminum chelate compounds, titanium alkoxide compounds, organic titanium compounds, silane coupling agents, etc. As described above, silane coupling agents are used for surface treatment of inorganic particles, and may be further added as an additive to the electron transport layer. Examples of silane coupling agents as additives include vinyltrimethoxysilane, 3-methacryloxypropyl-tris(2-methoxyethoxy)silane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, vinyltriacetoxysilane, 3-mercaptopropyltrimethoxysilane, and 3-chloropropyltrimethoxysilane. Examples of the zirconium chelate compound include zirconium butoxide, zirconium ethyl acetoacetate, acetylacetonate zirconium butoxide, ethyl acetoacetate zirconium butoxide, zirconium acetate, zirconium oxalate, zirconium lactate, zirconium phosphonate, zirconium octanoate, zirconium naphthenate, zirconium laurate, zirconium stearate, zirconium isostearate, methacrylate zirconium butoxide, stearate zirconium butoxide, and isostearate zirconium butoxide. Examples of titanium chelate compounds include tetraisopropyl titanate, tetra-n-butyl titanate, butyl titanate dimer, tetra(2-ethylhexyl) titanate, titanium acetylacetonate, polytitanium acetylacetonate, titanium octylene glycolate, titanium lactate ammonium salt, titanium lactate, titanium lactate ethyl ester, and polyhydroxytitanium stearate. Examples of aluminum chelate compounds include aluminum isopropylate, monobutoxyaluminum diisopropylate, aluminum butyrate, diethylacetoacetate aluminum diisopropylate, and aluminum tris(ethylacetoacetate). These additives may be used alone or as a mixture or polycondensation product of a plurality of compounds.

[0029] Resin particles or the like may be added to the electron transport layer to adjust the surface roughness. Examples of the resin particles include silicone resin particles and crosslinked polymethyl methacrylate resin particles. The surface of the electron transport layer may be polished to adjust the surface roughness. Examples of the polishing method include buffing, sandblasting, wet honing, and grinding. The formation of the electron transport layer is not particularly limited, and a known formation method can be used. For example, the electron transport layer can be formed by forming a coating film of a coating solution for the electron transport layer in which the above-mentioned components are added to a solvent, drying the coating film, and heating it as necessary. Examples of the solvent for preparing the coating liquid for the electron transport layer include known organic solvents, such as alcohol-based solvents, aromatic hydrocarbon solvents, halogenated hydrocarbon solvents, ketone-based solvents, ketone alcohol-based solvents, ether-based solvents, and ester-based solvents. Specific examples of these solvents include ordinary organic solvents such as methanol, ethanol, n-propanol, iso-propanol, n-butanol, benzyl alcohol, methyl cellosolve, ethyl cellosolve, acetone, methyl ethyl ketone, cyclohexanone, methyl acetate, ethyl acetate, n-butyl acetate, dioxane, tetrahydrofuran, methylene chloride, chloroform, chlorobenzene, and toluene. The benzimidazoperylene compound represented by formula (1) and the benzimidazoperylene compound represented by formula (2) are preferably dispersed in an organic solvent since they are difficult to dissolve in an organic solvent. Examples of the dispersion method include known methods such as a roll mill, a ball mill, a vibration ball mill, an attritor, a sand mill, a colloid mill, and a paint shaker. When metal oxide particles are blended in the electron transport layer, the metal oxide particles are also preferably dispersed in an organic solvent by the same dispersion method. Examples of the method for applying the coating solution for the electron transport layer include ordinary methods such as blade coating, wire bar coating, spray coating, dip coating, bead coating, air knife coating, and curtain coating. The thickness of the electron transport layer is preferably 3 μm or more, more preferably 5 μm or more, from the viewpoint of leak resistance, and is preferably 50 μm or less, more preferably 40 μm or less, and even more preferably 30 μm or less, from the viewpoint of suppressing an increase in residual potential during repeated use.

[0030] (Charge generation layer) The charge generating layer preferably contains a charge generating substance and a binder resin. Examples of the charge generating material include azo pigments, perylene pigments, anthraquinone derivatives, anthranthrone derivatives, dibenzpyrenequinone derivatives, pyranthrone derivatives, quinone pigments, indigoid pigments, phthalocyanine pigments, and perinone pigments. Among these, phthalocyanine pigments are preferred. Among phthalocyanine pigments, oxytitanium phthalocyanine, chlorogallium phthalocyanine, and hydroxygallium phthalocyanine are preferred. Examples of the binder resin include polymers and copolymers of vinyl compounds such as styrene, vinyl acetate, vinyl chloride, acrylic acid esters, methacrylic acid esters, vinylidene fluoride, and trifluoroethylene, polyvinyl alcohol resins, polyvinyl acetal resins, polycarbonate resins, polyester resins, polysulfone resins, polyphenylene oxide resins, polyurethane resins, cellulose resins, phenolic resins, melamine resins, silicon resins, and epoxy resins. Among these, polyester resins, polycarbonate resins, and polyvinyl acetal resins are preferred. In the charge generating layer, the ratio of the charge generating substance to the binder resin (charge generating substance / binder resin) is preferably in the range of 10 / 1 to 1 / 10, and more preferably in the range of 5 / 1 to 1 / 5, on a mass basis. The method for forming the charge generation layer can be the same as that for the electron transport layer, and can be carried out, for example, by forming a coating film of a coating liquid for the charge generation layer in which the above components are added to a solvent, drying the coating film, and heating it if necessary. Examples of the solvent used in the coating liquid for the charge generating layer include alcohol-based solvents, ketone-based solvents, ether-based solvents, ester-based solvents, and aromatic hydrocarbon solvents. The thickness of the charge generating layer is preferably from 0.05 μm to 5 μm.

[0031] (Hole transport layer) The hole transport layer preferably contains a hole transport substance and a binder resin. Examples of hole transporting materials include hydrazone compounds, styryl compounds, benzidine compounds, butadiene compounds, enamine compounds, triarylamine compounds, and triphenylamines. Also included are polymers having groups derived from these compounds in the main chain or side chain. Examples of binder resins include polyester resins, polycarbonate resins, polymethacrylic acid ester resins, polyarylate resins, polysulfone resins, and polystyrene resins. Among these, polycarbonate resins and polyarylate resins are preferred. The viscosity average molecular weight of these resins is preferably in the range of 5,000 to 150,000. In the hole transport layer, the ratio of the hole transport substance to the binder resin (hole transport substance / binder resin) is preferably in the range of 10 / 5 to 5 / 10, and more preferably in the range of 10 / 8 to 6 / 10, on a mass basis. The method for forming the hole transport layer can be the same as that for the electron transport layer or the charge generation layer, and can be carried out, for example, by forming a coating film of a coating solution for the hole transport layer in which the above-mentioned components are added to a solvent, drying the coating film, and heating it as necessary. Examples of the solvent used in the coating liquid for the hole transport layer include alcohol-based solvents, ketone-based solvents, ether-based solvents, ester-based solvents, and aromatic hydrocarbon solvents. The thickness of the hole transport layer is preferably 5 μm or more and 40 μm or less.

[0032] (Layer Containing Charge-Generating Material and Hole-Transporting Material) When a photosensitive layer is formed by providing an electron transport layer and a layer containing a charge generating substance and a hole transporting substance, the materials contained in the layer containing the charge generating substance and the hole transporting substance can be the same as the materials described above in the (charge generating layer) and (hole transporting layer). When a photosensitive layer is formed by providing an electron transport layer and a layer containing a charge generating material and a hole transport material, the content of the charge generating material in the photosensitive layer is preferably 0.1% by mass to 10% by mass, more preferably 0.8% by mass to 5% by mass, based on the total solid content. The content of the hole transport material in the photosensitive layer is preferably 5% by mass to 50% by mass, based on the total solid content. The method for forming a layer containing a charge generating substance and a hole transporting substance can be the same as that described above, and can be carried out, for example, by forming a coating film of a coating liquid for a layer containing a charge generating substance and a hole transporting substance, drying the coating film, and heating it as necessary.

[0033] -Single-layer photosensitive layer- The single-layer photosensitive layer is a photosensitive layer that contains an electron transport material, a charge generating material, a hole transport material, and, if necessary, a binder resin and other known additives in the same layer. The materials of the single-layer photosensitive layer can be the same as those described above for the (electron transport layer), (charge generating layer), and (hole transport layer). The preferred total content of the benzimidazoperylene compound represented by formula (1) and the benzimidazoperylene compound represented by formula (2) in the single-layer photosensitive layer is as follows: It is preferably from 10 to 200 parts by mass, more preferably from 10 to 100 parts by mass, and particularly preferably from 10 to 75 parts by mass, relative to 100 parts by mass of the binder resin contained in the photosensitive layer. The content of the charge generating material in the single-layer photosensitive layer is preferably 0.1% by mass to 10% by mass, more preferably 0.8% by mass to 5% by mass, based on the total solid content. The content of the hole transport material in the single-layer photosensitive layer is preferably 5% by mass to 50% by mass, based on the total solid content. The method for forming a single-layer type photosensitive layer can be the same as the method for forming a multi-layer type photosensitive layer, and can be carried out, for example, by forming a coating film of a coating solution for a photosensitive layer in which materials are added to a solvent, drying the coating film, and heating it as necessary. The thickness of the single-layer photosensitive layer is, for example, 5 μm or more and 50 μm or less, and preferably 10 μm or more and 40 μm or less.

[0034] <Other layers> A protective layer may be provided on the photosensitive layer. In the case of a laminated photosensitive layer having an electron transport layer, a charge generating layer, and a hole transport layer, a protective layer containing conductive particles or a hole transport substance and a binder resin may be provided on the hole transport layer. The protective layer may further contain an additive such as a lubricant. The binder resin of the protective layer itself may have electrical conductivity or hole transport properties, and in that case, the protective layer may not contain conductive particles or hole transport substances other than the binder resin. The binder resin of the protective layer may be a thermoplastic resin or a curable resin that is cured by heat, light, radiation (electron beam, etc.), or the like.

[0035] [Process cartridge and electrophotographic device] The process cartridge according to the present invention is characterized in that it integrally supports the above-mentioned electrophotographic photosensitive member and at least one means selected from the group consisting of charging means, developing means, and cleaning means, and is detachably mountable to the main body of an electrophotographic apparatus. Also, the electrophotographic apparatus according to the present invention is characterized in that it has the above-mentioned electrophotographic photosensitive member, charging means, exposure means, developing means, and transfer means.

[0036] FIG. 1 shows a schematic configuration of an example of an electrophotographic apparatus having a process cartridge equipped with an electrophotographic photosensitive member according to the present invention. In FIG. 1, a cylindrical electrophotographic photosensitive member 1 is rotated around an axis 2 in the direction of an arrow at a predetermined peripheral speed. The surface (peripheral surface) of the electrophotographic photosensitive member 1 that is rotated is charged to a predetermined positive or negative potential by a charging means 3 (e.g., a contact charger, a non-contact charger, etc.). Next, it is exposed to exposure light (image exposure light) 4 from an exposure means (not shown) such as slit exposure or laser beam scanning exposure. In this way, electrostatic latent images corresponding to a target image are sequentially formed on the surface of the electrophotographic photosensitive member 1. The electrostatic latent image formed on the surface of the electrophotographic photoreceptor 1 is then developed into a toner image by the toner contained in the developer of the developing means 5. The toner images formed and carried on the surface of the electrophotographic photoreceptor 1 are successively transferred to a transfer material (such as paper) P by a transfer bias from a transfer means (such as a transfer roller) 6. The transfer material P is fed from a transfer material supplying means (not shown) to between the electrophotographic photoreceptor 1 and the transfer means 6 (contact portion) in synchronization with the rotation of the electrophotographic photoreceptor 1. After the toner image is transferred, the transfer material P is separated from the surface of the electrophotographic photosensitive member 1 and introduced into fixing means 8 where the image is fixed, and is printed out of the apparatus as an image-formed product (print, copy). After the toner image is transferred, the surface of the electrophotographic photoreceptor 1 is cleaned by removing the residual developer (residual toner) by cleaning means (cleaning blade, etc.) 7. Then, the surface is neutralized by pre-exposure light (not shown) from a pre-exposure means (not shown), and is then used repeatedly for image formation. Note that, as shown in FIG. 1, when the charging means 3 is a contact charging means using a charging roller, pre-exposure is not necessarily required. The electrophotographic photosensitive member 1 and at least one member selected from the group consisting of the charging means 3, the developing means 5 and the cleaning means 7 may be housed in a container and supported as a process cartridge, and the process cartridge may be configured to be detachably attached to the main body of the electrophotographic apparatus. In Fig. 1, the electrophotographic photosensitive member 1, the charging means 3, the developing means 5 and the cleaning means 7 are supported as a cartridge, and the process cartridge 9 is detachably attached to the main body of the electrophotographic apparatus by using a guide means 10 such as a rail of the main body of the electrophotographic apparatus. EXAMPLES

[0037] The present invention will be described in more detail below with reference to examples. In the examples, "parts" means "parts by mass".

[0038] Example 1 <Manufacture of electrophotographic photoreceptor> (Formation of Electron Transport Layer) 20 parts by mass of blocked isocyanate (Sumidur BL3175, manufactured by Sumitomo Bayern Urethane Co., Ltd., solid content 75% by mass) and 7.5 parts by mass of butyral resin (S-LEC BL-1, manufactured by Sekisui Chemical Co., Ltd.) were dissolved in 150 parts by mass of methyl ethyl ketone. 34 parts by mass of a mixture (mass ratio 1:1) of exemplary compound (1-1) as a benzimidazoperylene compound represented by formula (1) and exemplary compound (2-1) as a benzimidazoperylene compound represented by formula (2) were mixed into this solution. Then, dispersion was performed for 10 hours in a sand mill using glass beads with a diameter of 1 mm to obtain a dispersion liquid. 0.005 parts by mass of bismuth carboxylate (K-KAT XK-640, manufactured by King Industries Co., Ltd.) and 2 parts by mass of silicone resin particles (Tospearl 145, manufactured by Momentive Performance Materials Co., Ltd.) were added to this dispersion liquid to obtain a coating liquid for an electron transport layer. This coating liquid for the electron transport layer was dip-coated onto a cylindrical aluminum substrate having a diameter of 30 mm, and dried and cured at 160° C. for 60 minutes to form an electron transport layer having a thickness of 7 μm.

[0039] (Formation of Charge Generation Layer) Hydroxygallium phthalocyanine was prepared as a charge generating material, which has diffraction peaks at Bragg angles (2θ±0.2°) of at least 7.3°, 16.0°, 24.9°, and 28.0° in the X-ray diffraction spectrum using Cukα characteristic X-rays. A mixture of 15 parts by mass of hydroxygallium phthalocyanine, 10 parts by mass of vinyl chloride-vinyl acetate copolymer resin (VMCH, manufactured by Nippon Unicar Co., Ltd.), and 200 parts by mass of n-butyl acetate was dispersed in a sand mill using glass beads with a diameter of 1 mm for 4 hours. 175 parts by mass of n-butyl acetate and 180 parts by mass of methyl ethyl ketone were added to the obtained dispersion and stirred to obtain a coating liquid for a charge generating layer. This coating liquid for a charge generating layer was dip-coated on the electron transport layer and dried at 150°C for 15 minutes to form a charge generating layer with a thickness of 0.2 μm.

[0040] (Formation of Hole Transport Layer) The following materials were prepared: 38 parts by weight of a compound represented by the following formula (HT-1) as a hole transport material 10 parts by weight of a compound represented by the following formula (HT-2) as a hole transport material Polycarbonate resin (A) (viscosity average molecular weight 46,000) 52 parts by weight The above materials were added to 800 parts by mass of tetrahydrofuran and dissolved, and 8 parts by mass of tetrafluoroethylene resin (Lubron L5, Daikin Industries, average particle size 300 nm) was added. The above mixture was dispersed for 2 hours at 5500 rpm using a homogenizer (Ultra Turrax, IKA) to obtain a coating liquid for a hole transport layer. This coating liquid for a hole transport layer was dip-coated on the charge generation layer and dried at 140°C for 40 minutes to form a hole transport layer with a thickness of 29 μm. The above process resulted in the electrophotographic photoreceptor of Example 1. [ka] [ka]

[0041] (Examples 2 to 11) A photoreceptor was prepared in the same manner as in Example 1, except that in forming the electron transport layer, the types and amounts of the benzimidazoperylene compound represented by formula (1) and the benzimidazoperylene compound represented by formula (2) were changed as shown in Table 2. The positions of the substituents in the benzimidazoperylene compound represented by formula (1) and the benzimidazoperylene compound represented by formula (2) in Examples 4 to 7 are shown below. In Example 4, the position of the substituent (-CH3) in the exemplary compound (1-4) is R 12 and R 17 In addition, the position of the substituent (-CH3) in the exemplary compound (2-4) is R 22 and R 27 It is. In Example 5, the position of the substituent (-COOCH3) in the exemplary compound (1-5) is R 12 and R 17 In addition, the position of the substituent (-COOCH3) in the exemplary compound (2-5) is R 22 and R 27 It is. In Example 6, the position of the substituent (-COOH) in the exemplary compound (1-6) is R 12 and R 17 In addition, the position of the substituent (-COOH) in the exemplary compound (2-6) is R 22 and R 27 It is. In Example 7, the position of the substituent (-Cl) in the exemplary compound (1-7) is R 12 and R 17 In addition, the position of the substituent (-Cl) in the exemplary compound (2-7) is R 22 and R 27 It is.

[0042] (Examples 12 to 15) A photoreceptor was prepared in the same manner as in Example 1, except that 15 parts by mass of each of the metal particles shown in Table 2 was added to the coating liquid for the electron transport layer. The strontium titanate particles used in Example 12 had a volume average particle size of 100 nm (SW-100, manufactured by Titanium Kogyo). The zinc oxide particles used in Example 13 are as follows: Surface-untreated zinc oxide particles (volume average particle size: 70 nm, specific surface area: 15 m 2 / g, MZ-150, manufactured by Teika) surface-treated with a silane coupling agent (3-methacryloxypropylmethyldiethoxysilane, KBE-502, manufactured by Shin-Etsu Chemical Co., Ltd.). The titanium oxide particles used in Example 14 had a volume average particle size of 30 nm (TAF-1500J, manufactured by Fuji Titanium Industry Co., Ltd.). The tin oxide particles used in Example 15 had a volume average particle size of 20 nm (S1, manufactured by Mitsubishi Materials).

[0043] Example 16 The following materials were mixed: 1.5 parts by mass of hydroxygallium phthalocyanine having diffraction peaks at Bragg angles (2θ±0.2°) of at least 7.3°, 16.0°, 24.9°, and 28.0° in an X-ray diffraction spectrum using CuKα characteristic X-rays as a charge generating substance 19 parts by weight of a compound represented by formula (ET-1) as an electron transport material - 49.5 parts by weight of polycarbonate resin (Z) (viscosity average molecular weight 50,000) as binder resin 30 parts by weight of a compound represented by formula (HT-2) as a hole transport material Silicone oil KP340 (Shin-Etsu Chemical Co., Ltd.) 0.001 mass 200 parts by weight of tetrahydrofuran 100 parts by weight of monochlorobenzene This mixture was dispersed in a high-pressure homogenizer to obtain a coating solution for a layer containing a charge generating material and a hole transporting material. The obtained coating solution for the layer containing the charge generating substance and the hole transporting substance was dip-coated on an electron transporting layer formed on a cylindrical aluminum substrate having a diameter of 30 mm in the same manner as in Example 1, and dried at 140°C for 1 hour to form a layer containing the charge generating substance and the hole transporting substance and having a thickness of 26 μm. [ka]

[0044] (Examples 17 to 20) A photoreceptor was prepared in the same manner as in Example 16, except that the types and amounts of the benzimidazoperylene compound represented by formula (1) and the benzimidazoperylene compound represented by formula (2) were changed as shown in Table 2. The positions of the substituents in the benzimidazoperylene compound represented by formula (1) and the benzimidazoperylene compound represented by formula (2) in Examples 19 and 20 are shown below. In Example 19, the position of the substituent (-CH3) in the exemplary compound (1-4) is R 12 and R 17 In addition, the position of the substituent (-CH3) in the exemplary compound (2-4) is R 22 and R 27 It is. In Example 20, the position of the substituent (-COOCH3) in the exemplary compound (1-5) is R 12 and R 17 In addition, the position of the substituent (-COOCH3) in the exemplary compound (2-5) is R 22and R 27 It is.

[0045] Example 21 The following materials were mixed: 2 parts by mass of hydroxygallium phthalocyanine having diffraction peaks at Bragg angles (2θ±0.2°) of at least 7.3°, 16.0°, 24.9°, and 28.0° in an X-ray diffraction spectrum using CuKα characteristic X-rays as a charge generating substance 13 parts by weight of a compound represented by (ET-1) as an electron transport material 2.5 parts by mass of exemplary compound (1-1) as the benzimidazoperylene compound represented by formula (1) 2.5 parts by mass of exemplary compound (2-1) as a benzimidazoperylene compound represented by formula (2) - 49 parts by weight of polycarbonate resin (A) (viscosity average molecular weight 46,000) as binder resin 200 parts by weight of tetrahydrofuran 100 parts by weight of monochlorobenzene This mixture was dispersed in a sand mill using glass beads with a diameter of 1 mm for 6 hours. 31 parts by mass of the compound represented by formula (HT-2) as a hole transport material and 0.001 parts by mass of silicone oil KP340 (manufactured by Shin-Etsu Chemical Co., Ltd.) were added to the resulting dispersion, and the mixture was stirred overnight to obtain a coating solution for the photosensitive layer. The photosensitive layer coating solution obtained above was applied onto a cylindrical aluminum substrate having a diameter of 30 mm by dip coating, and dried at 140° C. for 1 hour to form a photosensitive layer having a thickness of 26 μm.

[0046] Comparative Example 1 A photoreceptor was prepared in the same manner as in Example 1, except that the following was used as the coating liquid for the electron transport layer. 20 parts by mass of blocked isocyanate (Sumidur BL3175, manufactured by Sumitomo Bayern Urethane Co., Ltd., solid content 75% by mass) and 7.5 parts by mass of butyral resin (S-LEC BL-1, manufactured by Sekisui Chemical Co., Ltd.) were dissolved in 150 parts by mass of methyl ethyl ketone. 34 parts by mass of a mixture (mass ratio 1:1) of a compound represented by formula (ET-2) and a compound represented by formula (ET-3) as an electron transport material were mixed into this solution, and the mixture was dispersed for 10 hours in a sand mill using glass beads with a diameter of 1 mm to obtain a dispersion. 0.005 parts by mass of bismuth carboxylate (K-KAT XK-640, manufactured by King Industries Co., Ltd.) and 2 parts by mass of silicone resin particles (Tospearl 145, manufactured by Momentive Performance Materials Co., Ltd.) were added to this dispersion to obtain a coating solution for an electron transport layer. [ka] [ka]

[0047] Comparative Example 2 The coating solution for the layer containing the charge generating material and the hole transporting material of Example 16 was dip-coated on an electron transporting layer formed on a cylindrical aluminum substrate having a diameter of 30 mm in the same manner as in Comparative Example 1, and dried at 140°C for 1 hour to form a layer containing the charge generating material and the hole transporting material with a thickness of 26 µm.

[0048] Comparative Example 3 The following materials were mixed: 2 parts by mass of hydroxygallium phthalocyanine having diffraction peaks at Bragg angles (2θ±0.2°) of at least 7.3°, 16.0°, 24.9°, and 28.0° in an X-ray diffraction spectrum using CuKα characteristic X-rays as a charge generating substance 5 parts by weight of a compound represented by formula (ET-4) as an electron transport material - 49 parts by weight of polycarbonate resin (A) (viscosity average molecular weight 46,000) as binder resin 200 parts by weight of tetrahydrofuran 100 parts by weight of monochlorobenzene This mixture was dispersed in a sand mill using glass beads with a diameter of 1 mm for 6 hours. 31 parts by mass of the compound represented by formula (HT-2) as a hole transport material and 0.001 parts by mass of silicone oil KP340 (manufactured by Shin-Etsu Chemical Co., Ltd.) were added to the resulting dispersion, and the mixture was stirred overnight to obtain a coating solution for the photosensitive layer. The photosensitive layer coating solution obtained above was applied onto a cylindrical aluminum substrate having a diameter of 30 mm by dip coating, and dried at 140° C. for 1 hour to form a photosensitive layer having a thickness of 26 μm. [ka] The type and amount of the electron transport material used in the comparative examples are shown in Table 3. In Table 3, for Comparative Example 1 and Comparative Example 2, the type and amount of the electron transport material contained in the electron transport layer are shown.

[0049] <Photoreceptor performance evaluation> The photoreceptor of each Example or Comparative Example was mounted on a laser beam printer (product name: LBP-2510) manufactured by Canon Inc., which was modified, and the following performance evaluations were carried out under an environment of a temperature of 23° C. and a humidity of 50% RH. The evaluation results are shown in Tables 2 and 3.

[0050] [Charge retention] The surface potential probe of a surface potential meter (Trek 334, manufactured by Trek Corporation) was placed at a position 1 mm away from the surface of the photoreceptor. The surface of the photoreceptor was charged to -700 V, and the potential drop (dark decay) after 0.1 seconds was measured.

[0051] [Suppression of increase in residual potential] The surface potential probe of a surface potential meter (Trek 334, manufactured by Trek Corporation) was placed at a position 1 mm away from the surface of the photoreceptor. After charging the surface of the photoconductor to -700 V, monochromatic light with a wavelength of 780 nm (half-width 20 nm, light intensity 1.5 μJ / cm 2 ) was exposed to light (exposure time 80 ms). The surface potential (residual potential) was measured 330 ms after the start of exposure. The above measurements were carried out after continuously printing 20,000 sheets and 40,000 sheets of A4 paper with a density of 20%. The residual potential difference was calculated by subtracting the residual potential before printing from the residual potential after printing, and the residual potential increase was calculated.

[0052] [Table 2]

[0053] [Table 3]

[0054] Embodiments of the present disclosure include the following configurations and methods. (Configuration 1) A support and a photosensitive layer provided on the support, The photosensitive layer of the electrophotographic photoreceptor contains, as an electron transport material, a benzimidazoperylene compound represented by the following formula (1) and a benzimidazoperylene compound represented by the following formula (2). [ka] [ka] (In formulas (1) and (2), R 11 ~R 18 and R 21 ~R 28 are each independently a group selected from the group consisting of a hydrogen atom, a substituted or unsubstituted alkyl group having from 1 to 7 carbon atoms, a halogen atom, a cyano group, a nitro group, a hydroxyl group, a carboxyl group, a methoxy group, an alkoxycarbonyl group, and an amino group, and the substituent of the substituted alkyl group is a fluorine atom. However, when the substituted or unsubstituted alkyl group is an alkyl group having a branched chain, the number of carbon atoms in the branched chain is from 1 to 2. R 11 and R 12 , R 12 and R 13 and R 13 and R 14 may each independently be linked to each other to form an aromatic ring.15 and R 16 , R 16 and R 17 and R 17 and R 18 may each independently be linked to each other to form an aromatic ring. 21 and R 22 , R 22 and R 23 and R 23 and R 24 may each independently be linked to each other to form an aromatic ring. 25 and R 26 , R 26 and R 27 and R 27 and R 28 may each independently be linked to each other to form an aromatic ring. X 11 ~X 18 and X 21 ~X 28 each independently represents a hydrogen atom, a halogen atom, a cyano group, or a nitro group. (Configuration 2) In the benzimidazoperylene compound represented by the formula (1) and the benzimidazoperylene compound represented by the formula (2), R 11 and R 21 , R 12 and R 22 , R 13 and R 23 , R 14 and R 24 , R 15 and R 25 , R 16 and R 26 , R 17 and R 27 and R 18 and R 28 and (Configuration 3) 3. The electrophotographic photoreceptor according to Structure 1 or 2, wherein the photosensitive layer comprises an electron transport layer disposed on the support, and the electron transport layer contains the benzimidazoperylene compound represented by Formula (1) and the benzimidazoperylene compound represented by Formula (2). (Configuration 4) 4. The electrophotographic photoreceptor according to claim 3, wherein the photosensitive layer comprises a charge generating layer disposed on the electron transport layer, and a hole transport layer disposed on the charge generating layer. (Configuration 5) 5. The electrophotographic photoreceptor according to Configuration 3 or 4, wherein the electron transport layer contains a polyurethane resin. (Configuration 6) The electrophotographic photoreceptor according to any one of Configurations 3 to 5, wherein the electron transport layer contains at least one kind of metal oxide particles selected from the group consisting of strontium titanate particles, zinc oxide particles, titanium oxide particles, and tin oxide particles. (Configuration 7) 7. The electrophotographic photoreceptor according to any one of Configurations 1 to 6, wherein the content ratio by mass of the benzimidazoperylene compound represented by Formula (1) to the benzimidazoperylene compound represented by Formula (2) in the photosensitive layer is the benzimidazoperylene compound represented by Formula (1):the benzimidazoperylene compound represented by Formula (2)=1:2 to 2:1. (Configuration 8) A process cartridge which integrally supports the electrophotographic photosensitive member according to any one of Configurations 1 to 7 and at least one means selected from the group consisting of a charging means, a developing means, and a cleaning means, and is detachably mountable to a main body of an electrophotographic apparatus. (Configuration 9) An electrophotographic apparatus comprising the electrophotographic photoreceptor according to any one of Configurations 1 to 7, a charging means, an exposing means, a developing means and a transferring means. [Explanation of symbols]

[0055] 1. Electrophotographic photoreceptor 2-axis 3. Charging means 4 Exposure light 5. Developing method 6 Transfer Method 7 Cleaning Method 8 Fixing Method 9 Process cartridge 10 Guidance means P Transfer material

Claims

1. It comprises a support and a photosensitive layer provided on the support, An electrophotographic photoreceptor in which the photosensitive layer contains a benzimidazoperylene compound represented by the following formula (1) and a benzimidazoperylene compound represented by the following formula (2) as electron transport materials. 【Chemistry 1】 【Chemistry 2】 (In formulas (1) and (2), R ２６ ~R １８ and R ２１ ~R ２８ are each independently a group selected from the group consisting of a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 7 carbon atoms, a halogen atom, a cyano group, a nitro group, a hydroxy group, a carboxy group, a methoxy group, an alkoxycarbonyl group, and an amino group, and the substituent of the substituted alkyl group is a fluorine atom. However, when the substituted or unsubstituted alkyl group is a branched alkyl group, the number of carbon atoms in the branched chain is 1 or more and 2 or less. R １１ and R １２ , R １２ and R １３ and R １３ and R １４ may each independently be linked to each other to form an aromatic ring. R １５ and R １６ , R １６ and R １７ and R １７ and R １８ may each independently be linked to each other to form an aromatic ring. R ２１ and R ２２ , R ２２ and R ２３ and R ２３ and R ２４ may each independently be linked to each other to form an aromatic ring. R ２５ and R ２６ , R ２６ and R ２７ and R ２７ and R ２８ may each independently be linked to each other to form an aromatic ring. X １１ ~X １８ and X ２１ ~X ２８ Each of these independently represents a hydrogen atom, a halogen atom, a cyano group, or a nitro group.

2. In the benzimidazoperylene compound represented by formula (1) and the benzimidazoperylene compound represented by formula (2), R １１ and R ２１ , R １２ and R ２２ , R １３ and R ２３ , R １４ and R ２４ , R １５ and R ２５ , R １６ and R ２６ , R １７ and R ２７ and R １８ and R ２８ The electrophotographic photoreceptor according to claim 1, wherein each of the elements is the same.

3. The electrophotographic photoreceptor according to claim 1, wherein the photosensitive layer comprises an electron transport layer disposed on the support, and the electron transport layer contains a benzimidazoperylene compound represented by formula (1) and a benzimidazoperylene compound represented by formula (2).

4. The electrophotographic photoreceptor according to claim 3, wherein the photosensitive layer comprises a charge generating layer disposed on the electron transport layer and a hole transport layer disposed on the charge generating layer.

5. The electrophotographic photoreceptor according to claim 3, wherein the electron transport layer contains a polyurethane resin.

6. The electrophotographic photoreceptor according to claim 3, wherein the electron transport layer contains at least one metal oxide particle selected from the group consisting of strontium titanate particles, zinc oxide particles, titanium oxide particles, and tin oxide particles.

7. The electrophotographic photoreceptor according to claim 1, wherein the mass-based content ratio of the benzimidazoperylene compound represented by formula (1) and the benzimidazoperylene compound represented by formula (2) in the photosensitive layer is benzimidazoperylene compound represented by formula (1):benzimidazoperylene compound represented by formula (2) = 1:2 to 2:

1.

8. A process cartridge characterized by integrally supporting an electrophotographic photoreceptor according to any one of claims 1 to 7 and at least one means selected from the group consisting of a charging means, a developing means, and a cleaning means, and being detachably attached to the body of an electrophotographic apparatus.

9. An electrophotographic photoreceptor according to any one of claims 1 to 7, and an electrophotographic apparatus having a charging means, an exposure means, a developing means and a transfer means.

Images