JP2019095642A - Electrophotographic photoreceptor, process cartridge and electrophotographic device - Google Patents

Abstract

To provide an electrophotographic photoreceptor which achieves both excellent durability and scratch resistance.SOLUTION: An electrophotographic photoreceptor has a surface layer containing a charge transport substance, a polyester resin having a specific structure and alumina particles having a volume average particle size of 10 nm or more and 200 nm or less.SELECTED DRAWING: None

Description

  The present invention relates to an electrophotographic photosensitive member, a process cartridge, and an electrophotographic apparatus.

  In the electrophotographic process, in recent years, miniaturization of the electrophotographic apparatus and increase in the number of printable sheets are desired. Correspondingly, the electrophotographic photosensitive member is required to have durability against electric and mechanical external force. Therefore, methods using a photosensitive member having a surface layer using a polyester resin having excellent mechanical strength and methods using a photosensitive member having a surface layer to which particles are added have been studied (Patent Documents 1 and 2).

  Patent Document 1 discloses a photoreceptor in which the dispersion stability of the inorganic fine particles is improved by using a polyester resin having diphenyl ether dicarboxylic acid, and the durability and the scratch resistance are improved. Patent Document 2 discloses a photosensitive member whose durability is improved by using a polyester resin having a branched chain.

JP 2007-108239 A JP 2005-189716 A

  However, the electrophotographic photosensitive members using the conventional polyester resin and the inorganic fine particles described in Patent Document 1 and Patent Document 2 described above are not sufficient in abrasion resistance and scratch resistance to the level required in recent years. Furthermore, when alumina particles are contained in the surface layer, the film may become brittle, the particles may be removed, and the abrasion resistance and the scratch resistance may be deteriorated due to the generation of scratches. there were.

  Accordingly, an object of the present invention is to provide an electrophotographic photosensitive member having both excellent durability and scratch resistance. Another object of the present invention is to provide a process cartridge and an electrophotographic apparatus using such an electrophotographic photosensitive member.

  The electrophotographic photosensitive member of the present invention has a surface layer containing a charge transport substance and a polyester resin, and the surface layer contains alumina particles having a volume average particle diameter of 10 nm or more and 200 nm or less, and the polyester resin , A structure represented by the general formula (I) and a structure represented by the general formula (II), and a structure represented by the general formula (II) is a structure represented by the general formula (II-1) and the general formula It is characterized by having a structure shown by (II-3).

(In the general formula (I), X ¹ represents a divalent group.)

(In the general formula (II), X ² represents a single bond, an oxygen atom, an alkylidene group or a cycloalkylidene group. R ^{11 to} R ¹⁸ each independently represent a hydrogen atom or an alkyl group.)

(In General Formula (II-1), R ²¹ represents a hydrogen atom, a methyl group, an ethyl group or a phenyl group. R ²² and R ²³ each independently represent an alkyl group having 1 to 4 carbon atoms. R ²⁴ to R ²⁷ are each independently, .m represents a hydrogen atom or a methyl group, an integer of 0 to 3.)

(In General Formula (II-3), R ^{41 to} R ⁴⁴ each independently represent a hydrogen atom or a methyl group.)

  Further, the process cartridge of the present invention integrally supports the above-described electrophotographic photosensitive member and at least one device selected from the group consisting of a charging device, a developing device, a transferring device and a cleaning device, and an electrophotographic apparatus main body It is characterized by being detachable.

  An electrophotographic apparatus according to the present invention is characterized by including the above-described electrophotographic photosensitive member, charging unit, exposure unit, developing unit, and transfer unit.

  According to the present invention, it is possible to provide an electrophotographic photosensitive member having both excellent durability and scratch resistance, and a process cartridge and an electrophotographic apparatus using such an electrophotographic photosensitive member.

FIG. 2 is a view showing an example of a schematic configuration of an electrophotographic apparatus provided with a process cartridge.

  The electrophotographic photosensitive member of the present invention has a surface layer containing a charge transport material, a polyester resin, and alumina particles. Then, the polyester resin is represented by the general formula (II) having a structure represented by the general formula (I), a structure represented by the general formula (II-1) and a structure represented by the general formula (II-3) And the alumina particles have a volume average particle size of 10 nm or more and 200 nm or less.

(In the general formula (I), X ¹ represents a divalent group.)

(In the general formula (II), X ² represents a single bond, an oxygen atom, an alkylidene group or a cycloalkylidene group. R ^{11 to} R ¹⁸ each independently represent a hydrogen atom or an alkyl group.)

(In General Formula (II-1), R ²¹ represents a hydrogen atom, a methyl group, an ethyl group or a phenyl group. R ²² and R ²³ each independently represent an alkyl group having 1 to 4 carbon atoms. R ²⁴ to R ²⁷ are each independently, .m represents a hydrogen atom or a methyl group, represents a repeating number in parentheses is an integer of 0-3.)

(In General Formula (II-3), R ^{41 to} R ⁴⁴ each independently represent a hydrogen atom or a methyl group.)

  The present inventors speculate as follows about the reason why the electrophotographic photosensitive member satisfying such characteristics is compatible with the excellent durability and the scratch resistance. In order to achieve both excellent wear resistance and scratch resistance, it is important to be able to sufficiently hold alumina particles, but the present inventors have improved elasticity by the structure represented by the general formula (II-3). Since it becomes strong against an external force and the entanglement is further improved by the structure represented by the general formula (II-1), it is presumed that the retention ability of alumina particles is enhanced.

<Polyester resin>
In the present invention, the polyester resin has a structure represented by the general formula (I) and a structure represented by the general formula (II-1) and a structure represented by the general formula (II-3) And the structure shown.

  In the present invention, the copolymerization form of the polyester resin may be any form such as block copolymerization, random copolymerization, alternating copolymerization and the like. Among them, random copolymers are preferable in that high abrasion resistance and scratch resistance can be obtained.

  With respect to the content of the polyester resin in the surface layer, the content of alumina particles is preferably 0.2% by mass or more and 20% by mass or less, and is 0.5% by mass or more and 15% by mass or less More preferably, it is particularly preferably 1% by mass or more and 10% by mass or less.

(1) Structure Represented by General Formula (I) In the present invention, as a structure represented by General Formula (I) possessed by the polyester resin, terephthalic acid, isophthalic acid, biphenyl dicarboxylic acid, aliphatic dicarboxylic acid, naphthalene dicarboxylic acid And structures derived from carboxylic acids such as Specifically, the following structures may be mentioned.

Among these, it is preferable to have a structure represented by the formula (I-1) in view of wear resistance and scratch resistance.

  The proportion of the structure represented by the formula (I-1) in the structure represented by the general formula (I) is preferably 65 mol% or more.

  When the polyester resin further has a structure represented by the general formula (I) other than the structure represented by the formula (I-1), having a structure represented by the general formula (I-2) Particularly preferred in view of the properties and scratch resistance.

(2) Structure Shown by General Formula (II) (2-1) Structure Shown by General Formula (II-1) Specific examples of the structure shown by General Formula (II-1) are shown below.

Above all, the structure represented by the formula (II-1-1) is preferable in terms of achieving both high durability and scratch resistance.

  The proportion of the structure represented by General Formula (II-1) in the structure represented by General Formula (II) is preferably 35 mol% or more and 65 mol% or less. By satisfying the ratio, the degree of freedom of the polyester resin is increased, and the entanglement of the structure represented by the general formula (II-1) when alumina particles are contained is further exhibited, and the abrasion resistance and the scratch resistance are improved. I guess it will improve better.

(2-2) Structure Shown by General Formula (II-3) Specific examples of the structure shown by General Formula (II-3) are shown below.

Among them, the structure represented by the formula (II-3-3) is preferable in terms of achieving both high durability and scratch resistance.

  The proportion of the structure represented by the formula (II-3) in the structure represented by the general formula (II) is preferably 35 mol% or more and 80 mol% or less. Furthermore, by satisfying the ratio, the elasticity of the polyester resin is improved, and it is estimated that the abrasion resistance and the scratch resistance are improved by strengthening against the external force when the alumina particles are contained. .

(2-3) Other Structures The structure represented by the general formula (II) has a structure represented by the general formula (II-1) or any other structure than the structure represented by the general formula (II-3) It is good. As another structure, the following structures are mentioned, for example.

<Binder resin other than polyester resin>
The surface layer may use another resin as the binder resin in addition to the polyester resin. Specifically, polycarbonate resin, polymethacrylic acid ester resin, polysulfone resin, polystyrene resin and the like can be mentioned. Other resins may be blended or copolymerized with one another. When using other resin, it is preferable that the mass of the polyester resin in this invention is 80 mass% or more with respect to the total mass of all the binding resin. 40,000 or more and 200,000 or less are preferable, and, as for the weight average molecular weight of a polyester resin, 70,000 or more and 120,000 or less are more preferable. At this time, the weight average molecular weight of resin is a weight average molecular weight of polystyrene conversion measured by the method of Unexamined-Japanese-Patent No. 2007-79555.

<Alumina particles>
The electrophotographic photosensitive member of the present invention contains, in the surface layer thereof, alumina particles having a volume average particle diameter of 10 nm or more and 200 nm or less. Such alumina particles include, for example, synthetic alumina. The synthetic alumina may, for example, be a thermal decomposition method of aluminum alum, a thermal decomposition method of aluminum carbonate, an aqueous spark discharge method of aluminum, a hydrolysis method of aluminum alkoxide, or a gas phase oxidation method. Among them, alumina particles by a vapor phase oxidation method are preferable in terms of electrical characteristics. Moreover, when using an alumina particle, the alumina which reduced impurities, such as an acid and an alkali, by refinement | purification etc. is preferable.

  The volume average particle diameter of the alumina particles is required to be 10 nm or more and 200 nm or less in order to achieve abrasion resistance and scratch resistance when contained in the polyester resin of the present invention. By setting the volume average particle diameter to 10 nm or more and 200 nm or less, it is presumed that the alumina particles are firmly held in the surface layer by the polyester resin of the present invention. The reason why the alumina particles are supposed to be held firmly by using the alumina particles is that the density of the alumina particles is high, that they are high hardness particles, and the surface condition peculiar to alumina is in the polyester resin of the present invention. It is presumed that it is involved in the dispersed state.

  Furthermore, the volume average particle size of the alumina particles is preferably 10 nm or more and 150 nm or less, more preferably 20 nm or more and 100 nm or less, and particularly preferably 20 nm or more and 50 nm or less.

  In the present invention, the method of measuring the volume average particle size of alumina particles is as follows. Alumina particles are separated from the layer, 100 primary particles of the alumina particles are observed at 100,000 times by SEM (scanning microscope), and the longest diameter and the shortest diameter of each primary particle are measured. Measure the equivalent sphere diameter. The 50% diameter (D50v) in the cumulative frequency of the obtained sphere equivalent diameter is determined, and this is taken as the volume average particle diameter of alumina particles.

  The particle size distribution of alumina particles has a volume distribution cumulative value of not more than 1/2 volume diameter of the volume average particle diameter of 10 volume% or less, and a volume distribution of 2 volume diameter or more of the volume average particle diameter of 10 volume% or less The particle size distribution of

The alumina particles of the present invention are preferably surface-treated in terms of dispersibility and electrical properties.
As the surface treatment, a surface treatment with a surface treatment agent such as a coupling agent with a silane coupling agent or a titanium coupling agent is preferable. The surface treatment amount of the surface treatment agent is preferably 0.1% by mass or more and 20% by mass or less of the alumina particles.

  Surface treating agents include epoxysilanes such as vinyltrimethoxysilane and vinyltriethoxysilane, epoxysilanes such as 3-glycidoxypropylpetyldimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, Styrylsilanes such as styryltrimethoxysilane, methacrylsilanes such as 3-methacryloxypropylmethyldimethoxysilane, acrylic silanes such as 3-acryloxypropylmethoxysilane, methyltrimethoxysilane, dimethyldimethoxysilane, hexyltriethoxysilane, octyltriethoxysilane Examples include alkoxysilanes such as ethoxysilane, silazanes such as hexamethyl silazane, and silicone oil.

  Among these, surface treatment with a compound represented by the following general formula (IV-1) or (IV-2) is preferable in terms of abrasion resistance, scratch resistance and electrical properties. It is speculated that this is because interaction occurs between the polyester resin of the present invention and the epoxy group on the surface of the alumina particles.

(In formula (IV-1), R ⁵¹ represents a methyl group, a methoxy group or an alkyl group. R ⁵² and R ⁵³ each independently represent a methyl group or an ethyl group.)

(In formula (IV-2), R ⁶¹ represents a methyl group, a methoxy group or an alkyl group. R ⁶² and R ⁶³ each independently represent a methyl group or an ethyl group.)

  As a surface treating agent shown by General formula (IV-1), 2- (3, 4- epoxycyclohexyl) ethyl trimethoxysilane is mentioned.

  As the surface treatment agent represented by the general formula (IV-2), 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltrithiol Ethoxysilane is mentioned.

[Electrophotographic photosensitive member]
The electrophotographic photosensitive member of the present invention has a surface layer containing a charge transport material and a polyester resin. Furthermore, it is preferable to have a support and a photosensitive layer. The photosensitive layer of the electrophotographic photosensitive member is mainly classified into (1) laminated type photosensitive layer and (2) single layer type photosensitive layer. (1) The laminate type photosensitive layer has a charge generation layer containing a charge generation substance and a charge transport layer containing a charge transport substance. (2) The single-layer type photosensitive layer has a photosensitive layer containing both the charge generating substance and the charge transporting substance. In the present invention, (1) in the case of the laminated photosensitive layer, the surface layer containing the charge transport substance is the charge transport layer, and (2) in the case of the single layer photosensitive layer, the surface layer containing the charge transport substance Is the photosensitive layer.

As a method of producing an electrophotographic photosensitive member, there may be mentioned a method of preparing a coating solution for each layer to be described later, applying the solution in the order of desired layers and drying it. At this time, as a coating method of the coating liquid, a dip coating method, a spray coating method, a curtain coating method, a spin coating method and the like can be mentioned. Among these, the dip coating method is preferable from the viewpoint of efficiency and productivity.
Each layer will be described below.

<Conductive layer>
In the present invention, a conductive layer may be provided on the support. By providing the conductive layer, it is possible to conceal scratches and irregularities on the surface of the support and to control the reflection of light on the surface of the support.

  The conductive layer preferably contains conductive particles and a resin.

  Examples of the material of the conductive particles include metal oxides, metals, carbon black and the like.

  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 and the like. Examples of the metal include aluminum, nickel, iron, nichrome, copper, zinc, silver and the like. Among these, it is preferable to use a metal oxide as the conductive particles, and in particular, it is more 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 metal oxide may be doped with an element such as phosphorus or aluminum or an oxide thereof. In addition, the conductive particles may have a laminated structure including core material particles and a coating layer that covers the particles. The core particles include titanium oxide, barium sulfate, zinc oxide and the like. The covering layer may, for example, be a metal oxide such as tin oxide. When a metal oxide is used as the conductive particles, the volume average particle diameter is preferably 1 nm or more and 500 nm or less, and more preferably 3 nm or more and 200 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, alkyd resin and the like.

  In addition, the conductive layer may further contain a masking agent such as silicone oil, resin particles, titanium oxide and the like.

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

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

<Subbing layer>
In the present invention, an undercoat layer may be provided on the support or the conductive layer. By providing the undercoat layer, the adhesion function between the layers can be enhanced and the charge injection blocking function can be imparted.

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

  As resin, polyester resin, polycarbonate resin, polyvinyl acetal resin, acrylic resin, epoxy resin, melamine resin, polyurethane resin, phenol resin, polyvinyl phenol resin, alkyd resin, polyvinyl alcohol resin, polyethylene oxide resin, polypropylene oxide resin, polyamide resin And polyamide acid resin, polyimide resin, polyamide imide resin, cellulose resin and the like.

  As a polymerizable functional group which a monomer having a polymerizable functional group has, an isocyanate group, a blocked isocyanate group, a methylol group, an alkylated methylol group, an epoxy group, a metal alkoxide group, a hydroxyl group, an amino group, a carboxyl group, a thiol group, A carboxylic anhydride group, a carbon-carbon double bond group, etc. are mentioned.

  The undercoat layer may further contain an electron transport material, a metal oxide, a metal, a conductive polymer, and the like for the purpose of enhancing the electrical properties. Among these, electron transport substances and metal oxides are preferably used.

  Electron transport materials include quinone compounds, imide compounds, benzimidazole compounds, cyclopentadienylidene compounds, fluorenone compounds, xanthone compounds, benzophenone compounds, cyanovinyl compounds, halogenated aryl compounds, silole compounds, boron compounds and the like. .

  The undercoat layer may be formed as a cured film by copolymerizing with the above-described monomer having a polymerizable functional group, using an electron transport material having a polymerizable functional group as the electron transporting substance.

  Examples of metal oxides include indium tin oxide, tin oxide, indium oxide, titanium oxide, zinc oxide, aluminum oxide, silicon dioxide and the like. Examples of the metal include gold, silver and aluminum.

  The undercoat layer may further contain an additive.

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

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

<Photosensitive layer>
The photosensitive layer of the electrophotographic photosensitive member is mainly classified into (1) laminated type photosensitive layer and (2) single layer type photosensitive layer. (1) The laminated photosensitive layer has a charge generating layer containing a charge generating substance and a charge transporting layer containing a charge transporting substance. (2) The single-layer type photosensitive layer has a photosensitive layer containing both the charge generating substance and the charge transporting substance.

(1) Stacked Photosensitive Layer The stacked photosensitive layer has a charge generation layer and a charge transport layer.

(1-1) Charge Generating Layer The charge generating layer preferably contains a charge generating substance and a resin.

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

  The content of the charge generation material in the charge generation layer is preferably 40% by mass to 85% by mass, and more preferably 60% by mass to 80% by mass, with respect to the total mass of the charge generation layer. preferable.

  As resin, polyester resin, polycarbonate resin, polyvinyl acetal resin, polyvinyl butyral resin, acrylic resin, silicone resin, epoxy resin, epoxy resin, melamine resin, polyurethane resin, phenol resin, polyvinyl alcohol resin, cellulose resin, polystyrene resin, polyvinyl acetate resin And polyvinyl chloride resin. Among these, polyvinyl butyral resin is more preferable.

  The charge generation layer may further contain an additive such as an antioxidant and an ultraviolet light absorber. Specifically, hindered phenol compounds, hindered amine compounds, sulfur compounds, phosphorus compounds, benzophenone compounds and the like can be mentioned.

  The average film thickness of the charge generation 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.

  The charge generation layer can be formed by preparing a coating solution for charge generation layer containing the above-mentioned respective materials and a solvent, forming this coating film, and drying it. Examples of the solvent used for the coating solution include alcohol solvents, sulfoxide solvents, ketone solvents, ether solvents, ester solvents, aromatic hydrocarbon solvents and the like.

The charge transport layer contains a charge transport material and a resin.
Examples of the charge transport material include polycyclic aromatic compounds, heterocyclic compounds, hydrazone compounds, styryl compounds, enamine compounds, benzidine compounds, triarylamine compounds, and resins having a group derived from these materials. Be
Also, the charge transport material may contain a plurality of types together. Hereinafter, specific examples of the charge transport material are shown.

  The content of the charge transport material in the charge transport layer is preferably 20% by mass to 60% by mass, and more preferably 30% by mass to 50% by mass, with respect to the total mass of the charge transport layer. preferable.

  The content ratio (mass ratio) of the charge transport substance to the resin is preferably 4:10 to 20:10, and more preferably 5:10 to 10:10.

  The charge transport layer can be formed by forming a coating of a charge transport layer coating solution prepared by dissolving a charge transport substance and a binder resin in a solvent, and drying the coating. Examples of the solvent used for the coating solution for forming the charge transport layer include alcohol solvents, sulfoxide solvents, ketone solvents, ether solvents, ester solvents, and aromatic hydrocarbon solvents.

The charge transport layer may also contain additives such as an antioxidant, an ultraviolet light absorber, a plasticizer, a leveling agent, a slipperiness imparting agent, and an abrasion resistance improver.
Specifically, 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, boron nitride particles and the like can be mentioned.

  The average 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, and particularly preferably 10 μm or more and 30 μm or less.

  The charge transport layer can be formed by preparing a coating solution for charge transport layer containing the above-described respective materials and a solvent, forming this coating film, and drying it. Examples of the solvent used for the coating solution include alcohol solvents, ketone solvents, ether solvents, ester solvents, and aromatic hydrocarbon solvents. Among these solvents, ether solvents or aromatic hydrocarbon solvents are preferable.

(2) Single-Layer Type Photosensitive Layer A single-layer type photosensitive layer is formed by preparing a coating solution for a photosensitive layer containing a charge generating substance, charge transporting substance, resin and solvent, forming this coating film, and drying it. can do. As the charge generating material, the charge transporting material, and the resin, the same materials as the examples of the materials in the above-mentioned “(1) laminated photosensitive layer” can be used.

<Protective layer>
A protective layer may be provided on the surface layer as long as the effects of the present invention are exhibited. The protective layer preferably contains conductive particles or charge transport materials, and a binder resin. Furthermore, the protective layer may contain an additive such as a lubricant. In addition, the binder resin itself of the protective layer may have conductivity or charge transportability. In that case, the protective layer may not contain the conductive particles and the charge transport substance separately. The binder resin for the protective layer may be a thermoplastic resin or a curable resin obtained by curing with heat, light, radiation (electron beam or the like).

[Process cartridge, electrophotographic apparatus]
The process cartridge of the present invention integrally supports the above-described electrophotographic photosensitive member and at least one unit selected from the group consisting of a charging unit, a developing unit, a transfer unit, and a cleaning unit. It is characterized in that it is detachable from the main body.

  An electrophotographic apparatus according to the present invention is characterized by including the electrophotographic photosensitive member, the charging unit, the exposure unit, the developing unit, and the transfer unit described above.

  FIG. 1 shows an example of a schematic configuration of an electrophotographic apparatus having a process cartridge provided with an electrophotographic photosensitive member.

  In FIG. 1, a cylindrical electrophotographic photosensitive member 1 is rotationally driven around an axis 2 in the direction of the arrow at a predetermined circumferential speed. The surface (peripheral surface) of the electrophotographic photosensitive member 1 which is rotationally driven is uniformly charged to a predetermined positive or negative potential by the charging unit 3 (primary charging unit: charging roller or the like). Next, an exposure (image exposure) 4 from an exposure means (not shown) such as slit exposure or laser beam scanning exposure is received. In this way, electrostatic latent images corresponding to the intended image are sequentially formed on the surface of the electrophotographic photosensitive member 1.

  The electrostatic latent image formed on the surface of the electrophotographic photosensitive member 1 is then developed by the toner contained in the developer of the developing means 5 to form a toner image on the electrophotographic photosensitive member 1. Next, the toner image on the surface of the electrophotographic photosensitive member 1 is sequentially transferred to a transfer material (such as paper) P by a transfer bias from a transfer unit (such as a transfer roller) 6. The toner image on the surface of the electrophotographic photosensitive member 1 may be transferred to a transfer material (such as paper) through an intermediate transfer member. The transfer material P is taken out from the transfer material supply means (not shown) between the electrophotographic photoreceptor 1 and the transfer means 6 (contact part) in synchronization with the rotation of the electrophotographic photoreceptor 1 and fed. Be done.

  The transfer material P to which the toner image has been transferred is separated from the surface of the electrophotographic photosensitive member 1 and introduced into the fixing means 8 and fixed on the toner image to be discharged out of the apparatus as an image formation (print, copy) Be done.

  After the transfer of the toner image, the developer (toner) remaining after transfer is removed from the surface of the electrophotographic photoreceptor 1 by a cleaning means (a cleaning blade or the like) 7. Then, after being subjected to charge removal processing by pre-exposure (not shown) from a pre-exposure means (not shown), it is repeatedly used for image formation. In addition, as shown in FIG. 1, when the charging unit 3 is a contact charging unit such as a charging roller, pre-exposure is not necessarily required.

  Among the components such as the electrophotographic photosensitive member 1, the charging unit 3, the developing unit 5, the transfer unit 6 and the cleaning unit 7, a plurality of components are selected and accommodated in a container to be integrally coupled as a process cartridge. You may Then, the process cartridge may be configured to be detachable from an electrophotographic apparatus main body such as a copying machine or a laser beam printer. In FIG. 1, the electrophotographic photosensitive member 1, the charging unit 3, the developing unit 5, and the cleaning unit 7 are integrally supported to form a cartridge. Then, the process cartridge 9 is detachably mounted on the electrophotographic apparatus main body by using a guide 10 such as a rail of the electrophotographic apparatus main body.

  Hereinafter, the present invention will be described in more detail using examples and comparative examples. The present invention is not limited at all by the following examples unless the gist is exceeded. In the following description of the examples, "part" is on a mass basis unless otherwise noted.

<Synthesis of polyester resin>
Synthesis Example 1
59 g of dicarboxylic acid halide represented by the following formula

Was dissolved in dichloromethane to prepare an acid halide solution. Also, separately, 24.2 g of diol represented by the following formula,

27 g of diol represented by the following formula

Was dissolved in a 10% aqueous solution of sodium hydroxide, tributylbenzylammonium chloride was added as a polymerization catalyst, and the mixture was stirred to prepare a diol compound solution.

  Next, the acid halide solution was added to the diol compound solution while stirring to initiate polymerization. The polymerization was carried out for 3 hours with stirring while maintaining the reaction temperature at 25 ° C. or less. During the polymerization reaction, p-tert-butylphenol was added as a polymerization modifier. Thereafter, the polymerization reaction was terminated by the addition of acetic acid, and washing with water was repeated until the aqueous phase became neutral. After washing, the dichloromethane solution was dropped into methanol under stirring to precipitate a polymer, and this polymer was vacuum dried to obtain 72.3 g of polyester resin A. The obtained polyester resin A has 100 mol% of a structure represented by the formula (I-1) as a structure represented by the formula (I), and has a formula (II-1) as a structure represented by the formula (II) It was a polyester resin having 50 mol% of the structure shown by -1) and 50 mol% of the structure shown by formula (II-3-3). Further, the weight average molecular weight of the obtained polyester resin A was 80,000.

(Composition examples 2 to 14)
Polyester resins B to K and CE-1 to CE-3 shown in Table 1 were produced in the same manner as in the above (Synthesis example 1).

  In Table 1, the weight average molecular weight of resin shows the polystyrene conversion weight average molecular weight (Mw) of polyester resin. Moreover, the number of the parenthesis of the partial structure of resin is a molar ratio. For example, "I-1 / I-2 (70/30)" means that the structures of I-1 and I-2 are 70 mol% and 30 mol%, respectively.

  The proportion of the structure contained in the polyester resin in the surface layer can be analyzed by a general analysis method. Moreover, the content rate of the polyester resin of this invention with respect to the total mass of all the resin in a surface layer can be analyzed by a general analysis method. The following is an example of the analysis method.

  First, the surface layer of the electrophotographic photosensitive member is dissolved with a solvent. Thereafter, the various materials contained in the surface layer are separated by a separation device capable of separating and collecting each component such as size exclusion chromatography or high performance liquid chromatography. The separated polyester resin is subjected to nuclear magnetic resonance spectrum analysis and mass analysis to calculate the number of repetitions and the molar ratio of the structure. Alternatively, it is hydrolyzed in the presence of an alkali or the like to be decomposed into a carboxylic acid moiety and a bisphenol moiety. Nuclear magnetic resonance spectrum analysis and mass analysis are performed on the obtained bisphenol moiety to calculate the number of repetitions and the molar ratio of the structure.

<Production example of surface-treated alumina particles>
(Production Example 1)
100 parts of alumina particles (trade name: Alu 65, manufactured by Nippon Aerosil) in a mixed solvent of 20 parts of water and 600 parts of ethanol, and 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane (KBM-303) as a surface treatment agent 2.5 parts by mass of Shin-Etsu Chemical Co., Ltd., and stirred for 30 minutes. The solvent was removed using an evaporator to obtain surface-treated alumina particles PA.

(Production Example 2)
Add 100 parts of alumina particles (trade name: Alu 65, manufactured by Nippon Aerosil) to a mixed solvent of 20 parts of water and 600 parts of ethanol, and 2.5 parts by mass of 3-gridoxypropylmethyldimethoxysilane as a surface treatment agent, After stirring, the solvent was removed using an evaporator to obtain surface-treated alumina particles PB.

(Production Example 3)
Add 100 parts of alumina particles (trade name: Alu 65, manufactured by Nippon Aerosil) to a mixed solvent of 20 parts of water and 600 parts of ethanol, and 2.5 parts by mass of 3-glycdoxypropyltrimethoxysilane as a surface treatment agent, After stirring, the solvent was removed using an evaporator to obtain surface-treated alumina particles PC.

(Production Example 4)
In a mixed solvent of 20 parts of water and 600 parts of ethanol, 100 parts of alumina particles (trade name: TM-DA, manufactured by Daimei Chemical Industries, Ltd.) and 2.5 parts by mass of 3-glycdoxypropyltrimethoxysilane as a surface treatment agent are added After stirring for 30 minutes, the solvent was removed using an evaporator to obtain surface-treated alumina particles PD.

<Production of electrophotographic photosensitive member>
Example 1
An aluminum cylinder having a diameter of 24 mm and a length of 257 mm was used as a support (conductive support).

Next, 100 parts of zinc oxide particles (specific surface area: 15 m ² / g, average particle size: 70 nm, powder resistance: 3.7 × 10 ⁵ Ω · cm) were stirred and mixed with 500 parts of toluene.
To this was added 1.5 parts of N- (2-aminoethyl) -3-aminopropyltrimethoxysilane (trade name: KBM 603, manufactured by Shin-Etsu Chemical Co., Ltd.) as a silane coupling agent, and the mixture was stirred for 6 hours. Then, toluene was distilled off under reduced pressure and the residue was heated at 140 ° C. for 6 hours for drying to obtain zinc oxide particles surface-treated with a silane coupling agent. Next, 15 parts of butyral resin (trade name: BM-1, manufactured by Sekisui Chemical Co., Ltd.) as a polyol resin and 15 parts of blocked isocyanate (trade name: Desmodur BL 3175/1, manufactured by Sumika Bayern Urethane), methyl ethyl ketone 73 It was dissolved in a mixed solvent of 5 parts / 73.5 parts of 1-butanol. In this solution, 81 parts of zinc oxide particles surface-treated with the above-mentioned silane coupling agent, 0.8 parts of 2,3,4-trihydroxybenzophenone (manufactured by Tokyo Kasei Kogyo Co., Ltd.), and zinc octylate (trade name: Nickaoku) 0.81 parts of Ticks zinc Zn (manufactured by Nippon Chemical Industrial Co., Ltd.) was added, and this was placed in a sand mill using glass beads with a diameter of 0.8 mm, and dispersed for 3 hours under an atmosphere of 23 ± 3 ° C. After dispersion treatment, 0.01 parts of silicone oil (trade name: SH28PA, manufactured by Toray Dow Corning silicone) and 5.6 parts of silicone resin particles (trade name: Tospearl 145, manufactured by GE Toshiba Silicone) are added to the mixture and stirred. Thus, a coating solution for conductive layer was prepared.

  The coating solution for a conductive layer was dip-coated on the support, and the obtained coating film was dried at 150 ° C. for 30 minutes and thermally cured to form a conductive layer having a thickness of 30 μm.

  Next, 8.5 parts of a compound represented by the following formula as a charge transporting substance,

15 parts of blocked isocyanate compound (trade name: SBN-70D, manufactured by Asahi Kasei Chemicals), 0.97 parts of polyvinyl alcohol resin (trade name: KS-5Z, manufactured by Sekisui Chemical Co., Ltd.) as a resin, zinc hexanoate as a catalyst II) (trade name: zinc (II) hexanoate, manufactured by Mitsuwa Chemical Co., Ltd.) and 0.15 part were dissolved in a mixed solvent of 88 parts of 1-methoxy-2-propanol and 88 parts of tetrahydrofuran. In this solution, a silica slurry (product name: IPA-ST-UP, manufactured by Nissan Chemical Industries, solid content concentration: 15 mass%, viscosity: 9 mPa · s) having an average primary particle diameter of 9-15 nm dispersed in isopropyl alcohol Then, 1.8 parts of a nylon screen mesh sheet (product name: N-No. 150T) manufactured by Tokyo Screen Co., Ltd. was added and stirred for 1 hour. Thereafter, pressure filtration was carried out using a Teflon filter (product name: PF020) manufactured by ADVANTEC to prepare a coating solution for undercoat layer.

  The undercoat layer coating solution is dip-coated on the conductive layer, and the obtained coating film is heated at 170 ° C. for 20 minutes to cure (polymerize), whereby the film thickness is 0.7 μm or less on the conductive layer. A pull layer was formed.

  Next, 2 parts of polyvinyl butyral (trade name: SLEC BX-1, manufactured by Sekisui Chemical Co., Ltd.) was dissolved in 100 parts of cyclohexanone. To this solution was added 4 parts of hydroxygallium phthalocyanine crystal (charge generating substance) having a strong peak at 7.4 ° and 28.1 ° of Bragg angle 2θ ± 0.2 ° in CuKα characteristic X-ray diffraction. . This was placed in a sand mill using glass beads with a diameter of 1 mm, and dispersed for 1 hour in an atmosphere of 23 ± 3 ° C. After the dispersion treatment, 100 parts of ethyl acetate was added thereto to prepare a coating solution for charge generation layer.

  The coating solution for charge generation layer was dip-coated on the undercoat layer, and the obtained coating film was dried at 90 ° C. for 10 minutes to form a charge generation layer having a thickness of 0.20 μm.

Next, 1 part of alumina particles (trade name: AluC 805, manufactured by Nippon Aerosil) was added to a solution of 19 parts of cyclopentanone and dispersed for 2 hours using an ultrasonic disperser to obtain 10 parts of an alumina dispersion. .
Next, 7 parts of a compound (charge transport material) represented by the formula (CTM-1), 1 part of a compound (charge transport material) represented by the formula (CTM-2), and the polyester resin (A) synthesized in Synthesis Example 1 10 parts were dissolved in a mixed solution of 40 parts of dimethoxymethane and 50 parts of cyclopentanone, and 10 parts of alumina dispersion was added to prepare a coating liquid for charge transport layer.

  The coating solution for charge transport layer was dip-coated on the charge generation layer, and the obtained coated film was dried at 125 ° C. for 40 minutes to form a charge transport layer having a thickness of 14 μm.

(Examples 2 to 34, Comparative Examples 1 to 9)
An electrophotographic photosensitive member was manufactured in the same manner as in Example 1 except that the polyester resin and the charge transport material were changed as shown in Table 2 above (Example 1).
AluC 805 described for the alumina particles used in Table 2: Alumina particles surface-treated with an alkylsilyl group (trade name: AluC 805, manufactured by Nippon Aerosil)
Alu 65: Alumina particles not surface-treated (trade name: Alu 65, manufactured by Nippon Aerosil)
Alu130: Alumina particles not surface-treated (trade name: Alu130, manufactured by Nippon Aerosil)
TM-DA: Alumina particles not surface-treated (trade name: TM-DA, Daimei Chemical Industries)
TM-5D: Alumina particles not surface-treated (trade name: TM-5D, Daimei Chemical Industries)
AA-03: Alumina particles (trade name: Sumicorundum AA-03, manufactured by Sumitomo Chemical Co., Ltd.)
AA-05: Alumina particles (trade name: Sumikorand AA-05, manufactured by Sumitomo Chemical Co., Ltd.)
SA32: Alumina particles not surface-treated (trade name: SA32, manufactured by Nippon Light Metal Co., Ltd.)
PA, PB, PC, PD: alumina particles PA, PB, PC, PD manufactured above

[Evaluation]
<Evaluation of wear resistance>
As an evaluation apparatus, a laser printer (Color LaseJet Enterprise M553) manufactured by Hewlett Packard (38 sheets per minute) was used. The evaluation was performed under a temperature of 15 ° C. and a humidity of 10% RH. Image output is performed in an intermittent mode in which it stops once every two sheets of image output using A4 size plain paper, and after 10,000 images are output, from the initial stage of the surface of the central portion of the electrophotographic photosensitive member The reduction amount of the film thickness of the charge transport layer was evaluated. The measurement of the film thickness in that case was performed by Fisher film thickness measurement machine Fisher MMS eddy current method probe EAW3.3. The amount of decrease in the film thickness of the charge transport layer is evaluated by a value obtained by converting the amount of decrease in the film thickness after outputting 10,000 sheets per 1,000.

<Evaluation of scratch resistance>
The surface of the electrophotographic photosensitive member after the above evaluation at a position 180 mm from the upper end portion of the photosensitive member, using a surface roughness measuring device (Surfcoder SE-3400, manufactured by Konishi Research Institute), has a ten-point average roughness in JIS B 0601: 2001. Evaluation (evaluation length 10 mm) was performed according to the evaluation (Rzjis).

DESCRIPTION OF SYMBOLS 1 electrophotographic photosensitive member 2 axis 3 charging means 4 exposure light 5 developing means 6 transfer means 8 fixing means 9 process cartridge 10 guiding means P transfer material 101 support 102 undercoat layer 103 charge generation layer 104 charge transport layer

Claims (8)

In an electrophotographic photosensitive member having a surface layer containing a charge transport substance and a polyester resin,
The surface layer contains alumina particles having a volume average particle size of 10 nm to 200 nm,
The polyester resin has a structure represented by the general formula (I) and a structure represented by the general formula (II),

(In the general formula (I), X ¹ represents a divalent group.)

(In the general formula (II), X ² represents a single bond, an oxygen atom, an alkylidene group or a cycloalkylidene group. R ^{11 to} R ¹⁸ each independently represent a hydrogen atom or an alkyl group.)
An electrophotographic photosensitive member, wherein the structure represented by the general formula (II) has a structure represented by the general formula (II-1) and a structure represented by the general formula (II-3).

(In General Formula (II-1), R ²¹ represents a hydrogen atom, a methyl group, an ethyl group or a phenyl group. R ²² and R ²³ each independently represent an alkyl group having 1 to 4 carbon atoms. R ²⁴ to R ²⁷ are, .m representing each independently a hydrogen atom or a methyl group, an integer of 0 to 3.)

(In General Formula (II-3), R ^{41 to} R ⁴⁴ each independently represent a hydrogen atom or a methyl group.) In the polyester resin, the proportion of the structure represented by the general formula (II-3) in the structure represented by the general formula (II) is 35 mol% or more and 80 mol% or less, and
2. The electrophotographic photosensitive member according to claim 1, wherein the content of the alumina particles is 1% by mass or more and 10% by mass or less with respect to the content of the polyester resin in the surface layer.   The polyester resin according to claim 1 or 2, wherein the proportion of the structure represented by the general formula (II-1) in the structure represented by the general formula (II) is 35 mol% or more and 65 mol% or less. Electrophotographic photosensitive member. The structure represented by the general formula (I) contains the structure represented by the formula (I-1), and
The polyester resin according to any one of claims 1 to 3, wherein the proportion of the structure represented by the formula (I-1) in the structure represented by the general formula (I) is 65 mol% or more. The electrophotographic photosensitive member according to the above.
  The electrophotographic photosensitive member according to any one of claims 1 to 4, wherein the volume average particle diameter of the alumina particles is 10 nm or more and 100 nm or less. The electrophotographic photosensitive member according to any one of claims 1 to 5, wherein the alumina particles are surface-treated with a compound represented by the general formula (IV-1) or a compound represented by the general formula (IV-2). body.

(In formula (IV-1), R ⁵¹ represents a methyl group, a methoxy group or an alkyl group. R ⁵² and R ⁵³ each independently represent a methyl group or an ethyl group.)

(In formula (IV-2), R ⁶¹ represents a methyl group, a methoxy group or an alkyl group. R ⁶² and R ⁶³ each independently represent a methyl group or an ethyl group.)   An electrophotographic photoreceptor according to any one of claims 1 to 6, and at least one means selected from the group consisting of charging means, developing means, transfer means and cleaning means are integrally supported, and electrophotography A process cartridge characterized by being removable from an apparatus body. An electrophotographic apparatus comprising the electrophotographic photosensitive member according to any one of claims 1 to 6, a charging unit, an exposure unit, a developing unit, and a transfer unit.