JPH0728261A - Electrophotographic photoreceptor - Google Patents

Abstract

PURPOSE:To form a three-dimensional skeleton structure and to improve solvent resistance by caused hardening by polymerizing and crosslinking a 1st compd. having two or more isocyanate groups and a 2nd compd. having two or more hydroxyl or -CH2OH groups. CONSTITUTION:This electrophotographic photoreceptor is provided with an electric charge generating layer 4 and an electric charge transferring layer 3 on the electric conductive substrate 1, the electric charge generating layer 4 generates electrons and positive holes when irradiating with light, and the electric charge transferring layer 3 is formed by polymerizing and crosslinking a 1st compd. having two or more isocyanate groups and a 2nd compd. having two or more hydroxyl or -CH2OH groups. One or more of the 1st and 2nd compds. are triphenylamine type nitrogen compds. and the 1st and 2nd compds. transfer positive holes generated in the electric charge generating layer 4. When the 1st and 2nd compds. are polymerized and crosslinked, a three-dimensional skeleton structure is formed and the solvent resistance of the electric charge transferring layer 3 is improved by caused hardening.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a positive charging type electrophotographic photoreceptor, and more particularly to the structure of a charge transport layer.

[0002]

2. Description of the Related Art Conventionally, as a photosensitive material for an electrophotographic photoreceptor (hereinafter also referred to as a photoreceptor), an inorganic photoconductive substance such as selenium or a selenium alloy, or an organic photoconductive substance such as a phthalocyanine compound or a bisazo compound is used as a resin. Those dispersed in a binder or the like and those vacuum-deposited are used.

The photoconductor is required to have a function of holding a surface charge in a dark place, a function of receiving light to generate a charge, and a function of receiving light to transport a charge, but with one layer. A so-called single-layer type photoreceptor having these functions together,
There is a so-called laminated type photoreceptor in which functionally separated layers are laminated mainly on a layer that contributes to charge generation and a layer that contributes to holding surface charges in a dark place and transporting charges when receiving light. For example, the Carlson method is applied to the image formation by the electrophotographic method using these photoconductors. Image formation by this method is performed by corona discharge to a photoconductor in a dark place, formation of an electrostatic latent image such as characters and pictures of an original on the charged photoconductor surface,
The formed electrostatic latent image is developed with toner, and the developed toner image is fixed on a support such as paper, and the photoconductor after the toner image transfer is neutralized, residual toner is removed, and optical neutralization is performed. And then reused.

In recent years, many applications of photoconductive organic compounds having excellent charge transporting ability to photoconductors have been proposed due to advantages such as flexibility, thermal stability, and film forming property. Negative charging type photoconductors and positive charging type photoconductors are known as photoconductors for organic electrophotography. Negative charging type photoconductors are used for photoconductors of laser beam printers and copiers, and positive charging photoconductors are partially put into practical use as single layer type photoconductors.

[0005]

The positive charging type photoconductor does not generate ozone unlike the negative charging type photoconductor, and since it is a laminated type with high sensitivity, it is a promising electrophotographic photoconductor. Although conceivable, the positively charged laminated electrophotographic photoreceptor has the following problems. Laminated electrophotographic photoreceptors are formed by sequentially stacking a charge transport layer and a charge generation layer. Polycarbonate is used as a binder for the charge transport layer, and triphenylamine, stilbene compounds, diamine compounds, etc. are used as charge transport materials. Since a low molecular weight compound is used, it is easily dissolved in a solvent, and the charge transport layer is deformed or dissolved during application of the charge generation layer, resulting in a poor image on the photoreceptor. When the charge generating substance is an azo compound, an ether solvent such as tetrahydrofuran or diethoxyethane or a ketone solvent such as methyl ethyl ketone or cyclohexanone is used as a solvent for the coating liquid for the charge generating layer. These solvents dissolve well the low-molecular weight charge-transporting substances such as triphenylamine. Furthermore, even if a thermosetting resin such as an epoxy resin is used as the binder of the charge transport layer, it is difficult to prevent the dissolution of the charge transport substance such as triphenylamine.

Thus, the dipping method cannot be applied to the production of organic photoconductors. Other methods for coating the charge generation layer on the charge transport layer include a seal coat method and a spray method. However, the seal coat method is liable to scratch the photoreceptor due to contact with the coating jig, and the spray method is used. However, it has not been put into practical use because it is difficult to form a uniform coating film due to uneven evaporation of the solvent in the spray.

The present invention has been made in view of the above points, and an object thereof is to enhance the solvent resistance of the charge transport layer, thereby making it possible to apply the dip method, and to improve the mass productivity and characteristics. To provide a photoconductor.

[0008]

According to the present invention, there is provided a positive charging type electrophotographic photosensitive member, which comprises (1) a charge generating layer and (2) a charge transporting layer on a conductive substrate. Have
The charge generation layer generates electrons and holes by irradiation with light, and the charge transport layer has a first compound containing two or more isocyanate groups and a second compound containing two or more hydroxyl groups or --CH ₂ OH groups in both groups. This is accomplished by polymerizing and cross-linking the compound of 1) and at least one of the first and second compounds is a triphenylamine nitrogen compound and transports holes generated in the charge generation layer. To be done.

The triphenylamine nitrogen compound containing two or more isocyanate groups is a triphenylamine compound represented by the general formula (I), a hydrazone compound represented by the general formula (II), or a stilbene compound represented by the general formula (III). A compound or a diamine compound represented by the general formula (IV). The triphenylamine-based nitrogen compound containing two or more hydroxyl groups or —CH ₂ OH groups in both groups is a triphenylamine compound represented by the general formula (V), a hydrazone compound represented by the general formula (VI), or a general formula (VII ) Or a diamine compound represented by the general formula (VIII).

A specific example is shown below.

[0011]

[Chemical 13]

[0012]

[Chemical 14]

[0013]

[Chemical 15]

Compounds which can be combined with the compounds represented by the chemical formula (I-1), the chemical formula (II-1), the chemical formula (III-1) and the chemical formula (IV-1) are represented by the chemical formula (V-
1), (VI-1), (VII-1), and (VIII-1), as well as polyester polyol, polyether polyol, polycarbonate polyol, epoxy resin, phenoxy resin, and the like.

Chemical formulas (V-1), (VI-1), (VII-
Compounds which can be combined with the compounds represented by 1) and (VIII-1) include, in addition to the above-mentioned compounds, trimethylene diisocyanate, diphenylmethane diisocyanate, polymethylene polyphenyl polyisocyanate, hexamethylene diisocyanate, tolylene diisocyanate and their modified products, There are compositions and the like.

Furthermore, a diamine compound represented by the general formula (IV) having a high charge mobility and a chemically stable skeleton structure, containing two or more isocyanate groups, has a low molecular weight and a high charge mobility and is chemically stable. General formula (V) having a stable structure
To the triphenylamine represented by a hydroxyl group or --CH ₂ OH
When a compound containing two or more groups in both groups is combined and the equivalent ratio of the total amount of the hydroxyl group and the —CH ₂ OH group to the isocyanate group is from 1: 1 to 1: 1.2, the photoreceptor characteristics are Especially good.

[0017]

[Function] When a first compound containing two or more isocyanate groups and a second compound containing two or more hydroxyl groups or -CH ₂ OH groups in both groups are polymerized and crosslinked, a three-dimensional skeleton structure is formed and cured. Causes solvent resistance to improve. The triphenylamine-based nitrogen compound is a hole-conductive charge transport material.

[0018]

FIG. 1 is a sectional view showing a positive charging type electrophotographic photoconductor according to an embodiment of the present invention. The positive charging type electrophotographic photoreceptor is formed by laminating an undercoat layer 2, a charge transport layer 3, a charge generating layer 4, and an overcoat layer 5 on a conductive substrate 1 in this order. The conductive substrate 1 is, for example, a plate made of aluminum and an aluminum alloy, nickel, stainless steel, or the like, and a tube which is formed into a raw tube by a method such as extrusion or drawing and then surface-treated by cutting, polishing, or gold, palladium, A metal such as chromium or platinum or a metal oxide such as indium oxide or tin oxide coated on a cylindrical or film-shaped plastic by vapor deposition or sputtering can be used.

As the undercoat layer 2, polyamide, polypeptide, ethyl cellulose, casein, quaternary ammonium salt-containing polymer, maleic anhydride polymer, vinyl acetate-ethylene polymer, polyvinylpyrrolidone, polyvinyl alcohol, polyvinyl butyral. , Polyurethane, sodium polyacrylate, methoxymethylated nylon, melamine resin, phenol resin,
Thermoplastic resins such as alkyd resins, epoxy resins, polyester resins, and thermosetting resins are used. The undercoat layer 2 is coated with a powder of titanium oxide, zirconium oxide, tin oxide, indium oxide or the like, a metal powder of aluminum, nickel, etc., or a metal oxide such as tin oxide on the surface thereof in order to reduce the residual potential. Fine particles of silica, alumina, calcium carbonate, glass, plastic, etc., which have been subjected to vapor deposition, plating, etc., may be added. The thickness of the undercoat layer 2 is 50 to 300.
It can be used in the range of 00 nm. As the solvent, alcohol type, ketone type, ether type and the like can be used.

The charge generating material used in the charge generating layer 4 includes phthalocyanine compounds, azo compounds, squarylium compounds, polycyclic quinone pigments, perylene pigments and the like. A specific example is shown below.

[0021]

[Chemical 16]

[0022]

[Chemical 17]

[0023]

[Chemical 18]

[0024]

[Chemical 19]

[0025]

[Chemical 20]

[0026]

[Chemical 21]

[0027]

[Chemical formula 22]

As a binder for the charge generation layer 4, ethyl cellulose, cellulose acetate, maleic anhydride polymer, vinyl acetate-ethylene polymer, vinyl acetate-
Vinylidene chloride copolymer, vinyl chloride-vinyl acetate copolymer containing sulfonium salt, vinyl chloride-vinyl acetate copolymer, polystyrene, polycarbonate, acrylonitrile-styrene copolymer, polyarylate, polyvinyl butyral, polyvinyl formal, polyvinyl acetate, Polyurethane, acrylic resin, phenoxy resin,
Thermoplastic resins and thermosetting resins such as melamine resin, phenol resin, alkyd resin, epoxy resin, polyester resin and ketone resin, and their halides are used.

As the curing agent for the thermosetting resin binder for the charge generating layer used in the present invention, organic diisocyanate is excellent in the characteristics of the photoreceptor, the reaction speed and the dispersibility of the charge generating agent. Examples of the organic diisocyanate include aromatic diisocyanates such as tolylene diisocyanate, xylene-1,4-diisocyanate and 4,4-diphenylmethane diisocyanate, aliphatic diisocyanates such as tetramethylene diisocyanate, alicyclic compounds such as water-added diphenylmethane diisocyanate and cyclohexane diisocyanate. Diisocyanate or the like is used.

As the overcoat layer 5, silicon,
Metal alkoxide compounds such as titanium, indium and zirconium, butyl etherified melamine-formaldehyde resin, acrylic resin, urethane resin and the like can be used alone or in admixture of two or more. If necessary, fine particles of 0.3 μm or less such as silica and alumina can be added.

The solvent for the overcoat layer is not particularly limited when a thermosetting resin is used as the binder of the charge generation layer and the coating is performed after curing the thermosetting resin. When the binder of the charge generation layer is a thermoplastic resin, it is limited because it is easily dissolved in a solvent. For example, when the binder of the charge generation layer is a thermoplastic resin such as vinyl chloride resin, ethanol or the like is selected as the solvent of the overcoat layer.

The thickness of the overcoat layer 5 is 0.
A range of 5 to 5 μm is used, but preferably 0.5 to 2 μm
Those in the range of m are used. The solvent used for the charge transport layer coating solution may be any solvent that completely dissolves the charge transporting substance, such as acetone, cyclohexanone, ketones such as methyl ethyl ketone, ethers such as tetrahydrofuran, dioxane and dimethoxyethane, A chlorine-based solvent such as dichloromethane, chloroform or trichloroethylene can be used.

Stabilizers for the charge transport layer include triethylene glycol-bis [3- (3-t-butyl-5-methyl-4-
Hydroxyphenyl) propionate], 2,4-bis- (n-octylthio) -6- (4-hydroxy-3,5-di-t-butylanilino) -1,3,5-triazine, tris- (3,5 -J
-t-Butyl-4-hydroxybenzyl) -isocyanate and other hindered phenolic stabilizers, tris (2,4-diene)
Phosphorus stabilizers such as -t-butylphenyl) phosphite and hydroquinone stabilizers such as hydroquinone and 2,5-bis (1,1-dimethylbutyl) hydroquinone can be used.

The coating liquid for the charge generating layer is prepared as follows. 100 g of the azo pigment represented by the chemical formula (IX-1) as a charge generating substance, 50 g of polyvinyl acetate as a binder, and methyl ethyl ketone 8 as a solvent.
Knead kg for 4 hours using a sand mill disperser. The overcoat layer coating solution is prepared as follows. As a binder, 2 kg of metal alkoxide (trade name: Atron NSi-310, solid content 5%, manufactured by Nippon Soda),
A solution prepared by dissolving 100 g of modified polyamide (trade name: CM-8000, manufactured by Toray) in 900 g of methanol in advance and 100 g of a polyurethane resin (polyol) (trade name: Nipporan 800, solid content 100%, manufactured by Nippon Polyurethane Industry Co., Ltd.) with a stirrer. After mixing for 1 hour, 20 g of polyisocyanate (trade name: Takenate D165N90CX, manufactured by Takeda Pharmaceutical Co., Ltd.) was added, and the mixture was further stirred with a stirrer for 30 minutes. Example 1 A charge transport layer coating solution is prepared as follows. As a substance containing two or more hydroxyl groups, 609 g of the triphenylamine compound represented by the chemical formula (V-1), and as a substance containing two or more isocyanate groups, 650 g of the triphenylamine compound represented by the chemical formula (I-1) in 3000 g of dichloromethane. To prepare a coating solution. The equivalent ratio of isocyanate groups to hydroxyl groups in this liquid is 1: 1.1. An aluminum drum having an inner diameter of 60 mm, a wall thickness of 1 mm and a length of 350 mm is used, and the film is dried by a dip method at a pulling speed of 2 mm / s. It was applied to a thickness of 20 μm, dried at 60 ° C. for 30 minutes, and further dried at 120 ° C. for 60 minutes and cured to form a charge transport layer.

The drum on which the charge transport layer is formed is dipped in the coating liquid for the charge generation layer, and the pulling rate is set to 2 by the dip method.
The charge generation layer was formed under the conditions of 0 mm / s so as to have a film thickness after drying of 0.5 μm and dried at 80 ° C. for 30 minutes.
The drum having the charge generation layer formed on the charge transport layer is dipped in the coating liquid for the overcoat layer, and coated by the dip method at a pulling speed of 20 mm / s so that the film thickness after drying is 1.0 μm. After that, it was dried at 80 ° C. for 30 minutes to form an overcoat layer. Example 2 The coating liquid for charge transport layer is prepared as follows. As a substance containing two or more hydroxyl groups, 609 g of the triphenylamine compound represented by the chemical formula (V-1), and as a substance containing two or more isocyanate groups, 1042 g of the hydrazone compound represented by the chemical formula (II-1) in dichloromethane 3
It was dissolved in 000 g to prepare a coating solution. The equivalent ratio of isocyanate groups to hydroxyl groups in this liquid is 1: 1.1. An aluminum drum having an inner diameter of 60 mm, a wall thickness of 1 mm and a length of 350 mm is used, and the film is dried by a dip method at a pulling speed of 2 mm / s. It was applied to a thickness of 20 μm, dried at 60 ° C. for 30 minutes, and further dried at 120 ° C. for 60 minutes and cured to form a charge transport layer.

The drum on which the charge transport layer is formed is dipped in the coating liquid for the charge generation layer, and the pulling speed is set to 2 by the dip method.
The charge generation layer was formed under the conditions of 0 mm / s so as to have a film thickness after drying of 0.5 μm and dried at 80 ° C. for 30 minutes.
The drum having the charge generation layer formed on the charge transport layer is dipped in the coating liquid for the overcoat layer, and coated by the dip method at a pulling speed of 20 mm / s so that the film thickness after drying is 1.0 μm. After that, it was dried at 80 ° C. for 30 minutes to form an overcoat layer. Example 3 The coating liquid for charge transport layer is prepared as follows. 609 g of the triphenylamine compound represented by the chemical formula (V-1) as a substance containing two or more hydroxyl groups and 1010 g of the stilbene compound represented by the chemical formula (III-1) as a substance containing two or more isocyanate groups were dissolved in 3000 g of dichloromethane. To prepare a coating solution. The equivalent ratio of isocyanate groups to hydroxyl groups in this liquid is 1: 1.1. An aluminum drum having an inner diameter of 60 mm, a wall thickness of 1 mm and a length of 350 mm is used, and the film is dried by a dip method at a pulling speed of 2 mm / s. It was applied to a thickness of 20 μm, dried at 60 ° C. for 30 minutes, and further dried at 120 ° C. for 60 minutes and cured to form a charge transport layer.

The drum on which the charge transport layer is formed is dipped in the coating liquid for the charge generation layer, and the pulling rate is set to 2 by the dip method.
The charge generation layer was formed under the conditions of 0 mm / s so as to have a film thickness after drying of 0.5 μm and dried at 80 ° C. for 30 minutes.
The drum having the charge generation layer formed on the charge transport layer is dipped in the coating liquid for the overcoat layer, and coated by the dip method at a pulling speed of 20 mm / s so that the film thickness after drying is 1.0 μm. After that, it was dried at 80 ° C. for 30 minutes to form an overcoat layer. Example 4 The coating liquid for charge transport layer is prepared as follows. 609 g of the triphenylamine compound represented by the chemical formula (V-1) as a substance containing two or more hydroxyl groups, and 1130 g of the diamine compound represented by the chemical formula (IV-1) as a substance containing two or more isocyanate groups in dichloromethane 30
A coating solution was prepared by dissolving it in 00 g. The equivalent ratio of isocyanate groups to hydroxyl groups in this liquid is 1: 1.1. An aluminum drum having an inner diameter of 60 mm, a wall thickness of 1 mm and a length of 350 mm is used, and the film is dried by a dip method at a pulling speed of 2 mm / s. It was applied to a thickness of 20 μm, dried at 60 ° C. for 30 minutes, and further dried at 120 ° C. for 60 minutes and cured to form a charge transport layer.

The drum on which the charge transport layer is formed is dipped in the coating liquid for the charge generation layer, and the pulling rate is set to 2 by the dip method.
The charge generation layer was formed under the conditions of 0 mm / s so as to have a film thickness after drying of 0.5 μm and dried at 80 ° C. for 30 minutes.
The drum having the charge generation layer formed on the charge transport layer is dipped in the coating liquid for the overcoat layer, and coated by the dip method at a pulling speed of 20 mm / s so that the film thickness after drying is 1.0 μm. After that, it was dried at 80 ° C. for 30 minutes to form an overcoat layer. Example 5 The coating liquid for charge transport layer is prepared as follows. 609 g of a triphenylamine compound represented by the chemical formula (V-1) as a substance containing two or more hydroxyl groups, and 472 g of a compound represented by the chemical formula (XIV) as a substance containing two or more isocyanate groups are dissolved in 3000 g of dichloromethane and applied. A liquid was created. The equivalent ratio of isocyanate groups to hydroxyl groups in this liquid is 1: 1.1. An aluminum drum having an inner diameter of 60 mm, a wall thickness of 1 mm and a length of 350 mm is used, and the film is dried by a dip method at a pulling speed of 2 mm / s. It was applied to a thickness of 20 μm, dried at 60 ° C. for 30 minutes, and further dried at 120 ° C. for 60 minutes and cured to form a charge transport layer.

The drum on which the charge transport layer is formed is dipped in the coating liquid for the charge generation layer, and the pulling rate is set to 2 by the dip method.
The charge generation layer was formed under the conditions of 0 mm / s so as to have a film thickness after drying of 0.5 μm and dried at 80 ° C. for 30 minutes. The drum having the charge generation layer formed on the charge transport layer is dipped in the coating liquid for the overcoat layer, and coated by the dip method at a pulling speed of 20 mm / s so that the film thickness after drying is 1.0 μm. After that, it was dried at 80 ° C. for 30 minutes to form an overcoat layer. Example 6 The coating liquid for charge transport layer is prepared as follows. 609 g of a triphenylamine compound represented by the chemical formula (V-1) as a substance containing two or more hydroxyl groups, and 556 g of a compound represented by the chemical formula (XV) as a substance containing two or more isocyanate groups are dissolved in 3000 g of dichloromethane and applied. A liquid was created. The equivalent ratio of isocyanate groups to hydroxyl groups in this liquid is 1: 1.1. An aluminum drum having an inner diameter of 60 mm, a wall thickness of 1 mm and a length of 350 mm is used, and the film is dried by a dip method at a pulling speed of 2 mm / s. It was applied to a thickness of 20 μm, dried at 60 ° C. for 30 minutes, and further dried at 120 ° C. for 60 minutes and cured to form a charge transport layer.

The drum on which the charge transport layer is formed is dipped in the coating liquid for the charge generation layer, and the pulling rate is set to 2 by the dip method.
The charge generation layer was formed under the conditions of 0 mm / s so as to have a film thickness after drying of 0.5 μm and dried at 80 ° C. for 30 minutes.
The drum having the charge generation layer formed on the charge transport layer is dipped in the coating liquid for the overcoat layer, and coated by the dip method at a pulling speed of 20 mm / s so that the film thickness after drying is 1.0 μm. After that, it was dried at 80 ° C. for 30 minutes to form an overcoat layer. Example 7 The coating liquid for charge transport layer is prepared as follows. 1032 g of the hydrazone compound represented by the chemical formula (VI-1) as a substance containing two or more hydroxyl groups, and 650 g of the triphenylamine compound represented by the chemical formula (I-1) as a substance containing two or more isocyanate groups in dichloromethane 3
It was dissolved in 000 g to prepare a coating solution. The equivalent ratio of isocyanate groups to hydroxyl groups in this liquid is 1: 1.1. An aluminum drum having an inner diameter of 60 mm, a wall thickness of 1 mm and a length of 350 mm is used, and the film is dried by a dip method at a pulling speed of 2 mm / s. It was applied to a thickness of 20 μm, dried at 60 ° C. for 30 minutes, and further dried at 120 ° C. for 60 minutes and cured to form a charge transport layer.

The drum on which the charge transport layer is formed is dipped in the coating liquid for the charge generation layer, and the pulling rate is set to 2 by the dip method.
The charge generation layer was formed under the conditions of 0 mm / s so as to have a film thickness after drying of 0.5 μm and dried at 80 ° C. for 30 minutes.
The drum having the charge generation layer formed on the charge transport layer is dipped in the coating liquid for the overcoat layer, and coated by the dip method at a pulling speed of 20 mm / s so that the film thickness after drying is 1.0 μm. After that, it was dried at 80 ° C. for 30 minutes to form an overcoat layer. Example 8 A charge transport layer coating liquid is prepared as follows. 1001 g of the stilbene compound represented by the chemical formula (VII-1) as a substance containing two or more hydroxyl groups, and 650 g of the triphenylamine compound represented by the chemical formula (I-1) as a substance containing two or more isocyanate groups are dissolved in 3000 g of dichloromethane. To prepare a coating solution. The equivalent ratio of isocyanate groups to hydroxyl groups in this liquid is 1: 1.1. An aluminum drum having an inner diameter of 60 mm, a wall thickness of 1 mm and a length of 350 mm is used, and the film is dried by a dip method at a pulling speed of 2 mm / s. It was applied to a thickness of 20 μm, dried at 60 ° C. for 30 minutes, and further dried at 120 ° C. for 60 minutes and cured to form a charge transport layer.

The drum on which the charge transport layer is formed is dipped in the coating liquid for the charge generation layer, and the pulling rate is set to 2 by the dip method.
The charge generation layer was formed under the conditions of 0 mm / s so as to have a film thickness after drying of 0.5 μm and dried at 80 ° C. for 30 minutes.
The drum having the charge generation layer formed on the charge transport layer is dipped in the coating liquid for the overcoat layer, and coated by the dip method at a pulling speed of 20 mm / s so that the film thickness after drying is 1.0 μm. After that, it was dried at 80 ° C. for 30 minutes to form an overcoat layer. Example 9 A charge transport layer coating liquid is prepared as follows. 1144 g of the diamine compound represented by the chemical formula (VIII-1) as a substance containing two or more hydroxyl groups, and 650 g of the triphenylamine compound represented by the chemical formula (I-1) as a substance containing two or more isocyanate groups in dichloromethane 3
It was dissolved in 000 g to prepare a coating solution. The equivalent ratio of isocyanate groups to hydroxyl groups in this liquid is 1: 1.1. An aluminum drum having an inner diameter of 60 mm, a wall thickness of 1 mm and a length of 350 mm is used, and the film is dried by a dip method at a pulling speed of 2 mm / s. It was applied to a thickness of 20 μm, dried at 60 ° C. for 30 minutes, and further dried at 120 ° C. for 60 minutes and cured to form a charge transport layer.

The drum on which the charge transport layer is formed is dipped in the coating liquid for the charge generation layer, and the pulling rate is set to 2 by the dip method.
The charge generation layer was formed under the conditions of 0 mm / s so as to have a film thickness after drying of 0.5 μm and dried at 80 ° C. for 30 minutes.
The drum having the charge generation layer formed on the charge transport layer is dipped in the coating liquid for the overcoat layer, and coated by the dip method at a pulling speed of 20 mm / s so that the film thickness after drying is 1.0 μm. After that, it was dried at 80 ° C. for 30 minutes to form an overcoat layer. Example 10 The coating liquid for charge transport layer is prepared as follows. −
671 g of a triphenylamine compound represented by the chemical formula (V-2) as a substance containing two or more CH ₂ OH groups and a chemical formula (IV-1) as a substance containing two or more isocyanate groups
1110 g of the diamine compound shown by was dissolved in 3000 g of dichloromethane to prepare a coating solution. The equivalence ratio of isocyanate groups and -CH ₂ OH groups of this liquid is 1: 1.1. Using an aluminum drum having an inner diameter of 60 mm, a wall thickness of 1 mm and a length of 350 mm, the dipping method is used under the condition of a pulling speed of 2 mm / s. It was applied so that the film thickness after drying was 20 μm, dried at 60 ° C. for 30 minutes, and further dried at 120 ° C. for 60 minutes and cured to form a charge transport layer.

The drum on which the charge transport layer is formed is dipped in the coating liquid for the charge generation layer, and the pulling rate is set to 2 by the dip method.
The charge generation layer was formed under the conditions of 0 mm / s so as to have a film thickness after drying of 0.5 μm and dried at 80 ° C. for 30 minutes.
The drum having the charge generation layer formed on the charge transport layer is dipped in the coating liquid for the overcoat layer, and coated by the dip method at a pulling speed of 20 mm / s so that the film thickness after drying is 1.0 μm. After that, it was dried at 80 ° C. for 30 minutes to form an overcoat layer. Example 11 The coating liquid for charge transport layer is prepared as follows. As a substance containing two or more hydroxyl groups, 500 g of the triphenylamine compound represented by the chemical formula (V-1), and as a substance containing two or more isocyanate groups, 1110 g of the diamine compound represented by the chemical formula (IV-1) in dichloromethane 30
A coating solution was prepared by dissolving it in 00 g. The equivalent ratio of isocyanate groups to hydroxyl groups in this solution is 1: 0.9. An aluminum drum having an inner diameter of 60 mm, a wall thickness of 1 mm and a length of 350 mm is used, and the film is dried by a dip method at a pulling speed of 2 mm / s. It was applied to a thickness of 20 μm, dried at 60 ° C. for 30 minutes, and further dried at 120 ° C. for 60 minutes and cured to form a charge transport layer.

The drum on which the charge transport layer is formed is dipped in the coating liquid for the charge generation layer, and the pulling speed is set to 2 by the dip method.
The charge generation layer was formed under the conditions of 0 mm / s so as to have a film thickness after drying of 0.5 μm and dried at 80 ° C. for 30 minutes.
The drum having the charge generation layer formed on the charge transport layer is dipped in the coating liquid for the overcoat layer, and coated by the dip method at a pulling speed of 20 mm / s so that the film thickness after drying is 1.0 μm. After that, it was dried at 80 ° C. for 30 minutes to form an overcoat layer. Example 12 The coating liquid for charge transport layer is prepared as follows. 665 g of a triphenylamine compound represented by the chemical formula (V-1) as a substance containing two or more hydroxyl groups, and 1130 g of a diamine compound represented by the chemical formula (IV-1) as a substance containing two or more isocyanate groups in dichloromethane 30
A coating solution was prepared by dissolving it in 00 g. The equivalent ratio of isocyanate groups to hydroxyl groups in this liquid is 1: 1.2. An aluminum drum having an inner diameter of 60 mm, a wall thickness of 1 mm and a length of 350 mm is used, and the film is dried by a dip method at a pulling rate of 2 mm / s. It was applied to a thickness of 20 μm, dried at 60 ° C. for 30 minutes, and further dried at 120 ° C. for 60 minutes and cured to form a charge transport layer.

The drum on which the charge transport layer is formed is dipped in the coating liquid for the charge generation layer, and the pulling rate is set to 2 by the dip method.
The charge generation layer was formed under the conditions of 0 mm / s so as to have a film thickness after drying of 0.5 μm and dried at 80 ° C. for 30 minutes.
The drum having the charge generation layer formed on the charge transport layer is dipped in the coating liquid for the overcoat layer, and coated by the dip method at a pulling speed of 20 mm / s so that the film thickness after drying is 1.0 μm. After that, it was dried at 80 ° C. for 30 minutes to form an overcoat layer. Example 13 The coating liquid for charge transport layer is prepared as follows. 720 g of a triphenylamine compound represented by the chemical formula (V-1) as a substance containing two or more hydroxyl groups, and 1130 g of a diamine compound represented by the chemical formula (IV-1) as a substance containing two or more isocyanate groups in dichloromethane 30
A coating solution was prepared by dissolving it in 00 g. The equivalent ratio of isocyanate groups to hydroxyl groups in this solution is 1: 1.3. An aluminum drum having an inner diameter of 60 mm, a wall thickness of 1 mm and a length of 350 mm is used, and the film is dried by a dip method at a pulling speed of 2 mm / s. It was applied to a thickness of 20 μm, dried at 60 ° C. for 30 minutes, and further dried at 120 ° C. for 60 minutes and cured to form a charge transport layer.

The drum on which the charge transport layer is formed is dipped in the coating liquid for the charge generation layer, and the pulling rate is set to 2 by the dip method.
The charge generation layer was formed under the conditions of 0 mm / s so as to have a film thickness after drying of 0.5 μm and dried at 80 ° C. for 30 minutes.
The drum having the charge generation layer formed on the charge transport layer is dipped in the coating liquid for the overcoat layer, and coated by the dip method at a pulling speed of 20 mm / s so that the film thickness after drying is 1.0 μm. After that, it was dried at 80 ° C. for 30 minutes to form an overcoat layer. Comparative Example 1 500 g of methylated tolphenylamine and 500 g of polycarbonate (average molecular weight 20,000) as a binder
Is dissolved in 3500 g of dichloromethane to prepare a coating solution for the charge transport layer, which has an inner diameter of 60 mm, a wall thickness of 1 mm and a length of 350 mm.
An aluminum drum having a thickness of 20 mm was coated by a dip method at a pulling rate of 2 mm / s so that the film thickness after drying was 20 μm, and dried at 80 ° C. for 1 hour to form a charge transport layer.

The drum on which the charge transport layer is formed is dipped in the coating liquid for the charge generation layer, and the pulling rate is set to 2 by the dip method.
The charge generation layer was formed under the conditions of 0 mm / s so as to have a film thickness after drying of 0.5 μm and dried at 80 ° C. for 30 minutes.
The drum having the charge generation layer formed on the charge transport layer is dipped in the coating liquid for the overcoat layer, and coated by the dip method at a pulling speed of 20 mm / s so that the film thickness after drying is 1.0 μm. After that, it was dried at 80 ° C. for 30 minutes to form an overcoat layer.

The positively charged layered electrophotographic photoconductor thus prepared was evaluated by a device equivalent to the Carlson method positively charged plain paper copying machine. Drum speed is 50r
pm, the exposure dose is 5 lx.s, and the ambient temperature and humidity (22 ° C, 6
Bright part potential (V), dark part potential (V) under the condition of 0 RH%
And the images were evaluated. The results are shown in Tables 1 and 2.
The equivalent ratio represents (hydroxyl group + -CH ₂ OH group) / isocyanate group.

[0050]

[Table 1]

[0051]

[Table 2]

In the above table, the dark area potential of the drum of the comparative example,
The light area potential is the data at the top of the drum. The image on the drum of the comparative example is poor because the charge transport layer is non-uniformly dissolved during the coating of the charge generation layer except for 3 to 4 cm at the top of the drum.

[0053]

According to the present invention, there is provided a positively charged type electrophotographic photoreceptor having (1) a charge generation layer and (2) a charge transport layer on a conductive substrate, and the charge generation layer is Electrons and holes are generated by irradiation of light, and the charge transport layer has a first compound containing two or more isocyanate groups and a hydroxyl group or --CH ₂ OH.
A group formed by polymerizing and cross-linking a second compound containing two or more groups in both groups. One or more of the first and second compounds are triphenylamine nitrogen compounds, and holes generated in the charge generation layer. Therefore, the first compound containing two or more isocyanate groups, and a hydroxyl group or --CH.
_When the second compound containing two or more ₂ OH groups in both groups is polymerized and crosslinked, a three-dimensional skeleton structure is formed to cause curing and the solvent resistance of the charge transport layer is improved. As a result, the charge generation layer can be laminated by the dipping method, and a positively charged laminated electrophotographic photoreceptor having excellent characteristics can be obtained.

[Brief description of drawings]

FIG. 1 is a sectional view showing an electrophotographic photoreceptor according to an embodiment of the present invention.

[Explanation of symbols]

 1 Conductive Substrate 2 Undercoat 3 Charge Transport Layer 4 Charge Generation Layer 5 Overcoat Layer

Claims (6)

[Claims] 1. A positive charging type electrophotographic photoreceptor, comprising (1) a charge generation layer and (2) a charge transport layer on a conductive substrate, wherein the charge generation layer is irradiated with light to produce electrons. The charge transport layer is formed by polymerizing and cross-linking the first compound containing two or more isocyanate groups and the second compound containing two or more hydroxyl groups or -CH ₂ OH groups in both groups. At least one of the first and second compounds is a triphenylamine-based nitrogen compound, and transports holes generated in the charge generation layer. 2. The photoreceptor according to claim 1, wherein the triphenylamine nitrogen compound containing two or more isocyanate groups is a triphenylamine compound represented by the general formula (I) or a hydrazone represented by the general formula (II). A compound, a stilbene compound represented by the general formula (III) or a general formula (I
An electrophotographic photoreceptor, which is a diamine compound represented by V). [Chemical 1] In general formula (I), A is structural formula (Ia) or (I
It is shown in b). [Chemical 2] (R ₁ , R ₂ , R ₃ , R ₄ , and R ₅ are each an isocyanate group, a hydrogen atom, a halogen atom or an optionally substituted alkyl group, and when A is the structural formula (1a), R ₁ , At least two of R ₂ and R ₃ are isocyanate groups, and R ₁ when A has the structural formula (1b),
At least two of R ₂ , R ₄ and R ₅ are isocyanate groups. ) [Chemical 3] (R ₆ , R ₇ , R ₈ and R ₉ are each an isocyanate group, a hydrogen atom, a halogen atom or an optionally substituted alkyl group, at least two of which are isocyanate groups; and B is substituted. Is an alkyl group, an allyl group, an aryl group, or an aralkyl group.) (R ₁₀ , R ₁₁ , R ₁₂ and R ₁₃ are each an isocyanate group, a hydrogen atom, a halogen atom or an optionally substituted alkyl group, at least two of which are isocyanate groups. Is a good alkyl group, allyl group, aryl group, or aralkyl group.) In general formula (IV), D is structural formula (IVa) or (IV
It is shown in b). [Chemical 6] (R ₁₄ , R ₁₅ , R ₁₆ , R ₁₇ , R ₁₈ , R ₁₉ , and R ₂₀ are an isocyanate group, a hydrogen atom, a halogen atom or an optionally substituted alkyl group, and D is a structural formula (IVa). In the case, at least two of R ₁₄ , R ₁₅ , R ₁₆ , R ₁₇ , and R ₁₈ are isocyanate groups, and when D is structural formula (IVb), R ₁₄ , R ₁₅ , R ₁₆ , R ₁₇ , and R ₁₉ , At least two of R ₂₀ are isocyanate groups.) 3. The triphenylamine-based nitrogen compound containing two or more hydroxyl groups or —CH ₂ OH groups in both groups in the photoreceptor according to claim 1, is a triphenylamine compound represented by the general formula (V), An electrophotographic photoreceptor, which is a hydrazone compound represented by the formula (VI), a stilbene compound represented by the general formula (VII) or a diamine compound represented by the general formula (VIII). [Chemical 7] In the general formula (V), E is a structural formula (Va) or (V
It is shown in b). [Chemical 8] (R ₂₁ , R ₂₂ , R ₂₃ , R ₂₄ , and R ₂₅ are a hydroxyl group, —CH ₂ OH
A group, a hydrogen atom, a halogen atom or an optionally substituted alkyl group, and when E is the structural formula (Va), R ₂₁ , R ₂₂ ,
At least two of R ₂₃ are a hydroxyl group or a —CH ₂ OH group, and when E is the structural formula (Vb), R ₂₁ , R ₂₂ , R ₂₄ ,
At least two of R ₂₅ are a hydroxyl group or a —CH ₂ OH group. ) [Chemical 9] _{(R 26, R 27, R} 28, R 29 are each hydroxyl, -CH ₂ OH
A group, a hydrogen atom, a halogen atom or an optionally substituted alkyl group, at least two of which are a hydroxyl group or a —CH ₂ OH group. F is an optionally substituted alkyl group, allyl group, aryl group or aralkyl group. ) [Chemical 10] (R ₃₀ , R ₃₁ , R ₃₂ , and R ₃₃ are a hydroxyl group, —CH ₂ OH, respectively.
A group, a hydrogen atom, a halogen atom or an optionally substituted alkyl group, at least two of which are a hydroxyl group or a —CH ₂ OH group. G is an optionally substituted alkyl group, allyl group, aryl group, or aralkyl group. ) [Chemical 11] In the general formula (VIII), J is represented by the structural formula (VIIIa) or (VIIIb). [Chemical 12] (R ₃₄ , R ₃₅ , R ₃₆ , R ₃₇ , R ₃₈ , R ₃₉ and R ₄₀ are a hydroxyl group, a —CH ₂ OH group, a hydrogen atom, a halogen atom or an optionally substituted alkyl group, and J is a structural formula. (VIIIa), at least two of R ₃₄ , R ₃₅ , R ₃₆ , R ₃₇ , and R ₃₈ are a hydroxyl group or a —CH ₂ OH group, and when J is structural formula (VIIIb), R ₃₄ , R ₃₅ , R ₃₆ , R ₃₇ ,
At least two of R ₃₉ and R ₄₀ are a hydroxyl group or —CH ₂ O
It is an H group. ) 4. The photoconductor for electrophotography according to claim 1, wherein the polymerization crosslinking is thermal polymerization crosslinking. 5. The photosensitive member according to claim 1, wherein the first compound containing two or more isocyanate groups is represented by the general formula (IV):
Is a diamine compound represented by a hydroxyl group or --CH ₂ O
The second compound containing two or more H groups in each group is represented by the general formula (V)
A photoconductor for electrophotography, which is a triphenylamine compound represented by: 6. The photosensitive member according to claim 5, wherein the equivalent ratio of the number of isocyanate groups contained in the first compound to the number of hydroxyl groups and —CH ₂ OH groups contained in the second compound is 1 to 1 to 1. An electrophotographic photoreceptor characterized by having a ratio of 1.2.