JPH02236555A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To form a coated film so as to have excellent surface hardness and surface lubricity by using polycarbonate resins the constituting components of which consist of specific repeating units as a binder resin of a photosensitive layer. CONSTITUTION:The photosensitive layer is provided on a conductive base. This photosensitive layer contains one or more kinds of the polycarbonate resins, the constituting components of which consist of the repeating units expressed by formula I, as the binder resin. In the formula, R1 to R4 denote a hydrogen atom, 1 to 3C alkyl group or halogen atom; R5 and R6 denote a a hydrogen atom, 1 to 4C alkyl group or aryl group. The electrophotographic sensitive body which has the photosensitive layer having the high surface hardness and surface lubricity in combination is obtd. in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an electrophotographic photoreceptor, and more particularly to an electrophotographic photoreceptor using a silicon-containing polycarbonate resin as a binder resin.

2. Description of the Related Art In recent years, electrophotographic technology has been widely used in fields such as copying machines and laser beam printers because it has the advantage of being able to print at high speed and with high print quality.

As electrophotographic photoreceptors used in these electrophotographic techniques, those using inorganic photoconductive materials such as selenium, selenium-tellurium alloy, selenium-arsenic alloy, and cadmium sulfide are widely known. On the other hand, research on electrophotographic photoreceptors using organic photoconductive materials, which have advantages over electrophotographic photoreceptors using inorganic photoconductive materials in terms of cost and ease of manufacture and disposal, has become active. ing. Among these, functionally separated organic laminated photoreceptors, in which a charge generation layer that generates charges upon exposure and a charge transport layer that transports charges, are stacked are superior in terms of electrophotographic properties such as sensitivity, chargeability, and repeated stability. It is excellent, and various proposals have been made and it has not yet been put into practical use.

Among these organic layered photoreceptors, some have been developed that exhibit sufficient electrophotographic properties as described above.
Durability against external mechanical forces, i.e., problems in which image defects occur due to abrasion or scratches on the surface of the photoreceptor due to direct loads from toner, developer, paper, cleaning members, etc.;
In addition, there are image defects caused by low-resistance substances such as ozone and nitrogen oxides generated by corona discharge, paper dust generated by copy paper, and toner components that adhere and accumulate on the surface of the photoconductor, which can shorten the life of the photoconductor. It is restricted.

Various measures have been considered to solve these problems. For example, methods using polymethyl methacrylate, polyester, polycarbonate resin, etc. as a binder resin for the surface layer of the photoreceptor (Japanese Patent Application Laid-Open No. 57-4051 Publications, etc.) or those containing a lubricant in the binder resin of the photoreceptor surface layer (Japanese Patent Application Laid-open Nos. 63-2072 and 63-5665)
Publication No. 8》 etc. have been proposed.

Problems to be Solved by the Invention However, although these conventionally proposed cases provide electrophotographic photoreceptors with relatively good durability, they are still not fully satisfactory. That is, in the former case,
The pencil hardness of the formed paint film remains in the range of Ha to H, and therefore the surface hardness of the electrophotographic photoreceptor on which it is formed is not fully satisfactory, and is in the range of 40,000 to 50,000.
There remains the problem that image quality defects occur due to abrasion and scratches on the surface of the photosensitive layer after copying approximately 40,000 to 50,000 sheets. There remained the problem that image blurring occurred due to the accumulation of deposits on the surface. Therefore, it has been desired to develop a binder resin that will prevent the formation of a photosensitive layer having high surface hardness.

The present invention has been made in view of the above-mentioned circumstances, and aims to solve the above-mentioned problems in the conventional technology.

That is, an object of the present invention is to provide an electrophotographic photoreceptor having a photosensitive layer having both high surface hardness and surface lubricity.

Means for Solving the Problems As a result of various studies on the binder resin of the photosensitive layer, the inventors found that a polycarbonate resin containing repeating units represented by the following general formula (I>) has an extremely excellent surface. It has both hardness and surface lubricity, and by using it, it simultaneously eliminates the above-mentioned problems, namely, image quality defects due to abrasion and scratches on the surface of the photosensitive layer, and image blurring due to adhesion and accumulation of paper dust, etc. The inventors have discovered that the lifespan of electrophotographic photoreceptors can be dramatically improved, and have completed the present invention.

The present invention provides an electrophotographic photoreceptor comprising a photosensitive layer provided on a conductive substrate, in which the photosensitive layer contains a polycarbonate resin containing repeating units represented by the following general formula (I>) as a binder resin. It is characterized by containing one or more types.

(In the formula, Rヱ, R2, R3 and R4 each represent a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or a halogen atom, and R5 and R6 each represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, and a halogen atom, respectively. represents an alkyl group or an aryl group.) The present invention will be described in detail below.

The conductive substrate in the electrophotographic photoreceptor of the present invention includes:
Conductive materials such as aluminum, nickel, chromium, titanium, palladium, indium oxide, tin oxide, graphite, etc. are placed on metal plates such as aluminum, brass, copper, nickel, and steel, or on metal sheets or plastic sheets. vaporize the substance,
It is possible to use materials that have been coated with sputtering, coating, etc. to make them conductive, or materials that have been made of glass, plastic plates, cloth, paper, etc. that have been made conductive.

A photosensitive layer of a dispersed type, a laminated type, etc. is provided on the conductive substrate, and an undercoat layer having a barrier function or an adhesive function may be provided between the photosensitive layer and the conductive substrate as necessary. It's okay. Materials constituting the undercoat layer include polyvinyl butyral, polyvinyl alcohol, casein,
Resins such as polyamide, cellulose, gelatin, polyurethane, and polyester, and metal oxides such as aluminum oxide can be used.

The photosensitive layer formed on the conductive base plate may have a single layer structure, or may have a laminated structure in which a charge generation layer and a charge transport layer are separated in function. In the case of a laminated structure, the charge generation layer and the charge transport layer may be stacked in any order.

These photosensitive layers are composed of a coating film in which a charge generating substance, a charge transporting substance, or both are contained in a binder resin.

As charge generating substances, amorphous selenium, crystalline selenium,
Selenium-tellurium alloy, selenium-arsenic alloy, other selenium compounds and alloys, inorganic photoconductors such as zinc oxide and titanium oxide, phthalocyanine-based, squarium-based, anthrone-based, berylene-based, azo-based, anthracene-based,
Organic pigments and dyes such as pyrene, biryllium salts, and thiavirylium salts are used.

As the charge transport substance, quinone compounds such as p-penzoquinone, chloranil, promoanil, anthraquinone,
Tetracyanoquinodimethane compounds, 7fluorenone compounds such as 2,4.7-trinitrofluorenone, 2,4,5.7-tetranitrofluorenone, fluorenone-9
- Electron-withdrawing substances such as malononitrile compounds, xanthone compounds, benzophenone compounds, cyanovinyl compounds, ethylene compounds, pyrazoline compounds, hydrazone compounds, oxazole compounds, carbazole compounds, arylalkane compounds, triphenyl An electron-donating substance such as an amine compound, an aryl-substituted ethylene compound, a benzidine compound, a stilbene compound, an anthracene compound, or a polymer having a group consisting of these compounds in its main chain or side chain is used.

Among these, it is particularly preferable to use a triphenylamine compound represented by the following general formula (If).

(In the formula, R7 and R8 each represent H or CH3, and R9 represents H, CH3, C2H5 or Lj.CI) In the present invention, the above polycarbonate resin is used as the binder resin. When the photosensitive layer has a laminated structure in which a charge generation layer and a charge transport layer are functionally separated, the polycarbonate resin can be used as a binder resin for either the charge generation layer or the charge transport layer. It is desirable to use it at least in a layer forming the surface.

In particular, it is preferably used as a binder resin when the surface is comprised of a charge transport layer.

The polycarbonate resin composed of repeating units represented by the above general formula (1) used in the present invention has an average molecular I in the range of 10,000 to 300,000, preferably 20,000 to 200,000.

Specific examples of the above-mentioned polycarbonate resins that can be suitably used in the present invention include those containing the following repeating units as constituent components.

The polycarbonate resin in the present invention can be easily synthesized according to a conventional method using a phenolic compound represented by the following general formula (In).

(In the formula, R1 to R6 have the same meanings as described above.) Specifically, phosgene is introduced into the phenolic compound using pyridine or an aqueous alkali solution as an acid binder in the presence of a methylene chloride solvent. It can be produced by carrying out a reaction. When using an alkaline aqueous solution such as sodium hydroxide as an acid binder,
The phenolic compound, sodium hydroxide, water, methylene chloride, etc. were mixed in appropriate amounts, and phosgene was introduced.
Polymerization can be carried out by adding a tertiary amine compound such as trimethylamine or triethylamine as a catalyst, as well as sodium hydroxide and water, with the proviso that as a molecular regulator,
A method can be adopted in which a monofunctional compound such as phenol or p-tertiary butylphenol is added before, during, or after phosgenation. Next, a typical manufacturing example will be shown.

Synthesis Example 1 Phenolic compound represented by the following structural formula (III-1>) 0.2 mol Sodium hydroxide 18 g Water
250 mJ2 methylene chloride 150 m. l! Leaf tertiary butylphenol Substances of 0.49 or higher,
2 g of phosgene was charged into a reaction vessel, 40 g of phosgene was blown into it for 2 hours while stirring, and 0.0 g of triethylamine was added.
Add 05 g, sodium hydroxide 59, and water 30 mN,
Polymerization was carried out at 25°C for 4 hours. After the polymerization was completed, 400 d of methylene chloride was added to dilute, and the mixture was washed with hydrochloric acid.
After washing with water, evaporate the methylene chloride and
A polycarbonate resin of about 559 (average molecular weight about 30,000) consisting of repeating units shown in 1) was obtained.

CH3 Synthesis Example 2 Phenolic compound represented by the following structural formula (I [I-2>) 0.2 mol Sodium hydroxide 183 Water
250 mfJ methylene chloride 150 m. llp 1st 3rd
0.4 g or more of class butylphenol was charged into a reaction vessel of 29, and a polymerization reaction was carried out in the same manner as in Synthesis Example 1 to obtain about 50 g of a polycarbonate resin consisting of repeating units represented by the following structural formula (I-2). (average molecular weight of about 30,000) was obtained.

Synthesis Example 3 Phenolic compound represented by the following structural formula (III-3) 0.2 mol Sodium hydroxide 18 g Water
250 mN methylene chloride 150 m. l) Leaf tertiary butylphenol 0.4 g or more of the substance, 2! J was charged into a reaction vessel, and a polymerization reaction was carried out in the same manner as in Synthesis Example 1 to obtain about 60 g of polycarbonate resin (average molecular weight: about 30,000) consisting of repeating units represented by the following structural formula (I-3>). Synthesis Example 4 Phenolic compound represented by the following structural formula (I [I-4>) 0.2 mol Sodium hydroxide 18 g Water
250 mN methylene chloride 150 1F1.1lp-tertiary butylphenol 0.43 or more substances were charged into a 2M reaction vessel, and a polymerization reaction was carried out in the same manner as in Synthesis Example 1 to obtain the following structural formula (I-4). Approximately 63 g of polycarbonate resin (average molecule maximum: approximately 30,000) consisting of the repeating unit represented by was obtained.

In the present invention, when the photosensitive layer has a laminated structure, the charge generation layer is formed by applying a coating solution obtained by dispersing or dissolving the above charge generation substance and binder resin in a suitable solvent, and drying. be able to. As a binder resin,
In addition to the above polycarbonate resins, known binder resins such as polystyrene, polyvinyl chloride, polyvinyl acetate, vinyl chloride-vinyl acetate copolymer, polyvinyl acetal, alkyd resin, acrylic resin, polyacrylonitrile, polycarbonate, polyamide, Conventionally known resins can be used, such as thermoplastic resins such as polyketone, polyacrylamide, butyral resin, and polyester, and thermosetting resins such as polyurethane, epoxy resins, and phenol resins.

The thickness of the charge generation layer is usually O. OS~40Ni, preferably O.S. The OS is set to 25p.

Further, the charge transport layer can be formed by applying a solution in which the above-mentioned charge transport substance and the above-mentioned copolymerized polycarbonate resin are dissolved in a suitable solvent and drying the solution. Many useful organic solvents can be used as the solvent used to form the charge transport layer. Typical examples include aromatic hydrocarbons such as benzene, toluene, xylene, and chlorobenzene, ketones such as acetone and 2-butanone, and halogenated aliphatic carbons such as methylene chloride, chloroform, and ethylene chloride. Examples include hydrogens, cyclic or linear ethers such as tetrahydrofuran, dioxane, ethylene glycol, and diethyl ether, and mixed solvents thereof.

The thickness of the charge transport layer is set to 2 to 100/ffi, preferably 10 to ao4.

Example Hereinafter, the present invention will be specifically explained with reference to Examples.

Example 1 An aluminum pipe was used as a conductive substrate, and a coating solution consisting of 10 parts by weight of alcohol-soluble polyamide resin, 150 parts by weight of methanol, and 40 parts by weight of water was applied onto it by dip coating, and dried to form a film with a thickness of 1 ut. A subbing layer was formed. Furthermore, trigonal selenium (manufactured by Xerox Co., Ltd., USA) 90 parts by weight, modified polyvinyl butyral resin 10 parts by weight, n-
Dispersing a mixture consisting of 300 parts by weight of butanol, adding 2 parts by weight of n-butanol to 1 part by weight of the resulting dispersion, and diluting the solution is applied onto the undercoat layer by dip coating, It was dried to form a charge generation layer having a thickness of 0.3IIM.

Next, N,N'-diphenyl-N,N'-bis(3-methylphenyl)-[1.1'-biphenyl]-4.4
3 parts by weight of '-diamine and 10 parts by weight of the polycarbonate resin consisting of repeating units represented by the structural formula (I-1) obtained in Synthesis Example 1 were added to a solvent containing 40 parts by weight of methylene chloride. The resulting solution was dip-coated onto the above charge generation layer and dried to form a charge transport layer with a thickness of 20 mm, thereby producing a three-layer electrophotographic photoreceptor.

The electrophotographic photoreceptor produced as described above was installed in a copying machine equipped with a blade cleaning member, and the cost was 100,000 yen.
We investigated the occurrence of image defects due to abrasion and scratches on the surface of the electrophotographic photoreceptor, the amount of surface abrasion, and the occurrence of image deletion under high temperature and high humidity environments when copying 0 copies. The surface pencil hardness was investigated. The results are shown in Table 1.

Example 2 The same procedure as in Example 1 was used except that the polycarbonate resin consisting of the repeating unit represented by the structural formula (E-2) obtained in Synthesis Example 2 was used as the binder resin of the charge transport layer. An electrophotographic photoreceptor was prepared in the same manner and evaluated in the same manner.The results are shown in Table 1.

Example 3 Everything was the same as in Example 1 above, except that the polycarbonate resin consisting of the repeating unit represented by the structural formula (I-3> obtained in Synthesis Example 2) was used as the binder resin of the charge transport layer. An electrophotographic photoreceptor was prepared by processing the same and evaluated in the same manner.The results are shown in Table 1.

Example 4 The same procedure as in Example 1 was used except that the polycarbonate resin consisting of the repeating unit represented by the structural formula (I-4> obtained in Synthesis Example 2) was used as the binder resin of the charge transport layer. An electrophotographic photoreceptor was prepared in the same manner and evaluated in the same manner.The results are shown in Table 1.

Comparative Example A commercially available polycarbonate resin (manufactured by Teijin ■, Panlite κ-1300) was used as the binder resin for the charge transport layer.
An electrophotographic photoreceptor was prepared in the same manner as in Example 1, except that parts by weight were used, and evaluation was performed in the same manner. The results are shown in Table 1.

Table 1 Effects of the Invention In the present invention, a polycarbonate resin whose constituent component is the repeating unit represented by the above general formula (1) was used as the binder resin of the photosensitive layer, so the formed coating film was extremely excellent. The electrophotographic photoreceptor of the present invention has surface hardness and surface lubricity. Therefore, the electrophotographic photoreceptor of the present invention has excellent durability, suppresses the occurrence of image defects due to abrasion and scratches on the surface of the photosensitive layer, and at the same time, is free from paper dust and other particles. The occurrence of image deletion due to adhesion accumulation is eliminated, and the service life is dramatically improved.

Claims (1)

[Claims] (1) An electrophotographic photoreceptor comprising a photosensitive layer provided on a conductive substrate, in which the photosensitive layer contains, as a binder resin, a polycarbonate resin whose constituent components are repeating units represented by the following general formula (I). An electrophotographic photoreceptor characterized by containing one or more species. ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (I) (In the formula, R_1, R_2, R_3 and R_4 each represent a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or a halogen atom, and R_5 and R_6 are , each represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an aryl group.)