JPH02254461A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To enhance the surface hardness of a photosensitive layer and to prevent occurrence of image quality defects due to its abrasion and scratching by using a specified polycarbonate as a binder resin. CONSTITUTION:The photosensitive layer of a photosensitive body contains the polycarbonate comprising repeating units of formula I and repeating units of formula II, III, or IV, and in formulae I - IV, X is H or alkyl and R is alkyl, and it is preferred to comprise the units of formula I and the units of formula II - IV in a ratio of 10:90 - 90:10, and it is possible form the photosensitive layer of a laminate structure composed of an electric charge generating layer and a charge transfer layer and that of a single layer structure, and to insert an undercoat layer between a conductive substrate and the photosensitive layer.

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 specific polycarbonate resin as a binder resin.

BACKGROUND OF THE INVENTION In recent years, electrophotographic technology has been widely applied in the fields of copying machines, laser beam printers, etc. because it has the advantage of being able to achieve high speed and 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 advanced electroconductive materials is also active, as these electrophotographic photoreceptors have superior advantages in terms of cost, manufacturability, and disposal compared to electrophotographic photoreceptors using inorganic photoconductive materials. I've been doing it. 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 put into practical use.

Some of these organic layered photoreceptors have been developed that exhibit sufficient electrophotographic properties as described above.
Durability against external mechanical forces, that is, image quality defects may occur due to abrasion or scratches on the surface of the photoreceptor due to direct loads from toner, developer, paper, cleaning members, etc., and due to foreign matter adhesion such as toner filming. problems and limit photoreceptor life.

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 have been proposed (Japanese Patent Application Laid-Open No. 1982-
No. 4051 and JP-A-60-172044).

Problems to be Solved by the Invention By the way, when conventionally proposed resins are used as binder resins, electrophotographic photoreceptors with relatively good durability can be obtained, but they are still not fully satisfactory. In other words, the paint film formed using these resins has a pencil hardness of HB.
Therefore, the surface hardness of the formed electrophotographic photoreceptor is not fully satisfactory, and image quality defects due to abrasion and scratches on the surface of the photosensitive layer occur after copying operations of about 40,000 to 50,000 sheets. There were still problems that would arise. Therefore, it has been desired to develop a binder resin that allows 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 with high surface hardness.

Means for Solving the Problems As a result of various studies on the binder resin of the photosensitive layer, the present inventors found that a repeating unit represented by the following structural formula (I),
A polycarbonate resin consisting of a repeating unit represented by the following structural formula (If), (III) or (rV) has extremely excellent surface hardness, and by using it, the above problems can be solved, namely, the photosensitive layer. The present inventors have discovered that the occurrence of image quality defects due to surface wear and scratches can be eliminated, and the lifespan of electrophotographic photoreceptors can be dramatically extended, leading to the completion of 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 repeating unit represented by the following structural formula (I) as a binder resin, and a repeating unit represented by the following structural formula (n).
, (I [I) or (IV)] (hereinafter referred to as "copolymerized polycarbonate resin") (wherein, X is a hydrogen atom or an alkyl (R represents an alkyl group) Hereinafter, the present invention will be explained in detail.

The conductive substrate in the electrophotographic photoreceptor of the present invention includes:
Vapor deposition of conductive substances such as aluminum, nickel, chromium, titanium, palladium, indium oxide, tin oxide, graphite, etc. on metal plates such as aluminum, brass, copper, nickel, and steel, metal sheets, and plastic sheets.
It is possible to use materials that have been subjected to conductive treatment by coating by sputtering, coating, etc., or materials that have been subjected to conductive treatment such as glass, plastic plates, cloth, and paper.

An undercoat layer having a barrier function or an adhesive function may be provided on the conductive substrate, if necessary. Materials constituting the undercoat layer include resins such as polyvinyl butyral, polyvinyl alcohol, casein, polyamide, cellulose, gelatin, polyurethane, and polyester;
Metal oxides such as aluminum oxide can be used.

The photosensitive layer formed on the conductive substrate may have a single layer structure or may have a laminated structure in which a charge generation layer and a charge transport layer are functionally separated. 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 containing a charge generating substance, a charge transporting substance, or both 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, squalium-based, anthrone-based, perylene-based, azo-based, anthraquinone-based, Organic pigments and dyes such as pyrene, pyrylium salts, and thiapyrylium salts are used.

As the charge transport substance, quinone compounds such as p-benzoquinone, chloranil, bromoanil, anthraquinone,
Tetracyanoquinodimethane compounds, fluorenone compounds such as 2.4.7-dolinitrofluorenone and 2.4,5.7-titranitrofluorenone, xanthone compounds, benzophenone compounds, cyanovinyl compounds,
An electron-withdrawing substance such as an ethylene compound, an arylalkane compound, a triphenylamine compound, an aryl-substituted ethylene compound, a benzidine compound, a stilbene compound, an anthracene compound, or a group consisting of such compounds as the main chain. Alternatively, an electron-donating substance such as a polymer having a side chain is used.

In the present invention, the above copolymerized 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 copolymerized polycarbonate resin can be used as a binder resin for either the charge generation layer or the charge transport layer. However, it is necessary to use it at least in the 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 copolymerized polycarbonate resin used in the present invention has a content ratio of repeating units represented by the structural formula (I) to repeating units represented by the structural formula (n), (III), or (IV). It is preferable that the ratio is 10:90 to 90:10.

Further, the viscosity average molecular weight thereof is 10,000 to 200,000, preferably 20,000 to 100,000.

Specific examples of copolycarbonate resins that can be suitably used in the present invention include the following.

The above copolymerized polycarbonate resin is made of 8.3-bis(4
-hydroxyphenyl)-1(311)-isobenzofuranone compound and structural formula (n), (III) or (IV
) can be produced by mixing bisphenol compounds corresponding to the repeating units in a predetermined ratio and reacting with phosgene. Next, a typical example is shown.

Synthesis Example 1 In a 2g reactor, 0.12 mol of 3.3-bis(4-hydroxyphenyl)-1(3+1)-isobenzofuranone and 0.08 mol of 4.4'-(1-methylethylidene)bisphenol , 400 ml of a 4.7% strength aqueous sodium hydroxide solution, and 350 ml of methylene chloride were added, and while stirring vigorously, phosgene was bubbled in at a rate of 400 ml/min for 15 minutes. Keep the reaction temperature at 15℃,
Furthermore, 40 ml of 13.7% sodium hydroxide. )
Limethylbenzylammonium chloride 0.2 gs
and 0.3 ml of triethylamine, and the solution was heated at 23°C.
Stirring was continued for a period of time to carry out the polycondensation reaction. After the reaction is complete, dilute the product with 400 ml of methylene chloride and add 1 g of water.
, 0.5 N of normal hydrochloric acid, and 1 g of water. The obtained organic layer was poured into 5 g of methanol to precipitate a white polymer, and after filtration, the mixture was heated at 100°C for 12
After drying for hours, 70 g of copolymerized polycarbonate resin was obtained.

Synthesis Example 2 4,4'-(1-methylethylidene) in Synthesis Example 1
A polycondensation reaction was carried out in the same manner as in Synthesis Example 1, except that 0.08 mol of 4.4'-(1-phenylethylidene)bisphenol was used instead of bisphenol, to obtain 70 g of copolymerized polycarbonate resin. .

Synthesis Example 3 4,4'-(1-methylethylidene) in Synthesis Example 1
Instead of bisphenol, 4.4'-(L-phenylethylidene)bis(2-methylphenol) 0.08
A polycondensation reaction was carried out in the same manner as in Synthesis Example 1 except that moles were used to obtain 70 g of copolymerized polycarbonate resin.

Synthesis Example 4 4,4'-(1-methylethylidene) in Synthesis Example 1
A polycondensation reaction was carried out in the same manner as in Synthesis Example 1, except that 0.08 mol of 4,4'-cyclohexylidene bisphenol was used instead of bisphenol, to obtain 70 g of copolymerized polycarbonate resin.

Synthesis Example 5 4,4'-(1-methylethylidene) in Synthesis Example 1
A polycondensation reaction was carried out in the same manner as in Synthesis Example 1, except that 0.08 mol of 4.4"-(cyclohexylidene)bis(2-methylphenol) was used instead of bisphenol.
70 g of copolymerized polycarbonate resin was obtained.

Synthesis Example 6 Instead of 3,3-bis(4-hydroxyphenyl)-1(311)-isobenzofuranone in Synthesis Example 1,
3.3-bis(3-methyl-4-hydroxyphenyl)
A polycondensation reaction was carried out in the same manner as in Synthesis Example 1 except that 0.12 mol of -1(311)-isobenzofuranone was used to obtain 70 g of copolymerized polycarbonate resin.

Synthesis Example 7 Instead of 3,3-bis(4-hydroxyphenyl)-1(311)-isobenzofuranone in Synthesis Example 1,
3.3-bis(3-methyl-4-hydroxyphenyl)
0.12 mol of -1(311)-isobenzofuranone was used, and 0.08 mol of 4.4'-(1-phenylethylidene)bisphenol was used instead of 4.4'-(1-methylethylidene)bisphenol. Except using
A polycondensation reaction was carried out in the same manner as in Synthesis Example 1 to obtain 70 g of copolymerized polycarbonate resin.

Synthesis Example 8 Instead of 3,3-bis(4-hydroxyphenyl)-1(311)-isobenzofuranone in Synthesis Example 1,
3.3-bis(3-methyl-4-hydroxyphenyl)
Using 0.12 mol of -1(3+1)-isobenzofuranone, and replacing 4.4'-(1-methylethylidene)bisphenol with 4.4'-(L-phenylethylidene)bis(2-methyl A polycondensation reaction was carried out in the same manner as in Synthesis Example 1, except that moles of O and OS (phenol) were used, to obtain 70 g of a copolymerized polycarbonate resin.

Synthesis Example 9 Instead of 3,3-bis(4-hydroxyphenyl)-1(311)-isobenzofuranone in Synthesis Example 1,
3.3-bis(3-methyl-4-hydroxyphenyl)
0.12 mol of -1(3+1)-isobenzofuranone was used, and 0.08 mol of 4.4'-cyclohexylidenebisphenol was used instead of 4.4'-(1-methylethylidene)bisphenol. A polycondensation reaction was carried out in the same manner as in Synthesis Example 1 except that 70 g of copolymerized polycarbonate resin was obtained.

Synthesis Example 10 Instead of 3,3-bis(4-hydroxyphenyl)-1(311)-isobenzofuranone in Synthesis Example 1,
3.3-bis(3-methyl-4-hydroxyphenyl)
0.12 mol of (311)-isobenzofuranone was used, and 4.4'-(cyclohexylidene) was used instead of 4.4'-(1-methylethylidene)bisphenol.
A polycondensation reaction was carried out in the same manner as in Synthesis Example 1 except that 0.08 mol of bis(2-methylphenol) was used to obtain a copolymerized polycarbonate resin of 70K.

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 copolymerized polycarbonate resins mentioned above, known binder resins such as polystyrene, polyvinyl chloride, polyvinyl acetate, vinyl chloride-vinyl acetate copolymers,
Conventionally known thermoplastic resins such as polyvinyl acetal, alkyd resin, acrylic resin, polyacrylonitrile, polycarbonate, polyamide, polyketone, polyacrylamide, butyral resin, polyester, thermosetting resin such as polyurethane, epoxy resin, phenol resin, etc. things can be used.

The thickness of the charge generation layer is usually set to 0.05 to 40 mm, preferably 0.05 to 25 mm.

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. Typical solvents used to form the charge transport layer include benzene, toluene,
Aromatic hydrocarbons such as xylene and chlorobenzene, halogenated aliphatic hydrocarbons such as methylene chloride, chloroform, and ethylene chloride, cyclic or linear ethers such as tetrahydrofuran and dioxane, or mixed solvents thereof. can be given.

The thickness of the charge transport layer is 2 to 100%, preferably 10 to 100%.
It is set to 40a+.

EXAMPLES Hereinafter, the present invention will be specifically explained with reference to Examples, but the present invention is not limited to these Examples.

Example 1 An aluminum pipe was used as a conductive substrate, and 10 parts by weight of polyamide resin, 150 parts by weight of methanol,
and 40 parts by weight of water, and dried.
A subbing layer having a thickness of 1 layer was formed. Furthermore, trigonal selenium (
A mixture consisting of 90 parts by weight (manufactured by Zero Rafusuf Co., Ltd., USA), 10 parts by weight of polyvinyl butyral resin, and 300 parts by weight of n-butanol was dispersed, and 2 parts by weight of n-butanol was added to 1 part by weight of the resulting dispersion to dilute it. The liquid was applied onto the above-mentioned undercoat layer and dried to form a charge generation layer having a thickness of 0.3 mm. Next, N,N'-diphenyl-N,N
3 parts by weight of '-bis(3-methylphenyl)-[t,i'-biphenyl-4,4'-diamine and 10 parts by weight of the polycarbonate resin obtained in the above synthesis example were added to 40 parts by weight of methylene chloride. The resulting solution was applied onto the above charge generation layer and dried to form a charge transport layer with a thickness of 20 mm, thereby producing an electrophotographic photoreceptor consisting of three layers.

When the electrophotographic photoreceptor produced as described above is installed in a copying machine equipped with a cleaning member and copies are made for 100,000 copies, is there any occurrence of image defects due to abrasion and scratches on the surface of the electrophotographic photoreceptor? , and the amount of surface wear were investigated, and the surface pencil hardness was also investigated. The results are shown in Table 1.

Examples 2 to 10 Electrophotographic photoreceptors were prepared in the same manner as in the above Examples, except that the copolymerized polycarbonate resin obtained in Synthesis Examples 2 to 10 was used as the binder resin for the charge transport layer. Each was evaluated in the same way. The results are shown in Table 1.

Comparative Example 1 The following structural formula (A) and (
An electrophotographic photoreceptor was prepared in the same manner as in Example 1, except that a copolycarbonate resin containing repeating units represented by B) at a molar ratio of 5:5 was used, and the electrophotographic photoreceptor was evaluated in the same manner. . The results are shown in Table 1.

Comparative Example 2 An electrophotographic photoreceptor was prepared in the same manner as in the above Example except that a polycarbonate resin consisting of a repeating unit represented by the following structural formula was used as the binder resin of the charge transport layer. We conducted an evaluation. The results are shown in Table 1.

Effects of the Invention In the present invention, since a polycarbonate resin consisting of repeating units represented by the above structural formula (1) is used as the binder resin of the photosensitive layer, the formed coating film has extremely excellent surface hardness. Therefore, the electrophotographic photoreceptor of the present invention has excellent durability and is free from image defects due to abrasion and scratches on the surface of the photosensitive layer. 5 (Suppressed and lifespan dramatically improved.

Patent applicant Fuji Xerox Co., Ltd. Agent
Patent Attorney Tsuyoshi Seibe Table 1

Claims (2)

[Claims] (1) In an electrophotographic photoreceptor comprising a photosensitive layer provided on a conductive substrate, the photosensitive layer contains, as a binder resin, a repeating unit represented by the following structural formula (I) and a repeating unit represented by the following structural formula (II).
, (III) or (IV). ▲There are mathematical formulas, chemical formulas, tables, etc.▼(I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(II) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(III) ▲There are mathematical formulas, chemical formulas, tables, etc.▼( IV) (wherein, X represents a hydrogen atom or an alkyl group, and R represents an alkyl group) (2) The content ratio of the repeating unit represented by the structural formula (I) to the repeating unit represented by the structural formula (II), (III) or (IV) is 10:90 to 90:10. An electrophotographic photoreceptor according to claim 1.