JPS6165252A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To improve the adhesiveness to a conductive substrate by using a phenoxy resin as a binder to a charge generating layer and to improve electrophotographic characteristics by using a copper phthalocyanine pigment for the charge generating material. CONSTITUTION:The phenoxy resin is dissolved in a suitable solvent and one or more kinds among alpha type, beta type, epsilon type copper phthalocyanine pigments are mixed and dispersed therein, by which a coating soln. is obtd. The coating soln. is coated on the conductive substrate and is dried to form the charge generating layer. The phenoxy resin dissolves in cyclic ethers such as tetrahydrofuran and dioxane, N, N-di-substd. amides such as dimethyl formamide and chlorine solvents such as tegrachlorethane but is insoluble in arom. org. solvents such as toluene, benzene, xylene and chlorobenzene and therefore said resin does not elute in the stage of forming a charge transfer layer and the charge generating layer which is satisfactory in terms of adhesiveness and film formability is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an improved electrophotographic photoreceptor, and more particularly to an improved laminated electrophotographic photoreceptor comprising a charge generation layer and a charge transport layer. .

Conventional structure and problems Conventionally, selenium, cadmium sulfide, zinc oxide, etc. have been known as photoconductive materials used in electrophotographic photoreceptors, but in recent years, in addition to these inorganic photoreceptors, organic photoconductive materials have also been used. Research into organic photoreceptors using materials has been actively conducted, and a laminated structure in which the photosensitive layer is functionally separated into a charge generation layer and a charge transport layer has been proposed in order to improve sensitivity and repeatability.

Until now, when forming a charge generation layer, binders such as polyvinylglycine, polyvinyl butyral, polystyrene, polybutadiene, styrene butadiene copolymer, polyester, polyamide, polyvinyl chloride,
Thermoplastic resins such as polyvinyl acetate, vinyl chloride-vinyl acetate copolymer, and acrylic resin are used. but,
Many of these binders are dissolved by the solvent in the coating solution used to form the charge transport layer, which makes it difficult to select a solvent when actually forming a layered structure of a charge generation layer and a charge transport layer. have. When a charge transport layer is laminated by a normal coating method on a charge generation layer using a binder resin soluble in general organic solvents, the charge generation layer is eluted by the solvent in the charge transport layer coating solution. , it may not be possible to form a charge generation layer. Moreover, since the charge generation layer is usually a thin layer with a thickness of several microns or less, it has the drawback that electrophotographic characteristics are significantly deteriorated by a slight elution.

OBJECTS OF THE INVENTION An object of the present invention is to provide a suitable binder for the charge generation layer used in the above-mentioned laminated structure, thereby improving the adhesion V between the conductive support and the photosensitive layer and improving the electrophotographic properties. The objective is to provide an excellent photoreceptor.

Structure of the Invention The electrophotographic photoreceptor of the present invention is an electrophotographic photoreceptor formed by laminating a charge generation layer and a charge transport layer on a conductive support.
By using phenokine resin as a binder in the charge generation layer, it has excellent adhesion between the conductive support and the photosensitive layer, and by using copper phthalonanine pigment as the charge generation substance, it has excellent electrophotographic properties. The present invention provides an electrophotographic photoreceptor.

Description of examples The electrophotographic photoreceptor of the present invention will be explained in detail below.

The electrophotographic photoreceptor (hereinafter referred to as photoreceptor) of the present invention has a laminated structure of a charge generation layer containing a phenoxy resin as a binder and a charge transport layer on a conductive support.

The conductive support used in the present invention may be a conventionally known conductive support, such as a metal plate such as aluminum, a plate made of a metal oxide such as tin oxide, or a metal or metal oxide thereof. The phenoxy resins used in the present invention include, for example, cyclic ethers such as tetrahydrofurano and dioxane, N, N such as dimethylformamide, etc. - Disubstituted amides, moieties that dissolve in chlorinated solvents such as tetrachloroethane, toluene, benzene,
Because it is insoluble in aromatic organic solvents such as xylene and chlorobenzene, it does not elute when forming a charge transport layer and has good adhesive properties.

A charge generation layer with good film formability can be formed.

In order to form the charge generation layer of the present invention, the phenokhine resin is dissolved in the above-mentioned appropriate solvent, and then α-type, β-type, ε-type
One or more types of copper phthalocyanine pigments are mixed and dispersed to obtain a coating solution. Dispersion methods include ball mill, roll mill, sand mill, attritor, and homogenizer.

Examples include ultrasonic dispersion. The coating solution thus obtained is coated onto a conductive support by a conventional coating method and dried to form a charge generation layer. The thickness of this charge generation layer is several microns to several tens of microns, preferably 0.2 to 2 microns.

The charge transport layer that can be used in the photoreceptor of the present invention includes pyrazolino,
Triphenylmethane, oxadiazole.

Electron-donating substances consisting of derivatives such as carbazole and imidazole; An acrylic resin is used as a charge transporting substance selected from electron-accepting substances such as 9-zineanomethylenefluorenone and 2,4°5.7-titranitroxant 7.

It is obtained by coating and laminating the charge generating layer together with a binder such as polyester or polycarbonate by a conventional coating method. The thickness of this charge transport layer is 2-100 microns, preferably 1
Preferably, it is 5 to 2Q microns.

Further, as the solvent used in forming the charge transport layer of the present invention, general organic solvents can be used, and examples of solvents that do not elute the phenokino resin include benzene, naphthalene, toluene, and xylene.

Aromatic hydrocarbons such as menthylene and chlorobenzene are effective.

Example 1 ε-type copper phthalocyanine pigment (Toyo Ink Co., Ltd.) 32 and 7
Ninoki 7 resin (PKHH manufactured by T!, C, C, USA) 37 was added to dioxane 1207, and after shaking with paint conditioner/funer for 3 hours using crow beads,
The glass beads were removed. The thus obtained dispersion was applied using a bar coater A5 and dried at 100° C. for 1 hour to form a charge generation layer with a thickness of 0.3 microns.

Then, 1-benzyl-1,2,3,4-tetrahydroquinol-7-6-carboxaldehyde-1'-amino-
1/, 2/, 37, 47-titrahydroquinoline, 8 parts by weight of hydrazone, 10 parts by weight of polycarbonate resin
The mixture was dissolved in 100 parts by weight of a solvent consisting of chlorobenzene and dichloroethane in a ratio of 3=2, and applied onto the charge generation layer using a blade V, followed by drying at 100'C for 2 hours. At this time, a photoreceptor was obtained in which a charge transport layer having a thickness of 15 microns was formed on the charge generation layer.

The resulting photoreceptor was repeatedly charged and exposed using a copying paper tester Model 5P-428 manufactured by Kawaguchi Electric Co., Ltd., and its properties were measured. Initial surface potential when corona charged at an applied voltage of -6 KV; V□ (volt).

The surface potential when left in the dark for 2 seconds after being charged is v2 (volt), and the dark decay potential for 2 seconds is dV (volt).

When irradiating 5 lux of white light at v2 1. +)
Exposure amount required to attenuate to V2: E3A (lux・i/!;) and residual potential 6 seconds after light irradiation; v
R6 (volts) was measured.

Further, the adhesion of the photosensitive layer to the support plate was determined by a peel test using Cellotape V.

As is clear from the results in Table 1, the electrophotographic photoreceptor of the present invention has a small dark decay potential due to repetition, maintains electrophotographic properties at an excellent level, and has excellent adhesive properties. The electrophotographic photoreceptor of the present invention has good durability.As described above, the electrophotographic photoreceptor of the present invention uses a phenoxy resin as a binder in the charge generation layer, so that the charge generation layer is not eluted during the formation of the charge transport layer. It's just like that,
A laminated photoreceptor with little deterioration of electrophotographic properties and excellent adhesiveness and film-forming properties can be obtained.

Claims (2)

[Claims] (1) An electrophotographic photoreceptor formed by laminating a charge generation layer and a charge transport layer on a conductive support, characterized in that the charge generation layer contains a phenoxy resin as a binder. Photoreceptor. (2) The electrophotographic photoreceptor according to claim 1, wherein the charge generation layer contains at least one pigment selected from α-type copper phthalocyanine, β-type copper phthalocyanine, and ε-type copper phthalocyanine.