JPS62208051A - Lamination type electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To obtain a photosensitive body having high sensitivity by laminating an electric charge generating layer contg. a benzopyrylium salt of trimethine structure and nitrated poly-N-vinyl carbazole and electric charge transfer layer contg. a poly-N-vinyl carbazole on a conductive substrate. CONSTITUTION:The charge generating layer is constituted of the benzopyrylium salt of trimethine structure expressed by the formula and the nitrated poly-N- vinyl carbazole. R1 in the formula is hydrogen or phenyl group, R2 is hydrogen, p-methoxyphenyl group, R3 is hydrogen, methoxy group, nitro group, phenyl group, R4 is hydrogen, methoxy group, X is oxygen or sulfur atom. The nitrated poly-N-vinyl carbazole is substd. with 0.3-1 nitro groups per 10 carbazole rings. The poly-N-vinyl carbazole is incorporated into the charge transfer layer and these layers are laminated and deposited on an Al substrate or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a laminated electrophotographic photoreceptor containing an organic photoconductive substance.

2. Description of the Related Art Conventionally, photoreceptors made of inorganic photoconductive substances such as selenium, selenium-tellurium alloy, cadmium sulfide, and zinc oxide have been widely used as electrophotographic photoreceptors. In recent years, research has been progressing on organic photoconductive substances that are easy to synthesize and have the ability to select compounds that exhibit photoconductivity in an appropriate wavelength range.

An electrophotographic photoreceptor using an electroconductive material in the photosensitive layer is
It has advantages such as easy film formation, high flexibility and design freedom, low cost and no pollution, and is an electrophotographic process that is impossible with photoreceptors made of inorganic photoconductive materials. (for example, using a belt-shaped photoreceptor).

Among these, in order to improve sensitivity and photoreceptor life, a laminated electrophotographic photoreceptor was proposed in which the photosensitive layer was formed by separating the functions into a charge generation layer and a charge transport layer. Research is actively underway to improve and develop sensitization methods (for example, in the proceedings of the 16th Electrophotographic Society of Japan Seminar).

Problems to be Solved by the Invention However, at present, the above-mentioned organic photoreceptors do not fully satisfy the requirements for various electrophotographic photoreceptors. Therefore, it is desired to develop a highly sensitive electrophotographic photoreceptor that fully satisfies the characteristics required for an electrophotographic photoreceptor by taking advantage of the advantages of organic R1!1 materials.

Means for Solving the Problems In view of the above problems, the present invention provides a charge generating system containing a benzopyrylium salt having a trimethine structure represented by the structural formula (1) and a nitrated poly-N-vinylcarbazole. A highly sensitive electrophotographic photoreceptor is provided by laminating and forming a charge transport layer containing poly-N-vinylcarbazole on a conductive support.

(In the formula, R1 is hydrogen or a phenyl group, R2 is hydrogen or a p-methoxyphenyl group, R3 is hydrogen, methoxy group, nitro group, or phenyl group, R4 is hydrogen or a methoxy group, and X is an oxygen or sulfur atom. ).

Function The laminated electrophotographic photoreceptor of the present invention will be explained in detail below.

The charge generation layer of the laminated electrophotographic photoreceptor of the present invention comprises a benzopyrylium salt having a trimethine structure and a nitrated poly-
It can be obtained by adding N-vinylcarbazole or a suitable binder resin, dispersing or dissolving it, and coating it on a conductive support. Specifically, benzopyrylium salts having a trimethine structure include:
2-[3'-(3"-phenyl-25-penzobyranylidene)propenyl]-3-phenylbenzopyrylium verchlorate, 2-[3'-(3'-phenyl-8'
-methoxy-2'-benzopyranylidene)propenyl]
-3-phenyl-8-methoxyhenzopyrylium perchlorate, 2-[3'-(3",6'-diphenyl-2
1-penzobyranyritene)propenyl]-3.6-';
Phenylbenzopyrylium verchlorate, 2-[3'
-(3"-phenyl-6#-methoxy-2#-benzobyranylidene)propenyl]-3-phenyl-6-medoxybenzopyrylium verchlorate, 2-[3'-(3
'-phenyl-6''-nitro2#-benzopyranylidene)propenyl] -3-phenyl-6-nidropenzopyrylium verchlorate, 2-[3'-(4''-methoxyphenyl-2#- benzopyranylidene)propenyl]-4-methoxyphenylbenzobilylium verchlorate, 2-[3'-(3'-phenyl-41-methoxyphenyl-2''-benzovyranylidene)prohenyl]
-3-phenyl-4-methoxyphenylbenzopyrylium perchloride), 2-[3'-(3',6'-diphenyl-4#-methoxyphenyl-25-penzopyranylidene)propenyl]-3,6- Diphenyl-4-methoxyphenylbenzobilylium perchlorate, 2-[3
'-(4#-Methoxyphenyl-2'-penzothiapyranylidene) propenylgo 4-methoxyphenylbenzothiapyrylium perchlorate, 2-[3'-(3'-
Phenyl-4'-methoxyphenyl-2'-penzothiaviranylidene)propenyl]-3-phenyl-4-methoxyphenylbenzothiapyrylium perchlorate, 2
-[3'-(3',6'-diphenyl-4'-methoxyphenyl-2"-benzothiapyranylidene)propenyl]-3,6-diphenyl-4-methoxyphenylbenzothiapyrylium perchlorate is used. I can do it.

Nitrated poly-N-vinylcarbazole is one in which 0.3 to 1 nitro group is substituted for 10 carbazole rings, and poly-N-vinylcarbazole is dissolved in a mixed solvent of chlorobenzene and acetic acid. It can be easily synthesized by treating with nitric acid/acetic acid and then dipping into methanol. In addition, nitrated poly-N-vinylcarbazole is 0% per 1 part by weight of benzobyrylium salt.
．． It is used in an amount of 1 to 5 parts by weight, preferably 0.5 to 1 part by weight. Furthermore, although nitrated poly-N-vinylcarbazole alone has film-forming properties, it is necessary to use nitrated poly-N-vinylcarbazole for the purposes of improving adhesion between the charge generation layer and other layers, improving the uniformity of the coating film, and adjusting fluidity during coating. A binder resin can be used if necessary. Specifically, polyvinyl butyral.

polyvinyl acetate, polyvinyl chloride, polycarbonate,
Examples include acrylic resin, methacrylic resin, and copolymers of these resins. The amount of binder resin used is preferably 50% by weight or less of the weight of the charge generation layer, and
The solvent for dissolving the nitrated poly-N-vinylcarbazole and the binder resin is limited by the nitrated poly-N-vinylcarbazole, and specifically, chloroform.

Halogenated hydrocarbons such as methylene chloride, ethylene dichloride, and chlorobenzene can be used. Distributed, in this way! The Il coating solution is applied by a conventional coating method and dried by heating to form a charge generating layer with a thickness of several micrometers, preferably 0.2 to 2 micrometers.

The charge transport layer of the laminated electrophotographic photoreceptor of the present invention is obtained by applying a coating liquid in which poly-N-vinylcarbazole is dissolved as a charge transport agent onto the electrogenerating layer. Specifically, aromatic hydrocarbons such as toluene and xylene can be used as the solvent for preparing the coating liquid.

The thus prepared coating solution is applied by a conventional coating method and dried by heating to form a charge transport layer having a thickness of several μm to several tens of μm, preferably 5 to 25 μm.

The conductive support used in the laminated electrophotographic photoreceptor of the present invention may be any conventionally known conductive support, such as metal plates and drums made of aluminum, aluminum alloy, etc., and tin oxide.

These include plates made of metal oxides such as indium oxide, or various plastic films, papers, etc., to which such metals and metal oxides are attached by vacuum evaporation, sputtering, laminate coating, etc. and treated to make them conductive.

Furthermore, the charge generation layer and the charge transport layer constituting the laminated electrophotographic photoreceptor of the present invention have coating film flexibility and uniformity of 1.
In order to improve mechanical strength, plasticizers such as 0-terphenyl, epoxy compounds, phthalate esters, maleate esters, and chlorinated paraffins may be added. An adhesive or barrier layer, such as casein, polyvinyl alcohol, polyvinyl butyral, etc., can be provided between the conductive layer and the charge generating layer.

The electrophotographic photoreceptor of the present invention, which is formed by laminating the charge generation layer and the charge transport layer on the conductive support in this way,
Charge generation layer on conductive support, @.

Charge transport layers may be laminated sequentially, or a charge transport layer and a charge generation layer may be laminated in this order on a conductive support; the former is negatively charged and sensitive, and the latter is positively charged and sensitive. Although it has sensitivity, the former is more desirable from the viewpoint of surface film strength and durability.

EXAMPLES The present invention will be explained below using examples, but the present invention is not limited to the combinations shown in the examples below.

[Example 1] 1 part by weight of nitrated poly-N-vinylcarbazole, 0.05 part by weight of vinyl chloride-vinyl acetate copolymer (trade name: VMCH, manufactured by Union Carbide), and 2-[3'-
1 part by weight of (3'-phenyl-2'-penzopyranylidene)propenyl]-3-phenylbenzobilylium verchlorate was dissolved in 100,111 parts of ethylene dichloride.

This coating liquid was spin coated on an aluminum plate at 30 rpm,
1 part by weight of 0-order poly-N-vinylcarbazole (product name: Tubicol #210 manufactured by Seinan Koryo ■) which was dried at 80°C for 1 hour to form a charge generation layer with a film thickness of 0.3 μm and 0-order
0.3 parts by weight of terphenyl was dissolved in 10 parts by weight of toluene. This solution was applied onto the charge generation layer using a blade, and
It was dried at ℃ for 1 hour to form a charge transport layer with a thickness of 15 μm.

The laminated electrophotographic photoreceptor thus obtained was subjected to static fYt
Copy paper testing device (EPA-810 manufactured by Kawaguchi Electric Seisakusho Ql)
0), the surface potential V when charged at -5.5KV. (1+Q, surface potential V when left in a dark place for 1 second after that, (Vl, surface potential when exposed to white light of 51uχ Hv, exposure IB required to attenuate to (Vl)
! 4(Iuχ・5ee) and surface potential v after 6 seconds of exposure
R6M was measured for each. The measurement results are shown in Table 1.

[Example 2] 2-[3'-(3'-phenyl-2#-benzobilanylidene)propenyl]-3-phenylbenzobilylium verchlorate in Example 1 was replaced by (3
',6'-diphenyl-45-medoxyphenyl-2''
A photosensitive plate was prepared and its properties were measured using the same composition and method as in Example 1, except that -benzovyranylidene) propenyl 3-3-6-diphenyl-4-methoxyphenylbenzopyrylium verchlorate was used. Ta. Results first
Shown in the table.

[Example 3] 2-[3'-(3
“-phenyl-4#-methoxyphenyl-21-penzothiapyranylidene)propenyl]-3-phenyl-4-
A photosensitive plate was prepared and its properties were measured using the same composition and method as in Example 1, except that methoxyphenylbenzothiapyrylium verchlorate was used. The results are shown in Table 1.

[Example 4] For a comparative experiment, a sample was prepared with a composition that did not contain nitrated poly-N-vinylcarbazole during charge generation.

Vinyl chloride-vinyl acetate copolymer (manufactured by Union Carbide, trade name VMCH) 1! ! parts and 2-[3'
-(3'6"-diphenyl-4#-methoxyphenyl-
21-penzopyranylidene)propenyl]-3,-6-
One part by weight of diphenyl-4-methoxyphenylbenzopyrylium perchlorate was dissolved in one part by weight of ethylene dichloride.

A charge generation layer was formed using this coating liquid in the same manner as in Example 1. Further, the charge transport layer was also formed using the same composition and method as in Example 1.

The measurement results of the laminated electrophotographic photoreceptor thus obtained are shown in Table 1.

Effects of the Invention The laminated electrophotographic photoreceptor of the present invention has been described in detail above.
- a charge generation layer containing vinylcarbazole, and a charge transport amount containing poly-N-vinylcarbazole,
High sensitivity was achieved by laminating the film on a conductive support.

Claims (2)

[Claims] (1) A charge generation layer containing a benzopyrylium salt having a trimethine structure represented by the following structural formula (1) and nitrated poly-N-vinylcarbazole, and a charge transport layer containing poly-N-vinylcarbazole. 1. A laminated electrophotographic photoreceptor, characterized in that it is formed by laminating these on a conductive support. ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (1) (In the formula, R_1 is hydrogen or phenyl group, R_2 is hydrogen or p-methoxyphenyl group, R_3 is hydrogen, methoxy group, nitro group or phenyl group, R_4 is hydrogen or a methoxy group, where X represents an oxygen or sulfuric acid atom). (2) Claim (1) characterized in that the nitrated poly-N-vinylcarbazole is substituted with 0.3 to 1 nitro group per 10 carbazole rings.
The laminated electrophotographic photoreceptor described in .