JPS6290662A - Lamination type electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To obtain the titled body having a high sensitivity by laminating an electrostatic charge generating layer contg. a specific benzopyrylium salt and a poly-N-vinylcarbazole bromide (CZ) and an electrostatic charge transfer layer contg. CZ to form the electrophotographic sensitive body. CONSTITUTION:The electrostatic charge generating layer contains the benzo pyrylium salt shown by the formula wherein X is an oxygen or a sulfur atom, Y is an anionic group, (n) is 1 or 2, and CZ. And the electric charge transfer layer contains CZ. For example, the titled body is obtd. by laminating the elec trostatic charge generating layer which is formed by coating the 2-P- methoxystyryl-3-phenylbenzopyrylium salt and CZ on a substrate using a vinyl chloride-vinyl acetate copolymer as a binder, and the electrostatic charge trans fer layer contg. CZ in order. Thus, the titled body having the high sensitivity and the improved electrostatic chargeability and the reduced residual potential is obtd.

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 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 is an electrophotographic process that is not possible with photoreceptors made of inorganic photoconductive materials, and has advantages such as easy film formation, high flexibility and freedom of design, low cost, and non-pollution. (for example, using a heald-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 the condition and develop methods for exacerbating the condition. (For example, the Proceedings of the 16th Electrophotography Society Seminar).

Problems to be Solved by the Invention However, at present, the organic window photoreceptors described above 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 photoconductive materials.

Means for Solving the Problems In view of the above problems, the present invention provides a charge generation layer containing a benzopyrylium salt represented by the structural formula (1) and a brominated poly-N-vinylcarbazole, and a poly-N-vinyl carbazole. A highly sensitive electrophotographic photoreceptor is provided by laminating a charge rtI transport layer containing N-vinylcarbazole on a conductive support.

In the formula, n is an integer of 1 or 2, X represents an oxygen or sulfur atom, and Y represents an anionic functional group).

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

The charge generation layer of the electrophotographic photoreceptor of the present invention comprises a benzopyrylium salt and a brominated poly-N-vinylcarbazole.
Alternatively, it can be obtained by adding a suitable binder resin, dispersing or dissolving it, and coating the resultant on a conductive support. Brominated poly-N-vinylcarbazole is
One carbazole ring is substituted with 0.5 to 2 bromines, and an equivalent amount of poly-N-vinylcarbazole is prepared in a mixed solvent of chlorobenzene and benzene in the presence of a small amount of benzoyl peroxide. It can be easily synthesized by treating with N-bromsuccinimide, heating, and then pouring into methanol.

Further, brominated poly-N-vinylcarbazole is used in an amount of 0.1 to 5 parts by weight, preferably 0.5 to 1 part by weight, per 1 part by weight of henzobyrylium salt.

Furthermore, although brominated poly-N-vinylcarbazole alone has film-forming properties, it is necessary to improve the adhesion between the charge generation layer and other layers, improve the uniformity of the coating film, and adjust fluidity during coating. , a binder resin can be used if necessary. Specifically, polyvinyl butyral, polyvinyl octate, polyvinyl chloride, polycarbonate, acrylic resin,
Examples include methacrylic resins and copolymers of these resins. The amount of binder resin used is preferably 50 times or less of the weight of the charge generating layer. Also, brominated poly-
Solvents for dissolving N-vinylcarbazole and binder resin are limited to brominated poly-N-vinylcarbazole, but specifically include halogenated hydrocarbons such as chloroform, methylene chloride, and ethylene dichloride; Halogenated aromatics such as lobenzene and the like can be used. The coating liquid thus dispersed and prepared is applied by a normal coating method and dried by heating to form a charge generation layer with a thickness of several μm, preferably 0.2 to 2 μm. It is better to do so.

The charge transport layer of the laminated electrophotographic photoreceptor of the present invention includes poly-N-vinylcarbazole as a charge transport agent on the charge generation layer. It can be obtained by coating a coating liquid prepared under 8. Specifically, aromatic hydrocarbons such as toluene and xylene can be used as the l8 mixture for adjusting the coating three times.

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, including metal plates and drums made of aluminum, aluminum alloy, tin oxide, tin oxide, etc. These include plates made of metal oxides such as indium, or various types of plastic films, which are made by adhering such metals and metal oxides by vacuum evaporation, sputtering, lamination, 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 flexibility, uniformity,
Plasticizers such as 0-terphenyl, epoxy compounds, phthalic esters, maleic esters, and chlorinated paraffins may be added to improve the plate strength. Further, as in a typical electrophotographic photoreceptor, an adhesive layer or barrier layer of casein, polyvinyl alcohol, polyvinyl butyral, etc. can be provided between the conductive layer and the charge generation layer.

In this way, the laminated electrophotographic photoreceptor of the present invention is formed by laminating the charge generation layer and the charge transport layer on the conductive support. They may be laminated one after another, or a charge transport layer and a charge generation layer may be laminated in this order on a conductive support. The former case has sensitivity when charged negatively, and the latter case has sensitivity when charged positively, but the former is more desirable in terms 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 brominated poly-N-vinylcarbazole, 0.05 part by weight of vinyl chloride-vinyl acetate copolymer (manufactured by Union Carbide, trade name: VMCH), and 2-p-methoxystyryl-3- 1 part by weight of phenylbenzopyrylium and barchlorate was dissolved in 100 parts by weight of ethylene dichloride. This coating liquid was spin-coated on an aluminum plate at 30 rpm and dried at 80° C. for 1 hour to form a charge generation layer with a thickness of 0.3 μm.

Next, poly-N-vinylcarbazole (manufactured by Anan Koryo ■)
1 part by weight of Tubicol (trade name: Tubicol #210) and 0-terphenyl O, , [II were dissolved in 1 part by weight of toluene. This liquid was applied onto the charge generation layer with a blade and dried at 80° C. for 1 hour to form a charge transport layer with a thickness of 15 μm.

The surface potential V0 when the thus obtained laminated electrophotographic photoreceptor was charged at -5.5 KV using an electrostatic copying paper tester (EPA-8100 manufactured by Kawaguchi Electric Seisakusho)
(■), surface potential V when left in a dark place for 1 second
, (V) , 5LLIK surface potential when exposed to white light! Exposure amount EIA (lu 5ec) required to attenuate to 4V1 (V), surface potential v after 6 seconds of exposure
R6(v) was measured.

The measurement results are shown in Table 1.

[Example 2] 2-3', 4 instead of 2-p-methoxystyryl-3-phenylhenzopyrylium and verchlorate in Example 1
A window light plate was prepared and its properties were measured using the same composition and method as in Example 1, except that '-dimethoxystyryl-3-phenylhenzopyrylium and perchlorate were used. The results are shown in Table 1.

[Example 3] Except that 2-p-methoxystyryl-3-phenylbenzothiapyrylium verchlorate was used instead of 2-p-methoxystyryl-3-phenylbenzopyrylium verchlorate in Example 1, Composition similar to Example 1,
A photosensitive plate was prepared using the method and its characteristics were measured. The results are shown in Table 1.

[Example 4] For a comparative experiment, brominated poly(IJ-N) was added in the charge generation layer.
- A sample was prepared with a composition that did not contain vinyl carbazole.

1 part by weight of vinyl chloride-vinyl acetate copolymer (manufactured by Union Carbide Co., trade name: VMCH) and 1 part by weight of 2-1-methoxystyryl-3-phenylhendupyrylium, barchlorate were dissolved in 100 parts by weight of ethylene dichloride. . A charge generation layer was formed using this coating liquid in the same manner as in Example 1. The electric transport layer also had the same composition as in Example 1.

It was formed using a method.

The thus obtained laminated electrophotographic photoreceptor was subjected to the same measurements as in Example 1 using an electrostatic copying paper tester. The results are shown in Table 1.

Table 1 Effects of the Invention As above, the laminated electrophotographic photoreceptor of the present invention has been explained in detail. High sensitivity was achieved by laminating a charge generation layer containing poly-N-vinylcarbazole and a charge transport layer containing poly-N-vinylcarbazole on a conductive support. moreover,
It was possible to obtain an electrophotographic window illuminator using an organic photoconductive substance that has good chargeability and low residual potential, and satisfies the characteristics required for electrophotography.

Claims (2)

[Claims] (1) A charge generation layer containing a benzopyrylium salt represented by the following structural formula (I) and a brominated poly-N-vinylcarbazole, and a charge transport layer containing a poly-N-vinylcarbazole are electrically conductive. A laminated electrophotographic photoreceptor characterized by being formed by laminating on a transparent support ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (I) (In the formula, n is an integer of 1 or 2, and X is an oxygen or sulfur atom, Y represents an anionic function). (2) The laminated type according to claim 1, wherein the brominated poly-N-vinylcarbazole is substituted with 0.5 to 2 bromines per carbazole ring. Electrophotographic photoreceptor.