JPS6162044A - Electrophotografic sensitive body - Google Patents

Abstract

PURPOSE:To obtain an electrophotographic sensitive body having excellent flexibility, surface hardness and wear resistance by incorporating a copolymer compd. consisting of a specific material as a flexible auxiliary agent into a surface protective layer to form said layer. CONSTITUTION:The electrophotographic sensitive body is formed by laminating successively a photoconductive layer and surface protective layer on a conductive substrate. The surface protective layer includes the layers formed by dispersing a metallic oxide into various thermosetting resins and a polyurethane resin of a polyol setting type is used as the thermosetting resin. The copolymer compd. consisting of methyl methacrylate, styrene and octyl acrylate is incorporated as the flexible auxiliary agent into the thermosetting resin. The surface protective layer which has the extremely high flexibility without spoiling the excellent surface hardness and wear resistance intrinsic to the thermosetting resin at all and has the extremely good performance with respect to electrophotographic characteristics is thus obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an electrophotographic photoreceptor, and more specifically, to an electrophotographic photoreceptor having a protective layer on the surface of a photoconductive layer. It is related to.

[Prior art]

Photoreceptors used in electrophotography, which includes processes such as charging, exposure, development, transfer, and cleaning, include:
Many of them have been put into practical use, for example, as disclosed in US Pat. No. 2,297,619. For example, an organic photoconductive material is directly provided on a suitable conductive substrate by coating or vapor deposition, or a material is provided with a suitable organic binder, or an inorganic material such as ZnD, CdS, T+112, etc. is provided in the binder. Dispersed photoconductive materials or vapor-deposited materials such as first-generation regular selenium or its alloys are used (for example, Japanese Patent Publication No. 45-5394, Japanese Patent Publication No. 46-3005,
(See Japanese Patent Publication No. 49-14271). The surface layer of these photoreceptors is constantly subjected to mechanical, electrical and chemical stress during repeated use within an electrophotographic copying apparatus. For this reason, various proposals have been made to provide a surface protective layer on the surface of the photoreceptor in order to prevent damage to the surface of the photoreceptor and extend its life. One of these surface protective layers is a layer containing a thermosetting resin such as phenol resin, Epoquine resin, or alkyd resin, and is given appropriate conductivity!
In the electrophotographic photoreceptor used in the Carlson process, excellent improvement effects have been found in terms of surface hardness and abrasion resistance. However, when a film of -1- thermosetting +6+ resin is used as a surface protective layer on, for example, a sheet-shaped photoreceptor, there is a problem with respect to the flexibility of the film, in that a material that can be sufficiently absorbed by bacteria cannot be completely absorbed. are doing.

[Purpose of the invention]

An object of the present invention is to provide an electrophotographic photoreceptor that can reliably eliminate such problems.

[Structure of the invention]

As a result of various studies, the present inventor added an appropriate amount of a copolymer compound consisting of methyl methacrylate, styrene, and octyl acrylate as a flexibility auxiliary agent to a thermosetting resin, more specifically, a polyol-curable polyurethane resin. By containing the thermosetting resin, it has extremely excellent flexibility without impairing the excellent surface hardness and abrasion resistance inherent to the above-mentioned thermosetting resin, and also has extremely good performance in terms of electrophotographic properties. It has been discovered that a layer can be formed on an electrophotographic photoreceptor.

That is, the present invention provides an electrophotographic photoreceptor in which a photoconductive layer and a surface protective layer are sequentially laminated on a conductive substrate, wherein the surface protective layer is made of a polyol-curable polyurethane resin, and methyl methacrylate, methyl methacrylate, This is an electrophotographic photoreceptor characterized by containing a copolymer compound consisting of styrene and octyl acrylate.

The photoconductor used in the present invention includes, for example, amorphous selenium or an alloy thereof deposited on a suitable conductive substrate, or a binder containing 2nll, Cd, etc.
Dispersed inorganic photoconductive materials such as S, Ti112, etc., or organic photoconductors such as poly-N-vinylcarbazole (PVK), PVK and 2. /l,'l
-) Includes a charge transfer type complex with linitrofluorenone, a photoconductor in which a pigment such as fucrocyanine is dispersed in a binder, and a functionally separated photoconductor in which a charge generation layer and a charge transfer layer are laminated.

The surface protective layer used in the present invention is
There is a product in which a metal oxide is dispersed in a divine thermosetting resin as disclosed in Japanese Patent No. 7-30846,
As thermosetting resin, polyether polyol curing type,
A polyester polyol-curing type or acrylic polyol-curing type polyurethane resin is used.

The present invention is characterized in that a copolymer compound consisting of methyl methacrylate, styrene, and octyl acrylate is contained as a flexibility auxiliary agent in the thermosetting resin.
The suitable composition of this copolymer compound is 20 to 60 parts by weight of methyl methacrylate, 10 to 30 parts by weight of styrene, and 10 to 70 parts by weight of octyl acrylate.

The content of the above-mentioned copolymer compound in the above-mentioned polyol-curable polyurethane resin is suitably 0.1 to 50 parts by weight, and when the content is 2 to 30 parts by weight, it can be used as a surface protective layer on an electrophotographic photoreceptor. The effect is particularly remarkable when a film is formed.

The present invention will be explained below with reference to Examples.

(Example 1) A dispersion of Guianpuru-(CI21180) dispersed in tetrahydrofuran was coated on a support made of aluminum lamura vapor-deposited on a polyester film to a thickness of 0.5μ.
A charge generation layer was obtained. A solution prepared by dissolving 2 parts of hydrazone represented by structural formula (1) and 3 parts of polycarbonate resin in tetrahydrofuran was applied onto this to obtain a charge transport layer having a thickness of 15 μm.

Structural formula (1) Furthermore, 35 parts by weight of tin oxide with a particle size of 0.1μ or less was added to 65 parts by weight of a polyester polyol curable resin (manufactured by Kansai Paint Co., Ltd., Rethane 2000) and a copolymer compound (methyl mech). After dispersing in 60 parts by weight of acrylate, 30 parts by weight of styrene, 10 parts by weight of octyl acrylate (Nippon Zeon, TR-0fli28>10 parts by weight), the film thickness after drying is 2μ by dipping. A surface protective layer was applied as described above.The electrophotographic photoreceptor having the surface protective layer coated in this way was mounted on Fuji Xerox Co., Ltd.!
Repeated 50,000 times.

As a result, no wear and tear deterioration of the surface protective layer was observed even after 150,000 images were printed. At the same time, it is also possible to image 1500 regarding the occurrence of cracks in the surface protective layer caused by insufficient flexibility of the surface protective layer.
After 00 times, no occurrence occurred, and extremely clear images were obtained in January that were comparable in quality to the initial image quality.

In addition, in the photoreceptor that was prepared at the same time and did not contain the copolymer compound TR-0628 in the surface protective layer, many fine cracks were generated in the surface protective layer after image formation was repeated 20,000 times. Significant deterioration of the image was observed.

(Example 2) The polyester polyol curable resin (manufactured by Kansai Paint Co., Ltd., Rethan 2000> of Example 1 was mixed with acrylic polyol curable type +#t II (manufactured by Kansai Paint Co., Ltd., Rethan 400).
A photoreceptor with a surface protective layer was prepared in exactly the same manner as in Example 1 except that the photoreceptor was changed to 0), and was mounted on FX-1075 manufactured by Fuji Xerox Co., Ltd., and image formation was repeated 150,000 times.

As a result, no wear and tear deterioration of the surface protective layer was observed even after 150,000 images were printed.

At the same time, regarding the occurrence of cracks in the surface protective layer caused by insufficient flexibility of the surface protective layer, no cracks were observed after 150,000 images, and 15 extremely clear images were obtained.

It should be noted that TR-0 was included in the surface protective layer prepared at the same time.
For photoreceptors that do not contain 628, the image output is 200
After repeating the process 00 times, many fine cracks were generated in the surface protective layer and significant deterioration of the image was observed.

〔Effect of the invention〕

According to the present invention, it is possible to obtain an electrophotographic photoreceptor having a surface protective layer having excellent flexibility, surface hardness, and abrasion resistance, and having excellent electrophotographic properties.

Claims (1)

[Claims] In an electrophotographic photoreceptor in which a photoconductive layer and a surface protective layer are sequentially laminated on a conductive substrate, the surface protective layer is made of a polyol-curable polyurethane resin, and the resin contains methyl methacrylate, styrene, and octyl acrylate. A photoreceptor for electrophotography, characterized in that it contains a copolymer compound consisting of: