JPS59128545A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To stabilize electric characteristics during repeated uses by using an intermediate layer formed by dispersing the fine particles of a specified disazo pigment in an insulating resin. CONSTITUTION:An intermediate layer obtained by dispersing fine particles of a disazo pigment into an insulating resin and a photoconductive layer made of Se, an Se alloy, or an Se compd. are formed on a conductive substrate. Said pigment is represented by the formula as shown herein, in which X is an aromatic ring, such as a benzene or naphthalene ring, or a hetero ring, such as indole, carbazole or benzofuran ring, or its halogen substd. ring; R1 is an aromatic ring or a hetero ring, such as a carbazole or dibenzofuran ring, or a substituted ring thereof; R2 is H, lower alkyl, phenyl, or its substitute; and R1 may be substd. by lower alkyl, lower alkoxy, halogen, nitro, dialkyl amino, or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrophotographic photoreceptor having a photoconductive intermediate layer between a support and a selenium-based photoconductive layer.

2. Description of the Related Art Electrophotographic photoreceptors are known in which a conductive support is provided with an intermediate layer in which inorganic or organic fine particles are dispersed as dispersoids in an insulating resin binder, and a selenium-based photoconductive layer is provided thereon. In an electrophotographic photoreceptor having such a layered structure, the purpose of the intermediate layer is to improve the adhesiveness between the support and the photoconductive layer and to improve the electrical properties. Interlayers are generally classified into two types, low resistance interlayers and photoconductive interlayers, depending on the type of particles dispersed in the binder. Examples of the former include those using carzene as a dispersoid (Patent Publication No. 49-126339) and those using metals or chalcogen compounds (Japanese Patent Publication No. 54-3).
An example of the latter is one using phthalocyanine (Japanese Patent Publication No. 44-12671). However, in the former intermediate layer, electrical properties such as charging properties and residual potential of the photoreceptor vary greatly depending on dispersion conditions. Therefore, the challenge is to control the dispersion conditions. On the other hand, when the dispersoid is a phthalocyanine pigment in the latter intermediate layer,
There is a drawback that the electrical properties, particularly the residual potential, fluctuate during repeated use. As another intermediate layer that does not fit into the above classification, there is a known intermediate layer consisting of a non-crystalline resin alone without using a dispersoid (Japanese Patent Application Laid-open No. 103742/1983). The purpose is to inhibit crystallization in the photoconductive layer provided on the soil, and is different from the above two types of intermediate layers.

The object of the present invention is to ensure that the electrical properties of the dispersed particles used in the intermediate layer are stable even under the dispersion conditions and repeated use, and that the intermediate layer also has a sensitizing effect, a crystallization suppressing effect, and an effect of improving flexibility by improving adhesiveness. Another object of the present invention is to provide an electrophotographic photoreceptor having excellent electrophotographic properties.

That is, the present invention provides, on a conductive support, an intermediate layer in which fine particles of an organic pigment are dispersed in an insulating resin, and a photoconductive layer made of selenium, a selenium alloy, or a selenium compound thereon. In the electrophotographic photoreceptor, the organic pigment has the general formula (where is an aromatic ring such as a benzene ring or a naphthalene ring, a hetero ring such as a dibenzofuran ring or a carnoS sol ring, or a substituted product thereof;
represents hydrogen, a lower alkyl group, a phenyl group, or a substituted product thereof. ) It is characterized by being a disazo pigment shown in the following. Examples of substituents on the aromatic ring or heterocycle of It will be done. Examples of substituents on the phenyl group include halogen.

The present invention uses the disazo pigment represented by the above general formula as a dispersoid in the intermediate layer of an electrophotographic photoreceptor having a conductive support, an intermediate layer, and a photoconductive layer.

As the conductive support, for example, At! , Ni, stainless steel and other metals or metal oxide plates; M,
Insulating sheets such as synthetic paper and plastic films coated with metals such as , Pd and Au; paper or cloth impregnated with conductive substances such as polymeric 4M ammonium salts and 4-listyrene sulfonates are used.

The intermediate layer is mainly composed of an insulating resin and a disazo pigment of the above general formula. Examples of insulating resins include epoxy resin, acrylic resin, polyimide, etc. Examples include lyamide, butyral resin, polyester, etc. Among them, polyester and butyral resin give particularly good results. It is also possible to use two or more types of insulating resins for the purpose of supplementing the unique characteristics of these resins. On the other hand, specific examples of disazo pigments include the following.

As described above, disazo pigments can be easily produced according to known methods, for example, the method described in JP-A-52-4241.

The amount of the thus obtained disazo pigment dispersed in the insulating resin is suitably 1 to 50% by weight. If the amount of dispersion is too large than the above range, the adhesiveness will be reduced, resulting in a loss of flexibility improvement effect, and if it is too small, the residual potential will increase. The thickness of the intermediate layer is suitably 5μ or less, preferably 1μ.
~3μ. In addition to the above two components, other dispersoids may be added to the intermediate layer of the present invention in order to improve and stabilize various properties.

The photoconductive layer is composed of selenium, a selenium alloy, or a metal selenide. 5eT as a selenium alloy or selenium compound
e, As2Se3.5e-Bi gold alloy, 5e-8b alloy, and the like. The thickness of the photoconductive layer is suitably 100 microns or less, preferably 10 to 70 microns.

To make the photoreceptor of the present invention, an insulating resin solution in which the disazo pigment is dispersed is coated on a conductive support and dried to form an intermediate layer, and selenium, a selenium alloy, or a selenium compound is deposited on the intermediate layer. A photoconductive layer may be formed.

The present invention will be explained below by way of examples.

Example 1 Zotyral resin (XYHL manufactured by Niion Car/Nido Co., Ltd.)
4-weight cylinder 9 in a glass pot with 11 parts of tetrahydrofuran
Then, 1 part by weight of the disazo pigment of compound A1 and 2 parts of stainless steel were added to this instep.
Milled for 2 hours. 34 parts by weight of tetrahydrofuran was added to the obtained dispersion to prepare an intermediate layer forming liquid.

Next, pour this liquid onto stainless steel (SU 83041
Coated onto a support made of
An electrophotographic photoreceptor was formed by drying at 00°C for 1 hour to form an intermediate layer, and then vacuum-depositing selenium on the intermediate layer to form a photoconductive layer of amorphous selenium with a thickness of 60 μm. Created.

For comparison, the above Zotyral resin 1 was used as the intermediate layer forming liquid.
An electrophotographic photoreceptor was produced in the same manner except that a solution prepared by dissolving 9 parts by weight of tetrahydrofufurin was used.

Next, the above two types of photoreceptors were tested for electrophotographic characteristics, and the results shown in the table below were obtained.

Note) Vyt: 5KV corona discharge 2 on the sample surface
Surface potential when applied for 0 seconds.

D, D: Value of Vo/V'M (VO is the surface potential when dark decayed for 20 seconds).

After B1AH dark decay, light was irradiated with a tungsten lamp so that the surface illuminance was 20 lux K, and the surface potential was
Exposure g required to reach 0.

■R: Surface potential after 20 seconds of light irradiation.

As can be seen from this table, the effect of the intermediate layer in which the disazo pigment is dispersed in the photoreceptor of the present invention is clear, and in particular, a remarkable effect is observed in reducing the residual potential.

Example 2 Polyester (Bori Ester Atoheshizo manufactured by DuPont)
9 parts by weight were dissolved in 23 parts by weight of tetrahydrofuran in a glass bond, and 1 part by weight of the disazo pigment of Compound A3 and the same stainless steel Zeel as in Example 1 were added thereto and milled for 72 hours. Further, 63 parts by weight of tetrahydrofuran was added to the obtained dispersion to prepare an intermediate layer forming liquid. This solution was coated on the same support as in Example 1 so that the thickness after drying would be 3P, and dried at 100°C for 1 hour to form an intermediate layer. Amorphous 5e-Te alloy with a thickness of 60/l is formed by vacuum deposition of 5e-Te alloy.
A Shimiko photographic photoreceptor was produced by forming a photoconductive layer made of e-Te.

For comparison, a %11 photoreceptor was prepared in the same manner except that 11 copper phthalocyanine was used in place of the disazo pigment in the intermediate layer forming solution.

Insert these photoreceptors into a commercially available electrophotographic copying machine,
When a repeated use test was conducted, the initial residual type 1 position 20V increased by about 90V in the comparative product to 110cm, whereas no change in the residual type position was observed in the product of the present invention.

Claims (1)

[Claims] 1. An intermediate layer formed by dispersing fine particles of an organic pigment in an insulating resin on a conductive support;
In an electrophotographic photoreceptor provided with a photoconductive layer made of a selenium alloy or a selenium compound, the organic pigment has a general formula (where X is an aromatic ring such as a benzene ring or a naphthalene ring,
Heterocycles such as indole ring, carnozole ring, hensofuran ring, or substituted products thereof; R1 is an aromatic ring such as benzene ring, naphthalene ring, dibenzofuran ring, heterocycle such as carnozole ring, or substituted products thereof; , R2 represents hydrogen, a lower alkyl group, a phenyl group or a substituted product thereof. ) An electrophotographic photoreceptor characterized by being a disazo pigment represented by: