JPS59139040A - Photosensitive body for electrophotography - Google Patents

Abstract

PURPOSE:To obtain a photosensitive body for electrophotography having stable electric characteristics, improved sensitizing effect, and crystallization retarding effect of the photoconductive layer by providing a layer contg. fine particles of specified disazo pigment dispersed in an insulative resin between a conductive supporting body and an Se photoconductive layer. CONSTITUTION:An intermediate layer contg. fine particles of pigment expressed by the general formula I : [wherein A is a group expressed by the formula II or III; X us an aromatic ring such as benzene ring, heterocyclic ring such as indole ring or substituted body thereof; Ar<1> is an aromatic ring such as benzene ring, heterocyclic ring such as dibenzofuran ring or substituted body thereof; Ar<2> is an aromatic ring such as benzene ring or substituted body thereof; R<1> is H, lower alkyl, (substituted) phenyl; R<2> is lower alkyl, COOH or an ester thereof] dispersed in butyral resin, etc. between a conductive supporting body and an Se photoconductive layer. In this way, a superior photosensitive body for electrophotography is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrophotographic photoreceptor, and particularly relates to an electrophotographic photoreceptor in which a specific photoconductive intermediate layer is provided between an isoelectric support and a selenium-based photoconductive layer. Regarding the body.

Quiz's electrophotographic photoreceptor, in which an intermediate layer in which inorganic or organic fine particles are dispersed as a dispersoid in an insulating resin binder is provided on a conductive support, and a selenium-based photoconductive layer is further provided on the intermediate layer. is publicly known.

In an electrophotographic photoreceptor constructed with such layered electrodes,
The purpose of providing the intermediate layer is to improve the adhesion between the support and the photoconductive lead 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 (Japanese Unexamined Patent Publication No. 126339/1982) and those using metals or chalcogen compounds (Japanese Patent Publication No. 36859/1989); For example, there is a method using phthalocyanine (Japanese Patent Publication No. 12671/1983). However, in the former intermediate layer, the electrical properties of the photoreceptor, such as impedance, percent property, and residual potential, become thick (variable) depending on the dispersion conditions.

Therefore, controlling the FtQ conditions is a difficult issue. On the other hand, even in the latter intermediate layer, when the dispersoid is a 7-talocyanine pigment, there is a drawback that the electrical properties, particularly the residual potential, fluctuate during repeated use. In addition, as another intermediate layer that does not belong to the above category, one made of amorphous resin alone without using a dispersoid is known (Japanese Patent Application Laid-open No. 103742/1983); Its purpose is to control crystallization in the photoconductive layer provided thereon, and is different from the above two types of intermediate layers.

The purpose 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 has improved flexibility due to the sensitizing effect, crystallization suppressing effect, and improved adhesion. It is an object of the present invention to provide an electrophotographic photoreceptor that has both effects and excellent electrophotographic properties.

That is, the present invention provides an intermediate layer formed by dispersing fine particles of an organic pigment in an insulating resin on a conductive support, and further includes a photoconductive layer made of selenium, a selenium alloy, or a selenium compound. In the electrophotographic photoreceptor provided with or a substituted product thereof, Ar' is an aromatic ring such as a benzene ring or a naphthalene ring, a heterocycle such as a dibenzofuran ring, or a substituted product thereof, Ar2 is an aromatic ring such as a benzene ring or a naphthalene ring, or a substituted product thereof, R1 is hydrogen, a lower alkyl group, a phenyl group or a substituted product thereof, R2
represents a lower alkyl group, carzexyl group or an ester thereof. )] It is characterized by being a disazo pigment represented by

In the above, 1a in the aromatic ring or heterocycle of X
Examples of the substituent or substituent on the phenyl group of R1 include halogen, and examples of the substituent on the aromatic ring or heterocycle of Ar' or the substituent on the aromatic ring of Ar2 include halogen, lower alkyl group, and lower alkoxy group. , a lower dialkylamino group, a nitro group, a cyan group, a carxyl group, a sulfone-substituted group, or a carrier thereof.

To explain the present invention in more detail below, the electrophotographic photoreceptor of the present invention has a conductive support, an intermediate layer, and a photoconductive layer, and the dispersoid in the intermediate layer is represented by the above general formula. It uses a specific disazo pigment.

As the conductive support, for example, a slope made of metals such as Al and Ni or their metal ferrites, and stainless steel;
Examples include synthetic paper or plastic film coated with metals such as Al, PB, and Au; paper or cloth impregnated with tetraelectric substances such as polymeric quaternary ammonium salts and polystyrene sulfonates; It is not limited.

As described above, the photoconductive layer is formed of selenium, a selenium alloy, or a selenium compound.

Typical selenium alloys or selenium compounds are 5
eTe, As25a3, 5s-Bi gold alloy 5e-
Examples include 8b alloy, but are of course not limited to these (any material that has been conventionally employed as a photoconductive layer of a selenium-based electrophotographic photoreceptor can be used. The thickness of this photoconductive layer is 100 μm
The following is suitable, preferably 10 to 70 μm.

The intermediate layer is mainly composed of an insulating resin as a dispersion medium and a disazo pigment represented by the above general formula as a dispersoid. Examples of the insulating resin here include:
Examples include epoxy resins, acrylic resins, polyimide resins, polyamide resins, butyral resins, and polyester resins, among which the use of polyester resins and butyral resins provides particularly good results.

Furthermore, it is also possible to use two or more types of these resins in combination for the purpose of supplementing their unique properties.

On the other hand, specific examples of the disazo pigment include the following compounds, but the invention is of course not limited to these.

All of these disazo pigments are known substances, and can be easily synthesized and obtained from, for example, the method described in JP-A-56-9752.

The appropriate dispersion of the disazo pigment in the insulating resin is such that the disazo pigment occupies the intermediate layer in an amount of 1 to 50% by weight. If the amount of the disazo pigment in the intermediate layer is less than 1 part by weight, the resulting photoreceptor will have an increased residual potential, whereas if it is more than 500 parts by weight, the adhesion of the intermediate layer itself will decrease. However, as a result, the effect of improving the flexibility of the obtained photoreceptor cannot be expected.

The thickness of such an intermediate layer is suitably 5 μm or less, preferably about 1 to 3 μm. In addition to the above-mentioned two components (insulating resin and disazo pigment), suitable additives are added to this intermediate layer in order to improve and stabilize various properties of the intermediate layer or photoreceptor. Good too.

In order to actually produce the photoreceptor according to the present invention, an intermediate layer forming solution is prepared by dispersing the above-mentioned disazo pigment in an insulating resin solution, and this is coated onto a conductive support by a known method and dried. An intermediate layer may be formed on this intermediate layer, and selenium, a selenium alloy, or a selenium compound may be formed as an optical isoelectric layer on this intermediate layer by a conventional method such as a vapor deposition method or a sintering method. Note that the solvents used for preparing the intermediate layer forming solution include nato-2hydrofuran, dimethylformamide, methyl ether ketone, methyl cellosolve, benzene,
Examples include toluene and xylene.

Thus, the electrophotographic photoreceptor of the present invention can fully achieve its intended purpose.

Next, examples and comparative examples will be shown.

Example 1 Butyral resin (manufactured by Union Curtumide).

4 parts by weight of XYHL) were dissolved in 11 parts by weight of tetrahydrofuran in a glass pot, and then compound A was added thereto.
1 part by weight of disazo pigment and stainless steel ball were processed for 72 hours! J I got 7. Thirty-four overlapping portions of tetrahydrofuran were added to the obtained dispersion to prepare an intermediate layer forming liquid.

Next, this liquid was applied onto a support made of stainless steel (SUS304) so that the thickness after drying was approximately 1 μm,
An intermediate layer is formed by drying at 100°C for 1 hour, and selenium is further vacuum-deposited on top of the intermediate layer to form a photoisoelectric layer made of amorphous selenium with a thickness of about 60 μm. A body (product 1 of the present invention) was prepared.

For comparison, the same procedure was used as the intermediate layer forming liquid, except that the addition of the disazo pigment was omitted and a solution prepared by dissolving 1 part of the butyral@fat in 9 parts of tetrahydrofuran was used. A photoreceptor (comparative product 1) was prepared.

Subsequently, electrophotographic properties of these two types of photoreceptors were tested, and the results shown in Table 1 were obtained. Clothes
As can be seen from No. 1, the effect of the intermediate layer in which the disazo pigment is dispersed in the photoreceptor of the present invention is obvious, and in particular, a remarkable effect is observed in reducing the residual potential.

Table-1 Note) VM: Apply 5KV corona discharge to the sample surface for 20 minutes.
Second row, the surface potential when it becomes.

D, D: Vo/VM value (Vo is the surface potential when darkened for 20 seconds).

8%: After dark decay, light is irradiated with a tungsten lamp so that the illuminance on the second side becomes 20 lux, and the amount of exposure required for the surface potential to become % of Vo.

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

Example 2 9 parts by weight of polyester (manufactured by DuPont, Polyester Adhesive) were mixed with 23 parts by weight of tetrahydrofuran in a glass pot.
The disazo pigment 1 of compound A1 is dissolved in the heavy lid part, and disazo pigment 1 of compound A1 is dissolved therein.
The same parts by weight and stainless steel zel as in Example 1 were added and milled for 72 hours. Further, 63 parts by weight of tetrahydroflough was added to the obtained dispersion to prepare an intermediate layer forming liquid. Next, this solution was coated on the same support as in Example 1 to a dry thickness of about 3 μm, and dried at 100°C for 1 hour to form an intermediate layer. A 5e-Te alloy with a To content of 8% by weight was vacuum deposited to a thickness of about 60%.
An electrophotographic photoreceptor (product 2 of the present invention) was prepared by forming a photoconductive layer made of amorphous 5e-Te of .mu.m.

For comparison, an electrophotographic photoreceptor (comparative product 2) was prepared in exactly the same manner except that β-copper 7-talocyanine was used instead of the disazo pigment in the intermediate layer forming solution.

Subsequently, these two types of photoreceptors were set in a commercially available electrophotographic copying machine and a repeated use test was conducted, and it was found that the initial residual potential of comparative product 2 increased by approximately 90V to 110V, whereas this product increased by approximately 90V. In invention product 2, no fluctuation in residual potential was observed.

Claims (1)

[Claims] 1. Electrophotography in which an intermediate layer made of fine particles of organic pigment dispersed in an insulating resin is provided on a conductive support, and a photoconductive layer made of selenium, a selenium alloy, or a selenium compound is further provided thereon. In the photoreceptor, the organic pigment has the following general formula; ring, an aromatic ring such as a naphthalene ring, a heterocycle with a dibenzofuran ring, or a substituted product thereof, Ar” is an aromatic ring such as a benzene ring or a naphthalene ring, or a substituted product thereof, R1 is hydrogen, a lower alkyl group, phenyl or a substituted product thereof, R represents a lower alkyl group, a carxyl group, or an ester thereof.