JPS59127046A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To improve the electrical characteristics of an electrophotographic sensitive body obtd. by successively forming an intermediate layer contg. fine particles of an org. pigment dispersed in an insulating resin and a photoconductive layer of an Se compound on an electrically conductive support by using a specified disazo pigment as the org. pigment. CONSTITUTION:An intermediate layer contg. fine particles of an org. pigment dispersed in an insulating resin and a photoconductive layer of an Se compound are successively formed on an electrically conductive support. At this time, a disazo pigment represented by formula I [where A is a group represented by formula II or III (where each of X, Ar1 and Ar2 is a benzene ring or the like, R1 is H, lower alkyl or the like, and R2 is lower alkyl or the like)] is used as the org. pigment. The electrically conductive support is made of a metal such as Al or Ni, the oxide thereof, synthetic paper coated with the metal or metallic oxide, or the like. Since the intermediate layer consists essentially of the insulating resin and the disazo pigment represented by the formula I , the adhesive property of the photoconductive layer to the support and the electrical characteristics are improved.

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.

Intermediate photoreceptors are known in which fine inorganic or organic particles are dispersed as dispersoids in an insulating resin binder on a conductive support. 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 carmen as a dispersoid (% Publication No. 49-126339) and those using metals or chalcogen compounds (Japanese Publication No. 54-36859); is one using phthalocyanine (Special Publication No. 44-x26
There is a publication No. 71. 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, controlling the dispersion conditions is a challenge.

On the other hand, when the dispersoid in the latter intermediate layer is a 7-talocyanine pigment, there is a drawback that the electrical properties, particularly the residual potential, fluctuate during repeated use. Note that another intermediate layer that does not fall into the above category is known to be made of an amorphous resin alone without using a dispersoid (Japanese Patent Application Laid-Open No. 53-103742), but the purpose of this intermediate layer is to This is intended to suppress crystallization in the photoconductive layer provided on top of the photoconductive layer.
This 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 an intermediate layer in which fine particles of an organic pigment are dispersed in an insulating resin on a conductive support, and a photoconductive layer made of selenium, a selenium alloy, or a selenium compound thereon. In the electrophotographic photoreceptor, the organic pigment has a general formula (where X is an aromatic ring such as a benzene ring or a naphthalene ring, an indole ring, or a carnozole ring.

Heterocycles such as benzofuran rings or substituted products thereof,
Arl is an aromatic ring such as a tetrabenzene ring or a naphthalene ring, a heterocyclic ring such as dibenzofuran, or a substituted product thereof;
represents an aromatic ring such as a benzene ring or a naphthalene ring, or a substituted product thereof; R1 represents hydrogen, a lower alkyl group, a phenyl group, or a substituted product thereof; - represents a lower alkyl group, a carbyl group, or an ester thereof; ] It is characterized by being a disazo pigment shown in the following.

The substituent on the aromatic ring or heterocycle of group, Cal I xyl group, sulfonic acid group, or a salt thereof. As a substituent in the aromatic ring of Arc, [is Ay
In addition to the substituents in l, examples include an acylamino group. Further, examples of the substituent on the phenyl group of R8 include 10gen.

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.

Examples of conductive supports include plates made of metals or metal oxides such as An, Ni, and stainless steel; An, P;
d, insulating sheets such as synthetic paper coated with metals such as Au, and zotstic films; polymeric quaternary ammonium salts;
Paper or cloth impregnated with a conductive substance such as polystyrene sulfonate is used.

The intermediate layer is mainly composed of an insulating resin and a disazo pigment of the above general formula. Examples of the insulating resin include epoxy resin, acrylic resin, polyimide, polyamide, butyl resin, polyester, etc. Among them, polyester and zotyral 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.

The above-mentioned disazo pigments can be easily obtained according to known methods, for example, according to the method described in JP-A-56-9753.

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 adhesion will decrease, 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 5 μ or less, preferably 1 to 5 μm.
It is 3μ. In addition to the above two components, other dispersoids may be added to the intermediate layer of the present invention 1 in order to improve and stabilize various properties.

The photoconductive layer is composed of selenium, a selenium alloy, or a selenium compound. 5eT as a selenium alloy or selenium compound
e yAsl Se318 e B 1 alloy, 86-
Examples include sb alloy. 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 Butylene resin (XYHL manufactured by Union Carbide) 4
Part by weight was dissolved in 11 parts by weight of sodium hydroxide in a glass pot, and then 1 part by weight of the disazo pigment of Compound Mul and stainless steel Zeel were added thereto and milled for 72 hours. 34 parts by weight of Nato2HydroF2F was added to the obtained dispersion to prepare an intermediate layer forming liquid.

Next, this solution was applied onto a support made of stainless steel (5US304) so that the thickness after drying was lμ.
An electrophotographic photoreceptor was prepared by drying at ℃ for 1 hour to form an intermediate layer, and then vacuum-depositing selenium thereon to form a photoconductive layer made of amorphous selenium with a thickness of 60 μm.
I did.

For comparison, the intermediate layer forming liquid [butyral resin 1]
An electrophotographic photoreceptor was produced in the same manner except that a solution in which parts by weight were dissolved in 9 parts by weight of tetrahydrofuran 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: vM = surface potential when a 5KV corona discharge is applied to the sample surface for 20 seconds.

DD: VO/VM value (Vo is the surface potential when dark decayed for 20 seconds).

E: After dark decay, light is irradiated with a tungsten lamp so that the surface illuminance becomes 20.8 ux, and the amount of exposure required for the surface potential to become strong VO.

■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 (Polyester Adhesive manufactured by DuPont)
Disazo pigment 1 of compound 7i1 was dissolved in 23 parts by weight of tetrahydrofuran in a glass pot.
Parts by weight and the same stainless steel I-ru as in Example 1 were added 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. Next, this solution was coated on the same support as in Example 1 so that the thickness after drying was 3μ, and dried at 100°C for 1 hour to form an intermediate layer.
vacuum evaporated S/-Te alloy [60μ thick amorphous S]
An electrophotographic photoreceptor was produced by forming a photoconductive layer made of s-To.

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

Next, these photoreceptors are set in a commercially available electrophotographic copying machine,
When a repeated use test was conducted, the initial residual potential of 20V increased by approximately 90V to 110V in the comparison product, whereas no fluctuation in the residual potential was observed in the product of the present invention.

Claims (1)

[Scope of Claims] 1. An intermediate layer formed by dispersing fine particles of an organic pigment in an insulating resin on a conductive support, and further thereon a photoconductive layer formed of selenium, a selenium alloy, or a metal selenide. In the electrophotographic photoreceptor provided with
A hetero ring with an indole ring, car, 1 zole ring, benzofuran ring, or a substituted product thereof, Ar1 is a benzene ring,
Aromatic rings such as naphthalene rings, hetero rings such as dibenzofuran, or substituted products thereof, Arck! Aromatic rings such as benzene ring and naphthalene ring
& represents a lower alkyl group, carmexyl group, or an ester thereof). ] An electrophotographic photoreceptor characterized by being a disazo pigment represented by the following.