JPS59139042A - Photosensitive body for electrophotography - Google Patents

Abstract

PURPOSE:To obtain a photosensitive body for electrophotography having stable electric characteristics, improved sensitizing effect, crystallization retarding effect and flexibility 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 Ar is a (substituted)phenyl, naphthyl, anthryl, pyrenyl, pyridyl, thienyl, furyl or carbazolyl substituted by halogen, lower alkyl, lower alkoxy, lower dialkylamino, NO2, OH, dibenzylamino, etc.] dispersed in an insulative synthetic resin such as butyral, is provided between a conductive supporting body and a photoconductive layer comprising Se(alloy) or Se compd. In this way, a photosensitive body having improved adhesion between each layers and superior electrophotographic characteristics is obtd.

Description

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

An electrophotographic photoreceptor is a type 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. It is publicly known. In an electrophotographic photoreceptor having such a layered structure, the purpose of providing an 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 cardan as one dispersoid (Japanese Unexamined Patent Publication No. 126339/1982) and those using metals or chalcogen compounds (Japanese Patent Publication No. 3685/1983).
9, and an example of the latter is one using phthalocyanine (Japanese Patent Publication No. 12671/1971).
There is. However, in the former intermediate layer, electrical properties such as charging characteristics and residual potential of the photoreceptor vary greatly depending on the dispersion conditions. Therefore, the challenge is to control the one-dispersion condition.

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, other intermediate layers that do not belong to the above category are those made of amorphous resin alone without using dispersoids (Japanese Patent Laid-Open No. 5
3-103742), but the purpose of the intermediate layer here is intended to suppress crystallization in the photoconductive layer provided thereon, and unlike the intermediate layer of 2ffi mentioned above, ·ing.

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 a sensitizing effect, a crystallization suppressing effect, and an improving flexibility effect due to improved adhesiveness. It is an object of the present invention to provide an electrophotographic photoreceptor that also has excellent electrophotographic properties.

That is, in the present invention, an intermediate layer made of fine particles of an 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 electrophotographic photoreceptor provided, the organic pigment has the following general formula (where Ar is a substituted or unsubstituted phenyl group, phthyl group, anthryl group, pyrenyl group, bilinadyl group, chenyl group, furyl group, or carbazolyl group). It is characterized by being a disazo pigment represented by

In the above, substituents on the phenyl group, naphthyl group, anthryl group, pyrenyl group, pyridyl group, chenyl group, furyl group, or carbazolyl group of Ar include norogen, lower alkyl group, lower alkoxy group, and lower dialkylamino group. , nido tetragroup, hydroxyl group, dibenzylamino group, etc.

The present invention will be explained in more detail below. 1. 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.

Examples of conductive supports include plates made of metals such as AA and Ni or their metal oxides, and stainless steel; synthetic paper or plastic films coated with metals such as AA, Pd, and All; polymeric quaternary ammonium salts. Examples include, but are not limited to, paper or cloth impregnated with a conductive substance such as polystyrene sulfonate.

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
sTe, ASz SeHSe-Bi gold alloy 5e-8b
Examples include alloys, but of course the material is not limited to these, and any material that has been conventionally employed as a photoconductive layer of selenium-based electrophotographic photoreceptors can be used. The thickness of this photoconductive layer is preferably 100 μm or less, 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.
It is configured. Examples of the insulating resin here include:
Examples include epoxy resins, acrylic resins, polyimide resins, polyamide resins, phthalate resins, and polyester resins, among which the use of polyester resins and butylene resins provides particularly good results.

Moreover, it is also possible to use two or more kinds 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.

Ar in the general formula H, CO ■ 0,N (8) + OCt Hs H,C H,C \ CI(.

H,C0 0CH.

OCH.

HsCo "C Snow ■3 All of these disazo pigments are known substances, for example, %
It can be easily synthesized and obtained from the site described in Japanese Patent No. 56-94360.

The dispersion amount of the disazo pigment in the insulating resin is appropriately 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% by weight, the resulting photoreceptor will have an increased residual potential, while if it is more than 50% by weight, the adhesion of the intermediate layer itself will decrease. 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 two components (insulating resin and disazo pigment), appropriate additives are added to this intermediate layer in order to improve and stabilize various properties of the intermediate layer or photoreceptor. Good too.

K, who actually makes the photoreceptor according to the present invention, prepares an intermediate layer forming liquid by dispersing the above-mentioned disazo pigment in an insulating resin solution, coats it on a conductive support by a known method, and dries it. After forming an intermediate layer, selenium, a selenium alloy, or a selenium compound may be formed as a photoconductive layer on this intermediate layer by a conventional method such as a vapor deposition method or a sputtering method. Note that tetrahydrofuran is used as the solvent for preparing the intermediate layer forming liquid.

Dimethylformamide, methyl ethyl ketone.

Examples include methylcerenruzo, benzene, toluene, and xylene.

The electrophotographic photoreceptor of the present invention thus produced can fully achieve the intended purpose.

Next, examples and comparative examples will be shown.

Example 1 Buchi 2-ru resin (manufactured by Union Car-Do Co., Ltd.)

4 parts by weight of XYHL) were dissolved in 11 parts by weight of Nato2H2F2F in a glass pot, and then compound A1 was dissolved therein.
1 part by weight of disazo pigment No. 9 and stainless steel I-
and milled for 72 hours. 34 parts by weight of tetrahydrofuran was added to the obtained dispersion to prepare an intermediate layer forming liquid. Next, apply this liquid to stainless steel (8U83
04) to a dry thickness of approximately 1 μm, and dried at 100°C for 1 hour to form an intermediate layer. Further, selenium was vacuum-deposited on top of the intermediate layer (to a thickness of approximately 60 μm). An electrophotographic photoreceptor (Product 1 of the present invention) was prepared by forming a photoconductive layer made of amorphous selenium.

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 of 1 part by weight of the butyl 2-yl resin dissolved in 9 parts by weight of tetrahydrone 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. Table -
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 Surface potential when a 5KV corona discharge is applied to the surface of two samples for 20 seconds.

D, D: VO/VMQ value (Vo is the surface potential when dark decayed for 20 seconds).

E: After dark decay, light is irradiated with a tungsten 2 lamp so that the surface illuminance is 20-13ux, and the surface potential is Vo
The amount of exposure required to become beautiful.

vR: 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.
1 part by weight of the disazo pigment of Compound A 19 and the same stainless steel l-
The mixture was 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 applied onto the same support as in Example 1 so that the thickness after drying would be about 3 μm, and dried at 100°C for 1 hour to form an intermediate layer. An electrophotographic photoreceptor (product of the present invention 2) was prepared by vacuum-depositing a SoTo gold alloy of 8% by weight to form a photoconductive layer made of amorphous Se-To with a thickness of about 60 μm. .

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

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

Claims (1)

[Scope of Claims] 1. On a conductive support, an intermediate layer made of fine particles of an organic pigment dispersed in an insulating resin, and a light layer made of selenium, a selenium alloy, or a selenium compound on top of the varnish. In the electrophotographic photoreceptor provided with a conductive layer, the organic pigment has the following general formula (where Ar is a substituted or unsubstituted phenyl group, a naphthyl group, an anthryl group, a pyrenyl group, a gyrydyl group,
Indicates a chenyl group, furyl group or carnozolyl group. ) An electrophotographic photoreceptor characterized by being a disazo pigment represented by: