JPS59127045A - 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 can be 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.

An electrophotographic photoreceptor is known in which an intermediate layer in which inorganic or organic fine particles are dispersed as a dispersoid on a conductive support and a selenium-based photoconductive layer are provided on the intermediate layer. There is. The purpose of the intermediate layer in such an electrophotographic photoreceptor having a layered structure and structure is to improve the adhesion 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 carne as a dispersoid (Japanese Unexamined Patent Publication No. 126339/1982) and those using metals or chalcogen compounds (Japanese Patent Publication No. 1983-126339).
4-36859), and an example of the latter is one using phthalocyanine (Japanese Patent Publication No. 44-12671).
Publication No.). 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, %, and residual potential fluctuate during repeated use. Other intermediate layers that do not fall into the above category include those made of amorphous resin alone without using dispersoids (Japanese Patent Application Laid-Open No. 103742/1983 is known, but the purpose of this intermediate layer is to This is intended for the effect of suppressing crystallization in the photoconductive layer provided above, and the above 2.
It is different from the intermediate layer of species.

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 made of fine particles of an organic pigment 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 the general formula (wherein, , Art is an aromatic ring such as a benzene ring or a naphthalene ring, a hetero ring such as dibenzofuran, or a substituted product thereof, Arc is an aromatic ring such as a benzene ring or a 7talene ring, or a substituted product thereof, R
o represents hydrogen, a lower alkyl group, a phenyl group, or a substituted product thereof; R8 represents a lower alkyl group, a carmexyl 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 Examples include a carmecycl group, a sulfonic acid group, or a salt thereof. As a substituent on the aromatic ring of Ar4, Ar
In addition to the substituents in 1, examples include an acylamino group and the like. Furthermore, as a substituent for the phenyl group of melon, [hajigen] is mentioned.

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 the conductive support include A4. Plate made of metal or metal oxide such as Nt and stainless steel; A11g
Synthetic paper coated with metal such as P da Au,
Insulating sheets such as plastic films; paper or cloth impregnated with conductive substances such as polymeric quaternary ammonium salts and/or styrene 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 resins, acrylic resins, polyimides, polyamides, butyral resins, and polyesters, among which polyesters and butyral resins 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.

Disazo pigments in which A is A1-26 or more are prepared according to a known method, for example, in JP-A-56-1999.
It can be easily obtained according to the method described in No. 86143.

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 in order to improve and stabilize various properties.

The photoconductive layer is composed of selenium, a selenium alloy, or a selenium compound. Selenium alloy or selenium compound [SeT]
*, Agl Sea, 5s-B1 alloy-5s-8b alloy, and the like. The thickness of the photoconductive layer is suitably 100 microns or less, preferably 10 to 70 microns.

K for making the photoreceptor of the present invention is to apply an insulating resin solution in which the disazo pigment is dispersed on a conductive support and dry it to form an intermediate layer, and then deposit selenium, a selenium alloy, or a selenium compound thereon. A photoconductive layer may be formed.

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

Example 1 Butyral resin (XYHI manufactured by Union Car/Nido Co., Ltd.
) 4 parts by weight of tetrahydro7ran11 in a glass pot.
Then, 1 part by weight of disazo pigment of compound 48 and stainless steel A/I-ru were added thereto,
Milled for 72 hours. Thirty-four parts by weight of tetrahydrofuric acid 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 (5O8304) so that the thickness after drying was 1 μm.
An electrophotographic photoreceptor was prepared by drying at .degree. C. for 1 hour to form an intermediate layer, and then vacuum-depositing selenium thereon to form a photoconductive layer of amorphous selenium having a thickness of 60 .mu.m.

For comparison, the butyral 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) vM: Surface pattern position when a 5KV corona discharge is applied to the sample surface for 20 seconds.

DD: Value of VO/vM (Vo is the surface potential when dark decayed for 20 seconds).

E ring = After dark decay, light is irradiated with a tungsten lamp so that the surface illuminance is 2013ux Ic Table 1 WI'II
The amount of exposure required for the L position to become V2O.

Surface potential after vR two-point light irradiation for 20 seconds.

As can be seen from Table 5, 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 Denipon)
9 parts by weight were dissolved in 23 parts by weight of tetrahydrofuric acid in a glass pot, and 1 part by weight of disazo pigment from Compound Shop 8 and cystineless steel 2-ruol from Example 1 were added thereto and milled for 72 hours. Further, 63 parts by weight of tetrahydro 7 run 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 3μ, and dried at 100°C for 1 hour to form an intermediate layer. Vacuum-deposited 5s-Tef gold for weight [thickness 6o, #amorphous S
An electrophotographic photoreceptor was produced by forming a photoconductive layer made of -Te.

For comparison, an electrophotographic photoreceptor was prepared in the same manner except that β-copper phthalocyanine was used in place 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 residual potential of the comparative product increased by about 90 V from the initial residual potential of 20 V to 110 V, whereas no fluctuation in the residual potential was observed in the product of the present invention.

Patent Applicant Ricoh Co., Ltd. - Agent Patent Attorney Tsukimura Procedural Amendment 1981 Patent Application No. 2306 2 Name of Invention Electrophotographic Photoreceptor 3 Relationship with the Amendment Person Case Patent Applicant Tokyo Metropolitan Government Ricoh Co., Ltd. 1-3-6 Nakamagome, Ota-ku (674) - Representative Takeshi Oue 4, Agent 5 Column for "Detailed description of the invention" in the specification to be amended Contents of the amendment ( 1) On page 6, lines 2 and 10, "...halogen" is corrected to "...for example, halogen."

that's all

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 the general formula (where X is an aromatic ring such as a benzene ring or a naphthalene ring,
A'l is a heterocyclic ring such as an indole ring, a cal/cyl ring, a pencyfudine ring, or a substituent of isoit et al. A'l is an aromatic ring such as a benzene ring or a naphthalene ring, Heterocycle or a substitute thereof, AT! &1 benzene ring,
Aromatic rings such as naphthalene rings or substituted products thereof, R3
is hydrogen, a lower alkyl group, a phenyl group or a substituted product thereof,
R, kt (lower alkyl group), vd (xyl group) or (1) its ester); ] An electrophotographic photoreceptor characterized by being a disazo pigment represented by the following.