JPH0369961A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To form a uniform coating film and the enhance sensitivity and to reduce deterioration of potential due to repeated uses by laminating an electric charge transfer layer containing a polyarylate resin and a charge generating layer containing a prepolymer of diallyl phthalate both as binder resins in this order on a conductive substrate. CONSTITUTION:A metallic material, such as copper, a aluminum, or nickel, or a plastic sheet coated with a metal is used as the conductive substrate 1. The charge transfer layer 2 has a polyarylate resin 5 as the binder resin, the charge generating layer 3 has the prepolymer 6 of the diallyl phthalate as the binder resin, and both layers 2, 3 are laminated in this order on the conductive substrate 1. The resin 5 is low in solvent dissolution speed, and the prepolymer 6 is high in compatibility with the resin 5, thus permitting sensitivity to be enhanced and deterioration of potential to be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an electrophotographic photoreceptor, and particularly to a positively charged photoreceptor having excellent sensitivity and reliability.

[Conventional technology]

Conventionally, photoconductive layers used in electrophotographic photoreceptors include inorganic photoconductive substances such as selenium in a vacuum source, and inorganic photoconductive substances such as zinc oxide or cadmium sulfide in a resin binder. Examples include those in which an organic photoconductive substance such as PVK, a phthalocyanine compound, or a bisazo compound is dispersed in a binder resin, and those in which an organic photoconductive substance such as PVK, a phthalocyanine compound, or a bisazo compound is dispersed in a binder resin, and those in which the organic photoconductive substance is vacuum-deposited.

The functions of an electrophotographic photoreceptor include the function of receiving light and generating charges, and the function of receiving light and transporting charges. Conventional electrophotographic photoreceptors include single-layer photoreceptors, which have the above functions in the same layer, and laminated photoreceptors, which have these functions separated into each layer.The latter type has a practical sensitivity. Are better. However, as copying machines and the like become faster, electrophotographic photoreceptors with higher sensitivity are required.

For example, the Carlson method is applied to image formation by electrophotography using this rod photoreceptor.

The electrophotographic process using this method involves charging a photoreceptor in a dark place by corona discharge, forming an electrostatic latent image of original characters or pictures by exposing the charged photoreceptor surface to light, and This is done by developing a latent image with toner, transferring the developed toner image to a support such as paper, and fixing it. After the toner transfer, the photoreceptor is charged, and the remaining toner is removed. .

In recent years, electrophotographic photoreceptors using organic photoconductive materials have been proposed due to their advantages such as flexibility, thermal stability, and film-forming properties. For example, Bo II-N-vinylcarbazole and 2.
There are photoreceptors made of 4,7-trinitrofluoren-9-one, NA particles whose main ingredients are organic pigments, and photoreceptors whose main ingredients are eutectic complexes made of dyes and resins.

Most electrophotographic photoreceptors using organic photoconductive materials are formed by dissolving a charge-transporting substance and a charge-generating substance together with a film-forming resin and applying the resulting solution using an appropriate coating method.

Such binder resins, for the charge transport layer, polymethyl methacrylate, polysulfone.

Polyester, polyarylate, polycarbonate, etc. are used, and in the case of the charge generation layer, polyester, polyester
Ihibinyl salts, polyvinyl acetate, pea-vinyl acetate copolymers, epoxy, polyether sulfone, polycarbonate, etc. are used.

[Problem to be solved by the invention]

However, in positively charging type photoreceptors in which a charge generation layer is formed on a charge transport layer, the electrostatic solution for the charge generation layer is rich in solvent, so when the charge generation layer is applied, the binder resin in the charge transport layer is dissolved and charges are generated. There have been problems in that the transport layer may be damaged, and depending on the combination of binder resins in the charge transport layer and charge generation layer, coating properties may be poor and the charge generation substance may aggregate. As a result, Hikaru J! ! [, image quality deteriorated, and repeated potential drops were large.

The present invention has been made in view of the above points, and its object is to use a binder resin that has a low dissolution rate in a solvent in the charge transport layer, and to use a binder resin that is highly compatible with this binder resin in the charge generation layer. The object of the present invention is to provide a positively charged photoreceptor with excellent characteristics.

[Means to solve the problem]

The above-mentioned object is achieved by the present invention, which provides a conductive substrate 1.

A charge transport layer 2 and a charge generating layer M3. An electrophotographic photoreceptor comprising: a charge transport layer having a polyarylate resin 5 as a binder resin; a charge generating layer having a diallyl phthalate prepolymer 6 as a binder resin; This is achieved by laminating the charge generation layer on the conductive substrate in this order.

The conductive substrate used in the invention is steel.

Metal materials such as aluminum, nium, nickel, indium, and gold, and plasti-tuff sheets coated with the metals mentioned above can be used. These are preferably used mainly in a cylindrical shape and have sufficient strength for handling.

The charge transport layer is made of polyarylate resin as a binder resin,
! E-carrying substances include derivatives such as pyrazoline, triphenylmethane, styryl, oxydiazole, and hydrazone as solvents. ! It is preferably formed by drying a cloth on a conductive substrate and having a film thickness of 10 to 25 pm. The ratio of the binder resin to the charge transport material is preferably 60 parts by weight to 250 parts by weight of the charge transport material IM to 100 parts by weight of the binder resin. As the solvent, chloroform, chlorobenzene, dichloromethane, dichloroethane, etc. are used.

The charge generation layer contains sialophthalate as a binder resin.
For 100 parts by weight of Revolimer, 50 to 450 parts by weight of a bisazo compound as a charge generating substance is well dispersed with a sand mill, ultrasonic wave, or homogenizer with a solvent such as methyl ethyl ketone, and the dry thickness is 0.
Apply to a 2-2μ thick layer.

[Effect]

The polyarylate resin of the charge transport layer has a slow dissolution rate in a solvent. The diallyl phthalate prepolymer of the charge generation layer is highly compatible with the polyarylate resin.

〔Example〕

Next, embodiments of the present invention will be described based on the drawings.

FIG. 1 is a schematic cross-sectional view showing a positively charged photoreceptor according to an embodiment of the present invention, in which a charge transport layer 2, a VL charge generation layer, and a protection layer 7ii4 are sequentially laminated on a conductive substrate.

(Example 1) As a charge transport substance, 10 parts of P-diethyl amylbenzaldehyde-diphenylhydrazone (ABPH),
A coating liquid was prepared by dissolving 10 parts by weight of polyarylate resin (trade name: U Polymer P-5001:5-manufactured by Nichika) as a binder resin in 1 part by weight of dichloromethane, and a charge transport layer was formed on an aluminum cylinder. . Then on top of that
153t i' parts of a bisazo compound represented by the formula (I) were used as a charge generating substance, and 10ML parts of a diallyl phthalate prepolymer (trade name: DAP NI, manufactured by Osaka W:R) were used as a binder resin.

A biolayer was formed. Further, a protective layer was formed thereon to prepare a photoreceptor.

A photosensitive layer was also formed on a polyethylene terephthalate film on which aluminum had been vapor-deposited, with the same layer structure as above, to produce a sheet-like photoreceptor.

(Example 2) A photoreceptor and a sheet-like photoreceptor were produced in the same manner as in Example 1 except that the charge transport material in Example 1 was changed to a hydrazone compound represented by formula (II).

(Comparative Example 1) A photoconductor and a sheet were prepared in the same manner as in Example 1, except that the charge transport layer binder resin in Example 1 was changed to polymethyl methacrylate (reagent name: Methyl methacrylate (polymer): manufactured by Kasei Kogyo, Tokyo). A photoreceptor was created.

(Comparative Example 2) A photoreceptor and a sheet-like photoreceptor were prepared in the same manner as in Example 1, except that the charge transport layer binder resin in Example 1 was replaced with a polycarbonate resin (trade name: Panrai, L-1225, manufactured by Jyojinka Co., Ltd.). Created.

(Comparative Example 3) The charge generation layer binder resin of Example 1 was replaced with polyester resin (
A photoreceptor and a sheet-like photoreceptor were produced in the same manner as in Example 1, except that the product name was Vylon 200 (trade name: Toyobo).

(Comparative Example 4) The charge generation layer binder resin of Example 2 was replaced with polyester resin (
A photoreceptor and a sheet-like photoreceptor were produced in the same manner as in Example 1, except that the product name was Vylon 200 (trade name: Toyobo).

(Comparative Example 5) A photoreceptor and a sheet-like photoreceptor were prepared in the same manner as in Example 1, except that the charge generation layer binder resin in Example 1 was replaced with a polycarbonate resin (trade name: Panrai L-1225, manufactured by Jyojinka). did.

(Comparative Example 6) A photoreceptor and a sheet-like photoreceptor were prepared in the same manner as in Example 1, except that the charge generation layer binder resin in Example 2 was replaced with a polycarbonate resin (trade name Panlite L-1225: Teijinka tB). did.

The electrophotographic properties of the photoreceptor obtained in this way were evaluated by exposure with a halogen lamp and dry toner development.

Toner transfer to plain paper, cleaning air using a rubber blade and static elimination I! The potential was measured by attaching it to an electrophotographic copying machine with an optical process. At this time, the dark potential (V
o), light area potential (VL), 'j6 and 3 alternately.
The change in Vo (ΔVo) after 00 cycles was evaluated as a repeated potential drop.

In addition, Shido Kou has introduced Kawaguchi Electric's electrostatic recording paper testing device "5P-4".
After corona-charging the sheet-like photoreceptor at 6 kV using 28J, the surface potential was measured, followed by irradiation with white light at an illuminance of 2 lux, and half-exposure t EX (lux・Seconds) were evaluated.

The results are shown in Table 1.

Table 1: Repeated surface potential change and half-attenuation exposure amount As is clear from Table 1, Examples 1 to 2 have a better appearance than Comparative Examples 1 to 6, and the repeated potential decrease and half-attenuation exposure amount The photoreceptor properties of the photoreceptor are also excellent, and the superiority of the combination of this binder resin is clear.

〔Effect of the invention〕

According to the invention, there is provided an electrically conductive substrate and a charge transport layer.

An electrophotographic photoreceptor comprising a charge generation layer, and!
The charge transport layer has a polyarylate resin as a binder resin, the charge generation layer has a diallyl phthalate prepolymer as a binder resin, and the charge transport layer and the charge generation layer are laminated in this order on the conductive substrate. Therefore, the charge transport layer containing the polyarylate resin is not damaged by the bath agent during coating of the charge generation layer and is stable, and the charge generation layer also has a binder resin that is highly compatible with that of the charge transport layer. Therefore, a coating film can be formed uniformly, and an electrophotographic photoreceptor with high sensitivity, small repeated potential drop, and excellent characteristics can be obtained.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view showing a photoreceptor according to an embodiment of the invention.

Claims (1)

[Claims] 1) An electrophotographic photoreceptor having a conductive substrate, a charge transport layer, and a charge generation layer, the charge transport layer having a polyarylate resin as a binder resin, and the charge generation layer having a binder resin. having a prepolymer of diallyl phthalate as
An electrophotographic photoreceptor characterized in that a charge transport layer and a charge generation layer are laminated in this order on a conductive substrate.