JPS61204640A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To ensure adhesion between a conductive substrate and a photoconductive layer without deteriorating photosensitive characteristics, by incorporating in an undercoat layer a material functioning without deteriorating photosensitive characteristics and not impairing an intrinsic adhesive function. CONSTITUTION:An electrophotographic sensitive body has a layer structure formed by laminating the undercoat layer and the photoconductive layer on the conductive substrate in this order. The first component of the undercoat layer is embodied by PVA or polyvinyl methyl ether, and as the second component charge transfer material, ordinary charge transfer materials for use in the photoconductive layer of the ordinary electrophotographic sensitive body are used, and embodied by imidazole, pyrazoline, etc., and their derivs., and both components are used, preferably, in a mixing ratio of 0.01:1-3:1, thus permitting residual potential to be eliminated and acceptance potential characteristics not to be deteriorated at all.

Description

Detailed Description of the Invention [Technical Field of the Invention] The present invention relates to an electrophotographic photoreceptor, and more particularly, to an electrophotographic photoreceptor that improves the adhesion between a conductive support and a photoconductive layer without causing deterioration of photosensitive characteristics. The present invention relates to an electrophotographic photoreceptor having a subbing layer that can be coated.

[Technical background of the invention and its problems] The photoconductive process of an electrophotographic photoreceptor consists of a charge generation process and a charge transport process. It is common to have a structure in which photoconductive layers to be processed are laminated.

There are two types of photoconductive layers, one in which the above two processes are performed using a single material, and another in which the two processes are performed using separate materials. Among these methods, the method in which each process is performed using separate substances has a wider range of materials to choose from for the photoreceptor than the former method, so the electrophotographic properties such as photosensitivity and acceptance potential of the resulting photoreceptor are improved. Furthermore, it has the advantage that it is possible to form a film having excellent film formability and physical properties when manufacturing a photoreceptor.

A specific example of the structure of such a photoconductive layer is one in which a charge-generating layer made of a charge-generating material and a charge-transporting layer made of a charge-transporting material are laminated (laminated type), or a layer in which a charge-generating material and a charge-transporting material are laminated. (Molecule B)
type l).

However, regardless of the structure of conventional electrophotographic photoreceptors, there is a problem in that the adhesion between the conductive support and the photoconductive layer is generally not good. Therefore, when stress such as bending or tension is applied to the photoreceptor, the film peels off, and as a result, electrical stress concentrates on the defective part of the conductive support, causing discharge breakdown and image formation. White spots may appear on the skin.

In order to solve this problem, it is common practice to interpose an intermediate layer, a so-called undercoat layer, between the conductive support and the photoconductive layer, which has the function of adhering the two. and such subbing layer typically includes, for example, casein,
It is made of resin such as polyvinyl alcohol.

However, in electrophotographic photoreceptors having an undercoat layer made of this resin, although the adhesion between the conductive support and the photoconductive layer is improved, on the other hand, the photosensitive characteristics of the photoreceptor itself deteriorate. A new problem arises. Specifically, problems such as an increase in residual potential and a decrease in sensitivity and charge amount occur frequently during repeated charging and exposure.

[Object of the Invention] The present invention solves the conventional problems and provides an 'IL' provided with an undercoat layer capable of reliably adhering a conductive support and a photoconductive layer without causing deterioration of photosensitive properties. The purpose is to provide a child photographic photoreceptor.

[Summary of the Invention] The present inventors added a substance to the undercoat layer that functions not to deteriorate the photosensitive characteristics of the photoreceptor itself and does not impair the adhesive function that the undercoat layer has. In particular, we got the idea that the above object could be achieved, and as a result of various studies based on this idea, we were able to complete the present invention by discovering the desired substance as described below. .

That is, the electrophotographic photoreceptor of the present invention is an electrophotographic photoreceptor having a layer structure in which a conductive support, an undercoat layer, and a photoconductive layer are laminated in this order, and the undercoat layer is ,
It is characterized by being formed from a resin and a charge transport material.

The undercoat layer in the electrophotographic photoreceptor of the present invention is particularly suitable for use in those having the above-described laminated type and dispersed type photoconductive layers.

As the resin that is the first component constituting this undercoat layer, resins that are conventionally well known as undercoat layers can be used, and specifically, polyvinyl alcohol and polyvinyl methyl ether.

Examples include poly-N-vinylimidazole, polyethylene oxide, ethyl cellulose, methyl cellulose, ethylene-acrylic acid copolymer, casein polyamide, polyethylene, polyester, phenol resin, vinyl chloride-vinyl acetate copolymer, and epoxy resin.

On the other hand, the charge transport material which is the second component of the undercoat layer is a charge transport material used in the photoconductive layer of a normal electrophotographic photoreceptor, and is a charge transport material that is compatible with the above resin. Not particularly limited, specifically, imidazole, pyrazoline, thiazole, oxadiazole,
Examples include oxazole, hydrazone, ketazine, azine, carbazole, polyvinylcarbazole, etc., and derivatives thereof, and as charge transport materials, these may be used alone or in combination of two or more.
Note that the charge transport material used in the undercoat layer may be the same as or different from the charge transport material used in the photoconductive layer, which will be described later.

In the undercoat layer of the present invention, the blending amount of the above two components is such that the mixing ratio of the charge transport material and the resin is 0.01:1 to 3:
1 is preferable. If the amount of the charge transport material is too small, the effect of improving photosensitivity will hardly be exhibited. On the other hand, if it is too large, it will precipitate as crystals after the undercoat layer is formed. It becomes impossible to use. Particularly preferably, the ratio between the two is 0.1:1 to 1:1.

The conductive support constituting the electrophotographic photoreceptor of the present invention is not particularly limited as long as it has conductivity and can serve as a support member. Specific examples include sheet-shaped aluminum (text A), copper (Cu), and nickel (
old), silver (Ag), palladium (Pd), indium (
In), lead (PB), gold (Au), platinum (PT), stainless steel, etc.; A pattern on the insulating sheet, Cu, Ni, A
Examples include substrates coated with Pd, In, Pb, Au, Pt, etc.

In the electrophotographic photoreceptor of the present invention, the photoconductive layer is composed of a charge generating material and a charge transporting material. Examples of charge generating materials include selenium and selenium alloys; Cd
S, CdSe, Cd55e, ZnO and ZnS
inorganic photoconductors such as; phthalocyanine pigments such as metal phthalocyanines and metal-free phthalocyanines; azo dyes such as monoazo and disazo dyes; perylene pigments such as perylene anhydride and perylene imide; indigoid dyes; quinacridone pigments; anthraquinones cyanine dyes; xanthine dyes; charge transfer complexes consisting of electron-donating substances such as poly-N-vinylcarbazole and trinitrofluorenone; pyrylium salt Examples include eutectic complexes consisting of dyes and polycarbonate resins.

On the other hand, the charge transport material is not particularly limited as long as it is transparent to visible light and has charge transport ability, and in addition to those listed above, triphenylamine derivatives, fluorenone derivatives, Dibenzothiophene derivative.

Examples include thioxanthone derivatives.

The electrophotographic photoreceptor of the present invention is manufactured as follows.

That is, first, an undercoat layer is formed on the conductive support. Specifically, a mixture of the above resin and charge transport material at a predetermined mixing ratio is dissolved in an appropriate solvent,
This solution can be coated and dried on a conductive support using a conventional method. The thickness of the undercoat layer is preferably o, oos to 5-5. If this thickness is too thin, charging characteristics There is no improvement effect, and on the contrary, even if the thickness is increased without any limit, the effect reaches saturation and there is no advantage in terms of process.

Thereafter, a photoconductive layer is formed on this undercoat layer. Although the photoconductive layer may be either a laminated type or a dispersed type as described above, a laminated type will be described here as an example. Although the order in which the charge generation layer and charge transport layer constituting the photoconductive layer are stacked is not particularly limited, from the viewpoint of increasing the physical strength of the photoreceptor, it is preferable to stack the charge generation layer and charge transport layer in this order. A laminated structure is preferable.

The method for forming the charge generation layer varies depending on the type of charge generation material used, but the charge generation material listed above may be used as is, or it may be formed using a resin binder such as phenoxy resin, polyester resin, or polycarbonate resin. It can be formed by applying a dispersed material, or by applying a vacuum evaporation method, a sputtering method, a glow discharge method, or the like. On the other hand, for the charge transport layer, the above charge transport material is used as an organic polymer compound 1, such as polystyrene, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, polyacetal, phenol resin, epoxy resin, alkyd resin. For example, it can be formed by coating and drying a mixture dispersed in, for example, a conventional method.

The thickness of the photocharge-generating material layer and the charge-transporting material layer formed on the undercoat layer is determined as appropriate depending on the charging characteristics required for the electrophotographic photoreceptor. , and the thickness of the charge transport material layer is preferably about 5 to 100 μm.

By having the above-described layer structure, the photoreceptor of the present invention has good adhesion between the conductive support and the photoconductive layer, and does not peel off due to stress such as bending. Since a charge transport material is added to the undercoat layer, there is no residual potential and the charging characteristics will not deteriorate.
This is thought to be due to the fact that charge injection is blocked at the bonding interface between the conductive support and the undercoat layer.

[Examples of the Invention] Example 1 A mylar film on which aluminum was vapor-deposited was used as a conductive support, and 30% by weight of a hydrazone compound represented by the following formula (I) was coated with a polyester resin on the aluminum-deposited surface of the film. A solution containing 60% by weight of Slen Brilliant Orange dispersed in a phenoxy resin was applied as a charge generating layer on the undercoat layer to a thickness of 0.4 mm. A solution of 50% by weight of the hydrazone compound of the formula (I) dispersed in a polycarbonate resin is coated on the layer to a thickness of 15 as a charge transport layer. - It was dried to complete the electrophotographic photoreceptor of the present invention.

The charging and exposure characteristics of the photoreceptor thus obtained were measured using Paper Analyzer 5P-428 manufactured by Kawaguchi Denki ■, and the initial values and the values after repeated use 1500 times are shown in the table.

Furthermore, when an actual copying experiment was carried out using this photoreceptor using an experimental copying apparatus, even after 4,000 copies, L-quality images without white spots, which were the same as the initial image, were obtained.

Example 2 The undercoat layer was prepared by coating and drying a solution in which 5 weights of a pyrazoline compound represented by the following formula (II) was dispersed in a polyvinyl alcohol resin to a thickness of 0.5 JJj. A photoreceptor was manufactured in the same manner as in the above example, and its charging and exposure characteristics were investigated.

The results are shown in the table. As a result of copying experiments, good images with the same quality as the initial image were obtained even after 2000 copies.

In the above Example 1, two photoreceptors were manufactured, one without the hydrazone compound added to the undercoat layer (Comparative Example L) and one without the undercoat layer (Comparative Example 2). The charging exposure characteristics were measured in the same manner as above.The results are shown in the table.The results of the copying experiment showed that in Comparative Examples 1 and 2, the photoconductive layer peeled off from the Mylar film after 1000 copies.

As is clear from the above description, the electrophotographic photoreceptor of the present invention has good adhesion between the conductive support and the photoconductive layer, and does not peel off even during repeated copying. Since a charge transporting material was added to the drawing layer, it was confirmed that it had excellent charging exposure characteristics and photosensitivity, and in particular, it had no residual potential, so it was extremely reliable for repeated use.

Therefore, its industrial value is great.

Claims (1)

[Claims] 1. An electrophotographic photoreceptor having a layer structure in which a conductive support, an undercoat layer, and a photoconductive layer are laminated in this order, the undercoat layer comprising a resin and a photoconductive layer. An electrophotographic photoreceptor characterized in that it is formed from a charge transporting material. 2. The electrophotographic photoreceptor according to claim 1, wherein the undercoat layer has a mixing ratio of the charge transport material and the resin in a weight ratio of 0.01:1 to 3:1. 3. The electrophotographic photoreceptor according to claim 1, wherein the undercoat layer has a thickness of 0.005 to 5 μm.