JPS63133160A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To obtain a high-sensitivity electrophotographic sensitive body even if a phenolic layer dispersed with carbon is used as a conductive base layer by providing an insulating layer on the phenolic resin layer dispersed with carbon and providing a layer dispersed with a pigment on the insulating layer. CONSTITUTION:The insulating layer is provided on the phenolic resin layer dispersed with the carbon and the layer dispersed with the pigment is provided on said insulating layer. The phenolic resin which has <=10<8>OMEGA, more particularly <=10<5>OMEGA electric resistance on the surface is preferable as the phenolic resin dispersed with the carbon. There is no particular limitation as the material to form the insulating layer, for which various org. high-polymer compds. are usable; for example, synthetic high polymers such as PP resin, acrylic resin, polyimide resin and polysilastyrene and natural high polymers such as casein, starch and cellulose or the modified matters thereof are used. Water soluble natural high polymers or the moldified polymers thereof are more preferable above all. The preferred thickness of the insulating layer is usually 0.01-3mu. The good electrophotographic sensitive body is thereby formed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electrophotographic photoreceptor. More specifically, the present invention relates to an electrophotographic photoreceptor comprising a specific conductive support layer.

[Prior Art] Electrophotographic photoreceptors are made of organic compounds such as combinations of various dyes such as phthalocyanine dyes, diazo dyes, and perylene dyes with polyvinylcarbazole, oxadiazole, hydrazone, and pyrazoline. Compared to electrophotographic photoreceptors made of inorganic photoconductive compounds such as cadmium, they have advantages such as non-polluting properties and high productivity, and various combinations of high sensitivity and excellent durability have been proposed.

[Problems to be Solved by the Invention] The organic compound-based electrophotographic photoreceptors described above are excellent, but those that use metals such as aluminum as the conductive support layer must be disposed of by incineration, etc. is difficult. On the other hand, resins made conductive by mixing carbon etc., especially those using phenol resins, have excellent surface conditions and are expected to be used; For reasons unknown, electrophotographic photoreceptors have had the problem of poor performance.

[Means for solving problems]

The inventors of the present invention have conducted extensive studies on methods for solving the above problems, and have completed the present invention.

That is, the present invention is an electrophotographic photoreceptor in which an insulating layer is provided on a phenol resin layer in which carbon is dispersed, and a layer in which a pigment is dispersed is provided on the insulating layer.

The electrophotographic photoreceptor of the present invention may be of a functionally separated type (a multilayer type having at least two layers, a charge generation layer and a charge transfer layer) or a single layer type, but is particularly a functionally separated type, i.e. This method is more effective in the case of a multilayer photoreceptor having at least two layers, a charge generation layer and a charge transfer layer.

In the present invention, various materials can be used as the charge generation layer, and there are no particular limitations, and many pigments known for use in electrophotography can be used. For example, azo pigments such as Sudan Red, Guianpuru, Jenas Green B, quinone pigments such as Algol Yellow, Pyrenequinone, Indanthrene Brilliant, and Violet RRP, quinocyanine pigments, indigo pigments such as Indigo and Thioindigo, and Indian Examples include bishenzimidazur pigments such as Fast Orange, phthalocyanine pigments such as copper phthalocyanine, and quinacridone pigments such as quinacridone. These pigments are used at a relatively high concentration (0.1 to 0.9 weight ratio in the solid substance) in the functionally separated type, and at a relatively low concentration (0.01 to 0.5 weight ratio in the solid substance) in the single layer type. ) and dispersed in an organic binder to form a charge generation layer or photoreceptor. Examples of the organic binder that can be used here include polyester, polyvinyl butyral, polycarbonate, polystyrene, polyvinyl chloride, methyl cellulose, acrylic resin, and organic polysilane.

This charge generation layer is 0901 to 1μ (5 to 50μ for a single layer type) on a support layer made of a phenol resin and an insulating layer, which will be described later.
It is applied to a thickness of .

In the functionally separated type, a charge transfer layer is formed by coating on the charge generation layer. As the charge transfer layer, polycyclic aromatic compounds such as anthracene, pyrene, phenanthrene, indole, carbazole, oxazole, isoxazole,
Nitrogen-containing cyclic compounds such as thiazole, imidazole, pyrazole, oxadiazole, birapurin, and thiazole are dispersed in the above-mentioned organic binder at a relatively high concentration.

In the single layer type, various organic compounds such as triphenylamine, 2,4.6-)linitrofluorenone, dicyanobenzene, triphenylmethane, etc. can also be used in combination with the pigment.

What is important in the present invention is that a phenolic resin in which carbon is dispersed is used as the conductive support layer, an insulating layer is provided on the conductive phenolic resin, and the photosensitive layer is formed thereon.

The phenolic resin in which carbon is dispersed is not particularly limited, and those made by various known methods can be used, but it is preferable that the electrical resistance at least on the surface is 10 8 Ω or less, particularly 10 5 Ω or less. This carbon-dispersed phenolic resin is manufactured by adding 54% or more, preferably 10wt% or more of carbon to a prepolymer such as resol or novolac, and adding reinforcing agents or extenders as necessary, molding the mixture together, and heating and curing the resin. can.

What is important in the present invention is to provide an insulating layer on the phenolic resin, and there are no particular restrictions on the material for forming this insulating layer, and various organic polymer compounds can be used.
For example, synthetic polymers such as polypropylene resin, acrylic resin, methacrylic resin, polyvinyl chloride resin, epoxy resin, polyester resin, acrylic resin, polyurethane resin, polyimide resin, polysilastyrene, casein,
Natural polymers such as starch and cellulose or modified products thereof are used. Among these, water-soluble natural polymers or polymers modified therewith are preferably used. The thickness of this insulating layer is usually preferably 0.01 to 3 .mu.m.

This insulating layer is not essential when a metal such as aluminum is used as a conductive support layer, but when a phenolic resin in which carbon is dispersed is used as a conductive support layer, this layer is necessary to obtain a highly sensitive electrophotographic photoreceptor. is essential, and without it a good electrophotographic photoreceptor cannot be formed.

〔Example] The present invention will be further explained below with reference to Examples.

Example Two layers of Luzol-type phenolic resin dispersed with 2 layers of carbon (wt%) and cured (surface resistivity 4X10'Ωcm)
is used as a substrate, and casein (manufactured by Wako Pure Chemical Industries, Ltd., Reagent 1) is placed on top of it.
Aqueous solution (casein 5wt%, ammonia 1wt%)
) was applied so that the thickness after drying was 0.3μ, and
After drying at 50°C, 1 wt% of τ-type phthalocyanine (manufactured by Toyo Ink Manufacturing ■, "Liophton") and 5 wt% of polyester resin (manufactured by Toyobo ■, "Vylon 200'")
% dispersed in tetrahydrofuran was applied to a dry thickness of 1 μm and dried. After drying, a hydrazone compound represented by the following formula, a solution of the above-mentioned polyester resin and tetrahydrofuran in a weight ratio of 1:1:5, was applied thereon to a thickness of 15 μm and dried.

The photoreceptor thus obtained was evaluated using an Electrostatic Paper Analyzer EPA-8100 (manufactured by Kawaguchi Electric). First, -6 kV corona discharge
After measuring the initial surface potential for 2 seconds, it was left in a dark place for 2 seconds, and then passed through a color glass filter IR-80 (manufactured by Hoya Glass) and exposed to light with an illuminance of 2°lux to measure the half-life exposure. did.

The results are shown in Table 1, where the initial voltage is vo and the half-life exposure is El/
2 (IIIX 5ec).

Example 2.3 In place of casein aqueous solution, hydroxyedyl cellulose aqueous solution (5-t%, Example 2) or Scooch aqueous solution (
The procedure was the same as in Example 1 except that 5 wt % (Example 3) was used. The results are shown in Table-1.

Note that all of these reagents were manufactured by Wako Pure Chemical Industries, Ltd.

Reference Example J A photoreceptor was manufactured using an aluminum plate instead of a phenol resin plate without providing an insulating layer, and the photoreceptor was evaluated. The results are shown in Table-1.

Comparative Example 1 In Example 1, a photoreceptor was manufactured without providing a casein layer and evaluated. The results are shown in Table-1.

Example 4, Comparative Example 2 The same procedures as in Example 1 and Comparative Example 1 were carried out, except that a cured novolac resin (specific resistance 3×10”Ω) was used instead of a cured resol resin. The results are shown in Table-1.

Table 1 [Effects of the Invention] The electrophotographic photoreceptor of the present invention can be used not only in electrophotographic copying machines, but also in a wide range of electrophotographic application fields such as laser printers, CRT printers, and electrophotographic plate-making systems. It is possible and has industrial value.

Claims (1)

[Scope of Claims] 1. An electrophotographic photoreceptor comprising an insulating layer provided on a phenol resin layer in which carbon is dispersed, and a layer in which pigment is dispersed on the insulating layer. 2. Claim 1 in which the insulating layer is a water-soluble polymer
The electrophotographic photoreceptor described in .