JPH01102577A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To provide a sharp copied image without having abnormal images and scumming even after repetitive uses by using a specific base body which contains glass fibers and electrical conducting agent in a resol type phenolic resin as a nonmetallic cylindrical base body and using a vapor deposited aluminum layer having a specific thickness for a conductive layer. CONSTITUTION:The resol type phenolic resin is used as the material of the nonmetallic cylindrical base body and the glass fibers are added as a reinforcing material to the resin in order to enhance the strength. The electrical conducting agent is added to the resin in such a manner that the surface resistance attains 1X10<5>-1X10<11>OMEGA. The vapor deposited aluminum layer having 500-1,500Angstrom film thickness is provided on this base body. The electrophotographic sensitive body which provides the sharp copied image without having scumming even after the repetitive uses is thereby obtd.

Description

[Detailed description of the invention] 〔Technical field〕 The present invention relates to improvements in electrophotographic photoreceptors.

[Prior art]

In recent years, organic photoreceptors have become popular as photoreceptors for electrophotography. The first reason is.

Unlike inorganic photoreceptors, organic photoreceptors exhibit high sensitivity even in the wavelength range of semiconductor lasers, and also have good sensitivity in the general visible light range.

The second reason is that inorganic photoreceptors require a photosensitive layer on the substrate using methods such as vacuum evaporation or glow discharge, which increases equipment costs and requires harsh conditions such as high heat and high vacuum. In order to adopt this method, it is necessary to use a material with excellent heat resistance and volatility resistance as a support, which increases support management costs. Since the conditions are not severe, the cost of illumination is low.

By the way, as a substrate for an inorganic photoreceptor and an organic photoreceptor,
metals such as aluminum, steam, copper, nickel, paper,
Non-metals such as plastic are used, but the cylindrical base is easy to ground.

Currently, aluminum is used as the base material from the viewpoint of dimensional stability.

However, aluminum has the drawbacks of high logistics costs, cutting and surface polishing costs, and poor workability.

To improve this point, we have reduced the price and weight.

It has been previously proposed to use resins such as plastics molded into cylindrical shapes, which have excellent processability, as the substrate for photoreceptors, but with repeated use, background stains become noticeable, and the quality of the resulting copied images deteriorates. The problem was that it became unclear.

For example, a photoreceptor drum made by injection molding of thermoplastic resin or thermosetting resin and having a conductive surface treated (Japanese Unexamined Patent Publication No.
5-124153, JP-A-55-124152) Because a so-called parting line appears on the drum surface,
There is a problem in that abnormal images are generated, and in extrusion molded products, fillers and the like appear on the surface, making the surface of the photoreceptor brittle, resulting in abnormal images.

In addition, a method using a phenolic resin composition containing carbon powder as a base has been proposed (Japanese Patent Application Laid-open No.
(No. 9-86059, JP-A-58-63945, JP-A-58-30764) All of these have weak mechanical strength and have the disadvantage of causing abnormal images and scumming when used repeatedly.

〔the purpose〕

SUMMARY OF THE INVENTION An object of the present invention is to provide an electrophotographic photoreceptor that can produce clear copied images without abnormal images or background smudges even after repeated use, and is extremely easy to manufacture.

〔composition〕

According to the present invention, in an electrophotographic photoreceptor in which a conductive layer and a photosensitive layer are sequentially provided on a nonmetallic cylindrical substrate, the nonmetallic cylindrical substrate contains glass fibers and a conductive agent in a resol type phenolic resin. The surface resistance is I x 105Ω
There is provided an electrophotographic photoreceptor characterized in that the substrate has an I x 10 11 Ω and the conductive layer is an aluminum vapor-deposited layer having a thickness of 500 to 1500 Ω.

In the present invention, a resol type phenolic resin is used as the material for the nonmetallic cylindrical substrate.

A resol type phenolic resin is a thermosetting resin obtained by heating and condensing phenol and formaldehyde in the presence of an alkaline catalyst.

Unlike novolac type phenolic resins, this resol type phenolic resin does not generate by-products, especially ammonia, and has excellent hardness.

When this product is extruded, a cylindrical drum having excellent dimensional accuracy with a circularity of 200 μm or less and a surface roughness of 2 μmRz or less can be obtained.

In the present invention, glass fiber is added as a reinforcing agent in order to further increase the strength of the nonmetallic cylindrical substrate mainly composed of resol type phenolic resin.

As for the shape of the glass fiber, it is necessary to use a diameter of 1 to 20 μm, preferably 10 to 15 μm, and a length of 100 to 500 μm, preferably IOO to 200 μm, and the amount used is based on the total weight of the resin composition. 5-30% by weight, preferably 20-30% by weight.

If the diameter of the glass fiber is 1 μm, the strength will be insufficient.
Moreover, if it exceeds 20 μm, the surface properties and workability deteriorate, which is not preferable.

In addition, if the amount of glass fiber used is less than 5% by weight, the reinforcing effect will not be sufficiently expressed, and if it exceeds 30% by weight, the smoothness of the surface will decrease, further damaging the processing machine and causing the processing machine to become unstable. In addition, the resol-type phenolic resin base of the present invention has a surface resistance of l in order to eliminate disturbances caused by static electricity, such as to prevent dust from adhering and to improve the grounding function of the conductive layer.
X 105Ω - I X 10”Ω, preferably 105Ω
A conductive agent is added so that the resistance is ~10''Ω.

As the conductive agent, any conventionally known conductive agent can be used. For example, one type or a combination of two or more of metal powders such as carbon black, graphite, gold, silver, copper, and aluminum are used, and the amount used is as described above. It is selected within a range that provides a surface resistance value, and is usually in the range of 5 to 25%.

The resol-type phenol resin used as a support in the present invention may optionally contain calcium carbonate, talc, aluminum hydroxide, magnesium hydroxide, fillers, etc.
Diatomaceous earth, silica, clay, kaolin, titanium oxide, carbon black, metal powder.

By adding graphite, glass fiber, potassium titanate, asbestos, wood flour, synthetic fibers, pulp, etc., it is possible to improve the softness point, dimensional accuracy, and conductivity imparting effect.

The electrophotographic photoreceptor of the present invention is characterized by using the above-mentioned specific resol type phenolic resin as a non-metallic cylindrical substrate, but if a photosensitive layer is further provided directly on the substrate, carbon free carriers is injected into the photosensitive layer, charging no longer occurs, and the sensitivity decreases due to the low reflectance of the substrate.

Film thickness SOO~1500, preferably 600-1000
It is necessary to provide a layer of aluminum vapor deposition. The aluminum evaporated layer may be an aluminum oxide film whose surface is oxidized and acts as a barrier to free carriers.

If the thickness of the aluminum vapor deposition layer is less than 500 mm, the effect of preventing injection of free carriers will be insufficient.

The reflectance of aluminum decreases, the sensitivity becomes slower, and 150
If the number exceeds 0, the object becomes brittle and the intended purpose of the present invention cannot be achieved.

The photosensitive layer in the present invention may be either a laminated type photosensitive layer having a charge generation layer and a charge transfer layer or a single layer type photosensitive layer, but it is preferable to use a laminated type photosensitive layer.

The charge generation layer is formed from a charge generation substance and a resin binder.

As the resin binder, polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer,
Polyvinyl acetate, polyvinylidene chloride, polyacrylate resin, phenoxy resin, polycarbonate, cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral, polyvinyl formal, polyvinyltoluene, poly-N-vinylcarbazole, acrylic resin, silicone resin, epoxy resin, melamine Examples include thermoplastic or thermosetting resins such as resins, urethane resins, phenol resins, and alkyd resins.

Examples of the charge generating substance include CI Pigment Blue 25 [Color Index (CI) 21180],
CI Pigment Red 41 (CI 21200),
C.I. Acid Red 52 (CI 45100), C.I. Basic Red 3 (CI 45210), and a phthalocyanine pigment having a porphyrin skeleton,
Azulenium salt pigments, squalic salt pigments, azo pigments with a carbazole skeleton (described in JP-A-53-95033), azo pigments with a stilstilbene skeleton (
(described in JP-A No. 53-138229), azo pigments having a triphenylamine skeleton (described in JP-A-53-1325)
47), azo pigments having a dibenzothiophene skeleton (described in JP-A No. 54-21728), azo pigments having an oxadiazole skeleton (described in JP-A-54-1
2742), azo pigments having a fluorenone skeleton (described in JP-A-54-22834), azo pigments having a bisstilbene skeleton (described in JP-A-54-177)
33), an azo pigment having a distyryloxadiazole skeleton (described in JP-A No. 54-2129), an azo pigment having a distyrylcarbazole skeleton (described in JP-A-54-17734) , a triazo pigment having a carbazole skeleton (JP-A-57-195767).

57-195768), phthalocyanine pigments such as CI Pigment Blue 16 (CI 74100), CI Bat Brown 5 (CI
73410), CI 7303
Organic pigments such as indigo pigments such as 0) and perylene pigments such as Argo Scarlet B (manufactured by Violet) and Indus Thread Scarlet R (manufactured by Bayer) can be used.

The thickness of the charge generation layer is suitably about 0.05-2 .mu.m, preferably 0.1-1 .mu.m.

The charge generation layer can be formed by dissolving or dispersing the binder and charge generation substance described above in a suitable solvent, applying the solution, and drying the solution. As a solvent, benzene, toluene, xylene, methylene chloride, dichloroethane, monochlorobenzene.

Dichlorobenzene, ethyl acetate, butyl acetate, methyl ethyl ketone, dioxane, tetrahydrofuran, cyclohexanone, methyl cellosolve, ethyl cellosolve, etc. can be used alone or in combination.

The charge transfer layer can be formed by dissolving or dispersing a charge transfer substance and a resin binder similar to that used in the charge generation layer in an appropriate solvent, coating the solution on the charge generation layer, and drying the solution. Moreover, a plasticizer, a leveling agent, etc. can also be added if necessary.

Charge transfer substances include poly-N-vinylcarbazole and its derivatives, poly-carbazolylethyl glutamate and its derivatives, pyrene-formaldehyde condensate and its derivatives, polyvinylpyrene, polyvinylphenanthrene, oxazole derivatives, oxadiazole derivatives. , imidazole derivatives, triphenylamine derivatives, 9-(p-diethylaminostyryl)anthracene, 1.1-bis-(4-dibenzylaminophenyl)propane, styrylanthracene, styrylpyrazoline, phenylhydrazones, α-phenylstilbene Examples include electron-donating substances such as derivatives.

As the solvent at this time, tetrahydrofuran, dioxane, toluene, monochlorobenzene, dichloroethane, methylene chloride, etc. can be used.

The appropriate thickness of the charge transfer layer is about 5 to 100 microns.

Further, the single-layer type photosensitive layer is composed of the charge generating substance, the charge transporting substance, and the binder resin.

Furthermore, in the present invention, between the support and the photosensitive layer, polyamide, polyvinyl alcohol, polyvinyl acetal, polyacrylic acid, polyhydroxymethacrylate,
It is also possible to provide an intermediate layer such as an epoxy resin or a white pigment layer consisting of the resin and a white pigment such as titanium chloride, zinc oxide, magnesium oxide, barium sulfate, or lithopone.

〔effect〕

Since the electrophotographic photoreceptor of the present invention has the above configuration,
Since the support has excellent dimensional accuracy and stable photoreceptor characteristics, it provides clear copied images without abnormal images or scumming even after repeated use.

〔Example〕

Next, the present invention will be explained in more detail with reference to Examples.

Example: A resol type phenolic resin composition containing glass fibers with carbon 25 weight, diameter 10 μI, and length 100 μm, outer diameter 80 mm, inner diameter 71 mm, length 34 G+L.
II was molded into a cylindrical shape to form a base. The resistance of this substrate was 10''Ω/mouth. Next, aluminum was deposited on this cylindrical substrate to a thickness of 600 Ω.

A photosensitive layer was then provided in the following manner to produce a photoreceptor of the present invention.

(1! Formation of charge generation layer) 200 g of cyclohexanone The above composition was dispersed, and a mixed solvent of cyclohexanone: methyl ethyl ketone = 1 = 1 was added and let down to obtain a charge generation layer coating solution. This coating solution was spray coated onto the support to form a charge generating layer having a thickness of 0.2 μm.

[Formation of charge transfer layer]

Polycarbonate (Teijinsha Rip, C-1400) 28
0 g silicone oil (manufactured by Shin-Etsu Chemical Co., Ltd., KF-50)
0.5 g of the above ingredients in tetrahydrofuran 1700
Dissolved in g. Next, this solution was spray-coated onto the charge generation layer using a mixed solvent of cyclohexanone and tetrahydrofuran = 1 = 1, and dried at 120°C for 30 minutes.
A charge transfer layer with a thickness of μm was provided.

Next, this photoreceptor was installed in a copying machine FT-4060 (Ricoh Co., Ltd. m> modified to be negatively charged), and its characteristics were investigated. The sensitivity was 1.4 to 1.61 ux-sec and the charging potential was 800 V Moreover, this property hardly changed even after 100,000 copies.

Comparative Example A phenolic resin composition containing 20% by weight of carbon black and 30% by weight of wood flour was heated to an outer diameter of 80 mm and an inner diameter of 71 m.
+a, and was formed into a cylindrical shape with a length of 340+++m to provide a base.

Next, the following polyamide layer forming solution was dip coated onto this substrate and dried at 100° C. for 10 minutes to form a polyamide layer.

[Polyamide layer forming liquid]

Nylon 6/66/610/12
10g methanol 60
g Toluene 30 g Next, the same photosensitive layer as in the example was provided on this polyamide layer to create a photoreceptor as a comparative example.

When the photoreceptor thus obtained was subjected to the same test as in the example, the sensitivity was 1.9-2.01 ux-sec and the charging potential was 800V.

, Also, the charging potential after copying in October is 6 from 800V.
00v, and the residual potential rose to 50v.

Furthermore, the strength of this photoreceptor was low, and 10% of the photoreceptor was damaged when it was mounted, and its brocade was damaged when it was rotated.

Furthermore, when this photoreceptor is exposed to high temperature and high humidity, unevenness occurs on its surface, resulting in abnormal images.Furthermore, expansion of the inner diameter causes a gap between the photoreceptor and the flange, resulting in rotational misalignment, making normal operation impossible.

Patent applicant Rico Co., Ltd.

Claims (1)

[Claims] (1) In an electrophotographic photoreceptor in which a conductive layer and a photosensitive layer are sequentially provided on a nonmetallic cylindrical substrate, the surface resistance of the nonmetallic cylindrical substrate is obtained by containing glass fiber and a conductive agent in a resol type phenolic resin. is 1×10^5Ω~1×10^
1^1Ω substrate, and the conductive layer has a thickness of 500 to 1Ω.
An electrophotographic photoreceptor characterized by having a 500 angstrom aluminum vapor deposited layer.