JPH08320584A - Electrophotographic photoreceptor - Google Patents

Abstract

PURPOSE: To improve the electric charge retentivity of τ-type metal-free phthalocyanine and to regulate sensitivity by incorporating the τ-type metal-free phthalocyanine and specified perylene-3,4,9,10-tetracarboxylic acid-bis(phenethylimide) into an electric charge generating layer. CONSTITUTION: τ-type metal-free phthalocyanine is used as an electric charge generating material forming an electric charge generating layer and perylene-3,4,9,10-tetracarboxylic acid-bis(phenethylimide) represented by the formula is further added. When this perylene-3,4,9,10-tetracarboxylic acid-bis(phenethylimide) is incorporated into the electric charge generating layer, it is used by 0.01-4 equiv., preferably 0.2-2 equiv. per 1 equiv. of the metal-free phthalocyanine. The electric charge generating layer is formed with a material prepd. by dispersing the electric charge generating material in a bonding resin.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photoconductor for electrophotography which is used when an image is formed by an electrophotographic process such as a copying machine, a printer or a facsimile.

[0002]

2. Description of the Related Art Inorganic materials such as selenium, cadmium oxide, zinc oxide and amorphous silicon have been conventionally used as photoconductive materials for electrophotographic photoreceptors. However, in recent years, a material using an organic material which is advantageous in terms of pollution and manufacturing cost has been put into practical use. In particular, a laminated organic photoreceptor having a charge generation layer and a charge transport layer, whose functions are separated, has become the mainstream. When τ-type metal-free phthalocyanine is used as the charge generation material for forming this charge generation layer, the charge is easily injected from above the conductive support because the ionization potential is small (5.03 eV), It causes a decrease in retention rate. If the charge retention rate of the charge generation material is low, it affects the image formed in the electrophotographic process,
In addition, problems such as a decrease in electrostatic potential occur in the printing durability test.
There is also a need to adjust the sensitivity to improve the resolution in the image.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an electrophotographic photosensitive member capable of improving the charge retention rate of the charge generating material τ type metal-free phthalocyanine and adjusting the sensitivity.

[0004]

The present invention uses a τ-type metal-free phthalocyanine as a charge generating material for forming a charge generating layer, and further uses a perylene-type compound represented by the following general formula 1.
The addition of 3,4,9,10-tetracarboxylic acid-bis (phenethylimide) achieves the above-mentioned object.

Embedded image

When perylene-3,4,9,10-tetracarboxylic acid-bis (phenethylimide) is contained in the charge generation layer, it is added to the τ type metal-free phthalocyanine in an amount of 0.
A range of 01 to 4 equivalents, preferably 0.2 to 2 equivalents is desirable. When the amount is less than 0.2 equivalent, the charge retention rate decreases, and the sensitivity adjusting function is not sufficiently fulfilled. When the amount is more than 2 equivalents, the material itself does not have sensitivity, so that the sensitivity is remarkably lowered.

As the conductive support located in the lowermost layer of the electrophotographic photosensitive member of the present invention, a material having sufficient conductivity is suitable. For example, metals such as aluminum, titanium, copper, nickel, zinc and chromium, or alloys thereof are used. In addition, metal such as aluminum, copper, gold, silver, platinum, palladium or metal oxide such as tin oxide or indium oxide is vapor-deposited on plastic or glass, or carbon black or metal powder is dispersed in a binder resin. It is possible to use a material that has been subjected to a conductive treatment by applying it.

Further, between the conductive support and the charge generation layer,
An intermediate layer may be provided. This intermediate layer not only prevents the injection of charges from the conductive support to the photosensitive layer, but also serves to adhere the photosensitive layer to the conductive support.

The intermediate layer is made of polyamide, polyvinyl alcohol, polyurethane, polyacrylic acid, polyethylene,
A known resin such as an epoxy resin can be used. Further, it may be formed by dispersing conductive fine particles such as metal powder in these resins, or an anodized film such as alumite. The thickness of these intermediate layers is 0.01 to 1
0 μm, preferably 0.05 to 3 μm is suitable.

The charge generation layer is formed of a charge generation material dispersed in a binder resin. As the charge generation material,
τ type metal-free phthalocyanine is used. As the resin forming the charge generation layer, polyvinyl chloride, polyvinyl acetate,
Polyester, vinyl oxide-vinyl acetate copolymer, polyvinyl butyral, polystyrene, polycarbonate,
Acrylic resin, phenol resin, etc. are used. These resins may be used alone or as a mixture. Solvents for the coating liquid used when forming the charge generation layer from these resins include toluene, methylene oxide, monochlorobenzene, methyl alcohol, ethyl alcohol, ethyl acetate, tetrahydrofuran, cyclohexane and the like. These solvents may also be used alone or as a mixture. The film thickness of the charge generation layer is 0.
It is suitable to be about 05 to 5 μm, preferably about 0.1 to 2 μm. When the charge generation layer is used alone, it is 10 to 30 μm.
m, preferably 15 to 20 μm.

When the coating solution for forming the charge generating layer is produced, as a method for dispersing the charge generating material in the coating solution, known methods such as ball mill, sand mill, homomixer, disperser, micronizer and ultrasonic wave are known. Methods are available.

The charge transport layer is formed by incorporating a charge transport material into a suitable binder resin. The charge transport material includes an electron transfer material and a hole transfer material.

Examples of the electron transfer substance include chloranil, bromoanil, tetracyanoethylene, tetracyanoquinodimethane, 2,4,7-trinitro-9-fluorenone, 2,3,5,7-tetranitro-9-fluorenone and the like. There are electron-withdrawing substances and those obtained by polymerizing them.

As the hole transfer material, pyrene, N-ethylcarbazole, N-isopropylcarbazole, N-
Methyl-N-phenylhydrazino-3-methylidene-9
-Ethylcarbazole, N, N-diphenylhydrazino-3-methylidene-9-ethylcarbazole, N, N-
Hydrazones such as diphenylhydrazino-3-methylidene-10-ethylphenothiazine, p-diethylaminobenzaldehyde-N, N-diphenylhydrazone, p-diethylaminobenzaldehyde-N-α-naphthyl-N-phenylhydrazone, 2,5-bis (P-diethylaminophenyl) -1,3,4-oxadiazole,
1-phenyl-3- (p-diethylaminostyryl)-
5- (p-diethylaminophenyl) pyrazolin, 1-
[Quinolyl (2)]-3- (p-diethylaminostyryl) -5- (p-diethylaminophenyl) pyrazoline, 1- [sridyl (3)]-3- (p-diethylaminostyryl) -5- (p-diethylamino) Phenyl) pyrazolins and other pyrazolines, triarylmethane compounds, oxadiazole compounds, thiazole compounds,
There are triphenylamine, poly-N-vinylcarbazole and the like, and these known charge transport materials can be used alone or in combination of two or more.

As the resin for the charge transport layer, polystyrene, ketone resin, phenol resin, polyester, polycarbonate, polyvinyl butyral, polyvinyl formal, polyacrylamide, polyamide and the like are used. These resins may be used alone or as a mixture.
Further, various additives usually used for these resins, for example, an ultraviolet absorber, an antioxidant and the like can be appropriately added. Tetrahydrofuran, dioxane, cyclohexane, toluene, dichloroethane, methylene chloride, monochlorobenzene and the like can be used as the solvent of the coating liquid when the charge transport layer is formed of these resins. These solvents can also be used alone or as a mixture. The thickness of the charge transport layer is 5 to 40 μm, preferably 15 to 25 μm.

As the coating method for forming the photosensitive layer using the coating liquid, known methods such as a spin coater, an applicator, a spray coater, a bar coater, a dip coater and a doctor blade are used. The applied photosensitive layer is dried by heating with hot air, infrared rays or the like.

[0016]

The details of the present invention will be described below with reference to Examples and Comparative Examples.

[Example 1]

Τ-type metal-free phthalocyanine is 1 by dry weight.
Part, perylene-3,4,9,10-tetracarboxylic acid-
0.2 parts of bis (phenethylimide), polyvinyl butyral resin (Sekisui Chemical Co., Ltd .: trade name "BX-1") 1.2
15 parts in a ball mill together with 50 parts of tetrahydrofuran
Time dispersion was performed. Polyamide resin (Teijin Co., Ltd .: trade name "T-8") was applied as an intermediate layer to an aluminum plate having a thickness of 0.2 μm, and this coating material was further applied to a dry film thickness of 0.2 μm to generate an electric charge. Layers were formed. next,
20 parts of the charge transport material represented by the following general formula 2 and a polycarbonate resin (manufactured by Mitsubishi Gas Chemical Co., Inc .: trade name "Z-20"
0 ") was dissolved in 100 parts of methylene chloride to obtain a solution having a dry film thickness of 20 μm, to form a charge transport layer.

Embedded image

In this way, an electrophotographic photosensitive member having a laminated type photosensitive layer was prepared, and the electrophotographic characteristics were evaluated with an electrostatic recording paper tester (Kawaguchi Electric Co., Ltd .: trade name "EPA-8100"). went. That is, the initial potential (V _o ) when charged by a corona discharge of −5 kV, the residual potential (V _reai ), after irradiation with white light of 51 ux for 5 seconds, and the exposure amount required to reduce the initial potential by half. (E _2/1 ) and charge retention rate (DDR) were measured.

[Example 2]

Example 1 was repeated except that the dry weight of the τ-type metal-free phthalocyanine was changed to 0.6 part and perylene-3,4,9,10-tetracarboxylic acid-bis (phenethylimide) was changed to 0.6 part. Similarly, a sample was prepared and evaluated.

[Embodiment 3]

Example 1 was repeated except that the dry weight of the τ-type metal-free phthalocyanine was changed to 0.4 part and 0.8 part of perylene-3,4,9,10-tetracarboxylic acid-bis (phenethylimide). Similarly, a sample was prepared and evaluated.

Comparative Example 1

Samples were prepared and evaluated in the same manner as in Example 1 except that perylene-3,4,9,10-tetracarboxylic acid-bis (phenethylimide) was not contained.

[Comparative Example 2]

1.5 parts by dry weight of τ-type metal-free phthalocyanine, polyvinyl butyral resin (manufactured by Sekisui Chemical Co., Ltd .:
Trade name "BX-1") 1.0 part, tetrahydrofuran 6
Dispersion was carried out for 20 hours with a ball mill together with 0 part. A sample was prepared in the same manner as in Example 1 except for the above.

The results are shown in FIG. In Comparative Example 1, the charge retention rate is low and the sensitivity is high. In Comparative Example 2,
Although the charge retention rate has been improved by changing the ratio of the pigment and the resin, the sensitivity is higher than that of Comparative Example 1. In Examples 1 to 3 in which the perylene-3,4,9,10-tetracarboxylic acid-bis (phenethylimide) of the present invention was contained in the charge generation layer, the object was achieved.

[0029]

As described above, by incorporating perylene-3,4,9,10-tetracarboxylic acid-bis (phenethylimide) in the charge generation layer of an electrophotographic photosensitive member, the charge retention rate is improved. It is possible to provide an electrophotographic photosensitive member having improved sensitivity and adjustable sensitivity.

[Brief description of drawings]

FIG. 1 is a chart showing the evaluation test results of electrophotographic characteristics in Examples 1 to 3 and Comparative Examples 1 and 2.

Claims (5)

[Claims] 1. A laminated organic photoreceptor main body comprising a charge generation layer and a charge transport layer formed on a conductive support, wherein the charge generation layer of the organic photoreceptor main body has a τ-type metal-free material. Phthalocyanine and perylene-3 represented by the following general formula 1,
An electrophotographic photoreceptor containing 4,9,10-tetracarboxylic acid-bis (phenethylimide). Embedded image 2. The perylene-3,4,9,10-tetracarboxylic acid-bis (phenethylimide) is 0.01 to 4 equivalents relative to the τ-type metal-free phthalocyanine. Item 1. The electrophotographic photosensitive member according to item 1. 3. The perylene-3,4,9,10-tetracarboxylic acid-bis (phenethylimide) is 0.2 to 2 equivalents relative to the τ-type metal-free phthalocyanine. Item 1. The electrophotographic photosensitive member according to item 1. 4. The conductive support is formed of any one metal or alloy selected from the group consisting of aluminum, titanium, copper, nickel, zinc and chromium. The electrophotographic photosensitive member described. 5. An intermediate layer is provided between the conductive support and the charge generation layer.
The electrophotographic photosensitive member described.