JPH0677154B2 - Electrophotographic photoconductor - Google Patents

Description

TECHNICAL FIELD The present invention relates to an electrophotographic photoreceptor, and more particularly to an electrophotographic photoreceptor having a photosensitive layer containing an organic photoconductive compound as a main component.

2. Description of the Related Art Generally, in electrophotography, an electrostatic latent image is formed by charging and exposing the surface of a photosensitive layer of a photoconductor, and the latent image is developed by a developer to be visualized. There is a so-called PPC system in which a copy image is obtained by fixing, or a visible image on a photoconductor is transferred onto a transfer paper such as paper, and the transfer image is fixed to obtain a copy image.

Conventionally, inorganic photoconductive materials such as selenium, cadmium sulfide, and zinc oxide are known as photoconductive materials for forming a photosensitive layer of an electrophotographic photosensitive member used for this kind of purpose. These photoconductive materials have a number of advantages, such as being able to be charged to an appropriate potential in the dark, having a low dissipation of charges in the dark, or being capable of rapidly dissipating charges by light irradiation. However, it has various drawbacks.

For example, selenium-based photoconductors are difficult to manufacture, the manufacturing cost is high, and they are vulnerable to heat and mechanical shock, so that they must be handled with care.

Cadmium sulfide-based photoreceptors and zinc oxide photoreceptors do not provide stable sensitivity in humid environments, and the dye added as a sensitizer causes charge deterioration due to corona charging and photobleaching due to exposure, resulting in long-term It has a drawback that it cannot provide stable characteristics.

On the other hand, various organic photoconductive polymers such as polyvinylcarbazole have been proposed, but these polymers are superior in film forming property and lightness to the above-mentioned inorganic photoconductive materials. However, it is still inferior to the inorganic photoconductive material in terms of sufficient sensitivity durability and stability due to environmental changes.

Various researches and developments have been carried out in order to solve these drawbacks and problems, but in recent years, for example, JP-A-50-38543,
JP-A-51-95852, JP-A-53-64040, JP-A-SHO
A photoconductor using a phthalocyanine-based photoconductive material is proposed in Japanese Patent Laid-Open No. 53-83744 and the like. It is known that this type of photoconductor is excellent in processability and sensitivity, has no hygiene problems, and exhibits high sensitivity to long-wavelength light such as a semiconductor laser. However, even with such a phthalocyanine-based binder photoreceptor, although it has the remarkable advantages as described above, fatigue such as a decrease in charging potential and a change in sensitivity due to repeated processes such as charging and exposure can be reduced at an early stage. There was a drawback that occurred. This is because the photoreceptor surface is deteriorated by mechanical factors such as abrasion and chemical factors such as exposure to an oxidizing atmosphere such as ozone generated at the time of corona charging in the process of using the Carlson method. Therefore, JP-A-53
As shown in Japanese Patent Publication No.-44028, there is one in which a protective layer made of resin is provided on the surface of a photoconductor, but it is effective for surface deterioration due to mechanical factors, but the surface caused by ozone etc. It had little effect on deterioration.

As a measure for preventing such surface deterioration due to ozone or the like, a method using an antioxidant is proposed in Japanese Patent Application Laid-Open No. 57-122444. This method involves adding an antioxidant to the surface charge transport layer of the function-separated photoreceptor,
Prevents ozone oxidation.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention In order to solve the deterioration of a single-function type photoreceptor containing a phthalocyanine photoconductive powder in an oxidizing atmosphere such as ozone, an antioxidant as disclosed in JP-A-57-122444 is disclosed. Indiscriminately blended in the photoconductive layer, the excellent photoconductive properties of the phthalocyanine-based photoconductive material are impaired, and a photoreceptor having satisfactory performance cannot be obtained.

Means for Solving the Problems The present invention prevents deterioration due to an oxidizing atmosphere generated during corona charging by incorporating a primary or secondary amine compound into a photoconductive layer containing a phthalocyanine photoconductive material. Also, a photoreceptor having excellent photoconductive properties is obtained. The primary or secondary amine compound is considered to have a neutralizing or reducing action on the phthalocyanine photoconductor.

The photoconductor of the present invention is not limited to a single-function photoconductor, but can be applied to a multi-function photoconductor.

The present invention relates to an electrophotographic photoreceptor including a photosensitive layer in which a phthalocyanine photoconductive material powder is dispersed in a binder resin. In the photosensitive layer, a primary or secondary amine compound is added to the phthalocyanine photoconductive layer. The present invention relates to an electrophotographic photoconductor characterized by containing 0.5 to 50% by weight based on the material.

As the phthalocyanine-based photoconductive material used in the present invention, any phthalocyanine known per se and derivatives thereof can be used, and specifically, copper, silver, beryllium, magnesium, calcium, gallium, zinc, cadmium, barium, Mercury, aluminum, indium,
Lanthanum, neodymium, samarium, europium, gadolinium, dysprosium, holmium, sodium, lithium, ytterbium, lutetium, titanium,
Examples include tin, hafnium, lead, thorium, vanadium, antimony, chromium, molybdenum, uranium, manganese, iron, cobalt, nickel, rhodium, palladium, osmium and platinum. Further, the central nucleus of phthalocyanine may be not a metal atom but a metal halide having a valence of 3 or more. Further, derivatives of (non) metal phthalocyanine such as copper-4-aminophthalocyanine, iron polyhalophthalocyanine, cobalt hexaphenylphthalocyanine, vanadyl phthalocyanine, tetraazo phthalocyanine, tetramethylphthalocyanine and dialkylaminophthalocyanine can be used. These can be used alone or in combination. Phthalocyanine derivative in which hydrogen atom of benzene nucleus in phthalocyanine molecule is substituted with at least one electron-withdrawing group selected from the group consisting of nitro group, cyano group, halogen atom, sulfone group and carboxyl group, and phthalocyanine and said phthalocyanine Use a phthalocyanine-based photoconductive material composition obtained by mixing at least one kind of an unsubstituted phthalocyanine compound selected from compounds with an inorganic acid capable of forming a salt with them and precipitating with water or a basic substance. You can also do it. In this case, the electron-withdrawing group-substituted phthalocyanine derivative has 1 substituent in one molecule.
Any of up to 16 can be used, and the composition ratio of the electron-withdrawing group-substituted phthalocyanine derivative to another unsubstituted phthalocyanine compound is such that the number of substituents in the former is one unit phthalocyanine molecule in the composition. It is preferable that the number is 0.001 to 2, and preferably 0.002 to 1. As the inorganic acid capable of forming a salt with the phthalocyanine compound used in producing the phthalocyanine-based photoconductive material composition, sulfuric acid, orthophosphoric acid, chlorosulfonic acid, hydrochloric acid, hydroiodic acid, hydrofluoric acid, Examples thereof include hydrobromic acid.

Among the above-mentioned photoconductive materials, metal-free phthalocyanine, copper phthalocyanine and derivatives thereof, such as nuclear electron-withdrawing group substituted derivatives, are particularly preferable for achieving the object of the present invention.

As the electrically insulating binder in the present invention, all known electrically insulating binders such as a thermoplastic resin, a thermosetting resin, a photocurable resin, a photoconductive resin and the like can be used. Examples of suitable binder resins include, but are not limited to, saturated polyester resins, polyamide resins, acrylic resins, ethylene-vinyl acetate copolymers, ion-crosslinked olefin copolymers (ionomers), styrene- Butadiene block copolymer, polycarbonate,
Thermoplastic binder such as vinyl chloride-vinyl acetate copolymer, cellulose ester, polyimide, styrene resin;
Thermosetting binder such as epoxy resin, urethane resin, silicone resin, phenol resin, melamine resin, xylene resin, alkyd resin, thermosetting acrylic resin; photocurable resin; poly-N-vinylcarbazole, polyvinylpyrene, It is a photoconductive resin such as polyvinyl anthracene. These can be used alone or in combination.

These electrically insulating resins are individually measured to be 1 × 10 ¹² Ω ・
It is desirable to have a volume resistance of cm or more.

The conductive support used in the electrophotographic photosensitive member of the present invention, copper, aluminum, silver, iron, a foil or plate of nickel or the like is used in a sheet or drum shape,
Alternatively, these metals are vacuum-deposited or electroless-plated on a plastic film, or a layer of a conductive compound such as a conductive polymer, indium oxide or tin oxide is applied or vapor-deposited on a support such as paper or a plastic film. The one provided by

Examples of the primary or secondary amine compound used in the present invention include a phenylenediamine compound, a diphenylamine compound, a dihydroquinoline compound, a benzimidazole compound, a benzotriazole compound, an indole compound, a phenothiazine compound, a carbazole compound, an aminocarboxylic acid compound and an amic acid. It is a compound. Specific examples of compounds include p-phenylenediamine, N-isopropyl-N'-phenyl-p-phenylenediamine, and N- (1-methylheptyl) -N'-phenyl-p-phenylenediamine as phenylenediamine compounds. , N,
N'-diphenyl-p-phenylenediamine, N, N'-di-2-naphthyl-p-phenylenediamine, diphenylamine compounds such as octyldiphenylamine, acetyldiphenylamine, 4-aminodiphenylamine,
Examples of the dihydroquinoline compound include 1,2-dihydroquinoline, 2,2,4-trimethyl-1,2-dihydroquinoline, 6
-Ethoxy-2,2,4-trimethyl-1,2-dihydroquinoline, benzimidazole compounds include benzimidazole, 2-mercaptobenzimidazole, 2-phenylbenzimidazole, 5-aminobenzimidazole, 5-nitrobenzimidazole. As the indole compound, indole, acetylindole, indokun, 3-methylindole, and as the phenothiazine compound, phenothiazine, 7-amino-3-imino-3H-
Phenothiazine thionine, 3,7-dimethylphenothiazine, and carbazole compounds include carbazole and 3-
Chlorocarbazole, 3-methylcarbazole, and harmine benzotriazole compounds include 1,2,3-benzotriazole, 8-azo-adenine, 8-azo-xanthine, 8-azoguanine, 8-azo-hypoxanthine,
Aminocarboxylic acid compounds include glycine, 2-aminopropionic acid, 2-aminobutyric acid, 2-amino-3-hydroxypropionic acid, ornithine, arginine, aspartic acid, glutamic acid, glutamine, glycylglycine, 2-prolidone, 2 -Piperidone, ε-caprolactam, and amic acid compounds include, but are not limited to, carbamic acid, ammonium carbamate, acetyl urethane, ethyl oxamate, and the like. In addition, these primary or secondary amine compounds are added to
You may use it in combination.

The amine compound used in the present invention is a primary or secondary amine because the active hydrogen on the nitrogen atom of the amino group is important for adsorbing the amine compound on the phthalocyanine photoconductor material. is there. The amine compound is preferably surface-coated or adsorbed on the phthalocyanine-based photoconductor material and then dispersed in the resin, whereby the surface potential can be further stabilized, and the object of the present invention can be more effectively achieved. You can

As described above, the photoconductor of the present invention is prepared by kneading and dispersing a photoconductive material in a primary or secondary amine compound and a binder resin together with a solvent to prepare a photosensitive coating solution, which is directly applied onto a conductive substrate. Alternatively, it is provided by coating on the intermediate layer formed thereon and drying to form a photosensitive layer.

The amount of the primary or secondary amine compound used in the present invention is 0.5 to 50% by weight, preferably 1 to 3% based on phthalocyanine.
It is 0% by weight.

Regarding the blending ratio of the phthalocyanine-based photoconductive material and the binder resin, the sensitivity improves as the former amount increases, but dark decay increases remarkably and it becomes difficult to retain the charge.
Since the practicability becomes poor, but the sensitivity is lowered, the amount of the photoconductive material is 5 to 100 parts by weight, preferably 10 to 60 parts by weight, based on 100 parts by weight of the binder resin. .

An electron-donating substance or an electron-accepting substance which is generally known as a sensitizer may be added to the photosensitive layer.
It may be an electrophotographic photoreceptor in which a barrier layer, an insulating layer, and a photosensitive layer of another photoconductor material are laminated.

EFFECTS OF THE INVENTION The photoconductor obtained in the present invention has improved environmental stability and improved aging of the photoconductor, and deterioration of copying characteristics due to repeated use can be suppressed.

Hereinafter, the present invention will be described with reference to examples.

Example 1 20 parts by weight of ε-type copper phthalocyanine, 0.3 parts by weight of 2,4,5,7-tetranitro-9-fluorenone, 1 part by weight of 2-mercaptobenzimidazole, and an acrylic resin (Acrydeic A405: Dainippon Ink and Chemicals Co., Ltd. )) And 6 parts by weight of melamine resin (Super Beckamine J820: Dainippon Ink and Chemicals, Inc.) together with 80 parts by weight of cellosolve acetate / methyl ethyl ketone (1: 1) in a ball mill pot and kneaded for 48 hours. A photoconductive coating material in which photoconductive material powder is uniformly dispersed is prepared, and the coating material is applied onto an aluminum substrate, dried, and then cured by heating to produce an electrophotographic photoreceptor having a photoconductive layer with a thickness of 10 μm. did.

Example 2 An electrophotographic photoreceptor having a photoconductive layer of 10 μm was prepared in the same manner as in Example 1 except that the amine compound was changed from 2-mercaptobenzimidazole to octyldiphenylamine.

Example 3 10 parts by weight of ε-type copper phthalocyanine, 45 parts by weight of N-ethylcarbazole-3-aldehyde-methylphenylhydrazone, 1 part by weight of N, N′-di-2-naphthyl-p-phenylenediamine, polyester resin (Vylon 200: 45 parts by weight of Toyobo Co., Ltd. and polycarbonate resin (Panlite K1300: Teijin Chemicals Co., Ltd.) together with 100 parts by weight of toluene / tetrahydrofuran (1: 9) were put in a ball mill pot and kneaded for 48 hours to obtain light. A photoconductive coating material in which conductive material powder was uniformly dispersed was prepared, and the coating material was applied onto an aluminum substrate and dried to prepare a photoreceptor having a photoconductive layer having a thickness of 10 μm.

Example 4 In the formulation of Example 3, the amine compound was replaced with N, N′-di-2.
A photoreceptor having a photoconductive layer having a thickness of 10 μm was prepared in the same manner as in Example 1 except that naphthyl-p-phenylenediamine was changed to phenothiazine.

Example 5 50 parts by weight of copper phthalocyanine and 0.2 parts by weight of tetranitrocopper phthalocyanine were dissolved in 1000 parts by weight of 98% concentrated sulfuric acid with sufficient stirring, and this was poured into 3000 parts by weight of water to obtain photoconductivity of copper phthalocyanine and tetranitrocopper phthalocyanine. After the material composition was deposited, it was washed with water and dried at 120 ° C. under reduced pressure.

15 parts by weight of this photoconductive material composition, 32 parts by weight of fluorine-containing acrylic resin, melamine resin (Super Beckamine J82
0: Dainippon Ink and Chemicals, Inc.) 8 parts by weight and a composition comprising 1 part by weight of acetylindole and 80 parts by weight of a mixed solvent of cellosolve acetate / methyl isobutyl ketone (1: 1) was used. Similarly, a photoreceptor having a photoconductive layer having a thickness of 10 μm was prepared.

Example 6 15 parts by weight of the photoconductive material composition obtained in Example 5, p-
Diethylaminobenzaldehyde diphenylhydrazone
Using a composition comprising 20 parts by weight, 32 parts by weight of a fluorine-containing acrylic resin, 8 parts by weight of melamine resin, 1.5 parts by weight of acetyldiphenylamine and 80 parts by weight of a mixed solvent of cellosolve acetate / methyl isobutyl ketone (1: 1),
A photoreceptor having a photoconductive layer having a thickness of 10 μm was prepared in the same manner as in Example 1.

Example 7 10 parts by weight of the photoconductive material composition obtained in Example 5, 6-
1 part by weight of ethoxy-2,2,4-trimethyl-1,2-dihydroquinoline was dispersed in a ball mill together with 30 parts by weight of acetone and dried to adsorb an amine compound on phthalocyanine,
Cover.

Acrylic resin (Acridic A405)
25 parts by weight, melamine resin (Super Beckamine J820) 5
A photoconductive layer having a thickness of 10 μm was prepared in the same manner as in Example 1 by using a composition comprising 1 part by weight, 15 parts by weight of p-diethylaminobenzaldehyde diphenylhydrazone and 80 parts by weight of a mixed solvent of cellosolve acetate / methyl isobutyl ketone (1: 1). A photoreceptor having a layer was prepared.

Comparative Example 1 An electrophotographic photoreceptor having a photoconductive layer having a thickness of 10 μm was prepared in exactly the same formulation as in Example 1 except that 2-mercaptobenzimidazole was not added.

Comparative Example 2 A photoreceptor having a photoconductive layer of 10 μm was prepared in exactly the same formulation as in Example 3 except that N, N′-di-2-naphthyl-p-phenylenediamine was not added.

Comparative Example 3 A photoconductor having a photoconductive layer of 10 μm was prepared in exactly the same formulation as in Example 5 except that acetylindole was not added.

Comparative Example 4 A photoconductor having a photoconductive layer of 10 μm was prepared in exactly the same formulation as in Example 7 except that it was not previously treated with an amine compound.

Example 8 The amine compound was treated with 6-ethoxy-2,2,4-trimethyl-1,2.
A photoconductor having a photoconductive layer of 10 μm was prepared in exactly the same formulation as in Example 7 except that glycylglycine was changed from dihydroquinoline.

Example 9 10 parts by weight of the photoconductive material composition obtained in Example 5, 25 parts by weight of acrylic resin (Acridic A405), 5 parts by weight of melamine resin (Super Beckamine J820), p-diethylaminobenzaldehyde diphenylhydrazone. Using a composition comprising 15 parts by weight, 3 parts by weight of 3-phenylcarbazole, and 80 parts by weight of a mixed solvent of cellosolve acetate / methylisobutylketone (1: 1), a light having a thickness of 10 μm was prepared in the same manner as in Example 1. A photoconductor having a conductive layer was prepared.

Example 10 A photoconductor having a photoconductive layer having a thickness of 10 μm was prepared in the same manner as in Example 9 except that the amount of 3-phenylcarbazole was changed to 5 parts by weight.

Each of the 14 types of photoconductors prepared as described above was commercially available as a powder image transfer type electrophotographic copying machine (manufactured by Minolta Camera Co., Ltd .: EP-350).
Z) built-in as a photoconductor + 6KV corona discharge, the initial surface potential (V _o ), the amount of exposure required to reduce the initial surface potential to 1/2 (E _1/2 (lux · sec)), and charging and discharging. After repeating 3000 cycles, V _o and E _1/2 were examined.

The results are shown in Table-1.

As is clear from the results shown in Table-1, the photoreceptor of the present invention is
Excellent in repeatability and durability.

The photoconductor of the present invention is a photoconductor for electrophotography which exhibits excellent properties for general copying machines and laser printers.

Claims (1)

[Claims] 1. A photoconductor for electrophotography comprising a photosensitive layer comprising a phthalocyanine photoconductive material powder dispersed in a binder resin, wherein a primary or secondary amine compound is added to the photosensitive layer. 0.5 to 50 for conductive materials
A photoconductor for electrophotography, characterized in that the photoconductor is contained in a weight percentage.