JPS6177054A - Photosensitive body - Google Patents

Abstract

PURPOSE:To enhance ozone resistance and to stabilize repetition characteristics by forming a photosensitive layer contg. a phthalocyanine type photoconductor powder and a plane type condensed polycyclic compd. having >=3 rings dispersed into a binder on a substrate. CONSTITUTION:A photosensitive coating fluid is prepared by kneading and dispersing the phthalocyanine type photoconductor powder and a plane type condensed polycyclic compd. having >=3 rings together with the binder in a solvent. As the phthalocyanine photoconductor, metal-free phthalocyanine, copper phthalocyanine, and their derivs. are suitable. As the polycyclic compd., anthracene type compds., such as anthracene and phenyl anthracene, are suitable. The conductive substrate, directly, or an interlayer formed on the conductive substrate is coated with said coating fluid to form the photosensitive layer, thus forming a photosensitive body.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a photoreceptor, and more particularly to a photoreceptor having a photosensitive layer containing an organic photoconductive compound as a main component.

Conventional technology In general, in electrophotography, the surface of the photosensitive layer of a photoreceptor is charged and exposed to form an electrostatic latent image, which is developed with a developer to make it visible, and the visible image is directly transferred onto the photoreceptor as it is. There is a so-called PPC method, in which a visible image on a photoreceptor is transferred onto a transfer paper such as paper and the transferred image is fixed to obtain a copied image.

Conventionally, inorganic photoconductive materials such as carbon dioxide, selenium, cadmium sulfide, and zinc oxide are known as photoconductive materials for forming the photosensitive layer of photoconductors used for this type of purpose. These photoconductive materials have many advantages, such as being able to be charged to an appropriate potential in the dark, having little charge dissipation in the dark, or being able to quickly dissipate charge when irradiated with light. On the other hand, it also has various drawbacks.

For example, micellenic photoreceptors require difficult manufacturing conditions, are expensive to manufacture, and are sensitive to heat and mechanical shock, so care must be taken when handling them.

With cadmium sulfide photoreceptors and zinc oxide photoreceptors, stable sensitivity cannot be obtained in humid environments, and the dyes added as sensitizers cause charge deterioration due to corona charging and photobleaching due to exposure, so they cannot be used for long periods of time. It has the disadvantage that it cannot provide stable characteristics.

On the other hand, various organic photoconductive polymers including polyvinylcarbazole have been proposed, but these polymers are superior to the above-mentioned inorganic photoconductive materials in terms of film formability and light weight. However, they are still inferior to inorganic photoconductive materials in terms of sufficient sensitivity durability and stability against environmental changes.

Various research and developments have been conducted to solve these drawbacks and problems, but in recent years, for example, Japanese Patent Application Laid-Open No. 50-38543
No. 1, JP-A-51-95852, JP-A-53-
Photoreceptors using phthalocyanine-based photoconductive materials have been proposed in Japanese Patent Laid-Open No. 64040, Japanese Patent Laid-Open No. 53-83744, and the like. It is known that this type of photoreceptor has excellent processability and sensitivity, has no hygienic problems, and exhibits high sensitivity even to long wavelength light such as that of a semiconductor laser. However, although such phthalocyanine-based binder photoreceptors have the remarkable advantages mentioned above, they suffer from early fatigue in which the charging potential decreases and the sensitivity changes due to repeated processes such as charging and exposure. There were some drawbacks. This is because the surface of the photoreceptor deteriorates due to mechanical factors such as wear, or chemical factors such as exposure to an oxidizing atmosphere such as ozone generated during corona charging during the process of using the curling method. be. Therefore, as shown in Japanese Patent Application Laid-Open No. 53-44028, there is a method in which the surface of the photoreceptor is provided with a protective layer made of resin, but although this is effective against surface deterioration due to mechanical factors, It was not very effective against surface deterioration caused by ozone and the like.

Problems to be Solved by the Invention As mentioned above, in single-function photoreceptors using phthalocyanine-based photoconductive materials, when exposed to an oxidizing atmosphere such as ozone, the phthalocyanine adsorbs active gases and deteriorates. The surface potential decreases. As a result, the characteristics of the photoreceptor change over time and the repeatability deteriorates.

SUMMARY OF THE INVENTION The present invention aims to solve the above-mentioned problems, and provides a photoreceptor in which a phthalocyanine-based photoconductive material, which has excellent ozone resistance and stable repeatability without changing over time, is dispersed in a binder. shall be.

By incorporating the cyanine-based photoconductive material into a photoconductive layer, a photoreceptor can be obtained which prevents deterioration due to the oxidizing atmosphere generated during corona charging and has excellent photoconductive properties. This is because the condensed polycyclic compound is selectively adsorbed on phthalocyanine and phthalocyanine destroys active sites that can adsorb active gases such as ozone, thereby preventing deterioration.

The photoreceptor of the present invention can be applied not only to a single-function photoreceptor but also to a multi-function photoreceptor.

The present invention provides an electrophotographic photoreceptor in which a photosensitive layer formed by dispersing phthalocyanine-based photoconductive material powder in a binder is formed on a substrate. The present invention relates to an electrophotographic photoreceptor characterized by containing a compound.

The phthalocyanine-based photoconductive materials used in the present invention include phthalocyanines and their derivatives, which are known per se.
Cadmium, barium, mercury, aluminum, nickel, lanthanum, neodymium, samarium, europium, gadolinium, dysprosium, holminium, sodium, lithium, ytterbium, lutetium, titanium, tin, hafnium, lead, thorium, vanadium, antimony, chromium, molybdenum, uranium, manganese, iron,
These include cobalt, nickel, rhodium, palladium, osmium and platinum. Furthermore, the central nucleus of the phthalocyanine may not be a metal atom, but a metal halide having a valence of 3 or more. In addition, copper-4-aminophthalocyanine, iron polyhalophthalocyanine, cobalt hexaphenylphthalocyanine and vanadyl phthalocyanine,
Derivatives of (non-)metal phthalocyanine such as tetraazo phthalocyanine, tetramethyl phthalocyanine, and dialkylaminophthalocyanine can be used. These can be used alone or in combination.

A phthalocyanine derivative in which the hydrogen atom of the benzene nucleus in the phthalocyanine molecule is substituted with at least one electron-withdrawing group selected from the group consisting of a nitro group, a cyano group, a halogen atom, a sulfone group, and a carboxyl group, and a phthalocyanine and the phthalonanine. A phthalocyanine-based photoconductive material composition is used, which is obtained by mixing at least one unsubstituted phthalocyanine compound selected from the compounds with an inorganic acid that forms a salt with them, and precipitating the mixture with water or a basic substance. You can also do that.

In this case, the electron-withdrawing group-substituted phthalocyanine derivative is
-Any number of substituents in the molecule can be used from 1 to 16, and the composition ratio of the electron-withdrawing group-substituted phthalocyanine derivative and other unsubstituted phthalocyanine compounds is as follows:
The number of the former substituents is 0.001 to 2, preferably 0.002 per molecule of phthalocyanine unit in the composition.
It is best to have ~1 piece. Inorganic acids that can form a salt with the phthalocyanine compound used in producing the phthalocyanine-based photoconductive material composition include sulfuric acid,
Examples include orthophosphoric acid, chlorosulfonic acid, hydrochloric acid, hydroiodic acid, hydrofluoric acid, and hydrogen bromide.

Among the photoconductive materials, those particularly suitable for achieving the object of the present invention include metal-free phthalocyanine, copper phthalocyanine, and derivatives thereof, such as derivatives substituted with nuclear electron-withdrawing groups.

Examples of the electrically insulating binder in the present invention include electrically insulating thermoplastic resins known per se, mixed polyester resins, polyamide resins, acrylic resins, ethylene-vinyl acetate copolymers, and ionically crosslinked olefin copolymers. (ionomer), styrene-butadiene broccoli copolymer, polycarbonate, vinyl chloride-vinyl acetate copolymer, cellulose ester, polyimide, styrene resin, and other thermoplastic binders: epoxy resin, urethane resin, silicone resin, phenol Thermosetting binders such as resins, melamine resins, xylene resins, alkyd resins, thermosetting acrylic resins; photocurable resins; photoconductive resins such as poly-N-vinylcarbazole, polyvinylpyrene, polyvinylanthracene, etc. be. These can be used alone or in combination.

These electrically insulating resins have a resistance of 1×100 when measured individually.
It is desirable to have a volume resistivity of m or more.

The conductive support used in the photoreceptor of the present invention may be a sheet or drum-shaped foil or plate of copper, aluminum, silver, iron, nickel, etc., or these metals may be used in the form of a plastic film, etc. vacuum evaporation or electroless plating, or a layer of a conductive compound such as a conductive polymer, indium oxide, or tin oxide applied to a support such as paper or plastic film by coating or vapor deposition. is used.

Examples of the planar fused polycyclic compound having three or more rings used in the present invention include anthracene-based anthracene, phenylanthracene, 9-anthrol, chloroanthracene, and 10-phenylanthrone, fluorene-based fluorene, 9-phenylfluorenone, and fluorenone. and 9-fluorethur, anthraquinone series anthraquinone, hydroxyanthraquinone, 2-methylanthraquinone and aminoanthraquinone, phenanthrene series phenanthrene, phenanthrene, phenanthrene series, bimanthrene and phenanthraquinone, fused tetracyclic series pyrene, naphthacene, chrysene , 1.6-pyrenequinone, triphenylene, 1.8-pyrenequinone, benzanthracene and penzanthrene, fused polycyclic compounds pentacene, pentaphene, picene, perylene, benzopyrene, coronene, pyrantrene and dibenzanthracene, heterofused polycyclic compounds dibenzofuran, Xanthine, 9-xanthenol, 9-xanthenone, thioxanthin, thioxanthone, dibenzothiophene, carbazole, juloliden, porphyrin, hemin, indigo, acridine, 9-
Phenylacridine, iminostilbene, benzoquinoline, naphthoquinolin, γ-anthraquino. Examples include, but are not limited to, chlorophyll, phenanthroline, amarone, phenazine, phenoxazine, phenothiazine, and derivatives thereof.

Since these compounds having a planar structure have a planar structure, phthalocyanine itself is thought to selectively interact with the phthalocyanine and adsorb the phthalocyanine. Therefore, the active sites of phthalocyanine are protected and deterioration by active gases such as ozone is prevented. As for compounds, the closer the planar structure of phthalocyanine is, the easier it is to be adsorbed, and the greater the deterioration prevention effect. In addition, the above-mentioned fused polycyclic compounds may be used in combination of two or more types.

By coating or adsorbing the fused polycyclic compound used in the present invention on the surface of a phthalocyanine-based photoconductor material and then dispersing it in a resin, the surface potential can be further stabilized, and the present invention can be more effectively carried out. You can achieve your goals.

The photoreceptor of the present invention is produced by cross-dispersing a photoconductive material in a condensed polycyclic compound and a binder resin together with a solvent as described above to prepare a photosensitive coating solution, which is applied directly onto a conductive substrate or It is provided by coating the intermediate layer formed thereon and drying it to form a photosensitive layer.

The amount of the fused polycyclic compound used in the present invention is 0.5 to 50% by weight, preferably 1 to 30% by weight, based on the phthalocyanine. There is no effect if it is less than 0.5% by weight;
If the amount exceeds % by weight, properties such as photosensitivity will deteriorate.

Regarding the blending ratio of the phthalocyanine-based photoconductive material and the binder resin, increasing the amount of the former improves sensitivity, but dark decay increases significantly and charge retention becomes difficult, making it impractical. However, since the sensitivity decreases, the amount of the photoconductive material is preferably 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, and in addition to the photosensitive layer,
A photoreceptor may be formed by stacking a barrier layer, an insulating layer, and a photosensitive layer of another photoconductor material.

Effects of the Invention The photoreceptor obtained by the present invention has improved environmental stability, improved aging of the photoreceptor, and can suppress deterioration of copying characteristics due to repeated use.

The present invention will be explained below with reference to Examples.

Example 1 10 parts by weight of ε-type copper phthalocyanine, 0.3 parts by weight of 2,45.7-tetranitro-9-fluorenone, 1 part by weight of phenothiazine, 45 parts by weight of N-ethylcarbazole-3-aldehyde-methylphenylhydrazone, polyester 45 parts by weight of resin (Vylon 200: manufactured by Toyobo Co., Ltd.), and polycarbonate resin (1300 parts by weight for Panlite).
: manufactured by Kijin Kasei Co., Ltd.) in a ball mill pot with 100 parts by weight of toluene/tetrahydrofuran (1:9) and kneaded for 48 hours to prepare a photoconductive paint in which the photoconductive material was uniformly dispersed. This was coated onto an aluminum substrate and dried to produce an electrophotographic photoreceptor having a photoconductive layer with a thickness of 10 μm.

Example 2 L was prepared in the same manner as in Example 1 except that phenothiazine was changed to 9=phenylcarbazole in the formulation of Example 1.
A photoreceptor having a photoconductive layer with a thickness of Oμ was produced.

Example 3 A photoreceptor having a photoconductive layer having a thickness of 10 μm was prepared in the same manner as in Example 1, except that thioxanthin was used instead of 7-enothiazine.

Example 4 50 parts by weight of copper phthalocyanine and 0.2 parts by weight of copper tetranitro phthalocyanine were dissolved in 500 parts by weight of 98% concentrated sulfuric acid with thorough stirring, and this was poured into 3000 parts by weight of water, and the copper phthalocyanine and copper tetranitro phthalocyanine were dissolved in light. After precipitating the conductive material composition, it was filtered, washed with water, and dried at 120° C. under reduced pressure. 10 parts by weight of the obtained composition, 25 parts by weight of acrylic resin (Acridic A405),
Examples were carried out using a composition consisting of 5 parts by weight of melamine resin (Super Beckermine J820), 15 parts by weight of 2-methoxy-4-dibenzylamino benzaldehyde diphenylhydrazone, 22 parts by weight of phenane, and 80 parts by weight of methyl ethyl ketone. 10 in the same way as 1
A photoreceptor having a μ-thick photoconductive layer was produced.

Example 5 A photoreceptor having a photoconductive layer having a thickness of 10 μm was prepared in the same manner as in Example 4, except that pyrene was used instead of phenonthrene in the recipe.

Example 6 10 parts by weight of the photoconductive material composition obtained in Example 5 and 1 part by weight of phenoxazine are dispersed in a ball mill with 30 parts by weight of acetone, and then dried to adsorb and coat the phenoxazine on the phthalocyanine. The resulting composition was mixed with 25 parts by weight of acrylic resin, 5 parts by weight of melamine resin, 15 parts by weight of N-ethylcarbazole-3-aldehyde-diphenylhydrazone, 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 using the composition consisting of the following.

Example 7 A photoreceptor having a photoconductive layer having a thickness of 10 μm was prepared using the same recipe as in Example 6 except that the amount of phenoxazine was changed to 3 parts by weight.

Example 8 A photoreceptor having a photoconductive layer having a thickness of 10 μm was prepared using the same recipe as in Example 6 except that the amount of phenoxazine was changed to 5 parts by weight.

Comparative Example 1 A photoreceptor having a photoconductive layer of 10 μm was prepared using the same formulation as in Example 1 except that phenothiazine was not added.

Comparative Example 2 A photoreceptor having a photoconductive layer of 10 μm was prepared using the same recipe as in Example 4 except that phenanthrene was not added.

Comparative Example 3 A photoreceptor having a photoconductive layer of 1Oμ was produced using the same recipe as in Example 6 except that no treatment with phenoxazine was performed.

:Ep-3502) is installed as a photoreceptor with a +6KV corona discharge, the initial surface potential (vO), and the exposure amount (E) required to bring the initial surface potential to
) ) and ■0 and E in the atmosphere after 3000 cycles of charging and neutralization were investigated. The results are shown in Table-1.

As is clear from the results in Table 1, the surface potential (Vo) and sensitivity (p-'4> of the photoreceptor of the present invention hardly decreased compared to the initial state even after 3000 cycles, and there was no change over time.
It showed excellent repeatability (ζ).

Margin below Table-1

Claims (1)

[Claims] 1. A photoreceptor in which a photosensitive layer formed by dispersing phthalocyanine-based photoconductive material powder in a binder is formed on a substrate, and the photosensitive layer contains a planar fused polycyclic compound of three or more rings. A photoreceptor characterized by: