JPS6214158A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To enhance sensitivity and durability by incorporating a combination of a specified pigment and a binder resin in a photosensitive layer. CONSTITUTION:The electrophotographic sensitive body has the photosensitive layer formed on a conductive substrate, and the photosensitive layer contains at least one of the anthanthrone pigments represented by formula (1) and a polycarbonate Z resin represented by formula (2), thus permitting the photosensitive layer to be high in sensitivity and small in residual potential and stable in the potential in the light parts and prevented from rise of said potential at the time of repeated cycles of electrification and exposure. The presence of the polycarbonate Z resin on the surface permits the photosensitive layer to be high in surface hardness, superior in lubricity, resistant to scratches, and enhanced in mechanical durability, and further, to be enhanced in productivity by the good storage stability of the coating solution of the polycarbonate Z resin, and stabilized in quality.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field to which the invention pertains] The present invention relates to an electrophotographic photoreceptor, and in particular, to an anthorone pigment and an anthothrone pigment. The present invention relates to an electrophotographic photoreceptor having a photosensitive layer containing a recarbonate Z resin and having improved characteristics.

[Conventional technology]

Conventional electrophotographic photoreceptors include those using inorganic photoconductive materials such as selenium, cadmium sulfide, and zinc oxide, as well as those using amorphous FJ mixtures, and those using photoconductive materials such as poly-N-vinylcarbazole and polyvinylanthra7ane. Polymers, various low molecular weight organic photoconductive substances such as Hanoethylaminobenzaltehyde N, N-Nof, and Nylhydrazone, 11
Products in which mechanical pigments are dispersed are known. Among these, organic pigments used in electrophotographic photoreceptors include azo pigments such as Sudan Red and Guianpuru, nosazo pigments,
Quinone pigments such as Algol Yellow and Pyrenequinone,
Examples thereof include indigo pigments such as quinocyanine pigments, zerylene pigments, indigo and thioinnocoin, bisbenzimidazole pigments such as indofast olene toner, phthalocyanine pigments such as phthalonanine, and quinacridone pigments.

Although some photoreceptors having these pigments dispersed therein have been put to practical use, their sensitivity and sensitivity have not been sufficiently satisfied. This is because a binder is required for film formation in the case of a notification charge, and this binder impairs the movement of charges. Therefore, when using pigments, it is essential to use a binder that is optimal for the pigments. .

On the other hand, in the case of a functionally separated type photosensitive layer, a pigment is used in the charge generation layer, in which the photosensitive layer is divided into a functionally separated type photosensitive layer, in which the charge generating layer 1 generates charges by light and the charge transport layer 1i transports the charges. In this case, not only the binder of the charge generation layer but also the binder of the carrier for transporting the carrier becomes a factor in determining the sensitivity. In other words, the key to high sensitivity is to efficiently inject the charges generated in the charge generation layer into the charge transport layer, but if the combination of the pigment in the charge generation layer and the binder in the charge transport layer is poor,
A barrier to charge injection is formed at the interface between both layers, and the injection efficiency is partially reduced. Therefore, even in the functionally separated photosensitive layer, a binder for the charge transport layer that is optimal for the pigment is essential.

By the way, polycarbonate resins generally have characteristics such as being transparent, electrically insulating, having high voltage resistance, not interfering with the charge mobility of charge transport materials, and having good mechanical durability and abrasion resistance. Therefore, it has been proposed to use it as a binder for charge transport layers. However, a typical polycarbonate resin, bisphenol A type polycarbonate resin (
Polycarbonate A resin (hereinafter referred to as polycarbonate A resin) has a highly crystalline polymer, so it has poor solubility in the solvent used in the coating solution, and the solution becomes unusable within a few days, resulting in poor photoreceptor productivity. .

[Problem that the invention seeks to solve]

In view of the above-mentioned conventional techniques, an object of the present invention is to provide an electrophotographic photoreceptor with higher sensitivity by combining a specific pigment contained in a photosensitive layer with a binder resin. Another object of the present invention is to provide an electrophotographic photoreceptor with improved durability. Still another object is to provide an electron quadruple photoreceptor with improved productivity and stable quality.

[Means for solving problems]

In the electrophotographic photoreceptor in which a photosensitive layer is provided on a conductive substrate according to the present invention, the photosensitive layer has the following general formula (1), (in the formula
represents a logon atom, nitro, anno, anru or carboxyl group, and indicates the number of n tri O to 4)
Electrophotography characterized by containing at least one anthantrone pigment represented by the following, a polycar represented by the following general formula (2) (wherein m represents an integer of 50 to 5000), and a y4-1z resin. A photoreceptor is provided.

-y The an-anthrone pigment can be represented by the formula +++.

Compared to other organic pigments, it has high sensitivity and less deterioration due to light irradiation.
It is highly durable. Furthermore, by combining polycargay L-IZ [fat of general formula (11)], a photosensitive layer with high sensitivity and high durability with little mechanical surface deterioration can be formed.

An example of an anthrone pigment represented by general formula (1) will be given.

Exemplary Compound 30, Q 31, 032゜33゜35゜Furthermore, the I liquor nate 2 resin of general formula (2) used in the present invention is a polycarbonate resin different from the conventionally used polycargonate A resin. It has good solubility in various solvents while maintaining the mechanical durability of cargonate resin, and the solution has good stability without gelling even after a long period of time, which improves the productivity of photoreceptors. It greatly contributes to the improvement of

By combining the anthoanthrone pigment of the present invention with a polycarbonate resin, the extent to which a barrier layer is formed at the interface between the pigment particles and the resin to prevent the movement of charges during light irradiation is significantly greater than when combining with other than polycarbonate Z resin. It is believed that the small benzene ring and cyclohexyl group of the polycarbonate Z resin structure facilitate charge transfer and improve sensitivity.

The form of the electrophotographic photoreceptor according to the present invention is (a)
A photosensitive layer in which an anthrone pigment is dispersed in polycarbonate 2 resin, (b) an anthrone pigment dispersed in a polycarbonate resin? Nate z
A photosensitive layer dispersed in a resin and a charge transporting compound (electron-donating compound and/or electron-accepting compound);
The 'ti1 generation layer is a layer dispersed in a resin (or other resins), and on top of this is a layer dispersed in a polycarbonate (ZML).
(d) A functionally separated photosensitive layer laminated with a charge transport layer containing lubricant and a charge transport layer, (d) a charge generation layer containing an anthrone pigment and a polycarbonate resin on the charge transport layer (i-Laminated functionally separated photosensitive layers, etc.).

Examples of electron-donating compounds include poly-aromatic compounds such as anthracene, pyrene, phenanthrene, and cololyone, or indole, carba 7'-A, oxazole, inoxazole, thiazole, imidazole, etc.
Examples include compounds having nitrogen-containing complexes such as pyrazole, oxanoazole, pyrazoline, thiadiazole, and triazole, hydrazone compounds, and aromatic amine compounds.

Examples of electron-accepting compounds include aliphatic cyclic compounds, aromatic compounds, and heterocyclic compounds having electron-accepting compounds such as nitro groups, nitrone groups, and cyano groups.
Tetracyanoethylene, trinitrobenzene, dinitroacetophenone, trinitrobenzene, tetranitronaphthalene, terephthalonitrile, isophthalonitrile,
Examples include benzoyl cyanide, quinoline cyanide, cyanopyridine, nitroanthracene, sonitrofluorenone, trinitrofluorenone, tetranitrofluorenone, and tetracyanopyrene.

Electron-accepting compounds are generally not preferred due to their carcinogenicity and other harmful properties. When an electron-donating compound is used, the above-mentioned form (c) is used for negative charging, and the form (d) is used for positive charging.

The charge transport layer contains a charge transport material and a resin in a ratio of 5:1 to 1:2 (
The film thickness is 5 to 20 μm.
That's about it. In the above-mentioned form (C), the binder resin of the anthanthrone pigment includes polyester, polyvinylbenzal, polyvinyl butyral, polyvinylpyrrolidone, methylcellulose, polyacrylic acid esters, and cellulose ester 'Kttf' in addition to polycargonate 2.
x Used as appropriate.

Dispersion is done after mixing the pigment into the resin solution? - Conventional methods such as lumill, roll mill, sand mill, colloid mill, etc. can be used. The thickness of the charge generation layer is about o, oi to 1μ, preferably about 0.05 to 0.5μ. When the charge transport layer is formed on top, it is thicker, about 0.5 to 5 μm.

The ratio of pigment to resin is about 5:1 to 1:2.

〔effect〕

According to the present invention, the photosensitive layer containing an anthrone pigment and polycarbonate (Z) resin has high sensitivity, has few residual areas, and is stable without increasing bright area potential when charging and exposure are repeated. There is.

Also, is there polycarbonate on the surface? N) Since Z resin exists,
The surface has high hardness and excellent lubricity, making it less prone to scratches and improving mechanical durability. Furthermore, since the solution of polycarbonate Z resin has good storage stability as a coating liquid, it can improve productivity and contribute to quality stabilization.

Examples 1 to 6 A 60φ×260mm aluminum cylinder with a wall thickness of 0.5 #Im was prepared as a base.

Next, 4 parts of copolymerized nylon (trade name: CM8000, manufactured by Toshi ■) and 4 parts of type 8 nylon (trade name: Niratsukamite 5003, manufactured by Dainippon Ink Co., Ltd.) were bathed in 50 parts of methanol and 50 parts of lobetanol. Then, a 0.6 μm thick polyamide undercoat layer was formed on the conductive layer by dip coating.

Next, 10 parts of an anthrone pigment shown in Table 1 selected from the above-mentioned exemplified compounds, and 10 parts of polyvinyl butyral resin (trade name: Nisref 28M-2 manufactured by Fountain Chemical Co., Ltd.)
part was dispersed with 120 parts of siglohexanone in a sand mill for 10 hours. 30 parts of methyl ethyl ketone was added to the dispersion and coated on the undercoat layer to form a charge generation layer with a thickness of 0.15μ.
(weight average molecular weight: 120,000) was prepared and dissolved in 80 parts of monochlorobenzene together with 10 parts of a hydrazone compound having the following structural formula.

This was coated on the charge generation layer to form a charge transport layer with a thickness of 16 μm.

The photoreceptor produced in this manner was charged with -5,6 kV corona, and the photoreceptor was charged with -5,6 kV corona. Light, dry toner development, toner transfer to plain paper, urethane rubber blade (hard [70', pressure 5.
The electrophotographic properties were evaluated by attaching it to an electrophotographic copying machine having a cleaning process at 9 w/cm 2 and an angle of 20° with respect to the photoreceptor. When measuring the potential, the dark potential (V
Table 1 shows the potential (vL) when D) was -700 V and an exposure of 10 L/cm/sec was applied.

Comparative Examples 1 to 4 Photoreceptors were prepared in the same manner as in Example 1 and Ie1, except that organic pigments A to D below were used in place of the anthanthrone pigment in Example 1. The results of both characteristics are shown in Table 1.

Organic pigment compound A β-type copper phthalocyanine (Dainippon Ink Chemical Co., Ltd.)
made) ton
Q As mentioned above, all of the photoreceptors of Examples had higher sensitivity than those of Comparative Examples, and clear images without fog were obtained.

Example 7 A photoreceptor was prepared in the same manner as in Example 1, except that the anthoanthrone pigment of Exemplified Hardware Store 6 was used instead of the anthanthrone pigment of Exemplified Compound A1.

Comparative Examples 5 to 8 When forming the charge transport layer in Example 7, the following resins were used instead of the precarbonate Z resin.

These photoreceptors were evaluated using an electrophotographic copying machine having the same process as in Example 1 (however, the exposure amount was 7.2 lux·sec).

Evaluation: ・Initial VD/vL, and vDI after 10,000 prints
V. Further comparison was made by looking at the 10,000th image. The results are shown in Table 2.

As described above, the examples of the present invention using polycarbonate Z resin were excellent in terms of sensitivity, potential stability, and image quality in terms of durability after 10,000 cycles.

Comparative Example 9 In Example 7, when forming the charge transport layer, polycarbonate A resin (trade name:
When using L-12 Part 0 (manufactured by Teijin Kasei ■), the characteristics as a photoreceptor are vL, which is about O to experimental error.
It was a 10v change, so there was not much difference.

However, the viscosity of the coating liquid in which polycarbonate A resin and hydrazone compound were dissolved increased by 3 to 4 times after 24 hours, and after 48 hours it became viscous and lost fluidity, whereas polycarbonate Z In the case of the resin, there was no viscosity change at all even after 48 hours, and the coating solution was extremely stable.

Example 8 10 parts of polyvinyl carbazole (weight average molecular weight: 60,000) and 2 parts of m-terphenyl were dissolved in 80 parts of monochlorobenzene and 20 parts of methylene chloride. This was applied by dip coating onto the undercoat layer formed in the same manner as in Example 1 to provide a charge transport layer with a thickness of 18 μm.

Next, 10 parts of antoanthrone pigment from Illustrated Hardware Store 6 was mixed with polycarbate Z resin (manufactured by Konjin Kasei, weight average molecular [
The mixture was added to 250 parts of an 8% cyclohexanone solution (150,000) and dispersed in a sand mill for 10 hours.

This dispersion was spray coated onto the charge transport layer while rotating the drum. The electrophotographic photoreceptor 1, in which a charge generation layer having a thickness of 3 μm was formed in this way, was attached to the same electrophotographic copying machine as in Example 1 and evaluated. However, corona charging was set to +5.2 kV. The result is 1700 VD.
V, 7.5 Lux sec, vL when exposed to light is 14
(at 0 V), a good image could be obtained, and the same results as in Example 7 could be obtained.

On the other hand, even when the photoreceptor was made using each of the resins shown in Comparative Examples 5 to 8 instead of the polycarbonate z resin in Example 8, the evaluation of the characteristics was still the same as in Comparative Examples 5 to 8. .

Claims (4)

[Claims] (1) In an electrophotographic photoreceptor in which a photosensitive layer is provided on a conductive substrate, the photosensitive layer has the following general formula (1), ▲ mathematical formula, chemical formula, table, etc. ▼ (1) (in the formula, X is a halogen atom , nitro, cyano, acyl or carboxyl group, where n is a number from 0 to 4), and the following general formula (2), ▲Mathematical formula, chemical formula, table, etc. ▼(2) An electrophotographic photoreceptor characterized by containing a polycarbonate Z resin represented by (wherein m represents an integer of 50 to 5000) (2) The above photosensitive layer uses the above general formula (1) as a charge generating substance.
) An electrophotographic photoreceptor according to claim 1, which is formed by dispersing an anthrone pigment and a charge transport substance represented by the formula (2) in a polycarbonate Z resin represented by the above general formula (2). (3) A patent claim in which the photosensitive layer is a laminated type of a charge generation layer containing an anthrone pigment of the above general formula (1) and a charge transport layer containing a charge transport substance and a polycarbonate Z resin of the above general formula (2). Electrophotographic photoreceptor according to item 1 in the range of (4) The photosensitive layer is formed on the charge transport layer according to the general formula (1).
An electrophotographic photoreceptor according to claim 1, which is formed by laminating a charge generation layer containing an anthrone pigment and a polycarbonate Z resin of general formula (2).