JPS62100757A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To obtain a sensitive body having high sensitivity by forming laminated layers comprising a charge generating layer contg. phthalocyanine photoconductive pigment and brominated poly-N-vinyl carbazole and a charge transfer layer contg. a hydrazone compd. on an electroconductive base body. CONSTITUTION:A charge generating layer is formed by coating phthalocyanine photoconductive pigment and a brominated poly-N-vinyl carbazole or a mixture contg. appropriate binder resin dispersed in addition to the above described compds. on an electroconductive base body. The amt. of said brominated poly-N- vinyl carbazole to be used is 0.1-5, pref. 0.5-1pts.wt. per 1pt.wt. phthalocyanine photoconductive pigment. The charge transfer layer is formed by coating coating liquid contg. a charge transfer agent and binder resin dissolved therein wherein said charge transfer agent is a hydrazone compd. The amt. of the binder resin to be used is pref. <=50wt% basing on the amt. of the charge transfer layer. Any electroconductive material known in the prior art may be used as the material for the electroconductive base body.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to electrophotographic photoreceptors containing organic photoconductive materials.

2. Description of the Related Art Conventionally, photoreceptors made of inorganic conductive materials such as selenium, selenium-tellurium alloy, cadmium sulfide, and zinc oxide have been widely used as electrophotographic photoreceptors. In recent years, research has been progressing on organic photoconductive substances that are easy to synthesize and have the ability to select compounds that exhibit photoconductivity in an appropriate wavelength range.

An electrophotographic photoreceptor using an organic photoconductive substance in the photosensitive layer is
It has advantages such as easy film formation, high flexibility and freedom of design, low cost and non-polluting properties, making it possible to use electrophotography that is not possible with photoreceptors made of concentrated photoconductive materials. process (eg, using a belt-shaped photoreceptor). Among these, in order to improve sensitivity and photoreceptor life, a laminated electrophotographic photoreceptor was proposed in which the photosensitive layer was formed by separating the functions into a charge generation layer and a charge transport layer. Active research is being carried out to improve and develop sensitization methods. (For example, the Proceedings of the 16th Electrophotographic Society Seminar) Problems to be Solved by the Invention However, the above-mentioned organic photoreceptors have not yet fully satisfied the various requirements for electrophotographic photoreceptors. is the current situation. Therefore, it is desired to develop a highly sensitive electrophotographic photoreceptor that fully satisfies the characteristics required for an electrophotographic photoreceptor by taking advantage of the advantages of organic conductive materials.

Means for Solving the Problems In view of the above problems, the present invention provides a charge generation layer containing a phthalocyanine photoconductive pigment and a brominated poly-N-vinylcarbazole, and a charge transport layer containing a hydrazone compound. A highly sensitive electrophotographic photoreceptor is provided by laminating these on a conductive support.

action The electrophotographic photoreceptor of the present invention will be explained in detail below.

The charge generation layer of the electrophotographic photoreceptor of the present invention is prepared by dispersing a phthalocyanine-based photoconductive pigment and brominated poly-N-vinyl Rubazole or by adding an appropriate binder resin, and dispersing this on a conductive support. Obtained by coating. Specifically, the phthalocyanine photoconductive pigment is
Epsilon type copper phthalocyanine, α type copper phthalocyanine, β type copper phthalocyanine, other metal phthalocyanines, metal-free phthalocyanines, etc. can be used. Brominated poly-N-vinylcarbazole is one in which 0.5 to 2 bromines are substituted for one carbazole ring,
Poly-N-vinylcarbazole in a mixed solvent of chlorobenzene-benzene in the presence of a small amount of benzoyl peroxide,
It can be easily synthesized by treating with an equivalent amount of N-bromsucciniside, heating, and then pouring into methanol.

In addition, brominated poly-N-vinylcarbazone is used in an amount of 0.1 to 5 parts by weight per 1 part by weight of the phthalocyanine photoconductive pigment.
It is used in an amount of 0.5 to 1 part by weight, preferably 0.5 to 1 part by weight. Furthermore, although brominated poly-N-vinylcarbazole alone has film-forming properties, it is necessary to use brominated poly-N-vinylcarbazole for the purposes of improving adhesion between the charge generation layer and other layers, improving uniformity of the coating film, and adjusting fluidity during coating.
A binder resin can be used if necessary. Specifically, polyvinyl butyral, polyvinyl acetate 1.
Examples include polyvinyl chloride, polycarbonate, acrylic resin, methacrylic resin, and copolymers of these resins. The amount of binder resin used is preferably 50% by weight or less of the weight of the charge generation layer. Also, brominated poly-N
- Solvents that dissolve vinyl carbazole and binder resin are limited to brominated poly-N-vinyl carbazole, but specifically include chloroform, methylene chloride, ethylene dichloride, halogenated hydrocarbons, chlorobenzene, etc. Halogenated aromatics, dioxane, cyclic ethers such as tetrahydrofuran, etc. can be used. The thus dispersed coating solution is applied by a normal coating method and dried by heating to form a charge generation layer with a thickness of several μm, preferably 0.2 to 2 μm. It is better.

The charge transport layer of the electrophotographic photoreceptor of the present invention can be obtained by coating the charge generation layer with a coating liquid in which a charge transport agent and a binder resin are dissolved.

The charge transporting agent is a hydrazone compound, and specific examples thereof include those having the structural formula shown below, but are not limited to these compounds (and it is also possible to mix two or more types).

Cl1-Ph C, HS C! II S Further, the binder resin used when forming the charge transport layer is a well-known polymer, specifically, an acrylic resin,
Examples include methacrylic resin, polyester, polystyrene, polycarbonate, polysulfone, polyvinyl butyral, epoxy resin, urethane resin, and phenoxy resin. The amount of binder resin used is 5% of the weight of the charge transport layer.
It is preferably 0% by weight or less. Furthermore, the solvent for dissolving the charge transport agent and binder resin and preparing the coating liquid is:
They can be selected and used depending on the composition of the charge generation layer, the charge transport agent, and the binder resin. Specifically, alcohols such as methanol, ethanol and isopropyl alcohol, ethers such as tetrahydrofuran, dioxane and ethylene glycol monomethyl ether, Kents such as methyl ethyl ketone and cyclohexanone, esters such as methyl acetate and ethyl acetate, N, N -Amides such as dimethylformamide, aromatics such as toluene, xylene, and chlorobenzene, and halogenated hydrocarbons such as chloroform, methylene chloride, and ethylene dichloride can be used. The coating solution prepared in this way is applied by a normal coating method, heated and dried, and
The charge transport layer is formed to have a thickness of several tens of μm, preferably 5 to 25 μm.

The conductive support used in the electrophotographic photoreceptor of the present invention is
Any material that has conventionally known conductivity may be used, such as metal plates and metal drums made of aluminum or aluminum alloys, plates made of metal oxides such as tin oxide or indium oxide, or metals and metal oxides thereof. These include various plastic films, papers, etc. that have been treated to be conductive by adhering them by vacuum evaporation, sputtering, laminating, coating, etc.

Furthermore, in the charge generation layer and charge transport layer constituting the electrophotographic photoreceptor of the present invention, 0-terphenyl, epoxy compounds, Softeners such as phthalate esters, maleate esters, and chlorinated paraffins may also be added. Also,
Like ordinary electrophotographic photoreceptors, casein, polyvinyl alcohol, polyvinyl acetate,
An adhesive layer or barrier layer such as polyvinyl butyral may be provided.

The electrophotographic photoreceptor of the present invention, which is formed by laminating the charge generation layer and the charge transport layer on the conductive support in this way,
A charge generation layer and a charge transport layer may be laminated in this order on an electrosensitive support, or a charge transport layer and a charge generation layer may be laminated in this order on a conductive support. The former case has sensitivity when charged negatively, and the latter case has sensitivity when charged positively, but the former is more desirable in terms of surface film strength and durability.

EXAMPLES The present invention will be explained below using examples, but the present invention is not limited to the combinations shown in the examples below.

(Example 1) Brominated poly-N-vinylcarbazole 1ffiffi
0.05 parts by weight of vinyl chloride and vinyl acetate copolymer (trade name VMCH manufactured by Union Carbide) were dissolved in 100 parts by weight of ethylene dichloride, and ε-type copper phthalocyanine (
Toyo Ink Part name: Liophoton-ERPC)
2 parts by weight were added and dispersed. This dispersion was applied onto an aluminum vapor-deposited polyethylene terephthalate film (product name: Metal Me, manufactured by Toyo Metallizing ■) using a wire bar coater, and dried at 80°C for 1 hour to give a film thickness of 0.3μ.
A charge generation layer of m was formed.

Next, 1 part by weight of a hydrazone compound having the structural formula and 1 part by weight of an acrylic resin (trade name BR-50 manufactured by Mitsubishi Rayon ■) were dissolved in 4 parts by weight of toluene. This liquid was applied onto the charge generation layer using a blade and dried at 80° C. for 1 hour to form a charge transport layer having a thickness of 18 μm.

The surface potential (■) when the thus obtained laminated electrophotographic photoreceptor was charged at -5.5 KV using an electrostatic copying paper tester (EPA-8100 manufactured by Kawaguchi Electric Seisakusho ■). (
V), surface potential V+ when left in the dark for 1 second
(V), the exposure amount E +zz (lux -5ec) required for the surface potential to attenuate to 1/2 Vl (V) when exposed to 51ux white light, and the surface potential VR & (V) after 6 seconds of exposure. did. The measurement results are shown in Table 1.

(Example 2) A charge generation layer was formed in the same manner as in Example 1, and 9.8 parts by weight of a hydrazone compound having the structural formula % and polycarbonate (
1 part by weight of Mafrohol (trade name, manufactured by Bayer AG) was dissolved in 10 parts by weight of chlorobenzene. This solution was applied onto the charge generation layer with a blade and dried at 80°C for 1 hour to form a film with a thickness of 18.
A charge transport layer of .mu.m was formed.

The thus obtained laminated electrophotographic photoreceptor was measured in the same manner as in Example 1 using an electrostatic copying paper tester, and the results are shown in Table 2.

(Example 3) For a comparative experiment, a sample was prepared with a composition in which brominated poly-N-vinylcarbazole was not added.

Butyral resin (Product name: Slek BH manufactured by Block Chemical II)
-3) 1 part by weight was dissolved in 40 parts by weight of ethylene glycol monomethyl ether, and 2 parts by weight of ε-type copper phthalocyanine was added and dispersed. A charge generation layer was formed using this dispersion in the same manner as in Example 1. Further, the charge transport layer was formed using the same composition and method as in Example 1.

The thus obtained laminated electrophotographic photoreceptor was measured in the same manner as in Example 1 using an electrostatic copying paper tester, and the results are shown in Table 1.

(Example 4) For a comparative experiment, a sample was prepared with a composition in which brominated poly-N-vinylcarbazole was not added.

A charge generation layer was formed in the same manner as in Example 3, and a charge transport layer was formed in the same manner as in Example 2.

The thus obtained laminated electrophotographic photoreceptor was measured in the same manner as in Example 1 using an electrostatic copying paper tester, and the results are shown in Table 2.

Table 1 Table 2 Effects of the Invention The electrophotographic photoreceptor of the present invention has been described in detail above. A charge generating layer containing a hydrazone compound and a charge transporting layer containing a hydrazone compound are laminated on a conductive support to provide a high-temperature layer. Further, it is possible to obtain an electrophotographic photoreceptor using an organic photoconductive substance that has good charging properties, low residual potential, and satisfies the characteristics required for electrophotography.

Claims (2)

[Claims] (1) Phthalocyanine photoconductive pigment and brominated poly-
An electrophotographic photoreceptor characterized in that it is formed by laminating a charge generation layer containing N-vinylcarbazole and a charge transport layer containing a hydrazone compound on a conductive support. (2) An electrophotographic photograph according to claim 1, wherein the brominated poly-N-vinylcarbazole is substituted with 0.5 to 2 bromine per carbazole ring. Photoreceptor.