JPH01166052A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To increase selectivity of a polymer to be used in the title electrophotographic sensitive body for hydrazone and stilbene compd. and to make a design of the sensitive body easier, by incorporating a specified hydrazone compd. and/or a stilbene compd., together with an aromatic ketone and/or an aromatic ester in an electrophotographic sensitive body compsn. CONSTITUTION:The title electrophotographic sensitive body contains a hydrazone compd. expressed by formula I and/or a stilbene compd. expressed by formula II, together with an aromatic ketone expressed by formula III and/or an aromatic ester expressed by formula IV. Melting points of the compds. expressed by formulas III and IV are pref. <=100 deg.C. When a charge transfer layer is formed from a donative charge transfer material such as hydrazone, etc., and a polymer having an acceptive carbonyl group such as polyacrylate, etc., foots of an absorption spectrum are extended by the interaction to a long wavelength side. Similar phenomenon is caused when a polymer other than polymers having acceptive carbonyl groups is used. Thus, a range of selection for polymers is widened when a hydrazone compd. or a stilbene compd. is used as a charge transfer material, thus a superior electrophotographic sensitive body is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to an electrophotographic photoreceptor used in copying machines, laser printers, and the like.

(Prior art) In conventional electrophotographic technology, the photosensitive layer of an electrophotographic photoreceptor uses inorganic materials such as selenium and cadmium sulfide.

Although zinc oxide and the like have been widely put into practical use, in recent years, research has been increasingly conducted on the use of organic photoconductive materials as electrophotographic photoreceptors.

Today, organic photoconductive materials are replacing inorganic photoconductive materials. This is based on the fact that, although it has advantages in terms of basic electrophotographic characteristics such as photosensitivity residual potential, it also includes various disadvantages.

Many of the disadvantages are, for example, manufacturing difficulties, pollution of the raw materials, or problems with toxicity during sanitary use. In the case of selenium, in addition to the difficult manufacturing conditions for the selenium vapor-deposited film, it has poor mechanical strength, and selenium tends to crystallize on the surface of the photoreceptor. In the case of cadmium sulfide, it is sensitive to temperature and humidity, and there is a problem of pollution caused by cadmium compounds. Furthermore, in the case of zinc oxide, there is a problem with the dispersion stability when dispersing zinc oxide particles in a resin, and there are problems such as fatal property deterioration due to temperature and humidity.

On the other hand, compared to inorganic photoconductive materials, it is often possible to use resin as a binder for organic photoconductive materials.
It is easy to manufacture and inexpensive in either solution or dispersion form. In addition, the photosensitive layer has excellent flexibility, it is easy to obtain a photosensitive member with various functions depending on the intended use of the photosensitive member, and the photosensitive member can be designed in a variety of ways.

In view of these points, research and development of electrophotographic photoreceptors using organic photoconductors has recently become more active, and electrophotographic photoreceptors using various organic photoconductors have been proposed and industrially implemented. Some have even been put into practical use.

However, although various electrophotographic photoreceptors have been proposed, there are still not enough photoreceptors that satisfy the basic characteristics required for a photoreceptor, such as mechanical strength, durability, and storage stability. It has not been done.

Particularly in connection with the present invention, electron-accepting compounds have long been known as additives used as sensitizers.
A material that interacts with a charge generating material or a charge transporting material. -An example of this is when trinitrofluorenone is added to polyvinylcarbazole. However, in recent years, there are no standards for selecting sensitizers when using resin-dispersed compounds such as hydrazone and stilbene, which have been discovered as excellent charge transport materials, and no excellent ones have yet been found. be.

The performance of a charge transport material is determined by its combination with a specific polymer. For example, for hydrazone and stilbene, polymers having an acceptor carbonyl group such as polycarbonate, polyarylate, and polyester can be used. When a charge transport layer is formed with these polymers and a donor charge transport material such as hydrazone, the interaction generally causes the base of the absorption spectrum to expand toward longer wavelengths in the visible spectrum.

As described above, a specific relationship is required between the charge transport material and the polymer forming the charge transport layer, and there is a problem in that the range of polymer selection is narrow. This ultimately leads to problems such as narrowing the selection range of charge generating materials to be used and making it difficult to change manufacturing conditions, etc., which is a major obstacle in obtaining an electrophotographic photoreceptor with desired characteristics. It became.

(Problems to be Solved by the Invention) As described above, the selection range of polymers used for charge transporting materials is narrow, which poses a major problem in designing electrophotographic photoreceptors.

The present invention has been made in consideration of the above points, and has been made for the purpose of accomplishing the following.

[Structure of the invention]

(Means and effects for solving the problems) That is, the present invention provides a hydrazone compound represented by formula-(1) and/or a stilbene compound represented by formula-■; an aromatic ketone represented by formula-(3); An electrophotographic photoreceptor characterized by containing an aromatic ester represented by the following formula:

Formula 1 ■ Formula -■ The melting point of formula 1 (■, ni) is preferably 100°C or lower. ) As mentioned above, when a charge transport layer is formed with a donor charge transport material such as hydrazone and a polymer having an acceptor carbonyl group such as polyarylate, the interaction causes the absorption spectrum to shift toward the longer wavelength side. spread. A similar phenomenon occurs when polymers other than polymers having acceptor carbonyl groups are used, such as polystyrene, butyral resin, styrene-butadiene copolymer, vinyl acetal resin, silicone resin, polyphenylene-oxide resin, phenol resin, etc. The present invention has discovered an additive that exhibits the following effects.

As an additive, Me　OOC+COOMe etc.

The photosensitive layer of the present invention may have a single layer or a laminated structure. It can be applied to any type of electrophotographic photoreceptor, such as a functionally separated photoreceptor comprising a charge transport layer.

As charge generating materials, ■ type phthalocyanine, X type lid [
Metal-free phthalocyanines such as vanadyl phthalocyanine and titanyl phthalocyanine, metal-free phthalocyanines such as vanadyl phthalocyanine and titanyl phthalocyanine, bisazo pigments, monoazo pigments, non-metallic pigments, quinaxodone pigments, anthraquinone pigments, etc. can be used.

The conductive support used in the present invention may be any support that is normally used as a conductive support for electrophotographic photoreceptors, and is not particularly limited. Examples of such supports include, for example, metal materials such as brass, aluminum, gold, and silver; the surface of said metal is coated with a thin film of plastic; metal-coated paper, metal-coated plastic sheets, or aluminum iodide, iodine Copper.

Examples include glass coated with a conductive layer such as chromium oxide or tin oxide. These are used as cylindrical sheet thin plates having appropriate thickness, hardness and flexibility, and either the support itself is electrically conductive or the surface thereof is electrically conductive.
It is preferable that the material has sufficient strength when handled.

(Example) The present invention will be explained in detail below.

■ Type phthalocyanine (manufactured by Toyo Ink) is mixed with butyral (B).
) l-1, manufactured by Tsukimizu Kagaku Co., Ltd.) A coating solution that was dispersed in a 2 wt% cyclohexanone solution using a ball mill for 3 hours was coated with Dip 94.
It was applied to an aluminum plate at a thickness of about 0.2 mm using a tar to form a charge generation layer. Next, using 9-ethylcarbazole-3-carboxaldehydemethylphenylhydrazone (9-ethylcarbazole-3-carboxaldehydemethylphenylhydrazone) as the hydrazone and N,N-diethylaminostilbene 0 as the stilbene, equimolar mixtures with the compounds shown in Table 1 were mixed with various binders. The mixture was coated onto the charge generation layer to a thickness of about 201 JIR to form a charge transport layer.

The sample prepared in this way was
Corona discharge -6KV using P-428 (manufactured by Kawaguchi Electric)
Initial charging potential Vo (V), dark potential retention rate D5 (%) after 5 seconds with respect to Vo, tungsten light (151u
The half-reduced exposure amount for X ) is E H (lux ” 5e
c) Residual potential VR (%) was measured. The results are shown in Table 2.

The compounds listed in Table 1 are white in the solid state, but when mixed with hydrazone and stilbene in the solution state and dried, they turn yellow and produce new absorption on the longer wavelength side of the electronic spectrum.

Furthermore, as clearly seen from Table 2, even when polystyrene is made into a polymer by adding additives, it is possible to realize a cost reduction of Ey2° that is equal to or higher than that of polyarylate.

〔Effect of the invention〕

This has been explained above. As described above, according to the present invention, when hydrazone and methylbenne compounds are used as charge transport materials, the selection range of polymers is expanded, and an excellent electrophotographic photoreceptor can be obtained.

Agent: Patent Attorney Noriyuki Chika Same as Matsuyama% fan

Claims (2)

[Claims] (1) A hydrazone compound shown in formula-(1) and/or a stilbene compound shown in formula-(2); an aromatic ketone shown in formula-(3) and/or an aromatic ester shown in formula-(4); An electrophotographic photoreceptor characterized by containing. Formula-(1) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ [R^1, R^2; Phenyl group which may have substituents,
Alkyl group R^3; The following substituents (Et: ethyl group, Me: methyl group) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ Formula - (2) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ [R^8 ; H, alkoxy group, alkyl group R^9; H, alkoxy group, phenyl group having a substituent R
^1^0; Methyl group, ethyl group, phenyl group] Formula - (3
) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ [R^4; H, electron-withdrawing substituent R^5; phenyl group, alkyl group, aralkyl group that may have a substituent] Formula - (4) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ [R^6; H, MeOCO-, EtOCO-▲There are mathematical formulas, chemical formulas, tables, etc.▼ R^7; Methyl group, ethyl group] (2) The melting point of the substance shown in the above formula-(3) and (4) is 10
The electrophotographic photoreceptor according to claim 1, characterized in that the temperature is 0° C. or lower.