JPS63174053A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To improve the electrification and the sensitivity of the positive charge photosensitive body by incorporating a specific triphenylmethane and a hydrazone compd. to a photosensitive layer used a phthalocyanine material. CONSTITUTION:The triphenylmethane (B) shown by formula I and the hydrazone compd. (C) shown by formula II are incorporated to the photosensitive layer used the phthalocyanine type electric charge generating material (A). In formula I, R1-R4 are each H atom or 1-8C alkyl group, etc., R5 and R6 are each H atom or OH group, etc., R7 is H atom or alkoxy group, etc. In formula II, R1 is H atom, a (substd.)alkyl group, etc., R2 is a (substd.)aryl or aralkyl group, etc., R3 is a (substd.)aryl or alkyl group, etc., R4 is a (substd.)heterocyclic ring group. And, the titled photosensitive layer can be formed by incorporating the components B and C to a dispersion of the component A (for example, epsilon-copper phthalocyanine) or by incorporating the component A and at least the component B to an electric charge generating layer, and at least the component C to an electric charge transferring layer, respectively.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to an electrophotographic photoreceptor, and more specifically to a positively charged electrophotographic photoreceptor that is exposed to light after being positively charged by an anode corona discharge. Regarding.

(Prior art) An electrophotographic photoreceptor is a positively charged type using a corona-charged anode.
There are two types of negatively charged types.

Many negatively charged photoreceptors have been developed in which a charge generation layer and a charge transport layer are sequentially laminated on a conductive support, and some are known to have excellent initial characteristics. However, cathode corona discharge tends to generate ozone, and the deterioration of the photoreceptor due to the oxidizing effect of this ozone and the contamination of the copying environment due to ozone have become problems, and it is desirable to develop a positively charged electrophotographic photoreceptor with excellent characteristics. It is rare.

(Problems to be Solved by the Invention) Generally, the photoconductive process of an electrophotographic photoreceptor consists of a photocharge generation process and a charge transport process.

Conventionally known electrophotographic positively charged photoreceptors are the two mentioned above.
These processes can be roughly divided into those in which each process is performed using one type of substance, and those in which each process is performed using different types of substances.

As such electrophotographic photoreceptors, there are the following three types of functionally separated photoreceptors in which charge generation and charge transport are performed using different materials.

■Those with a dispersed structure in which a charge generation material and charge transport material are dispersed in one layer■Those with a structure in which a charge transport layer and a charge generation layer are laminated in order on a conductive support■On a conductive support A structure in which a charge generation layer and a charge transport layer are laminated in order.
Both have the problem of low sensitivity.

The type (■) has not been studied much because there is no material with excellent charge transport.

Further, in order to improve the sensitivity of photoreceptors of types (1) and (3), studies are being conducted to increase the concentration of charge-generating materials or to add charge-transporting materials.

Such systems have problems such as low charging ability due to high dark decay and low charging speed.

The present invention has been made with attention to this point, and provides a positively charged electrophotographic photoreceptor of a type that is exposed to light after being positively charged by an anode corona discharge without deterioration of the photoreceptor due to ozone generation or ozone oxidation. The purpose is to

[Structure of the invention]

(Means and effects for solving the problems) The electrophotographic photoreceptor of the present invention uses triphenylmethane represented by the following structural formula <r> and the following structural formula ( The aryl group in the above-mentioned formula, which is characterized by containing a hydrazone compound represented by U), includes a phenyl group, a naphthyl group, an anthracene group, a phenanthrene group, a tetralin group, an azulene group, a biphenylene group, an acenaphthylene group, acenaphthene group, fluorene group, fluoranthene group,
There are triphenylene groups, pyrene groups, chrysene groups, naphthacene groups, bicene groups, perylene groups, benzopyrene groups, rubycene groups, coronene groups, obalene groups, etc. Substituents for these aryl groups include di-substituted amino groups (e.g. Dimethylamino group, diethylamino group, dibutylulamino group, methylbutylamino group, methylbutylamino group, dialkylamino group such as siamylamino group, dialkylamino group such as dibenzylamino group, diarylamino group, diphenylamino group, ditolylamino group group, diarylamino group such as diaryamino group), alkoxyl group (e.g. methoxyl group, ethoxyl group, propoxyl group, butoxyl group), aryloxy group (e.g. phenoxy group, naphthoxy group), alkyl group, nitro group, cyano group, etc. Examples include hydroxyl group, acetyl group, and halogen atom.

In addition, the heterocyclic group in the above formula includes an indole ring,
There are monovalent groups in which one hydrogen atom is removed from a carbazole ring, benzofuran ring, oxadiazole ring, thiazole ring, thiadiazole ring, pyrazoline ring, imidazole ring, oxazole ring, etc. These substituents include the above-mentioned aryl Examples include monovalent groups that are the same as substituents of the group.

In addition, examples of the aralkyl group in the above formula include benzyl group, phenethyl group, phenylpropyl group, phenylbutyl group, naphthylmethyl group, naphthylethyl group, etc. Substituents for these aralkyl groups include the above-mentioned aryl group. Examples include the same monovalent group as the substituent.

Furthermore, the alkyl group in the above formula includes a methyl group,
Examples include ethyl, butyl, and propyl groups, and examples of substituents for these alkyl groups include halogen atoms.

The triphenylmethane and hydrazone compounds used in the present invention have hole transport ability and are effective in the above-mentioned photoreceptors of type (1) and (2).

When used as a single layer type (ii), it can be obtained by containing triphenylmethane and a hydrazone compound in a photosensitive layer formed by dispersing a phthalocyanine compound in a binder resin.

The amount of triphenylmethane added is preferably 0.1 to 30 times the molar ratio of the phthalocyanine compound, and more preferably 0.2 to 20 times. The amount of hydrazone added is 0.02 to 5 times the molar ratio of the phthalocimeshi compound.
It is preferably 0 times, and more preferably 0.1 to 30 times. If the amount of triphenylmethane and hydrazone added is too large, crystallization may occur and the sensitivity may decrease. Moreover, if there is little hydrazone, the sensitivity will be low, and if there is little triphenylmethane, the charging ability will be insufficient.

Triphenylmethane and hydrazone are added after or at the time of dispersing the phthalocyanine in the binder resin solution, and the photosensitive layer is formed by coating the solution on a conductive support.

When using hydrazone and triphenylmethane in the multilayer type (2), they can be obtained by adding them to the charge generation layer and/or the charge transport layer, but a particularly effective combination is to add hydrazone to the charge transport layer and to the charge generation layer. In this case, triphenylmethane and hydrazone were used.

In this case again. A hydrazone other than the one represented by structural formula (II) may be used in the charge transport layer.

Note that the amounts of triphenylmethane and hydrazone added to the charge generation layer may be the same as in the case of using a single layer type.

The binder resin in the present invention is, for example, polyester.

Examples include acrylic resin, polycarbonate, polyarylate, polyester polycarbonate, polystyrene, polyvinylidene chloride, phenoxy resin, butyral resin, and the like.

The conductive support used in the present invention may be anything that is normally used as a conductive support for electrophotographic photoreceptors, and is not particularly limited. As a support, for example, metal materials such as brass, aluminum, gold, silver; metal-coated paper, metal-coated plastic sheets or coated with a conductive layer such as aluminum iodide, steel iodide, chromium oxide or tin oxide can be used. Glass is an example.

(Example) Examples 1 to 6 To 500 g of 5% polyarylate (trade name U-100) trichloroethane solution Je was added 25 g of phthalon "Ayu" shown in Table 1 and dispersed in a ball mill to prepare a paint. Table 1 shows phenylmethane.
Apply after adding to the composition shown in .

Dry 15. A photosensitive layer was formed.゛Charging characteristics of the electrophotographic photoreceptor prepared in this way were determined using Kawaguchi Electric Paper Analyzer SP-428.
Light sensitivity was evaluated.

Further, a photoreceptor to which hydrazone was not added was prepared as Comparative Example 1, and a photoreceptor to which triphenylmethane was not added was prepared as Comparative Example 2, and evaluated in the same manner.

As a result, the electrophotographic photoreceptor according to the present invention had good sensitivity and charging ability, whereas Comparative Example 1 had low sensitivity and Comparative Example 2 had low charging ability.

Examples 7 to 12 A solution prepared by dissolving 5 g of the hydrazone compound shown in Table 2 and 5 g of polyester (trade name Vylon 200) in 45 g of cyclohexanone was applied onto aluminum mylar and dried to a thickness of 6 Is.
A charge transport layer was formed.

On this [\rI transport layer, 1.5 g of triphenylmethane and 1.5 g of the phthalocyanine compound shown in Table 2 were added to 3% dichloroethane of polycarbonate (trade name 8.2000).
A paint dispersed in 100 g of the solution was applied and dried to form a 6- charge generation layer.

In addition, a photoreceptor was prepared in which triphenylmethane was not added to the charge generation layer as Comparative Example 3, and a photoreceptor was prepared in which hydrazone was added instead of triphenylmethane as Comparative Example 4, and the characteristics were the same as in Examples 1 to 6. We conducted an evaluation.

As a result, the photoreceptor of the present invention had good sensitivity and charging ability, whereas Comparative Example 3 had low sensitivity, and Comparative Example 4 had a low charging ability.

〔Effect of the invention〕

As is clear from the results of the Examples above, the electrophotographic photoreceptor of the present invention has excellent charging ability and sensitivity, and is positively charged, so it is stable and less affected by ozone.

Claims (3)

[Claims] (1) In an electrophotographic photoreceptor using a phthalocyanine-based photoconductive material as a charge-generating material, the following structural formula (I) is used.
Electrophotographic photoreceptor structural formula (I) characterized by containing triphenylmethane represented by and a hydrazone compound represented by the following structural formula (II) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ [However, in the formula, R_1_ ~_4 is H, an alkyl group having 1 to 8 carbon atoms, an aralkyl group, an aryl group R_5_ to _6 are H, OH, a halogen alkyl group having 1 to 8 carbon atoms, or an amino group that may be substituted with an alkoxy group, aryloxy Group R_7 is H, alkyl group having 1 to 8 carbon atoms, alkoxy group, aryl group, aralkyl group Structural formula (II) ▲ Numerical formula, chemical formula, table, etc. are available ▼ However, in the formula, R_1 is H, optionally substituted alkyl base,
Aryl group, aralkyl group R_2 is an optionally substituted aryl group, aralkyl group,
Heterocyclic group R_3 is an optionally substituted aryl group, alkyl group, aralkyl group, heterocyclic group R_4 is an optionally substituted heterocyclic group (2) The electronic device according to claim 1, wherein the triphenylmethane and hydrazone compound are contained in a photosensitive layer formed by dispersing a phthalocyanine-based photoconductive material in a binder. Photographic photoreceptor. (3) A charge transport layer and a charge generation layer are laminated on a conductive support, the charge generation layer contains phthalocyanine and at least the triphenylmethane, and the charge transport layer contains at least a hydrazone compound. Range 1
The electrophotographic photoreceptor described in .