JPH0511468A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To obtain the photosensitive body high in mobility, small in residual potential and dark decay, and good in repetition stability by forming an electric charge transfer layer containing a specified hydrazone compound. CONSTITUTION:The charge transfer layer is formed by incorporating a charge transfer material and a charge generating material in it and this charge transfer material is the hydrazone compound represented by formula I each of R<1> and R<9>-R<11> is H, alkyl, or the like and each of R<2>-R<8> is H, halogen, or the like. This hydrazone compound has a part of its carbazole ring reduced, so lowered in crystallinity, thus permitting this compound alone to form a ring, therefore, the charge transfer material to be formed into a film in high concentration, and the electrophoto-graphic sensitive body high in sensitivity to be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic photosensitive member using a low molecular charge transfer material having a hydrazono group, and more specifically, in an electrophotographic photosensitive member comprising a charge generation layer and a charge transfer layer, charge transfer The present invention relates to an electrophotographic photoreceptor, wherein the layer is composed of a hydrazone compound represented by the general formula (I).

[0002]

2. Description of the Related Art Inorganic substances such as selenium (Se), cadmium sulfide (CdS), zinc oxide (ZnO), and amorphous silicon (a-Si) are used as photoconductive materials for photoconductors used in electrophotography. .. These inorganic photoconductors have many advantages, but at the same time, they have various drawbacks such as harmfulness and high cost. For this reason, in recent years, many organic photoconductors using organic substances without these defects have been proposed and put to practical use.

As the structure of these photoconductors, a material that generates a charge carrier (hereinafter, referred to as a charge generation material) and a generated charge carrier are received and moved (hereinafter, charge transfer). (Referred to as a material) and a single-layer structure in which charge generation and charge transfer are performed in the same layer. A multilayer structure is a material selection method. It is widely used because of its wide width and high sensitivity.

As the charge transfer material, there are a case where a high molecular weight photoconductive compound such as polyvinyl calsol is used and a case where a low molecular weight photoconductive compound is dispersed and dissolved in a binder polymer. A polymer photoconductive compound alone has insufficient film properties and adhesiveness, and plasticizers, binders, etc. are added to improve these drawbacks, but this causes a decrease in sensitivity and an increase in residual potential. However, problems such as the above are likely to occur and practical application was difficult. On the other hand, the low-molecular weight photoconductive compound can easily eliminate the defects of film formability and adhesiveness by properly selecting the binder, but it cannot be said to be sufficient in terms of sensitivity.

[0005]

In recent years, with the development of non-impact printing technology, research and development of electrophotographic printers using a laser light source have been actively conducted.
In these devices, miniaturization of device size and speeding up are being promoted, and high sensitivity and high mobility of photoconductor materials are also desired, but conventional charge materials are used for the charge transfer layer. However, the electrophotographic photosensitive member has a large residual potential and a large dark decay and has not yet obtained sufficient sensitivity.

The present invention has been made in view of the above-mentioned conventional circumstances, and provides an electrophotographic photosensitive member which has a high mobility, a small residual potential and a small dark decay, and exhibits good repetitive stability. The purpose is to

[0007]

DISCLOSURE OF THE INVENTION The inventors of the present invention continued research in view of such a conventional situation, and as a result, the general formula (I) was obtained.
It was found that by forming a charge transfer layer with the hydrazone compound shown in, high mobility, small residual potential and dark decay, and good cyclic stability are exhibited.

That is, according to the present invention, in an electrophotographic photoreceptor containing a charge generating material and a charge transfer material, the charge transfer layer is formed of a hydrazone compound characterized by having a structural formula represented by the general formula (I). An electrophotographic photosensitive member characterized by the above.

[0009]

[Chemical 1]

Further, the production thereof can be obtained by reacting the compound represented by the general formula (II) with the hydrazone compound represented by the general formula (III).

[0011]

[Chemical 2]

[0012]

[Chemical 3]

The hydrazone compound according to the present invention can be produced, for example, as follows. That is, N-alkylaniline is nitrosated with nitrous acid and reduced to obtain 1-phenyl-1-alkylhydrazine. This hydrazine is condensed with cyclohexanone to obtain a carbazole derivative. The hydrazine compound of the present invention can be obtained by reducing this, introducing an aldehyde group by the Vilsmeier reaction, and then subjecting it to a condensation reaction with a hydrazine compound.

The above-mentioned carbazole derivative can also be obtained in one step by reacting N-nitroso-N-alkylaniline and cyclohexanone in the presence of zinc in an acetic acid solvent.

In the present invention, the hydrazone compound represented by the general formula (I) can be used in a solution of tetrahydrofuran, chloroform, methylene chloride or the like, and a hard film can be produced by casting the solution dissolved in these. Therefore, it is useful as a charge transfer material for an electrophotographic photoreceptor.

The electrophotographic photoreceptor of the present invention is preferably one in which an undercoat layer, a charge generation layer and a charge transfer layer are laminated in this order on a conductive substrate, but the undercoat layer, the charge transfer layer and the charge generation layer are preferred. May be laminated in this order, or may be one in which the charge generating material and the charge transfer material are dispersed and coated with an appropriate resin on the undercoat layer. The undercoat layer may be omitted if necessary. According to the invention,
By coating the substrate with the hydrazone compound, it is possible to obtain a charge transfer layer having a high charge mobility, a small residual potential and a small dark decay, and exhibiting good repeated stability.

The coating is a spin coater, applicator, spray coater, bar coater, dip coater,
A doctor blade, a roller coater, a curtain coater, or a bead coater device is used, and the drying is preferably heat drying at 40 to 200 ° C. for 10 minutes to 6 hours under static or blown conditions.

The solvent that dissolves the charge transfer material varies depending on the type of resin or the like, and is preferably selected from those that do not affect the later-described charge generation layer or undercoat layer during coating.

Specifically, aromatic hydrocarbons such as benzene, xylene, ligroin, monochlorobenzene and dichlorobenzene, ketones such as acetone, methyl ethyl ketone and cyclohexanone, alcohols such as methanol, ethanol and isopropanol, ethyl acetate, Esters such as methyl cellosolve, carbon tetrachloride,
Aliphatic halogenated hydrocarbons such as chloroform, dichloromethane, dichloroethane and trichlorethylene, ethers such as tetrahydrofuran and dioxane, N,
Amides such as N-dimethylformamide, N, N-dimethylacetamide, and sulfoxides such as dimethylsulfoxide are used.

The thickness of the charge transfer layer of the electrophotographic photosensitive member is preferably 10 to 25 μm. The charge transfer layer also contains other existing charge transfer materials, such as CT405,
CT191 (trade name) and the like, and various kinds of commonly used additives such as an ultraviolet absorber and an electron absorbing material can be added as necessary. Further, an appropriate binder may be added in order to obtain stronger film forming properties.

As the charge generating material, a known photoconductive material, for example, an inorganic material such as CdS, Se, ZnO or a phthalocyanine having a metal atom such as Cu, Al, In, Ti, Pb or V, or none. Metal phthalocyanine,
Organic materials such as azo pigments, bisazo pigments, and cyanine pigments can be used alone or in combination.

The solvent that dissolves the charge generating material varies depending on the type of resin or the like, and is preferably selected from those that do not affect the undercoat layer, which will be described later, during coating.

Specifically, aromatic hydrocarbons such as benzene, xylene, ligroin, monochlorobenzene and dichlorobenzene, ketones such as acetone, methyl ethyl ketone and cyclohexanone, alcohols such as methanol, ethanol and isopropanol, ethyl acetate, Esters such as methyl cellosolve, carbon tetrachloride,
Aliphatic halogenated hydrocarbons such as chloroform, dichloromethane, dichloroethane and trichlorethylene, ethers such as tetrahydrofuran and dioxane, N,
Amides such as N-dimethylformamide, N, N-dimethylacetamide, and sulfoxides such as dimethylsulfoxide are used.

The thickness of the charge generation layer of the electrophotographic photosensitive member is 0.1 to 0.5 in order to maintain chargeability and ensure stability.
μm is preferred. If necessary, a plasticizer or the like can be used together with the binder. The coating can be performed by a method similar to that of the charge transfer layer described above.

As the binder resin used in the undercoat layer, nylon 6, nylon 66, nylon 1
1, alcohol-soluble polyamide resin such as nylon 610, copolymer nylon, and alkoxymethylated nylon,
Casein, polyvinyl alcohol resin, nitrocellulose resin, ethylene-acrylic acid copolymer, gelatin, polyurethane resin, polyvinyl butyral resin are used. The undercoat layer can be applied by a method similar to that for the charge transfer layer and the charge generation layer described above. At this time, the thickness of the undercoat layer is 0.1 to 20 μm, preferably 0.5 to 10 μm. Further, these undercoat layers can be omitted if necessary. The charge transfer material of the present invention is suitable not only for use in copying machines, but also for solar cells, light conversion elements, and absorption materials for optical disks.

[0026]

The hydrazone compound represented by the general formula (I) has a reduced crystallinity due to the reduction of a part of the carbazole ring and can form a film by itself. Conventional low-molecular-weight photoconductive compounds are dispersed in a binder to form a film,
Although the drawback of adhesiveness was solved, the hydrazone compound represented by the general formula (I) alone has excellent film-forming property, so that the charge-transfer material can be formed into a film at a high concentration and high-sensitivity electrophotography. A photoreceptor is obtained.

[0027]

EXAMPLES Examples of the present invention will be described in detail below, but the present invention is not limited to the following examples as long as the gist thereof is not exceeded.

FIG. 1 is a schematic sectional view of an electrophotographic photosensitive member manufactured in this embodiment. In the figure, 1 is a charge transfer layer, 2 is a charge generation layer, 3 is an undercoat layer, and 4 is an aluminum substrate. .. Example 1 A small amount of p-toluenesulfonic acid was added to 50 ml of a benzene solution containing 5, 5 g of aldehyde (IV) and 4, 6 g of 1,1-diphenylhydrazone, and the mixture was refluxed for 6 hours. After always performing further treatment, recrystallization was performed using an ethanol solvent to obtain a yellow powder of compound (V).

[0029]

[Chemical 4]

[0030]

[Chemical 5]

The following compounds were similarly synthesized.

[0032]

Example 2 As shown in FIG. 1, an undercoat layer 3 made of nylon (CM4000: Toyobo) is formed on an aluminum substrate 4.
And a butyral film (0.1 μm) containing phthalocyanine as the charge generation layer 2 on the undercoat layer.
Thick). Further, a solution of the compound (V) in dichloromethane (2: 5 weight ratio) was applied thereon, and the temperature was kept at 80 ° C. for 30 minutes.
It was baked for a minute to form a charge transfer layer 1 having a thickness of 15 μm.
The coatability of the film was good and a film having sufficient coating strength was obtained. Using the electrostatic recording tester manufactured by Kawaguchi Denki, the surface potential was set to -900 V by corona discharge of -5 kV, and then dark decay was performed for 3 seconds, and white light of 5 lux was irradiated for 5 seconds. The time (sec) until it became is obtained, and the half exposure amount (lux seconds) was obtained. The result is a half exposure of 0.4
It showed very good photoconductor characteristics such as lux seconds, charge retention rate of 91% and residual potential of -2V. Examples 3 to 7 Measurements were performed in the same manner as in Example 2 except that the hydrazone compounds shown in Table 1 below, which were synthesized in the same manner as in Example 1, were used instead of the compound (V) used in Example 2. The sensitivities of the obtained electrophotographic photosensitive members are shown in Table 1 below.

[0034]

[Table 1]

Example 8 The same as Example 2 except that the compound (V) / polycarbonate / dichloromethane (9: 1: 25) solution was used in place of the dichloromethane solution of (V) used in the above Example 2. It was measured. The results showed good photosensitivity with a half-exposure amount = 0.4 lux seconds, a charge retention rate of 92%, and a residual potential of −3V. Example 9 Instead of the dichloromethane solution of (V) used in Example 2 above, compound (V) / 1,1-bis (p-N, N-diethylaminophenyl) -4,4-diphenyl-1,3.
Measured as in Example 2, but using the butadiene / polycarbonate / dichloromethane (6: 3: 1: 25) solution. As a result, a half-exposure amount of 0.3 lux seconds, a charge retention rate of 92%, and a residual potential of -2V, which are very high photoconductor characteristics. Comparative Example 1 Instead of the compound (V) used in Example 2, the compound (V
An attempt was made to form a film by using I) in the same manner as in Example 2, but crystals were deposited and the film strength was not sufficient, so that the performance could not be evaluated. Comparative Example 2 Instead of the compound (V) used in Example 2, the compound (V
The measurement was performed in the same manner as in Example 2 except that I) / polycarbonate (1: 1 weight ratio) was used. The result is the half exposure =
0.7 lux seconds, charge retention 90%, residual potential -20
It was V.

[0036]

[Chemical 6]

[0037]

As described in detail above, the electrophotographic photosensitive member of the present invention has excellent high sensitivity characteristics, small residual potential and dark decay, and little light fatigue, and thus exhibits good repeated stability. Has features.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of an example of an electrophotographic photosensitive member according to the present invention.

[Explanation of Codes] 1 charge transfer layer 2 charge generation layer 3 undercoat layer 4 aluminum substrate

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[Procedure amendment]

[Submission date] September 5, 1991

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[0009]

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[Correction target item name] 0036

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[0036]

[Chemical 6]

Claims (1)

1. An electrophotographic photosensitive member containing at least a charge transfer material and a charge generation material, wherein the charge transfer material is a hydrazone compound represented by the following general formula (I). Electrophotographic photoreceptor. [Chemical 1]