JPS6063538A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To improve flexibility and adhesion, to enhance sensitivity, and to prevent rise of residual potential by forming a photosensitive layer contg. a specified hydrazone compd. on a conductive substrate. CONSTITUTION:A photosensitive layer formed on a conductive substrate contains a hydrazone compd. represented by formula I in which X is a heterocyclic group; R1-R3 are each H, alkyl, aralkyl, or aryl, and both of R1 and R2 are not simultaneously H. Such a hydrazone compd. functions as an electrostatic charge transfer substance, and a charge transfer layer 3 is formed on a charge generating layer 2 on the substrate 1 by using this charge transfer substance and, for example, a polymer as a binder 4 to form a laminate type. This hydrazone compd. may be dispersed into the binder 4 together with a charge generating substance 2 to form a sigle layer type. In both cases, the hydrazone compd. acts effectively, it has superior flexibility and adhesion, and a good photosensitive body high in sensitivity and prevented from rise of residual potential can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrophotographic photoreceptor. More specifically, the present invention relates to an electrophotographic photoreceptor containing a low-molecular organic photoconductive substance as a main component.

Conventionally, inorganic materials such as selenium, cadmium sulfide, and zinc oxide have been widely known as electrophotographic photoreceptors. These materials have the characteristics necessary for electrophotographic photoreceptors, such as being able to be charged to an appropriate potential in the dark, having little charge dissipation in the dark, and being able to quickly dissipate charge when irradiated with light. However, at present, problems remain in terms of thermal stability, flexibility, durability, etc. Furthermore, these inorganic substances pose problems in handling such as production and disposal due to their toxicity.

On the other hand, electrophotographic photoreceptors made of organic materials have advantages such as being relatively easy and inexpensive to manufacture, allowing a wide range of properties to be changed by changing the structure of the compound, and having excellent moldability. Therefore, many studies have been conducted in recent years.

Poly-N-vinylcarbazole is well known as such an organic photoconductive material, and 2.4.
7-) A photoreceptor made of a charge transfer complex of linitrofluorene has already been put into practical use. However, poly-N-vinylcarbazole has problems with flexibility and adhesion, and when plasticizers are added to improve these points, sensitivity decreases, residual potential increases, and it does not have film forming properties. By using it in combination with a suitable binder, a photoreceptor with excellent flexibility and adhesiveness can be obtained, but in general, many of them are insufficient in terms of sensitivity.

Therefore, the present inventors conducted intensive studies to obtain an electrophotographic photoreceptor that has improved these drawbacks, and as a result, discovered that a hydrazone compound represented by the following general formula (I) is suitable, and has developed the present invention. reached.

That is, the electrophotographic photoreceptor of the present invention has the following general formula (Tl
It contains a hydrazone compound represented by:

In the formula, X represents a heterocyclic group which may have a substituent.

Specific examples include a pyrrole ring group, a pyrazole ring group, a pyrimidine ring group, a pyridazine ring group, a pyrrole ring group, an indole ring group, an imidazole ring group, a benzimidazole ring group, a carbazole ring group, a thiophene ring group, and a thiazole ring. group, a benzothiazole ring group, a furan ring group, an oxazole ring group, a benzofuran ring group, a dibenzofuran ring group, a benzoxazole ring group, and the like.

Substituents for these heterocycles include alkyl groups such as methyl and ethyl groups, alkoxy groups such as methoxy and ethoxy groups, aryl groups such as phenyl and tolyl groups, and dialkylamino groups such as dimethylamino and diethylamino groups. group, halogen atoms such as chlorine atom, bromine atom, nitro group, and cyano group.

Also R1. R2 and R3 represent a hydrogen atom or an alkyl group, an aralkyl group, or an aryl group which may have a substituent. (However, except when R1 and R2 are hydrogen atoms at the same time) More specifically, it is an aryl group selected from methyl, ethyl, prokyl, phenyl, naphthyl, anthryl, etc. Examples of groups include methyl groups, alkyl groups such as ethyl atom, alkoxy groups such as methoxy and ethoxy groups, aryl groups such as phenyl and tolyl groups, dialkylamino groups such as dimethylamino and diethylamino groups, chlorine atoms, and bromine atoms. Examples include halogen atoms, nitro groups, cyan groups, etc.

Specific examples of preferred hydrazone compounds in the present invention are listed below.

(6) (6) The hydrazone compound of the present invention acts effectively as a highly conductive substance in an electrophotographic photoreceptor, but especially when used as a charge transport substance in combination with a suitable charge generating substance. Shows favorable properties.

An example of a form in which hydrazone represented by the general formula (Il) is used as a charge transport material is, for example, as shown in FIG. There is a multilayer type in which a charge transport layer made of a compound is formed, or a single layer type in which a photosensitive layer is formed on a conductive substrate by dispersing a hydrazone compound together with a charge generating substance in a binder, as shown in Figure 2. However, the hydrazone compound of the present invention effectively acts as a charge transport substance in any case.

As the charge generating substance used in the present invention, known materials are used.

For example, organic compounds such as spherical methine phosphate dyes, cyanine compounds, disazo compounds, metal phthalocyanine complexes, selenium or selenium alloys, inorganic materials from groups N and II (Cd5-5e), or amorphous silicon. Either can be used.

In the case of the laminated type photoreceptor shown in Fig. 1, the charge generation layer is formed on a conductive substrate by a coating method, a spraying method, a vacuum evaporation method, a sputtering method, etc., and the thickness is generally 0.08 μmN.
It is 10 μm.

The hydrazone compound represented by the above-mentioned general formula (I) is used as the charge transport material of the present invention, but when used in a laminated charge transport layer, since the hydrazone compound itself does not have film-forming properties, a suitable binder is generally used. It is preferable to use it together. Usually, considering sensitivity, mechanical strength, etc., the binder is 0.3 per hydrazone compound.
The amount used is from parts by weight to 4 parts by weight, preferably from 1 part by weight to 8 parts by weight. As a binder, polycarbonate,
Polyester (9), phenoxy resin, epoxy resin, phenolic resin,
Polymer materials such as acrylic resin, vinyl chloride resin, and polystyrene are used.

The thickness of the charge transport layer is 1 μm to 80 μm, preferably 5 μm to 20 μm.

In addition, in the case of the single-layer type photoreceptor shown in FIG. 2, the above-mentioned charge-generating substance and the hydrazone compound represented by the general formula (Il) are dispersed in the above-mentioned binder using an appropriate solvent, and a 'conductive The photosensitive layer is coated on a transparent substrate and dried to form a photosensitive layer. The thickness of the photosensitive layer is 8 μm = 80 μm, preferably 5 to 20 μm.
It is μm. In this case, the proportion of the charge generating substance in the photosensitive layer is 60 wt% or less, preferably 5 to 80 wt%, and the proportion of the charge transporting substance is 5 to 9 wt%, preferably 1O to
It is 80 wt%.

Examples of the present invention are shown below, but the present invention is not limited thereto.

Example 1 Titanium phthalocyanine was converted into 5XIQ-61-l (To
rr), and was vapor-deposited on an aluminum substrate (60 x 60 x l m) to form a charge generation layer while monitoring with a quartz crystal film thickness (10) meter (CRM type manufactured by Nippon Vacuum Technology Co., Ltd.). did.

Next, 4-diethylaminophenyl-1-car-N-aldehyde-N-benzothiazolehydrazone (
O @ compound) 1 part by weight and polycarbonate (Niepilon S 2000 manufactured by Mitsubishi Gas Chemical) 11! A solution of Otoribe dissolved in 27 parts by weight of dichloromethane was prepared, and this solution was applied onto the charge generation layer using an applicator.
It was dried at ℃ for 1 hour to form a charge transport layer having a thickness of 18 μm after drying.

In order to examine the performance of the photoreceptor thus prepared, measurements were carried out using an electrostatic charging testing device (manufactured by Kawaguchi Electric, 5P428) using a semiconductor laser (HLP1600, a new product of Hitachi Seisakusho) as a light source. The wavelength of the semiconductor laser is 880 nm, and the output power is 2 mW. The laminated photoreceptor of the present invention was set in an electrostatic charging test device, and corona charging was performed at a voltage of -6 KV at a speed of 5 m/min. After being held in a dark place for 5 seconds, laser light was irradiated to attenuate the light. was measured. As a result, the initial potential immediately after corona charging was 720V, and it became 580V after 5 seconds in the dark. The half-reduction exposure amount was 36 μJ/cd, and the residual potential 15 seconds after the start of light irradiation was 60 V.

The attenuation curve of this electrophotographic photoreceptor is shown in FIG.

Example 2 4 parts by weight of chloraluminum phthalocyanine, 8 parts by weight of 4-diethylaminophenyl-1-carbaldehyde-N-benzothiazol-hydrazone, and 50 parts by weight of phenoxy resin were mixed in 1 km of tetrahydrofuran sbo, and dispersed for 8 hours with a paint conditioner. did.

Next, this solution was applied to an aluminum substrate (4×4×O,
lm) with a wire bar V and 100°C.
A single layer type photoreceptor was prepared by drying for a period of time. The film thickness after drying was 8 μm.

When the electrophotographic properties of this photoreceptor were measured in the same manner as in Example 1, the initial potential was 560 .mu., the potential after 5 seconds in the dark was 460 V, and the half-reduction exposure was 217 μJ/ml. The residual potential 15 seconds after light irradiation was 160V.

[Brief explanation of the drawing]

FIG. 1 and FIG. 2 are diagrams showing an example of the structure of the electrophotographic photoreceptor of the present invention. ] - Conductive substrate 2 - Charge generating substance 8 - Charge transporting substance 4 - Binder FIG. 8 is a light attenuation curve of the laminated photoreceptor of Example 1 according to the present invention during charged exposure. (1B complete) 1st [il Fig. 2

Claims (1)

[Scope of Claims] An electrophotographic photoreceptor comprising a photosensitive layer containing a hydrazone compound represented by the following general formula (tl) on a conductive substrate. (In the formula, X may have a substituent. Represents a heterocyclic group. R1, R2* and R3 represent a hydrogen atom or an alkyl group, an aralkyl group or an aryl group which may have a substituent. However, this excludes the case where R1+R2 are hydrogen atoms at the same time. )