JPS62229252A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To provide an excellent electrostatic charge characteristic and residual potential characteristic and to decrease the deterioration in various characteristics by repetitive uses by incorporating at least one kind of the amidine compd. expressed by the specific formula into a photosensitive layer of an electrophotographic sensitive body. CONSTITUTION:The photosensitive layer of the electrophotographic sensitive body consisting of a conductive substrate and the photosensitive layer laminated on said substrate contains at least one kind of the amidine compd. expressed by the formula, by which the excellent photosensitivity is provided to the electrophotographic sensitive body and the stability thereof to light, heat and ozone is improved. The electrophotographic sensitive body which has the high durability as well as the excellent electrostatic charge characteristic and residual potential characteristic and is less deteriorated in the various characteristics by the repeated uses is thus obtd.

Description

Detailed Description of the Invention [Objective of the Invention] (Industrial Application Field) The present invention relates to an electrophotographic photoreceptor that is effective for use in the Carlson method, and more specifically, it has excellent photosensitivity, excellent charging characteristics, and The present invention relates to an electrophotographic photoreceptor having good stability in potential characteristics and excellent durability.

(Prior Art) The photoconductive process of electrophotographic photoreceptors consists of a photocharge generation process and a charge transport process.

Conventionally known electrophotographic photoreceptors can be roughly divided into those in which the above two processes are performed using a single material, and those in which the two processes are performed using separate materials.

Of the two methods described above, the latter type involves the use of a thin layer of charge generating material, e.g. forward running selenium, on a conductive support made of a conductive 4A material, e.g. brass, aluminium. A stacked structure in which a thin layer of a charge transport material such as polyvinylcarbazole is further provided on the layer is well known. This stacked structure allows a wider selection of materials to be used for the photoreceptor, has excellent electrophotographic properties such as sensitivity and acceptance potential, and has excellent coating properties when forming the photoreceptor. This method has the advantage that it is possible to manufacture a photoreceptor with a high temperature.

However, since the polyvinyl carbazole used for the charge transport layer lacks flexibility, the formed layer is hard and brittle, and is prone to cracking and peeling.
The drawback is that it has poor durability as a photoreceptor. Therefore, in order to increase the flexibility of polyvinylcarbazole, a method of using it together with a plasticizer has been proposed. However, this method
This has a major disadvantage in that residual charges in the charge transport layer increase, causing fog in images and deteriorating electrophotographic properties.

It has also been proposed to use a low molecular weight organic compound as a charge transport material. Some of these low molecular weight compounds, such as 2,5-bis(p-diethylaminophenyl)-1,3°4-oxinasiazole, have relatively excellent electrophotographic properties. It is also known that it has

(Problems to be Solved by the Invention) However, even if the above-mentioned low molecular weight organic compounds have good electrophotographic properties, there is a problem in that they generally lack film-forming ability. For this reason, a charge transport layer is formed by using a polymer binder with film-forming ability, but this type of low molecular weight organic compound is generally incompatible with polymer binders. However, when a film is formed as a charge transport layer, it tends to precipitate and has poor thermal stability.

The present invention eliminates the drawbacks of the conventional electrophotographic photoreceptor described above, has excellent photosensitivity, high stability against light, heat, and ozone, is highly durable, and has excellent charging characteristics and residual potential characteristics. The object of the present invention is to provide an electrophotographic photoreceptor whose properties are less likely to deteriorate due to repeated use.

[Structure of the Invention] (Means for Solving the Problems) The electrophotographic photoreceptor of the present invention is an electrophotographic photoreceptor comprising an electrically conductive support and a photosensitive layer stacked on the electrically conductive support. , the photosensitive layer has the following general formula (I> 2 R3 (wherein R1, R2, R3, R4 are an alkyl group, an aralkyl group, an aryl group, J: and a heterocyclic group which may have a substituent). A monovalent group selected from the group consisting of:

The present invention applies to any type of electrophotographic photoreceptor, such as a single-layer photoreceptor in which a single photoconductive layer is provided on a conductive support, and a functionally separated photoreceptor comprising a charge generation layer and a charge transport layer. However, in carrying out the present invention, the preferred type is a photoreceptor with functionally separated charge generation layer and charge transport layer, in which an amidine compound represented by the general formula (I>) is added to the charge transport layer. When the content is mixed, the charging ability and repeatability are particularly good.

Hereinafter, the case where the present invention is applied to a functionally separated photoreceptor) will be explained.

This electrophotographic photoreceptor has a three-layer structure consisting of at least a conductive support, a charge generation layer, and a charge transport layer, and the charge generation layer or the charge transport layer is sequentially stacked on the conductive support. There is. Although the order in which the charge generation layer and the charge transport layer are stacked on the conductive support is not particularly limited, from the viewpoint of increasing the physical strength of the photoreceptor, the conductive support, the charge generation layer, and the charge Ir with transport layers stacked in this order
1g) Blue one is preferred.

The conductive support used in the present invention is not particularly limited, and may be any support that is normally used as a conductive support for electrophotographic photoreceptors. Such supports include, for example, fully flexible materials such as brass, aluminum, gold, and silver; metal surfaces coated with a thin film of PlusDek; metal-coated paper, metal-coated PlusDEC sheets, or Examples include glass coated with a conductive layer such as aluminum iodide, copper iodide, chromium oxide, or tin oxide. These are used as thin cylindrical sheets with appropriate thickness, hardness, and flexibility, and either the support itself is conductive or its surface is conductive, and has sufficient strength for handling. It is preferable that the material is of high quality.

A charge generation layer or a charge transport layer is formed on such a conductive support.

The charge generation layer may be made of any charge generation material as long as it absorbs light and generates charges (carriers) with high efficiency.

Such charge generating substances include, for example, selenium and urelene alloys: CdS, CdSe, Cd55c.
, ZnO and ZnS; phthalocyanine pigments such as metal phthalocyanines and non-metal phthalocyanines; azo dyes such as monoazo dyes and disazo dyes; penylene pigments such as penylene anhydride and penylene imide; indigoid dyes ; Quinacridone pigments; Polycyclic quinone pigments such as anthraquinones and pyrenequinones; Cyanine dyes: xanthene dyes; Charge transfer consisting of electron-donating substances such as poly-N-vinylcarbazole and electron-accepting substances such as trinitrofluorenone 211 body; and eutectic 1 (1 body) consisting of pyrylium salt dye and polycarbonate 1 to 1 fat.

Methods for forming the charge generation layer vary depending on the type of charge generation substance used, but include various coating methods such as spin coating, pulling method, roller coating method, doctor blade coating method, etc. For example, plasma CVD using vacuum steaming method, sputtering method, glow discharge
The law can be selected and applied as appropriate.

The thickness of the charge generation layer to be formed at this time is appropriately determined depending on the charging characteristics required for the electrophotographic photoreceptor.
Usually, it is preferably about 0.1 to 5 μm.

Note that when forming the charge generation layer on the conductive support,
If necessary, an adhesive layer may be formed between the conductive support and the charge generation layer. As the material for forming and covering the contacting layer, conventionally commonly used materials such as casein can be used, and the thickness thereof is 0.1 to 10 μm, preferably 0.1 μm.
Approximately 5 to 2 μm is preferable.

The charge transport layer contains at least one amidine compound represented by the general formula (I).

In this compound (1), the heterocyclic group includes a pyrrole ring group, an indole ring group, an indole ring group, an isoindole ring group, a carbazole ring group, a furan ring group, a benzofuran ring group, a diophene ring group, and a pyrazole ring group. cyclic group, pyrazoline cyclic group, benzopyrazole cyclic group, indole cyclic group, imidacillin cyclic group, benzimidazole cyclic group, oxazole cyclic group, penzaoxazole cyclic group, naphthoxazole cyclic group,
Oquinacillin ring group, thiazole ring group, thiazoline ring group,
Henzodiazoline ring group, triazole ring group, henzytriazole ring group, oxadiazole ring group, deadiazole ring group, benzoxadiazole ring group, benzothiadiazole ring group, tetrazole ring group, lysine ring group, quinoline ring group, acridine ring group, phenanthridine LAN, benzoquinoline ring group, naphthoquinoline hA'l, pyran ring group, benzopyran ring group, thiapyran lil, goridazine r2 group, pyrimidine ring group, pyrazine, oxazine IMN
, pendioquinazine ring group, defuzine ring group, benzothiazine ring group, phenodeazine 1mD, dioxane ring group, triazine ring group, oxadiazine t! , thiadiazine ring group,
detrazine ring group, benzofuran ring group, deazole ring group,
benzodeazole) MW, naphthothiazole W? W,
Examples include selenazole LMM, benzoselenazole ring group, naphthoxazole ring group, and the like.

J3 in this compound, the aryl group includes, for example, a di-substituted amino group (e.g., a dialkylamino group such as a dimethylamino group, a ditolylamino group, a dibutylamino group, a methylethylamino group, a methylbutylamino group, a cyamylamino group, etc.) group, dialkylamino group such as diphenethylamino group, diarylamino group such as diphenylamino group, ditolylamino group, ditolylamino group), alkoxy group (e.g. methoxy group, ethoxy group, propoxy group, butoxy group) and 7-lyl group. Oxy group (for example, phenoxy group, nano-1 to xy group), alkyl group, nitro group, cyano group, hydroxy group, avidel group, phenyl group, naphthyl group, anthracene group, phenanthrene group that may be moxabed by halogen. , tetralin group, azulene group, biphenylene group, acenaphthylene group, acenaphthene group, fluorene group, fluoranthene group, triphenylene group, pyrene group, chrysene group, naphthacene group,
Pyrene group, perylene group, benzopyrene group, rubycene group,
Examples include coronene group and obalene group.

In the above compound, examples of the aralkyl group include:
Disubstituted amide 7-base (e.g. dimethylamino group, diethylamino group, dibutylamino group, methylethylamino group,
dialkylamino groups such as methylbutylamino group and siamylamino group; dialkylamino groups such as dibenzylamino group and diphenethylamino group; diarylamino groups such as diphenylamino group, ditolylamino group, and tuxylylamino group) and alkoxy groups ( For example, substituted with methoxy group, ethoxy group, propoxy group, butoxy group), aryl base oxy Li (19!I, phenoxy group, naphthoxy group), alkyl group, nitro group, cyano group, hydroxy group, acetyl group, or halogen. a benzyl group which may be
Examples include phenethyl group, phenylpropyl group, phenylbutyl group, naphthylmethyl group, and naphthylethyl group.

In the above compounds, the alkyl group includes, for example, a di-substituted amino group (e.g., a dialkylamino group such as a dimethylamino group, a diethylamino group, a dibutylamino group, a methylethylamino group, a methylbutylamino group, a siamylamino group; a dibenzylamino group) , dialkylua such as diphenethylamino group.

mino group; diarylamino group such as diphenylamino group, ditolylamino group, tuxylylamino group) and alkoxy group (e.g. methoxy group, ethoxy group, propoxy group,
butoxy group), aryloxy group (e.g., phenoxy group, naphthoxy group), yanitro group, cyano group, hydroxy group, acetyl group, methyl group, ethyl group, propyl group, isopropyl group, butyl group, which may be substituted with halogen, Examples include pentyl group and hexyl group.

Substituents for organic groups constituting the above-mentioned heterocyclic groups, aryl groups, aralkyl groups, alkyl groups, etc. include, for example, alkyl groups such as methyl, ethyl, and propyl; methylene, ethylene, and propylene groups; Alkylene groups such as; alkoxy groups such as methoxy and ethoxy groups; aryloxy groups such as phenoxy; halogen atoms such as chlorine and bromine; dialkylamino groups such as dimethylamino, diethylamino and ethylbutylamino groups; diphenylamino Diarylamino groups such as ethylphenyl hexaminol; alkylthio groups such as methylthio group and ethylthio group; nitrobase diarylamino group; hydroxyl group; ester of medyl ester base, ethyl ester group, phenyl ester MW groups; amide groups such as phenylamide groups and dimethoxyphenylamide groups; di-substituted amino groups (e.g., dialkylamino groups such as dimethylamino groups, diethylamino groups, dibdelamino groups, methylethylamino groups, methylbutylamino groups, and cyamyl amino groups); dialkylamine groups such as dibenzylamino group and diphenethylamino group; diarylamino groups such as diphenylamino group, ditolylamino group, and tuxylylamino group) and alkoxy groups (e.g., methoxy group, ethoxy group, propoxy group, butoxy group) and aryloxy group (
For example, a phenyl group, a naphthyl group, which may be substituted with an acetyl group, an acetyl group, a halogen group, an alkylanitro group, a cyano group, a naphthoxy group,
Anthracene group, phenanthrene group, tetralin group, azulene group, biphenylene group, acenaphthylene group, acenaphthene group, fluorene group, fluoranthene group, triphenylene group, pyrene group, chrysene group, naphthalene group, pyrene group, perylene group, benzopyrene group, rubicene group Aryl groups such as , coronene group, obalene group; di-substituted amino group (
For example, dialkylamino groups such as dimethylamino group, diethylamino group, dibdelamino group, methylethylamino group, methylbutylamino group, siamylamino group; dialkylamino groups such as dibenzylamino group, diarylamino group; diphenylamino group, ditolylamino group diarylamino groups such as tuxylylamino), alkoxy groups (e.g., methoxy, ethoxy, propoxy, butoxy), aryloxy groups (e.g., phenoxy, naphthoxy), alkyl groups, nitro groups, etc. Examples thereof include a cyano group, a hydroxy group, an azetyl group, and an aralkyl group such as a benzyl group, a phenethyl group, a phenylpropyl group, a phenylbutyl group, a naphthylethyl group, and a naphthylethyl group, which may be substituted with a halogen.

Specific examples of the amidine compounds represented by the above formula using @formula include those shown in Table 1 below. That is, (blank below) Table 1 RAN-C=NR4 (blank below) When forming a charge transport layer containing these compounds as essential components, none of these compounds have film-forming properties, so for example, as described below, It is necessary to form a layer by using a resin solution prepared by dissolving such a polymer compound in an appropriate organic solvent as a binding component.

Examples of such polymer compounds include polycarbonate, polyester carbonate, polystyrene, polyvinyl chloride, acrylic resin, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, polyvinyl acetal,
Known binders for electrophotographic photoreceptors include phenolic resins, styrene-acrylic copolymers, polyarylates, and alkyd resins.

In layer formation, the above-mentioned amidine compound 1
The above-mentioned polymer compound is preferably added in an amount of 0.1 to 0.1 to parts by weight.
A solution obtained by dissolving or dispersing a compound containing five bases in an organic solvent such as an aliphatic chlorine type, aromatic hydrocarbon type, aromatic chlorine type, ether type, ester type, ketone type, etc. is usually prepared. For example, it may be coated on the charge generating layer or on the conductive support by a spin coating method, a pull-up method, a roller coating method, a doctor blade coating method, etc., and then dried.

Note that the above-mentioned amidine compounds may be used in combination of two or more types, or may be used in combination with known charge transport substances within the range that does not impair the effects of the present invention.

The total thickness of the charge transport layer, including the charge generation layer and the charge transport layer, is preferably 100 μm or less.

This is because if the total thickness h1 exceeds 100 μm, the flexibility and photosensitivity of the formed film will decrease.

(Function) The electrophotographic photoreceptor according to the present invention has a low dark decay rate, a high charging ability, and excellent charging characteristics, and has excellent photosensitivity characteristics with a small amount of half-decreased exposure. In addition, it is stable against light, heat, and ozone, maintains stable charging characteristics, photosensitivity characteristics, and residual potential characteristics even during long-term use, and has excellent durability.

(Example) Examples of the present invention will be described below.

Examples 1-6 Aluminum-deposited polyethylene terephthalate 1
~Using a film as a conductive support, a charge generating substance as shown in Table 2 is deposited on the surface on which aluminum is vapor-deposited by vapor deposition or coating to produce a film as shown in Table 2. A thick charge generation layer was formed.

Roughly selecting the compounds shown in Table 2 from among the amidine compounds numbered in Table 1,
A solution prepared by dissolving this amidine compound and a polymer compound was applied by a pulling method and dried at 90'C for 24 hours to form a charge transport layer having a thickness as shown in Table 2.

Measure the chargeability (initial value of the photoreceptor surface potential when charged) and photosensitivity (the amount of exposure required for the initial value of the surface potential to attenuate by half) of the photoreceptor thus obtained. do,
The results are shown in Table 2.

Further, the dark decay rate (rate of decay of the surface potential of the photoconductor as it fades in the dark) and residual potential (the point at which surface potential decay rapidly slows down due to exposure) of the photoconductor were as shown in Table 2.

When this photoreceptor was repeatedly charged and exposed to light in an environment where heat, ozone, etc. were generated, no abnormalities were observed and there were only small fluctuations in charging ability, photosensitivity, residual potential, etc. It turned out that it has excellent characteristics.

Comparative Examples 1 and 2 Electrophotographic photoreceptors were produced in the same manner as in Examples except that a pyrazoline derivative was used as the charge transport material.

The charging ability, photosensitivity, dark decay rate, and residual potential of this photoreceptor were measured and shown in Table 2.

When this photoreceptor was repeatedly charged and exposed 10,000 times in an environment where heat, ozone, etc. were generated, changes in charging ability, photosensitivity, residual potential, etc. were observed, and the fatigue resistance was compared with the example. It was inferior.

(The following is a blank space) [Effects of the Invention] As is clear from the results of the Examples, the electrophotographic photoreceptor of the present invention has excellent charging characteristics with a small dark decay rate and a large charging ability, and also has excellent charging properties with half-life exposure. It has a small amount and exhibits a light sensitivity characteristic. Furthermore, the electrophotographic photoreceptor of the present invention has stability against light, heat, and ozone, and maintains stable charging characteristics, photosensitivity characteristics, and residual potential characteristics even when used for a long time. It has excellent durability.

Claims (1)

[Claims] (1) In an electrophotographic photoreceptor consisting of a conductive support and a photosensitive layer stacked on the conductive support, the photosensitive layer has the following general formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ ( In the formula, R_1, R_2, R_3, and R_4 represent a monovalent group selected from the group consisting of an alkyl group, an aralkyl group, an aryl group, and a heterocyclic group that may have a substituent. An electrophotographic photoreceptor characterized by containing at least one of the following.