JPS61295557A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To increase the sensitivity of a sensitive body by forming layers each contg. a specified compound as the charge generating and transferring layers. CONSTITUTION:A polycyclic quinone pigment represented by formula I is used in a charge generating layer. A ketazine compound represented by formula II is used in a charge transferring layer. In the formula II, each of R1, R2, R5, R6 and R7 is H, halogen, optionally substituted alkyl, alkoxy, optionally substituted aryloxy or substituted amino, at least one between R1 and R2 is substituted amino or alkoxy, each of R3 and R4 is optionally substituted alkyl or optionally substituted aryl, at least one between R3 and R4 is optionally substituted aryl and n=0 or 1. Thus, a laminate type electrophotographic sensitive body having high sensitivity is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] No. 373,151 relates to an organic photoconductor, and particularly to an electrophotographic photoreceptor having a charge transport layer and a charge generation layer.

[Conventional technology]

Electrophotographic photoreceptors using inorganic photoconductors such as selenium, cadmium sulfide, and zinc oxide as photosensitive components have been known so far.

On the other hand, since the discovery that certain organic compounds exhibit photoconductivity, a number of organic photoconductors have been developed8. carbazole,
Low-molecular organic photoconductors such as anthracene, pyrazolines, oxadiazoles, hydrazones, polyarylalkanes, phthalocyanine pigments, azo pigments, cyanine dyes, polycyclic pigments, perylene pigments, indigo dyes, thioindigo Organic pigments and dyes such as dyes or squaric methine dyes are known. In particular, organic pigments and dyes with photoconductivity are easier to synthesize than inorganic materials, and the parity range has been expanded to allow selection of compounds that exhibit photoconductivity in an appropriate wavelength range.
Many photoconductive organic pigments and dyes have been proposed.

For example, US Patent No. 4,123,270.

Same No. 4247614, Same No. 42.51613, Same No. 4251614, Same No. 4256821, Same No. 426
No. 0672, No. 4268596, No. 427874
No. 7, No. 4293628, etc., an electrophotographic photoreceptor using a disazo pigment exhibiting photoconductivity as a charge generation substance in a photosensitive layer that is mechanically separated into a charge generation layer and a charge transport layer. It has been known.

Electrophotographic photoreceptors using such organic photoconductors can be produced by coating by appropriately selecting a binder, so it is possible to provide photoreceptors with extremely high productivity and at low cost. It has the advantage of being able to freely control the sensitive wavelength range.

A multilayer photoconductor obtained by laminating a charge transport layer and a charge generation layer mainly composed of a charge generation material has advantages over other single-layer photoconductors in terms of sensitivity and increased residual potential after durability tests. However, it was still not at a sufficient level.

[Problem that the invention seeks to solve]

SUMMARY OF THE INVENTION An object of the present invention is to improve the above-mentioned drawbacks and provide a laminated electrophotographic photoreceptor with high sensitivity and extremely low residual potential even after a durability test.

The present invention aims to provide a laminated electrophotographic photoreceptor having two layers, a charge generation layer containing a charge generation material as a main component and a charge transport layer containing a charge transport material as a main component, on a conductive support L. This is achieved by using a specific polycyclic quinone pigment in the charge generation layer and having a specific ketazine compound in the charge transport layer.

[Means for solving problems]

The present invention provides a multilayer electrophotographic photoreceptor in which a charge generation layer and a charge transport layer are provided on a conductive support, in which the charge generation layer consists of a layer containing a polycyclic quinone pigment represented by formula (I). It happens.

The charge transport layer has the general formula (II) (wherein R1 and R2 represent a hydrogen atom, a halogen atom, a substituted or substituted alkyl group, an alkoxy group, a substituted or unsubstituted aryloxy group, or a substituted amino group, with the proviso that At least one of R1 and R2 is a substituted amine group or an alkoxy group. R3 and R4 are
It represents a substituted or unsubstituted alkyl group or a substituted or unsubstituted 7-aryl group, provided that at least one of R3 and R4 is a substituted or unsubstituted aryl group. Also, R3 and R4 may form a nitrogen-containing heterocycle e
Rs, Rh, R7, and R8 are hydrogen atoms, halogen atoms, and substituted or unsubstituted alkyl groups.

represents an alkoxy group, a substituted or unsubstituted 7-aryloxy group, or a substituted amino group, n represents O or l)
This is an electrophotographic photoreceptor characterized by comprising a layer containing a hydrazone compound represented by:

The present invention will be explained in detail below.

In the laminated electrophotographic photoreceptor of the present invention, the charge generation layer contains as much charge generation material as possible in order to obtain sufficient absorbance, and in order to efficiently inject the generated charge carriers into the charge transport layer. In addition, it is desirable to use a thin film layer, for example, a thin film layer with a thickness of 10 microns or less, preferably 0.01 micron to 1 micron. This means that most of the incident light is absorbed by the charge generation layer. This is due to the need to generate a large number of charge carriers and to inject the roughly generated charge carriers into the charge transport layer without being deactivated by recombination or trapping.

The charge generating material used in the present invention is a polycyclic quinone pigment represented by formula (I).

The charge generation layer can be formed by coating the pigment described in 1 and, if necessary, a charge transporting material together with a suitable binder (or without a binder) on the substrate, or by applying vacuum deposition 1 to the substrate.
It can be obtained by forming a vapor deposited film of ItN.

A wide range of insulating Ii! binders can be used when forming the charge generation layer by coating. It can be selected from resins and organic photoconductive polymers such as poly-N-vinylcarbazole, polyvinylanthracene and polypyrene. Preferably polyvinyl butyral, polyarylate (condensation polymer of bisphenol A and phthalic acid, etc.)
, polycarbonate, polyester, phenoxy resin,
Examples include insulating resins such as polyvinyl acetate, acrylic subpart, polyacrylamide resin, polyamide, polyvinylpyridine, cellulose resin, urethane resin, epoxy resin, casein, polyvinyl alcohol, and polyvinylpyrrolidone. The resin contained in the charge generation layer is
A content of 80% by weight or less, preferably 40% by weight or less is suitable.

The solvent that dissolves these resins varies depending on the type of resin, and is preferably selected from those that do not dissolve the above-mentioned charge generation layer and undercoat layer.

Specific organic solvents include methanol, ethanol,
Alcohols such as Impropatool, ketones such as acetone, methyl ethyl ketone, cyclohexanone, N, N
- Amides such as dimethylformamide and N,N-dimethylacetamide, sulfoxides such as dimethyl sulfoxide, ethers such as tetrahydrofuran, dioxane, and ethylene glycol monomethyl ether, esters such as methyl acetate and ethyl acetate, chloroform, methylene chloride, Dichloroethylene, carbon tetrachloride.

Aliphatic halogenated hydrocarbons such as trichloroethylene, aromatics such as benzene, toluene, xylene, ligroin, monochlorobenzene, dichlorobenzene, etc. can be used.

Coating methods include dip coating method, spray coach ink method, spinner coating method, bead coating method,
This can be carried out using coating methods such as Meyer bar coating method, blade coach ink method, roller coating method, and curtain coating method. Drying is
It is preferable to dry to the touch at room temperature and then heat dry. Heat drying can be carried out at 30° C. to 200° C. for a period of 5 minutes to 2 hours, either stationary or under ventilation.

The charge transport layer is electrically connected to the charge generation layer described above, and 1! It has a mechanism that can receive and take charge carriers injected from the charge generation layer in the presence of a field and transport these charge carriers to the surface. At this time, this charge transport layer is placed on top of the charge generation layer! ? may be layered, or may be laminated underneath.

The substance that transports charge carriers in the charge transport layer (hereinafter simply referred to as charge transport substance) is preferably substantially insensitive to the 11 m wave wavelength range to which the charge generation layer is sensitive. The term "electromagnetic waves" includes the broad definition of "light rays" including gamma rays, X-rays, far infrared rays, and the like. When the photosensitive wavelength range of the charge transport layer coincides with or overlaps that of the charge generation layer, charge carriers generated in both layers trap each other, resulting in a decrease in sensitivity.

The charge transport substance used in the present invention is a ketazine compound represented by general formula (II).

(In the formula, R1 and R2 represent a hydrogen atom, a halogen atom, a substituted or substituted argyl group, an alkoxy group, a substituted or unsubstituted 7-aryloxy group, or a substituted amine group. However, at least one of R1 and R2 is a substituted amino group or alkoxy group, (is, R3 and R4
represents a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group, provided that at least one of R3 and R4 is a substituted or unsubstituted aryl group. Further, R3 and R4 may form a nitrogen-containing heterocycle, and R5, R6, R+, and R8 are a hydrogen atom, a halogen atom, or a substituted or unsubstituted alkyl group.

(represents an alkoxy group, a substituted or unsubstituted aryl group, or a substituted amino group, n represents 0 or 1) This hydrazone compound has the above-mentioned conditions as a charge transport material, and in particular sensitivity.

- Has excellent properties in terms of durability.

Representative compounds of the hydrazone compound represented by the general formula (n) used in the present invention are illustrated in Table 1.

Table 1a Table 1b In addition, in Kibatsu Hitto, a ketazine compound etc. used in the charge transport layer can be added to the charge generation layer.
The #1 feeling effect becomes more noticeable.

When adding a charge transporting material to the charge generation layer, the ketazine compound should be 10 times (weight ratio) or less, preferably 0.01 to 1 times (weight ratio) of the charge generation material to achieve high sensitivity, low residual potential,
This is appropriate from the viewpoint of repeat stability.

To form a charge transport layer containing a hydrazine compound,
Film formation can be achieved by selecting an appropriate binder. Examples of materials that can be used as binders include acrylic resin, polyacrylate, polyester, polycarbonate, and polystyrene.

Acrylonitrile-styrene copolymer, acrylonitrile-butadiene copolymer, polyvinyl butyral,
Examples include insulating resins 5 such as polyvinyl formal, polysulfone, polyacrylamide, polyamide, and chlorinated rubber, and organic photoconductive polymers such as poly-N-vinyl cal/hesol, polyvinylanotone, and polyvinylubidine.

Since the charge transport layer has a limit in its ability to transport charge carriers, it cannot be made as thick as necessary. Generally, the thickness is 5 to 30 microns, but the preferred range is 8 to 20 microns. It is micron. When forming the charge transport layer by coating, an appropriate coating method as described above can be used.

A photosensitive layer having such a laminated structure of a charge generation layer and a charge transport layer is provided on a substrate having a conductive layer, ie, a conductive support L. Examples of the substrate having a conductive layer include those whose substrate itself is conductive, such as aluminum, aluminum alloy, copper, and zinc.

Stainless steel, vanadium, molybdenum, chromium.

Titanium, nickel, indium, gold and platinum can be used, as well as aluminum, aluminum alloys,
A substrate in which a plastic (e.g., carbon black, silver particles, etc.) is coated with a layer of indium oxide, tin oxide, indium oxide-tin oxide alloy, etc. by vacuum evaporation method is coated on the plastic together with a suitable binder; A substrate made of plastic or paper impregnated with conductive particles, a plastic containing a conductive polymer, etc. can be used.

A subbing layer with barrier markings and adhesive f@ can also be provided between the conductive layer and the photosensitive layer. The subbing layer is made of casein, polyvinyl alcohol, nitrocellulose, ethylene-acrylic acid copolymer, polyvinyl butyral, phenolic resin, polyamide (nylon 6, nylon 88.
nylon 81O5 copolymerized nylon, alkoxymethylated nylon, etc.).

It can be formed from polyurethane, gelatin, aluminum oxide, etc.

112 thickness of the undercoat layer is 0.1 micron to 40 micron,
Preferably, O71 to 3 microns is suitable.

When using a photoreceptor in which a conductive layer, a charge generation layer, and a charge transport layer are laminated in this order, and the charge transport material in the charge transport layer is an electron transport material, the surface of the charge transport layer should be aligned directly with the surface of the charge transport layer. f
When exposed to light after charging, electrons generated in the charge generation layer are injected into the charge transport layer in the exposed area, and then reach the surface and neutralize the positive charge, resulting in attenuation of the surface potential. Electrostatic contrast occurs between the exposed area and the exposed area. A visible image can be obtained by developing the electrostatic latent image thus formed with a negatively charged toner. This can be directly fixed, or the toner image can be transferred to paper, plastic film, etc. and then developed and fixed.

Alternatively, a method may be used in which the electrostatic latent image on the photoreceptor is transferred to an insulating layer of transfer paper, then developed and fixed. The type of developer, the developing method, and the fixing method may be any known ones or known methods, and are not limited to specific ones.

On the other hand, when the charge transporting material is made of a hole transporting material, the surface of the charge transporting layer is set to negative i1? When exposed to light after stripping W, the holes generated in the charge generation layer are injected into the charge transport layer in the exposed area, and then reach the surface and neutralize the negative charges, causing a decrease in surface potential and an unused layer. Electrostatic contrast occurs between the exposed area and the exposed area.

During development, it is necessary to use a positively charged toner, contrary to the case where an electron transport material is used.

The electrophotographic photoreceptor according to the present invention is susceptible to deterioration due to ultraviolet rays, ozone, etc., dirt from oil, etc., scratches from metal chips, etc., damage to the photoreceptor due to photoreceptor contact members such as developing members, transfer members, cleaning members, etc. A protective layer may be further provided on the charge generation layer or the charge transport layer for the purpose of preventing abrasion. In order to form an electrostatic latent image on this protective layer,
It is desirable that the surface resistivity is 19110 or more.

The protective layer used in the present invention is made of resin such as polyvinyl butyral, polyester, polycarbonate, acrylic resin, methacrylic resin, nylon, polyimide, polyarylate, polyurethane, styrene-butadiene copolymer, styrene-acrylic acid copolymer, styrene-acrylonitrile copolymer, etc. It can be formed by applying a solution dissolved in an appropriate organic solvent onto the photosensitive layer and drying it.

Moreover, additives such as ultraviolet absorbers can be added to the resin liquid. At this time, the thickness of the protective layer is generally 0.05~
20 microns, particularly preferably in the range 0.2 to 5 microns.

Hereinafter, the present invention will be explained according to examples.

Example 1 An ammonia aqueous solution of casein (11.2 g of casein, 1 g of 28% ammonia water, 222 mM of water) was coated on an aluminum cylinder by a coating method, and dried to form a subbing layer with a coating weight of 1 and 0 g/nf. was formed.

Next, 1 part by weight of a charge generating material represented by formula (I), 1 part by weight of butyral resin (S-LEC BM-2: manufactured by Sekisui Chemical ■)
Parts by weight and 30 parts by weight of isopropyl alcohol were dispersed for 4 hours using a ball mill disperser.

This dispersion was applied onto the previously formed subbing layer by a dip coating method and dried to form a charge generation layer. The film thickness at this time was o, 3g. Next, Table 117) Compound N
o 1 part by weight of the hydrazone compound of (1), polysulfone resin (P1700: manufactured by Union Carbide Co., Ltd.) lf
Part fli and 6 parts by weight of monochlorobenzene were mixed and dissolved by stirring with a stirrer.

This liquid was applied onto the charge generation layer by dip coating and dried to form a charge transport layer. The film thickness at this time is 1
It was 3JL.

A corona discharge of 15 KV was applied to the photoreceptor thus prepared. The surface potential at this time was measured (initial potential vO),
Furthermore, the surface potential of this photoreceptor was measured after it was left in a dark place for 5 seconds (dark decay v5).The sensitivity was determined by the exposure ffl (E
Evaluation was made by measuring l/21ux*5ec).

These results were as follows.

Vo: -590 volts V5: -580 volts El/2: 5.7JLux*sec Example 2
~5 Compound No. (1) used in Example 1 Except that the compounds shown in Table 1 were used in place of the second compound.

A photoreceptor was prepared in exactly the same manner as in Example 1, and the characteristics of this photoreceptor were measured. These results are shown in Table 2.

Table 2 Example Compound No We(-V) V5(-V)
El/2 look U! Φ5ec 2 2 5905805°5 3 3 5955856.1 4 4 6005905.9 5 5 6105956.4 Comparative Examples 1 to 6 The charge transport substances shown in Table 3 were used instead of the hydrazone compound used in Example 1. A photoreceptor was produced in exactly the same manner. The charging characteristics are shown in Table 4.

Table 3 Comparative example Comparative charge Comparative charge transport material structural formula Comparative example
Comparative charge Comparative charge transport material structural formula transport material behavior table 4 Comparative example Comparative charge Vo (-V) V5 (-V)
El/2 transport substance NO1ux * 5ea 1 1 5805557.8 2 2 5705457.4 3 3 5705507.7 4 4 590575 B, 6 5 5 5905707.5 6 6 5805507.9 As is clear from the results of Examples and Comparative Examples In addition, it can be seen that the laminated photoreceptor of the present invention has extremely high sensitivity compared to the comparative examples of photoreceptor movement 1 to positive and 6. Furthermore, 4 m copies of the photoreceptors of Examples 1 to 3 (NP-1502
：+Y)Y Co., Ltd.) to produce an image for 20
Repeated 000 times. As a result, both photoreceptors had 200
Good quality images were obtained even after 00 collapses. As a result, it can be seen that the photoreceptor of the present invention has extremely excellent durability.

[9. Bright effect] As is clear from the above, the present invention uses a specific polycyclic non-based pigment as a charge-generating material in the charge-generating layer and a specific hydrazone-based compound in the charge-transporting layer, thereby improving the conventional technology. Laminated y with extremely high sensitivity compared to other products! X! This made it possible to provide an electrophotographic photoreceptor.

Claims (2)

[Claims] (1) In a laminated photographic photoreceptor in which a charge generation layer and a charge transport layer are provided on a conductive support, the charge generation layer has the formula (
I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼It consists of a layer containing a polycyclic quinone pigment represented by (I), and the charge transport layer is the general formula (II).▲There are mathematical formulas, chemical formulas, tables, etc.▼(II ) (In the formula, R_1 and R_2 represent a hydrogen atom, a halogen atom, a substituted or substituted alkyl group, an alkoxy group, a substituted or unsubstituted aryloxy group, or a substituted amino group, provided that at least one of R_1 and R_2 is a substituted amino group or an alkoxy group, R_3 and R_4 are substituted or unsubstituted alkyl groups, or substituted or unsubstituted aryl groups, provided that at least one of R_3 and R_4 is substituted or unsubstituted. is an aryl group, and R_3 and R_4 may form a nitrogen-containing heterocycle, R_5, R_6, R_7, and R
_8 represents a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group, an alkoxy group, a substituted or unsubstituted aryloxy group, or a substituted amino group, and n represents 0 or 1. ) An electrophotographic photoreceptor comprising a layer containing a hydrazone compound represented by: (2) The electrophotographic photoreceptor according to claim 1, wherein the charge generation layer contains a hydrazone compound represented by formula (II).