JPS6191664A - Photoconductive film and electrophotographic sensitive body using it - Google Patents

Abstract

PURPOSE:To obtain an electrophotographic sensitive body high in sensitivity by forming a photoconductive film contg. a specified malotropocyanine compd. on a conductive substrate to form a photosensitive layer. CONSTITUTION:The photosensitive body enhance in sensitivity and durability, and suitable for a laser beam printer, an electrophotographic copying machine, etc., is obtained by vapor depositing the compd. on the conductive substrate, dispersing it into a binder and forming photoconductive film, and preferably, incorporating it in an electrostatic charge generating layer and forming a charge transfer layer on this layer to form a laminate photosensitive layer. The compd. is represented by the formula in which n is 0, 1, or 2; each of R1-R6 is optionally substd. alkyl, aralkyl, aryl, or adjacent 2 groups of them may form a condensed ring with a tropilium ring.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a novel photoconductive coating and a highly sensitive electrophotographic 1c photoreceptor using the same.

BACKGROUND OF THE INVENTION Conventionally, there have been numerous publications regarding pigments and dyes that exhibit photoconductivity.

For example, “RCA Review” Vol. 25
, P., 415-P, 419 (1962, 9), two publications were made on the photoconductivity of phthalocyanine pigments, and electrophotographic photoreceptors using this phthalocyanine pigment were published in U.S. Pat. No. 5,597,086 and U.S. Pat. Patent No. 38
This is shown in the L6118 publication. In addition, examples of organic semiconductors used in electrophotographic photoreceptors include US Pat. No. 4,315,983, US Pat. No. 4,327,169, and "RCPePLch Disclosure"2.
051.7 (1981, 5)
IJium dye, methine squaric acid dye shown in US Pat. No. 3,824,099, US IF'!
jIIFf No. 38913084, US Patent No. 42
Examples include disazo pigments disclosed in Japanese Patent No. 51613 and the like.

Such organic semiconductors are easier to synthesize than unsuitable semi-compounds, and can be synthesized as compounds that have photoconductivity for light in the required wavelength range.
An electrophotographic photoreceptor in which a conductive film is formed on a conductive support has the advantage of improved color sensitivity, but only a few of them are practical in terms of sensitivity and durability.

Problems to be Solved by the Invention The first object of the present invention is to completely rupture the 'LLL-induced membrane rupture in a highly sensitive photoreceptor.

A second object of the present invention is to provide an electrophotographic photoreceptor using a highly sensitive photoconductive coating.

A third object of the present invention is to provide an electrophotographic photoreceptor suitable for electrophotographic copying machines.

Means for Solving the Problems The objects of the present invention are achieved by malotropocyanin represented by the following general formula (1).

That is, the present invention comprises an electrophotographic photoreceptor characterized by being provided with a photoconductive coating containing malotropocyanine represented by the following general formula [I] and a photosensitive JH having the coating.

In the general formula, n represents 0.1 or 2, and R1 to R6 are alkyl groups such as methyl, ethyl, and propyl, aralkyl groups such as benzyl and phenethyl, and aryl groups such as phenyl and naphthyl. , halogen atoms such as chlorine, bromine, and iodine, cyano groups, nitro groups, alkoxy groups such as methoxy, ethoxy, and propoxy, substituted amines such as dimethylamino, diethylamino, diphenylamino, dibenzylamino, morpholino, bilysine, and pyrrolidino. It may be substituted with a group, a hydroxyl group, etc.

Alternatively, it represents a residue in which two adjacent groups form a fused ring with tropylium a.

Next, a general method for producing malotropocyanin used in the present invention will be described.

The compound represented by the general formula (1) generally has the reaction formula It can be synthesized by

The symbols in the formula have the same meanings as those in the general formula [11].

Details of the synthesis method can be found in Chem, Ber, 97, 2050
~2065 (1964).

The malotropocyanin compounds and specific examples used in the present invention are listed below.

In malotropocyanine compounds, the absorption shifts to longer wavelengths as the methine chain lengthens.

The absorption spectrum of representative examples of the above compounds is shown in the drawings.

The coating containing malotropocyanine described above exhibits photoconductivity, and therefore can be used in the photosensitive layer of the electrophotographic photoreceptor described below.

That is, in a specific example of the present invention, the electrophotographic photoreceptor is formed by forming a film of the above-mentioned malotropocyanine on the conductive support σ by vacuum evaporation, or by forming a film by dispersing it in a suitable binder. can be prepared.

In a preferred embodiment of the present invention, the photoconductive coating described above can be applied as a charge generation layer in an electrophotographic photoreceptor in which the photosensitive layer is functionally separated into a charge generation layer and a charge transport layer.

The charge generation layer contains as much of the above-mentioned photoconductive compound as possible in order to obtain sufficient absorbance, and is a thin film layer, for example, 5μ or less, in order to shorten the range of the generated charge carriers. Preferably, the thin film layer has a thickness of 0.01 to 1 μm. This means that most of the incident light is absorbed by the charge generation layer to generate a large number of charge carriers, and that the generated charge carriers are not deactivated by recombination or trapping (K) in the charge transport layer. This is due to the need to inject.

The charge generation layer can be formed by dispersing the above-mentioned compound in a suitable binder and coating it on the substrate, or can be obtained by forming a vapor deposited film using a vacuum vapor deposition apparatus. Bi?5 used when forming the charge generation layer by coating? The goo can be selected from a wide variety of insulating resins and organic photoconductive polymers such as poly-N-vinylcarbazole, polyvinylanthracene and polyvinylpyrene.

Preferably polyvinyl butyral, polyarylate (
polycarbonate, polyester, phenoxy resin, polyvinyl acetate, acrylic resin, polyacrylamide, polyamide, polyvinylpyridine, cellulose resin, urethane resin, epoxy resin, casein, polyvinyl alcohol,
Examples include insulating resins such as polyvinylpyrrolidone. The resin contained in the charge generation layer is preferably 80% by weight or less, preferably 40% by weight or less.

The solvent that dissolves these resins varies depending on the type of resin, and is preferably selected from those that do not dissolve the charge transport layer or undercoat layer described below. Specific organic solvents include alcohols such as methanol, ethanol and isopropanol; ketones such as acetone, methyl ethyl ketone and cyclohexanone; amides such as N,N-dimethylformamide and N,N-dimethylacetamide;
Sulfoxides such as dimethyl sulfoxide, ethers of tetrahydrone, dioxane, ethylene glycol monomethyl ether, esters such as methyl acetate and ethyl acetate, aliphatics such as chloroform, methylene chloride, dichloroethylene, carbon tetrachloride, trichlorethylene, etc. Halogenated hydrocarbons or aromatic compounds such as benzene, toluene, xylene, ligroin, monochlorobenzene, and dichlorobenzenato can be used.

Coating can be performed using a coating method such as a dip coating method, a spray coating method, a spinner coating method, a bead coating method, a Meyer bar coating method, a blade coating method, a roller coating method, or a curtain coating method. For drying, it is preferable to dry to the touch at room temperature and then heat dry. Heat drying at a temperature of 30L to 200℃ for 5 minutes or more
It can be carried out stationary or under blown air for a time in the range of 2 hours.

The charge transport layer is electrically connected to the charge generation layer described above, and has the function of receiving and taking charge carriers injected from the charge generation layer in the presence of an electric field, and transporting these charge carriers to the surface. have. In this case, this charge transport layer may be laminated on top of (or under) the charge generation layer.However, if the charge generation layer is the top layer, the coating film may be scratched during repeated use. It is desirable that the charge transport layer is laminated on the charge generation layer.

The substance that transports charge in the charge transport layer (hereinafter simply referred to as charge transport material) is preferably substantially insensitive to the wavelength range of electromagnetic waves to which the charge generation layer is sensitive. The term "electromagnetic waves" used herein includes a broad definition of "light rays" including r-rays, X-rays, ultraviolet rays, visible light, near-infrared rays, infrared rays, far-infrared gonads, 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.

Charge-transporting substances include electron-transporting substances and hole-transporting substances, and electron-transporting substances include chloranil, bromoanil, tetracyanoethylene, tetracyanoquinodimethane, and 2,4,7-trinitro-9-fluorenone. ,
2,4,5.7-titranito-4-9-fluorenone, 2
, 4.7-)nitro-9-dicyanomethylenefluorenone, 2.4,5.7-teto-2-nitroxanthone, 2
, 4,8-trinidrothioxanthone and other electron-withdrawing substances, and polymerized products of these electron-withdrawing substances.

Examples of the hole-transporting substance include pyrene, N-:r-f-carbazole, N-isopropylcarbazole, N-methyl-N-phenylhydrazino-3-methylidene-9-ethylcarbazole, and N,N-diphenylhydra. Jino-3
-Methylidene-9-ethylcarbasol, N,N-diphenylhydrazino-3-methylidene-10-ethylphenothiazine, N,N-diphenylhydrazino-3=methylidene-10-ethylphenoxazine, P-diethylaminobenzaldehyde N , N-diphenylhydrazone, P-diethylaminobenzaldehyde-N-α-su7
Chi-N-phenylhydrazone, P-pyrrolidinobenzaldehyde-N, N-diphenylhydrazone, 1,3.
3-) IJ me? Ruindrenine-ω-aldehyde-
Hydrazones such as N,N-diphenylhydrazone, P-diethylbenzaldehyde-5-methylbenzthiazolinone-2-hydrazone, 2,5-bis-(P-diethylaminophenyl)-1,3,4-o'xadiazole , 1-phenyl-3-(P-diethylaminostyryl)
-5-(P-diethylaminophenyl)pyrazoline, 1
-, (quinolyl(2)) -5-(p-diethylaminostyryl)-5-(p-diethylaminophenyl)pyrazoline, 1-[pyridyl(2)) -5-(p-diethylaminostyryl)-5-(P -diethylaminophenyl]pyrazoline, 1-(6-medoxybilidyl(
2) )-3-CP-diethylaminostyryl)-5
-(P-diethylaminophenyl)pyrazoline, 1-[
Pyridyl (3) ) -3-(P-diethylaminostyryl)-5-(P-diethylaminophenylmbirazoline, 1-[lepidyl (2) )-3-(P-diethylaminostyryl)-5-(P-diethylaminostyryl) phenyl]pyrazoline, 1-[pyridyl (2) ) -3-(
p-diethylaminostyryl)-4-methyl-5-(P
-diethylaminophenyl)pyrazoline, 1-[pyridyl(2)] -3-(α-methyl-P-diethylaminostyryl-5-(P-diethylaminophenyl)hirazoline, 1-phenyl-3-(P-diethylaminosteryl) Pyrazolines such as -4-methyl-5-(p-diethylaminophenyl)pyrazoline, 1-phenyl-3-(α-benzyl-P-diethylaminostyryl)-5-(P-diethylaminophenyl)pyrazoline, spiropyrazoline, 2- (P-diethylaminostyryl)-
6-Dinithylaminobenzoic acid? 7'-#, 2-CP
Oxazole compounds such as -diethylaminophenyl)-4-(P-dimethylaminophenyl)-5-(2-chlorophenyl)oxazole, thiazole compounds such as 2-(p-diethylaminostyryl)-6-dinithylaminobenzothiazole , bis(4-diethylamino-2
-Triarylmethane compounds such as methylphenylcuphenylmethane, 1,1-bis(4-N,N-diethylamino-2-methylphenyl)hebutane, 1,1,2.
Polyarylalkanes such as 2-tetrakis(4-N,N-dimethylamine-2-methylphenyl)ethane, triphenylamine, poly-N-vinylcarbazole, polyvinylpyrene, polyvinylanthracene, polyvinylacridine, poly-9- vinylphenylanthracene,
Examples include helene-formaldehyde resin, ethylcarbazole formaldehyde resin, etc.

In addition to these organic charge transport materials, inorganic materials such as selenium, selenium-tellurium amorphous silicon, and cadmium sulfide can also be used.

Further, these charge transport substances can be used in one form or in combination of two or more types.

When the charge transport material does not have film-forming properties, a film can be formed by selecting an appropriate binder. Examples of resins that can be used as binders include acrylic resin,
polyarylate, polyester, polycarbonate, polystyrene, acrylonitrile-styrene copolymer,
Acrylonitrile-butadiene copolymer, polyvinyl butyral, polyvinyl formal, pho-17 sulfone,
Examples include insulating resins such as polyacrylamide, polyamide, and chlorinated rubber, and organic photoconductive polymers such as poly-N-vinylcarbazole, polyvinylanthracene, and polyvinylpyrene.

Since the charge transport layer has a limit in its ability to transport charge carriers, it cannot be made thicker than necessary. Generally, it is 5 to 30μ, but the preferred range is 8 to 20μ.
It is. 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. Examples of substrates having a conductive layer include those in which the substrate itself is conductive;
For example, aluminum, aluminum alloy, copper, zinc, stainless steel, vanadium, molybdenum, chromium, titanium,
Nickel, indium, gold, platinum, etc. can be used, and plastics (for example, polyethylene , polypropylene, polyvinyl chloride, polyethylene terephthalate, acrylic resin,
(polyfluorinated ethylene, etc.), 4'tj, a substrate made of plastic coated with conductive particles (e.g. carbon blank, silver particles, etc.) together with a suitable binder, a substrate made of plastic or paper impregnated with conductive particles, or a conductive polymer. It is possible to use plastics having the following characteristics.

A subbing layer having barrier and adhesive functions can also be provided between the conductive layer and the photosensitive layer. The subbing layer is casein,
Polyvinyl alcohol, nitrocellulose, ethylene-
Acrylic acid copolymer, polyamide (nylon 6, nylon 66, nylon 610, copolymerized nylon, alkoxymethylated nylon, etc.), polyurethane, gelatin,
It can be formed from aluminum oxide, etc.

The thickness of the subbing layer is [L1~5μ, preferably 115~3μ]
μ is appropriate.

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 is an electron transport material, the surface of the charge transport layer must be positively charged, and exposure after charging is required. Then, in the exposed area, electrons generated in the charge generation layer are injected into the charge transport layer, which then neutralizes the positive charges that reach the surface, causing a decrease in surface potential and creating an electrostatic contrast with the unexposed area. .

Shizuka-X was created like this! A visible image is obtained by developing the image with a negatively charged toner. Either fix this directly, or transfer the toner image to paper or plastic film, etc.
It will take a long time to become established.

Alternatively, a method may be used in which the electrostatic latent image on the photoreceptor is transferred onto 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 transport material consists of a hole transport material, the surface of the charge transport layer must be negatively charged, and when exposed to light after charging, holes generated in the charge generation layer are injected into the charge transport layer in the exposed area. After that, it reaches the surface and neutralizes the negative charge, causing an attenuation of the surface potential and creating an electrostatic contrast between it and the unexposed area. During development, it is necessary to use a positively charged toner, contrary to the case where an electron transporting substance is used.

Furthermore, it is also possible to form a single-layer type photoreceptor in which malotropocyanine is dispersed in the binder resin.

Further, in another specific example of the present invention, the above-mentioned hydrazones,
Organic photoconductive substances such as pyrazolines, oxazoles, thiazoles, triarylmethanes, polyarynylalkanes, triphenylamine, poly-N-vinylcarbazoles, and inorganic photoconductive substances such as zinc oxide, cadmium sulfide, and selenium. The photosensitive film may contain the above-mentioned malotropocyanin as a sensitizer for a sexual substance. This photosensitive film is formed by coating these photoconductive substances and the above-mentioned malotropocyanine compound together with a binder.

Further, as another specific example of the present invention, JP-A No. 49-9t64
It can also be used as a type of photoreceptor in which a charge-generating paulownia material is dispersed in a charge-transfer complex as disclosed in Publication No. 8 (Photoconductive Part@).

All photoreceptors contain at least one kind of malotropocyanin selected from the compounds represented by the general formula (1), and if necessary, other photoconductive pigments or dyes with different light absorptions are used in combination. By doing so, it is possible to increase the sensitivity of this photoreceptor or to prepare it as a panchromatic photoreceptor.

The electrophotographic photoreceptor of the present invention can be widely used not only in electrophotographic copying machines but also in electrophotographic applications such as laser beam printers, LID printers, and CR'r printers.

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

Examples 1 to 11: An ammonia aqueous solution of casein (11.2 f of casein, 1 f of ammonia water related to 2B, 222 m of water) was applied onto an aluminum plate using a Mayer bar so that the film thickness after drying was 1.0μ, Dry.

Next, butyral resin (butyralization degree 63 mol%) 2
To a solution prepared by dissolving f in 95 txt of isopropyl alcohol, 11 types of malotropocyanin 52 listed in the table below were added to prepare 11 types of coating liquids.

After dispersing each coating solution in a sand mill for 5 hours, each coating solution was applied onto the above casein undercoat layer using a Mayer bar so that the film thickness after drying was 0.1μ, and dried to form a charge generation layer. I let it happen.

Next, hydrazone compound 52 of the structural formula and polymethyl methacrylate resin (number average molecular weight 100,000) 5f were added to benzene 70af! This was applied onto the charge generation layer using Mayer Par so that the film thickness after drying was 12 μm, and dried to form a tli transport layer.

The 11-glaze electrophotographic photoreceptor thus prepared was statically corona-charged to -5 at '7 using Kawaguchi Denki U's Seiden Kumisha Testing Equipment Model SF-428, and held in a dark place for 1 second. Thereafter, it was exposed to light for 4 seconds at an illuminance of 51 uX, and the charging characteristics were examined.

The charging characteristics are the initial charging potential (To) and the amount of light exposure required to attenuate the potential when darkened for 1 second (-
] was measured. The results are shown in Table 1. Also, 20 l
The residual potential after ux·θθCm light was expressed in vR.

Table 1 Example 12 Polyester resin (manufactured by Toyobo Co., Ltd., Byron 200) 5
f and 1-[virigirou (2)) -3-(4-N,
After dissolving N-diethylaminostyryl J-5-(4-N,N-diethylaminephenyl)pyrazoline 5t in methyl ethyl ketone 80-, the aforementioned malotropocyanin 42 1. After adding and dispersing Of, it was coated on a polyester film coated with aluminum and dried, resulting in a dry film thickness of 13 μm.
A photoreceptor having a photosensitive layer was prepared.

The characteristics of this photoreceptor were measured by the same method as in Example 1, including the initial charging potential (Vn) and the amount of light exposure (Kl, %) required to attenuate the charging potential to 1 hour after dark decaying for 1 second. , were as follows.

However, the charging polarity was O.

Vo: +5aov ] 1CV2: 5.01u>:5eec Example 13 Poly-N-vinylcarbazole 12 and the above-mentioned malotropocyanin A35 1.2-' were added to chloroethane 10F and thoroughly stirred. The coating liquid thus prepared was applied onto a polyethylene terephthalate film on which aluminum was vapor-deposited using a doctor blade so that the dry film thickness was 15/J.

The charging characteristics of this photoreceptor were measured in the same manner as in Example 1. However, the charging polarity was O. The results are shown below.

vo: +560V IC1%, : 411uxaseaExample 14 The above malotropocyanin &
A photoreceptor was prepared in exactly the same manner as in Example except that No. 10 was used, and then the charging characteristics of this photoreceptor were measured. The results are shown below. However, the charging polarity was O.

Va: +5701 El: 4.81uxase.

Example 15 Fine particle zinc oxide (8azex 2000 manufactured by Sakai Chemical Co., Ltd.)
102, 4 tons of acrylic resin (Dyanal LROO9 manufactured by Mitsubishi Rayon ■), 10 f of toluene, and 110 η of the above-mentioned malotropocyanin A were thoroughly mixed in a ball mill, and the resulting coating solution was applied onto a polyethylene terephthalate film coated with aluminum vapor. The film was coated with a doctor blade to a dry film thickness of 21 μm and dried to prepare an electrophotographic photoreceptor.

When the spectral sensitivity of this electrophotographic photoreceptor was measured using spectrophotography using electrophotography, it was found that the photoreceptor of this example showed sensitivity on the longer wavelength side compared to the aforementioned zinc oxide coating that did not contain malotropocyanin. It turned out that it has.

Example 16 A polyvinyl alcohol film having a thickness of 1.1 μm was formed on the aluminum surface of an aluminum vapor-deposited polyethylene terephthalate film.

Next, the same malotropocyanin-containing coating solution as in Example 3 was applied to the previously formed polyvinyl alcohol layer using one ear perforation so that the film thickness after drying was α1μ.
It was dried to form a charge generation layer.

Next, 5 g of a pyrazoline compound with the structural formula and polyarylate resin (condensation polymer of bisphenol A and terephthalic acid-isophthalic acid)
A solution obtained by dissolving No. 51 in 70% of tetrahydrofuran was applied onto the charge generation layer so as to have a dry film thickness of 10 μm, and dried to form a charge transport layer.

The charging characteristics of the photoreceptor thus prepared were measured in the same manner as in the examples. The results are shown below.

VO: -590V E: 521ux-sea Example 17 An ammonia aqueous solution of casein was coated on an aluminum plate with a thickness of 100 μm and dried to form a subbing layer with a thickness of 1.1 μm.

Next, 2,4.7-) dinitro-9-fluorenone 5
t and poly-N-vinylcarbazole (number average molecular weight 30
0,000) 5f was dissolved in tetrahydro7rane70- to form a charge transfer complex compound.

This charge transfer complex compound and the above-mentioned malotropocyanine compound A31F were combined with a polyester resin (Byron: Toyobo! u
, ) 5 t was dissolved in 7° of tetrahydro7ran and dispersed. This dispersion was applied onto the undercoat layer so that the film thickness after drying was 12 μm, and dried. The charging characteristics of the photoreceptor thus prepared were measured in the same manner as in Example 1.

These results were as follows. However, the charging polarity was O.

vn,...550v BV2: 4.81ux-sea

[Brief explanation of drawings]

The absorption spectrum of an n-hexane solution of the malotropocyanine compound A1.2.3 used in the present invention is shown.

Claims (3)

[Claims] (1) A photoconductive film containing malotropocyanin represented by the following general formula [I]. ▲There are mathematical formulas, chemical formulas, tables, etc.▼ [I] In the formula, n represents an integer of 0, 1, or 2, and R_1 to R_6 are alkyl groups, aralkyl groups, or aryl groups that may have substituents, or adjacent The two groups shown above represent residues that form a fused ring with the tropylium ring. (2) An electrophotographic photoreceptor comprising a photosensitive layer having a photoconductive coating containing malotropocyanine represented by the following general formula [I] on a conductive support. ▲There are mathematical formulas, chemical formulas, tables, etc.▼ [I] In the formula, n represents an integer of 0, 1, or 2, and R_1 to R_6 are an alkyl group, an aralkyl group, or an aryl group that may have a substituent, or Indicates a residue in which two adjacent groups form a fused ring with the tropylium ring. (3) The photosensitive layer provided on the conductive support is a charge generating layer having a photoconductive coating containing at least malotropocyanine represented by the general formula [I] in claim 2, and a charge generating layer. The electrophotographic photoreceptor according to claim 2, wherein transport layers are sequentially laminated.