JPH0448224B2 - - Google Patents

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION FIELD The present invention relates to a novel photoconductive coating and a highly sensitive electrophotographic photoreceptor using the same. BACKGROUND ART Conventionally, pigments and dyes exhibiting photoconductivity have been published in numerous publications. For example, “RCA Review” Vol.23, P.413～
P.419 (September 1962), there was a presentation on the photoconductivity of phthalocyanine pigments, and electrophotographic photoreceptors using this phthalocyanine pigment were shown in U.S. Pat. No. 3,397,086, U.S. Pat. No. 3,816,118, etc. ing. In addition, as organic semiconductors used in electrophotographic photoreceptors, for example, US Pat.
4315983, U.S. Patent No. 4327169 and “
Pyrylium dyes shown in Reseach Disclosure''20517 (May 1981), methine squaritate dyes shown in US Patent No. 3824099,
Examples include disazo pigments disclosed in US Pat. No. 3,898,084, US Pat. No. 4,251,613, and the like. Such organic semiconductors are easier to synthesize than inorganic semiconductors, and can be synthesized as compounds that have photoconductivity for light in the required wavelength range. An electrophotographic photoreceptor 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 A first object of the present invention is to provide a highly sensitive photoconductive coating. 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 and Effects for Solving the Problems The objects of the present invention are achieved by a tropylium salt compound represented by the following general formula (). That is, the present invention comprises an electrophotographic photoreceptor characterized by being provided with a photoconductive coating containing a tropylium salt compound represented by the following general formula () and a photosensitive layer having the coating. general formula In the formula, m represents an integer selected from 0, 1, 2, and 3, and R ₁ to R ₆ are alkyl groups such as methyl, ethyl, and propyl, aralkyl groups such as benzyl and phenethyl, and aryl groups such as phenyl and naphthyl. These groups include halogen atoms such as chlorine, bromine, and iodine,
It may be substituted with a cyano group, a nitro group, an alkoxy group such as methoxy, ethoxy, propoxy, a substituted amino group such as dimethylamino, diethylamino, diphenylamino, dibenzylamino, morpholino, piperidino, pyrrolidino, or a hydroxyl group. Further, two adjacent groups selected from R ₁ to _{R 6} represent a residue that forms a condensed ring with the tropylium ring. X is

【formula】

[Formula] or

[Formula] is shown. However, R ₇ and R ₈ are benzene, naphthalene, mantrasenpyrene, which may have a substituent,
It represents an aromatic hydrocarbon group derived from fluorene, etc., or a heterocyclic group derived from phenothiazine, phenoxazine, carbazole, indole, pyrrole, furan, thiophene, dibenzofuran, acridine, etc. Substituents for aromatic hydrocarbon groups and heterocyclic groups include lower alkyl groups such as methyl, ethyl, propyl, and butyl, alkoxy groups such as methoxy, ethoxy, propoxy, and butoxy, aryloxy groups such as phenoxy, methyl mercapto, and ethyl. Alkylcapto groups such as mercapto, amino groups, dialkylamino groups such as dimethylamino, diethylamino, dipropylamino, dibutylamino, dialkylamino groups such as dibenzylamino, diarylamino groups such as diphenylamino, methylphenylamino, ethyl Alkylaryl amino groups such as phenylamino, cyanoethylphenylamino, chloroethylphenylamino, benzylmethylamino,
Alkylaralkylamino groups such as benzylretylamino and benzylcyanoethylamino, aralkylarylamino groups such as benzylphenylamino, cyclic amino groups such as piperidino, morpholino, and pyrrolidino, and β such as P-dimethylaminostyryl.
Examples include -arylethylene group, arylazo group such as P-dimethylaminophenylazo, and halogen atoms such as chlorine, bromine, and iodine. n represents 0 or 1. Y is -O-, -S-, -Se-, -Te-
or NR ₁₅ . _R15 is an alkyl group such as methyl, ethyl, propyl, butyl, 2-hydroxyethyl, 2-methoxyethyl, 2-ethoxyethyl, 3-hydroxypropyl, 3-methoxypropyl, 3-ethoxypropyl, 3-chloropropyl, Substituted alkyl groups such as 3-bromopropyl and 3-carboxypropyl; substituted or unsubstituted aralkyl groups such as benzyl, phenethyl, α-naphthylmethylchlorobenzyl, and bromobenzyl; substituted and unsubstituted aralkyl groups such as phenyl, tolyl, and naphthylnitrophenyl; Indicates an unsubstituted aryl group, etc. In the formula, Z is pyridine, thiazoline, thiazole, benzthiazole, naphthothiazole, oxazoline, oxazole, benzoxazole,
naphthoxazole, imidazoline, imidazole, benzimidazole, naphthoimidazole,
benzselenazole, quinoline, isoquinoline,
Indole, oxadiazole, thiadiazole, pyrylium, benzpyrylium, naphtopyrylium, and heterocycles in which oxygen is substituted with S, Se, Te, and in rings such as benzdithylium and naphthodithyllium, N-R ₁₅ or - O-,-
Indicates a residue forming a heterocycle containing S-, -Se-, -Te-, and such a heterocycle includes halogen atoms such as chlorine, bromine, iodine, and fluorine, methyl, ethyl,
It may be substituted with an alkyl group such as propyl or butyl, an alkoxy group such as methoxy, ethoxy, propoxy or butoxy, a nitro group, or an aryl group such as phenyl or tolyl. Hydrogen attached to a carbon atom in a chain connecting two tropylium rings or a tropylium ring and a heterocycle may be substituted with a functional group, and examples of the substituent (R ₁₆ ) include halogen atoms such as chlorine and bromine, and cyano groups. , alkyl groups such as methyl, ethyl, and propyl; alkyl groups such as methoxy, ethoxy, and propoxy; alkyl mercapto groups such as methyl mercapto, ethyl mercapto, and butyl mercapto; and aryl groups such as phenyl. R ₉ to _{R 14} have the same meanings as R ₁ to _{R 6} in general formula (). Next, a general method for producing the tropylium salt compound used in the present invention will be described. X in general formula () is

The compound represented by the formula is Synthesized by [A] or [B]. Regarding this method, see Chem.Ber. 97 , 1590-1598 (1964)
The description is detailed. X in general formula () is

[Expression] If Kuha

The compound represented by the formula is generally synthesized according to the following reaction formula. Reaction formula [D], [E]

instead of [expression] If used, the corresponding pentamethine and heptamethine dyes can be obtained. Publicly known documents regarding these synthetic methods include
Angew.Chem. 75 344 (1963), and the general manufacturing method for cyanine dyes can be applied. The symbols in each reaction have the same meaning as the symbols in general formula (). Specific examples of the tropylium chloride compounds used in the present invention are listed below. The coating containing the tropylium salt compound described above exhibits photoconductivity and can therefore be used in the photosensitive layer of the electrophotographic photoreceptor described below. That is, in a specific example of the present invention, an electrophotographic photoreceptor is formed by forming a film of the above-mentioned tropylium salt compound on a conductive support by vacuum evaporation, or by dispersing it in a suitable binder and forming a film. It 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
A thin film layer having a thickness of 0.01 to 1 μm is preferable. This means that most of the incident light is absorbed by the charge generation layer, generating many charge carriers, and that the generated charge carriers are not deactivated by recombination or trapping, but are transferred to the charge transport layer. This is due to the need for injection. The charge generation layer can be formed by dispersing the above-mentioned compound in a suitable binder and coating it on the substrate, or it can be obtained by forming a vapor deposited film using a vacuum vapor deposition apparatus. . The binder that can be used when forming the charge generation layer by coating can be selected from a wide range of insulating resins.
It can also be selected from organic photoconductive polymers such as poly-N-vinylcarbazole, polyvinylanthracene and polyvinylpyrene. Preferably, polyvinyl butyral, polyarylate (condensation polymer of bisphenol A and phthalic acid, etc.), polycarbonate, polyester, phenoxy resin, polyvinyl acetate, acrylic resin, polyacrylamide,
Polyamide, polyvinylpyridine, cellulose resin, urethane resin, epoxy resin, casein,
Examples include insulating resins such as polyvinyl alcohol and polyvinylpyrrolidone. The resin contained in the charge generation layer is suitably 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 the underlayer described below. Specific organic solvents include alcohols such as methanol, ethanol, and isopropanol, ketones such as acetone, methyl ethyl ketone, and cyclohexanone, N,N-dimethylformamide,
Amides such as 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, aliphatic halogens such as chloroform, methylene chloride, dichloroethylene, carbon tetrachloride, and trichloroethylene. Hydrocarbons or aromatics such as benzene, toluene, xylene, ligroin, monochlorobenzene, dichlorobenzene, etc. can be used. Coating can be carried out using coating methods such as dip coating, spray coating, spinner coating, bead coating, Meyer bar coating, blade coating, roller coating, and curtain coating. For drying, it is preferable to dry to the touch at room temperature and then heat dry. Heat drying at a temperature of 30℃ to 200℃ for 5 minutes to 2
It can be carried out stationary or under blown air for a period of time within a range of hours. The charge transport layer is electrically connected to the charge generation layer described above, and has the function of receiving charge carriers injected from the charge generation layer in the presence of an electric field and transporting these charge carriers to the surface. ing. At this time, this charge transport layer may be laminated on or under the charge generation layer. However, if the charge generation layer is the uppermost layer, the coating may be scratched during repeated use, causing a change in sensitivity, so it is desirable that the charge transport layer be laminated on the charge generation layer. 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 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" that includes gamma rays, X-rays, ultraviolet rays, visible light, near infrared rays, infrared 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 trap each other, resulting in a decrease in sensitivity. Charge transport substances include electron transport substances and hole transport substances, and electron transport substances include chloranil, bromoanil, tetracyanoethylene, tetracyanoquinodimethane, and 2,4,7-trinitro-9-fluorenone. , 2, 4, 5, 7-
Tetranitro-9-fluorenone, 2,4,7-
trinitro-9-dicyanomethylenefluorenone, 2,4,5,7-tetranitroxanthone,
Examples include electron-withdrawing substances such as 2,4,8-trinitrothioxanthone, and polymerization of these electron-withdrawing substances. Examples of hole-transporting substances include pyrene, N-ethylcarbazole, N-isopropylcarbazole,
N-Methyl-N-phenylhydrazino-3-methylidene-9-ethylcarbazole, N,N-diphenylhydrazino-3-methylidene-9-ethylcarbazole, N,N-diphenylhydrazino-
3-methylidene-10-ethylphenothiazine,
N,N-diphenylhydrazino-3-methylidene-10-ethylphenoxazine, P-diethylaminobenzaldehyde-N,N-diphenylhydrazone, P-diethylaminobenzaldehyde-N
-α-Naphthyl-N-phenylhydrazone, P-
Pyrrolidinobenzaldehyde-N,N-diphenylhydrazone, 1,3,3-trimethylindolenine-ω-aldehyde-N,N-diphenylhydrazone, P-diethylbenzaldehyde-3-methylbenzthiazolinone-2-hydrazone hydrazones such as 2,5-bis(P-diethylaminophenyl)-1,3,4-oxadiazole, 1
-Phenyl-3-(P-diethylaminostyryl)
-5-(P-diethylaminophenyl)pyrazoline, 1-[quinolyl(2)]-3-(P-diethylaminostyryl)-5-(P-diethylaminophenyl)pyrazoline, 1-[pyridyl(2) ]-3-(P-
diethylaminostyryl)-5-(P-diethylaminophenyl)pyrazoline, 1-[6-methoxy-pyridyl(2)]-3-(P-diethylaminostyryl)-5-(P-diethylaminophenyl)pyrazoline, 1- [Pyridyl(3)]-3-(P-diethylaminostyryl)-5-(P-diethylaminophenyl)pyrazoline, 1-[Lepidyl(2)]-3-(P-
diethylaminostyryl)-5-(P-diethylaminophenyl)pyrazoline, 1-[pyridyl(2)]-
3-(P-diethylaminostyryl-4-methyl-5-(P-diethylaminophenyl)pyrazoline, 1-[pyridyl(2)]-3-(α-methyl-P-
diethylaminostyryl)-5-(P-diethylaminophenyl)pyrazoline, 1-phenyl-3-
(P-diethylaminostyryl)-4-methyl-5
-(P-diethylaminophenyl)pyrazoline,
1-Phenyl-3-(α-benzyl-P-diethylaminostyryl)-5-(P-diethylaminophenyl)pyrazoline, spiropyrazoline and other pyrazolines, 2-(P-diethylaminostyryl)
-6-diethylaminobenzoxazole, 2-
Oxazole compounds such as (P-diethylaminophenyl)-4-(P-dimethylaminophenyl)-5-(2-chlorophenyl)oxazole, 2
Thiazole compounds such as -(P-diethylaminostyryl)-6-diethylaminobenzothiazole, triarylmethane compounds such as bis(4-diethylamino-2-methylphenyl)-phenylmethane, 1,1-bis(4-N,N -diethylamino-2-methylphenyl)heptane, 1,
Polyarylalkanes such as 1,2,2-tetrakis(4-N,N-dimethylamino-2-methylphenyl)ethane, triphenylamine, poly-
N-vinylcarbazole, polyvinylpyrene, polyvinylanthracene, polyvinylacridine,
Examples include poly-9-vinylphenylanthracene, pyrene-formaldehyde resin, and ethylcarbazole formaldehyde resin. In addition to these organic charge transport materials, inorganic materials such as selenium, selenium-tellurium amorphous silicon, and cadmium sulfide can also be used. Moreover, these charge transport substances may be one or two types.
More than one species can be used in combination. When the charge transport material does not have film-forming properties,
A film can be formed by selecting an appropriate binder. Resins that can be used as binders are:
For example, insulating resins such as acrylic resin, polyarylate, polyester, polycarbonate, polystyrene, acrylonitrile-styrene copolymer, acrylonitrile-butadiene copolymer, polyvinyl butyral, polyvinyl formal, polysulfone, polyacrylamide, polyamide, chlorinated rubber, or poly-N- Mention may be made of organic photoconductive polymers such as vinylcarbazole, polyvinylanthracene, 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 5-30μ, but the preferred range is 8-20μ. 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. As the substrate having the conductive layer, materials that are themselves conductive can be used, such as aluminum, aluminum alloy, copper, zinc, stainless steel, vanadium, molybdenum, chromium, titanium, nickel, indium, gold, and platinum. In addition, plastics (such as polyethylene, polypropylene, polyvinyl chloride, polyethylene terephthalate, acrylic, resin, polyethylene fluoride, etc.), conductive particles (e.g. carbon black,
A substrate made of plastic coated with silver particles (silver particles, etc.) 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 having barrier and adhesive functions can also be provided between the conductive layer and the photosensitive layer. The undercoat layer may be made of casein, polyvinyl alcohol, nitrocellulose, ethylene-acrylic acid copolymer, polyamide (nylon 6, nylon 66, nylon 610, copolymerized nylon, alkoxymethylated nylon, etc.), polyurethane, gelatin, aluminum oxide, etc. It can be formed by The thickness of the undercoat layer is 0.1 to 5μ, preferably 0.5 to 3μ.
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 when exposed to light after charging, In the exposed area, electrons generated in the charge generation layer are injected into the charge transport layer, and then reach the surface and neutralize the positive charges, resulting in attenuation of the surface potential and an electrostatic contrast between the layer and the unexposed area. A visible image can be obtained by developing the electrostatic latent image thus formed with a negatively charged toner. Either fix this directly, or transfer the toner image to paper or plastic film, etc.
It can be developed and fixed. 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 is made of a hole transport material, it is necessary to charge the charge transport surface negatively, 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. Thereafter, it reaches the surface and neutralizes the negative charge, causing a decrease in surface potential and creating an electrostatic contrast with 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 a tropylium salt compound is dispersed in the binder resin. In another specific example of the present invention, organic photoconductive materials such as the aforementioned hydrazones, pyrazolines, oxazoles, thiazoles, triarylmethanes, polyarylalkanes, triphenylamines, poly-N-vinylcarbazoles, etc. The photosensitive coating may contain the above-mentioned tropylium salt compound as a sensitizer for photoconductive substances and inorganic photoconductive substances such as zinc oxide, cadmium sulfide, and selenium. This photosensitive film is formed by coating these photoconductive substances and the above-mentioned tropylium salt compound together with a binder. Further, as another specific example of the present invention, JP-A-49-
It can also be used as a type of photoreceptor in which a charge generating material is dispersed in a charge transfer complex as disclosed in Japanese Patent No. 91648 (photoconductive member). Each photoreceptor contains at least one kind of tropylium salt compound selected from the compounds represented by the general formula (), and if necessary, other photoconductive pigments or dyes with different light absorptions are used in combination. By increasing the sensitivity of this photoreceptor,
Alternatively, it is also possible to prepare a panchromatic photoreceptor. The electrophotographic photoreceptor of the present invention can be used not only for electrophotographic copying machines but also for laser beam printers,
It can also be widely used in electrophotographic applications such as LED printers and CRT printers. Hereinafter, the present invention will be explained with reference to examples. Examples 1 to 15 Ammonia aqueous solution of casein (11.2 g of casein, 1 g of 28% ammonia water, 222 ml of water) on an aluminum plate
was applied with a Mayer bar so that the film thickness after drying was 1.0μ, and dried. Next, 5 g of each of the 15 tropylium salt compounds listed in the table below were added to a solution of 2 g of butyral resin (butyralization degree: 63 mol%) dissolved in 95 ml of isopropyl alcohol to prepare 15 coating solutions. . After dispersing each coating solution in a sand mill for 6 hours, each coating solution was applied onto the casein undercoat layer using a Mayer bar to a dry film thickness of 0.1μ, and dried to form a charge generation layer. Ta. Then, the structural formula 5 g of hydrazone compound and 5 g of polymethyl methacrylate resin (number average molecular weight 100,000) were added to benzene.
The solution was dissolved in 70 ml and applied onto the charge generation layer using a Mayer bar so that the film thickness after drying was 12μ, and dried to form a charge transport layer. The 15 types of electrophotographic photoreceptors prepared in this way were tested using an electrostatic copying paper tester Model SP- manufactured by Kawaguchi Electric Co., Ltd.
428 using a static method with a corona charge of -5 KV, held in a dark place for 1 second, and then exposed to light for 4 seconds at an illuminance of 5 lux to examine charging characteristics. As for the charging characteristics, the initial charging potential (V ₀ ) and the amount of exposure (E1/2) required to attenuate the potential to 1/2 after dark decaying for 1 second were measured. The results are shown in Table 1. Also, the residual potential after 20lux, sec exposure
Expressed in _VR .

[Table] Example 16 Polyester resin (manufactured by Toyobo Co., Ltd., Byron
200) 5g and 1-[pyridyl-(2)]-3-(4-N,
N-diethylaminostyryl)-5-(4-N,N
After dissolving 5 g of (diethylaminophenyl) pyrazoline in 80 ml of methyl ethyl ketone, 1.0 g of the above-mentioned tropilum salt compound No. 9 was added and dispersed.
A photoreceptor having a photosensitive layer with a dry film thickness of 13 μm was prepared by coating and drying on a polyester film on which aluminum was vapor-deposited. The characteristics of this photoreceptor were determined by the same method as in Example 1, including the initial charging potential (V ₀ ) and the exposure amount (E
1/2) was measured, and the results were as follows.
(However, the charging polarity was set.) V ₀ : +580V E1/2 : 4.9lux.sec Example 17 1 g of poly-N-vinylcarbazole and 5 mg of the aforementioned tropylium salt compound No. 23 were added to 10 g of 1,2-dichloroethane. After that, the mixture was thoroughly stirred. The coating solution 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 μm. The charging characteristics of this photoreceptor were measured in the same manner as in Example 1. However, the charging polarity was determined.
The results are shown below. V ₀ : +560V E1/2 : 5.3lux.sec Example 18 The tropilium salt compound No. 24 was used instead of the tropilium salt compound No. 23 used when preparing the electron photoreceptor of Example 17. A photoreceptor was prepared in exactly the same manner as in Example 17, and then the charging characteristics of this photoreceptor were measured. The results are shown below. However, the charging polarity was taken into account. V ₀ : +570V E1/2: 4.6lux.sec Example 19 Particulate zinc oxide (Sazex2000 manufactured by Sakai Chemical Co., Ltd.) 10
g, 4 g of acrylic resin (Dyanal LR009 manufactured by Mitsubishi Rayon Co., Ltd.), 10 g of toluene, and 10 mg of the above-mentioned tropylium salt compound No. 21 were thoroughly mixed in a ball mill, and the resulting coating liquid was deposited with aluminum. It was applied onto a polyethylene terephthalate film using 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 long wavelength side compared to the zinc oxide coating that did not contain the tropylium salt compound. It turned out that it has. Example 20 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, a coating solution containing the same tropylium salt compound as in Example 8 was applied onto the previously formed polyvinyl alcohol layer using a Mayer bar so that the film thickness after drying was 0.1μ, dried and charged. A generation layer was formed. Then the structural formula A solution prepared by dissolving 5 g of pyrazoline compound and 5 g of polyarylate resin (condensation polymer of bisphenol A and terephthalic acid-isophthalic acid) in 70 ml of tetrahydrofuran was placed on the charge generation layer to determine the film thickness after drying.
It was applied to a thickness of 10μ 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. V ₀ :-590V E1/2 : 2.8lux.sec Example 21 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, 5 g of 2,4,7-trinitro-9-fluorenone and 5 g of poly-N-vinylcarbazole (number average molecular weight 300,000) were added to 70 ml of tetrahydrofuran.
to form a charge transfer complex. This charge transfer complex compound and the aforementioned tropylium salt compound No.
11 g was added to a solution in which 5 g of polyester resin (Vylon, manufactured by Toyobo) was dissolved in 7.0 ml of tetrahydrofuran, 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 prepared photoreceptor were measured in the same manner as in Example 1. These results were as follows. However, the charging polarity was determined. V ₀ : 560V E1/2: 4.5lux.sec

Claims (1)

[Claims] 1. A photoconductive coating containing a tropylium salt compound represented by the following general formula (). general formula m represents an integer selected from 0, 1, 2, and 3, and R ₁ to R ₆ are an alkyl group, an aralkyl group, an aryl group, or two adjacent groups selected from R ₁ to _{R 6}
one group represents a residue forming a fused ring with the tropylium ring, and X is or However, R ₇ and R ₈ represent an aromatic hydrocarbon group or a heterocyclic group which may have a substituent, n is an integer of 0 or 1, Y is -O-, -S-, -Se-, Te or N
-R ₁₅ represents a substituted or unsubstituted alkyl group, aralkyl group, or aryl group, and Z represents a 5- or 6-membered heterocycle that may have a substituent or a substituent _. 5 or 6 fused with an aromatic ring such as benzene, naphthalene, etc.
Residues for forming a member heterocycle are shown, R ₉ to _{R 14} are synonymous with R ₁ to R ₆ , and the general formula ()
Hydrogen attached to a carbon atom in the chain connecting X and the tropylium ring may be substituted with a functional group. A ^- represents an anionic group. 2. An electrophotographic photoreceptor comprising a conductive support and a photosensitive layer having a photoconductive film containing a tropylium salt compound represented by the following general formula (). general formula m represents an integer selected from 0, 1, 2, and 3, and R ₁ to R ₆ are an alkyl group, an aralkyl group, an aryl group, or two adjacent groups selected from R ₁ to _{R 6}
one group represents a residue forming a fused ring with the tropylium ring, and X is or However, R ₇ and R ₈ represent an aromatic hydrocarbon group or a heterocyclic group which may have a substituent, n is an integer of 0 or 1, Y is -O-, -S-, -Se-, Te or N
-R ₁₅ represents a substituted or unsubstituted alkyl group, aralkyl group, or aryl group, and Z represents a 5- or 6-membered heterocycle that may have a substituent or a substituent _. 5 or 6 fused with an aromatic ring such as benzene, naphthalene, etc.
Residues for forming a member heterocycle are shown, R ₉ to _{R 14} are synonymous with R ₁ to R ₆ , and the general formula ()
Hydrogen attached to a carbon atom in the chain connecting X and the tropylium ring may be substituted with a functional group. A ^- represents an anion group. 3. The photosensitive layer provided on the conductive support comprises at least a charge generation layer and a charge transport layer having a photoconductive coating containing a tropylium salt compound represented by the general formula () of claim 2. The electrophotographic photoreceptor according to claim 2, which is formed by sequentially laminating layers.