JP2549373B2 - Electrophotographic photoreceptor - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an electrophotographic photoreceptor, and more particularly to an electrophotographic photoreceptor provided with a eutectic complex layer containing a specific compound as a main component between a conductive substrate and a photosensitive layer. The present invention relates to a photosensitive member for electrophotography.

2. Description of the Related Art Recently, as a photoreceptor used in an electrophotographic copying machine, a photoreceptor using an organic photosensitive material, which has advantages of low cost, productivity and no pollution, has begun to be used.

For organic electrophotographic photoreceptors, photoconductive resin typified by polyvinylcarbazole (PVK), PVK-TNF (2,4,7
A charge transfer complex type typified by trinitrofluorenone), a pigment dispersion type typified by a phthalocyanine-binder, and a function separation type photoconductor in which a charge generation substance is used in combination are known. Photoconductors are receiving attention.

When such a function-separated type photoreceptor is applied to the Carlson process, the chargeability is low, the charge retention is poor (dark decay is large), and the deterioration of these characteristics due to repeated use is large. It has the drawbacks of density unevenness, fog, and background stain in the case of reversal development.

Generally, the chargeability of a high-sensitivity photoreceptor decreases due to pre-exposure fatigue. Since the pre-exposure fatigue is mainly caused by light absorbed by the charge generation material, the longer the charge generated by the light absorption remains in the photoconductor in a movable state, and the larger the number of the charge It is considered that the lower the chargeability due to the pre-exposure fatigue becomes, the more the more. That is, even if the charging operation is performed in a state where the charge generated by light absorption remains, the surface charge is neutralized by the movement of the remaining carrier, so that the surface potential increases until the residual charge is consumed. do not do. Therefore, the rise of the surface potential is delayed by the amount of pre-exposure fatigue, and the apparent charging potential becomes low.

For the above-mentioned disadvantages, for example, JP-A-47-6341, 48-35
44 and 48-12034, a cellulose nitrate resin intermediate layer is disclosed in JP-A-48-47344, 52-25638, 58-30757, 58-639.
45, 58-95351, 58-98739 and 60-66258 have nylon resin intermediate layers, and JP-A-48-26141 has vinyl acetate resin intermediate layers, and JP-A-49-69332 and 52-10138. And a maleic acid resin intermediate layer, and JP-A-58-105155.
Discloses polyvinyl alcohol resin intermediate layers.

Further, an intermediate layer has been proposed in which various conductive additives are contained in a resin in order to control the electric resistance of the intermediate layer. For example, JP-A-51-65942 discloses an intermediate layer in which a carbon or chalcogen-based substance is dispersed in a curable resin.
No. 82238 discloses a thermopolymer intermediate layer containing a quaternary ammonium salt and using an isocyanate-based curing agent.
JP-A-80451 discloses a resin intermediate layer to which a resistance modifier is added, JP-A-58-58556 discloses a resin intermediate layer in which an oxide of aluminum or tin is dispersed, and JP-A-58-93062 discloses an organometallic compound. Is added to the resin intermediate layer, JP-A-58-93063, 6
0-97363 and the resin intermediate layer formed by dispersing conductive particles No. 60-111255 is, the more JP 59-84257,59-93453 and No. 60-32054 by dispersing TiO ₂ and SnO ₂ powder A resin interlayer is disclosed.

Furthermore, a resin intermediate layer containing an electron-accepting organic compound as a substance having a negative charge transfer property has been proposed from the viewpoint of controlling charge transfer instead of electric resistance. For example, JP-A-53-89433 discloses an organic polymer photoconductor intermediate layer to which a polycyclic aromatic nitro compound is added, and JP-A-54-4134, 59-160147 and 59-170846.
JP-A No. 1994-242242 discloses a resin intermediate layer containing an electron-accepting organic substance.

However, the reduction in chargeability due to repeated use, particularly the delay in the rise of the charge potential, is still insufficient, and further improvement has been desired.

SUMMARY OF THE INVENTION An object of the present invention is to improve the chargeability of a photoreceptor, and more specifically, to provide a photoreceptor which does not delay the rise of a charged potential after repeated use.

Structure The present inventors provide an electrophotographic photoreceptor having a photosensitive layer provided on a conductive substrate, wherein a pyrylium-based dye, an electrically insulating polymer and the following general formula (I) are provided between the conductive substrate and the photosensitive layer. It has been found that by providing a eutectic complex layer containing a compound represented by the following formula as a main component, an electrophotographic photoreceptor having no delay in the rise of the charging potential after repeated use can be obtained.

(In the formula, R ₁ represents an alkyl group having 1 to 11 carbon atoms, a substituted or unsubstituted phenyl group or a heterocyclic group, R ₂ and R ₃ may be the same or different, hydrogen atom, carbon Represents an alkyl group of formulas 1 to 4, a hydroxyalkyl group, a chloroalkyl group, or a substituted or unsubstituted aralkyl group, and R ₂ and R ₃ may be bonded to each other to form a nitrogen-containing heterocycle; R ₄ and R ₅ may be the same or different and each represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group, or a halogen atom.) The present invention will be specifically described below with reference to the accompanying drawings.

FIGS. 1a and 1b are cross-sectional views showing a configuration example of an electrophotographic photoreceptor of the present invention, in which a eutectic complex layer 13 is provided on a conductive substrate 11, and a photosensitive layer 15 is further provided thereon. It is. The photosensitive layer 15 is a single layer, the charge generation layer 21 and the charge transport layer.
Some are made up of 22 layers.

FIG. 2 shows another configuration example of the present invention, in which an undercoat layer 12 is provided between a conductive substrate and a eutectic complex layer.

FIGS. 3A and 3B show another constitutional example of the present invention, in which a sealing layer 14 is provided between the eutectic complex layer and the photosensitive layer.

The conductive substrate 11 has conductivity with a volume resistance of 10 ¹⁰ Ωcm or less, for example, metals such as aluminum, nickel, chromium, nichrome, copper, silver, gold and platinum, and metal oxides such as zirconium oxide and indium oxide. Film- or cylinder-shaped plastic or paper coated by vapor deposition or sputtering, or aluminum, aluminum alloy, nickel, stainless steel, etc. plates and these are made into a raw tube by methods such as DI, II, extrusion, and drawing. rear,
Pipes and the like that have been surface-treated by cutting, superfinishing, polishing, or the like can be used.

The eutectic complex layer 13 is formed mainly of a eutectic complex and a conductive substance represented by the general formula (I). The eutectic complex here is formed from a pyrylium-based dye and an electrically insulating polymer.

There are three types of pyrylium dyes, a pyrylium salt, a thiapyrylium salt, and a selenapyrylium salt, which have the following general formula.

In the above formula, R ^a , R ^b , R ^c , R ^d, and R ^e are each (a) a hydrogen atom (b) an alkyl group, typically methyl, ethyl, propyl, isopropyl, butyl, t-butyl, amyl , C ₁ -C ₁₅ alkyl groups such as isoamyl, hexyl, octyl, nonyl, dodecyl (ha) methoxy, ethoxy, propoxy, butoxy,
Alkoxy groups such as amyloxy, hexoxy and octoxy (d) Alkylphenyls such as phenyl, 4-diphenyl, 4-ethylphenyl and 4-propylphenyl; 4
-Alkoxyphenyls such as ethoxyphenyl, 4-methoxyphenyl, 4-amyloxyphenyl, 2-hexoxyphenyl, 2-methoxyphenyl and 3,4-dimethoxyphenyl; 2-hydroxyethoxyphenyl, 3-hydroxyethoxyphenyl, etc. Β-hydroxyalkoxyphenyls; 4-hydroxyphenyl, 2,4-dichlorophenyl, 3,4-dibromophenyl, 4-chlorophenyl, halophenyls such as 3,4-dichlorophenyl;
Aminophenyls such as azidophenyl, nitrophenyl, 4-diethylaminophenyl and 4-dimethylaminophenyl; naphthyl, styryl, methoxystyryl, diethoxystyryl, dimethylaminostyryl, 1-butyl-4-p-dimethylaminophenyl-1. Represents an aryl group including a substituted aryl group such as vinyl-substituted aryl group such as 1,3-butaenyl, β-ethyl-4-dimethylaminostyryl, etc., X is a sulfur, oxygen or selenium atom, or Z ⁻ is a perk. It is an anionic functional group such as lorate, fluoroborate, iodide, chloride, bromide, sulfate, periodate, p-toluenesulfonate, and hexafluorophosphate.

Further, R ^a , R ^b , R ^c , R ^d and R ^e may be the atoms necessary to complete an aryl ring fused to the pyrylium nucleus.

 Representative examples of such pyrylium dyes are shown below.

Particularly useful pyrylium dyes are those having the general formula:

R ^a and R ^e in the formula is an aryl group such as a substituted phenyl group having at least one substituent selected from alkoxy groups of the alkyl group and C ₁ -C ₆ of C ₁ ~C _6, R ^c is The alkyl moiety may be a C ₁ -C ₆ alkylamino-substituted phenyl group, dialkylamino-substituted or haloalkylamino-substituted phenyl group. X is an oxygen or sulfur atom, and Z is as described above.

As the electrically insulating polymer, one having an alkylidene diarylene portion represented by the following formula in the main chain (repeating unit) is particularly useful.

In the formula, R ¹ ′ and R ² ′ are each a hydrogen atom, methyl containing a substituted alkyl group such as trifluoromethyl, ethyl, propyl, isopropyl, butyl, t-butyl, pentyl, hexyl, heptyl, octyl, nonyl, An aryl group such as phenyl and naphthyl, which includes an alkyl group such as decyl, a halogen, and a substituted aryl group having a substituent such as a C _{1 to} C ₅ alkyl group, and R ¹ ′ and R ² ′ are jointly defined. It may be a carbon atom necessary to form a cyclic hydrocarbon group including cycloalkanes such as cyclohexyl and polycycloalkanes such as norbornyl.
R ² ′ and R ⁴ ′ are hydrogen, a C _{1 to} C ₆ alkyl group or chloro,
Is a halogen such as bromine or iodine, and R ⁵ ′ is as well as It is a divalent group selected from the group consisting of:

Hydrophobic carbonate polymers (polycarbonate) composed of repeating units of the following formula are also useful and preferred.

In the formula, R is a phenylene group including halo-substituted phenylene groups and alkyl-substituted phenylene groups, and R ₄ and
R ₅ is as described above. These polymers are USP 3,028,365
No. 3,317,466. Preferably, a polymer containing an alkylidene diarylene moiety in the repeating unit, such as that made from bisphenol A, formed by transesterification between diphenyl carbonate and 2,2-bis (4-hydroxyphenyl) propane Polycarbonates are useful. Such polymers are described in USP Nos. 2,999,750, 3,038,874, 3,038,880,
No. 3,106,544, No. 3,106,545, No. 3,106,546 and the like. In any case, the film-forming polycarbonate resins can be widely used. Satisfactory results are obtained, especially with those having an intrinsic viscosity of about 0.5 to 1.8.

 Specific examples of the electrically insulating polymer are as follows.

In addition, typical examples of the compound represented by formula (I) are shown below.

In order to form the eutectic complex layer 13 of the present invention, the pyrylium-based dye, the electrically insulating polymer, and the compound represented by the general formula (I) are mixed with a suitable solvent such as tetrahydrofuran, toluene, 1,2- Dichloroethane, methylene chloride,
Dissolve in chloroform, monochlorobenzene, dichlorobenzene, benzene, etc., apply it on the conductive substrate 11 and dry at 50 to 130 ° C. to form a eutectic complex layer having a thickness of 0.05 to 30 μm, preferably 0.2 to 5 μm. May be formed.

The coating can be performed by using a dip coating method, a bead coating method, a spray coating method, a wire blade, a doctor blade, an air knife or the like.

During this coating and drying, a eutectic complex is formed with the pyrylium dye and the electrically insulating polymer.

The proportion of each component in the eutectic complex layer 13 is suitably 5 to 80 parts by weight of the electrically insulating polymer and 1 to 50 parts by weight of the compound represented by the general formula (I) based on 1 part by weight of the pyrylium-based dye. is there. The weight ratio of the electrically insulating polymer to the compound of the general formula (I) is appropriately 0.1 to 5 parts by weight of the compound of the general formula (I) to 1 part by weight of the electrically insulating polymer.

Further, when forming the layer 13, a leveling agent such as silicone oil may be added to the coating liquid. The amount used is appropriately about 0 to 1% by weight with respect to the electrically insulating polymer. Examples of the silicone oil used here include dimethyl silicone oil, methylphenyl silicone oil, methylchlorophenyl silicone oil, fluorosilicone oil, methyl hydrogen silicone oil, alkyl-modified silicone oil, higher fatty acid-modified silicone oil, and amino-modified silicone. There is oil etc.

Further, when providing the eutectic complex layer 13, a binder may be used if necessary.

As the binder material here, polyethylene, polystyrene, polybutadiene, styrene-bumediene copolymer, acrylate or methacrylate polymer and copolymer, polyester, polyamide, epoxy resin, urethane resin, silicone resin, Alkyd resins, cellulosic resins, poly-N-vinylcarbazole and derivatives thereof (for example, those having a carbazole skeleton having a halogen such as chlorine or bromine, a substituent such as a methyl group or an amino group), polyvinylpyrene, polyvinylanthracene, pyrene- Formaldehyde polymers and derivatives thereof (for example, those having a halogen such as bromine or a substituent such as a nitro group in the pyrene skeleton), poly-γ-carbazolylethyl-L-daltamate, styrene resin, chlorinated polyethylene, acetal Fat, such as melamine resins.

In the present invention, by providing the undercoat layer 12 between the conductive substrate and the eutectic complex layer as shown in FIG. 2, the chargeability and the adhesiveness can be improved.

For the undercoat layer 12, an inorganic material such as SiO or Al ₂ O ₃ is provided by a method such as evaporation, sputtering, or anodic oxidation, or a polyamide resin, an alcohol-soluble nylon resin, a water-soluble polyvinyl butyral resin, or a polyvinyl butyral resin. A resin layer such as a polyvinyl alcohol resin can be used.

In addition, the resin undercoat layer having pigment particles such as ZnO, TiO ₂ , and ZnS dispersed therein can also be used as the undercoat layer.

Further, as the undercoat layer 12 of the present invention, a silane coupling agent, a titanium coupling agent, a chromium coupling agent, or the like can be used.

 The thickness of the undercoat layer 12 is suitably from 0 to 5 μm.

Further, as shown in FIGS. 3a and 3b, a sealing layer 14 can be provided between the eutectic complex layer and the photosensitive layer. That is, when the photosensitive layer is coated on the eutectic complex layer, the eutectic complex layer may be dissolved or swollen depending on the solvent of the photosensitive layer coating solution, which may be an obstacle to layer formation. In this case, by providing the filling layer, a uniform photosensitive layer can be provided without dissolving and swelling the eutectic complex layer.

However, the solvent of the photosensitive layer coating solution dissolves the eutectic complex layer,
When not swelling, when the solvent is quick-drying, or when the amount of the solvent contained in the coating such as spray coating is small, it is not always necessary to provide the sealing layer.

As the filling layer 14, a resin layer such as a polyamide resin, an alcohol-soluble nylon resin, a water-soluble polyvinyl butyral resin, a polyvinyl butyral resin, and a polyvinyl alcohol resin can be used.

Next, the photosensitive layer 15 will be described. First, the laminated photosensitive layer will be described.

The charge generation layer 21 is a layer containing a charge generation substance as a main material,
A binder resin may be used if necessary.

As the binder resin, polyamide, polyurethane, polyester, epoxy resin, polyketone, polycarbonate, silicone resin, acrylic resin, polyvinyl butyral, polyvinyl formal, polyvinyl ketone, polystyrene, poly-N-vinylcarbazole, polyacrylamide and the like are used.

Examples of the charge generating substance include, for example, CI Pigment Blue 25 [Color Index (CI) 21180], CI Pigment Red 41 (CI 21200), CI Acid Red 52 (CI 45100), CI Basic Red 3
(CI 45210), a phthalocyanine pigment having a porphyrin skeleton, an azo pigment having a carbazole skeleton (described in JP-A-53-95033), and an azo pigment having a distyrylbenzene skeleton (JP-A-53-133455). ), An azo pigment having a triphenylamine skeleton (described in JP-A-53-132547), an azo pigment having a dibenzothiophene skeleton (described in JP-A-54-21728),
Azo pigments having an oxadiazole skeleton (JP-A-54-12)
742), azo pigments having a fluorenone skeleton (described in JP-A-54-22834), azo pigments having a bisstilbene skeleton (described in JP-A-54-17733), distyryl oxadi An azo pigment having an azole skeleton (described in JP-A-54-2129), an azo pigment having a distyrylcarbazole skeleton (described in JP-A-54-17734), and CIG Pigment Blue 16 (CI7
4100) and other phthalocyanine pigments, CIVAT BROWN 5 (CI 73410), CIVAT Die (CI 73030)
And indigo-based pigments such as Argos Scarlet B (manufactured by Violet) and Indense Scarlet R (manufactured by Bayer).

Among these charge generating substances, the azo pigment is particularly preferable. Further, among the azo pigments, a trisazo pigment represented by the following formula (II) or a disazo pigment represented by the following formula (III) is preferable.

(In the formula, A ¹ is Where X ₁ , Ar ¹ , Ar ² , R ¹ ″, R ² ″ are as follows.

X: aromatic ring such as benzene ring or naphthalene ring, or hetero ring such as indole ring, carbazole ring or benzofuran ring, or a substitution product thereof, Ar ¹ : aromatic ring such as benzene ring or naphthalene ring, or dibenzofuran ring Such as hetero ring or a substitution product thereof, Ar ² : aromatic ring such as benzene ring or naphthalene ring or a substitution product thereof, R ¹ ″: hydrogen, lower alkyl group or phenyl group or substitution product thereof, R ² ″: Lower alkyl, phenyl group, carboxyl group or ester thereof) (In the formula, A ² is Or Where X, Ar ¹ , Ar ² , Ar ³ , R ¹ ″, R ² ″, R ³ ″ are as follows.

X: aromatic ring such as benzene ring or naphthalene ring, or hetero ring such as indole ring, carbazole ring or benzofuran ring, or a substitution product thereof, Ar ¹ , Ar ³ : aromatic ring such as benzene ring or naphthalene ring, Or a hetero ring such as a dibenzolane ring or a substituted product thereof, Ar ² : an aromatic ring such as a benzene ring or a naphthalene ring or a substituted product thereof, R ¹ ″, R ³ ″: hydrogen, a lower alkyl group or a phenyl group or the Substitutes, R ² ″: lower alkyl group, phenyl group, carboxyl group or ester thereof) Specific examples of these trisazo pigments and disazo pigments are shown in Tables 1 and 2 below.

These charge generating substances may be used alone or in combination of two or more.

The binder resin is appropriately used in an amount of 0 to 100 parts by weight, preferably 0 to 5 parts by weight, based on 100 parts by weight of the charge generating substance.
0 parts by weight.

The charge generation layer may include a charge generation material together with a binder resin if necessary, tetrahydrofuran, cyclohexane,
It can be formed by dispersing with a ball mill, an attritor, a sand mill or the like using a solvent such as dioxane or dichloroethane, and appropriately diluting the dispersion. The coating can be performed by a dip coating method, a spray coating method, a bead coating method, or the like.

The thickness of the charge generation layer is suitably about 0.01 to 5 μm, and preferably 0.1 to 2 μm.

The charge transport layer 22 can be formed by dissolving or dispersing a charge transport substance and a binder resin in an appropriate solvent, applying the solution on the charge generating layer, and drying the solution. If necessary, a plasticizer or a leveling agent can be added.

The charge transport material includes a hole transport material and an electron transport material.

Examples of the hole-transporting substance include poly-N-vinylcarbazole and its derivative, poly-γ-carbazolylethylglutamate and its derivative, pyrene-formaldehyde condensate and its derivative, polyvinylpyrene, polyvinylphenanthrene, oxazole derivative, and oxadiene. Azole derivative, imidazole derivative, triphenylamine derivative, 9- (p-diethylaminostyryl) anthracene, 1,1-bis- (4-dibenzylaminophenyl) propane, styrylanthracene, styrylpyrazoline, phenylhydrazones, α- Examples thereof include electron-donating substances such as phenylstilbene derivatives.

Examples of the electron transport material include chloranil, bromanil, tetracyanoethylene, tetracyanoquinone dimethane, 2,4,7-trinitro-9-fluorenone,
2,4,5,7-Tetranitro-9-fluorenone, 2,4,5,7-
Tetranitroxanthone, 2,4,8-trinitrothioxanthone, 2,6,8-trinitro-4H-indeno [1,2-b]
Electron accepting substances such as thiophen-4-one and 1,3,7-trinitrodibenzothiophene-5,5-dioxide are exemplified.

These charge transport materials may be used alone or in combination of two or more.

As the binder resin, polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyethylene, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, polyvinyl chloride Vinylidene, polyarylate resin, phenoxy resin, polycarbonate, cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral, polyvinyl formal, polyvinyl toluene,
Examples thereof include thermoplastic or thermosetting resins such as poly-N-vinylcarbazole, acrylic resin, silicone resin, epoxy resin, melamine resin, urethane resin, phenol resin, and alkyd resin.

As the solvent, tetrahydrofuran, dioxane, toluene, monochlorobenzene, dichloroethane, methylene chloride or the like is used.

The thickness of the charge transport layer 22 is suitably about 5 to 50 μm.

Next, the case where the photosensitive layer 15 has a single-layer structure will be described. In this case as well, in most cases, a function-separated type of charge-generating substance and charge-transporting substance is used.

That is, the compounds shown above can be used as the charge generating substance and the charge transporting substance.

The single-layer photosensitive layer can be formed by dissolving or dispersing the charge-generating substance, the charge-transporting substance and the binder resin in a suitable solvent, coating and drying the solution. Further, if necessary, a plasticizer, a leveling agent, etc. can be added.

As the binder resin, the binder resins mentioned above in the charge transport layer 22 may be used as they are, and the charge generation layer 21 may be used.
You may mix and use the binder resin mentioned in above.

The single-layer photosensitive layer is formed by dispersing a charge generating material, a charge transport material, and a binder resin using a solvent such as tetrahydrofuran, dioxane, dichloroethane, or cyclohexanone with a disperser or the like, by immersion coating, spray coating, or bead coating. It can be formed by coating with a coat or the like.

 The film thickness of the single-layer photosensitive layer is preferably about 5 to 50 μm.

In the present invention, it is also possible to further provide an insulating layer and a protective layer on the photosensitive layer 15.

Next, the present invention will be described in more detail by way of examples, but the present invention is not limited to the following examples.

Example 1 A eutectic complex layer coating solution having the following composition was applied on a polyethylene terephthalate film on which aluminum was deposited by a doctor blade to form a eutectic complex layer having a dry film thickness of 1 µm.

4- (4-dimethylaminophenyl) -2,6-diphenylthiapyrylium perchlorate 1 part by weight Polycarbonate (Panlite k-1300 manufactured by Teijin Kasei Co., Ltd.) 10 parts by weight Compound No. 2 (I) Compound 9 parts by weight Methylene chloride 600 parts by weight A charge generation layer coating solution having the following composition was applied thereon by a spray coating method to form a charge generation layer having a dry film thickness of 0.2 μm.

Pigment No. 1-18 Trisazo pigment 3 parts by weight Polyvinyl butyral (Sekisui Chemical Co., Ltd. S-REC BL-1) 1 part by weight Cyclohexanone 300 parts by weight Next, a coating solution having the following composition was applied onto this charge generation layer. Application was carried out by a spray coating method to form a charge transport layer having a dry film thickness of 18 μm to obtain an electrophotographic photoreceptor of the present invention.

90 parts by weight of a charge transport material of the following structural formula Polycarbonate (manufactured by Teijin Kasei Co., Ltd., Panlite k-1300) 100 parts by weight Tetrahydrofuran 800 parts by weight Example 2 In Example 1, the compound of formula (I) No. 2 used in the eutectic complex layer coating solution was used. An electrophotographic photosensitive member was prepared in the same manner as in Example 1 except that the compound of formula (I) No. 16 was used instead of.

Comparative Example 1 An electrophotographic photosensitive member was prepared in the same manner as in Example 1, except that no eutectic complex layer was provided.

Example 3 A coating solution having the following composition was applied on the same support as used in Example 1 with a doctor blade to form an undercoat layer having a dry film thickness of 0.1 μm.

Water-soluble polyvinyl butyral 25% aqueous solution (Sekisui Chemical Co., Ltd. S-REC W201) 50 parts by weight Water 150 parts by weight Methanol 200 parts by weight A coating solution having the following composition is applied thereon by a spray coating method to give a dry film thickness of 0.5. A μm eutectic complex layer was formed.

4- (4-Dimethylaminophenyl) -2,6-diphenylthiapyrylium hexafluorophosphate 1 part by weight Polycarbonate (GE's Lexan-141) 15 parts by weight Compound No. 25 (I) Formula 12 parts by weight Parts methylene chloride 450 parts by weight 1,2-dichloroethane 150 parts by weight Next, a coating solution having the following composition was applied thereon by a spray coating method to form a charge generation layer having a dry film thickness of 0.2 μm.

Pigment No. 2-20 Disazo pigment 3 parts by weight Polyvinyl butyral (Sekisui Chemical Co., Ltd. S-REC BM-S) 0.5 parts by weight Tetrahydrofuran 300 parts by weight Furthermore, a coating solution having the following composition is further spray-coated thereon. After coating, a charge transport layer having a dry film thickness of 18 μm was formed to obtain an electrophotographic photoreceptor of the present invention.

80 parts by weight of charge transport material having the following structural formula Polycarbonate (Panlite K-1300, Teijin Kasei Co., Ltd.) 100 parts by weight Tetrahydrofuran 800 parts by weight Example 4 In Example 3, instead of the compound of formula (I) No. 25 used for the eutectic complex layer coating solution. An electrophotographic photosensitive member was prepared in the same manner as in Example 3, except that the compound of formula (I) of No. 27 was used.

Comparative Example 2 An electrophotographic photosensitive member was prepared in the same manner as in Example 3, except that the eutectic complex layer was not provided.

Example 5 On a 0.2 mm thick aluminum plate, a coating solution having the following composition was applied by a dip coating method to form a eutectic complex layer having a dry film thickness of 2 μm.

4- (4-dimethylaminophenyl) -2,6-diphenylthiapyrylium fluoroborate 0.5 part by weight Polycarbonate (Panlite L-1250, Teijin Chemicals Ltd.) 7 parts by weight Compound No. 35 (I) 7 parts by weight Methylene chloride 600 parts by weight Carbon tetrachloride 200 parts by weight A coating solution having the following composition was applied thereon by a dip coating method to form a sealing layer having a dry film thickness of 0.3 μm.

Alcohol-soluble nylon (Torayzin manufactured by Teikoku Kagaku Co., Ltd.) 3 parts by weight Methanol 200 parts by weight Isopropyl alcohol 100 parts by weight Next, a coating solution having the following composition is applied onto this by a dip coating method to give a dry film thickness of 0.3 μm. A charge generation layer was formed.

Trisazo pigment of pigment No. 1-20 3 parts by weight Cyclohexanone 200 parts by weight Tetrahydrofuran 100 parts by weight Further, a coating solution having the following composition is applied by dip coating to form a charge transport layer having a dry film thickness of 20 μm. Thus, an electrophotographic photosensitive member of the present invention was obtained.

90 parts by weight of a charge transport material of the following structural formula Polycarbonate (Panlite C-1400 manufactured by Teijin Chemicals Ltd.) 100 parts by weight Methylene chloride 800 parts by weight Example 6 In Example 5, No. 35 used for the eutectic complex layer coating solution.
An electrophotographic photoreceptor was prepared in the same manner as in Example 5, except that the compound of formula (I) No. 48 was used instead of the compound of formula (I).

Comparative Example 3 An electrophotographic photosensitive member was prepared in the same manner as in Example 5 except that no eutectic complex layer was provided.

Example 7 An undercoat layer coating solution, a eutectic complex layer coating solution, and a filling layer coating solution having the following compositions were sequentially applied on an aluminum plate having a thickness of 0.2 mm.
Apply by dip coating method, dry and undercoat layer (film layer 0.2μm),
Eutectic complex layer (film thickness 0.7μm) and sealing layer (film layer 0.2μ)
m) were formed in sequence.

(1) Subbing layer coating liquid polyvinyl alcohol (Denka Poval H-20 manufactured by Denki Kagaku Kogyo KK) 2 parts by weight Water 200 parts by weight Methanol 100 parts by weight (2) Eutectic complex layer coating liquid 4- (4 -Dimethylaminophenyl) -2,6-diphenylpyrylium hexafluorophosphate 1 part by weight Polycarbonate (GE-made Lexan-141) 8 parts by weight Compound No. 55 (I) compound 10 parts by weight Methylene chloride 650 parts by weight (3) Sealing layer coating liquid Alcohol-soluble nylon (Amylan CM-8000 manufactured by Toray Industries, Inc.) 2 parts by weight Ethanol 250 parts by weight Next, a coating liquid having the following composition is applied onto this by a dip coating method, A charge generation layer having a dry film thickness of 0.3 μm was formed.

Pigment No. 2-7 disazo pigment 3 parts by weight Polyvinyl butyral (Sekisui Chemical Co., Ltd. S-REC BM-S) 0.5 parts by weight Cyclohexanone 200 parts by weight Tetrahydrofuran 100 parts by weight Further, a coating solution having the following composition is dipped in the solution. Coating was carried out by a coating method to form a charge transport layer having a dry film thickness of 20 μm to obtain an electrophotographic photoreceptor of the present invention.

90 parts by weight of a charge transport material of the following structural formula Polycarbonate (Panlite C-1400 manufactured by Teijin Chemicals Ltd.) 100 parts by weight Methylene chloride 800 parts by weight Example 8 In Example 7, No. 55 used for the eutectic complex layer coating solution.
An electrophotographic photosensitive member was prepared in the same manner as in Example 7, except that the compound of the formula (I) of No. 69 was used instead of the compound of the formula (I).

Comparative Example 4 An electrophotographic photosensitive member was prepared in the same manner as in Example 7, except that no eutectic complex layer was provided.

The electrophotographic photoreceptor prepared as described above was evaluated for electrophotographic characteristics in the following manner using an electrostatic copying paper tester (SP-428 manufactured by Kawaguchi Denki Seisakusho).

First, corona charging was performed for 15 seconds at a discharge voltage of −5,5 kV, then dark decay was performed, and when the surface potential became −800 V, 10 lux tungsten light was irradiated.

At this time, the surface potential V ₂ (V) for 2 seconds after the start of charging, and the exposure amount E _1/2 required for the surface potential to become −400 V during light irradiation.
(Lux sec) was measured.

Furthermore, the photoreceptor in the tungsten light of color temperature 2856 ° k and 100,000Lux sec irradiation After light fatigue, in the same manner as again the charge potential V ₂ '(V), the exposure amount E' _1/2 (Lux
The following table shows the evaluation results measured in this way.

Effects According to the present invention, it becomes possible to prevent the deterioration of the charging characteristics after the repeated use of the photoconductor.

That is, in image density reduction, image density unevenness, fog or reversal development of a copying machine, a printer, etc.,
A good image without background stain can be obtained.

[Brief description of drawings]

FIGS. 1a and 1b, 2 and 3a and 3b are cross-sectional views showing respective structural examples of the electrophotographic photosensitive member of the present invention. 11 ... conductive substrate, 15 ... photosensitive layer 12 ... undercoat layer, 21 ... charge generation layer 13 ... eutectic complex layer, 22 ... charge transport layer 14 ... filler layer

 ─────────────────────────────────────────────────── --- Continuation of the front page (72) Inventor Satoshi Taniguchi 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd. (72) Kayoko Yokoyama 1-3-6 Nakamagome, Ota-ku, Tokyo (56) References JP 54-24027 (JP, A) JP 55-32078 (JP, A) JP 56-39549 (JP, A) JP 56-121044 ( JP, A) JP-B-46-22518 (JP, B1)

Claims (1)

(57) [Claims] 1. An electrophotographic photosensitive member comprising a photosensitive layer provided on a conductive substrate, wherein an electrophotographic photosensitive member is provided between the conductive substrate and the photosensitive layer.
A pyrylium-based dye, an electrically insulating polymer and the following general formula (I): (In the formula, R ₁ represents an alkyl group having 1 to 11 carbon atoms, a substituted or unsubstituted phenyl group or a heterocyclic group, R ₂ and R ₃ may be the same or different, hydrogen atom, carbon Represents an alkyl group, a hydroxyalkyl group, a chloroalkyl group, or a substituted or unsubstituted aralkyl group of the formulas _{1 to 4,} and R ₂ and R ₃ may combine with each other to form a nitrogen-containing heterocycle; R ₄ and R ₅ may be the same or different and each represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group, or a halogen atom). An electrophotographic photoconductor, which is provided.