WO2015114819A1

WO2015114819A1 - Electrophotographic photoreceptor and method for manufacturing same

Info

Publication number: WO2015114819A1
Application number: PCT/JP2014/052340
Authority: WO
Inventors: 豊強朱; 鈴木　信二郎; 友士中村
Original assignee: 富士電機株式会社
Priority date: 2014-01-31
Filing date: 2014-01-31
Publication date: 2015-08-06

Abstract

The purpose of the present invention is to provide an electrophotographic photoreceptor having high sensitivity, low residual potential, and no optical fatigue, and a method for manufacturing the electrophotographic photoreceptor. Disclosed is an electrophotographic photoreceptor wherein one or more functional layers including a photosensitive layer (3) are provided on a conductive base body (1), and at least one layer of the functional layers contains a red dye compound. Also disclosed is an electrophotographic photoreceptor manufacturing method, which includes a step for forming at least the one layer of the one or more functional layers including the photosensitive layer by applying a coating liquid to the conductive base body, said coating liquid containing the red dye compound.

Description

Electrophotographic photoreceptor and method for producing the same

The present invention relates to an electrophotographic photosensitive member (hereinafter also simply referred to as “photosensitive member”) used in electrophotographic printers, copying machines, facsimiles, and the like, and in particular, by adding a red dye. The present invention relates to an electrophotographic photoreceptor having high sensitivity, a low residual potential, and no light fatigue, and a method for producing the same.

An electrophotographic photoreceptor is required to have a function of holding a surface charge in a dark place, a function of receiving light to generate a charge, and a function of receiving light and transporting a charge. In addition, a so-called single-layer type photoconductor that combines these functions and a layer that separates the functions into a layer that mainly contributes to charge generation and a layer that contributes to the retention of surface charge in the dark and the charge transport during photoreception. In other words, there is a so-called multilayer photoconductor.

For example, the Carlson method is applied to image formation by electrophotography using these electrophotographic photoreceptors. In this method, the image is formed by charging the photoconductor in the dark, forming an electrostatic image such as text or a picture on the charged photoconductor surface, and developing the formed electrostatic image with toner. And the developed toner image is transferred and fixed onto a support such as paper. After the toner image has been transferred, the photoreceptor is subjected to reuse after removing residual toner or removing static electricity.

Examples of the material for the electrophotographic photoreceptor described above include those in which an inorganic photoconductive material such as selenium, selenium alloy, zinc oxide or cadmium sulfide is dispersed in a resin binder, poly-N-vinylcarbazole, 9 , 10-anthracenediol polyester, pyrazoline, hydrazone, stilbene, butadiene, benzidine, phthalocyanine, bisazo compound or other organic photoconductive material dispersed in a resin binder, or vacuum deposited or sublimated Is being used.

In recent years, electrophotographic photoconductors using organic materials have been put into practical use due to advantages such as flexibility, thermal stability, and film formability. For example, a photoreceptor composed of poly-N-vinylcarbazole and 2,4,7-trinitrolen-9-one (described in Patent Document 1), a photoreceptor mainly composed of an organic pigment (described in Patent Document 2). ), And a photoreceptor (described in Patent Document 3) having a eutectic complex composed of a dye and a resin as a main component.

Recently, a function-separated laminated type photoconductor in which a photosensitive layer is a laminate of a charge generation layer containing a charge generation material and a charge transport layer containing a charge transport material has become mainstream. In particular, a negatively charged type in which an organic pigment is used as a charge generation material, a vapor-deposited layer or a layer dispersed in a resin is used as a charge generation layer, and a charge transport layer is laminated thereon using an organic low-molecular compound as a charge transport material. Many organic photoreceptors have been proposed.

Although organic materials have many advantages that inorganic materials do not have, there are currently no materials that sufficiently satisfy all the characteristics required for electrophotographic photoreceptors. That is, image quality is deteriorated due to a decrease in charging potential, a residual potential increase, a sensitivity change, and the like due to repeated use. The cause of this deterioration has not been fully clarified, but as one of the factors, charge transport is caused by repeated exposure to image exposure and static elimination lamp light, and exposure to external light during maintenance. It is conceivable that the material etc. decomposes.

In order to suppress such deterioration due to light, proposals have been made to add dyes or ultraviolet absorbers to the surface protective layer or photosensitive layer of the photoreceptor. For example, Patent Document 4 describes that a dye having a light absorption characteristic including an absorption wavelength region of the charge transport layer or an ultraviolet absorber is added to the surface protective layer. Patent Document 5 describes that a yellow dye is added to the charge transport layer.

US Pat. No. 3,484,237 JP 47-37543 A JP 47-10785 A JP 58-160957 A JP 58-163946 A

However, there is still a problem that a sufficient effect is not yet obtained by the above-mentioned conventional technology, and that the addition of the above-described dye or ultraviolet absorber causes a decrease in sensitivity or an increase in residual potential. there were.

Accordingly, an object of the present invention is to provide an electrophotographic photoreceptor having high sensitivity, a low residual potential and no light fatigue, and a method for producing the same in order to solve the above-mentioned problems.

As a result of intensive studies to solve the above-mentioned problems, the present inventors have determined that a specific dye compound that has not been used in a photoreceptor until now is used as an undercoat layer, a photosensitive layer or a surface protective layer constituting the photoreceptor. The inventors have found that the above-mentioned object can be achieved by adding to the present invention, and have completed the present invention.

That is, the electrophotographic photoreceptor of the present invention is an electrophotographic photoreceptor comprising one or more functional layers including a photosensitive layer on a conductive substrate, wherein at least one of the functional layers is a red dye. It is characterized by containing a compound.

In the present invention, the photosensitive layer may contain the red dye compound. In this case, the photosensitive layer may include a charge generation layer, and the charge generation layer may include the red dye compound, the photosensitive layer includes a charge transport layer, and the charge transport layer includes the charge transport layer. The photosensitive layer may contain a red dye compound, and the photosensitive layer may be a single positively charged photosensitive layer. Further, in the present invention, the functional layer includes an undercoat layer, and the undercoat layer may contain the red dye compound, the functional layer includes a surface protective layer, and The surface protective layer may contain the red dye compound.

In the present invention, as the red dye compound, at least one selected from a compound containing a hydroxynaphthylazo group and a compound having a xanthene or xanthine skeleton can be preferably used. Specifically, examples of the red dye compound include 1- [4- (phenylazo) phenylazo] -2-naphthol, 1- (2,4-dimethylphenylazo) -2-naphthol, eosin blue ishes, rose bengal, Sudan IV, Bonso 3R, Bonso 4R, Bonso SX, Xylene Red, Naphthol Red, Acid Red 26, Erythrosin B, Phloxine B, Eosin, Rosselin, Rhodamine B Acetate, Rhodamine B Stearate, Tetrabromofluorescein, and Tetrachlorofluorescein It is preferable to use at least one selected from the group consisting of Furthermore, in this invention, the addition amount of the said red dye compound is suitably 3 mass parts or less with respect to 100 mass parts of resin binders of the layer used.

The method for producing an electrophotographic photoreceptor of the present invention includes a step of applying at least one coating layer on a conductive substrate to form at least one of one or more functional layers including a photosensitive layer. In the method for producing an electrophotographic photoreceptor, a red dye compound is contained in the coating solution.

According to the present invention, it is possible to realize an electrophotographic photoreceptor having high sensitivity, low residual potential and no light fatigue, and a manufacturing method thereof.

FIG. 2 is a schematic cross-sectional view of (a) a negatively charged function-separated laminated electrophotographic photoreceptor and (b) a positively charged single layer type electrophotographic photoreceptor of the present invention.

Hereinafter, specific examples of the electrophotographic photoreceptor according to the present invention will be described in detail with reference to the drawings. The present invention is not limited to the examples described below.

Electrophotographic photoreceptors are broadly classified into negatively charged laminated photoreceptors and positively charged laminated photoreceptors as function-separated laminated photoreceptors, and mainly positively charged single-layer photoreceptors. FIG. 1 is a schematic cross-sectional view showing an electrophotographic photoreceptor according to an embodiment of the present invention, in which (a) is a negatively charged laminated electrophotographic photoreceptor, and (b) is a positively charged type. Single-layer electrophotographic photoreceptors are shown respectively. As shown in the figure, in the negatively charged laminated type photoreceptor, a photosensitive layer comprising an undercoat layer 2, a charge generation layer 4 having a charge generation function, and a charge transport layer 5 having a charge transport function on a conductive substrate 1. Layer 3 is sequentially laminated. On the other hand, in a positively charged single layer type photoreceptor, an undercoat layer 2 and a single layer type photosensitive layer 3 having both functions of charge generation and charge transport are sequentially laminated on a conductive substrate 1. In any type of photoreceptor, the undercoat layer 2 may be provided as necessary, and a surface protective layer 6 may be further provided on the photosensitive layer 3.

The photoreceptor of the present invention is characterized in that the functional layer laminated on the conductive substrate contains a red dye compound. The photoreceptor of the present invention may have any of the above laminated structures. In the present invention, as a functional layer laminated on the conductive substrate 1, an undercoat layer 2, a charge generation layer 4, a charge transport layer. 5, single-layer type photosensitive layer 3, and surface protective layer 6. In the photoconductor of the present invention, the functional layer provided on the conductive substrate contains a red dye compound, thereby suppressing light fatigue without causing problems such as a decrease in sensitivity and an increase in residual potential. It became possible to do. This is considered to be due to the following reasons. That is, blue light or ultraviolet light has strong chemical activity and easily decomposes a functional material such as a charge transport material. However, when the red dye compound is contained in the functional layer of the photoreceptor, the red dye compound is converted into blue light or ultraviolet light. Since ultraviolet light is absorbed or blocked, it is possible to suppress decomposition of the functional material contained in the functional layer.

As such a red dye compound, for example, a compound containing a hydroxynaphthylazo group or a compound having a xanthene or xanthine skeleton can be preferably used. These compounds have an effect of mainly absorbing or blocking light having a wavelength of 380 nm to 495 nm by including a hydroxynaphthylazo group or a xanthene or xanthine skeleton. As such a compound, for example, one of the following compounds can be used alone, or two or more can be used in appropriate combination.

1- [4- (Phenylazo) phenylazo] -2-naphthol

1- (2,4-Dimethylphenylazo) -2-naphthol

Eosin blueish

Rose Bengal

Sudan IV

Bonso 3R

Bonso 4R
Bonso SX

Xylene red

Naphthol red

Acid Red 26

Erythrosin B

Phloxine B

Eosin

Rossellin

Rhodamine B acetate

Rhodamine B stearate

Tetrabromofluorescein

Tetrachlorofluorescein

In the present invention, the addition amount of the red dye compound is preferably 3 parts by mass or less, more preferably in the range of 0.10 to 1.0 part by mass with respect to 100 parts by mass of the resin binder of the layer to be used. It is. When the addition amount of the red dye compound exceeds 3 parts by mass, the sensitivity of the photoreceptor is lowered and there is a possibility that the residual potential is increased.

In the photoreceptor of the present invention, the desired effect of the present invention can be obtained as long as at least one of the one or more functional layers including the photosensitive layer contains the red dye compound. The red dye compound may be contained in two or more functional layers. In the present invention, the layer structure of the photoconductor is not particularly limited, and the photoconductor having any layer structure may be used.

The conductive substrate 1 serves as one electrode of the photoconductor, and also serves as a support for each layer constituting the photoconductor, and may be any shape such as a cylindrical shape, a plate shape, or a film shape. May be a metal such as aluminum, stainless steel, nickel or the like, or a surface of glass, resin or the like subjected to a conductive treatment.

The undercoat layer 2 is composed of a resin-based layer or a metal oxide film such as alumite, and controls the charge injection property from the conductive substrate to the photosensitive layer, or covers defects on the substrate surface, It is provided as necessary for the purpose of improving the adhesion between the layer and the substrate. Examples of the resin material used for the undercoat layer include insulating polymers such as casein, polyvinyl alcohol, polyamide, melamine, and cellulose, and conductive polymers such as polythiophene, polypyrrole, and polyaniline. These resins are used alone, Alternatively, they can be combined and used as appropriate. These resins can also contain metal oxides such as titanium dioxide and zinc oxide.

(Negatively charged laminated photoconductor)
As described above, the negatively charged laminated photoreceptor includes the photosensitive layer 3 formed by laminating the charge generation layer 4 and the charge transport layer 5.

As described above, the charge generation layer 4 is formed by a method such as applying a coating solution in which particles of a charge generation material are dispersed in a resin binder, and receives light to generate charges. In addition, the injection efficiency of the generated charges into the charge transport layer 4 is important at the same time as the charge generation efficiency is high, and it is desirable that the injection is good even in a low electric field with little electric field dependency. Examples of charge generation materials include phthalocyanines such as X-type metal-free phthalocyanine, τ-type metal-free phthalocyanine, α-type titanyl phthalocyanine, β-type titanyl phthalocyanine, Y-type titanyl phthalocyanine, γ-type titanyl phthalocyanine, amorphous-type titanyl phthalocyanine, and ε-type copper phthalocyanine. Compounds, various azo pigments, anthanthrone pigments, thiapyrylium pigments, perylene pigments, perinone pigments, squarylium pigments, quinacridone pigments, etc. can be used alone or in appropriate combination, and the light wavelength of the exposure light source used for image formation A suitable material can be selected according to the region. The content of the charge generation material in the charge generation layer 4 is preferably 20 to 80% by mass, more preferably 30 to 70% by mass with respect to the solid content in the charge generation layer 4.

Since the charge generation layer 4 only needs to have a charge generation function, the film thickness thereof is determined by the light absorption coefficient of the charge generation material, and is generally 1 μm or less, and preferably 0.5 μm or less. The charge generation layer can also be used with a charge generation material as a main component and a charge transport material or the like added thereto. Examples of the resin binder include polycarbonate resin, polyester resin, polyamide resin, polyurethane resin, vinyl chloride resin, vinyl acetate resin, phenoxy resin, polyvinyl acetal resin, polyvinyl butyral resin, polystyrene resin, polysulfone resin, diallyl phthalate resin, methacrylate ester. Resin polymers and copolymers can be used in appropriate combinations.

The charge transport layer 5 is mainly composed of a charge transport material and a resin binder. As the charge transport material, various hydrazone compounds, styryl compounds, diamine compounds, butadiene compounds, indole compounds, and the like can be used alone or in combination as appropriate. Further, as the resin binder, polycarbonate resins such as bisphenol A type, bisphenol Z type, bisphenol A type-biphenyl copolymer, polystyrene resins, polyphenylene resins, and the like can be used alone or in combination as appropriate. The charge transport material is used in an amount of 2 to 50 parts by weight, preferably 3 to 30 parts by weight, based on 100 parts by weight of the resin binder. The thickness of the charge transport layer is preferably in the range of 3 to 50 μm, more preferably 15 to 40 μm, in order to maintain a practically effective surface potential.

Specific examples of the charge transport material used in the present invention are shown below, but are not limited thereto.

(Positively charged single layer type photoreceptor)
In the positively charged single layer type photoreceptor, the single layer type photosensitive layer 3 is mainly composed of a charge generation material, a hole transport material, an electron transport material (acceptor compound), and a resin binder.

As the resin binder of the single-layer type photosensitive layer 3, other various polycarbonate resins such as bisphenol A type, bisphenol Z type, bisphenol A type-biphenyl copolymer, bisphenol Z type-biphenyl copolymer, polyphenylene resin, polyester resin , Polyvinyl acetal resin, polyvinyl butyral resin, polyvinyl alcohol resin, vinyl chloride resin, vinyl acetate resin, polyethylene resin, polypropylene resin, acrylic resin, polyurethane resin, epoxy resin, melamine resin, silicone resin, polyamide resin, polystyrene resin, polyacetal resin Other polyarylate resins, polysulfone resins, methacrylic acid ester polymers, copolymers thereof, and the like can be used. Furthermore, the same kind of resins having different molecular weights may be mixed and used. The content of the resin binder is preferably 10 to 90% by mass and more preferably 20 to 80% by mass with respect to the solid content of the single-layer type photosensitive layer 3.

As the charge generation material of the single-layer type photosensitive layer 3, for example, a phthalocyanine pigment, an azo pigment, an anthrone pigment, a perylene pigment, a perinone pigment, a polycyclic quinone pigment, a squarylium pigment, a thiapyrylium pigment, a quinacridone pigment, etc. Can do. These charge generation materials can be used alone or in combination of two or more. In particular, in the photoreceptor of the present invention, the azo pigment is a disazo pigment, a trisazo pigment, and the perylene pigment is N, N′-bis (3,5-dimethylphenyl) -3,4: 9,10-perylene. As the bis (carboximide) and phthalocyanine pigments, it is preferable to use metal-free phthalocyanine, copper phthalocyanine, and titanyl phthalocyanine. Also, X-type metal-free phthalocyanine, τ-type metal-free phthalocyanine, ε-type copper phthalocyanine, α-type titanyl phthalocyanine, β-type titanyl phthalocyanine, Y-type titanyl phthalocyanine, amorphous-type titanyl phthalocyanine, Japanese Patent Application Laid-Open No. 8-209003, US Pat. When titanyl phthalocyanine having a maximum Bragg angle 2θ of 9.6 ° in the CuKα: X-ray diffraction spectrum described in US Pat. No. 5,736,282 and US Pat. No. 5,874,570 is used, sensitivity, durability and image quality are improved. This is preferable because it shows a significantly improved effect. The content of the charge generating material is preferably 0.1 to 20% by mass, and more preferably 0.5 to 10% by mass with respect to the solid content of the single-layer type photosensitive layer 3.

Examples of the hole transport material of the single-layer type photosensitive layer 3 include hydrazone compounds, pyrazoline compounds, pyrazolone compounds, oxadiazole compounds, oxazole compounds, arylamine compounds, benzidine compounds, stilbene compounds, styryl compounds, poly-N— Vinyl carbazole, polysilane, etc. can be used. These hole transport materials can be used alone or in combination of two or more. As the hole transport material used in the present invention, a material that is excellent in the ability to transport holes generated during light irradiation and that is suitable in combination with a charge generation material is preferable. The content of the hole transport material is preferably 3 to 80% by mass, and more preferably 5 to 60% by mass with respect to the solid content of the single-layer type photosensitive layer 3.

As the electron transport material (acceptor compound) of the single-layer type photosensitive layer 3, succinic anhydride, maleic anhydride, dibromosuccinic anhydride, phthalic anhydride, 3-nitrophthalic anhydride, 4-nitrophthalic anhydride, anhydrous Pyromellitic acid, pyromellitic acid, trimellitic acid, trimellitic anhydride, phthalimide, 4-nitrophthalimide, tetracyanoethylene, tetracyanoquinodimethane, chloranil, bromanyl, o-nitrobenzoic acid, malononitrile, trinitrofluorenone, Trinitrothioxanthone, dinitrobenzene, dinitroanthracene, dinitroacridine, nitroanthraquinone, dinitroanthraquinone, thiopyran compounds, quinone compounds, benzoquinone compounds, diphenoquinone compounds, naphthoquinone compounds, anthraquinone compounds Compounds, stilbene quinone compounds, mention may be made of Azokinon based compound. These electron transport materials can be used alone or in combination of two or more. The content of the electron transport material is preferably 1 to 50% by mass, more preferably 5 to 40% by mass with respect to the solid content of the single-layer type photosensitive layer 3.

The film thickness of the single-layer type photosensitive layer 3 is preferably in the range of 3 to 100 μm and more preferably in the range of 5 to 40 μm in order to maintain a practically effective surface potential.

In the photoreceptor of the present invention, the undercoat layer 2, the charge generation layer 4, the charge transport layer 5 and the single-layer type photosensitive layer 3 have improved sensitivity, reduced residual potential, or environmental resistance and stability against harmful light Various additives may be included as necessary for the purpose of improving the durability and improving the high durability including the friction resistance. Examples of additives include succinic anhydride, maleic anhydride, dibromosuccinic anhydride, pyromellitic anhydride, pyromellitic acid, trimellitic acid, trimellitic anhydride, phthalimide, 4-nitrophthalimide, tetracyanoethylene, tetra Compounds such as cyanoquinodimethane, chloranil, bromanyl, o-nitrobenzoic acid and trinitrofluorenone can be used. Further, an antioxidant or a light stabilizer can be added to these layers. Compounds used for this purpose include chromanol derivatives such as tocopherol and ether compounds, ester compounds, polyarylalkane compounds, hydroquinone derivatives, diether compounds, benzophenone derivatives, benzotriazole derivatives, thioether compounds, phenylenediamine derivatives, phosphonic acids Examples include, but are not limited to, esters, phosphites, phenol compounds, hindered phenol compounds, linear amine compounds, cyclic amine compounds, hindered amine compounds, and the like.

Further, the photosensitive layer 3 may contain a leveling agent such as silicone oil or fluorine-based oil for the purpose of improving the leveling property of the formed film and imparting further lubricity.

A surface protective layer 6 may be further provided on the photosensitive layer surface as necessary for the purpose of further improving the environmental resistance and mechanical strength. It is desirable that the surface protective layer 6 is made of a material having excellent durability against mechanical stress and environmental resistance and has a performance of transmitting light sensitive to the charge generation layer with as low loss as possible.

The surface protective layer 6 is composed of a layer mainly composed of a resin binder or an inorganic thin film such as amorphous carbon. In resin binders, silicon oxide (silica), titanium oxide, zinc oxide, calcium oxide, aluminum oxide (alumina), oxidation are used for the purpose of improving conductivity, reducing friction coefficient, and imparting lubricity. Metal oxides such as zirconium, metal sulfates such as barium sulfate and calcium sulfate, metal nitrides such as silicon nitride and aluminum nitride, fine particles of metal oxide, or fluorine-based resins such as tetrafluoroethylene resin, fluorine-based Particles such as a comb-type graft polymerization resin may be included.

Further, for the purpose of imparting charge transportability, the surface protective layer 6 contains a charge transport material, an electron accepting material or the like used in the photosensitive layer, or improves the leveling property of the formed film and imparts lubricity. For the purpose, a leveling agent such as silicone oil or fluorine oil can be contained.

The film thickness of the surface protective layer 6 itself depends on the composition of the surface protective layer 6 itself, but can be arbitrarily set within a range where no adverse effect such as an increase in residual potential occurs when repeatedly used.

The photoreceptor of the present invention can obtain the above-described effects by being applied to various machine processes. Specifically, the photoreceptor of the present invention includes a charging process such as a contact charging method using a roller or a brush, a non-contact charging method using a corotron, a scorotron, or the like, and a nonmagnetic one component or a magnetic one component. The present invention is applied to various machines equipped with a development process using a two-component development system, and in particular, a remarkable effect can be obtained in a copying machine or a printer having static elimination light.

The method for producing a photoreceptor of the present invention includes a step of forming a coating liquid on a conductive substrate to form at least one of one or more functional layers including a photosensitive layer. The liquid is characterized by containing the red dye compound. In the production method of the present invention, the coating solution can be applied to various coating methods such as a dip coating method or a spray coating method, and is not limited to any coating method.

(Negatively charged laminate type electrophotographic photoreceptor)
Example 1
Dissolve 5 parts by mass of alcohol-soluble nylon (Amilan CM8000, manufactured by Toray Industries, Inc.) and 5 parts by mass of aminosilane-treated titanium oxide fine particles in 90 parts by mass of methanol on the outer periphery of an aluminum cylinder as a conductive substrate. The coating solution prepared by dispersion was dip-coated and dried at a temperature of 100 ° C. for 30 minutes to form an undercoat layer having a thickness of about 2 μm.

On this undercoat layer, 1.5 parts by mass of Y-type titanyl phthalocyanine described in JP-A No. 64-17066 or US Pat. No. 4,898,799 as a charge generation material, and polyvinyl butyral (ESREC) as a resin binder B BX-1, Shin-Etsu Polymer Co., Ltd. (1.5 parts by mass) is immersed in an equivalent mixture of dichloromethane and dichloroethane in 60 parts by mass with a sand mill disperser for 1 hour. It was coated and dried at a temperature of 80 ° C. for 30 minutes to form a charge generation layer having a thickness of about 0.3 μm.

On this charge generation layer, 100 parts by mass of the compound represented by the structural formula IV (II-1) as a charge transport material and polycarbonate resin (Panlite TS-2050, manufactured by Teijin Chemicals Ltd.) 100 as a resin binder Next, 0.1 part by mass of silicone oil (KP-340, manufactured by Shin-Etsu Polymer Co., Ltd.) is added to 1 part by mass as a red dye compound according to the present invention. A coating solution prepared by adding 0.2 parts by mass of [4- (phenylazo) phenylazo] -2-naphthol (manufactured by Hakka Kasei Co., Ltd.) was applied to form a film, and dried at a temperature of 90 ° C. for 60 minutes. A charge transport layer having a thickness of about 25 μm was formed to produce an electrophotographic photoreceptor.

Example 2
Instead of 1- [4- (phenylazo) phenylazo] -2-naphthol, 1- [2-methyl-4- (2-methylphenylazo) phenylazo] -2-naphthol (manufactured by Hakko Kasei Co., Ltd.) was used. A photoconductor was prepared in the same manner as in Example 1 except that it was used.

Example 3
Example 1 except that 1- (2,4-dimethylphenylazo) -2-naphthol (manufactured by Daiwa Kasei Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol. Similarly, a photoreceptor was produced.

Example 4
A photoconductor was prepared in the same manner as in Example 1 except that naphthol red (manufactured by Daiwa Kasei Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 5
A photoconductor was prepared in the same manner as in Example 1 except that Acid Red 26 (manufactured by Kiriya Chemical Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 6
A photoconductor was prepared in the same manner as in Example 1 except that erythrosine B (manufactured by Kiriya Chemical Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 7
A photoconductor was prepared in the same manner as in Example 1, except that Rossellin (manufactured by Sanei Chemical Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 8
A photoconductor was prepared in the same manner as in Example 1 except that rhodamine B acetate (manufactured by Sanei Chemical Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 9
A photoconductor was prepared in the same manner as in Example 1 except that rhodamine B stearate (manufactured by Kiriya Chemical Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 10
A photoconductor was prepared in the same manner as in Example 1 except that tetrabromofluorescein (manufactured by Daiwa Kasei Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 11
A photoconductor was prepared in the same manner as in Example 1 except that tetrachlorofluorescein (manufactured by Daiwa Kasei Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 12
A photoconductor was prepared in the same manner as in Example 1, except that eosin blue was (manufactured by Sanei Chemical Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 13
A photoconductor was prepared in the same manner as in Example 1 except that rose bengal (manufactured by Hakko Kasei Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 14
A photoconductor was prepared in the same manner as in Example 1 except that Sudan IV (manufactured by Hakko Kasei Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 15
A photoconductor was prepared in the same manner as in Example 1 except that Bonso 3R (manufactured by Kiriya Chemical Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 16
A photoconductor was prepared in the same manner as in Example 1 except that Bonso 4R (manufactured by Kiriya Chemical Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 17
A photoconductor was prepared in the same manner as in Example 1 except that Bonso SX (manufactured by Sanei Chemical Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 18
A photoconductor was prepared in the same manner as in Example 1 except that xylene red (manufactured by Sanei Chemical Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 19
A photoconductor was prepared in the same manner as in Example 1 except that Phloxin B (manufactured by Daiwa Kasei Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 20
A photoconductor was prepared in the same manner as in Example 1 except that eosin (manufactured by Daiwa Kasei Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 21
A photoconductor was prepared in the same manner as in Example 1 except that the charge transporting material was changed to the compound represented by the structural formula (II-6).

Example 22
Instead of 1- [4- (phenylazo) phenylazo] -2-naphthol, 1- [2-methyl-4- (2-methylphenylazo) phenylazo] -2-naphthol (manufactured by Hakko Kasei Co., Ltd.) was used. A photoreceptor was prepared in the same manner as in Example 21 except that it was used.

Example 23
Example 21 is the same as Example 21 except that 1- (2,4-dimethylphenylazo) -2-naphthol (manufactured by Daiwa Kasei Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol. Similarly, a photoreceptor was produced.

Example 24
A photoconductor was prepared in the same manner as in Example 21, except that naphthol red (manufactured by Daiwa Kasei Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 25
A photoconductor was prepared in the same manner as in Example 21, except that Acid Red 26 (manufactured by Kiriya Chemical Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 26
A photoconductor was prepared in the same manner as in Example 21, except that erythrosine B (manufactured by Kiriya Chemical Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 27
A photoconductor was prepared in the same manner as in Example 21, except that Rossellin (manufactured by Sanei Chemical Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 28
A photoconductor was prepared in the same manner as in Example 21, except that rotamine B acetate (manufactured by Sanei Chemical Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 29
A photoconductor was prepared in the same manner as in Example 21, except that rotamine B stearate (manufactured by Kiriya Chemical Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 30
A photoconductor was prepared in the same manner as in Example 21, except that tetrabromofluorescein (manufactured by Daiwa Kasei Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 31
A photoconductor was prepared in the same manner as in Example 21, except that tetrachlorofluorescein (manufactured by Daiwa Kasei Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 32
A photoconductor was prepared in the same manner as in Example 21, except that eosin blue was (manufactured by Sanei Chemical Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 33
A photoconductor was prepared in the same manner as in Example 21, except that rose bengal (manufactured by Hakko Kasei Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 34
A photoconductor was prepared in the same manner as in Example 21, except that Sudan IV (manufactured by Hakko Kasei Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 35
A photoconductor was prepared in the same manner as in Example 21 except that Bonso 3R (manufactured by Kiriya Chemical Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 36
A photoconductor was prepared in the same manner as in Example 21 except that Bonso 4R (manufactured by Kiriya Chemical Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 37
A photoconductor was prepared in the same manner as in Example 21, except that Bonso SX (manufactured by Sanei Chemical Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 38
A photoconductor was prepared in the same manner as in Example 21, except that xylene red (manufactured by Sanei Chemical Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 39
A photoconductor was prepared in the same manner as in Example 21 except that Phloxin B (manufactured by Daiwa Kasei Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 40
A photoconductor was prepared in the same manner as in Example 21, except that eosin (manufactured by Daiwa Kasei Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 41
To the charge generation layer used in Example 1, 0.02 part by mass of 1- [4- (phenylazo) phenylazo] -2-naphthol (manufactured by Hakka Kasei Co., Ltd.) was added, and 1- [4 An electrophotographic photoreceptor was prepared in the same manner as in Example 1 except that-(phenylazo) phenylazo] -2-naphthol was not added.

Example 42
Instead of 1- [4- (phenylazo) phenylazo] -2-naphthol, 1- [2-methyl-4- (2-methylphenylazo) phenylazo] -2-naphthol (manufactured by Hakko Kasei Co., Ltd.) was used. An electrophotographic photoreceptor was produced in the same manner as in Example 41 except that it was used.

Example 43
Example 1 is the same as Example 41 except that 1- [2,4-dimethylphenylazo) -2-naphthol (manufactured by Daiwa Kasei Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol. Similarly, a photoreceptor was produced.

Example 44
A photoconductor was prepared in the same manner as in Example 41 except that naphthol red (produced by Daiwa Kasei Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 45
A photoconductor was prepared in the same manner as in Example 41 except that Acid Red 26 (manufactured by Kiriya Chemical Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 46
A photoconductor was prepared in the same manner as in Example 41 except that erythrosine B (manufactured by Kiriya Chemical Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 47
A photoreceptor was produced in the same manner as in Example 41 except that Rossellin (manufactured by Sanei Chemical Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 48
A photoconductor was prepared in the same manner as in Example 41 except that rotamine B acetate (manufactured by Sanei Chemical Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 49
A photoconductor was prepared in the same manner as in Example 41 except that rotamine B stearate (manufactured by Kiriya Chemical Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 50
A photoconductor was prepared in the same manner as in Example 41 except that tetrabromofluorescein (manufactured by Daiwa Kasei Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 51
A photoconductor was prepared in the same manner as in Example 41 except that tetrachlorofluorescein (manufactured by Daiwa Kasei Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 52
A photoconductor was prepared in the same manner as in Example 41 except that eosin blue was (manufactured by Sanei Chemical Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 53
A photoconductor was prepared in the same manner as in Example 41 except that rose bengal (manufactured by Hatsuka Kasei Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 54
A photoconductor was prepared in the same manner as in Example 41 except that Sudan IV (manufactured by Hatsuka Kasei Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 55
A photoconductor was prepared in the same manner as in Example 41 except that Bonso 3R (manufactured by Kiriya Chemical Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 56
A photoconductor was prepared in the same manner as in Example 41 except that Bonso 4R (manufactured by Kiriya Chemical Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 57
A photoconductor was prepared in the same manner as in Example 41 except that Bonso SX (manufactured by Sanei Chemical Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 58
A photoconductor was prepared in the same manner as in Example 41 except that xylene red (manufactured by Sanei Chemical Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 59
A photoconductor was prepared in the same manner as in Example 41 except that Phloxin B (manufactured by Daiwa Kasei Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 60
A photoconductor was prepared in the same manner as in Example 41 except that eosin (manufactured by Daiwa Kasei Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 61
0.02 parts by mass of 1- [4- (phenylazo) phenylazo] -2-naphthol (manufactured by Hakka Kasei Co., Ltd.) was added to the subbing layer used in Example 1, and 1- [4 An electrophotographic photoreceptor was prepared in the same manner as in Example 1 except that-(phenylazo) phenylazo] -2-naphthol was not added.

Example 62
Instead of 1- [4- (phenylazo) phenylazo] -2-naphthol, 1- [2-methyl-4- (2-methylphenylazo) phenylazo] -2-naphthol (manufactured by Hakko Kasei Co., Ltd.) was used. An electrophotographic photoreceptor was produced in the same manner as in Example 61 except that it was used.

Example 63
Example 61 is the same as Example 61 except that 1- [2,4-dimethylphenylazo) -2-naphthol (manufactured by Daiwa Kasei Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol. Similarly, a photoreceptor was produced.

Example 64
A photoconductor was prepared in the same manner as in Example 61 except that naphthol red (manufactured by Daiwa Kasei Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 65
A photoconductor was prepared in the same manner as in Example 61 except that Acid Red 26 (manufactured by Kiriya Chemical Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 66
A photoconductor was prepared in the same manner as in Example 61 except that erythrosine B (manufactured by Kiriya Chemical Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 67
A photoconductor was prepared in the same manner as in Example 61 except that roselin (manufactured by Sanei Chemical Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 68
A photoconductor was prepared in the same manner as in Example 61 except that rotamine B acetate (manufactured by Sanei Chemical Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 69
A photoconductor was prepared in the same manner as in Example 61 except that rotamine B stearate (manufactured by Kiriya Chemical Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 70
A photoconductor was prepared in the same manner as in Example 61 except that tetrabromofluorescein (manufactured by Daiwa Kasei Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 71
A photoconductor was prepared in the same manner as in Example 61 except that tetrachlorofluorescein (manufactured by Daiwa Kasei Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 72
A photoconductor was prepared in the same manner as in Example 61 except that eosin blue isch (manufactured by Sanei Chemical Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 73
A photoconductor was prepared in the same manner as in Example 61 except that rose bengal (manufactured by Hatsuka Kasei Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 74
A photoconductor was prepared in the same manner as in Example 61 except that Sudan IV (manufactured by Hakko Kasei Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 75
A photoconductor was prepared in the same manner as in Example 61 except that Bonso 3R (manufactured by Kiriya Chemical Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 76
A photoconductor was prepared in the same manner as in Example 61 except that Bonso 4R (manufactured by Kiriya Chemical Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 77
A photoconductor was prepared in the same manner as in Example 61 except that Bonso SX (manufactured by Sanei Chemical Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 78
A photoconductor was prepared in the same manner as in Example 61 except that xylene red (manufactured by Sanei Chemical Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 79
A photoconductor was prepared in the same manner as in Example 61 except that Phloxin B (manufactured by Daiwa Kasei Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 80
A photoconductor was prepared in the same manner as in Example 61 except that eosin (manufactured by Daiwa Kasei Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 81
A film obtained by removing 1- [4- (phenylazo) phenylazo] -2-naphthol and silicone oil (KP-340, manufactured by Shin-Etsu Polymer Co., Ltd.) according to the present invention from the coating solution for charge transport layer used in Example 1. A charge transport layer was formed in the same manner as in Example 1 except that the thickness was set to 20 μm, and further, 80 parts by mass of the compound represented by the structural formula (II-1) as a charge transport material and a resin binder were further formed thereon. And 120 parts by mass of polycarbonate resin (PCZ-500, manufactured by Mitsubishi Gas Chemical Co., Ltd.) as dissolved in 900 parts by mass of dichloromethane, and 0.1 mass of silicone oil (KP-340, manufactured by Shin-Etsu Polymer Co., Ltd.). In addition, a coating solution prepared by adding 0.2 parts by mass of 1- [4- (phenylazo) phenylazo] -2-naphthol according to the present invention was applied to form a film. And dried for 60 minutes in degrees 90 ° C., to form a surface protective layer having a thickness of about 10 [mu] m, to prepare an electrophotographic photoreceptor.

Example 82
Instead of 1- [4- (phenylazo) phenylazo] -2-naphthol, 1- [2-methyl-4- (2-methylphenylazo) phenylazo] -2-naphthol (manufactured by Hakko Kasei Co., Ltd.) was used. An electrophotographic photoreceptor was produced in the same manner as in Example 81 except that it was used.

Example 83
Example 1 is the same as Example 81 except that 1- [2,4-dimethylphenylazo) -2-naphthol (produced by Daiwa Kasei Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol. Similarly, a photoreceptor was produced.

Example 84
A photoconductor was prepared in the same manner as in Example 81 except that naphthol red (manufactured by Daiwa Kasei Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 85
A photoconductor was prepared in the same manner as in Example 81 except that Acid Red 26 (manufactured by Kiriya Chemical Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 86
A photoconductor was prepared in the same manner as in Example 81 except that erythrosine B (manufactured by Kiriya Chemical Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 87
A photoconductor was prepared in the same manner as in Example 81 except that Rossellin (manufactured by Sanei Chemical Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 88
A photoconductor was prepared in the same manner as in Example 81 except that rotamine B acetate (manufactured by Sanei Chemical Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 89
A photoconductor was prepared in the same manner as in Example 81 except that rotamine B stearate (manufactured by Kiriya Chemical Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 90
A photoconductor was prepared in the same manner as in Example 81 except that tetrabromofluorescein (manufactured by Daiwa Kasei Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 91
A photoconductor was prepared in the same manner as in Example 81 except that tetrachlorofluorescein (manufactured by Daiwa Kasei Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 92
A photoconductor was prepared in the same manner as in Example 81 except that eosin blue was (manufactured by Sanei Chemical Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 93
A photoconductor was prepared in the same manner as in Example 81 except that rose bengal (manufactured by Hatsuka Kasei Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 94
A photoconductor was prepared in the same manner as in Example 81 except that Sudan IV (manufactured by Hakko Kasei Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 95
A photoconductor was prepared in the same manner as in Example 81 except that Bonso 3R (manufactured by Kiriya Chemical Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 96
A photoconductor was prepared in the same manner as in Example 81 except that Bonso 4R (manufactured by Kiriya Chemical Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 97
A photoconductor was prepared in the same manner as in Example 81 except that Bonso SX (manufactured by Sanei Chemical Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 98
A photoconductor was prepared in the same manner as in Example 81 except that xylene red (manufactured by Sanei Chemical Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 99
A photoconductor was prepared in the same manner as in Example 81 except that Phloxin B (manufactured by Daiwa Kasei Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 100
A photoconductor was prepared in the same manner as in Example 81 except that eosin (manufactured by Daiwa Kasei Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 101
In the same manner as in Example 1, except that the charge generation material used in Example 1 was replaced with α-type titanyl phthalocyanine described in JP-A-61-217050 or US Pat. No. 4,728,592 A photoconductor was prepared.

Example 102
Instead of 1- [4- (phenylazo) phenylazo] -2-naphthol, 1- [2-methyl-4- (2-methylphenylazo) phenylazo] -2-naphthol (manufactured by Hakko Kasei Co., Ltd.) was used. An electrophotographic photoreceptor was produced in the same manner as in Example 101 except that it was used.

Example 103
Example 101 is the same as Example 101 except that 1- (2,4-dimethylphenylazo) -2-naphthol (manufactured by Daiwa Kasei Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol. Similarly, a photoreceptor was produced.

Example 104
A photoconductor was prepared in the same manner as in Example 101 except that naphthol red (manufactured by Daiwa Kasei Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 105
A photoconductor was prepared in the same manner as in Example 101 except that Acid Red 26 (manufactured by Kiriya Chemical Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 106
A photoconductor was prepared in the same manner as in Example 101 except that erythrosine B (manufactured by Kiriya Chemical Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 107
An electrophotographic photoreceptor was prepared in the same manner as in Example 1 except that the charge generation material used in Example 1 was replaced with X-type metal-free phthalocyanine (Dainippon Ink Chemical Co., Ltd., Fastogen Blue 10120B). Produced.

Example 108
Instead of 1- [4- (phenylazo) phenylazo] -2-naphthol, 1- [2-methyl-4- (2-methylphenylazo) phenylazo] -2-naphthol (manufactured by Hakko Kasei Co., Ltd.) was used. An electrophotographic photoreceptor was produced in the same manner as in Example 107 except that it was used.

Example 109
Example 107 is the same as Example 107 except that 1- (2,4-dimethylphenylazo) -2-naphthol (manufactured by Daiwa Kasei Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol. Similarly, a photoreceptor was produced.

Example 110
A photoconductor was prepared in the same manner as in Example 107 except that naphthol red (manufactured by Daiwa Kasei Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 111
A photoconductor was prepared in the same manner as in Example 107 except that Acid Red 26 (manufactured by Kiriya Chemical Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 112
A photoconductor was prepared in the same manner as in Example 107 except that erythrosine B (manufactured by Kiriya Chemical Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Comparative Example 1
A photoconductor was prepared in the same manner as in Example 1 except that 1- [4- (phenylazo) phenylazo] -2-naphthol was not added.

Comparative Example 2
Instead of 1- [4- (phenylazo) phenylazo] -2-naphthol, which is a red dye compound, 2- (2-quinolyl) -1,3-indandinone (manufactured by Sakai Kasei Co., Ltd.), which is a yellow dye compound, is used. A photoconductor was prepared in the same manner as in Example 1 except that 0.2 part by mass was added.

Comparative Example 3
A photoconductor was prepared in the same manner as in Example 21 except that 1- [4- (phenylazo) phenylazo] -2-naphthol was not added.

Comparative Example 4
A photoconductor was prepared in the same manner as in Example 41 except that 1- [4- (phenylazo) phenylazo] -2-naphthol was not added.

Comparative Example 5
A photoconductor was prepared in the same manner as in Example 61 except that 1- [4- (phenylazo) phenylazo] -2-naphthol was not added.

Comparative Example 6
A photoconductor was prepared in the same manner as in Example 81 except that 1- [4- (phenylazo) phenylazo] -2-naphthol was not added.

Comparative Example 7
A photoconductor was prepared in the same manner as in Example 101 except that 1- [4- (phenylazo) phenylazo] -2-naphthol was not added.

The photoconductors produced in Examples 1-112 and Comparative Examples 1-7 were mounted on LJ4250 manufactured by HP and evaluated by the following methods. That is, the surface of the photosensitive member was charged to −650 V by corona discharge in the dark, and then the surface potential V0 immediately after charging was measured. Subsequently, the corona discharge was stopped and the surface potential V5 was measured after being left in the dark for 5 seconds, and the potential holding rate Vk5 (%) after 5 seconds after charging was determined according to the following formula (1).
Vk5 = V5 / V0 × 100 (1)

Similarly, after the surface of the photoconductor is charged to about −650 V, irradiation with light of 780 nm and 1 μW / cm ² is continued, and the exposure amount E1 / 2 required for the potential to decay from −600 V to −300 V is obtained. It was measured. Furthermore, the residual potential Vr5 after 5 seconds of irradiation was measured.

Further, as the light fatigue characteristics, the photoreceptor was left under a 1500 (lx · s) fluorescent lamp for 10 minutes, and the potential before and after the standing was measured using a photoreceptor drum electrical property evaluation apparatus. As for the potential in the photofatigue property, the surface of the photosensitive member is charged to about −600 V while rotating the drum, and the charged potential V0 is measured, followed by irradiation with light of 780 nm and ² μW / cm ² for 0.25 seconds. Then, the bright part potential VL was measured.

The electrical characteristics of the photoreceptors produced in Examples 1-112 and Comparative Examples 1-7 are shown in the table below. In the following table, “front” and “rear” mean before and after leaving, respectively.

(Positively charged single layer type electrophotographic photoreceptor)
Example 113
Dissolve and disperse 5 parts by mass of alcohol-soluble nylon (Amilan CM8000, manufactured by Toray Industries, Inc.) and 5 parts by mass of aminosilane-treated titanium oxide fine particles in 90 parts by mass of methanol on the outer periphery of an aluminum cylinder as a conductive substrate. The coating solution thus prepared was dip-coated and dried at a temperature of 100 ° C. for 30 minutes to form an undercoat layer having a thickness of about 2 μm.

On this undercoat layer, 7.0 parts by mass of a styryl compound represented by the structural formula (II-12) as a hole transport material and a compound 3 represented by the following compound (III-1) as an electron transport material 9.6 parts by mass of polycarbonate resin (Panlite TS-2050, manufactured by Teijin Chemicals Ltd.) as a resin binder, 0.04 part by mass of silicone oil (KF-54, manufactured by Shin-Etsu Polymer Co., Ltd.) And 0.02 parts by mass of 1- [4- (phenylazo) phenylazo] -2-naphthol (manufactured by Hakka Kasei Co., Ltd.) as a red dye compound according to the present invention are dissolved in 100 parts by mass of methylene chloride. By adding 0.3 parts by mass of an X-type metal-free phthalocyanine described in JP-A-2001-228737 as a charge generation material, a dispersion treatment is performed using a sand grind mill. The coating solution manufactured by film-forming, to form a single-layer photosensitive layer having a thickness of about 25μm by drying 60 minutes at a temperature 100 ° C., to obtain a positively charged monolayer type electrophotographic photoconductor.

Example 114
Instead of 1- [4- (phenylazo) phenylazo] -2-naphthol, 1- [2-methyl-4- (2-methylphenylazo) phenylazo] -2-naphthol (manufactured by Hakko Kasei Co., Ltd.) was used. A photoconductor was prepared in the same manner as Example 113 except that it was used.

Example 115
Example 1 except that 1- (2,4-dimethylphenylazo) -2-naphthol (manufactured by Daiwa Kasei Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol. Similarly, a photoreceptor was produced.

Example 116
A photoconductor was prepared in the same manner as in Example 113 except that naphthol red (manufactured by Daiwa Kasei Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 117
A photoconductor was prepared in the same manner as in Example 113 except that Acid Red 26 (manufactured by Kiriya Chemical Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 118
A photoconductor was prepared in the same manner as in Example 113 except that erythrosine B (manufactured by Kiriya Chemical Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 119
A photoconductor was prepared in the same manner as in Example 113 except that Rossellin (manufactured by Sanei Chemical Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 120
A photoconductor was prepared in the same manner as in Example 113 except that rotamine B acetate (manufactured by Sanei Chemical Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 121
A photoconductor was prepared in the same manner as in Example 113 except that rotamine B stearate (manufactured by Kiriya Chemical Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 122
A photoconductor was prepared in the same manner as in Example 113 except that tetrabromofluorescein (manufactured by Daiwa Kasei Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 123
A photoconductor was prepared in the same manner as in Example 113 except that tetrachlorofluorescein (manufactured by Daiwa Kasei Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 124
A photoconductor was prepared in the same manner as in Example 113 except that eosin blue was (manufactured by Sanei Chemical Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 125
A photoconductor was prepared in the same manner as in Example 113 except that rose bengal (manufactured by Hakko Kasei Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 126
A photoconductor was prepared in the same manner as in Example 113 except that Sudan IV (manufactured by Hakko Kasei Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 127
A photoconductor was prepared in the same manner as in Example 113 except that Bonso 3R (manufactured by Kiriya Chemical Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 128
A photoconductor was prepared in the same manner as in Example 113 except that Bonso 4R (manufactured by Kiriya Chemical Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 129
A photoconductor was prepared in the same manner as in Example 113 except that Bonso SX (manufactured by Sanei Chemical Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 130
A photoconductor was prepared in the same manner as in Example 113 except that xylene red (manufactured by Sanei Chemical Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 131
A photoconductor was prepared in the same manner as in Example 113 except that Phloxin B (manufactured by Daiwa Kasei Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Example 132
A photoconductor was prepared in the same manner as in Example 113 except that eosin (manufactured by Daiwa Kasei Co., Ltd.) was used instead of 1- [4- (phenylazo) phenylazo] -2-naphthol.

Comparative Example 8
An electrophotographic photoreceptor was produced in the same manner as in Example 113 except that 1- [4- (phenylazo) phenylazo] -2-naphthol was not used.

Comparative Example 9
Instead of 1- [4- (phenylazo) phenylazo] -2-naphthol as a red dye compound, 2- (2-quinolyl) -1,3-indandinone (manufactured by Sakai Kasei Co., Ltd.) as a yellow dye compound A photoconductor was prepared in the same manner as in Example 113 except that 0.02 part by mass was added.

The photoreceptors prepared in Examples 113 to 132 and Comparative Examples 8 and 9 were mounted on a printer HL-2040 manufactured by Brother Co., Ltd., and evaluated by the following method. That is, the surface of the photosensitive member was charged to +650 V by corona discharge in a dark place, and then the surface potential V0 immediately after charging was measured. Subsequently, the corona discharge was stopped and the surface potential V5 was measured after being left in the dark for 5 seconds, and the potential holding rate Vk5 (%) after 5 seconds after charging was determined according to the following formula (2).
Vk5 = V5 / V0 × 100 (2)

Similarly, the surface of the photosensitive member was charged to about 650 V, irradiated with light of 780 nm and 1 μW / cm ² , and the exposure amount E1 / 2 required for the potential to attenuate from 600 V to 300 V was measured. Further, the residual potential Vr5 after 5 seconds of irradiation was measured.

Further, as the light fatigue characteristics, the photoreceptor was left under a 1500 (lx · s) fluorescent lamp for 10 minutes, and the potential before and after the standing was measured using a photoreceptor drum electrical property evaluation apparatus. The potential in the light fatigue characteristics is measured by charging the surface of the photoreceptor to about +600 V while rotating the drum and measuring the charged potential V0, followed by irradiation with light of 780 nm, ² μW / cm ² for 0.25 seconds. Then, the bright part potential VL was measured.

From the results in the above table, it was confirmed that in the photoreceptor using the red dye compound according to the present invention, light fatigue was prevented without causing deterioration of electrophotographic characteristics such as sensitivity and residual potential. . Therefore, the superiority of the photoreceptor of the present invention using a red dye compound for the purpose of suppressing photodegradation is clear.

According to the present invention, by containing a red dye compound in the undercoat layer, the photosensitive layer, or the surface protective layer, blue light or ultraviolet light having strong chemical activity is absorbed or blocked, and electrophotography such as sensitivity and residual potential is obtained. An electrophotographic photoreceptor free from light fatigue can be obtained without affecting the characteristics.

DESCRIPTION OF SYMBOLS 1 Conductive base | substrate 2 Undercoat layer 3 Photosensitive layer 4 Charge generation layer 5 Charge transport layer 6 Surface protective layer

Claims

An electrophotographic photoreceptor comprising one or more functional layers including a photosensitive layer on a conductive substrate, wherein at least one of the functional layers contains a red dye compound. Photoconductor.
The electrophotographic photoreceptor according to claim 1, wherein the photosensitive layer contains the red dye compound.
2. The electrophotographic photoreceptor according to claim 1, wherein the functional layer includes an undercoat layer, and the undercoat layer contains the red dye compound.
3. The electrophotographic photoreceptor according to claim 2, wherein the photosensitive layer includes a charge generation layer, and the charge generation layer contains the red dye compound.
3. The electrophotographic photoreceptor according to claim 2, wherein the photosensitive layer includes a charge transport layer, and the charge transport layer contains the red dye compound.
The electrophotographic photoreceptor according to claim 1, wherein the functional layer includes a surface protective layer, and the surface protective layer contains the red dye compound.
The electrophotographic photoreceptor according to claim 2, wherein the photosensitive layer is a single positively charged photosensitive layer.
The electrophotographic photoreceptor according to any one of claims 1 to 7, wherein the red dye compound is at least one selected from a compound containing a hydroxynaphthylazo group and a compound having a xanthene or xanthine skeleton.
The red dye compound is 1- [4- (phenylazo) phenylazo] -2-naphthol, 1- (2,4-dimethylphenylazo) -2-naphthol, eosin blue ish, rose bengal, sudan IV, bon so 3R, Bonso 4R, Bonso SX, Xylene Red, Naphthol Red, Acid Red 26, Erythrosin B, Phloxine B, Eosin, Rossellin, Rhodamine B Acetate, Rhodamine B Stearate, Tetrabromofluorescein, and Tetrachlorofluorescein The electrophotographic photoreceptor according to claim 8, which is at least one kind.
The electrophotographic photoreceptor according to claim 1, wherein the amount of the red dye compound added is 3 parts by mass or less based on 100 parts by mass of the resin binder in the layer to be used.
In a method for producing an electrophotographic photoreceptor, comprising a step of applying a coating solution on a conductive substrate to form at least one of one or more functional layers including a photosensitive layer. A method for producing an electrophotographic photoreceptor, comprising a red dye compound.