JP2010181911A - Electrophotographic photoreceptor and electrophotographic device using same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor causing no image defect and having excellent potential stability, high durability and excellent resistance to light fatigue, and to provide an electrophotographic device equipped with the electrophotographic photoreceptor. <P>SOLUTION: The electrophotographic photoreceptor includes at least a charge generating layer and a charge transferring layer formed on a conductive substrate. The charge generating layer contains two or more kinds of charge generating substances having the spectral sensitivity characteristics in different spectral regions of a visible ray region and a near IR region. The charge transferring layer contains a compound having an absorption peak at 450-620 nm. The compound contained in the charge transferring layer is a naphthoquinone or an anthraquinone derivative. The electrophotographic photoreceptor is mounted in the electrophotographic device. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an electrophotographic photosensitive member and an electrophotographic apparatus using the same, and more specifically, an electrophotographic photosensitive member that is excellent in potential stability and light fatigue when repeatedly used and does not generate abnormal images such as black spots. The present invention relates to a body and an electrophotographic apparatus using the body.

  Conventionally, inorganic materials such as Se, CdS, and ZnO have been used as photoconductive materials for electrophotographic photoreceptors. However, since they have problems such as photosensitivity, thermal stability, toxicity, etc. Development of electrophotographic photoreceptors using conductive materials has been actively conducted, and electrophotographic photoreceptors having a photosensitive layer containing a charge generation material and a charge transport material have already been put into practical use. . On the other hand, from the viewpoint of the emergence of electrophotographic devices that use semiconductor lasers as the light source, such as laser printers and digital copiers, and the common use of photoconductors, electrophotographic photoconductors have a wide range of spectral sensitivity characteristics from the visible to the near infrared region. It is beginning to be required to have.

  Conventionally, it has been proposed to use two or more types of pigments having spectral sensitivity characteristics in different spectral regions as charge generating materials used in such a photoreceptor (Japanese Patent Laid-Open Nos. 63-148264 and 01). No. 1,775,534 and JP-A-01-270050). However, by using two or more kinds of pigments as charge generation materials, the spectral sensitivity range is widened, but conversely, by creating two or more energy levels in the charge generation layer, the characteristics of the pigments themselves cannot be utilized, and the prescription surface Therefore, it is difficult to achieve both an increase in the residual potential and a decrease in the charging potential.

  In addition, although it is considered that there are two or more energy levels, there is a large deterioration in the withstand voltage characteristics due to light irradiation, and problems such as generation of background stains and black spots remain on the image. To prevent such light fatigue and black spots, an antioxidant and a photodegradation inhibitor should be added as disclosed in JP-A-57-122444 and JP-A-63-18355. Has been proposed. However, it is not practical and practical for a photoreceptor using two or more pigments having spectral sensitivity characteristics in different spectral regions. For preventing light degradation, as described in JP-A-10-228121, JP-B-8-33660, JP-A-11-184108, JP-A-10-63022, and the like, It has been shown to add an orange dye to the charge transport layer. However, these are limited to phthalocyanine pigments or specific charge transport materials, and there is no description for a photoreceptor using two or more kinds of pigments having spectral sensitivity characteristics in different spectral regions. Further, effects other than prevention of light degradation are not described.

  An object of the present invention is to solve the conventional problems. Accordingly, an object of the present invention is to provide an electrophotographic photosensitive member having no image defects and excellent in stability on potential and having high durability and excellent resistance to light fatigue, and an electrophotographic apparatus including the electrophotographic photosensitive member. It is to provide.

  As a result of intensive studies on the above problems, the present inventors have found that an electrophotographic photoreceptor that is highly durable and resistant to light fatigue by containing a compound having an absorption peak at 450 to 620 nm in the charge transport layer. As a result, the present invention has been completed. That is, according to the present invention,

  First, in an electrophotographic photosensitive member in which at least a charge generation layer and a charge transport layer are laminated on a conductive support, the charge generation layer has spectral sensitivity characteristics in different spectral regions in the visible region and the near infrared region. There is provided an electrophotographic photoreceptor comprising a charge generating material containing at least one kind and a compound having an absorption peak at 450 to 620 nm in the charge transport layer.

  Secondly, in the electrophotographic photosensitive member described in the first aspect, the charge generating material having spectral sensitivity characteristics in the visible range is an asymmetric disazo pigment represented by the following general formula (I): 1 is provided.

(In the formula, A represents a divalent residue bonded to the nitrogen atom of the azo group by a carbon atom. Cp ₁ and Cp ₂ represent coupler residues having different structures.)

  Third, in the electrophotographic photosensitive member described in the first aspect, the charge generating material having spectral sensitivity characteristics in the visible range is a compound represented by the following general formula (II): Is provided.

(In the formula, Cp ₁ and Cp ₂ represent coupler residues having different structures.)

  Fourthly, in the electrophotographic photosensitive member described in the first aspect, an electrophotographic photosensitive member is provided in which the charge generating material having spectral sensitivity characteristics in the near infrared region is a phthalocyanine pigment.

  Fifth, in the electrophotographic photosensitive member described in the first, the compound having an absorption peak at 450 to 620 nm contained in the charge transport layer is a charge generating material having spectral sensitivity characteristics in the visible range. An electrophotographic photosensitive member is provided.

  Sixthly, in the electrophotographic photosensitive member described in the first aspect, the compound having an absorption peak at 450 to 620 nm contained in the charge transport layer is a naphthoquinone or an anthraquinone derivative. Is provided.

  Seventh, there is provided an electrophotographic apparatus characterized in that the electrophotographic photosensitive member described in the first to fifth aspects is attached to an electrophotographic apparatus having at least a charging means, an exposing means, a reversal developing means, and a transferring means. The

  According to the present invention, it is possible to obtain a highly durable electrophotographic photosensitive member that is not deteriorated by light and does not generate black spots or abnormal images, and further provides an electrophotographic apparatus equipped with the photosensitive member. Can do.

FIG. 3 is a cross-sectional view illustrating the layer configuration of the electrophotographic photosensitive member shown in the present invention. FIG. 3 is a cross-sectional view illustrating the layer configuration of the electrophotographic photosensitive member shown in the present invention. FIG. 3 is a cross-sectional view illustrating the layer configuration of the electrophotographic photosensitive member shown in the present invention. 1 is an electrophotographic apparatus shown in the present invention.

  The present invention is described in detail below. As described above, the present invention provides an electrophotographic photosensitive member in which a photosensitive layer containing at least two or more kinds of charge generating materials having spectral sensitivity characteristics in different spectral regions is provided on a conductive support at 450 to 620 nm. By containing a compound having an absorption peak, the above-described effects can be brought about. However, other additives such as hindered phenol antioxidants, phosphorus antioxidants, and photodegradation inhibitors are quite effective. Even if the effect is obtained, only one of the effects of improving the image quality and preventing the light deterioration can be obtained. The reason why the compound of the present invention is excellent is that it effectively acts on the difference in energy gap caused by using two or more kinds of charge generating substances, and has the effect of eliminating and reducing the trap level. The main cause of photodegradation is a charge generation material having spectral sensitivity characteristics in the visible region, and it is considered that the effect can be obtained by effectively removing light in this region. On the other hand, the reason why naphthoquinone or anthraquinone derivatives are more excellent is that they can effectively remove light, have little effect on the characteristics of the photoreceptor, and can be added without increasing the amount. This is considered to be due to reasons such as acting.

As the two or more kinds of charge generating materials having spectral sensitivity characteristics in different spectral regions of the visible region and the near infrared region used in the present invention, general pigments used for a photoreceptor can be used. The charge generation material is not particularly limited. A pyrrole pigment, an anthraquinone pigment, a perylene pigment, a polycyclic quinone pigment, an indigo pigment, a squalium pigment, and other known materials can be used. As the charge generating substance having spectral sensitivity characteristics in the visible region, the above general formula (I It is preferable to use an asymmetric disazo pigment having a very high sensitivity as shown in FIG. These asymmetric disazo pigments are obtained by reacting a corresponding diazonium salt compound and a coupler corresponding to Cp ₁ or Cp ₂ in two steps in sequence, or by a coupling reaction with the first Cp ₁ or Cp ₂ Can be obtained by further reacting the remaining coupler. Examples of A, Cp ₁ and Cp ₂ of these asymmetric disazo pigments are shown in Tables 1 to 9.

  Among these asymmetrical disazo pigments, the compound represented by the general formula (II) having fluorenone as a central skeleton represented by A-20 is particularly preferable from the viewpoint of sensitivity and potential stability.

  As the charge generation material having spectral sensitivity characteristics in the near infrared region, it is preferable to use a phthalocyanine pigment from the viewpoints of sensitivity and light stability. By using the pigment, a sensitization effect can be effectively generated, the spectral sensitivity is wide, and problems such as a residual potential and a decrease in charging potential are hardly caused in terms of electrostatic characteristics. The phthalocyanine pigment is not particularly limited, but all phthalocyanine pigments generally used in electrophotographic photoreceptors can be used, and preferably the X-type metal-free phthalocyanine pigment and τ-type metal-free phthalocyanine shown in the present invention. It is desirable to use a pigment. The reason for this is not clear, but the HOMO level of the metal-free phthalocyanine pigments classified as X-type and τ-type is close to the HOMO level of the above-mentioned asymmetric disazo pigment, and is produced by mixing the pigments by interacting with each other. This is considered to be because the sensitization effect is effectively generated and problems such as a residual potential and a decrease in charging potential are less likely to occur in terms of electrostatic characteristics.

  The τ-type metal-free phthalocyanine pigment has a major peak with a Bragg angle 2θ of 7.6 °, 9.2 °, 16.8 ° in an X-ray diffraction spectrum using Cu-Kα characteristic X-ray (wavelength 1.541Å). 17.4 °, 20.4 °, 20.9 °, 21.7 °, 27.6 ° (each ± 0.2 °), a metal-free phthalocyanine pigment, It can be obtained by the methods described in JP-A-60-19154.

  The X-ray metal-free phthalocyanine pigment has a major peak at a Bragg angle 2θ of 7.5 °, 9.1 °, and 16.7 ° in an X-ray diffraction spectrum using Cu-Kα characteristic X-ray (wavelength 1.541Å). 17.3 °, 22.3 °, and 28.8 ° (each ± 0.2 °) are metal-free phthalocyanine pigments, US Pat. No. 3,357,989, US Pat. No. 3,594,163, Japanese Patent Publication No. 49-4338, and Japanese Patent Application Laid-Open No. 60-60. 243089 and the like.

  As the compound having an absorption peak at 450 to 620 nm, disperse dyes, oil-soluble dyes, and organic pigments having absorption characteristics including the absorption wavelength region can be used, but considering compatibility with the resin, dispersibility, and the like. An azo organic pigment is preferred from the viewpoint of including disperse dyes / pigments and absorption wavelength regions.

  As a specific example, C.I. I. Disperse Orange 5, C.I. I. Disperse Red 116, Celliton Fast PinkFF3B, Mekton Fast Green BL, Meketon Fast Green GL, 1-o-tolylazo-2-naphthol, 5- (9-anthracenylmethylene) amino-3-methyl-4-tolylpyrazole , 5-Diiodo-3,6-fluoranediol, 4,5-dibromo-3,6-fluoranediol, naphthoquinone compound, anthraquinone compound, azo lake compound, triarylmethane compound having at least one amino group, phenol Monoazo compounds having at least one coupler having a hydroxyl group, disazo pigments, polycyclic quinone pigments, perylene pigments, disazo pigments, asymmetric disazo pigments represented by the above general formula (I), heterocyclic rings Cyanine compound having an indoline ring are exemplified by. The present invention will be described below according to the layer structure of the electrophotographic photosensitive member.

  FIG. 1 is a cross-sectional view showing a configuration example of the electrophotographic photosensitive member of the present invention, in which at least a charge generation layer 17 and a charge transport layer 19 are laminated on a conductive support 11. FIG. 2 is a cross-sectional view showing another structural example of the present invention, in which an intermediate layer 13 is provided between the conductive support 11 and the charge generation layer 17. FIG. 3 is a cross-sectional view showing still another structural example of the present invention, in which a protective layer 21 is provided on the charge transport layer 19. In the following, description will be given according to the function separation type configuration shown in FIG. 1, FIG. 2, and FIG.

As the conductive support 11, any material can be used as long as it has a volume resistance of 10 ¹⁰ Ω · cm or less. For example, a metal such as aluminum, nickel, chromium, nichrome, copper, gold, silver, or platinum. , Metal oxides such as tin oxide and indium oxide by vapor deposition or sputtering, film or cylindrical plastic, paper coated, or aluminum, aluminum alloy, nickel, stainless steel, etc. After forming a tube by a method such as the above, a tube subjected to surface treatment such as cutting, superfinishing or polishing can be used. Further, an endless nickel belt and an endless stainless steel belt disclosed in Japanese Patent Application Laid-Open No. 52-36016 can be used as the conductive support 11.

  In addition to this, the conductive support 11 of the present invention can be used in which conductive powder is dispersed and coated on a suitable binder resin. Examples of the conductive powder include carbon black, acetylene black, metal powder such as aluminum, nickel, iron, nichrome, copper, zinc, and silver, or metal oxide such as conductive titanium oxide, conductive tin oxide, and ITO. Examples include powder. The binder resin used simultaneously is polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer. , Polyvinyl acetate, polyvinylidene chloride, polyarylate resin, phenoxy resin, polycarbonate, cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral, polyvinyl formal, polyvinyl toluene, poly-N-vinyl carbazole, acrylic resin, silicone resin, epoxy resin, Examples thereof include thermoplastic, thermosetting resins, and photocurable resins such as melamine resin, urethane resin, phenol resin, and alkyd resin. Such a conductive layer can be provided by dispersing and coating these conductive powder and binder resin in a suitable solvent such as tetrahydrofuran, dichloromethane, 2-butanone, toluene and the like.

  Furthermore, a heat-shrinkable tube containing the conductive powder in a material such as polyvinyl chloride, polypropylene, polyester, polystyrene, polyvinylidene chloride, polyethylene, chlorinated rubber, Teflon (registered trademark) or the like is placed on a suitable cylindrical substrate. Those provided with a conductive layer can also be used favorably as the conductive support 11 of the present invention.

  The charge generation layer 17 contains two or more kinds of charge generation materials having spectral sensitivity characteristics in different spectral regions of the visible region and the near infrared region, and preferably an asymmetric disazo pigment and a phthalocyanine pigment are contained in the binder resin as necessary. Formed in a dispersed manner. Examples of charge generation materials include phthalocyanine pigments such as titanyl phthalocyanine, vanadyl phthalocyanine, copper phthalocyanine, hydroxygallium phthalocyanine, and metal-free phthalocyanine, monoazo pigments, bisazo pigments, asymmetric disazo pigments, trisazo pigments, tetraazo pigments, pyrrolopyrrole pigments, anthraquinone pigments Perylene pigments, polycyclic quinone pigments, indigo pigments, squalium pigments, and other known materials can be used. For the purpose of the present invention, it is desirable to use two or more kinds of charge generating materials having spectral sensitivity characteristics in different spectral regions, preferably in the visible region and the near infrared region, more preferably an asymmetric disazo pigment and a phthalocyanine pigment. Therefore, the charge generation layer 17 is obtained by dispersing these components in a suitable solvent using a ball mill, attritor, sand mill, ultrasonic wave, etc., and applying the dispersion onto the conductive support 11 or the intermediate layer 13 and drying. It is formed by.

  Examples of the binder resin used for the charge generation layer 17 include polyamide, polyurethane, epoxy resin, polyketone, polycarbonate, silicone resin, acrylic resin, polyvinyl formal, polyvinyl butyral, polyvinyl benzal, polyester, phenoxy resin, and vinyl chloride-vinyl acetate. A copolymer, polyvinyl acetate, polyamide, polyvinyl pyridine, cellulose resin, casein, polyvinyl alcohol, polyvinyl pyrrolidone, or the like can be used. As the binder resin used for the charge generation layer 17, it is preferable to use polyvinyl butyral.

  In a more preferable form of the charge generation layer 17, that is, when an asymmetric disazo pigment and a phthalocyanine pigment are contained, the weight ratio thereof is preferably 1/5 or more and 5/1 or less. As a result, even if the phthalocyanine content is high or low, the panchromatic property of the sensitivity is impaired, and the chargeability during electrostatic fatigue is lowered, and the chargeability during light irradiation is lowered. The amount of the binder resin is 10 to 500 parts by weight, preferably 25 to 300 parts by weight, based on 100 parts by weight of the charge generating material. The film thickness of the charge generation layer is 0.01 to 5 μm, preferably 0.1 to 2 μm.

  Solvents used when preparing the charge generation layer coating solution include isopropanol, acetone, methyl ethyl ketone, cyclohexanone, tetrahydrofuran, dioxane, ethyl cellosolve, ethyl acetate, methyl acetate, dichloromethane, dichloroethane, monochlorobenzene, cyclohexane, toluene, xylene, ligroin Etc. As the coating method of the coating solution, methods such as dip coating, spray coating, bead coating, nozzle coating, spinner coating, ring coating, and the like can be used.

  The charge transport layer 19 can be formed by dissolving or dispersing a compound having an absorption peak at 450 to 620 nm, a charge transport material and a binder resin in an appropriate solvent, and applying and drying the solution on the charge generation layer. Moreover, a plasticizer, a leveling agent, antioxidant, etc. can also be added as needed. Charge transport materials include hole transport materials and electron transport materials.

  Examples of the electron transport material include chloroanil, bromanyl, tetracyanoethylene, tetracyanoquinodimethane, 2,4,7-trinitro-9-fluorenone, 2,4,5,7-tetranitro-9-fluorenone, 2, 4,8-trinitrothioxanthone, 2,6,8-trinitro-4H-indeno [1,2-b] thiophen-4-one, 1,3,7-trinitrodibenzothiophene-5,5-dioxide, Examples include electron-accepting substances such as benzoquinone derivatives.

  Examples of hole transport materials include poly-N-vinylcarbazole and derivatives thereof, poly-γ-carbazolylethyl glutamate and derivatives thereof, pyrene-formaldehyde condensates and derivatives thereof, polyvinylpyrene, polyvinylphenanthrene, polysilane, oxazole derivatives, Oxadiazole derivatives, imidazole derivatives, monoarylamine derivatives, diarylamine derivatives, triarylamine derivatives, stilbene derivatives, o-phenylstilbene derivatives, benzidine derivatives, diarylmethane derivatives, triarylmethane derivatives, 9-styrylanthracene derivatives, pyrazolines Derivatives, divinylbenzene derivatives, hydrazone derivatives, indene derivatives, butadiene derivatives, pyrene derivatives, bisstilbene derivatives, enamine derivatives, other polymers Mer of positive holes transporting material such as a known materials.

  Examples of the binder resin used for the charge transport layer include polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyvinylidene chloride, polyarylate, phenoxy resin, polycarbonate, acetic acid. Cellulose resin, ethyl cellulose resin, polyvinyl butyral, polyvinyl formal, polyvinyl toluene, poly-N-vinyl carbazole, acrylic resin, silicone resin, epoxy resin, melamine resin, urethane resin, phenol resin, alkyd resin, JP-A-5-158250 And thermoplastic or thermosetting resins such as various polycarbonate copolymers described in JP-A-6-51544.

  The addition amount of the compound having an absorption peak at 450 to 620 nm is in the range of 0.01 to 10 parts by weight, more preferably 0.05 to 5 parts by weight with respect to 100 parts by weight of the total of the charge transport material and the binder resin. Is desirable.

  The amount of the charge transport material is appropriately 20 to 300 parts by weight, preferably 40 to 150 parts by weight with respect to 100 parts by weight of the binder resin. The thickness of the charge transport layer is preferably about 5 to 50 μm.

  As the solvent used here, tetrahydrofuran, dioxane, toluene, monochlorobenzene, dichloroethane, dichloromethane, cyclohexanone, methyl ethyl ketone, acetone and the like are used.

  In the present invention, a leveling agent may be added to the charge transport layer 19. As the leveling agent, silicone oils such as dimethyl silicone oil and methylphenyl silicone oil, and polymers or oligomers having a perfluoroalkyl group in the side chain can be used, and the amount used is 0 with respect to 100 parts by weight of the binder resin. ˜1 part by weight is suitable.

  In addition, antioxidants may be used in combination, and as antioxidants, oxidation of hindered phenol compounds, sulfur compounds, phosphorus compounds, hindered amine compounds, pyridine derivatives, piperidine derivatives, morpholine derivatives, etc. An inhibitor or the like can be used, and among them, it is preferable to use a hindered phenol compound in combination.

  The intermediate layer 13 is made of a resin-based layer or an anodized oxide film such as alumite, prevents unnecessary charge injection from the conductive substrate to the photosensitive layer, covers defects on the substrate surface, and improves the adhesion of the photosensitive layer. It is provided as needed for the purpose.

  As resin binders, polyethylene, polypropylene, polystyrene, acrylic resin, vinyl chloride resin, vinyl acetate resin, polyurethane resin, epoxy resin, polyester resin, alkyd resin, melamine resin, silicone resin, polyvinyl butyral resin, polyamide resin and their co-polymers Combinations and the like can be used in appropriate combinations.

Further, a fine powder pigment of a metal oxide such as titanium oxide, aluminum oxide, silica, zirconium oxide, tin oxide, or indium oxide may be added to the intermediate layer 13 in order to prevent moire and reduce residual potential. Furthermore, as the intermediate layer 13, a silane coupling agent, a titanium coupling agent, a chromium coupling agent, a titanyl chelate compound, a zirconium chelate compound, a titanyl alkoxide compound, or an organic titanyl compound can be used. These intermediate layers 13 can be formed using an appropriate solvent, dispersion, and coating method as in the above-described photosensitive layer. In addition, the intermediate layer 13 is vacuum-formed with Al ₂ O ₃ provided by anodic oxidation, organic substances such as polyparaxylylene, and inorganic substances such as SiO ₂ , SnO ₂ , TiO ₂ , ITO, and CeO _2. Those provided by the thin film forming method can also be used favorably. The film thickness of the intermediate layer 13 is suitably larger than 0 μm and not larger than 10 μm.

  The protective layer 21 is provided for the purpose of improving the durability of the photoreceptor. Materials used for the protective layer 21 include ABS resin, ACS resin, olefin-vinyl monomer copolymer, chlorinated polyether, allyl resin, phenol resin, Polyacetal, polyamide, polyamideimide, polyacrylate, polyallylsulfone, polybutylene, polybutylene terephthalate, polycarbonate, polyethersulfone, polyethylene, polyethylene terephthalate, polyimide, acrylic resin, polymethylpentene, polypropylene, polyphenylene oxide, polysulfone, polystyrene, AS Examples thereof include resins such as resins, butadiene-styrene copolymers, polyurethane, polyvinyl chloride, polyvinylidene chloride, and epoxy resins. In addition, for the purpose of improving wear resistance, the protective layer 21 can be added with a fluorine resin such as polytetrafluoroethylene, a silicone resin, or an inorganic material such as titanium oxide, tin oxide, or potassium titanate.

  As a method for forming the protective layer 21, a normal coating method can be used. The thickness of the protective layer 21 is suitably 0.1 to 10 μm. In addition to the above, a known material such as a-C or a-SiC formed by a vacuum thin film manufacturing method can also be used as the protective layer 21. In the present invention, another intermediate layer (not shown) may be provided between the photosensitive layer 15 and the protective layer 21. The other intermediate layer generally uses a resin as a main component. Examples of these resins include polyamide, alcohol-soluble nylon resin, water-soluble butyral resin, polyvinyl butyral, and polyvinyl alcohol. As the method for forming the other intermediate layer, as described above, a normal coating method can be used. In addition, 0.05-2 micrometers is suitable for a film thickness.

  The electrophotographic apparatus according to the present invention includes at least charging, exposure, reversal development, and transfer means, and any means can be used for any means that is usually used. As the charging method, for example, corotron using corona discharge, scorotron charging, contact charging with a conductive roller, brush, or the like may be used.

  As a developing method, a general method of developing a magnetic or non-magnetic one-component developer or two-component developer in contact or non-contact is used. It is done. As a transfer method, any of a method using corona discharge, a method using a transfer roller, and the like may be used.

  In addition, as an electrophotographic apparatus, a plurality of constituent elements such as the above-described electrophotographic photosensitive member and development and transfer processes are integrally coupled as an apparatus unit, and this unit can be attached to and detached from the apparatus main body. It may be configured. For example, as shown in FIG. 5, the static elimination exposure unit 32, the charging charger 33, the image exposure unit 35, the proximity of or in contact with the upper surface of the drum-shaped photoreceptor 31 of the present invention, and clockwise along the circumference. An electrophotographic apparatus in which the developing unit 36 and the transfer / separation unit 40 are sequentially attached can be obtained.

  An electrophotographic apparatus equipped with the electrophotographic photosensitive member having the above-described configuration is excellent in resistance to light fatigue and black spots and abnormalities in the wavelength region from the visible region to the near infrared region due to the excellent action of the photosensitive member. A durable image without an image can be obtained.

  Next, the present invention will be described with reference to examples. In addition, the part in an Example represents a weight part and% represents weight%. The electrophotographic photoreceptors obtained in the examples and comparative examples were evaluated according to the following methods.

<Evaluation of light fatigue>
Evaluation of light fatigue was performed using an Imagio MF2730 (manufactured by Ricoh), which is a digital copying machine, and the electrophotographic photosensitive member was left at a position of 1000 lux under a white fluorescent lamp for 60 minutes, and the unexposed portion potential VD ( -V).
ΔVD = VD (initial) −VD (after light irradiation) (Formula I)
The potential was measured as the unexposed portion potential VD (−V) in a state where an electrometer was provided at the development position. The initial VD was adjusted to about −900 V by adjusting the voltage applied to the charging member.

<Image evaluation and potential measurement>
For image evaluation (durability), 50,000 sheets are continuously printed on a chart paper with a black solid part of 5% using a recording paper in an environment of a temperature of 25 ° C./humidity of 50% RH, and 0.1 mm or more in the white part of the recording paper. The number of copies when 1 black spot / square centimeter or more appeared and the presence or absence of occurrence of abnormal images such as a decrease in density other than black spots and background stains were observed. In addition, the unexposed part potential VD (-V) and the exposed part potential VL (-V) were also measured.

Example 1
70 parts of titanium oxide (CR-EL: manufactured by Ishihara Sangyo Co., Ltd.), 15 parts of alkyd resin (Beckolite M6401-50-S (solid content 50%): manufactured by Dainippon Ink & Chemicals, Inc.), melamine resin (Super Becamine L) -121-60 (solid content 60%): Dai Nippon Ink Chemical Co., Ltd. 10 parts and a mixture of methyl ethyl ketone 100 parts were dispersed for 72 hours with a ball mill to prepare an intermediate layer coating solution. This was applied onto an aluminum drum having a diameter of 30 mm and a length of 340 mm, and dried at 130 ° C. for 20 minutes to produce an intermediate layer having a thickness of 3 μm.

  Next, 4.0 parts of an asymmetric disazo pigment represented by the following structural formula (III) and 3.0 parts of X-type metal-free phthalocyanine are 1.4 parts of polyvinyl butyral (ESREC BM-S: manufactured by Sekisui Chemical Co., Ltd.) and 150 parts of cyclohexanone. Was added to the resin solution dissolved in and dispersed for 120 hours in a ball mill. After the completion of dispersion, 210 parts of cyclohexanone was added and dispersed for 3 hours to prepare a charge generation layer coating solution. This was applied onto the intermediate layer and dried at 130 ° C. for 10 minutes to produce a charge generation layer having a thickness of 0.20 μm.

  Next, 7.5 parts of a charge transport material represented by the following structural formula (IV), 10 parts of polycarbonate (Z type: viscosity average molecular weight 40,000), C.I. I. Disperse Orange 5 (λmax = 460 nm) 0.02 part by weight and 0.002 part of silicone oil (KF-50: manufactured by Shin-Etsu Chemical Co., Ltd.) were dissolved in 100 parts of tetrahydrofuran to prepare a charge transport layer coating solution. This was applied onto the charge generation layer and dried at 135 ° C. for 25 minutes to form a charge transport layer having a film thickness of 25 μm. Thus, an electrophotographic photoreceptor of Example 1 was obtained. The electrophotographic photoreceptor was subjected to light fatigue evaluation, image evaluation, and potential measurement according to the above methods. The results are shown in Table 10.

(Example 2)
In Example 1, C.I. I. An electrophotographic photoreceptor of Example 2 was produced in the same manner as in Example 1 except that 0.05 part by weight of dibromoanthanthrone (λmax = 500 nm) was added in place of Disperse Orange 5 in a pulverized state. The electrophotographic photoreceptor was subjected to light fatigue evaluation, image evaluation, and potential measurement according to the above methods. The results are shown in Table 10.

(Example 3)
In Example 1, C.I. I. An electrophotographic photoreceptor of Example 2 was produced in the same manner as in Example 1 except that 5,8-dihydroxy-1,4-naphthoquinone was used instead of Disperse Orange 5. The electrophotographic photoreceptor was subjected to light fatigue evaluation, image evaluation, and potential measurement according to the above methods. The results are shown in Table 10.

Example 4
In Example 1, C.I. I. An electrophotographic photoreceptor of Example 4 was produced in the same manner as in Example 1 except that 1,4-dihydroxy-anthraquinone was used instead of Disperse Orange 5. The electrophotographic photoreceptor was subjected to light fatigue evaluation, image evaluation, and potential measurement according to the above methods. The results are shown in Table 10.

(Example 5)
In Example 1, C.I. I. An electrophotographic photoreceptor of Example 5 was produced in the same manner as in Example 1 except that the compound of Structural Formula (III) was added after dispersion instead of Disperse Orange 5. The electrophotographic photoreceptor was subjected to light fatigue evaluation, image evaluation, and potential measurement according to the above methods. The results are shown in Table 10.

(Comparative Example 1)
In Example 1, C.I. I. An electrophotographic photosensitive member of Comparative Example 1 was produced in the same manner as in Example 1 except that Disperse Orange 5 was not added. The electrophotographic photoreceptor was subjected to light fatigue evaluation, image evaluation, and potential measurement according to the above methods. The results are shown in Table 10.

(Comparative Example 2)
In Example 1, C.I. I. An electrophotographic photoreceptor of Comparative Example 2 was produced in the same manner as in Example 1 except that Sumiplast Yellow C (λmax = 400 nm) was used instead of Disperse Orange 5. The electrophotographic photoreceptor was subjected to light fatigue evaluation, image evaluation, and potential measurement according to the above methods. The results are shown in Table 10.

(Comparative Example 3)
In Example 1, C.I. I. An electrophotographic photosensitive member of Comparative Example 3 was produced in the same manner as in Example 1 except that 2- (2-hydroxy-3,5-dimethylphenyl) benzotriazole, which is an ultraviolet absorber, was used in place of Disperse Orange 5. The electrophotographic photoreceptor was subjected to light fatigue evaluation, image evaluation, and potential measurement according to the above methods. The results are shown in Table 10.

(Example 6)
In Example 1, instead of the asymmetric disazo pigment of the structural formula (III), an asymmetric disazo pigment of the following structural formula (V), an X-type metal-free phthalocyanine pigment which is a phthalocyanine pigment, Further, an electrophotographic photosensitive member of Example 6 was produced in the same manner as in Example 1 except that a charge transport material having the following structural formula (VI) was used instead of the charge transport material having the structural formula (IV). The electrophotographic photoreceptor was subjected to light fatigue evaluation, image evaluation, and potential measurement according to the above methods. The results are shown in Table 11.

(Example 7)
In Example 6, C.I. I. Instead of Disperse Orange 5, C.I. I. An electrophotographic photoreceptor of Example 7 was produced in the same manner as Example 6 except that Disperse Red 116 (λmax = 515 nm) was used. The electrophotographic photoreceptor was subjected to light fatigue evaluation, image evaluation, and potential measurement according to the above methods. The results are shown in Table 11.

(Example 8)
In Example 6, C.I. I. An electrophotographic photoreceptor of Example 8 was produced in the same manner as in Example 6 except that 0.05 part by weight of dibromoanthanthrone (λmax = 500 nm) was added in place of Disperse Orange 5 in a pulverized state. The electrophotographic photoreceptor was subjected to light fatigue evaluation, image evaluation, and potential measurement according to the above methods. The results are shown in Table 11.

Example 9
In Example 6, C.I. I. An electrophotographic photoreceptor of Example 9 was produced in the same manner as in Example 6 except that 5,8-dihydroxy-1,4-naphthoquinone was used instead of Disperse Orange 5. The electrophotographic photoreceptor was subjected to light fatigue evaluation, image evaluation, and potential measurement according to the above methods. The results are shown in Table 11.

(Example 10)
In Example 6, C.I. I. An electrophotographic photoreceptor of Example 10 was produced in the same manner as in Example 6 except that 1,4-dihydroxy-anthraquinone was used instead of Disperse Orange 5. The electrophotographic photoreceptor was subjected to light fatigue evaluation, image evaluation, and potential measurement according to the above methods. The results are shown in Table 11.

(Example 11)
In Example 6, C.I. I. An electrophotographic photosensitive member of Example 11 was produced in the same manner as in Example 6 except that the compound of the structural formula (V) was added after dispersion instead of Disperse Orange 5. The electrophotographic photoreceptor was subjected to light fatigue evaluation, image evaluation, and potential measurement according to the above methods. The results are shown in Table 11.

(Comparative Example 4)
In Example 6, C.I. I. An electrophotographic photosensitive member of Comparative Example 4 was produced in the same manner as in Example 6 except that Disperse Orange 5 was not added. The electrophotographic photoreceptor was subjected to light fatigue evaluation, image evaluation, and potential measurement according to the above methods. The results are shown in Table 11.

(Comparative Example 5)
In Example 6, C.I. I. An electrophotographic photoreceptor of Comparative Example 5 was produced in the same manner as in Example 6 except that Sumiplast Yellow C (λmax = 400 nm) was used instead of Disperse Orange 5. The electrophotographic photoreceptor was subjected to light fatigue evaluation, image evaluation, and potential measurement according to the above methods. The results are shown in Table 11.

(Comparative Example 6)
In Example 6, C.I. I. The electrophotographic photoreceptor of Comparative Example 6 in the same manner as in Example 6 except that 2- (2-hydroxy-3,5-dimethylphenyl) -5-chlorobenzotriazole was used instead of Disperse Orange 5 as an ultraviolet absorber. Was made. The electrophotographic photoreceptor was subjected to light fatigue evaluation, image evaluation, and potential measurement according to the above methods. The results are shown in Table 11.

DESCRIPTION OF SYMBOLS 11 Conductive support body 13 Intermediate | middle layer 17 Charge generation layer 19 Charge transport layer 21 Protective layer 31 Photoconductor 32 Static elimination exposure part 33 Charge charger 35 Image exposure part 36 Development unit 40 Transfer / separation unit

Claims (5)

In an electrophotographic photosensitive member in which at least a charge generation layer and a charge transport layer are laminated on a conductive support, the charge generation layer has two or more types of spectral sensitivity characteristics in different spectral regions of the visible region and the near infrared region. Containing a charge generating substance and a compound having an absorption peak at 450 to 620 nm in the charge transporting layer;
The electrophotographic photoreceptor, wherein the compound having an absorption peak at 450 to 620 nm contained in the charge transport layer is a naphthoquinone or an anthraquinone derivative. 2. The electrophotographic photoreceptor according to claim 1, wherein the charge generating material having spectral sensitivity characteristics in the visible range is an asymmetric disazo pigment represented by the following general formula (I).
(In the formula, A represents a divalent residue bonded to the nitrogen atom of the azo group by a carbon atom. Cp ₁ and Cp ₂ represent coupler residues having different structures.) 3. The electrophotographic photoreceptor according to claim 2, wherein the asymmetric disazo pigment represented by the general formula (I) is a compound represented by the following general formula (II).
(In the formula, Cp ₁ and Cp ₂ represent coupler residues having different structures.)   2. The electrophotographic photosensitive member according to claim 1, wherein the charge generating material having spectral sensitivity characteristics in the near infrared region is a phthalocyanine pigment. The electrophotographic photosensitive member according to any one of claims 1 to 4, wherein at least a charging unit, an exposing unit, a reversal developing unit, and a transfer unit, the electrophotographic photosensitive member mounted on the electrophotographic apparatus is the electrophotographic photosensitive member according to any one of claims 1 to 4. An electrophotographic apparatus characterized by that.