JP2005338446A - Organic photoreceptor, processing cartridge, and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic photoreceptor capable of providing superior potential characteristics and superior electrophotographic images over a long period by simultaneously solving the contradictory characteristics of foreign matter adhesiveness and anti-wear characteristics and preventing the occurrence of dash marks and black spots, and the occurrence of transfer memory, and to provide a processing cartridge which uses the organic photoreceptor and an image forming apparatus. <P>SOLUTION: In the organic photoreceptor, having a charge generating layer containing at least a charge generating substance on a conductive support and a charge transport layer containing a charge transport substance, polycarbonate has a structural unit, in which the charge transport layer is represented by general Formula (1). In addition, the organic photoreceptor contains the charge transport substance represented by general Formula (3). <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an organic photoreceptor (hereinafter also simply referred to as a photoreceptor) used for electrophotographic image formation, a process cartridge, an image forming apparatus, and an image forming method. More specifically, the present invention is used in the fields of copiers and printers. The present invention relates to an organic photoreceptor, a process cartridge, and an image forming apparatus used for electrophotographic image formation.

  In recent years, organic photoreceptors (hereinafter also simply referred to as photoreceptors) have been widely used as electrophotographic photoreceptors. Organic photoreceptors have advantages over other photoreceptors, such as easy development of materials suitable for various exposure light sources from visible light to infrared light, the ability to select materials that are free from environmental pollution, and low manufacturing costs. However, there are disadvantages such as low mechanical strength and easy adhesion of foreign matter, poor chemical durability, deterioration of electrostatic characteristics of a photoreceptor when many sheets are printed, and generation of scratches on the surface.

  That is, the organic photoconductor is a surface generated by a mechanical external force applied when a toner image formed on the photoconductor is transferred to a transfer material such as paper or when residual toner on the photoconductor is cleaned. Durability (abrasion resistance) against foreign matter adhesion and scratches is required.

  That is, the problem that the wear resistance property against contact friction by the cleaning means or the like is insufficient, the surface layer is worn by copying a large number of sheets, and the film thickness is not sufficiently solved yet. That is, as the surface layer is worn, streak-like scratches are generated on the surface of the photoreceptor, and the scratches are reflected in the electrophotographic image, resulting in streaking due to the entire surface of the halftone image, resulting in a rough image. Cheap.

  In addition, the surface of the photoconductor is easily contaminated with paper dust or a toner composition by a developing unit, a transfer unit, a cleaning unit, and the like arranged around the photoconductor, and as a result, a dash mark (small comet-like streak image), Periodic image defects such as transfer defects are likely to occur.

  In order to prevent such wear deterioration of the surface layer, the charge transport layer binder is a polycarbonate resin having high wear resistance, that is, a polycarbonate resin having a central carbon atom in the cyclohexylene group (polycarbonate Z (also simply referred to as BPZ)). And a photoreceptor using a copolymer polycarbonate resin having three types of repeating structural units has been proposed (Patent Documents 1 and 2).

  However, it is difficult to solve the above-described deterioration of the halftone image due to the dash mark or the scratch by the technique of improving the wear resistance of the organic photoreceptor using these binders.

  That is, when the wear resistance is enhanced, the surface layer is more resistant to scratches and abrasion, but contamination of the surface layer is likely to accumulate and a dash mark is likely to occur. On the other hand, if the wear resistance is weak, scratches and wear on the surface layer increase, and halftone image quality is likely to deteriorate.

  Further, as a technique for improving the same wear resistance, a photoreceptor using an ether-bonded polycarbonate resin in which the central carbon atom of bisphenol A is replaced with an oxygen atom has been proposed (Patent Document 3).

  However, the end-group of this ether-bonded polycarbonate resin is likely to be oxidized, so that charge trapping is likely to occur, and a transfer memory is likely to occur along with the generation of the dash mark. In particular, a color image forming apparatus using an intermediate transfer member described later has a problem that a transfer charging history phenomenon, that is, a transfer memory is likely to occur because the photosensitive member is subjected to transfer charging without passing through transfer paper. . Furthermore, this transfer memory problem tends to be easily amplified when a highly sensitive phthalocyanine pigment or the like is used as a charge generation material.

Also disclosed is a technique for improving wear resistance and adhesion of foreign matter to the surface by containing fluororesin fine particles in the surface layer of the organic photoreceptor to reduce the surface energy (Patent Document 4). However, an organic photoreceptor containing fluororesin fine particles tends to cause image blur. In addition, if the surface layer contains fluororesin fine particles in an amount that sufficiently reduces the surface energy, it causes scattering of laser exposure light and deteriorates sharpness, film properties also deteriorate, and mechanical strength easily decreases. Contact friction with the cleaning means or the like causes problems such as scratches on the surface of the photoreceptor, and it is not always possible to provide a good electrophotographic image.
Japanese Patent Application Laid-Open No. 60-172044 JP-A-7-271062 JP-A-6-51544 JP-A-63-65449

  The present invention simultaneously solves the conflicting properties of the organophotoreceptor with respect to foreign matter adhesion and wear resistance, prevents deterioration of halftone images due to dash marks and scratches, and prevents the generation of transfer memory. Another object of the present invention is to provide an organic photoreceptor capable of providing good potential characteristics and a good electrophotographic image in the long term, and to provide a process cartridge and an image forming apparatus using the organic photoreceptor.

In order to solve the above problems, the present inventors have studied the surface layer of the organic photoconductor to prevent deterioration of the dash mark and the halftone image, and at the same time, as a result of continuing the technical development that can prevent the generation of the transfer memory, By using a charge transport material having a specific structure highly compatible with the above-mentioned ether-bonded polycarbonate in the charge transport layer forming the surface layer of the organophotoreceptor, it is possible to prevent deterioration of these dash marks and halftone images, and The present invention has been completed by finding that even when a highly sensitive gallium phthalocyanine pigment is used as a charge generation material, the generation of transfer memory can be improved at the same time. That is, by using a binder resin having an ether bond as the surface layer of the photoreceptor, and forming a charge transport layer that is highly compatible with the binder and can form a dense film, a halftone image caused by a dash mark or an abrasion As a result, the present invention was completed. Further, the organic photoreceptor of the present invention has been found that the effect of the present invention can be exhibited more by providing an intermediate layer containing N-type semiconductive inorganic particles between the conductive support and the photosensitive layer. completed. That is, the object of the present invention can be achieved by having the following configuration.
(Claim 1)
In the organic photoreceptor having a charge generation layer containing at least a charge generation material and a charge transport layer containing a charge transport material on a conductive support, the structural unit represented by the following general formula (1) An organophotoreceptor comprising a polycarbonate having a charge transport material represented by the following general formula (3):

(In General Formula (1), X is an oxygen atom or a sulfur atom, and R _{1 to} R ₈ represent a hydrogen atom, a halogen atom, a hydroxyl group, or an alkyl group having 1 to 4 carbon atoms.)

(In General Formula (3), Ar ₁ and Ar ₂ represent a substituted or unsubstituted aromatic ring group, R ₁ and R ₂ represent a hydrogen atom or an alkyl group, and R ₃ represents a hydrogen atom, an alkyl group, or a halogen atom. Represents an atom.)
(Claim 2)
An organic photoreceptor having a charge generation layer containing at least a charge generation material and a charge transport layer containing a charge transport material on a conductive support, wherein the charge transport layer is a structural unit represented by the general formula (1) An organophotoreceptor comprising a polycarbonate having a charge transport material represented by the following general formula (4):

(In General Formula (4), Ar ₁ and Ar ₂ represent a substituted or unsubstituted aromatic ring group, R ₄ represents a hydrogen atom, an alkyl group, or a halogen atom, and X represents a vinylene group or an ethylene group. )
(Claim 3)
An organic photoreceptor having a charge generation layer containing at least a charge generation material and a charge transport layer containing a charge transport material on a conductive support, wherein the charge transport layer is a structural unit represented by the general formula (1) An organophotoreceptor comprising: a polycarbonate having a charge transport material represented by the following general formula (5):

(In the general formula (5), R ₁ and R ₁ ′ each represent a hydrogen atom, an alkyl group, an alkoxy group or a halogen atom, and R ₂ , R ₂ ′, R ₃ and R ₃ ′ each represent a hydrogen atom, Represents an alkyl group, an alkoxy group, a halogen atom or a substituted amino group, and m, m ′, n and n ′ each represent an integer of 1 or 2.)
(Claim 4)
An organic photoreceptor having a charge generation layer containing at least a charge generation material and a charge transport layer containing a charge transport material on a conductive support, wherein the charge transport layer is a structural unit represented by the general formula (1) An organophotoreceptor comprising a polycarbonate having a charge transport material represented by the following general formula (6):

(In the general formula (6), R ₄ represents a hydrogen atom or a methyl group, and Ar ₁ and Ar ₂ are each an aryl group optionally having a halogen atom, an alkyl group, an alkoxy group or a substituted amino group, or Represents a thienyl group, and k represents an integer of 1 or 2.)
(Claim 5)
The organophotoreceptor according to any one of claims 1 to 4, wherein a gallium phthalocyanine pigment is used as the charge generation material of the charge generation layer.
(Claim 6)
The gallium phthalocyanine pigment has a position of at least 7.4 °, 16.6 °, 25.5 °, 28.3 ° in the Bragg angle (2θ ± 0.2 °) of the characteristic X-ray diffraction spectrum of Cu-Kα. 6. The organophotoreceptor according to claim 5, wherein the organophotoreceptor is a chlorogallium phthalocyanine pigment having a characteristic diffraction peak.
(Claim 7)
The gallium phthalocyanine pigment is at least 7.5 °, 9.9 °, 12.5 °, 16.3 °, 18 in the Bragg angle (2θ ± 0.2 °) of the characteristic X-ray diffraction spectrum of Cu-Kα. 6. The organophotoreceptor according to claim 5, wherein the organophotoreceptor is a hydroxygallium phthalocyanine pigment having diffraction peaks characteristic at positions of 6 °, 25.1 °, and 28.1 °.
(Claim 8)
The gallium phthalocyanine pigment is at least 6.8 °, 12.8 °, 15.8 °, 26.6 ° in the Bragg angle (2θ ± 0.2 °) of the characteristic X-ray diffraction spectrum of Cu-Kα. 6. The organophotoreceptor according to claim 5, wherein the organophotoreceptor is a gallium phthalocyanine pigment having a characteristic diffraction peak.
(Claim 9)
The organic photoreceptor according to claim 1, wherein the charge transport layer contains an antioxidant.
(Claim 10)
The organophotoreceptor according to claim 1, further comprising an intermediate layer containing N-type semiconductive particles between the conductive support and the charge generation layer.
(Claim 11)
The organophotoreceptor according to claim 10, wherein the N-type semiconductor particles are a metal oxide.
(Claim 12)
The organophotoreceptor according to claim 10 or 11, wherein the N-type semiconductor particles are titanium oxide or zinc oxide.
(Claim 13)
The organophotoreceptor according to claim 12, wherein the N-type semiconductor particles are titanium oxide.
(Claim 14)
The organophotoreceptor according to claim 13, wherein the titanium oxide is a rutile titanium oxide pigment or an anatase titanium oxide pigment.
(Claim 15)
The organophotoreceptor according to claim 10, wherein the N-type semiconductor particles are subjected to a surface treatment.
(Claim 16)
The organic photoreceptor according to claim 10, wherein the intermediate layer contains a binder of polyamide resin.
(Claim 17)
The organophotoreceptor according to claim 16, wherein the polyamide resin is a polyamide resin having a heat of fusion of 0 to 40 J / g and a water absorption of 5% by mass or less.
(Claim 18)
18. The organic photoreceptor according to claim 16, wherein a volume ratio of the binder resin and the N-type semiconductor particles in the intermediate layer is N-type semiconductor particles 1 to 2 with respect to the binder resin 1.
(Claim 19)
The organic photoreceptor according to claim 10, wherein the intermediate layer has a thickness of 1 to 10 μm.
(Claim 20)
In a process cartridge used in an image forming apparatus having a charging means for charging by bringing a charging member into contact with an organic photoreceptor, a charge generating layer containing at least a charge generating material and a charge transporting material are contained on a conductive support. At least one of a polycarbonate having a charge transport layer, wherein the charge transport layer has a structural unit represented by the general formula (1), and the charge transport materials represented by the general formulas (3) to (6). An organic photoreceptor containing any one of them, a charging means for charging by bringing a charging member into contact with the organic photoreceptor, a developing means for developing an electrostatic latent image on the organic photoreceptor, and the organic photoreceptor A process cart characterized in that at least one transfer means for transferring a toner image visualized thereon onto a transfer material is integrally supported and is detachably attached to the image forming apparatus main body. Tsu di.
(Claim 21)
In an image forming apparatus having charging means for charging by bringing a charging member into contact with an organic photoreceptor, the organic photoreceptor contains at least a charge generation layer containing a charge generation material and a charge transport material on a conductive support. At least one of a polycarbonate having a charge transport layer, wherein the charge transport layer has a structural unit represented by the general formula (1), and the charge transport materials represented by the general formulas (3) to (6). Any one type is contained, The image forming apparatus characterized by the above-mentioned.

  By using the present invention, it is possible to provide an organic photoreceptor capable of simultaneously improving deterioration of a dash mark or a halftone image and generation of a transfer memory, and capable of producing a good electrophotographic image. A process cartridge, an image forming apparatus, and an image forming method.

  Hereinafter, the present invention will be described in detail.

  The organic photoreceptor of the present invention includes an organic photoreceptor having a charge generation layer containing at least a charge generation material and a charge transport layer containing a charge transport material on a conductive support, wherein the charge transport layer is represented by the general formula ( It comprises a polycarbonate having a structural unit represented by 1) and a charge transport material represented by the general formula (3).

  The organic photoreceptor of the present invention is an organic photoreceptor having a charge generation layer containing at least a charge generation material and a charge transport layer containing a charge transport material on a conductive support. It contains a polycarbonate having a structural unit represented by the formula (1) and a charge transport material represented by the general formula (4).

  The organic photoreceptor of the present invention has the above-described configuration, thereby preventing the dash mark and the halftone image from being deteriorated, preventing the generation of a transfer memory, and providing a good electrophotographic image for a long period.

  Hereinafter, the structure of the organic photoreceptor of the present invention will be described.

  The charge transport layer of the organic photoreceptor of the present invention is characterized by containing a polycarbonate having a structural unit represented by the general formula (1).

  The polycarbonate having the structural unit represented by the general formula (1) may be a polycarbonate having the same chemical structure as the repeating unit structure, but more preferably, the above general formula (1) and the following general formula (2). A copolymer polycarbonate having a structural unit is more preferred.

(In the formula, A represents a linear, branched or cyclic alkylidene group, aryl-substituted alkylidene group and arylene group having 1 to 10 carbon atoms, and R _{9 to} R ₁₆ represent a hydrogen atom, a halogen atom, a hydroxyl group or a carbon atom. Represents an alkyl group of formulas 1 to 4.)
Hereinafter, polycarbonates preferably used in the present invention are exemplified, but the present invention is not limited to polycarbonates having these exemplified structures.

  Among the copolymer polycarbonates having the structural units of the general formula (1) and the general formula (2), a copolymer polycarbonate containing 30 to 70 mol% of the structural unit of the general formula (1) in the entire structure is preferable. More preferred is a copolymer polycarbonate containing 50 to 70 mol%.

  The polycarbonate resin used in the present invention can be obtained by a general polycarbonate synthesis method such as a phosgene method using a diol compound having each structural unit.

  The molecular weight of the polycarbonate of the present invention is preferably a viscosity average molecular weight (Mv) in the range of 10,000 to 150,000, particularly 15 in consideration of the dash mark resistance and abrasion resistance. , Preferably in the range of 100,000 to 100,000.

  The ratio of the binder resin in the charge transport layer is 20 to 80% by mass, preferably 30 to 60% by mass. In the charge transport layer, in addition to the above polycarbonate copolymer, for example, polystyrene, acrylic resin, methacrylic resin, vinyl chloride resin, vinyl acetate resin, polyvinyl butyral resin, epoxy resin, polyurethane resin, phenol resin, polyester resin, alkyd resin, polycarbonate A resin, a silicone resin, a melamine resin, and a copolymer resin containing two or more of the repeating unit structures of these resins may be used in combination.

  The charge transport layer of the present invention is characterized in that the compound represented by the general formula (3) is used as a carrier transport material as a charge transport material.

  In the charge transport layer of the present invention, the compound represented by the general formula (4) is used as a carrier transport material as a charge transport material.

  In the charge transport layer of the present invention, the compound represented by the general formula (5) is used as a charge transport material as a carrier transport material.

  In the charge transport layer of the present invention, the compound represented by the general formula (6) is used as a carrier transport material as a charge transport material.

  The charge transport materials of the general formula (3), general formula (4), general formula (5) and general formula (6) have good compatibility with the polycarbonate having the structural unit of the general formula (1). By using these charge transport materials in combination with polycarbonate, a uniform charge transport layer that does not have microscopic phase separation and is difficult to adhere to foreign matter is formed, and deterioration of halftone images due to dash marks and scratches is prevented, and transfer is also possible. It is possible to have a stable potential characteristic that hardly causes memory. Further, the charge transport materials of the general formula (3) and the general formula (4) are preferably used in combination to improve the compatibility with the polycarbonate having the structural unit of the general formula (1). Similarly, the charge transport materials of the general formula (5) and the general formula (6) are preferably used in combination to improve compatibility with the polycarbonate having the structural unit of the general formula (1).

  Specific examples of the compound of the general formula (3) are listed below, but the present invention is not limited to the specific examples.

  Specific examples of the compound of the general formula (4) are listed below, but the present invention is not limited to the specific examples.

  Specific examples of the compound of the general formula (5) are listed below, but the present invention is not limited to the specific examples.

  Specific examples of the compound of the general formula (6) are listed below, but the present invention is not limited to the specific examples.

  The mass ratio of the binder resin using the polycarbonate in the charge transport layer and the charge transport material is preferably 30 to 200 parts by mass, more preferably 50 to 150 parts by mass with respect to 100 parts by mass of the binder.

  The charge transport layer preferably contains an antioxidant. Typical examples of the antioxidants prevent or suppress oxidation of auto-oxidizing substances existing in or on the surface of an organic photoreceptor under conditions such as light, heat, and discharge. It is a substance with the property to do.

  The antioxidant of the present invention is a substance having the property of preventing or suppressing the action of oxygen under conditions of light, heat, discharge, etc., against an auto-oxidizing substance present in the photoreceptor or on the photoreceptor surface. It is. Specifically, the following compound groups can be mentioned.

(1) Radical chain inhibitor ・ Phenol antioxidant (hindered phenol)
・ Amine antioxidants (hindered amines, diallyldiamines, diallylamines)
・ Hydroquinone antioxidant (2) Peroxide decomposer ・ Sulfur antioxidant (thioethers)
・ Phosphoric antioxidants (phosphites)
Among the above antioxidants, the radical chain inhibitor (1) is good, and a hindered phenol-based or hindered amine-based antioxidant is particularly preferable. Two or more types may be used in combination, for example, a combination of (1) a hindered phenol antioxidant and (2) a thioether antioxidant. Furthermore, the above-mentioned structural unit, for example, a hindered phenol structural unit and a hindered amine structural unit may be included in the molecule.

  Among the antioxidants, hindered phenol-based and hindered amine-based antioxidants are particularly effective in preventing fogging and image blurring at high temperatures and high humidity.

  The content of the hindered phenol-based or hindered amine-based antioxidant in the surface layer is preferably 0.01 to 20% by mass. When the content is less than 0.01% by mass, spots tend to occur. When the content exceeds 20% by mass, the charge transport ability in the surface layer decreases, the residual potential tends to increase, and the film strength decreases. Scratches are likely to occur.

  Here, hindered phenol refers to compounds having a branched alkyl group at the ortho position relative to the hydroxyl group of the phenol compound and derivatives thereof (however, the hydroxyl group may be converted to alkoxy).

  The hindered amine system is a compound having a bulky organic group near the N atom. The bulky organic group includes a branched alkyl group, for example, a t-butyl group is preferable. For example, compounds having an organic group represented by the following structural formula are preferred.

In the formula, R ₁₃ represents a hydrogen atom or a monovalent organic group, R ₁₄ , R ₁₅ , R ₁₆ and R ₁₇ represent an alkyl group, and R ₁₈ represents a hydrogen atom, a hydroxyl group or a monovalent organic group.

  Examples of the antioxidant having a hindered phenol partial structure include compounds described in JP-A-1-118137 (P7 to P14), but the present invention is not limited thereto.

  Examples of the antioxidant having a hindered amine partial structure include compounds described in JP-A-1-118138 (P7 to P9), but the present invention is not limited thereto.

  As an organic phosphorus compound, there exist the following as a typical thing with the compound represented by general formula: RO-P (OR) -OR, for example. Here, R represents a hydrogen atom, each substituted or unsubstituted alkyl group, alkenyl group or aryl group.

  As an organic sulfur type compound, there exist the following as a typical thing with the compound represented by general formula: R-S-R, for example. Here, R represents a hydrogen atom, each substituted or unsubstituted alkyl group, alkenyl group or aryl group.

  The following are examples of typical antioxidant compounds.

  Further, as the antioxidants that have been commercialized, the following compounds, for example, “Irganox 1076”, “Irganox 1010”, “Irganox 1098”, “Irganox 245”, “Irganox 245” as hindered phenols, are used. Knox 1330 "," Irganox 3114 "," Irganox 1076 "," 3,5-di-t-butyl-4-hydroxybiphenyl ", hindered amine series" Sanol LS2626 "," Sanol LS765 "," Sanol LS770 " , “Sanol LS744”, “Tinuvin 144”, “Tinuvin 622LD”, “Mark LA57”, “Mark LA67”, “Mark LA62”, “Mark LA68”, “Mark LA63”, and “Sumilyzer TPS” "," Sumi Iser TP-D ", and the phosphite system is" Mark 2112 "," Mark PEP-8 "," Mark PEP-24G "," Mark PEP-36 "," Mark 329K "," Mark HP-10 " Is mentioned.

  The thickness of the charge transport layer is preferably 10 to 40 μm. If the film thickness is less than 10 μm, deterioration of the halftone image tends to appear, and if it exceeds 40 μm, the residual power rises easily and sharpness tends to deteriorate.

  Further, the charge transport layer may be composed of two layers, and the polycarbonate of the present invention may be used for the charge transport layer serving as the surface layer.

  In the charge generation layer of the present invention, a gallium phthalocyanine pigment is preferably used as a charge generation material. Gallium phthalocyanine pigments have high sensitivity when used in organic photoreceptors, but transfer memories are likely to occur as described above. In the present invention, the problem of such a high-sensitivity gallium phthalocyanine pigment can be solved by the combination with the charge transport layer described above. That is, when a charge generation layer using a high-sensitivity gallium phthalocyanine pigment and a charge transport layer containing the polycarbonate and the charge transport material of the general formula (3) or the general formula (4) are laminated, the charge generation layer and the charge transport layer It is considered that the charge transfer barrier at the interface becomes smaller, and the charge accumulation of transfer charge becomes smaller.

  As the gallium phthalocyanine pigment preferably used in the present invention, at a Bragg angle (2θ ± 0.2 °) of the characteristic X-ray diffraction spectrum of Cu—Kα, at least 7.4 °, 16.6 °, 25.5 °, Chlorgallium phthalocyanine pigment having a characteristic diffraction peak at a position of 28.3 °, at least 7.5 °, 9.9 °, 12.5 °, 16.3 °, 18.6 °, 25.1 °, Hydroxygallium phthalocyanine pigment having a characteristic diffraction peak at 28.1 ° and gallium having characteristic diffraction peaks at least at 6.8 °, 12.8 °, 15.8 °, 26.6 ° Phthalocyanine pigments are preferred. By combining the charge generation layer containing the gallium phthalocyanine pigment having such an X-ray diffraction spectrum and the charge transport layer of the present invention, it is highly sensitive and improves halftone image degradation or transfer memory due to dash marks or scratches. In addition, a good electrophotographic image can be provided.

  Next, the layer structure of the organic photoreceptor having the above surface layer will be described.

  The organic photoconductor of the present invention means an electrophotographic photoconductor constituted by giving an organic compound at least one of a charge generation function and a charge transport function indispensable for the constitution of the electrophotographic photoconductor. It contains all known organic electrophotographic photoreceptors such as a photoreceptor composed of an organic charge generating material or an organic charge transport material, a photoreceptor composed of a polymer complex with a charge generating function and a charge transport function.

  The constitution of the organic photoreceptor used in the present invention is described below.

Conductive Support The conductive support used for the photoreceptor may be either a sheet or a cylinder, but a cylindrical conductive support is preferred for designing an image forming apparatus compactly. .

  Cylindrical conductive support means a cylindrical support necessary for forming an endless image by rotating. Conductivity is within a range of 0.1 mm or less in straightness and 0.1 mm or less in deflection. A support is preferred. Exceeding the range of straightness and shake makes it difficult to form a good image.

As the conductive material, a metal drum such as aluminum or nickel, a plastic drum deposited with aluminum, tin oxide, indium oxide or the like, or a paper / plastic drum coated with a conductive substance can be used. The conductive support preferably has a specific resistance of 10 ³ Ωcm or less at room temperature. The conductive support of the present invention is most preferably an aluminum support. As the aluminum support, one in which components such as manganese, zinc, magnesium and the like are mixed in addition to the main component aluminum is also used.

Intermediate layer In the present invention, an intermediate layer is preferably provided between the conductive support and the photosensitive layer.

  The intermediate layer used in the present invention preferably contains N-type semiconductor particles. The N-type semiconductive particle means a particle whose main charge carrier is an electron. That is, since the main charge carriers are electrons, the intermediate layer containing the N-type semiconductive particles in the insulating binder effectively blocks hole injection from the substrate, and the electrons from the photosensitive layer. In contrast, it has a property of low blocking.

  Here, a method for discriminating N-type semiconductor particles will be described.

  An intermediate layer having a thickness of 5 μm is formed on the conductive support (the intermediate layer is formed using a dispersion in which 50% by mass of particles are dispersed in the binder resin constituting the intermediate layer). The intermediate layer is negatively charged and the light attenuation characteristics are evaluated. In addition, the light attenuation characteristics are similarly evaluated by charging to positive polarity.

  N-type semiconductive particles are particles that are dispersed in the intermediate layer in the above evaluation when the light attenuation when charged negatively is greater than the light attenuation when charged positively. It is called semiconductive particle.

As the N-type semiconductor particles, titanium oxide (TiO ₂ ) and zinc oxide (ZnO) are preferable, and titanium oxide is particularly preferably used.

  As the N-type semiconductor particles, fine particles having a number average primary particle diameter in the range of 3.0 to 200 nm are used. Particularly, 5 nm to 100 nm is preferable. The number average primary particle diameter is a measured value as the average diameter in the ferret direction by image analysis by magnifying fine particles 10,000 times by transmission electron microscope observation, randomly observing 100 particles as primary particles. N-type semiconducting particles having a number average primary particle size of less than 3.0 nm are difficult to uniformly disperse in the intermediate layer binder and easily form agglomerated particles. Likely to happen. On the other hand, N-type semiconducting particles having a number average primary particle size of greater than 200 nm tend to make large irregularities on the surface of the intermediate layer, and halftone images are likely to deteriorate through these large irregularities. Further, N-type semiconducting particles having a number average primary particle size of more than 200 nm are likely to precipitate in the dispersion and easily generate agglomerates, which also increases the deterioration of the halftone image.

  The titanium oxide particles have anatase, rutile, brookite, and amorphous forms as crystal forms. Among them, the rutile form titanium oxide pigment or the anatase form titanium oxide pigment has a rectifying property of charge passing through the intermediate layer. That is, the electron mobility is increased, the charging potential is stabilized, the residual potential is prevented from increasing, and the generation of the transfer memory can be prevented. .

  N-type semiconductive particles are preferably surface-treated with a polymer containing methylhydrogensiloxane units. The molecular weight of the polymer containing the methyl hydrogen siloxane unit is 1000 to 20000, and the surface treatment effect is high. As a result, the rectifying property of the N-type semiconductor particles is improved, and the N-type semiconductor particles are contained. By using the intermediate layer, the occurrence of black spots is prevented and there is an effect in producing a good halftone image.

The polymer containing a methylhydrogensiloxane unit is preferably a copolymer of a structural unit of-(HSi (CH ₃ ) O)-and a structural unit other than this (other siloxane unit). As other siloxane units, dimethylsiloxane units, methylethylsiloxane units, methylphenylsiloxane units, diethylsiloxane units, and the like are preferable, and dimethylsiloxane is particularly preferable. The proportion of methylhydrogensiloxane units in the copolymer is 10 to 99 mol%, preferably 20 to 90 mol%.

  The methylhydrogensiloxane copolymer may be any of a random copolymer, a block copolymer, a graft copolymer, etc., but a random copolymer and a block copolymer are preferred. In addition to methylhydrogensiloxane, the copolymerization component may be one component or two or more components.

  Further, the N-type semiconductive particles may be those surface-treated with a reactive organosilicon compound represented by the following formula.

(R) _n -Si- (X) _4-n
(In the above formula, Si represents a silicon atom, R represents an organic group in which carbon is directly bonded to the silicon atom, X represents a hydrolyzable group, and n represents an integer of 0 to 3).
In the organosilicon compound represented by the above formula, the organic group in which carbon is directly bonded to the silicon represented by R includes alkyl groups such as methyl, ethyl, propyl, butyl, pentyl, hexyl, octyl and dodecyl, phenyl , Aryl groups such as tolyl, naphthyl and biphenyl, epoxy-containing groups such as γ-glycidoxypropyl and β- (3,4-epoxycyclohexyl) ethyl, γ-acryloxypropyl and γ-methacryloxypropyl ( (Meth) acryloyl group, hydroxyl group such as γ-hydroxypropyl, 2,3-dihydroxypropyloxypropyl, vinyl group such as vinyl and propenyl, mercapto group such as γ-mercaptopropyl, γ-aminopropyl, N-β Amino-containing groups such as (aminoethyl) -γ-aminopropyl, γ-chloropropyl, 1,1, - trifluoride Oro propyl, nonafluorohexyl, halogen-containing groups such as perfluorooctylethyl, other nitro, and cyano-substituted alkyl group. Examples of the hydrolyzable group for X include alkoxy groups such as methoxy and ethoxy, halogen groups, and acyloxy groups.

  Moreover, the organosilicon compound represented by the above formula may be used alone or in combination of two or more.

  Further, in the case of a specific compound of an organosilicon compound represented by the above formula and n is 2 or more, a plurality of R may be the same or different. Similarly, when n is 2 or less, the plurality of Xs may be the same or different. Moreover, when using 2 or more types of organosilicon compounds represented by the above formula, R and X may be the same or different between the respective compounds.

  Further, prior to the surface treatment of the methylhydrogensiloxane copolymer or the reactive organosilicon compound, the N-type semiconductive particles may be subjected to an inorganic surface treatment such as alumina or silica.

  In addition, although the above-mentioned treatment of alumina and silica may be performed simultaneously, it is preferable to perform the alumina treatment first and then the silica treatment. Further, the amount of treatment of alumina and silica when treating alumina and silica is preferably higher than that of alumina.

  The surface treatment of the N-type semiconductive fine particles such as titanium oxide with a metal oxide such as alumina, silica or zirconia can be performed by a wet method. For example, N-type semiconductive particles subjected to silica or alumina surface treatment can be prepared as follows.

  When titanium oxide particles are used as the N-type semiconductive particles, titanium oxide particles (number average primary particle size: 50 nm) are dispersed in water at a concentration of 50 to 350 g / L to form an aqueous slurry. Add acid salt or water-soluble aluminum compound. Thereafter, alkali or acid is added for neutralization, and silica or alumina is precipitated on the surface of the titanium oxide particles. Subsequently, filtration, washing, and drying are performed to obtain the target surface-treated titanium oxide. When sodium silicate is used as the water-soluble silicate, it can be neutralized with an acid such as sulfuric acid, nitric acid or hydrochloric acid. On the other hand, when aluminum sulfate is used as the water-soluble aluminum compound, it can be neutralized with an alkali such as sodium hydroxide or potassium hydroxide.

  The intermediate layer coating solution prepared for forming the intermediate layer used in the present invention is composed of a binder resin, a dispersion solvent and the like in addition to the N-type semiconductive particles such as the surface-treated titanium oxide.

  The ratio of the N-type semiconductive particles in the intermediate layer is preferably 1.0 to 2.0 times in terms of the volume ratio of the intermediate layer to the binder resin (when the volume of the binder resin is 1). By using the N-type semiconducting particles of the present invention at such a high density in the intermediate layer, the rectifying property of the intermediate layer is increased, and no increase in residual potential or transfer memory occurs even when the film thickness is increased. Therefore, it is possible to effectively prevent black spots and to form a good organic photoreceptor with a small potential fluctuation. Further, such an intermediate layer preferably uses 100 to 200 parts by volume of N-type semiconductive particles with respect to 100 parts by volume of the binder resin.

  On the other hand, the binder resin in which these particles are dispersed to form the layer structure of the intermediate layer is preferably a polyamide resin in order to obtain good dispersibility of the particles, but the polyamide resin shown below is particularly preferable.

  That is, a polyamide resin having a heat of fusion of 0 to 40 J / g and a water absorption of 5% by mass or less is preferable for the intermediate layer. The heat of fusion is more preferably 0 to 30 J / g, and most preferably 0 to 20 J / g. On the other hand, when the water absorption exceeds 5% by mass, the moisture content in the intermediate layer increases, the rectification property of the intermediate layer decreases, black spots tend to occur, and the halftone image tends to deteriorate. The water absorption is more preferably 4% by mass or less.

  The heat of fusion of the resin is measured by DSC (Differential Scanning Calorimetry). However, if the same measurement value as the DSC measurement value is obtained, the DSC measurement method is not particular. The heat of fusion is determined from the endothermic peak area when the DSC temperature rises.

  On the other hand, the water absorption rate of the resin is determined by mass change by the water immersion method or by the Karl Fischer method.

The binder resin for the intermediate layer is preferably an alcohol-soluble polyamide resin. As the binder resin for the intermediate layer of the organic photoreceptor, a resin having excellent solvent solubility is required in order to form the intermediate layer with a uniform film thickness. As such an alcohol-soluble polyamide resin, a copolymerized polyamide resin or a methoxymethylated polyamide resin composed of a chemical structure with few carbon chains between amide bonds such as 6-nylon described above is known. This resin has a high water absorption rate, and the intermediate layer using such a polyamide tends to be highly environment-dependent. As a result, for example, charging characteristics and sensitivity under high temperature and high humidity and low temperature and low humidity are likely to change.
Black spots are likely to occur and halftone images are likely to deteriorate.

  Alcohol-soluble polyamide resin improves the above-mentioned drawbacks and improves the disadvantages of conventional alcohol-soluble polyamide resins by giving the characteristics of heat of fusion 0-40 J / g and water absorption of 5% by mass or less. Even if the external environment changes or even if the organic photoreceptor is used continuously for a long time, a good electrophotographic image can be obtained.

  Hereinafter, the alcohol-soluble polyamide resin having a heat of fusion of 0 to 40 J / g and a water absorption of 5% by mass or less will be described.

  The alcohol-soluble polyamide resin is preferably a polyamide resin containing a repeating unit structure having 7 to 30 carbon atoms between amide bonds in an amount of 40 to 100 mol% of the entire repeating unit structure.

  Here, a repeating unit structure having 7 to 30 carbon atoms between amide bonds will be described. The repeating unit structure means an amide bond unit forming a polyamide resin. This is because a polyamide resin (type A) formed by condensation of a compound having a repeating unit structure having both an amino group and a carboxylic acid group, and a polyamide resin (type B) formed by condensation of a diamino compound and a dicarboxylic acid compound. ) In both examples.

  That is, the repeating unit structure of type A is represented by the general formula (7), and the carbon number contained in X is the carbon number of the amide bond unit in the repeating unit structure. On the other hand, the type B repeating unit structure is represented by the general formula (8), and the number of carbon atoms contained in Y and the number of carbon atoms contained in Z are the carbon number of the amide bond unit in the repeating unit structure.

In general formula (7), R ₁ is a hydrogen atom, a substituted or unsubstituted alkyl group, X is a substituted or unsubstituted alkylene group, a group containing a divalent cycloalkane, a divalent aromatic group, and these A mixed structure is shown, and l is a natural number.

In general formula (8), R ₂ and R ₃ are each hydrogen atom, a substituted or unsubstituted alkyl group, Y and Z are each substituted or unsubstituted alkylene group, a group containing a divalent cycloalkane, divalent And m and n are natural numbers.

  As described above, the repeating unit structure having 7 to 30 carbon atoms includes a substituted or unsubstituted alkylene group, a group containing a divalent cycloalkane, a divalent aromatic group, and a chemical structure having a mixed structure thereof. Among them, a chemical structure having a group containing a divalent cycloalkane is preferable.

  The polyamide resin has 7 to 30 carbon atoms between amide bonds in the repeating unit structure, preferably 9 to 25, more preferably 11 to 20. The proportion of the repeating unit structure having 7 to 30 carbon atoms between amide bonds in the entire repeating unit structure is 40 to 100 mol%, preferably 60 to 100 mol%, more preferably 80 to 100 mol%.

  When the carbon number is less than 7, the hygroscopicity of the polyamide resin is large, the electrophotographic characteristics, particularly the humidity dependency of the potential during repeated use is large, and image defects such as black spots are likely to occur, and the halftone image is Easy to deteriorate. If it is larger than 30, the dissolution of the polyamide resin in the coating solvent becomes worse, and it is not suitable for forming a coating film of the intermediate layer.

  Further, when the ratio of the repeating unit structure having 7 to 30 carbon atoms between amide bonds to the entire repeating unit structure is smaller than 40 mol%, the above effect is reduced.

  A preferable polyamide resin of the present invention includes a polyamide having a repeating unit structure represented by the following general formula (9).

In General Formula (9), Y ₁ represents a group containing a divalent alkyl-substituted cycloalkane, Z ₁ represents a methylene group, m represents 1 to 3, and n represents 3 to 20.

In the general formula (9), the group containing a divalent alkyl-substituted cycloalkane of Y ₁ preferably has the following chemical structure. That is, the polyamide resin of the present invention in which Y ₁ has the following chemical structure has a remarkable effect of preventing deterioration of black spots and halftone images.

In the above chemical structure, A represents a single bond and an alkylene group having 1 to 4 carbon atoms, R ₄ represents a substituent, represents an alkyl group, and p represents a natural number of 1 to 5. However, the plurality of R ₄ may be the same or different.

  Specific examples of the polyamide resin include the following examples.

  In the above specific examples, “%” in parentheses indicates the ratio (mol%) of the repeating unit structure having 7 or more carbon atoms between amide bonds in the repeating unit structure.

  Among the above specific examples, N-1 to N-4 polyamide resins having a repeating unit structure of the general formula (9) are particularly preferable.

  The molecular weight of the polyamide resin is preferably 5,000 to 80,000, more preferably 10,000 to 60,000 in terms of number average molecular weight. When the number average molecular weight is 5,000 or less, the uniformity of the film thickness of the intermediate layer is deteriorated, and the effects of the present invention are not sufficiently exhibited. On the other hand, if it is larger than 80,000, the solvent solubility of the resin tends to be lowered, and an agglomerated resin is likely to be generated in the intermediate layer, so that black spots and halftone images are likely to be deteriorated.

  A part of the polyamide resin is already available on the market. For example, the polyamide resin is sold under the trade names such as Vestamelt X1010 and X4685 manufactured by Daicel Degussa Co., Ltd., and can be produced by a general synthesis method of polyamide. However, an example of a synthesis example is given below.

Synthesis of exemplified polyamide resin (N-1) 215 parts by mass of lauryl lactam, 3-aminomethyl-3,5,5-trimethylcyclohexylamine in a polymerization kettle equipped with a stirrer, nitrogen, nitrogen introduction tube, thermometer, dehydration tube, etc. 112 parts by mass, 153 parts by mass of 1,12-dodecanedicarboxylic acid and 2 parts by mass of water were mixed and reacted for 9 hours while distilling water under heating and pressure. When the polymer was taken out and the copolymer composition was determined by C ¹³ -NMR, it coincided with the composition of N-1. The melt flow index (MFI) of the synthesized copolymer was 5 g / 10 min under the condition of (230 ° C./2.16 kg).

  As the solvent for dissolving the polyamide resin and preparing the coating solution, alcohols having 2 to 4 carbon atoms such as ethanol, n-propyl alcohol, isopropyl alcohol, n-butanol, t-butanol, sec-butanol are preferable, It is excellent in the solubility of polyamide and the coating property of the prepared coating solution. These solvents are 30 to 100% by mass, preferably 40 to 100% by mass, and more preferably 50 to 100% by mass in the total solvent. Examples of co-solvents that can be used in combination with the above-mentioned solvent to obtain preferable effects include methanol, benzyl alcohol, toluene, methylene chloride, cyclohexanone, and tetrahydrofuran.

  The thickness of the intermediate layer of the present invention is preferably 0.3 to 10 μm. If the thickness of the intermediate layer is less than 0.5 μm, black spots and halftone images are likely to be deteriorated. As for the film thickness of an intermediate | middle layer, 0.5-5 micrometers is more preferable.

Moreover, it is preferable that the said intermediate | middle layer is an insulating layer substantially. Here, the insulating layer has a volume resistance of 1 × 10 ⁸ or more. The volume resistance of the intermediate layer and the protective layer of the present invention is preferably 1 × 10 ⁸ to 10 ¹⁵ Ω · cm, more preferably 1 × 10 ⁹ to 10 ¹⁴ Ω · cm, and further preferably 2 × 10 ⁹ to 1 ×. 10 ¹³ Ω · cm. The volume resistance can be measured as follows.

  Measurement conditions: According to JIS: C2318-1975.

Measuring instrument: Hiresta IP manufactured by Mitsubishi Yuka
Measurement conditions: Measurement probe HRS
Applied voltage: 500V
Measurement environment: 30 ± 2 ℃, 80 ± 5RH%
If the volume resistance is less than 1 × 10 ⁸ , the charge blocking property of the intermediate layer decreases, the occurrence of black spots increases, the potential holding property of the organic photoreceptor deteriorates, and good image quality cannot be obtained. On the other hand, if it is greater than 10 ¹⁵ Ω · cm, the residual potential tends to increase in repeated image formation, and good image quality cannot be obtained.

Photosensitive layer The photosensitive layer configuration of the photoreceptor of the present invention may be a single-layer photosensitive layer configuration in which the intermediate layer has a charge generation function and a charge transport function in one layer, but more preferably the function of the photosensitive layer. The charge generation layer (CGL) and the charge transport layer (CTL) may be separated from each other. By adopting a configuration in which the functions are separated, an increase in the residual potential due to repeated use can be controlled to be small, and other electrophotographic characteristics can be easily controlled according to the purpose. In the negatively charged photoconductor, it is preferable that a charge generation layer (CGL) is formed on the intermediate layer, and a charge transport layer (CTL) is formed thereon. In the positively charged photoconductor, the order of the layer configuration is the reverse of that in the negatively charged photoconductor. The most preferred photosensitive layer structure of the present invention is a negatively charged photoreceptor structure having the function separation structure.

  The structure of the photosensitive layer of the function-separated negatively charged photoreceptor will be described below.

Charge generation layer The charge generation layer contains a charge generation material (CGM). Other substances may contain a binder resin and other additives as necessary.

  It is preferable to use the aforementioned gallium phthalocyanine pigment as the charge generation material. In addition to the gallium phthalocyanine pigment, a known charge generating substance (CGM) can be used in combination. For example, phthalocyanine pigments other than gallium phthalocyanine pigments, azo pigments, perylene pigments, azulenium pigments, and the like can be used. However, a gallium phthalocyanine pigment is preferred as the main charge generating substance.

  When a binder is used as the CGM dispersion medium in the charge generation layer, a known resin can be used as the binder, but the most preferred resins include formal resin, butyral resin, silicone resin, silicone-modified butyral resin, phenoxy resin, and the like. Can be mentioned. The ratio of the binder resin to the charge generating material is preferably 20 to 600 parts by mass with respect to 100 parts by mass of the binder resin. By using these resins, the increase in residual potential associated with repeated use can be minimized. The thickness of the charge generation layer is preferably 0.01 μm to 1 μm. If the thickness is less than 0.01 μm, sufficient sensitivity characteristics cannot be obtained, and the residual potential tends to increase. On the other hand, even if the thickness exceeds 1 μm, the sensitivity tends to decrease and a transfer memory tends to occur.

Charge Transport Layer The charge transport layer of the present invention is used as the charge transport layer of the present invention.

  Solvents or dispersion media used to form layers such as intermediate layers, charge generation layers, and charge transport layers include n-butylamine, diethylamine, ethylenediamine, isopropanolamine, triethanolamine, triethylenediamine, N, N-dimethylformamide, acetone , Methyl ethyl ketone, methyl isopropyl ketone, cyclohexanone, benzene, toluene, xylene, chloroform, dichloromethane, 1,2-dichloroethane, 1,2-dichloropropane, 1,1,2-trichloroethane, 1,1,1-trichloroethane, trichloroethylene, Tetrachloroethane, tetrahydrofuran, dioxolane, dioxane, methanol, ethanol, butanol, isopropanol, ethyl acetate, butyl acetate, dimethyl sulfoxide, methyl cello Lube, and the like. Although this invention is not limited to these, Dichloromethane, 1, 2- dichloroethane, methyl ethyl ketone, etc. are used preferably. These solvents may be used alone or as a mixed solvent of two or more.

  The coating solution for each layer is preferably filtered with a metal filter, a membrane filter or the like in order to remove foreign matters and aggregates in the coating solution before entering the coating step. For example, it is preferable to select a pleated type (HDC), a depth type (profile), a semi-depth type (profile star), etc., manufactured by Nippon Pole Co., Ltd. according to the characteristics of the coating solution and perform filtration.

  Next, as a coating processing method for producing the organic photoreceptor, a coating processing method such as dip coating, spray coating, circular amount regulation type coating or the like is used. It is most preferable to use the circular amount regulation type coating method for the protective layer. The circular amount regulation type coating is described in detail in, for example, Japanese Patent Application Laid-Open No. 58-189061.

  Next, an image forming apparatus using the organic photoreceptor of the present invention will be described.

  An image forming apparatus 1 shown in FIG. 1 is a digital image forming apparatus, and includes an image reading unit A, an image processing unit B, an image forming unit C, and a transfer paper transport unit D as a transfer paper transport unit. Yes.

  An automatic document feeder that automatically conveys the document is provided above the image reading unit A. The document placed on the document table 11 is separated and conveyed by the document conveyance roller 12 to the reading position 13a. The image is read. The document after the document reading is completed is discharged onto the document discharge tray 14 by the document transport roller 12.

  On the other hand, the image of the original when placed on the platen glass 13 is read at a speed v of the first mirror unit 15 including the illumination lamp and the first mirror constituting the scanning optical system, and the V-shaped first image is located. Reading is performed by the movement of the second mirror unit 16 including the two mirrors and the third mirror in the same direction at the speed v / 2.

  The read image is formed on the light receiving surface of the image sensor CCD, which is a line sensor, through the projection lens 17. The line-shaped optical image formed on the image sensor CCD is sequentially photoelectrically converted into an electric signal (luminance signal) and then A / D converted, and the image processing unit B performs processing such as density conversion and filter processing. Then, the image data is temporarily stored in the memory.

  In the image forming unit C, as an image forming unit, a drum-shaped photoconductor 21 as an image carrier, a charging means (charging step) 22 for charging the photoconductor 21 on the outer periphery thereof, and a surface potential of the charged photoconductor. Potential detecting means 220 for detecting the color, developing means (development process) 23, transfer / conveying belt device 45 as transfer means (transfer process), cleaning device (cleaning process) 26 for the photosensitive member 21, and photostatic means (photo-site charge). PCLs (precharge lamps) 27 as generating steps) are arranged in the order of operation. Further, on the downstream side of the developing means 23, a reflection density detecting means 222 for measuring the reflection density of the patch image developed on the photosensitive member 21 is provided. The photoconductor 21 uses the organic photoconductor of the present invention and is driven to rotate in the clockwise direction shown in the figure.

  After the rotating photosensitive member 21 is uniformly charged by the charging unit 22, an image based on an image signal called from the memory of the image processing unit B by an exposure optical system as an image exposure unit (image exposure step) 30 is used. Exposure is performed. The exposure optical system as the image exposure means 30 serving as a writing means uses a laser diode (not shown) as a light source, passes through a rotating polygon mirror 31, an fθ lens 34, and a cylindrical lens 35, and the optical path is bent by the reflection mirror 32 to perform main scanning. Therefore, image exposure is performed on the photoconductor 21 at the position Ao, and an electrostatic latent image is formed by rotation (sub-scanning) of the photoconductor 21. In one example of the present embodiment, the character portion is exposed to form an electrostatic latent image.

In the image forming method of the present invention, when an electrostatic latent image is formed on a photoreceptor, it is preferable to perform image exposure using an exposure beam having a spot area of 2 × 10 ⁻⁹ m ² or less. Even when such small-diameter beam exposure is performed, the organic photoreceptor of the present invention can faithfully form an image corresponding to the spot area. A more preferable spot area is 0.01 × 10 ⁻⁹ to 1 × 10 ⁻⁹ m ² . As a result, it is possible to achieve extremely excellent image quality that achieves 256 gradations at 400 dpi (dpi: the number of dots per 2.54 cm) or more.

The spot area of the exposure beam is represented by an area corresponding to a light intensity at which the intensity of the beam light is 1 / e ² or more of the peak intensity.

The exposure beam used includes a scanning optical system using a semiconductor laser, and a solid state scanner such as an LED or a liquid crystal shutter. The light intensity distribution includes a Gaussian distribution and a Lorentz distribution, but 1 / e of each peak intensity. ^The area up to ² is the spot area.

  The electrostatic latent image on the photoconductor 21 is reversely developed by the developing unit 23, and a visible toner image is formed on the surface of the photoconductor 21. In the image forming method of the present invention, either a pulverized toner or a polymerized toner may be used as the developer used in the developing means. However, a polymerized toner having a uniform shape and particle size distribution is used as the organic photoreceptor of the present invention. By using in combination, an electrophotographic image with better sharpness can be obtained.

  The organic photoreceptor of the present invention is effective when the toner containing 0.1 to 1.0 μm of inorganic external additive and 50 nm or less of inorganic external additive is used as a developer. The effect of improving the deterioration of halftone images due to scratches is great.

  In the transfer paper transport section D, paper feed units 41 (A), 41 (B), and 41 (C) are provided below the image forming unit as transfer paper storage means for storing transfer paper P of different sizes. Further, a manual paper feeding unit 42 for manually feeding paper is provided on the side, and the transfer paper P selected from any of them is fed along the transport path 40 by the guide roller 43 and fed. The transfer paper P is temporarily stopped by a pair of paper feed registration rollers 44 that correct the inclination and bias of the transfer paper P to be transferred, and then fed again. The transport path 40, the pre-transfer roller 43a, and the paper feed path 46 The toner image on the photosensitive member 21 is transferred to the transfer paper P while being transferred to the transfer conveyance belt 454 of the transfer conveyance belt device 45 by the transfer electrode 24 and the separation electrode 25 at the transfer position Bo. Is, transfer sheet P is separated from the photosensitive member 21 surface, it is conveyed to the fixing unit 50 by the transfer conveyor belt device 45.

  The fixing unit 50 includes a fixing roller 51 and a pressure roller 52. By passing the transfer paper P between the fixing roller 51 and the pressure roller 52, the toner is fixed by heating and pressing. After the toner image has been fixed, the transfer paper P is discharged onto the paper discharge tray 64.

  The above describes the state in which image formation is performed on one side of the transfer paper. However, in the case of double-sided copying, the paper discharge switching member 170 is switched, the transfer paper guide 177 is opened, and the transfer paper P is indicated by a broken arrow. Conveyed in the direction.

  Further, the transfer paper P is transported downward by the transport mechanism 178 and switched back by the transfer paper reversing unit 179, and the rear end portion of the transfer paper P becomes the leading end portion and transported into the duplex copying paper supply unit 130. The

  The transfer paper P is moved in a paper feed direction by a conveyance guide 131 provided in the double-sided copy paper supply unit 130, the transfer paper P is re-fed by the paper supply roller 132, and the transfer paper P is guided to the conveyance path 40. .

  Again, as described above, the transfer paper P is conveyed in the direction of the photosensitive member 21, the toner image is transferred to the back surface of the transfer paper P, fixed by the fixing unit 50, and then discharged onto the paper discharge tray 64.

  The image forming apparatus of the present invention is configured by integrally combining the above-described photosensitive member and components such as a developing device and a cleaning device as a process cartridge, and this unit is configured to be detachable from the apparatus main body. Also good. In addition, a process cartridge is formed by integrally supporting at least one of a charger, an image exposure device, a developing device, a transfer or separation device, and a cleaning device together with a photosensitive member, and a single unit that is detachable from the apparatus main body. It is good also as a structure which can be attached or detached using guide means, such as a rail of an apparatus main body.

  Next, FIG. 2 shows a color image forming apparatus using the organic photoreceptor of the present invention (a copying machine having at least a charging means, an exposure means, a plurality of developing means, a transfer means, a cleaning means and an intermediate transfer body around the organic photoreceptor. 1 is a sectional view of the configuration of a laser beam printer). The belt-shaped intermediate transfer body 10 uses an elastic body having a medium resistance.

  Reference numeral 21 denotes a rotary drum type photoconductor that is repeatedly used as an image forming body, and is rotated at a predetermined peripheral speed in the counterclockwise direction indicated by an arrow.

  In the rotation process, the photosensitive member 21 is uniformly charged to a predetermined polarity and potential by the charging unit 22, and then modulated by the image exposure unit 30 (not shown) corresponding to the time-series electric digital pixel signal of the image information. An electrostatic latent image corresponding to a yellow (Y) color component image of a target color image is formed by receiving image exposure with scanning exposure light or the like by a laser beam.

  Next, the electrostatic latent image is developed with yellow toner which is the first color by yellow (Y) developing means (yellow color developing device) 23Y. At this time, the second to fourth developing means (magenta developer, cyan developer, black developer) 23M, 23C, and 23Bk are turned off and do not act on the photosensitive member 21. The first color yellow toner image is not affected by the second to fourth developing units.

  The intermediate transfer member 70 is stretched by rollers 79a, 79b, 79c, 79d, and 79e, and is rotationally driven in the clockwise direction at the same peripheral speed as the photosensitive member 21.

  The yellow toner image of the first color formed and supported on the photoreceptor 21 is applied to the intermediate transfer body 70 from the primary transfer roller 24a in the process of passing through the nip portion between the photoreceptor 1 and the intermediate transfer body 70. The intermediate transfer (primary transfer) is sequentially performed on the outer peripheral surface of the intermediate transfer body 70 by the electric field formed by the primary transfer bias.

  The surface of the photoconductor 21 after the transfer of the first color yellow toner image corresponding to the intermediate transfer body 70 is cleaned by the cleaning device 26.

  Similarly, the second color magenta toner image, the third color cyan toner image, and the fourth color black (black) toner image are sequentially superimposed and transferred onto the intermediate transfer body 70 to correspond to the target color image. A superimposed color toner image is formed.

  The secondary transfer roller 24b is supported in parallel with the secondary transfer counter roller 79b so as to be separated from the lower surface of the intermediate transfer body 70.

  The primary transfer bias for sequentially superimposing and transferring the first to fourth color toner images from the photosensitive member 21 to the intermediate transfer member 70 has a polarity opposite to that of the toner and is applied from a bias power source. The applied voltage is, for example, in the range of +100 V to +2 kV.

  In the primary transfer process of the first to third color toner images from the photosensitive member 21 to the intermediate transfer member 70, the secondary transfer roller 24b and the intermediate transfer member cleaning means 26A can be separated from the intermediate transfer member 70. is there.

  When the superimposed color toner image transferred onto the belt-shaped intermediate transfer body 70 is transferred to the transfer material P, which is the second image carrier, the secondary transfer roller 24b is brought into contact with the belt of the intermediate transfer body 70. At the same time, the transfer material P is fed from the pair of paper supply registration rollers 44 through the transfer sheet guide to the belt of the intermediate transfer body 70 to the contact nip with the secondary transfer roller 24b at a predetermined timing. A secondary transfer bias is applied to the secondary transfer roller 24b from a bias power source. By this secondary transfer bias, the superimposed color toner image is transferred (secondary transfer) from the intermediate transfer body 70 to the transfer material P as the second image carrier. The transfer material P that has received the transfer of the toner image is introduced into the fixing means 50 and fixed by heating.

  The organophotoreceptor of the present invention is generally applicable to electrophotographic apparatuses such as electrophotographic copying machines, laser printers, LED printers, and liquid crystal shutter printers, but further displays, recordings, light printing, plate making and facsimiles using electrophotographic technology. The present invention can be widely applied to such devices.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail, the aspect of this invention is not limited to this. However, “part” in the following text indicates “part by mass”.

Example 1 (Example corresponding to claim 1)
A photoreceptor used for evaluation was produced as follows.

Preparation of photoreceptor 1 Intermediate layer 1
The following intermediate layer coating solution was applied by a dip coating method on a washed cylindrical aluminum substrate (processed to 10-point surface roughness Rz: 0.81 μm as defined in JISB-0601 by cutting) at 120 ° C. for 30 minutes. It dried and formed the intermediate | middle layer 1 with a dry film thickness of 1.0 micrometer.

  The following intermediate layer dispersion is diluted twice with the same mixed solvent, and is allowed to stand overnight and then filtered (filter; rigesh mesh filter made by Nippon Pole Co., Ltd., nominal filtration accuracy: 5 microns, pressure: 50 kPa). Produced.

(Preparation of intermediate layer dispersion)
Binder resin: (Exemplary polyamide N-1) 1 part (1.00 volume part)
2. Rutile-type titanium oxide A1 (primary particle size 35 nm; a surface treatment using a copolymer of methylhydrogensiloxane and dimethylsiloxane (molar ratio 1: 1) in an amount of 5% by mass of the total mass of titanium oxide) 5 parts (1.0 part by volume)
Ethanol / n-propyl alcohol / THF (= 45/20/30 mass ratio) 10 parts The above components were mixed and dispersed in a batch system for 10 hours using a sand mill disperser to prepare an intermediate layer dispersion. .

Charge generation layer The following components were mixed and dispersed using a sand mill disperser to prepare a charge generation layer coating solution. This coating solution was applied by a dip coating method to form a charge generation layer having a dry film thickness of 0.3 μm on the intermediate layer.

Hydroxygallium phthalocyanine pigment (at the Bragg angle (2θ ± 0.2 °) of the characteristic X-ray diffraction spectrum of Cu-Kα, at least 7.5 °, 9.9 °, 12.5 °, 16.3 °, 18. Hydroxygallium phthalocyanine pigment having characteristic diffraction peaks at 6 °, 25.1 °, and 28.1 °) 20 parts Silicone-modified polyvinyl butyral 10 parts 4-methoxy-4-methyl-2-pentanone 700 parts t- Butyl acetate 300 parts Charge transport layer The following components were mixed and dissolved to prepare a charge transport layer coating solution. This coating solution was applied onto the charge generation layer by a dip coating method to form a charge transport layer having a dry film thickness of 25 μm.

Charge transport material (Exemplary compound CT3-3) 70 parts Binder resin (Exemplary compound PC-1 (Mv: 30000)) 100 parts Antioxidant (Exemplary compound 1-1) 8 parts Tetrahydrofuran / toluene (volume ratio 8/2) 750 parts Preparation of photoconductors 2 to 15 N-type semiconductive particles of the intermediate layer, binder resin, dry film thickness, charge generation material, binder resin of charge transport layer, charge transport material, film thickness, etc. are as shown in Table 1. Photoconductors 2 to 15 were produced in the same manner as Photoconductor 1 except for the changes. However, the volume ratio of the intermediate layer in Table 1 is the same as the volume of the binder resin and the volume of the binder resin after the total volume of the binder resin in all the intermediate layers of the photoreceptors 1 to 15 and the volume of the N-type semiconductor particles are made constant. An intermediate layer dispersion was prepared by changing the volume ratio (Vn / Vb) of the type semiconductive particles to form an intermediate layer.

At the same time as the production of the photoconductors 1 to 15, each intermediate layer coating solution was applied onto an aluminum-deposited polyethylene terephthalate support using the intermediate layer coating solution of each photoconductor. An intermediate layer having a dry film thickness of 10 μm was formed under the same conditions to prepare a volume resistance measurement sample, and the volume resistance of each intermediate layer was measured. As a result, the volume resistances of the intermediate layers of the photoreceptors 1 to 15 were all 1 × 10 ⁸ Ω · cm or more. The structural formulas of charge transport material CR, binder resin PC-K, PC-Z, etc. in Table 1 are shown below.

In the table,
A1 is rutile titanium oxide A2 is anatase titanium oxide Z is zinc oxide * 1 is a copolymer of methylhydrogensiloxane and dimethylsiloxane (molar ratio 1: 1)
* 2 is a copolymer of methylhydrogensiloxane and dimethylsiloxane (molar ratio 9: 1)
* 3 is a copolymer of methylhydrogensiloxane and dimethylsiloxane (molar ratio 2: 8)
* 4 is a copolymer of methylhydrogensiloxane and diethylsiloxane (molar ratio 1: 1)
* 5: Copolymer of methylhydrogensiloxane and methylethylsiloxane (molar ratio 1: 1)
* 6 is methylhydrogenpolysiloxane * 7 is primary treatment: silica / alumina, secondary treatment methyltrimethoxysilane In the table, surface treatment refers to the substance used for the surface treatment applied to the surface of the particles (however, The silica / alumina of the primary treatment means silica / alumina deposited on the particle surface).

  The heat of fusion and water absorption in the table were measured as follows.

Measurement conditions of heat of fusion Measuring machine: Measured using Shimadzu Corporation “Shimadzu heat flow rate differential scanning calorimeter DSC-50”.

  Measurement conditions: The measurement sample is set in the above-mentioned measuring machine, measurement is started from room temperature (24 ° C.), the temperature is raised to 200 ° C. at 5 ° C./min, and then cooled to room temperature at 5 ° C./min. This is repeated twice, and the heat of fusion is calculated from the endothermic peak area due to melting during the second temperature increase.

Measurement condition of water absorption rate The sample to be measured is sufficiently dried at 70 to 80 ° C. for 3 to 4 hours, and its mass is accurately weighed. Next, the sample is put into ion-exchanged water maintained at 20 ° C., and after a certain period of time, the sample surface is pulled up and wiped off with a clean cloth, and the mass is measured. The above operation was repeated until the increase in mass was saturated, and the value obtained by dividing the increased mass (increase) of the resulting sample by the initial mass was taken as the water absorption rate.

  In the table, the ratio of the unit structure having 7 or more carbon atoms refers to the ratio (mol%) of the repeating unit structure having 7 or more carbon atoms between amide bonds in the repeating unit structure.

  In the table, G1, G2, and G3 represent the following charge generating substances.

G1 is at least 7.5 °, 9.9 °, 12.5 °, 16.3 °, 18.6 ° in the Bragg angle (2θ ± 0.2 °) of the characteristic X-ray diffraction spectrum of Cu—Kα, Hydroxygallium phthalocyanine pigment G2 having characteristic diffraction peaks at positions of 25.1 ° and 28.1 ° G2 is at least 7. in the Bragg angle (2θ ± 0.2 °) of the characteristic X-ray diffraction spectrum of Cu-Kα. Chlorgallium phthalocyanine pigment having characteristic diffraction peaks at positions of 4 °, 16.6 °, 25.5 °, 28.3 ° G3 is a Bragg angle (2θ ± 0. 0.) of the characteristic X-ray diffraction spectrum of Cu-Kα. 2 °) gallium phthalocyanine pigment having characteristic diffraction peaks at positions of at least 6.8 °, 12.8 °, 15.8 °, 26.6 ° << Evaluation >>
The obtained photoreceptor was mounted on a commercially available color printer, magiccolor 2300 Desk Laser (manufactured by Minolta EMS), and an endurance test was conducted at low temperature and low humidity (LL: 10 ° C., 20% RH). Specifically, a total of 20,000 image images in which the character ratio, halftone image, solid white image, and solid black image with a pixel rate of 7% are divided into quarters are printed, and evaluated at the start and every 5000 images. did. Evaluation items and evaluation criteria are shown below.

  The process conditions for the color printer were as follows.

Charger: Sawtooth electrode Exposure device: Semiconductor laser Development: Nonmagnetic polymerized toner having an average particle diameter of 6.5 μm and containing 0.3 μm of strontium titanate and 15 nm of hydrophobic silica, reversal development method Transfer: Use of intermediate transfer belt Cleaning: Cleaning blade Fixing: Heat fixing Process speed: 100mm / sec
Image density Measured using a Macbeth RD-918. The relative reflection density was measured with the paper reflection density set to “0”. As the residual potential increases on multiple copies, the image density decreases. Measurements were taken at the solid black image portion after 10,000 copies each.

A: Black solid image is higher than 1.2 (good)
○: Black solid image is 1.0 or more and 1.2 or less (no problem in practical use)
×: Black solid image is less than 1.0 (practical problem)
The fog density was measured by reflection density of a solid white image using RD-918 manufactured by Macbeth. The reflection density was evaluated by a relative density (the density of A4 paper not printed is 0.000). The measurement was performed on the solid white image portion after 10,000 copies each.

A: Concentration is less than 0.010 (good)
○: Concentration of 0.010 or more and 0.020 or less (a level causing no practical problem)
X: Concentration is higher than 0.020 (a level that causes practical problems)
Dash Mark The state of occurrence of a dash mark (small comet-like streak image) whose periodicity coincides with the period of the photoreceptor on the halftone image was determined according to the following criteria.

A: Frequency of dash marks of 0.4 mm or more: All printed images are 5 / A4 or less (good)
O: Frequency of dash marks of 0.4 mm or more: 1 or more of 6 / A4 or more and 10 / A4 or less (no problem in practical use)
X: Frequency of dash mark image defects of 0.4 mm or more: 11 or more A4 or more occurred (practical problem)
Black spots The periodicity coincided with the period of the photoconductor, and it was determined how many black spots and black streak-like image defects that can be seen per A4 size.

A: Frequency of image defects of 0.4 mm or more: All printed images are 5 / A4 or less (good)
○: Frequency of image defects of 0.4 mm or more: 1 or more of 6 / A4 or more and 10 / A4 or less (no problem in practical use)
X: Frequency of image defects of 0.4 mm or more: 11 or more A4 or more occurred (practical problem)
Scratch image ◎; The surface of the photoconductor is uniformly shaved, and the halftone image is uniform and reproduced as a clean image (good)
○: A small scratch is generated on the surface of the photoreceptor, but the halftone image is reproduced as a uniform and clean image (no problem in practical use)
X: Scratches are generated on the surface of the photoreceptor, and the halftone image is a rough image. (There are practical problems)
Transfer memory 10 images with a mixture of solid black and solid white are continuously printed, and then a uniform halftone image is printed, and the solid black and solid white history appears in the halftone image ( Judgment was made based on whether or not memory was generated (no memory was generated).

  ○: No memory is generated.

  ×: Memory is generated.

  From Table 2, the organophotoreceptor of the present invention, that is, the organic material containing the charge transport layer represented by the polycarbonate having the structural unit represented by the general formula (1) and the charge transport material represented by the general formula (3). The photoconductors 1 to 12 are prevented from generating dash marks, black spots, or transfer memories, and obtain good electrophotographic images having a sufficient image density and a low fog density. On the other hand, the photoconductor 13 of polycarbonate having a charge transport layer of PC-K has many dash marks, the halftone image has deteriorated due to the occurrence of scratches, and the photoconductor of polycarbonate having the charge transport layer of PC-Z. Body 14 has many dash marks. Further, in the photoconductor 15 using CT-R as a charge transport material other than the present invention, a halftone image is deteriorated due to generation of a dash mark and generation of scratches, and a transfer memory is also generated.

Example 2 (Example corresponding to claim 2)
Photoconductors 21 to 35 were produced in the same manner except that the charge transport material of the charge transport layer of each photoconductor of Example 1 was changed as shown in Table 3. These photoreceptors 21 to 36 were evaluated in the same manner as in Example 1. The evaluation results are shown in Table 4.

In Table 3, * 1 uses a charge transport material mixed (CT4-2 / CT3-3 is used at a mass ratio of 6/2)
From Table 4, the organic photoreceptor of the present invention, that is, the organic material containing the charge transport layer represented by the polycarbonate having the structural unit represented by the general formula (1) and the charge transport material represented by the general formula (4). The photoconductors 21 to 32 are prevented from generating dash marks, black spots, or transfer memories, and obtain a good electrophotographic image having a sufficient image density and a low fog density. On the other hand, a polycarbonate photoconductor 33 with a PC-K binder for the charge transport layer has many dash marks, a halftone image has deteriorated due to the occurrence of scratches, and a photoconductor with a polycarbonate with a PC-Z binder for the charge transport layer. The body 34 has many dash marks. Further, in the photoconductor 35 using CT-R as a charge transport material other than the present invention, a halftone image is deteriorated due to generation of a dash mark or scratch, and a transfer memory is also generated.

Example 3 (Example corresponding to claim 3)
Photoconductors 41 to 55 were produced in the same manner except that the charge transport material of the charge transport layer of each photoconductor of Example 1 was changed as shown in Table 5. These photoconductors 41 to 55 were evaluated in the same manner as in Example 1. The evaluation results are shown in Table 6.

  From Table 6, the organic photoreceptor of the present invention, that is, the organic material containing the charge transport layer represented by the polycarbonate having the structural unit represented by the general formula (1) and the charge transport material represented by the general formula (5). The photoconductors 41 to 52 are prevented from generating dash marks, black spots, or transfer memories, and obtain good electrophotographic images having a sufficient image density and a low fog density. On the other hand, the photoconductor 53 of polycarbonate having a charge transport layer of PC-K has many dash marks, the halftone image has deteriorated due to the generation of scratches, and the photosensitivity of polycarbonate having the charge transport layer of binder of PC-Z. The body 54 has many dash marks. Further, in the photoconductor 55 using CT-R as a charge transport material other than the present invention, a halftone image is deteriorated due to generation of a dash mark and generation of scratches, and a transfer memory is also generated.

Example 4 (Example corresponding to claim 4)
Photoconductors 61 to 75 were prepared in the same manner except that the charge transport material of the charge transport layer of each photoconductor of Example 1 was changed as shown in Table 7. These photoreceptors 61 to 75 were evaluated in the same manner as in Example 1. The evaluation results are shown in Table 8.

  * 2 in Table 7 indicates that charge transport materials are mixed (CT5-27 / CT6-28 is used at a mass ratio of 6/2)

  From Table 8, the organophotoreceptor of the present invention, that is, the organic material containing the charge transport layer represented by the polycarbonate having the structural unit represented by the general formula (1) and the charge transport material represented by the general formula (6). The photoconductors 61 to 72 are prevented from generating a dash mark, a black spot, or a transfer memory, and obtain a good electrophotographic image having a sufficient image density and a low fog density. On the other hand, polycarbonate photoconductor 73 with PC-K as the binder for the charge transport layer has many dashes, and halftone images have deteriorated due to the occurrence of scratches. Photosensitivity with polycarbonate with PC-Z as the binder for the charge transport layer. Body 74 has many dash marks. Further, in the photoreceptor 75 using the CT-R other than the present invention as the charge transport material, the halftone image is deteriorated due to the generation of dashes and scratches, and a transfer memory is also generated.

1 is a schematic view in which functions of an image forming apparatus of the present invention are incorporated. 1 is a cross-sectional view of a color image forming apparatus using an organic photoreceptor of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 21 Photoconductor 22 Charging means 23 Developing means 24 Transfer pole 25 Separation pole 26 Cleaning device 30 Exposure optical system 45 Transfer conveyance belt apparatus 50 Fixing means 250 Separation claw unit

Claims (21)

An organic photoreceptor having a charge generation layer containing at least a charge generation material and a charge transport layer containing a charge transport material on a conductive support, wherein the charge transport layer is a structural unit represented by the following general formula (1) An organophotoreceptor comprising a polycarbonate having a charge transport material represented by the following general formula (3):

(In General Formula (1), X is an oxygen atom or a sulfur atom, and R _{1 to} R ₈ represent a hydrogen atom, a halogen atom, a hydroxyl group, or an alkyl group having 1 to 4 carbon atoms.)

(In General Formula (3), Ar ₁ and Ar ₂ represent a substituted or unsubstituted aromatic ring group, R ₁ and R ₂ represent a hydrogen atom or an alkyl group, and R ₃ represents a hydrogen atom, an alkyl group, or a halogen atom. Represents an atom.) An organic photoreceptor having a charge generation layer containing at least a charge generation material and a charge transport layer containing a charge transport material on a conductive support, wherein the charge transport layer is a structural unit represented by the general formula (1) An organophotoreceptor comprising a polycarbonate having a charge transport material represented by the following general formula (4):

(In General Formula (4), Ar ₁ and Ar ₂ represent a substituted or unsubstituted aromatic ring group, R ₄ represents a hydrogen atom, an alkyl group, or a halogen atom, and X represents a vinylene group or an ethylene group. ) An organic photoreceptor having a charge generation layer containing at least a charge generation material and a charge transport layer containing a charge transport material on a conductive support, wherein the charge transport layer is a structural unit represented by the general formula (1) An organophotoreceptor comprising: a polycarbonate having a charge transport material represented by the following general formula (5):

(In the general formula (5), R ₁ and R ₁ ′ each represent a hydrogen atom, an alkyl group, an alkoxy group or a halogen atom, and R ₂ , R ₂ ′, R ₃ and R ₃ ′ each represent a hydrogen atom, Represents an alkyl group, an alkoxy group, a halogen atom or a substituted amino group, and m, m ′, n and n ′ each represent an integer of 1 or 2.) An organic photoreceptor having a charge generation layer containing at least a charge generation material and a charge transport layer containing a charge transport material on a conductive support, wherein the charge transport layer is a structural unit represented by the general formula (1) An organophotoreceptor comprising a polycarbonate having a charge transport material represented by the following general formula (6):

(In the general formula (6), R ₄ represents a hydrogen atom or a methyl group, and Ar ₁ and Ar ₂ are each an aryl group optionally having a halogen atom, an alkyl group, an alkoxy group or a substituted amino group, or Represents a thienyl group, and k represents an integer of 1 or 2.) The organophotoreceptor according to any one of claims 1 to 4, wherein a gallium phthalocyanine pigment is used as the charge generation material of the charge generation layer. The gallium phthalocyanine pigment has a position of at least 7.4 °, 16.6 °, 25.5 °, 28.3 ° in the Bragg angle (2θ ± 0.2 °) of the characteristic X-ray diffraction spectrum of Cu-Kα. 6. The organophotoreceptor according to claim 5, wherein the organophotoreceptor is a chlorogallium phthalocyanine pigment having a characteristic diffraction peak. The gallium phthalocyanine pigment is at least 7.5 °, 9.9 °, 12.5 °, 16.3 °, 18 in the Bragg angle (2θ ± 0.2 °) of the characteristic X-ray diffraction spectrum of Cu-Kα. 6. The organophotoreceptor according to claim 5, wherein the organophotoreceptor is a hydroxygallium phthalocyanine pigment having diffraction peaks characteristic at positions of 6 °, 25.1 °, and 28.1 °. The gallium phthalocyanine pigment is at least 6.8 °, 12.8 °, 15.8 °, 26.6 ° in the Bragg angle (2θ ± 0.2 °) of the characteristic X-ray diffraction spectrum of Cu-Kα. 6. The organophotoreceptor according to claim 5, wherein the organophotoreceptor is a gallium phthalocyanine pigment having a characteristic diffraction peak. The organic photoreceptor according to claim 1, wherein the charge transport layer contains an antioxidant. The organophotoreceptor according to claim 1, further comprising an intermediate layer containing N-type semiconductive particles between the conductive support and the charge generation layer. The organophotoreceptor according to claim 10, wherein the N-type semiconductor particles are a metal oxide. The organophotoreceptor according to claim 10 or 11, wherein the N-type semiconductor particles are titanium oxide or zinc oxide. The organophotoreceptor according to claim 12, wherein the N-type semiconductor particles are titanium oxide. The organophotoreceptor according to claim 13, wherein the titanium oxide is a rutile titanium oxide pigment or an anatase titanium oxide pigment. The organophotoreceptor according to claim 10, wherein the N-type semiconductor particles are subjected to a surface treatment. The organic photoreceptor according to claim 10, wherein the intermediate layer contains a binder of polyamide resin. The organophotoreceptor according to claim 16, wherein the polyamide resin is a polyamide resin having a heat of fusion of 0 to 40 J / g and a water absorption of 5% by mass or less. 18. The organic photoreceptor according to claim 16, wherein a volume ratio of the binder resin and the N-type semiconductor particles in the intermediate layer is N-type semiconductor particles 1 to 2 with respect to the binder resin 1. The organic photoreceptor according to claim 10, wherein the intermediate layer has a thickness of 1 to 10 μm. In a process cartridge used in an image forming apparatus having a charging means for charging by bringing a charging member into contact with an organic photoreceptor, a charge generating layer containing at least a charge generating material and a charge transporting material are contained on a conductive support. At least one of a polycarbonate having a charge transport layer, wherein the charge transport layer has a structural unit represented by the general formula (1), and the charge transport materials represented by the general formulas (3) to (6). An organic photoreceptor containing any one of them, a charging means for charging by bringing a charging member into contact with the organic photoreceptor, a developing means for developing an electrostatic latent image on the organic photoreceptor, and the organic photoreceptor A process cart characterized in that at least one transfer means for transferring a toner image visualized thereon onto a transfer material is integrally supported and is detachably attached to the image forming apparatus main body. Tsu di. In an image forming apparatus having charging means for charging by bringing a charging member into contact with an organic photoreceptor, the organic photoreceptor contains at least a charge generation layer containing a charge generation material and a charge transport material on a conductive support. At least one of a polycarbonate having a charge transport layer, wherein the charge transport layer has a structural unit represented by the general formula (1), and the charge transport materials represented by the general formulas (3) to (6). Any one type is contained, The image forming apparatus characterized by the above-mentioned.

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