JP2007057576A - Organic photoreceptor, image forming method, image forming apparatus, and process cartridge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic photoreceptor capable of forming a good color image over a long period by solving problems, such as the occurrence of voids or an image blur or degradation in image density liable to arise in image forming method of the color image using an intermediate transfer member, an image forming method, an image forming apparatus, and a process cartridge. <P>SOLUTION: The photosensitive layer has a triarylamine group, is indirectly connected to an N atom of the triarylamine group and even more the value of the HOMO electron density distribution determined by an empirical molecular orbital computation using AM1 parameter has at least one or more carbon atom of ≥0.009 and the bipolar moments determined by the empirical molecular orbital computation contains a charge transport material of a compound of ≤0.7 debyes and metal oxide particles. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an organic photoreceptor, an image forming method, and an image forming apparatus that can be applied to an electrophotographic copying machine and printer, and an organic photoreceptor, an image forming method, and an image forming apparatus that can produce an electrophotographic image at high speed. And a process cartridge.

  2. Description of the Related Art Conventionally, in a copying machine using the Carlson method, which is the most typical electrophotographic method, after a photoreceptor is uniformly charged, charges are erased imagewise by exposure to form an electrostatic charge latent image. This electrostatic charge latent image is developed and visualized with toner, and then the toner is transferred to paper or the like and then fixed to form an image.

  Conventionally, as an electrophotographic photoreceptor, an inorganic photoreceptor having an inorganic photoconductive substance such as selenium, zinc oxide, cadmium or the like as a main component of a photosensitive layer has been widely used. However, these inorganic photoreceptors are often harmful and have problems in terms of environmental measures.

  Therefore, in recent years, organic photoreceptors using non-polluting organic substances have been actively developed and widely used. In particular, a function-separated type photoconductor, in which a charge generation function and a charge transport function are assigned to different substances and a compound having desired characteristics can be selected from a wide range, has been actively developed.

  However, the organic photoreceptor is not sufficiently satisfied with the high printing durability of an electrophotographic photoreceptor that is greatly worn away by a cleaning blade or the like and requires a large number of prints. In addition, the active gas such as ozone and NOx generated from the charging process deteriorates the charge transport material and the like, and there is a problem that image density is lowered and image blur is likely to occur due to sensitivity deterioration and residual potential increase. is doing.

  In order to improve the high printing durability, there has been proposed an organic photoreceptor in which inorganic particles such as silica are contained in the surface layer (Patent Document 1). The surface layer of the body easily adsorbs active gases such as ozone and NOx as described above, promotes the deterioration of charge transport materials and the like present in the surface layer, causes image blurring and partial transfer failure of the toner image, Image defects such as voids (partially toner does not transfer from the photoreceptor to the transfer medium and spot-like image defects appear) are likely to occur.

  As a means for preventing the deterioration of the charge transport material or the like by using an active gas such as ozone or NOx, a technique for containing an antioxidant in the charge transport layer of the photoreceptor is well known (Patent Document 2). At present, organic photoreceptors containing inorganic particles do not sufficiently exhibit the effects of these antioxidants.

In recent years, image forming methods using an electrophotographic method have been developed by digital signal processing, and the speed has been increased. In copying machines and printers using cut paper, a copying machine having a printing speed of 50 sheets or more per minute. And printers have been developed.

  As a technology that achieves electrophotographic characteristics for such high-speed printers and copiers, structural optimization calculations are performed using semi-empirical molecular orbital calculations using PM3 parameters to determine the polarizability and dipole moment. An electrophotographic photosensitive member using a charge transport material defined in a specific range has been proposed (Patent Document 3 and Patent Document 4).

  However, as high-speed characteristics are pursued, the chemical structure of the charge transport material tends to become chemically unstable, and in particular, when producing an electrophotographic image, an active gas such as NOx or ozone generated from a charging member or the like. Due to these characteristic deteriorations, there is a problem that image blurring occurs, the residual potential increases, and the image density decreases.

In recent years, the demand for color printing of electrophotographic images has increased with the expansion of use of personal computers and the like, and image forming methods using an intermediate transfer member have been widely developed as image forming methods for color printing. However, in order to obtain a final color image, the intermediate transfer body type image forming method performs primary transfer from the photoreceptor to the intermediate transfer body, secondary transfer from the intermediate transfer body to the transfer material, and at least twice. Since the toner image is transferred, if the surface characteristics of the organic photoconductor are deteriorated by an active gas such as NOx or ozone generated from the charging member, the transferability of the toner image from the organic photoconductor to the intermediate transfer body is reduced. The occurrence of voids or the occurrence of image blur tends to become obvious.
JP-A-8-262755 JP-A-11-200135 Japanese Patent Laid-Open No. 10-312071 JP 2001-305763 A

  The object of the present invention is to solve the problems of the prior art as described above. That is, it is to provide an organic photoreceptor having high speed characteristics and active gas resistance, and to provide a high printing durability organic photoreceptor capable of producing a good electrophotographic image. Another object of the present invention is to provide an organic photoreceptor that prevents the occurrence of voids and is high-speed and has excellent active gas resistance. Another object of the present invention is to provide a process cartridge, an image forming method, and an image forming apparatus using the organic photoreceptor.

  In addition, the present invention improves the problems such as the occurrence of voids, image blurring, or a decrease in image density, which are likely to occur in a color image forming method using an intermediate transfer member. An organic photoreceptor, an image forming method, an image forming apparatus, and a process cartridge.

As a result of detailed examination of the above problems, the present inventors have found a specific relationship between the chemical structure of the charge transport material and the electron density distribution that can achieve both high speed characteristics and gas resistance characteristics, and completed the present invention. did. That is, the use of a charge transport material having a specific relationship with a HOMO electron density distribution obtained by semi-empirical molecular orbital calculation using the AM1 parameter and a metal oxide particle together with a large electron cloud spread. As a result, it was found that an organic photoreceptor capable of forming a good monochrome image and color image while maintaining high speed characteristics and having excellent gas resistance and high printing durability, and completed the present invention. That is, the above object of the present invention is achieved by using the following configuration.
1. In an organic photoreceptor for use in an image forming method in which a uniform charge is imparted on an organic photoreceptor in a charging process, an electrostatic latent image is formed in an image exposure process, and the electrostatic latent image is visualized as a toner image in a development process. A photosensitive layer containing at least a charge generation material and a charge transport material on a conductive substrate, the photosensitive layer having a triarylamine group and indirectly linked to the N atom of the triarylamine group; In addition, on the farthest carbocyclic group, it has at least one carbon atom having a HOMO electron density distribution value of 0.009 or more determined by semiempirical molecular orbital calculation using the AM1 parameter, An organophotoreceptor comprising a charge transport material and metal oxide particles of a compound having a dipole moment determined by the semi-empirical molecular orbital calculation of 0.7 debye or less.
2. A charging process for charging the organic photoreceptor, a latent image forming process for forming an electrostatic latent image on the charged organic photoreceptor, a developing process for visualizing the electrostatic latent image into a toner image, and the visualized image In an organic photoconductor used in an image forming method, the method includes a primary transfer step of transferring a toner image from an organic photoconductor onto an intermediate transfer member, and a secondary transfer step of transferring a toner image on the intermediate transfer member to a transfer material. A photosensitive layer containing at least a charge generating material and a charge transporting material on the conductive substrate, the photosensitive layer having a triarylamine group and indirectly linked to the N atom of the triarylamine group, On the farthest carbocyclic group, it has at least one carbon atom having a HOMO electron density distribution value of 0.009 or more determined by semiempirical molecular orbital calculation using AM1 parameter, and Semi-empirical Organic photoreceptor, wherein a dipole moment found by the trajectory calculation contains a charge transporting material and the metal oxide particles of 0.7 Debye following compounds.
3. 3. The organophotoreceptor according to 1 or 2 above, wherein the carbocyclic group is a phenyl group.
4). Any one of the above 1 to 3, wherein the photosensitive layer has a structure in which a charge generation layer containing a charge generation material and a charge transport layer containing a charge transport material laminated thereon are laminated. The organic photoreceptor described in 1.
5. 5. The organophotoreceptor according to any one of 1 to 4, wherein the charge transport material has an ionization potential of 7.6 to 7.9 eV.
6). 6. The organophotoreceptor according to any one of 1 to 5 above, wherein the number average primary particle size (Dp) of the metal oxide particles is in the range of 0.010 μm <Dp <1.00 μm.
7). 7. The organophotoreceptor according to any one of items 1 to 6, wherein the metal oxide particles are at least one selected from titanium oxide, zinc oxide, alumina, and silica.
8). 8. The organophotoreceptor according to any one of 1 to 7 above, wherein the charge transport material and metal oxide particles are contained in a surface layer.
9. In an image forming method, a uniform charge is imparted on an organic photoreceptor in a charging step, an electrostatic latent image is formed in an image exposure step, and the electrostatic latent image is visualized as a toner image in a development step. Has a photosensitive layer containing at least a charge generating material and a charge transporting material on a conductive substrate, the photosensitive layer has a triarylamine group and is indirectly linked to the N atom of the triarylamine group, In addition, on the farthest carbocyclic group, it has at least one carbon atom having a HOMO electron density distribution value of 0.009 or more determined by semiempirical molecular orbital calculation using the AM1 parameter, An image forming method comprising: a compound having a dipole moment obtained by the semi-empirical molecular orbital calculation of 0.7 debye or less and a charge transport material and metal oxide particles.
10. A charging process for charging the organic photoreceptor, a latent image forming process for forming an electrostatic latent image on the charged organic photoreceptor, a developing process for visualizing the electrostatic latent image into a toner image, and the visualized image In an image forming method comprising a primary transfer step of transferring a toner image from an organic photoreceptor onto an intermediate transfer member and a secondary transfer step of transferring the toner image on the intermediate transfer member onto a transfer material, the organic photoreceptor is conductive A photosensitive layer containing at least a charge generation material and a charge transport material on the substrate, the photosensitive layer having a triarylamine group and indirectly linked to an N atom of the triarylamine group, A carbocyclic group present at a distance has at least one carbon atom having a HOMO electron density distribution value of 0.009 or more determined by semiempirical molecular orbital calculation using the AM1 parameter; Empirical molecular orbital meter The image forming method of dipole moment obtained is characterized by containing the charge-transporting material and the metal oxide particles of the following compounds 0.7 Debye by.
11. An organic photoreceptor, a charger for uniformly charging the organic photoreceptor, an image exposure unit for forming an electrostatic latent image on the organic photoreceptor, and a developer for developing the electrostatic latent image into a toner image In the image forming apparatus, the organic photoreceptor has a photosensitive layer containing at least a charge generation material and a charge transport material on a conductive substrate, the photosensitive layer has a triarylamine group, and the triarylamine group The value of the HOMO electron density distribution obtained by the semi-empirical molecular orbital calculation using the AM1 parameter is 0.009 or more on the carbocyclic group that is indirectly linked to the N atom of It contains a charge transport material and metal oxide particles of a compound having at least one carbon atom and having a dipole moment determined by the semi-empirical molecular orbital calculation of 0.7 debye or less. Picture Forming apparatus.
12 12. The image forming apparatus as described in 11 above, wherein the process speed is 400 mm / sec or more.
13. An organic photoreceptor, a charger for uniformly charging the organic photoreceptor, an image exposure unit for forming an electrostatic latent image on the organic photoreceptor, and a developer for developing the electrostatic latent image into a toner image A process cartridge for use in an image forming apparatus having a photosensitive layer containing at least a charge generating substance and a charge transporting substance on a conductive substrate, the photosensitive layer having a triarylamine group, and the triarylamine group The value of the HOMO electron density distribution obtained by the semi-empirical molecular orbital calculation using the AM1 parameter is 0.009 or more on the carbocyclic group that is indirectly linked to the N atom of It contains a charge transport material and metal oxide particles of a compound having at least one carbon atom and having a dipole moment determined by the semi-empirical molecular orbital calculation of 0.7 debye or less. The photoconductor and at least one of charging means, latent image forming means, developing means, transfer means, charge eliminating means, and cleaning means are integrally supported, and can be detachably attached to the image forming apparatus main body. Feature process cartridge.

  By using the organophotoreceptor of the present invention, it is possible to provide an organophotoreceptor that can be sufficiently adapted to a color copier using a high-speed copying machine or an intermediate transfer member, and that is excellent in active gas resistance and high printing durability. An image forming method, an image forming apparatus, and a process cartridge using the organophotoreceptor can be provided that can provide a satisfactory electrophotographic image having sufficient density and preventing occurrence of image blurring and voids. it can.

The organophotoreceptor of the present invention imparts a uniform charge on the organophotoreceptor in the charging process, imparts a uniform charge on the static organophotoreceptor in the charging process in the image exposure process, and produces an electrostatic latent image in the image exposure process. An organic photoreceptor used in an image forming method for forming and developing an electrostatic latent image into a toner image in a development process, and having a photosensitive layer containing at least a charge generating substance and a charge transporting substance on a conductive substrate. A semi-empirical molecule in which the photosensitive layer has a triarylamine group and is indirectly linked to the N atom of the triarylamine group, and the AM1 parameter is used on the farthest carbocyclic group. The value of the HOMO electron density distribution obtained by orbital calculation has at least one carbon atom of 0.009 or more, and the dipole moment obtained by the semiempirical molecular orbital calculation is 0.7 debye or less. Compound charge transport Characterized in that it contains the quality and metal oxide particles.

  Since the organic photoconductor has the above-described configuration, it exhibits high-speed sensitivity characteristics and stable potential characteristics even when a large number of prints or color copies are made, and the increase in residual potential due to an active gas such as NOx is small. In addition, it is possible to prevent the occurrence of image blurring and voids, or the reduction in image density, and to stably produce an electrophotographic image with good sharpness.

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

  In the present invention, the organic photoconductor means an electrophotographic photoconductor configured to have an organic compound having either a charge generation function or a charge transport function essential for the configuration of the electrophotographic photoconductor, It contains all known organic electrophotographic photoreceptors such as a photoreceptor composed of a known organic charge generating material or organic charge transport material, a photoreceptor composed of a polymer complex with a charge generating function and a charge transport function.

  The layer structure of the organic photoreceptor of the present invention preferably has a charge generation layer and a charge transport layer on a conductive support, and the charge transport layer is preferably formed of a plurality of layers. Moreover, it is preferable to provide an intermediate layer between the conductive support and the charge generation layer, which can block the entry of free carriers from the support. Hereinafter, preferred configurations of the organic photoreceptor of the present invention are shown.

Conductive Support The conductive support used in the photoreceptor of the present invention may be either a sheet or a cylinder, but in order to design an image forming apparatus in a compact manner, a cylindrical conductive support is used. Is preferred.

  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 roundness and shake range 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.

  As the conductive support used in the present invention, one having an alumite film that has been sealed on the surface thereof may be used. The alumite treatment is usually performed in an acidic bath such as chromic acid, sulfuric acid, oxalic acid, phosphoric acid, boric acid, sulfamic acid, etc., but anodizing treatment in sulfuric acid gives the most preferable result. In the case of anodizing treatment in sulfuric acid, the sulfuric acid concentration is preferably 100 to 200 g / L, the aluminum ion concentration is 1 to 10 g / L, the liquid temperature is about 20 ° C., and the applied voltage is preferably about 20 V. It is not limited. The average film thickness of the anodized film is usually 20 μm or less, particularly preferably 10 μm or less.

Intermediate Layer In the present invention, it is preferable to provide an intermediate layer that can block the entry of free carriers from the support between the conductive support and the photosensitive layer.

  In the present invention, in order to improve the adhesion between the conductive support and the photosensitive layer, or to prevent charge injection from the support, an intermediate layer (including an undercoat layer) is provided between the support and the photosensitive layer. Including) can also be provided. Examples of the material for the intermediate layer include polyamide resins, vinyl chloride resins, vinyl acetate resins, and copolymer resins containing two or more of these resin repeating units. Of these subbing resins, a polyamide resin is preferable as a resin capable of reducing the increase in residual potential due to repeated use. The film thickness of the intermediate layer using these resins is preferably 0.01 to 0.5 μm.

  Examples of the intermediate layer preferably used in the present invention include an intermediate layer using a curable metal resin obtained by thermosetting an organic metal compound such as a silane coupling agent or a titanium coupling agent. As for the film thickness of the intermediate | middle layer using curable metal resin, 0.1-2 micrometers is preferable.

  An intermediate layer preferably used in the present invention includes an intermediate layer in which inorganic particles are dispersed in a binder resin. The average particle diameter of the inorganic particles is preferably 0.01 to 1 μm. In particular, an intermediate layer in which N-type semiconductive fine particles subjected to surface treatment are dispersed in a binder is preferable. For example, an intermediate layer in which titanium oxide having an average particle size of 0.01 to 1 μm, which has been surface-treated with silica / alumina treatment and a silane compound, is dispersed in a polyamide resin. The film thickness of such an intermediate layer is preferably 1 to 20 μm.

  The N-type semiconducting fine particles are fine particles having the property of using conductive carriers as electrons. That is, the property that the conductive carrier is an electron is that the N-type semiconducting fine particles are contained in an insulating binder to effectively block hole injection from the substrate, and to convert electrons from the photosensitive layer into electrons. On the other hand, it has the property which does not show blocking property.

Specific examples of the N-type semiconductive fine particles include fine particles such as titanium oxide (TiO ₂ ) and zinc oxide (ZnO). In the present invention, titanium oxide is particularly preferably used.

  The average particle diameter of the N-type semiconducting fine particles used in the present invention is preferably in the range of 10 nm to 500 nm in the number average primary particle diameter, more preferably 10 nm to 200 nm, and particularly preferably 15 nm to 50 nm. .

  The intermediate layer using N-type semiconducting fine particles whose number average primary particle size is within the above range can be finely dispersed in the layer, has sufficient potential stability, and generates black spots. Has a prevention function.

  For example, in the case of titanium oxide, the number-average primary particle size of the N-type semiconducting fine particles is magnified 10,000 times by observation with a transmission electron microscope, and 100 particles are randomly observed as primary particles. It is measured as the number average diameter.

  The shape of the N-type semiconducting fine particles used in the present invention includes dendritic, needle-like, and granular shapes. For example, in the case of titanium oxide particles, the N-type semiconductive fine particles have a crystalline form. There are anatase type, rutile type and amorphous type, but any crystal type may be used, or two or more crystal types may be mixed and used. Of these, the rutile type is the best.

  One of the hydrophobizing surface treatments performed on the N-type semiconducting fine particles is a plurality of surface treatments, and the last surface treatment is a surface treatment with a reactive organosilicon compound. Is to do. In addition, at least one of the surface treatments is at least one surface treatment selected from alumina, silica, and zirconia, and finally the surface treatment of the reactive organosilicon compound is performed. It is preferable.

  Alumina treatment, silica treatment, and zirconia treatment are treatments for precipitating alumina, silica, or zirconia on the surface of the N-type semiconductive fine particles. Alumina, silica, and zirconia deposited on these surfaces include alumina, silica, Zirconia hydrates are also included. The surface treatment of the reactive organosilicon compound means using a reactive organosilicon compound in the treatment liquid.

  In this way, the surface treatment of the N-type semiconductive fine particles such as titanium oxide particles was performed at least twice, so that the surface of the N-type semiconductive fine particles was uniformly coated (treated), and the surface treatment was performed. When N-type semiconducting fine particles are used in the intermediate layer, a good photoconductor having good dispersibility of N-type semiconductive fine particles such as titanium oxide particles in the intermediate layer and causing no image defects such as black spots. You can get it.

Photosensitive Layer The photosensitive layer configuration of the organic photoreceptor of the present invention has a photosensitive layer containing at least a charge generating substance and a charge transporting substance on a conductive substrate. The photosensitive layer may be composed of a photosensitive layer in which the charge generation material and the charge transport material are present in the same layer, but more preferably, a charge generation layer (CGL) containing a charge generation material on a conductive support and A stacked structure of a charge transport layer (CTL) containing a charge transport layer is preferred. Hereinafter, the organic photoreceptor of the present invention will be described focusing on the layer structure of the laminated structure.

Charge generation layer 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.

  A known charge generation material (CGM) can be used as the charge generation material (CGM). For example, a phthalocyanine pigment, an azo pigment, a perylene pigment, an azulenium pigment, or the like can be used. Among these, the CGM that can minimize the increase in residual potential due to repeated use has a three-dimensional and potential structure that can form a stable aggregate structure among a plurality of molecules. Specifically, a phthalocyanine having a specific crystal structure. CGM of pigments and perylene pigments. For example, CGM such as titanyl phthalocyanine having a maximum peak at a Bragg angle 2θ of 27.2 ° with respect to Cu-Kα ray and benzimidazole perylene having a maximum peak at 2θ of 12.4 has little deterioration due to repeated use. Potential increase can be reduced.

  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 2 μm.

Charge Transport Layer The charge transport layer according to the present invention has a triarylamine group and is indirectly linked to the N atom of the triarylamine group, and further, on the farthest carbocyclic group, the AM1 parameter Having at least one carbon atom having a HOMO electron density distribution value of 0.009 or more determined by semi-empirical molecular orbital calculation using a dipole, and a dipole moment determined by the calculation of 0.7 debye or less The charge transport material of the compound is used in combination with the compound of the general formula (1). That is, in the charge transport material of the present invention, the HOMO electron density distribution value is indirectly linked to the N atom of the triarylamine group, and 0.009 or more carbon atoms are present on the farthest carbocyclic group. Have at least one. Further, the value of the HOMO electron density distribution is in the range of 0.009 to 0.03, which is chemically most stable (is a chemically stable structure that is unlikely to be an attack site such as NOx) and high-speed transport of charge carriers. A chemical structure that satisfies the characteristics can be obtained.

  Here, the compound having a triarylamine group is a compound having at least a triarylamine group in the molecular structure, and for example, a compound represented by the following general formula (1) is preferably used.

[In the general formula (1), R ¹ , R ² , R ³ , R ⁴ and R ⁵ are each a hydrogen atom, an alkyl group having 1 to 4 carbon atoms or an alkoxy group. Ar ¹ represents a hydrogen atom or a substituted or unsubstituted aromatic group, and Ar ² represents a substituted or unsubstituted aromatic group. ]
In general formula (1), the structure of the triarylamine group is composed of three phenyl groups linked to the N atom.

  Many of the compounds represented by the general formula (1) have a cis-cis, cis-trans, and trans-trans stereoisomeric structure, and satisfy the conditions of the HOMO electron density and the dipole moment. Many of these compounds have a trans-trans stereoisomeric structure. When the compound of the above general formula (1) is used as the charge transport material of the present invention, a compound having a trans-trans stereoisomeric structure may be used. preferable.

  The compounds having these three-dimensional structures preferably contain 50% by mass or more of compounds having a three-dimensional structure that satisfies the above conditions of HOMO and dipole moment after separating these three-dimensional structures once.

  Moreover, about the synthesis example of the compound of General formula (1), and its isolation | separation method (Separation method of the stereoisomeric structure of cis-cis, cis-trans, trans-trans), Unexamined-Japanese-Patent No. 2003-280221 WHEREIN Can be separated under the liquid chromatography measurement conditions (separation conditions) described above, and separated from this, indirectly linked to the N atom of the triarylamine group and on the farthest carbocyclic group. It is preferable to select a compound which is a compound having at least one carbon atom of 009 or more and a dipole moment obtained by the calculation of 0.7 debye or less.

Measuring machine: Shimadzu LC6A (manufactured by Shimadzu Corporation)
Column: CLC-SIL (manufactured by Shimadzu Corporation)
Detection wavelength: 290 nm
Mobile phase: n-hexane / dioxane = 10-500 / 1
Mobile phase flow rate: about 1 ml / min
Sample solvent: n-hexane / dioxane = 10/1
Sample: 3 mg / solvent 10 ml
The farthest carbocyclic group that is indirectly linked to the N atom is a carbocyclic group that is indirectly connected to the N atom of the triarylamine group via another group, and A carbocyclic group having the farthest distance in the molecule from the N atom centering on the N atom is shown, and in the following compound (CTM-2), it corresponds to a phenyl group surrounded by circles of P1 and P2.

  Examples of the carbocyclic group include monocyclic carbocyclic groups (saturated carbocyclic groups and aromatic carbocyclic groups), condensed polycyclic carbocyclic groups, and the like. In the present invention, carbocyclic groups such as phenyl groups are used. Is preferably used.

  The HOMO electron density distribution and dipole moment obtained by semiempirical molecular orbital calculation using the AM1 parameter were obtained by semiempirical molecular orbital calculation as follows.

  That is, in the molecular orbital method, a wave function used in the Schrodinger equation is approximated by a slater determinant composed of molecular orbitals represented by linear combination of atomic orbitals, and the molecular orbits constituting the wave function are in a consistent field (self). Various physical quantities can be calculated as the total energy, wave function, and expected value of the wave function by using an approximation of -consistent field (abbreviated as SCF). The semi-empirical molecular orbital method shortens the calculation time by parameterizing and approximating the integral calculation, which requires a long calculation time, using various experimental values when calculating the molecular orbital by approximating the appropriate field. In the present invention, the AM1 parameter set was used as a semi-empirical parameter, and the calculation was performed using a version MOPAC 93 of a semi-empirical molecular orbital calculation program MOPAC (for PM3 and MOPAC, JJ P Stewart, Journal of Computer-Aided Molecular Design, 4, 1 (1990) and references cited therein).

  HOMO electron density distribution obtained by semi-empirical molecular orbital calculation using AM1 parameter, which is a compound having a triarylamine group, indirectly linked to the N atom of the triarylamine group and present at the farthest position Specific examples of the compound in which at least one carbon atom of 0.009 or more is present on the carbocyclic group and the dipole moment obtained by the above calculation is 0.7 debye or less include the following compounds: Is mentioned.

  The compounds shown in the specific examples can be selected from the compounds represented by the general formula (1), and all of the compounds of the general formula (1) have the above-mentioned electron density distribution and dipole moment conditions. It is necessary to select a compound satisfying the above conditions from the compound represented by the general formula (1).

Among the compounds represented by the general formula (1), a compound having an alkyl group having 1 to 4 carbon atoms in at least one of R ^{1 to} R ⁵ satisfies the above conditions of electron density distribution and dipole moment. In particular, a compound having an alkyl group having 1 to 4 carbon atoms in R ₂ is preferable for satisfying the above conditions.

  As a charge transport material according to the present invention, it is a necessary condition to use the above-mentioned compounds. However, these compounds can be used together with a charge transport material that does not satisfy the above conditions. However, even when used in combination, it is preferable to use a charge transport material satisfying the above conditions as the main charge transport material (50% or more by mass ratio of the total charge transport material).

  It is preferable that the ionization potential (ionization potential obtained by semiempirical molecular orbital calculation using the AM1 parameter) of the charge transport material according to the present invention is 7.6 to 7.9 eV.

  In particular, when a titanyl phthalocyanine pigment having a maximum peak at a Bragg angle 2θ of 27.2 ° with respect to the Cu—Kα ray is used as the charge generating material, by applying a compound having an ionization potential in the above range as a charge transporting material, Even in a high-speed process of 400 mm / sec or more, an increase in residual potential can be suppressed to be small, image blurring and voids can be prevented, and a good electrophotographic image can be produced at a high density.

  The metal oxide particles according to the present invention are preferably contained in the charge transport layer in combination with the charge transport material according to the present invention. By forming a charge transport layer using both of these charge transport materials and metal oxide particles as the surface layer of the photoreceptor, it is possible to form a high printing durability organic photoreceptor that prevents image blurring and voids at high speed. it can.

  The metal oxide particles are preferably metal oxides (including transition metal oxides) such as titanium oxide, zinc oxide, alumina, and silica. Of these, titanium oxide and alumina are preferably used, and alumina is most preferable.

  These metal oxide particles are known to block the hydroxyl groups present on the surface and use them in the surface layer of the organophotoreceptor. In the present invention, the average blocking level of the hydroxyl groups is more complete. In order to achieve this, it is preferable to improve the surface treatment of the metal oxide particles.

  The metal oxide particles are preferably fired and strengthened. For example, since it is difficult to perform a hydrophobizing treatment with alumina that has not been subjected to firing strengthening, firing-strengthened alumina is preferable as the alumina subjected to the multiple surface treatment of the present invention. In the case of fired reinforced alumina, a material fired at a temperature of usually 500 ° C. or higher, preferably 1000 ° C. or higher is used in order to give sufficient strength. The firing time is preferably 5 hours or longer, more preferably 10 hours or longer. By firing alumina under the above temperature conditions, functional groups such as hydroxyl groups present on the surfaces of the alumina particles are decomposed to form aluminum oxide. As a result, the specific surface area of the alumina particles is reduced, and when the hydrophobization treatment is performed with a silane compound or the like, the surface treatment can be effectively performed.

  Fine particles having a number average primary particle size (Dp) of metal oxide particles in the range of 0.010 μm <Dp <1.00 μm are used. In particular, 0.015 μm <Dp <0.85 μm is preferable. The number average primary particle size (Dp) is a measured value as the average diameter in the ferret direction by image analysis, in which fine particles are magnified 10,000 times by observation with a transmission electron microscope, 100 particles are randomly observed as primary particles, and image analysis is performed. is there. Metal oxide particles having a number average primary particle size (Dp) of 0.010 μm or less are difficult to uniformly disperse in the surface layer, and easily form aggregated particles. It tends to increase, causing a decrease in image density and occurrence of image blur. On the other hand, metal oxide particles having a number average primary particle size (Dp) of 1.00 μm or more are likely to have large irregularities on the surface layer, and active gas (ozone or NOx) is likely to adhere to these large irregularities. Blur is likely to occur. In addition, metal oxide particles having a number average primary particle size (Dp) of 1.00 μm or more are likely to precipitate in the dispersion and easily generate aggregates.

  In the present invention, the surface treatment of metal oxide particles means that the surface of the metal oxide particles is coated with an organic compound, an organometallic compound, a fluorine compound, a reactive organosilicon compound, or the like. The surface of the metal oxide particles is covered with an organic compound, an organometallic compound, a fluorine compound, a reactive organosilicon compound, or the like. Photoelectron spectroscopy (ESCA), Auger electron spectroscopy (Auger), secondary ion mass spectrometry This is confirmed with high accuracy by using a combination of surface analysis methods such as SIMS and diffuse reflection FI-IR.

  The surface treatment of the metal oxide particles can be performed by a wet method. For example, metal oxide particles are dispersed in water to form an aqueous slurry, and this aqueous slurry is mixed with a water-soluble silicate, a water-soluble aluminum compound, or the like. 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. In the surface treatment with a reactive organosilicon compound, a solution obtained by dissolving or suspending a reactive organosilicon compound in an organic solvent or water is mixed with metal oxide particles, and this solution is stirred for several minutes to 1 hour. And depending on the case, after heat-processing this liquid, it passes through processes, such as filtration, It dries, The metal oxide particle which coat | covered the surface with the organosilicon compound can be obtained. In the surface treatment with a fluorine compound, an organic silicon compound having a fluorine atom in an organic solvent or water is dissolved or suspended, the suspension is mixed with metal oxide particles, and the mixed solution is mixed for several minutes to 1 hour. After stirring and mixing to some extent, and optionally heat treatment, it is dried through a process such as filtration and coated with a fluorine compound. The surface-treated alumina of the present invention is subjected to surface treatment for improving dispersibility in a certain layer to improve the stability of the coating solution containing the particles. For this purpose, the slipperiness and surface properties are improved by treating with silicone oil or silicone resin.

  Preferable examples of the multiple surface treatments according to the present invention are oxide particles in which the primary treatment is a surface treatment with a halogenated silane and the final treatment is a surface treatment of a silazane compound.

  Oxide particles obtained by performing a surface treatment with a silicone oil as a primary treatment and a surface treatment with a silazane compound as a final treatment are also preferable. For example, a primary surface treatment is performed with a halogenated silane or a silicone oil-based treatment agent, the primary treatment powder is crushed, and the crushed powder is further subjected to a secondary surface treatment with an alkylsilazane-based treatment agent. Oxide particles having an improved hydrophobicity distribution can be obtained.

  The primary surface treatment with the halogenated silanes or the silicone oil-based treatment agent, and the secondary surface treatment with the alkylsilazane-based treatment agent after the crushing treatment may be either a dry treatment or a wet treatment. However, if the order of the primary surface treatment and the secondary surface treatment are different, or if the final treatment agent, amount used, treatment method, etc. are not appropriate, the hydrophobicity and hydrophobicity distribution cannot be improved. The object of the present invention cannot be achieved. In particular, when the final treatment is other than silazane compounds, the surface treatment tends to be detached with time and the hydrophobicity distribution tends to be large.

  By performing such surface treatments a plurality of times, the degree of hydrophobicity and the degree of hydrophobicity distribution of the oxide particles can be improved, and it is possible to effectively prevent a decrease in image density and occurrence of image blurring or transfer memory. be able to.

  The surface layer metal oxide particles according to the present invention preferably have a degree of hydrophobicity of 66% (vol.%) Or more. When the degree of hydrophobicity of the metal oxide particles is less than 66% (vol.%), There are many hydroxyl groups present on the surface of the metal oxide particles, and the humidity characteristics of the potential characteristics (charging potential, residual potential, etc.) are large, In addition, image unevenness due to image blurring and transfer memory is likely to occur. The degree of hydrophobicity of the metal oxide particles is more preferably 70% or more.

  The metal oxide particles in the surface layer according to the present invention preferably have a hydrophobicity distribution value of 20% (vol.%) Or less. When the hydrophobicity distribution value is larger than 20% (vol.%), Metal oxide particles having many hydroxyl groups remaining on the surface are included, and image blurring and transfer memory are likely to occur.

  In addition, it describes about said hydrophobicity (methanol wettability) and hydrophobicity distribution value.

  The degree of hydrophobicity (methanol wettability) is a measure of wettability with methanol. That is, it is defined as follows.

Hydrophobicity (methanol wettability) = (a / (a + 50)) × 100
The method for measuring the degree of hydrophobicity is described below.

  0.2 g of metal oxide particles to be measured are weighed and added to 50 ml of distilled water placed in a beaker having an inner volume of 200 ml. Methanol is slowly added dropwise from a burette whose tip is immersed in a liquid until the entire metal oxide particles are wetted (until they all settle) with slow stirring. When the amount of methanol necessary to wet the entire metal oxide particles is a (ml), the degree of hydrophobicity is calculated by the above formula.

Measuring method of hydrophobicity distribution value 1) Weigh 0.2 g of metal oxide particles to be measured and put into a centrifuge tube.

(Prepare one for each point you want to plot)
2) Put methanol solutions of different concentrations into each 7 ml centrifuge tube with Komagome pipette and tighten (use the methanol concentration determined by the above hydrophobization degree for total precipitation).

  3) Disperse at 90 rpm with a tumbler mixer for 30 seconds.

4) Centrifuge (3500 rpm, 10 minutes)
5) Read the sedimentation volume, and determine each sedimentation volume% when the total sedimentation volume (the total sedimentation volume) is 100%.

  6) Based on the above measured values, a graph of the horizontal axis methanol concentration (Vol.%) And the vertical axis sedimentation volume (Vol.%) Is prepared.

  From the above measurement, the hydrophobicity distribution is measured, and the hydrophobicity distribution value is defined as follows.

{(Methanol Vol.% With a sedimentation volume of 100%)
-(Methanol Vol.% With a sedimentation volume of 10%)} ≦ 25
The hydrophobization degree distribution curve is shown in FIG. In the distribution curve of FIG. 1, the methanol concentration at point a represents the degree of hydrophobicity, the difference between the methanol concentration at point a and the methanol concentration at point b; Δ (ab) represents the hydrophobicity distribution value of the present invention. .

  Next, the surface treatment agent used for the primary surface treatment or the secondary surface treatment of the present invention will be described.

  Examples of the silicone oil-based treating agent preferably used in the primary treatment of the present invention include straight silicone oils such as dimethyl silicone oil, methylphenyl silicone oil, and methylhydrogen silicone oil, amino-modified silicone oil, epoxy-modified silicone oil, and carboxyl-modified silicone oil. , Carbinol-modified silicone oil, methacryl-modified silicone oil, mercapto-modified silicone oil, phenol-modified silicone oil, one-end reactive modified silicone oil, heterogeneous functional group-modified silicone oil, polyether-modified silicone oil, methylstyryl-modified silicone oil, alkyl Modified silicone oil, higher fatty acid ester modified silicone oil, hydrophilic special modified silicone oil, Kokishi modified silicone oil, higher fatty acid containing modified silicone oil, it is possible to use modified silicone oils and fluorine modified silicone oil. Moreover, you may mix 2 or more types according to the objective.

  Examples of halogenated silanes include dimethyldichlorosilane, monochlorosilane, dichlorosilane, trichlorosilane, and tetrachlorosilane.

  Silazanes used in the final surface treatment agent include hexamethyldisilazane, hexaethyldisilazane, hexapropyldisilazane, hexabutyldisilazane, hexapentyldisilazane, hexahexyldisilazane, hexacyclohexyldisilazane, Hexaphenyldisilazane, divinyltetramethyldisilazane, dimethyltetravinyldisilazane, etc. can be used.

In addition to the above silicone oil-based treatment agents and halogenated silanes, the following alkoxysilanes, siloxanes, metal alkoxides, fatty acids and metal salts thereof are used as surface treatment agents before the final surface treatment of silazanes. May be.
Alkoxysilanes include tetramethoxysilane, tetraethoxysilane, methyltrimethoxysilane, dimethyldimethoxysilane, methyltriethoxysilane, phenyltrimethoxysilane, diphenyldimethoxysilane, o-methylphenyltrimethoxysilane, p-methylphenyltri Methoxysilane, n-butyltrimethoxysilane, i-butyltrimethoxysilane, hexyltrimethoxysilane, octyltrimethoxysilane, decyltrimethoxysilane, dodecyltrimethoxysilane, tetraethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane , Phenyltriethoxysilane, diphenyldiethoxysilane, i-butyltriethoxysilane, decyltriethoxysilane, vinyltriethoxysilane, γ Methacryloxypropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-chloropropyltrimethoxysilane, γ-aminopropyltrimethoxysilane Γ-aminopropyltriethoxysilane, γ- (2-aminoethyl) aminopropyltrimethoxysilane, γ- (2-aminoethyl) aminopropylmethyldimethoxysilane, and the like.

  Examples of siloxanes include siloxanes such as hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, hexamethyldisiloxane, and octamethyltrisiloxane.

  Metal alkoxides include trimethoxyaluminum, triethoxyaluminum, tri-i-propoxyaluminum, tri-n-butoxyaluminum, tri-s-butoxyaluminum, tri-t-butoxyaluminum, mono-s-butoxydi-i-propyl Aluminum, tetramethoxy titanium, tetraethoxy titanium, tetra-i-propoxy titanium, tetra-n-propoxy titanium, tetra-n-butoxy titanium, tetra-s-butoxy titanium, tetra-t-butoxy titanium, tetraethoxy zirconium, tetra -I-propoxyzirconium, tetra-n-butoxyzirconium, dimethoxytin, diethoxytin, di-n-butoxytin, tetraethoxytin, tetra-i-propoxytin, tetra-n-butoxytin, dietoxy Zinc, magnesium methoxide, magnesium ethoxide, magnesium isopropoxide, and the like.

Fatty acids and their metal salts include undecyl acid, lauric acid, tridecyl acid, dodecyl acid, myristic acid, palmitic acid, pentadecylic acid, stearic acid, heptadecylic acid, arachidic acid, montanic acid, oleic acid, linoleic acid, arachidonic acid, etc. The long-chain fatty acid is a salt of a metal such as zinc, iron, magnesium, aluminum, calcium, sodium, or lithium.
These treatment agents may be used by diluting with hexane, toluene, alcohol (methanol, ethanol, propanol, etc.), acetone, or the like, depending on circumstances.

  Specific procedures for surface treatment; for example, alumina powder is put into a solvent (preferably adjusted to pH 4 with an organic acid or the like) in which silicone oil is dissolved, and then the solvent is removed, followed by crushing treatment. . Thereafter, the pulverized treated powder is put into a solvent in which the silazane compound is dissolved and reacted, and then the solvent is removed and pulverization is performed. Further, the following method may be used. For example, put alumina powder in a reaction vessel, add alcohol water while stirring in a nitrogen atmosphere, introduce a silicone oil treatment liquid such as organopolysiloxane into the reaction vessel, perform surface treatment, and further heat and stir. Remove the solvent. Then, after crushing treatment, while stirring in a nitrogen atmosphere, an alkylsilazane-based treatment solution is introduced to perform surface treatment, and further heated and stirred to remove the solvent and then cooled. The treatment conditions are adjusted so that the alumina powder has the hydrophobicity, the degree of hydrophobicity and the distribution frequency.

  In addition, these treatment agents can be used by diluting with hexane, toluene, alcohol (methanol, ethanol, propanol, etc.), acetone, etc., or with water depending on the case.

  The charge transport layer according to the present invention preferably contains an antioxidant. As the antioxidant, the following compounds are preferred.

  Such an antioxidant is particularly preferably used because it can effectively exhaust the active gas that is easily adsorbed in the surface layer.

  The charge transport layer according to the present invention is preferably composed of one layer or two layers on the upper and lower sides. When the charge transport layer is composed of two layers, the charge transport material of the present invention is preferably used for the upper charge transport layer. That is, by using the charge transport material and metal oxide particles of the present invention in combination with the charge transport layer constituting the surface layer, the organic photosensitive material which satisfies both high speed characteristics and active gas resistance and prevents the occurrence of voids. You can get a body. The content of the charge transport material in the charge transport layer is preferably 50 to 200 parts by mass with respect to 100 parts by mass of the binder resin.

  The total thickness of the charge transport layer is preferably 10 to 30 μm.

  When preparing the charge transport layer according to the present invention, a dispersion of the charge transport layer is prepared. As a solvent for the charge transport layer dispersion, a non-halogen solvent having a small environmental load is used. Non-halogen solvents include acetone, methyl ethyl ketone, methyl isopropyl ketone, cyclohexanone, benzene, toluene, xylene, tetrahydrofuran, dioxolane, dioxane, methanol, ethanol, butanol, isopropanol, ethyl acetate, butyl acetate, dimethyl sulfoxide, methyl cellosolve, etc. Can be mentioned.

  The solvent for the charge transport layer dispersion is not limited to these, but toluene, tetrahydrofuran (THF), dioxolane and the like are particularly preferably used. These solvents may be used alone or as a mixed solvent of two or more.

  As a coating processing method for producing the organic photoreceptor of the present invention, a coating processing method such as dip coating, spray coating, circular amount regulation type coating or the like is used, but the upper layer side coating processing of the photosensitive layer is a lower layer film. In order to achieve a uniform coating process, it is preferable to use a coating process method such as spray coating or circular amount regulation type (a circular slide hopper type is a typical example). The spray coating is described in detail in, for example, JP-A-3-90250 and JP-A-3-269238, and the circular amount-regulating coating is described in detail in, for example, JP-A-58-189061. Yes.

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

  An image forming apparatus 1 shown in FIG. 2 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 toner, developing means (developing process) 23, transfer conveying belt device 45 as a transferring means (transfer process), cleaning device (cleaning process) 26 for the photosensitive member 21, and light neutralizing means (light slow charge). PCL (precharge lamp) 27 as a process is 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. As the photosensitive member 21, the organic photosensitive member according to the present invention is used, and the photosensitive member 21 is driven and rotated in the clockwise direction shown in the drawing.

  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 as the writing means uses a laser diode (not shown) as a light source, and the optical path is bent by the reflection mirror 32 via the rotating polygon mirror 31, the fθ lens 34, and the cylindrical lens 35, and main scanning is performed. 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 apparatus of the present invention, a semiconductor laser or a light emitting diode can be used as an image exposure light source when an electrostatic latent image is formed on a photoreceptor. By using these image exposure light sources, the exposure dot diameter in the writing direction is narrowed to 10 to 80 μm, and digital exposure is performed on the organic photoreceptor, so that it is 400 dpi (dpi: the number of dots per 2.54 cm) or more. A high-resolution electrophotographic image of 2500 dpi can be obtained.

The exposure dot diameter refers to the length of the exposure beam (Ld: measured at the maximum position) along the main scanning direction in a region where the intensity of the exposure beam is 1 / e ² or more of the peak intensity.

The light beams used have a solid scanner such as the scanning optical system and LED using a semiconductor laser, there is a Gaussian distribution and Lorentz distribution, etc. also the light intensity distribution is in each 1 / e ² or more regions of peak intensity The exposure dot diameter according to the present invention is used.

  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, it is preferable to use a polymerized toner as a developer used in the developing means. By using a polymer toner having a uniform shape and particle size distribution in combination with the organic photoreceptor according to the present invention, an electrophotographic image with better sharpness can be obtained.

  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.

  FIG. 3 is a cross-sectional configuration diagram of a color image forming apparatus showing an embodiment of the present invention.

  This color image forming apparatus is called a tandem type color image forming apparatus, and includes four sets of image forming units (image forming units) 10Y, 10M, 10C, and 10Bk, an endless belt-shaped intermediate transfer body unit 7, and a feeding unit. It comprises a paper conveying means 21 and a fixing means 24. A document image reading device SC is disposed on the upper part of the main body A of the image forming apparatus.

  The image forming unit 10Y that forms a yellow image includes a charging unit (charging step) 2Y, an exposure unit (exposure step) 3Y, and a developing unit disposed around a drum-shaped photoconductor 1Y as a first image carrier. A unit (developing step) 4Y, a primary transfer roller 5Y as a primary transfer unit (primary transfer step), and a cleaning unit 6Y. An image forming unit 10M that forms a magenta image includes a drum-shaped photosensitive member 1M as a first image carrier, a charging unit 2M, an exposure unit 3M, a developing unit 4M, a primary transfer roller 5M as a primary transfer unit, It has a cleaning means 6M. An image forming unit 10C for forming a cyan image includes a drum-shaped photoreceptor 1C as a first image carrier, a charging unit 2C, an exposure unit 3C, a developing unit 4C, and a primary transfer roller 5C as a primary transfer unit. It has cleaning means 6C. The image forming unit 10Bk that forms a black image includes a drum-shaped photoreceptor 1Bk as a first image carrier, a charging unit 2Bk, an exposure unit 3Bk, a developing unit 4Bk, a primary transfer roller 5Bk as a primary transfer unit, and a cleaning unit. 6Bk.

  The four sets of image forming units 10Y, 10M, 10C, and 10Bk include charging means 2Y, 2M, 2C, and 2Bk that rotate around the photosensitive drums 1Y, 1M, 1C, and 1Bk, and image exposure means 3Y, 3M, 3C and 3Bk, rotating developing means 4Y, 4M, 4C and 4Bk, and cleaning means 5Y, 5M, 5C and 5Bk for cleaning the photosensitive drums 1Y, 1M, 1C and 1Bk.

  The image forming units 10Y, 10M, 10C, and 10Bk have the same configuration except that the colors of toner images formed on the photoreceptors 1Y, 1M, 1C, and 1Bk are different, and the image forming unit 10Y is taken as an example in detail. explain.

  The image forming unit 10Y has a charging unit 2Y (hereinafter simply referred to as a charging unit 2Y or a charger 2Y), an exposure unit 3Y, a developing unit 4Y, and a cleaning unit 5Y (around a photosensitive drum 1Y as an image forming body). Hereinafter, the cleaning means 5Y or the cleaning blade 5Y) is simply disposed, and a yellow (Y) toner image is formed on the photosensitive drum 1Y. In the present embodiment, in the image forming unit 10Y, at least the photosensitive drum 1Y, the charging unit 2Y, the developing unit 4Y, and the cleaning unit 5Y are provided so as to be integrated.

  The charging unit 2Y is a unit that applies a uniform potential to the photosensitive drum 1Y. In the present embodiment, a corona discharge type charger 2Y is used for the photosensitive drum 1Y.

  The image exposure means 3Y performs exposure based on the image signal (yellow) on the photosensitive drum 1Y given a uniform potential by the charger 2Y, and forms an electrostatic latent image corresponding to the yellow image. As the exposure means 3Y, the exposure means 3Y includes an LED in which light emitting elements are arranged in an array in the axial direction of the photosensitive drum 1Y and an imaging element (trade name; Selfoc lens), or A laser optical system or the like is used.

  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 (image forming unit), and this image forming unit is connected to the apparatus main body. It may be configured to be detachable. In addition, at least one of a charging device, an image exposure device, a developing device, a transfer or separation device, and a cleaning device is integrally supported together with a photosensitive member to form a process cartridge (image forming unit), which is detachable from the apparatus main body. A single image forming unit may be detachable using guide means such as a rail of the apparatus main body.

  The endless belt-like intermediate transfer body unit 7 includes an endless belt-like intermediate transfer body 70 as a second image carrier having a semiconductive endless belt shape that is wound around a plurality of rollers and is rotatably supported.

  Each color image formed by the image forming units 10Y, 10M, 10C, and 10Bk is sequentially transferred onto a rotating endless belt-shaped intermediate transfer body 70 by primary transfer rollers 5Y, 5M, 5C, and 5Bk as primary transfer means. Thus, a synthesized color image is formed. A transfer material P as a transfer material (a support for carrying a fixed final image: for example, plain paper, a transparent sheet, etc.) housed in the paper feed cassette 20 is fed by a paper feed means 21 and a plurality of intermediates. After passing through rollers 22A, 22B, 22C, 22D and registration roller 23, they are conveyed to a secondary transfer roller 5b as a secondary transfer means, and are secondarily transferred onto a transfer material P to transfer a color image all at once. The transfer material P onto which the color image has been transferred is subjected to fixing processing by the fixing unit 24, is sandwiched between paper discharge rollers 25, and is placed on a paper discharge tray 26 outside the apparatus. Here, a transfer support for a toner image formed on a photosensitive member such as an intermediate transfer member or a transfer material is collectively referred to as a transfer medium.

  On the other hand, after the color image is transferred to the transfer material P by the secondary transfer roller 5b as the secondary transfer means, the residual toner is removed by the cleaning means 6b from the endless belt-shaped intermediate transfer body 70 in which the transfer material P is separated by curvature. The

  During the image forming process, the primary transfer roller 5Bk is always in contact with the photoreceptor 1Bk. The other primary transfer rollers 5Y, 5M, and 5C are in contact with the corresponding photoreceptors 1Y, 1M, and 1C, respectively, only during color image formation.

  The secondary transfer roller 5b contacts the endless belt-shaped intermediate transfer body 70 only when the transfer material P passes through the secondary transfer roller 5b.

  Further, the housing 8 can be pulled out from the apparatus main body A through the support rails 82L and 82R.

  The housing 8 includes image forming units 10Y, 10M, 10C, and 10Bk and an endless belt-shaped intermediate transfer body unit 7.

  The image forming units 10Y, 10M, 10C, and 10Bk are arranged in tandem in the vertical direction. An endless belt-shaped intermediate transfer body unit 7 is disposed on the left side of the photoreceptors 1Y, 1M, 1C, and 1Bk in the drawing. The endless belt-shaped intermediate transfer body unit 7 includes an endless belt-shaped intermediate transfer body 70 that can be rotated by winding rollers 71, 72, 73, 74, primary transfer rollers 5Y, 5M, 5C, 5Bk, and cleaning means 6b. Consists of.

  Next, FIG. 4 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. FIG. The belt-shaped intermediate transfer body 70 uses an elastic body having a medium resistance.

  Reference numeral 1 denotes a rotary drum type photoconductor that is repeatedly used as an image forming body, and is rotationally driven in a counterclockwise direction indicated by an arrow at a predetermined peripheral speed.

  In the rotation process, the photoreceptor 1 is uniformly charged to a predetermined polarity and potential by a charging means (charging process) 2, and then time-series electric digital of image information by an image exposure means (image exposure process) 3 (not shown). An electrostatic latent image corresponding to the yellow (Y) color component image (color information) of the target color image is formed by receiving image exposure by scanning exposure light or the like by a laser beam modulated in accordance with the pixel signal. The

  Then, the electrostatic latent image is developed with yellow toner as the first color by yellow (Y) developing means: developing step (yellow color developing device) 4Y. At this time, the second to fourth developing means (magenta developer, cyan developer, black developer) 4M, 4C, and 4Bk are turned off and do not act on the photosensitive member 1. 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 driven to rotate in the clockwise direction at the same peripheral speed as the photosensitive member 1.

  The yellow toner image of the first color formed and supported on the photoreceptor 1 is applied to the intermediate transfer body 70 from the primary transfer roller 5a 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 photoreceptor 1 after the transfer of the first color yellow toner image corresponding to the intermediate transfer body 70 is cleaned by the cleaning device 6a.

  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 5b 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 1 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 1 to the intermediate transfer member 70, the secondary transfer roller 5b and the intermediate transfer member cleaning means 6b can be separated from the intermediate transfer member 70. is there.

  When the superimposed color toner image transferred onto the belt-shaped intermediate transfer member 70 is transferred to the transfer material P, which is the second image carrier, the secondary transfer roller 5b is brought into contact with the belt of the intermediate transfer member 70. At the same time, the transfer material P is fed from the pair of paper registration rollers 23 through the transfer paper guide to the belt of the intermediate transfer body 70 to the contact nip with the secondary transfer roller 5b at a predetermined timing. A secondary transfer bias is applied to the secondary transfer roller 5b 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 24 and heated and fixed.

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

  The organic photoreceptor of the present invention is preferably applied to an image forming apparatus having a process speed (linear speed of the photoreceptor during image formation) of 400 mm / sec or more. When the process speed is 400 mm / sec or more, the photosensitive member is repeatedly rotated at a high speed, so that the characteristic deterioration of the photosensitive member is liable to proceed and the image density is likely to be lowered and fogging. The combined use of physical particles can solve these problems, and at the same time, can prevent deterioration of the active gas resistance that is likely to occur when a high-speed charge transport material (CTM) is used, and can prevent image blurring. it can.

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

Production of Photoreceptor 1 Photoreceptor 1 was produced as follows.

Intermediate layer The following intermediate layer coating solution is applied by dip coating on a washed cylindrical aluminum substrate having a diameter of 25 mm (10 points surface roughness Rz: 0.81 μm processed by cutting), and 120 ° C. for 30 minutes. And an intermediate layer having a dry film thickness of 5 μm was formed.

  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: (Polyamide) 1 part Rutile titanium oxide (primary particle size 35 nm; titanium oxide pigment prepared by surface treatment with dimethylpolysiloxane having a hydroxyl group at the terminal and having a hydrophobic degree of 33) 5.6 parts 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: CGL
Charge generation material (CGM): oxytitanyl phthalocyanine (a titanyl phthalosine pigment having a maximum diffraction peak at a Bragg angle (2θ ± 0.2 °) of 27.3 ° in an X-ray diffraction spectrum by Cu-Kα characteristic X-ray) 24 parts polyvinyl butyral resin “S-LEC BL-1” (manufactured by Sekisui Chemical Co., Ltd.) 12 parts 2-butanone / cyclohexanone = 4/1 (v / v) 300 parts The above composition is mixed, dispersed using a sand mill, and charged. A generation layer coating solution was prepared. This coating solution was applied by a dip coating method to form a charge generation layer having a dry film thickness of 0.5 μm on the intermediate layer.

Charge transport layer 1 (CTL1)
Charge transport material (CTM-1) 225 parts Polycarbonate (Z300: Mitsubishi Gas Chemical Co., Ltd.) 300 parts Antioxidant (Irganox 1010: Nihon Ciba Geigy Co., Ltd.) 6 parts Dichloromethane 2000 parts Silicon oil (KF-54: Shin-Etsu Chemical Co., Ltd.) One part was mixed and dissolved to prepare a charge transport layer coating solution 1. This coating solution was applied onto the charge generation layer by a dip coating method and dried at 110 ° C. for 70 minutes to form a charge transport layer 1 having a dry film thickness of 18.0 μm.

Charge transport layer 2 (CTL2)
Metal oxide particles No. 1: Alumina particles (primary treatment: dimethyldichlorosilane, secondary treatment: alumina with an average primary particle size of 0.12 μm surface-treated with hexamethyldisilazane: hydrophobization degree 66, hydrophobization degree distribution value 15) 60 parts Charge Transport material (CTM-1) 150 parts Polycarbonate (Z300: manufactured by Mitsubishi Gas Chemical) 300 parts Exemplary compound AO1-1 12 parts THF: Tetrahydrofuran 2800 parts Silicon oil (KF-54: manufactured by Shin-Etsu Chemical Co., Ltd.) 4 parts are mixed. The charge transport layer coating solution 2 was prepared by dispersing and dissolving. This coating solution is applied onto the charge transport layer 1 with a circular slide hopper coater, dried at 110 ° C. for 70 minutes to form a charge transport layer 2 having a dry film thickness of 2.0 μm, and the photoreceptor 1 is formed. Produced. The residual solvent in all layers of the photoreceptor 1 was 3600 ppm.

Production of Photoreceptors 2 to 10 Photoreceptor 1 except that the types of the charge transport materials of charge transport layers 1 and 2 and the metal oxide particles of charge transport layer 2 were changed as shown in Table 1 in the production of photoreceptor 1. Photoconductors 2 to 10 were produced in the same manner as described above. However, CTM-R1 and CTM-R2 represent the following compounds.

  In Table 1, the details of the metal oxide particles are shown in Table 2 below. However, * mark and ** mark in Table 2 indicate the following surface treatment agents.

Silazane; Hexamethyldisilazane Silicone oil; Methyl hydrogen silicone oil In addition, the hydrophobization degree and the hydrophobization degree distribution value of the metal oxide particles used in the photoreceptors 1 to 10 are 20 ° C. after the surface treatment of the metal oxide particles. It is a value measured by the measurement method described above after storage for 3 days in a 60% RH environment (3 days after NN).

<< Evaluation 1 >>
<Live-action evaluation>
The above photoreceptor was mounted on a commercially available full color multifunction device 8050 (manufactured by Konica Minolta Business Technologies Co., Ltd.) having the structure shown in FIG. 3 and color images were evaluated.

Evaluation condition Photoconductor linear velocity: 220 mm / sec
《Image evaluation》
Each photoconductor is attached to the above-mentioned full-color multifunction device 8050 remodeled machine (modified so that each photoconductor can be mounted), and A4 paper, 10,000 character images, white in an environment of normal temperature and humidity (20 ° C, 50% RH) An original image having a solid image, a black solid image, and a halftone image was copied, and the copied image was taken out at the start and every 1,000 copies, and the following image evaluation was performed.

Other conditions for image formation Process speed: 220 mm / sec
Developer: A two-component developer (both Y, M, C, and Bk) containing a carrier and a toner was used.

  Photoconductor cleaning device: A rubber elastic cleaning blade was used under a contact condition of (linear load: 18 (N / m)).

  Intermediate transfer member cleaning device: A rubber elastic cleaning blade was used.

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. The measurement was performed on a solid black image portion after 200,000 copies.

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)
Reproducibility of toner image on photoreceptor The toner image on the photoreceptor was transferred to a transparent adhesive sheet for evaluation.

A: The occurrence of voids is very small, and the dot image is clearly reproduced (good)
○: There is a small void, but the dot image is reproduced (practical)
×: Many voids occur and the shape of the dot image is broken (unusable)
Reproducibility of toner image on intermediate transfer member The toner image on the intermediate transfer member was transferred to a transparent adhesive sheet, and the transfer image was evaluated.

A: The occurrence of voids is very small, and the dot image is clearly reproduced (good)
○: There is a small void, but the dot image is reproduced (practical)
×: Many voids occur and the shape of the dot image is broken (unusable)
The reproducibility of the toner on the intermediate transfer member is an evaluation substantially corresponding to the reproducibility of the toner image on the transfer paper of the final image.

(Image blur: Active gas resistance)
The above-mentioned full-color MFP 8050 modified machine is installed in a low-temperature, low-humidity (10 ° C, 10% RH) environment, and after continuous copying of 1000 sheets, it is stopped for 20 minutes, and then a halftone image is copied and generated just below the strip electrode The occurrence of blurred image was observed and evaluated according to the following evaluation criteria.

A: No blurring is observed in the halftone image (good)
○: Image unevenness having a density difference of less than 0.05 occurs in the halftone image, but the density difference is not so noticeable in the halftone image. (Practical problem level)
X: An image blur having a density difference of 0.05 or more occurs in the halftone image, and the density difference is clear in the halftone image. (There are practical problems)

  From the results shown in Table 3, the photoconductors (No. 1 to 5, 8 and 9) containing the charge transport material and metal oxide particles according to the present invention are all in the image density, the toner image on the photoconductor. The reproducibility and reproducibility of the toner image on the intermediate transfer member are good, the effect of preventing image blurring is good, and a good electrophotographic image is obtained for each evaluation. On the other hand, the photoconductor 6 using the charge transport material CTMR-1 other than the present invention has image blur, and the photoconductor 7 using the charge transport material CTMR-2 has an image density and a toner image on the intermediate transfer body. The reproducibility of has deteriorated. In addition, the reproducibility of the toner image on the intermediate transfer member is deteriorated in the photoreceptor 10 that does not contain metal oxide particles.

<< Evaluation 2 >>
The photoreceptor No. 2 and no. 4 was mounted on a commercially available color printer magiccolor 2300 (manufactured by Konica Minolta Business Technologies, Inc.) having the configuration of FIG. As a result, all the photoconductors have good image density, reproducibility of the toner image on the photoconductor, and reproducibility of the toner image on the intermediate transfer member, and also have a good image blur prevention effect, and are good for each evaluation. Had acquired a good electrophotographic image.

<< Evaluation 3 >>
Next, photoconductors 21 to 25 were prepared in the same manner except that the cylindrical aluminum substrate of the photoconductors 1 to 5 was changed from a diameter of 25 mm to 100 mm.

  The digital photocopier Konica “Sitos” 7085 (manufactured by Konica Minolta Business Technologies Co., Ltd.), a scorotron charger, a semiconductor laser image exposure device, a reversal developing means, and the photoconductors 21 to 25 basically having the structure shown in FIG. And a copying experiment was conducted.

《Image evaluation》
Attach each photoconductor to the above digital copier and copy the original image with A4 paper, 1 million text images, white solid image, black solid image in high temperature and high humidity (30 ° C, 80% RH) environment, The copied image was taken out at the start and every 100,000 copies, and the following image evaluation was performed.

Other conditions for image formation Process speed: 420 mm / sec
Charging conditions: A scorotron band electrode was used as the band electrode, and the grit voltage of the band electrode was set to 650V.

  Developer: A two-component developer containing carrier and toner was used.

(Potential stability)
At the start and every 100,000 copies, a potential sensor was installed at the position of the developing unit for the above-mentioned digital copy image, and the potential holding property and residual potential of the photosensitive member were evaluated.

  A: From the start to 1 million sheets, the change in the charging potential is in the range of less than 650 ± 50V, the stability of the charging potential is good, and the increase in the residual potential is also good at less than 50V.

○: From the start to 1 million sheets, the change in the charging potential is within a range of 650 ± 100 V, and the increase in the residual potential is 50 V or more and 100 V or less. (There is practicality)
X: From the start to 1 million sheets, the change in charging potential is larger than 650 ± 100V, and the increase in residual potential is also larger than 100V. (There is a problem with practicality)
(Image density)
A black solid image of a copied image was measured using a Macbeth RD-918. Measured with relative reflection density with paper reflection density set to “0” (image density)
A: From the start to 1 million sheets, the black solid image density is 1.3 or higher and the image density is high.

  ○: From the start to 1 million sheets, the black solid image density is 1.0 or more, which is a practically sufficient image density.

Δ: Black solid image density of 0.7 to less than 1.0 occurred between 1 million sheets from the start (re-examination required for practical use)
×: Black solid image density of less than 0.7 occurs between 1 million sheets from the start (There is a problem in practical use)
(Fog)
Using a Macbeth reflection densitometer “RD-918”, the density of copy paper (white paper) is measured at 20 locations at absolute image density, and the average value is defined as the white paper density. Next, 20 white solid images of the copied image were similarly measured at the absolute image density, and the value obtained by subtracting the white paper density from the average density was evaluated as the fog density.

A: From the start to 1 million sheets, white solid image density is 0.005 or less (good)
○: From the start to 1 million sheets, the white solid image density is 0.01 or less (a level that is not a problem for practical use)
×: fogging with a solid white image density greater than 0.01 between the start and 1 million sheets (obviously, there is a practical problem)
(Image blur: Active gas resistance)
The above digital copying machine Konica “Sitos” 7085 is installed in an environment of low temperature and low humidity (10 ° C., 10% RH). After continuous copying of 1000 sheets, it is stopped for 20 minutes, and then a halftone image is copied and directly under the band electrode. The occurrence of image blur was observed and evaluated according to the following evaluation criteria.

A: No blurring is observed in the halftone image (good)
○: Image unevenness having a density difference of less than 0.15 occurs in the halftone image, but the density difference is not so noticeable in the halftone image. (Practical problem level)
X: An image blur having a density difference of 0.15 or more occurs in the halftone image, and the density difference is clear in the halftone image. (There are practical problems)

  As is apparent from Table 4, the photoreceptors 21 to 25 containing the charge transport layer and the metal oxide particles satisfying the conditions of the present invention in the charge transport layer have good potential stability. Both evaluations of fog and fog gave good results. Further, the evaluation of the active gas was good, and as a result, the occurrence of image blur was prevented and a good electrophotographic image could be formed.

It is a figure which shows a hydrophobization degree distribution curve. 1 is a schematic view in which functions of an image forming apparatus of the present invention are incorporated. 1 is a cross-sectional configuration diagram of a color image forming apparatus showing an embodiment of the present invention. 1 is a cross-sectional view of a color image forming apparatus using an organic photoreceptor of the present invention.

Explanation of symbols

10Y, 10M, 10C, 10Bk Image forming unit 1Y, 1M, 1C, 1Bk Photoconductor 2Y, 2M, 2C, 2Bk Charging unit 3Y, 3M, 3C, 3Bk Exposure unit 4Y, 4M, 4C, 4Bk Developing unit

Claims (13)

In an organic photoreceptor for use in an image forming method in which a uniform charge is imparted on an organic photoreceptor in a charging process, an electrostatic latent image is formed in an image exposure process, and the electrostatic latent image is visualized as a toner image in a development process. A photosensitive layer containing at least a charge generation material and a charge transport material on a conductive substrate, the photosensitive layer having a triarylamine group and indirectly linked to the N atom of the triarylamine group; In addition, on the farthest carbocyclic group, it has at least one carbon atom having a HOMO electron density distribution value of 0.009 or more determined by semiempirical molecular orbital calculation using the AM1 parameter, An organophotoreceptor comprising a charge transport material and metal oxide particles of a compound having a dipole moment determined by the semi-empirical molecular orbital calculation of 0.7 debye or less. A charging process for charging the organic photoreceptor, a latent image forming process for forming an electrostatic latent image on the charged organic photoreceptor, a developing process for visualizing the electrostatic latent image into a toner image, and the visualized image In an organic photoconductor used in an image forming method, the method includes a primary transfer step of transferring a toner image from an organic photoconductor onto an intermediate transfer member, and a secondary transfer step of transferring a toner image on the intermediate transfer member to a transfer material. A photosensitive layer containing at least a charge generating material and a charge transporting material on the conductive substrate, the photosensitive layer having a triarylamine group and indirectly linked to the N atom of the triarylamine group, On the farthest carbocyclic group, it has at least one carbon atom having a HOMO electron density distribution value of 0.009 or more determined by semiempirical molecular orbital calculation using AM1 parameter, and Semi-empirical Organic photoreceptor, wherein a dipole moment found by the trajectory calculation contains a charge transporting material and the metal oxide particles of 0.7 Debye following compounds. The organophotoreceptor according to claim 1, wherein the carbocyclic group is a phenyl group. 4. The photosensitive layer according to claim 1, wherein the photosensitive layer has a structure in which a charge generation layer containing a charge generation material and a charge transport layer containing a charge transport material laminated thereon are laminated. 2. The organophotoreceptor according to item 1. The organophotoreceptor according to claim 1, wherein the charge transport material has an ionization potential of 7.6 to 7.9 eV. 6. The organophotoreceptor according to claim 1, wherein the number average primary particle size (Dp) of the metal oxide particles is in a range of 0.010 [mu] m <Dp <1.00 [mu] m. 7. The organophotoreceptor according to claim 1, wherein the metal oxide particles are at least one selected from titanium oxide, zinc oxide, alumina, and silica. The organophotoreceptor according to claim 1, wherein the charge transport material and metal oxide particles are contained in a surface layer. In an image forming method, a uniform charge is imparted on an organic photoreceptor in a charging step, an electrostatic latent image is formed in an image exposure step, and the electrostatic latent image is visualized as a toner image in a development step. Has a photosensitive layer containing at least a charge generating material and a charge transporting material on a conductive substrate, the photosensitive layer has a triarylamine group and is indirectly linked to the N atom of the triarylamine group, In addition, on the farthest carbocyclic group, it has at least one carbon atom having a HOMO electron density distribution value of 0.009 or more determined by semiempirical molecular orbital calculation using the AM1 parameter, An image forming method comprising: a compound having a dipole moment obtained by the semi-empirical molecular orbital calculation of 0.7 debye or less and a charge transport material and metal oxide particles. A charging process for charging the organic photoreceptor, a latent image forming process for forming an electrostatic latent image on the charged organic photoreceptor, a developing process for visualizing the electrostatic latent image into a toner image, and the visualized image In an image forming method comprising a primary transfer step of transferring a toner image from an organic photoreceptor onto an intermediate transfer member and a secondary transfer step of transferring the toner image on the intermediate transfer member onto a transfer material, the organic photoreceptor is conductive A photosensitive layer containing at least a charge generation material and a charge transport material on the substrate, the photosensitive layer having a triarylamine group and indirectly linked to an N atom of the triarylamine group, A carbocyclic group present at a distance has at least one carbon atom having a HOMO electron density distribution value of 0.009 or more determined by semiempirical molecular orbital calculation using the AM1 parameter; Empirical molecular orbital meter The image forming method of dipole moment obtained is characterized by containing the charge-transporting material and the metal oxide particles of the following compounds 0.7 Debye by. An organic photoreceptor, a charger for uniformly charging the organic photoreceptor, an image exposure unit for forming an electrostatic latent image on the organic photoreceptor, and a developer for developing the electrostatic latent image into a toner image In the image forming apparatus, the organic photoreceptor has a photosensitive layer containing at least a charge generation material and a charge transport material on a conductive substrate, the photosensitive layer has a triarylamine group, and the triarylamine group The value of the HOMO electron density distribution obtained by the semi-empirical molecular orbital calculation using the AM1 parameter is 0.009 or more on the carbocyclic group that is indirectly linked to the N atom of It contains a charge transport material and metal oxide particles of a compound having at least one carbon atom and having a dipole moment determined by the semi-empirical molecular orbital calculation of 0.7 debye or less. Picture Forming apparatus. The image forming apparatus according to claim 11, wherein a process speed is 400 mm / sec or more. An organic photoreceptor, a charger for uniformly charging the organic photoreceptor, an image exposure unit for forming an electrostatic latent image on the organic photoreceptor, and a developer for developing the electrostatic latent image into a toner image A process cartridge for use in an image forming apparatus having a photosensitive layer containing at least a charge generating substance and a charge transporting substance on a conductive substrate, the photosensitive layer having a triarylamine group, and the triarylamine group The value of the HOMO electron density distribution obtained by the semi-empirical molecular orbital calculation using the AM1 parameter is 0.009 or more on the carbocyclic group that is indirectly linked to the N atom of It contains a charge transport material and metal oxide particles of a compound having at least one carbon atom and having a dipole moment determined by the semi-empirical molecular orbital calculation of 0.7 debye or less. The photoconductor and at least one of charging means, latent image forming means, developing means, transfer means, charge eliminating means, and cleaning means are integrally supported, and can be detachably attached to the image forming apparatus main body. Feature process cartridge.

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