JP2006330251A - Organophotoreceptor, process cartridge, image forming method and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reproduce a dot latent image on an organophotoreceptor formed with an image exposure light source such as a semiconductor laser as a toner image with high fineness on the organophotoreceptor, and to faithfully transfer the reproduced toner image onto a transfer medium. <P>SOLUTION: The organophotoreceptor has a photosensitive layer on a conductive support, wherein a surface layer of the organophotoreceptor contains an A-B block copolymer or a B-A-B block copolymer (a block copolymer of a component A and a component B) comprising the following polycarbonate component and polysiloxane component, and has a sea-island structure forming domains in which the polysiloxane components assemble. The component A: a polycarbonate component, the component B: a polysiloxane component. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an organic photoreceptor used for electrophotographic image formation, a process cartridge using the organic photoreceptor, an image forming method, and an image forming apparatus. More specifically, the present invention relates to electrophotography used in the fields of copying machines and printers. The present invention relates to an organic photoreceptor used for image formation of a system, a process cartridge using the organic photoreceptor, an image forming method, and an image forming apparatus.

  In recent years, there are increasing opportunities to use electrophotographic copying machines and printers in the fields of printing and color printing. In the fields of printing and color printing, there is a strong tendency to demand high-quality digital monochrome images or color images. In response to such demands, it has been proposed to reduce the exposure beam of the exposure light source and form a high-definition digital image (Patent Document 1). However, even if the exposure beam of the semiconductor laser or the like is narrowed down to form a dot latent image by fine dot exposure on the organic photoreceptor, the finally obtained electrophotographic image achieves sufficient high image quality. The current situation is that we have not obtained it.

  One of the causes is that even when a fine dot latent image is formed on an organic photoreceptor using semiconductor laser light or the like, the dot latent image cannot be accurately reproduced as a toner image. It is done. That is, the surface characteristics of the organophotoreceptor are poor in micro units, and the dot latent image formed by a semiconductor laser or the like is reproduced as a toner image smaller than the size of the latent image, or reproduced as a larger toner image. The toner image formed on the organic photoreceptor is not sufficiently transferred to a transfer medium (such as a transfer material such as paper or an intermediate transfer member). In addition, problems such as the occurrence of transfer omission (hereinafter simply referred to as omission) and a decrease in image density are likely to occur.

As a method for improving the surface characteristics of the organic photoreceptor, an organic photoreceptor in which fluororesin fine particles are contained on the surface of the organic photoreceptor has been proposed (Patent Document 2). Organic photoreceptors containing these fluororesin fine particles prevent toner filming and the like and have a characteristic that the surface is not easily contaminated. However, the fluororesin fine particles are dispersed in a binder resin in a micro size. The fluororesin fine particles and the binder resin are separated at a micro level, and as a result, image blur is likely to occur. Further, the surface layer of the fluorine-containing resin fine particles has insufficient wear resistance, and the surface layer is easily scratched. For this reason, there is a problem that the halftone image is easily scratched.
Japanese Patent Laid-Open No. 2001-255585 JP-A-8-328287

  The present invention has been made to solve the above problems, and an object of the present invention is to increase a dot latent image on an organic photoreceptor formed by an image exposure light source such as a semiconductor laser on the organic photoreceptor. It is to provide an organic photoreceptor that can be finely reproduced as a toner image and faithfully transfer the reproduced toner image to a transfer medium, improving transferability of the toner image on the organic photoreceptor to the transfer medium, The present invention provides an organic photoreceptor that prevents the occurrence of voids and dot image deterioration and that has improved surface layer cleaning characteristics. A process cartridge, an image forming method, and an image forming apparatus using the organic photoreceptor are provided. Is to provide.

  As a result of repeated investigations on the above problems, it is possible to form a dot latent image on an organic photoreceptor formed with an image exposure light source such as a semiconductor laser into a high-definition toner image and to form the high-definition toner. In order to transfer an image faithfully from an organic photoreceptor to a transfer medium and finally obtain an accurate toner image, the surface characteristics of the organic photoreceptor can be made into a uniform low surface energy state in micro units and can be cleaned. The present invention was completed by finding that it is necessary to develop an excellent surface layer technology.

That is, the present invention is achieved by having the following configuration.
(Claim 1)
In an organic photoreceptor having a photosensitive layer on a conductive support, an AB block copolymer or a B-A-B block copolymer (A) in which the surface layer of the organic photoreceptor has the following polycarbonate component and polysiloxane component: And an organic photoreceptor having a sea-island structure in which a domain in which the polysiloxane components are aggregated is formed.

Component A: Polycarbonate component Component B: Polysiloxane component (Claim 2)
2. The organic photoreceptor according to claim 1, wherein the polycarbonate component has a structure represented by the following general formula (1), and the polysiloxane component has a structure represented by the following general formula (2).

(In General Formula (1), Y ^{1 to} Y ⁸ are each independently a hydrogen atom, a saturated aliphatic hydrocarbon group having 1 to 10 carbon atoms, an unsaturated aliphatic hydrocarbon group having 3 to 10 carbon atoms, and a halogen atom. , A halogenated alkyl group, an alkoxyl group, an optionally substituted aromatic hydrocarbon group having 6 to 20 carbon atoms, X is the following divalent linking group;

And an aromatic ring, a single bond, a lactone, and fluorene, wherein R ^{1 to} R ⁷ are each independently a hydrogen atom, a saturated aliphatic hydrocarbon group having 1 to 10 carbon atoms that may have a substituent, and a substituent. An unsaturated aliphatic hydrocarbon group having 3 to 10 carbon atoms, a halogen, an alkoxyl group, and an aromatic hydrocarbon group having 6 to 20 carbon atoms that may have a substituent. , Z represents a substituted or unsubstituted aliphatic hydrocarbon group having 3 to 20 carbon atoms, a is an integer of 0 to 4; l is an integer of 1 to 6; m is an integer of 2 to 20 Show. )
(In the general formula (2), R ¹³ represents a divalent organic residue containing aliphatic and / or aromatic, and W represents a single bond, O, CO, COO, NH, NHCO, S, SO, SO _2. R ^{8 to} R ¹² are each independently a saturated aliphatic hydrocarbon group having 1 to 10 carbon atoms which may have a substituent or a carbon number having 6 to 20 which may have a substituent. The following aromatic hydrocarbon groups are shown, and n is an integer of 1 to 500.)
(Claim 3)
The organophotoreceptor according to claim 1, wherein the domain is a domain having a number average primary particle size of 1 to 100 nm.
(Claim 4)
The organophotoreceptor according to claim 1 or 2, wherein the surface layer has a domain density of 1 to 10,000 per 1 x 10 ⁴ nm ² .
(Claim 5)
The polycarbonate component of the A component has at least one repeating structure selected from the following polycarbonate (Z), polycarbonate (DM), and polycarbonate (A). The organophotoreceptor described.

(Claim 6)
The organophotoreceptor according to claim 1, wherein the number average molecular weight of the component A is 0.5 to 300,000.
(Claim 7)
The organic photoreceptor according to claim 1, wherein the organic photoreceptor has an intermediate layer, a charge generation layer, and a charge transport layer on a conductive support.
(Claim 8)
An organic photoreceptor, charging means for charging the organic photoreceptor, latent image forming means for forming an electrostatic latent image on the charged organic photoreceptor, developing means for developing the electrostatic latent image into a toner image, Transfer means for transferring the visualized toner image from the organic photoreceptor onto the transfer medium, charge eliminating means for removing the charge remaining on the organic photoreceptor after the transfer of the toner image, and residual on the organic photoreceptor after the transfer In a process cartridge used in an image forming apparatus having a cleaning means for removing toner to be removed, the surface layer of the organophotoreceptor has an AB block copolymer or BAB block copolymer having the following polycarbonate component and polysiloxane component. An organic photoconductor having a sea-island structure containing a polymer (block copolymer of component A and component B) and forming a domain in which the polysiloxane components are aggregated, a charging means, and a latent image Forming means, a developing means, a transfer medium, at least one means discharging means and the cleaning means are integrally supported, the process cartridge, which is a detachably mounted to the image forming apparatus main body.

Component A: Polycarbonate component Component B: Polysiloxane component (Claim 9)
An organic photoreceptor, charging means for charging the organic photoreceptor, latent image forming means for forming an electrostatic latent image on the charged organic photoreceptor, developing means for developing the electrostatic latent image into a toner image, A transfer medium for transferring the visualized toner image from the organic photoreceptor onto the transfer medium, a charge eliminating means for removing the charge on the organic photoreceptor after the transfer, and a residual toner on the organic photoreceptor after the transfer are removed. In the image forming method having a cleaning means, the surface layer of the organophotoreceptor has an AB block copolymer or a B-A-B block copolymer (A component and B component) having the following polycarbonate component and polysiloxane component: An image forming method using an organic photoreceptor having a sea-island structure containing a block copolymer) and forming a domain in which the polysiloxane components are aggregated.

Component A: Polycarbonate component Component B: Polysiloxane component (Claim 10)
An organic photoreceptor, charging means for charging the organic photoreceptor, latent image forming means for forming an electrostatic latent image on the charged organic photoreceptor, developing means for developing the electrostatic latent image into a toner image, A transfer medium for transferring the visualized toner image from the organic photoreceptor onto the transfer medium, a charge eliminating means for removing the charge on the organic photoreceptor after the transfer, and a residual toner on the organic photoreceptor after the transfer are removed. In the image forming apparatus having a cleaning means, the surface layer of the organophotoreceptor has an AB block copolymer or a B-A-B block copolymer (A component and B component) having the following polycarbonate component and polysiloxane component: An image forming apparatus using an organic photoreceptor having a sea-island structure containing a block copolymer) and forming a domain in which the polysiloxane components are aggregated.

A component: Polycarbonate component B component: Polysiloxane component

  By using the organic photoreceptor and process cartridge, image forming method, and image forming apparatus of the present invention, a dot latent image formed by using a semiconductor laser or the like can be formed into a high-definition dot image, and the photoreceptor. Therefore, it is possible to improve the transferability of toner from the toner to the transfer medium, to prevent voids and dot image deterioration, and to provide an electrophotographic image with improved cleaning properties.

  The organophotoreceptor of the present invention is an organophotoreceptor having a photosensitive layer on a conductive support, wherein the surface layer of the organophotoreceptor has the following polycarbonate component and polysiloxane component: AB block copolymer or BA It has a sea-island structure containing a -B block copolymer (block copolymer of A component and B component) and forming a domain in which the polysiloxane components are aggregated.

Component A: Polycarbonate component Component B: Polysiloxane component The organophotoreceptor of the present invention has the above-described configuration, so that a latent dot image formed using a semiconductor laser or the like can be formed into a high-definition dot image. In addition, it is possible to improve the transferability of toner from the photosensitive member to the transfer medium, to prevent the hollowing out and the deterioration of the dot image, and to provide an electrophotographic image with improved cleaning properties.

  The organophotoreceptor of the present invention has both block components of a polysiloxane component (B) as a low surface energy component that aggregates with the polycarbonate component (A) constituting the matrix component to form a domain, as a binder resin for the surface layer. A block copolymer is used.

  Here, the polysiloxane components in the block copolymer are aggregated to form a domain. The polycarbonate of the block copolymer forms a matrix (sea region of sea-island structure) as a matrix component, and is formed from the matrix component. This shows a structure in which polysiloxane components of low surface energy components are assembled in a polycarbonate substrate to form domains, and the domains are dispersed in the surface layer.

  Here, the low surface energy component is a component capable of forming a low surface energy state, and a contact angle with respect to pure water (20 ° C.) of a film produced only with the low surface energy component is formed only with the matrix component. Compared to the contact angle of the membrane with pure water (20 ° C.), it exhibits higher characteristics, and it is more preferable that the contact angle is 1 ° or more higher.

  Here, a method for measuring the contact angle of the organic photoreceptor will be described.

Contact angle and contact angle variation measurement The contact angle of the surface of the photosensitive member is 23 ° C. and 50% using a fully automatic contact angle meter (CA-W roll special model: manufactured by Kyowa Interface Science Co., Ltd.). Measure under RH environment. The measurement is completed within 5 to 30 seconds after the dropping of the water droplet in order to achieve both the change in the measured value due to water evaporation and the stability of the measurement. The measurement is based on the θ / 2 method. The contact angle value does not change within the normal water droplet amount range, but in the case of a photosensitive drum, the measurement is from a direction perpendicular to the axial direction, and the deviation from the drum curvature is ignored. Set to 70 μl.
The measurement is based on the initial photoconductor when added to the layer of the photoconductor, or when the photoconductor is used for image formation from the outside and the surface energy reducing agent is sufficiently applied to the photoconductor surface. (After at least 1000 sheets of repeated image formation). Measurement points were measured at four locations, 90 ° in the circumferential direction, at three locations at the center and 5 cm from the left and right end portions of the cylindrical photoconductor, and the average value was determined as the contact angle of the present invention. And a value that is the largest or most negatively deviated from this average value is taken as the variation value.

  The polycarbonate component forming the matrix component is preferably a polycarbonate having the structure of the general formula (1), and the polysiloxane component is preferably a polysiloxane having the structure of the general formula (2).

  Further, as the polycarbonate component, a polycarbonate component having any one of the repeating structures a) to c) is more preferable.

  On the other hand, as the polysiloxane component of the low surface energy component, the portion of the repeating structure of the general formula (2) is more preferably a polysiloxane component such as dimethylpolysiloxane, diethylpolysiloxane, methylethylpolysiloxane, or methylphenylpolysiloxane. preferable.

  Moreover, the synthesis method of AB block copolymer or BAB block copolymer (block copolymer of A component and B component) which has a polycarbonate component and a polysiloxane component is a known block copolymerization method. It can be synthesized by using a synthesis method.

  That is, using an alkaline solution of a bisphenol compound such as 2,2-bis (4-hydroxy-3-methylphenyl) propane, a methylene chloride solution of a polycarbonate oligomer was prepared by a phosgene method. 2-Benzoyl-5- (3-polydimethylsiloxane propoxy) phenol and antioxidant 4-tert-butylphenol (PTBP) are mixed, and sodium hydroxide is added to have polydimethylsiloxane at the end of the polycarbonate. Block copolymers can be made.

  By the synthesis method as described above, a block copolymer having a matrix component and a low surface energy component according to the present invention can be obtained. Specific examples of block copolymers preferably used in the present invention are as follows. Give up.

  In Table 1, the mass ratio (%) of the low surface energy component indicates the mass ratio of the low surface energy component to the total mass of the block copolymer.

  In Table 1, polycarbonate (A), polycarbonate (DM), polycarbonate (Z), polycarbonate (A-DM) and polycarbonate (DM-Z) represent a polycarbonate having the following structure.

  In the surface layer according to the present invention, the polysiloxane component of the low surface energy component is aggregated in the process of forming the surface layer to form a domain having a number average primary particle size of 1 to 100 nm, and in a matrix formed of a polycarbonate component. It has a structure dispersed in. The domain diameter is preferably a number average primary particle diameter of 1 to 100 nm. If the thickness is less than 1 nm, the effect of improving the contact angle does not last long, and the surface improvement effect tends to decrease. On the other hand, when the thickness exceeds 100 nm, the surface layer cannot be formed in a low surface energy state in a microscopic state, the transferability of the toner image from the organic photoreceptor to the transfer medium becomes partially insufficient, and the voids are likely to occur. On the other hand, if the domain diameter exceeds 100 nm, the wear resistance during cleaning deteriorates, and scratches are likely to appear in the halftone image.

  The AB or BAB type block copolymer of the present invention preferably has a smaller molecular weight of the B component polysiloxane component than the molecular weight of the A component polycarbonate component. The polymerization degree of the component A is 0.5 to 300,000 in terms of number average molecular weight, and the number average molecular weight of the component B is preferably 200 to 20000, more preferably 500 to 15000.

  The number average molecular weights of the A and B components of the AB or BAB type block copolymer according to the present invention are calculated by measuring the molecular weight distribution measured by GPC.

  Here, as a method for measuring the molecular weight of the resin by GPC, 1 ml of THF is added to 0.5 to 5.0 mg (specifically 1 mg) of a measurement sample, and stirring is performed at room temperature using a magnetic stirrer or the like. Go and dissolve well. Subsequently, after processing with a membrane filter having a pore size of 0.45 to 0.50 μm, the solution is injected into GPC.

  As GPC measurement conditions, the column is stabilized at 40 ° C., THF is allowed to flow at a flow rate of 1 ml per minute, and about 100 μl of a sample having a concentration of 1 mg / ml is injected for measurement. The column is preferably used in combination with a commercially available polystyrene gel column. For example, combinations of Shodex GPC KF-801, 802, 803, 804, 805, 806, and 807 manufactured by Showa Denko KK and TSKgel G1000H, G2000H, G3000H, G4000H, G6000H, G7000H, TSK guard column manufactured by Tosoh Corporation Combinations can be mentioned. As a detector, a refractive index detector (IR detector) or a UV detector may be used. In the measurement of the molecular weight of a sample, the molecular weight distribution of the sample is calculated using a calibration curve prepared using monodisperse polystyrene standard particles. About 10 points may be used as polystyrene for preparing a calibration curve.

Next, the constitution of the organophotoreceptor of the present invention will be described. A surface layer is formed using the AB type or BAB type block copolymer as described above, and a B component is formed on the surface layer. In order to form a domain having a number average primary particle size of 1 to 100 nm in which the B is aggregated, the proportion of the B component in the AB type or BAB type block polymer is 5.1% by mass or more and 45% by mass. % Block copolymer is preferably used. If it is less than 5.1% by mass, it is difficult to form a domain structure in which B components are aggregated, and if it exceeds 45% by mass, it is difficult to form a continuous matrix structure (sea structure) and wear resistance of the surface layer. Characteristics are likely to deteriorate.

  Further, it is preferable that the B component polysiloxane component has a relatively low degree of polymerization having a repeating structure of about 10 to 1,000. If the polymer structure of the B component is too large, the B component is less likely to aggregate and a domain structure is difficult to form.

  In addition, selection of a solvent that dissolves the AB block polymer is also important for forming the surface layer. That is, it is preferable to select a good solvent (a solvent that dissolves the matrix component well) in the polycarbonate as the matrix component of the block polymer and use it as a coating solvent for the surface layer. For example, it is preferable to use a solvent such as tetrahydrofuran or toluene.

  By forming the surface layer under such conditions, it is possible to form a surface layer having a domain structure in which B component polysiloxanes are aggregated in a matrix structure (sea) composed of the A component polycarbonate component.

  The number average primary particle size of the domains according to the present invention was observed by observing 100 particles randomly as primary particles by magnifying a cross section cut by a microtome in a direction perpendicular to the surface layer by a transmission electron microscope to 10,000 times ( If necessary, a photograph is taken), and the number average diameter of the ferret diameter is measured by image analysis.

  The domain density of the surface layer is also determined by observing the same cross-sectional structure.

The domain density of the surface layer according to the present invention is preferably such that ² to 10000 domains are distributed with respect to a cross-sectional area of 10000 nm 2. The presence of domains at such a density allows the surface of the photoreceptor to be kept at a low surface energy state, prevents toner filming on the surface, and improves the transferability of the toner image from the photoreceptor to the transfer medium. Image defects such as voids can be prevented.

  Moreover, it describes below about layer structures other than the said surface layer.

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

The structure of the photoreceptor according to the present invention contains the AB block copolymer or BAB block copolymer (block copolymer of the A component and the B component) having the polycarbonate component and the polysiloxane component. However, it is not particularly limited as long as it has a surface layer of a sea-island structure in which a domain in which the polysiloxane components are aggregated, and examples thereof include the following configurations;
1) A structure in which a charge generation layer and a charge transport layer are sequentially laminated as a photosensitive layer on a conductive support. 2) A charge generation layer, a first charge transport layer and a second charge transport layer are formed as a photosensitive layer on a conductive support. Sequentially stacked configuration;
3) A structure in which a single layer containing a charge transport material and a charge generation material is formed as a photosensitive layer on a conductive support;
4) A structure in which a charge transport layer and a charge generation layer are sequentially laminated as a photosensitive layer on a conductive support;
5) A structure in which a surface protective layer is further formed on the photosensitive layer of the photoreceptors 1) to 5) above.

  The photoconductor may have any of the above configurations. The surface layer of the photoreceptor is a layer in contact with the air interface. When only a single-layer photosensitive layer is formed on the conductive support, the photosensitive layer is the surface layer, and the conductive layer In the case where a single-layered or laminated photosensitive layer and a surface protective layer are laminated on the conductive support, the surface protective layer is the outermost surface layer. In the present invention, the configuration 2) is most preferably used. Note that, even if the photoreceptor according to the present invention has any configuration, an undercoat layer may be formed on the conductive support prior to the formation of the photosensitive layer.

  The charge transport layer according to the present invention means a layer having a function of transporting charge carriers generated in the charge generation layer by light exposure to the surface of the organic photoreceptor, and the specific detection of the charge transport function is performed by This can be confirmed by laminating the generation layer and the charge transport layer on the conductive support and detecting the optical conductivity.

  A specific configuration of the photoreceptor will be described below by taking as an example the layer configuration of 2) which is most preferably used in the present invention.

Conductive Support As the conductive support used in the photoreceptor according to the present invention, a sheet-like or cylindrical conductive support is used.

  The cylindrical conductive support according to the present invention means a cylindrical support necessary to be able to form an endless image by rotating, and the cylindricity is preferably 5 to 40 μm, more preferably 7 to 30 μm. .

  This cylindricity is based on JIS standard (B0621-1984). That is, when the cylindrical substrate is sandwiched between two coaxial geometric cylinders, it is represented by the difference in radius at the position where the distance between the two coaxial cylinders is minimum. In the present invention, the difference in radius is represented by μm. The method of measuring the cylindricity is obtained by measuring the roundness of 7 points in total, that is, 2 points 10 mm on both ends of the cylindrical substrate, 4 points of the central part, and 4 points obtained by dividing the distance between the both ends. The measuring device can be measured using a non-contact universal roll diameter measuring machine (manufactured by Mitutoyo Corporation).

As a material for the conductive support, 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 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, an intermediate layer having a barrier function may be provided 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.

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

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

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

Specific examples of the N-type semiconducting fine particles include fine particles of titanium oxide (TiO ₂ ), zinc oxide (ZnO), tin oxide (SnO ₂ ), etc. In the present invention, titanium oxide is particularly preferably used. It is done.

  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 depositing alumina, silica, or zirconia on the surface of the N-type semiconducting 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, CGMs such as titanyl phthalocyanine having a maximum peak at a Bragg angle 2θ of 27.2 ° with respect to Cu—Kα rays and benzimidazole perylene having a maximum peak at 2θ of 12.4 have 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 As described above, in the present invention, the charge transport layer is preferably composed of a plurality of charge transport layers, and the surface layer structure of the present invention is applied to the uppermost charge transport layer.

  The charge transport layer contains a charge transport material (CTM) and a binder resin that disperses and forms a CTM. Other substances may contain additives such as antioxidants as necessary.

  As the charge transport material (CTM), a known hole transport property (P-type) charge transport material (CTM) is preferably used. For example, a triphenylamine derivative, a hydrazone compound, a styryl compound, a benzidine compound, a butadiene compound, or the like can be used. These charge transport materials are usually dissolved in a suitable binder resin to form a layer. In particular, a charge transport material that does not absorb the wavelength of laser light for image exposure is preferably used.

  The binder resin used for the charge transport layer (CTL) may be either a thermoplastic resin or a thermosetting resin. For example, polystyrene, acrylic resin, methacrylic resin, vinyl chloride resin, vinyl acetate resin, polyvinyl butyral resin, epoxy resin, polyurethane resin, phenol resin, polyester resin, alkyd resin, polycarbonate resin, silicone resin, melamine resin, and these resins A copolymer resin containing two or more of the repeating unit structures. In addition to these insulating resins, high molecular organic semiconductors such as poly-N-vinylcarbazole can be used. Of these, polycarbonate resins are most preferred because of their low water absorption and good CTM dispersibility and electrophotographic characteristics.

  The ratio of the binder resin to the charge transport material 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 20 μm or less, and more preferably 10 to 16 μm. When the film thickness exceeds 20 μm, laser absorption and scattering in the charge transport layer increase, and sharpness and residual potential tend to increase.

  The surface layer according to the present invention preferably contains an antioxidant. The presence of an antioxidant in the surface layer of the sea-island structure in which the low surface energy components in the block copolymer are aggregated to form a domain prevents the surface layer from deteriorating, thereby degrading the transfer characteristics and cleaning properties. Can be prevented. Typical examples of the antioxidants are those that prevent the action of oxygen under conditions of light, heat, discharge, etc. on auto-oxidizing substances present in the organic photoreceptor or on the surface of the organic photoreceptor, It is a substance that has the property of inhibiting. Typical examples include the following compound groups.

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

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

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

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

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

  In the image forming unit C, as an image forming unit, a drum-shaped photoconductor 21 as an image carrier, a charging means (charging step) 22 for charging the photoconductor 21 on the outer periphery thereof, and a surface potential of the charged photoconductor. Potential detecting means 220 for detecting the toner, developing means (developing process) 23, transfer / conveying belt device 45 serving 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 photoreceptor 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 an example of this 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 polymerized 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. 2 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 arranged 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 photoconductor 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 photoconductor 1C as a first image carrier, a charging unit 2C, an exposure unit 3C, a developing unit 4C, 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 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. 3 shows a color image forming apparatus using the organic photoreceptor of the present invention (a copying machine having at least a charging means, an exposure means, a plurality of developing means, a transfer means, a cleaning means, and an intermediate transfer body around the organic photoreceptor. 1 is a cross-sectional view of a configuration of a laser beam printer. 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 not activated and do not act on the photoreceptor 1. The yellow toner image of the first color is not affected by the second to fourth developing devices.

  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 first color yellow toner image formed and supported on the photosensitive member 1 is applied to the intermediate transfer member 70 from the primary transfer roller 5a in the process of passing through the nip portion between the photosensitive member 1 and the intermediate transfer member 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 method of the present invention is generally applicable to electrophotographic apparatuses such as electrophotographic copying machines, laser printers, LED printers, and liquid crystal shutter printers. Further, displays, recording, light printing, plate making and facsimiles using electrophotographic technology are applied. The present invention can be widely applied to such devices.

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

Production of Photoreceptor 1 Photoreceptor 1 was produced as follows.

The surface of the cylindrical aluminum support was cut to prepare a conductive support having a ten-point surface roughness Rz = 1.5 (μm).
<Intermediate layer>
The following intermediate layer dispersion was diluted twice with the same mixed solvent, and allowed to stand overnight, followed by filtration (filter; rigesh mesh 5 μm filter manufactured by Nihon Pall) to prepare an intermediate layer coating solution.

Polyamide resin CM8000 (manufactured by Toray Industries, Inc.) 1 part Inorganic particles: Titanium oxide (Number average primary particle size 35 nm: Titanium oxide treated with silica / alumina and methylhydrogenpolysiloxane) 3 parts Methanol 10 parts are mixed as a disperser Using a sand mill, batch dispersion was performed for 10 hours to prepare an intermediate layer dispersion.

  It apply | coated so that it might become a dry film thickness of 1.0 micrometer on the said support body using the said coating liquid.

<Charge generation layer: CGL>
Titanyl phthalocyanine pigment (a titanyl phthalocyanine pigment having a maximum diffraction peak at 27.3 ° in the Bragg angle (2θ ± 0.2 °) of the characteristic X-ray diffraction spectrum of Cu-Kα) 24 parts Polyvinyl butyral resin “ESREC BL- 1 ”(manufactured by Sekisui Chemical Co., Ltd.) 12 parts 2-butanone / cyclohexanone = 4/1 (v / v) 300 parts The above composition was mixed and dispersed using a sand mill to prepare a charge generation layer coating solution. This coating solution was applied by a dip coating method to form a charge generation layer having a dry film thickness of 0.5 μm on the intermediate layer.

<Charge transport layer 1 (CTL1)>
Charge transport material (4,4′-dimethyl-4 ″-(α-phenylstyryl) triphenylamine) 225 parts Polycarbonate (Z300: manufactured by Mitsubishi Gas Chemical Company) 300 parts Antioxidant (Exemplary Compound AO2-1) 6 parts Dichloromethane 2000 parts Silicon oil (KF-54: manufactured by Shin-Etsu Chemical Co., Ltd.) 1 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. Then, drying was performed 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)>
Charge transport material (4,4′-dimethyl-4 ″-(α-phenylstyryl) triphenylamine) 150 parts Binder: (Block copolymer of Block 1) 300 parts Antioxidant (Exemplary Compound AO2-1) 12 parts THF: Tetrahydrofuran 1200 parts Silicon oil (KF-54: manufactured by Shin-Etsu Chemical Co., Ltd.) 4 parts were mixed and dissolved to prepare a charge transport layer coating solution 2. This coating solution was placed on the charge transport layer 1 Coating was performed with a circular slide hopper type coating machine, drying was performed at 110 ° C. for 70 minutes, and a charge transport layer 2 having a dry film thickness of 2.0 μm was formed.

Production of photoconductors 2 to 7 Photoconductors 2 to 7 were produced in the same manner as photoconductor 1 except that the binder type of charge transport layer 2 (CTL2) was changed as shown in Table 2 in production of photoconductor 1. did.

Production of Photoreceptor 8 Photoreceptor 8 was produced in the same manner except that the following graft copolymer (GP1) was used instead of block 1 of charge transport layer 2 of photoreceptor 1.

  The measurement results of the domain diameters and domain densities of these photoreceptors 1 to 8 were as shown in Table 2.

<< 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.) basically having the configuration shown in FIG. 2, and color images were evaluated.

Evaluation condition Photoconductor linear velocity: 220 mm / sec
《Image evaluation》
Original image with A4 paper, 10,000 text images, solid white image, black solid image, halftone image in high temperature and high humidity (30 ° C, 80% RH) environment with each photoconductor attached to the above full color multifunction device 8050 A copy 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.

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 (evaluated with cyan toner image)
The toner image on the intermediate transfer member was transferred to a transparent adhesive sheet, and the transferred 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)
(Cleanability)
After the above evaluation, without changing the cleaning blade, only the linear load of the cleaning blade contacting the photoconductor was changed from 18 (N / m) to 9 (N / m), and 10,000 continuous copies were made. The cleaning performance was evaluated.

◎ Throughout the printing of 10,000 sheets, there is no occurrence of cleaning defects such as toner slipping out (good)
○: Spiral cleaning defects such as toner slipping occurred during printing on 10,000 sheets, but no toner filming was found on the photoconductor, and there was no practical problem (no problem in practical use)
×: Continuous printing failure (2 or more) occurs during printing on 10,000 sheets, or toner filming is observed on the photoreceptor (practical problem)
Measurement of Contact Angle The contact angles of these photoconductors 1 to 8 were measured before and after the 10,000 copies were evaluated (start (St) and end (End)), and the results are shown in Table 3. The contact angle was measured by the method described above.

  The evaluation results are shown in Table 3 below.

  As is apparent from Table 3, the organic photoreceptor of the present invention having a surface layer having a sea-island structure forming a domain in which the low surface energy components in the binder resin are aggregated has a toner image reproducibility on the photoreceptor, intermediate While good results were obtained in all evaluations of toner image reproducibility and cleaning performance on the transfer body, a photoreceptor that does not have a domain in which low surface energy components are aggregated in the surface layer has a void. This often occurs, the reproducibility of the dot image on the intermediate transfer member is deteriorated, and the cleaning property is also deteriorated.

<< Evaluation 2 >>
As shown in Table 4, the photosensitive member No. 3 and no. 8 was mounted on a remodeling machine of a commercially available color printer magiccolor 2300 (manufactured by Konica Minolta Business Technologies Co., Ltd.) basically having the configuration shown in FIG.

  The results are shown in Table 4.

  As is apparent from Table 4, the organic photoreceptor No. 1 of the present invention. The color image produced using No. 3 has good results in all of the reproducibility of the toner image on the photosensitive member, the reproducibility of the toner image on the intermediate transfer member, and the cleaning property. On the other hand, organic photoreceptor No. The color image produced using No. 8 has deteriorated reproducibility and cleaning properties of the toner image on the intermediate transfer member.

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

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

Claims (10)

In an organic photoreceptor having a photosensitive layer on a conductive support, an AB block copolymer or a B-A-B block copolymer (A) in which the surface layer of the organic photoreceptor has the following polycarbonate component and polysiloxane component: And an organic photoreceptor having a sea-island structure in which a domain in which the polysiloxane components are aggregated is formed.
A component: Polycarbonate component B component: Polysiloxane component 2. The organic photoreceptor according to claim 1, wherein the polycarbonate component has a structure represented by the following general formula (1), and the polysiloxane component has a structure represented by the following general formula (2).

(In General Formula (1), Y ^{1 to} Y ⁸ are each independently a hydrogen atom, a saturated aliphatic hydrocarbon group having 1 to 10 carbon atoms, an unsaturated aliphatic hydrocarbon group having 3 to 10 carbon atoms, and a halogen atom. , A halogenated alkyl group, an alkoxyl group, an optionally substituted aromatic hydrocarbon group having 6 to 20 carbon atoms, X is the following divalent linking group;

And an aromatic ring, a single bond, a lactone, and fluorene, wherein R ^{1 to} R ⁷ are each independently a hydrogen atom, a saturated aliphatic hydrocarbon group having 1 to 10 carbon atoms that may have a substituent, and a substituent. An unsaturated aliphatic hydrocarbon group having 3 to 10 carbon atoms, a halogen, an alkoxyl group, and an aromatic hydrocarbon group having 6 to 20 carbon atoms that may have a substituent. , Z represents a substituted or unsubstituted aliphatic hydrocarbon group having 3 to 20 carbon atoms, a is an integer of 0 to 4; l is an integer of 1 to 6; m is an integer of 2 to 20 Show. )
(In the general formula (2), R ¹³ represents a divalent organic residue containing aliphatic and / or aromatic, and W represents a single bond, O, CO, COO, NH, NHCO, S, SO, SO _2. R ^{8 to} R ¹² are each independently a saturated aliphatic hydrocarbon group having 1 to 10 carbon atoms which may have a substituent or a carbon number having 6 to 20 which may have a substituent. The following aromatic hydrocarbon groups are shown, and n is an integer of 1 to 500.) The organophotoreceptor according to claim 1, wherein the domain is a domain having a number average primary particle size of 1 to 100 nm. The organophotoreceptor according to claim 1 or 2, wherein the surface layer has a domain density of 1 to 10,000 per 1 x 10 ⁴ nm ² . The polycarbonate component of the A component has at least one repeating structure selected from the following polycarbonate (Z), polycarbonate (DM), and polycarbonate (A). The organophotoreceptor described.

The organophotoreceptor according to claim 1, wherein the number average molecular weight of the component A is 0.5 to 300,000. The organic photoreceptor according to claim 1, wherein the organic photoreceptor has an intermediate layer, a charge generation layer, and a charge transport layer on a conductive support. An organic photoreceptor, charging means for charging the organic photoreceptor, latent image forming means for forming an electrostatic latent image on the charged organic photoreceptor, developing means for developing the electrostatic latent image into a toner image, Transfer means for transferring the visualized toner image onto the transfer medium from the organic photoreceptor, charge eliminating means for removing the charge remaining on the organic photoreceptor after the transfer of the toner image, and residual on the organic photoreceptor after the transfer In a process cartridge used in an image forming apparatus having a cleaning means for removing toner to be removed, the surface layer of the organic photoreceptor has an AB block copolymer or a B-A-B block copolymer having the following polycarbonate component and polysiloxane component. An organic photoreceptor having a sea-island structure containing a polymer (a block copolymer of component A and component B) and forming a domain in which the polysiloxane components are aggregated, charging means, and latent image Forming means, a developing means, a transfer medium, at least one means discharging means and the cleaning means are integrally supported, the process cartridge, which is a detachably mounted to the image forming apparatus main body.
A component: Polycarbonate component B component: Polysiloxane component An organic photoreceptor, charging means for charging the organic photoreceptor, latent image forming means for forming an electrostatic latent image on the charged organic photoreceptor, developing means for developing the electrostatic latent image into a toner image, A transfer medium for transferring the visualized toner image from the organic photoreceptor onto the transfer medium, a charge eliminating means for removing the charge on the organic photoreceptor after the transfer, and a residual toner on the organic photoreceptor after the transfer are removed. In the image forming method having a cleaning means, the surface layer of the organophotoreceptor has an AB block copolymer or a B-A-B block copolymer (A component and B component) having the following polycarbonate component and polysiloxane component: An image forming method using an organic photoreceptor having a sea-island structure containing a block copolymer) and forming a domain in which the polysiloxane components are aggregated.
A component: Polycarbonate component B component: Polysiloxane component An organic photoreceptor, charging means for charging the organic photoreceptor, latent image forming means for forming an electrostatic latent image on the charged organic photoreceptor, developing means for developing the electrostatic latent image into a toner image, A transfer medium for transferring the visualized toner image from the organic photoreceptor onto the transfer medium, a charge eliminating means for removing the charge on the organic photoreceptor after the transfer, and a residual toner on the organic photoreceptor after the transfer are removed. In the image forming apparatus having a cleaning means, the surface layer of the organophotoreceptor has an AB block copolymer or a B-A-B block copolymer (A component and B component) having the following polycarbonate component and polysiloxane component: An image forming apparatus using an organic photoreceptor having a sea-island structure containing a block copolymer) and forming a domain in which the polysiloxane components are aggregated.
A component: Polycarbonate component B component: Polysiloxane component

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