JP2007011026A - Conductive member, process cartridge, and image forming apparatus - Google Patents

Abstract

Provided is a conductive member capable of maintaining a stable gap with a latent image carrier with high accuracy.
A conductive support, an electric resistance adjusting layer formed on the conductive support, and the image so that the electric resistance adjusting layer and the image carrier hold a certain gap. In the conductive member 10 having gap holding members 5 and 5 formed at both ends of the electric resistance adjusting layer 3 in contact with the carrier, the gap holding members 5 and 5 in contact with the image carrier It is assumed that a chamfered shape 53 is formed at the end of the outer peripheral surface 51.
[Selection] Figure 1

Description

  The present invention relates to a conductive member used in an image forming apparatus such as a copying machine, a laser beam printer, and a facsimile, a process cartridge having the conductive member, and an image forming apparatus having the process cartridge.

  In a conventional electrophotographic image forming apparatus such as an electrophotographic copying machine, a laser printer, and a facsimile, a charging member that charges an image carrier (photosensitive drum) and toner on the image carrier are used. A conductive member is used as a transfer member that performs a transfer process. FIG. 8 is an explanatory diagram of an electrophotographic image forming apparatus having a conventional charging roller.

  In FIG. 8, reference numeral 120 denotes a conventional electrophotographic image forming apparatus. A conventional electrophotographic image forming apparatus 120 includes an image carrier 101 on which an electrostatic latent image is formed, a charging roller 102 that performs charging processing in contact with the image carrier 101, an exposure unit 103 such as a laser beam, and an image. A developing roller 104 for attaching toner to the electrostatic latent image on the carrier 101, a power pack 105 for applying a DC voltage to the charging roller 102, and a transfer roller for transferring the toner image on the image carrier 101 to the recording paper 107 106, a cleaning device 108 for cleaning the image carrier 101 after the transfer process, and a surface potential meter 109 for measuring the surface potential of the image carrier 101.

  The conventional electrophotographic image forming apparatus 120 is a process cartridge detachable apparatus. That is, in the conventional electrophotographic image forming apparatus 120, the process equipment including the image carrier 101, the charging roller 102, the developing roller 104, and the cleaning device 108 can be detachably attached to the main body of the image forming apparatus. The process cartridge 110 is used. The process cartridge 110 only needs to include at least the image carrier 101 and the charging roller 102. The process cartridge 110 is connected to a drive system and an electrical system on the image forming apparatus main body side by being mounted at a predetermined position on the image forming apparatus. In FIG. 5, functional units normally required in other electrophotographic processes are omitted because they are not required in this specification.

  Next, a basic image forming operation of the conventional electrophotographic image forming apparatus 120 will be described.

  When a DC voltage is supplied from the power pack 105 to the charging roller 102 in contact with the image carrier 101, the surface of the image carrier 101 is uniformly charged to a high potential. Immediately after that, when image light is irradiated onto the surface of the image carrier 101 by the exposure means 103, the potential of the irradiated portion of the image carrier 101 decreases. It is known that such a charging mechanism to the surface of the image carrier 101 by the charging roller 102 is discharge according to Paschen's law in a minute space between the charging roller 102 and the image carrier 101.

  Since the image light has a light amount distribution according to white / black of the image, when the image light is irradiated, the potential distribution corresponding to the recorded image on the surface of the photosensitive drum 101 by the irradiation of the image light, that is, An electrostatic latent image is formed. When the portion of the photosensitive drum 101 on which the electrostatic latent image is formed in this way passes through the developing roller 104, toner adheres according to the level of the potential, and a toner image that visualizes the electrostatic image is formed. Is done. The recording paper 107 is conveyed by a registration roller (not shown) at a predetermined timing to the portion of the photosensitive drum 101 where the toner image is formed, and overlaps the toner image. Then, after the toner image is transferred onto the recording paper by the transfer roller 106, the recording paper 107 is separated from the photosensitive drum 101. The separated recording paper 107 is conveyed through a conveyance path, heated and fixed by a fixing unit (not shown), and then discharged outside the apparatus. When the transfer is completed in this manner, the surface of the photosensitive drum 101 is cleaned by the cleaning device 108, and the residual charge is removed by a quenching lamp (not shown), so that the next image forming process is performed. Prepared for.

  FIG. 9 is a cross-sectional view showing an example of a conventional conductive member. As shown in FIG. 9, the conductive indicator 201, the electric resistance adjusting layer 202 formed on the conductive indicator 201, and the ring-shaped gap holding member 203 formed at both ends of the electric resistance adjusting layer 202. , 203, the gap holding members 203, 203 are thermoplastic resins that satisfy the durometer hardness: HDD30 to HDD70 and the wear mass of the Taber type abrasion tester: 10 mg / 1000 cycles or less. The electroconductive member (charging roller) 210 comprised by this was proposed (refer patent document 1).

In the conductive member 210, the gap holding member 203 is press-fitted into both end portions of the electric resistance adjusting layer 202. In this conductive member 210, a gap holding member 203 is formed at the end of the electric resistance adjusting layer 202, and the gap holding member 203 is in contact with the end surface of the electric resistance adjusting layer 202 and the conductive support 201. Further, in this conductive member 210, in order to improve long-term reliability, an adhesive is applied between the gap holding member 203 and the conductive support 201 to ensure that the gap holding member 203 is fixed. However, since the linear expansion coefficients of the gap holding member 203 made of resin and the conductive support 201 made of metal are greatly different from each other, the conductive material becomes conductive in a low temperature environment or a high temperature environment. There is a possibility that peeling occurs at the interface between the conductive support 201 and the gap holding member 203, and therefore, the reliability over a long period of time is slightly inferior. In addition, the adhesive strength at the interface between the conductive support 201 and the gap holding member 203 is weakened by energization for a long time. If the gap holding member 203 moves, the gap (gap) accuracy fluctuates, so that uneven charging tends to occur. In particular, in order to make the gap highly accurate, if the electric resistance adjusting layer 202 and the gap holding member 203 are not sufficiently fixed, the gap holding member 203 rotates during removal processing such as grinding and cutting. It was necessary to fix the gap holding member 203 more firmly by applying an agent.
Japanese Patent Laid-Open No. 2005-24830

  As described above, since it is required to form a highly accurate gap between the electric resistance adjusting layer 202 and the image carrier, a step (gap) is formed between the electric resistance adjusting layer 202 and the gap holding member 203. After the members are arranged, the outer diameters of both members are formed by removal processing such as cutting and grinding. However, when the tool cuts into the workpiece by removing the outer diameter portion, the workpiece may be deformed (elastically deformed) due to machining resistance, and the deformed portion may return and rise after the tool has passed. Further, similarly, chips may be generated discontinuously in the cut portion, and burrs tend to be easily generated.

  As described above, since the burrs and the bulge of the outer diameter were likely to occur at the incision start part and the stepped part of the outer diameter during the removal processing, the conductive member on which the bulge and burrs were generated is supported by the latent image. When combined with the body, an error occurs in the gap, and there is a problem that a highly accurate gap cannot be secured. Therefore, it has been necessary to remove the factor that causes noise of the outer diameter of the gap holding member 203 and to realize high-precision shape accuracy.

  Therefore, in view of the above-described problems, an object of the present invention is to provide a conductive member, a process cartridge, and an image forming apparatus that can maintain a stable gap with a latent image carrier with high accuracy. .

  In order to solve the above-mentioned problems, the present invention has been made in accordance with the present invention. The present invention provides a conductive support, an electric resistance adjusting layer formed on the conductive support, the electric resistance adjusting layer, and an image carrier. A gap holding member formed on both ends of the electric resistance adjusting layer in contact with the image carrier so as to hold a constant gap, in the conductive member, the gap contacting the image carrier A chamfered shape is formed at the end of the outer peripheral surface of the holding member.

  The invention described in claim 2 is characterized in that, in the invention described in claim 1, the chamfered shape of the gap holding member is an R shape or a shape having a curve.

  The invention described in claim 3 is the invention described in claim 1 or 2, characterized in that the chamfered shape of the gap holding member is formed such that curved surfaces having different curvature radii are continuous.

  According to a fourth aspect of the present invention, in the invention according to any one of the first to third aspects, when the outer peripheral surface of the gap holding member abuts on the image carrier, the outer peripheral surface of the image carrier and the The height difference of the outer peripheral surface of the gap holding member with respect to the outer peripheral surface of the electrical resistance adjusting layer is provided so that a gap having a constant interval is formed between the outer peripheral surface of the conductive member and the conductive member. .

  The invention described in claim 5 is the invention described in claim 4, wherein a difference in height of the outer peripheral surface of the gap holding member with respect to the outer peripheral surface of the electric resistance adjusting layer is set on the conductive support. It is formed by integral processing by removal processing such as cutting and grinding applied to the outer peripheral surface of the gap holding member and the outer peripheral surface of the electric resistance adjusting layer installed on the conductive support. And

  The invention described in claim 6 is the invention described in any one of claims 1 to 5, wherein the chamfered shape of the gap holding member is applied from the side surface of the gap holding member toward the outer peripheral surface. It is formed by removal processing such as cutting and grinding.

  The invention described in claim 7 is the invention described in any one of claims 1 to 6, wherein the conductive member has a cylindrical shape.

  The invention described in claim 8 is characterized in that, in the invention described in any one of claims 1 to 7, the conductive member is a charging member.

  The invention according to claim 9 is characterized in that the charging member according to claim 8 is provided so as to be disposed close to the member to be charged.

  The invention described in claim 10 has the process cartridge described in claim 9.

  As described above, according to the first aspect of the present invention, the chamfered shape is formed at the end portion of the outer peripheral surface of the gap holding member, that is, the boundary with the end surface portion, so that it contacts the image carrier. Since the generation of noise factors can be prevented at the end of the outer peripheral surface of the gap holding member, a highly accurate gap can be formed at the time of contact with the image carrier. A conductive member capable of realizing shape accuracy can be provided.

  According to the second aspect of the present invention, since the chamfered shape is an R shape or a curved shape, it is possible to form an accurate gap when contacting the image carrier, and damage to the image carrier. Can be reduced.

  According to the third aspect of the present invention, since the curves having different radii of curvature with different chamfered shapes continuously form a curved surface, it is possible to form an accurate gap when contacting the image carrier. The damage to the image carrier can be reduced.

  According to the fourth aspect of the present invention, when the outer peripheral surface of the gap holding member comes into contact with the image carrier, there is a gap between the outer peripheral surface of the image carrier and the outer peripheral surface of the conductive member. Since the height difference of the outer peripheral surface of the gap holding member with respect to the outer peripheral surface of the electric resistance adjusting layer is provided, the gap between the image carrier and the image carrier can be kept constant with high accuracy. In addition, even if the electrical resistance adjustment layer in which the gap holding member is disposed changes due to environmental fluctuations, it can follow the change in the electrical resistance adjustment layer, and therefore fluctuations in the gap can be suppressed.

  According to the fifth aspect of the present invention, the difference in height of the outer peripheral surface of the gap holding member with respect to the outer peripheral surface of the electric resistance adjusting layer is such that the outer peripheral surface of the gap holding member installed on the conductive support and the conductive support. Since it is formed by integral processing by removal processing such as cutting and grinding applied to the outer peripheral surface of the electrical resistance adjustment layer installed on the body, the gap holding member and the electrical resistance adjustment layer The difference in height can be formed by integral processing. For this reason, the fluctuation (shake) of the gap formed between the outer peripheral surface of the image carrier and the outer peripheral surface of the electric resistance adjusting layer is reduced, and the accuracy of the gap is reduced. Can be further enhanced.

  According to the invention described in claim 6, since the chamfered shape is formed by removal processing applied from the side surface to the outer peripheral surface of the gap holding member, noise factors such as bulging of the deformed portion due to processing resistance, burrs, etc. Therefore, it is possible to more reliably prevent the occurrence of the above-described problem, so that it is possible to form an accurate gap when contacting the image carrier.

  According to the seventh aspect of the present invention, since the conductive member has a cylindrical shape, the conductive member can be rotationally driven. For this reason, the surface caused by energization stress is prevented by preventing continuous discharge from the same location. The chemical deterioration of the resin can be reduced, so that the longevity can be extended.

  According to the eighth aspect of the present invention, since the conductive member is the charging member, the surface of the image carrier can be charged in a non-contact manner. Is made of a hard material, so that the accuracy can be increased, and thus uneven charging can be prevented.

  According to the ninth aspect of the present invention, since the charging member is a process cartridge provided so as to be disposed close to the member to be charged, a stable image quality can be obtained over a long period of time, and replacement is also possible. User maintenance is possible and simplified.

  According to the tenth aspect of the present invention, since the image forming apparatus having the process cartridge is used, an image with high reliability and high image quality can be obtained.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a cross-sectional view of a conductive member showing an embodiment of the present invention. FIG. 2 is an explanatory view showing a method of forming the first chamfered shape of the gap holding member according to the embodiment of the present invention. FIG. 3 is a schematic diagram showing a state in which the conductive member is arranged on the image carrier. FIG. 4 is an explanatory diagram of an image forming apparatus showing an embodiment of the present invention. FIG. 5 is an explanatory view showing a method of forming the second chamfered shape of the gap holding member according to the embodiment of the present invention. FIG. 6 is an explanatory view showing a method of forming the third chamfered shape of the gap holding member according to the embodiment of the present invention. FIG. 7 is an enlarged view of the gap holding member when chamfering is not performed.

  In FIG. 1, reference numeral 10 denotes a conductive member (charging roller). The conductive member (charging roller) 10 includes a conductive support 1, an electric resistance adjustment layer 3 formed on the conductive support 1, the electric resistance adjustment layer 3, and an image carrier (6 in FIG. 3). Are held on both ends of the electric resistance adjusting layer 3 in contact with the image carrier so as to hold a constant gap (see G in FIG. 3). ,have. The electrical resistance adjusting layer 3 is fixed to the conductive support 1 with an adhesive 2. In FIG. 1, 4 is a surface layer.

  A chamfered shape 53 is formed at the end of the outer peripheral surface 51 of the gap holding member 5, 5 that contacts the image carrier. The chamfering angle of the chamfered shape 53 is preferably 20 ° or more and 60 ° or less. If the chamfering angle is small, the chips are likely to be wound at the time of cutting, and if the chamfering angle is large, the effect of preventing the above-described edge bulge and burr generation is reduced.

  Thus, since the chamfered shape 53 is formed at the end of the outer peripheral surface 51 of the gap holding members 5, 5, that is, at the boundary with the end face portion 52, the gap holding members 5, 5 coming into contact with the image carrier. The generation of noise factors can be prevented from occurring at the end of the outer peripheral surface 51, etc., so that a highly accurate gap G can be formed at the time of contact with the image carrier. Thus, it is possible to provide the conductive member 10 capable of realizing a good shape accuracy.

  As shown in FIG. 3, the conductive member 10 of the present invention is disposed in contact with the image carrier 6 with an arbitrary pressure. The gap holding members 5 and 5 are formed in a non-image forming area excluding the image forming area. In this state, the image carrier 6 can be charged by applying a voltage to the charging member. When the conductive member 10 is used as a transfer member, it can be performed in the same manner. The gap G between the conductive member 10 and the image carrier 6 needs to be kept at a predetermined value, and is preferably 100 μm or less. When the gap G becomes large, it is necessary to increase the voltage application condition to the conductive member 10, and therefore electrical deterioration and abnormal discharge of the image carrier 6 are likely to occur.

  Further, the gap holding members 5 and 5 are required to stably form the gap G with the image carrier 6 over the environment and for a long period (time). For this purpose, the hygroscopicity and the wear resistance are small. Since materials are desirable, general-purpose resins such as polyethylene (PE), polypropylene (PP), polymethyl methacrylate (PMMA), polystyrene (PS), and copolymers thereof (AS, ABS), PC, urethane, And fluorine.

In particular, in order to securely fix the gap holding members 5 and 5 to the conductive support 1, the adhesive 2 is applied and bonded and fixed as in the present invention. The gap holding members 5 and 5 are preferably made of an insulating material and preferably have a volume resistivity of 10 ¹³ Ωcm or higher. The reason why insulation is necessary is to eliminate the occurrence of leakage current with the base of the image carrier 6. And the space | gap holding members 5 and 5 are shape | molded by a shaping | molding process.

  The adhesive surfaces of the gap holding members 5 and 5 are preferably surface-treated with an active gas in advance. As described above, when the bonding surfaces of the gap holding members 5 and 5 are previously surface-treated with the active gas, the conductive support 1 and the gap holding members 5 and 5 are bonded more firmly. Can do.

The electric resistance adjusting layer 3 is formed of a thermoplastic resin composition in which a polymer type ion conductive material is dispersed. The volume resistivity of the electric resistance adjusting layer 3 is preferably 10 ⁶ to 10 ⁹ Ωcm. If it exceeds 10 ⁹ Ωcm, charging ability and transfer ability are insufficient, and if the volume resistivity is as low as 10 ⁶ Ωcm, leakage due to voltage concentration on the entire image carrier 6 occurs.

  The thermoplastic resin composition used for the electrical resistance adjusting layer 3 is not particularly limited, but polyethylene (PE), polypropylene (PP), polymethyl methacrylate (PMMA), polystyrene (PS) and copolymers thereof. A general-purpose resin such as (AS, ABS) is preferable because it can be easily molded.

  The polymer type ion conductive material dispersed in the thermoplastic resin composition is preferably a polymer compound containing a polyether ester amide component. Polyether ester amide is an ion conductive polymer material, and is uniformly dispersed and immobilized at a molecular level in a matrix polymer. Accordingly, there is no variation in resistance value due to poor dispersion as seen in a composition in which an electron conductive conductive agent such as metal oxide or carbon black is dispersed. Moreover, since it is a polymer material, bleed-out hardly occurs. About a compounding quantity, since it is necessary to make resistance value into a desired value, it is necessary to make a thermoplastic resin into 30 to 70 weight% and a polymeric ion conductive agent to 70 to 30 weight%.

  There is no restriction | limiting in particular regarding the manufacturing method of a thermoplastic resin composition, It can manufacture easily by melt-kneading the mixture of each material with a biaxial kneader, a kneader, etc. The electric resistance adjusting layer 3 can be easily formed on the conductive support 1 by coating the conductive support 1 with the semiconductive resin composition by means of extrusion molding or injection molding. Can do.

  If only the electric resistance adjusting layer 3 is formed on the conductive support 1 to constitute the conductive member 10, the toner, the additive of the toner, etc. may adhere to the electric resistance adjusting layer 3 and the performance may deteriorate. Such a problem can be prevented by forming a surface layer on the electric resistance adjusting layer 3.

The resistance value of the surface layer 4 is formed so as to be larger than that of the electrical resistance adjusting layer 3, thereby avoiding voltage concentration and abnormal discharge (leakage) on the defect portion of the image carrier 6. However, if the resistance value of the surface layer 4 is too high, the charging ability and the transfer ability will be insufficient. Therefore, the difference in resistance value between the surface layer 4 and the electric resistance adjusting layer 3 is preferably 10 ³ Ωcm or less. .

  The surface layer 4 is formed on the resistance adjusting layer 3 by preparing the coating material by dissolving the constituent material of the surface layer 4 in an organic solvent, and performing various coating methods such as spray coating, dipping, and roll coating. About a film thickness, about 5-20 micrometers is desirable.

  As shown in FIG. 3, the conductive member 10 of the present invention has an outer peripheral surface of the image carrier 6 when the outer peripheral surface 51 of the gap holding members 5 and 5 comes into contact with the image carrier 6. And the outer peripheral surface of the conductive member 10 are provided with a difference in height between the outer peripheral surfaces of the gap holding members 5 and 5 with respect to the outer peripheral surface of the electrical resistance adjusting layer 3 so that a gap G is formed at a constant interval. ing. As described above, when the outer peripheral surfaces of the gap holding members 5 and 5 are in contact with the image carrier 6, there is a gap between the outer peripheral surface of the image carrier 6 and the outer peripheral surface of the electric resistance adjusting layer 3. If the height difference between the outer peripheral surfaces of the gap holding members 5 and 5 with respect to the outer peripheral surface of the electrical resistance adjusting layer 3 is provided so that the G is formed, the gap G between the image carrier 6 and the outer peripheral surface is accurate. Even if the electrical resistance adjustment layer 3 in which the gap holding members 5 and 5 are disposed changes due to environmental changes, it can follow the change in the electrical resistance adjustment layer 3. Therefore, gap variation can be suppressed.

  As shown in FIG. 2, the height difference between the outer peripheral surfaces of the gap holding members 5 and 5 with respect to the outer peripheral surface of the electrical resistance adjusting layer 3 is the gap holding member 5 installed on the conductive member 10. , 5 and the outer peripheral surface of the electric resistance adjusting layer 3 installed on the conductive support 1 are formed by integral processing by removal processing such as cutting and grinding. Thus, the difference in height of the outer peripheral surfaces of the gap holding members 5, 5 with respect to the outer peripheral surface of the electrical resistance adjusting layer 3 is different from the outer peripheral surfaces of the gap holding members 5, 5 installed on the conductive member 10. When formed by integral processing by removal processing such as cutting and grinding applied to the outer peripheral surface of the electric resistance adjusting layer 3 installed on the conductive support 1, the outer peripheral surface of the image carrier 6 And the fluctuation (shake) of the gap G formed between the outer peripheral surface of the electric resistance adjusting layer 3 and the accuracy of the gap G can be further increased.

  In the present invention, the conductive member 10 has a cylindrical shape. Thus, when the conductive member 10 has a cylindrical shape, the conductive member 10 can be rotationally driven. For this reason, continuous discharge from the same location is prevented and chemical deterioration of the surface due to energizing stress is prevented. Therefore, the life span can be increased.

  Note that the shapes of the conductive member 10 and the image carrier 6 of the present invention are not particularly limited, and the image carrier 6 can take either a belt shape or a cylindrical shape. The conductive member 10 can also have various shapes such as a blade shape and a cylindrical shape, but it is preferable that both are cylindrical. If both are always facing each other on the same surface, chemical deterioration of the surface due to energization stress occurs, but this deterioration can be reduced by rotating both of them in a cylindrical shape.

  In the present invention, the conductive member 10 is preferably a charging member. Thus, when the conductive member 10 is a charging member, the surface of the image carrier can be charged in a non-contact manner. For this reason, the charging member is prevented from being stained and the charging member is made of a hard material. By forming it, it is possible to achieve high accuracy, and therefore, uneven charging can be prevented.

  Next, as an example of the method for manufacturing the conductive member 10 described above, the resistance adjustment layer 3 is formed on the conductive support 1 by injection molding, and then the adhesive 2 is applied to both ends thereof, and the voids are formed. The holding members 5 and 5 are bonded and fixed. Thereafter, in order to reduce the variation in the stepped portions of the gap holding members 5 and 5 and the resistance adjustment layer 3, the removal of cutting, grinding, etc. is performed in the state where the gap holding members 5 and 5 and the resistance adjustment layer 3 are integrally formed. Finish the outer diameter by processing. Thereafter, the surface layer 4 is further formed on the electric resistance adjusting layer 3 in a state where the gap holding members 5 and 5 are protected, and the conductive member 10 is obtained.

  Further, since the chamfered shape 53 is formed by removal processing applied from the end surface portion (side surface) 52 of the gap holding member 5 toward the outer peripheral surface 51, the deformation portion rises due to processing resistance, and noise factors such as burrs are generated. Since the generation can be prevented more reliably, an accurate gap can be formed at the time of contact with the image carrier 6.

  Further, the chamfered shape 53 of the gap holding members 5 and 5 described above is an R shape or a shape having a curve. As described above, when the chamfered shape is an R shape or a shape having a curve, an accurate gap G can be formed at the time of contact with the image carrier 6, and damage to the image carrier 6 is reduced. be able to.

  For example, as shown in FIG. 5, the chamfered shape 53 is processed into a shape with a cutting tool, and the outer diameter processing of the gap holding members 5 and 5 and the electric resistance adjusting layer 3 is continuously performed as it is. The R shape is preferably set in relation to the outer diameter of the gap holding members 5 and 5 and the cutting allowance of the outer diameter. Further, when the R shape is set to R0.3 or less, the above-described end bulge and the effect of preventing the generation of burrs are small. Therefore, in the best mode, since the outer diameter of the gap retaining members 5 and 5 is φ12.8 → φ12.0 (cutting allowance φ0.8) and the journal diameter is φ6, the cutting depth is φ1.8 ( Machining in a shape with an outer diameter of φ10).

  Further, the chamfered shapes 53 of the gap holding members 5 and 5 are formed such that curved surfaces having different curvature radii are continuous. In this way, when curves having different radii of curvature in the chamfered shape 53 are continuously formed as curved surfaces, it is possible to form an accurate gap when contacting the image carrier 6, and to the image carrier 6. Damage can be reduced.

  For example, as shown in FIG. 6, two curved radii can be combined and a curved surface and an outer diameter can be continuously processed by a cutting tool. Since the curve has a continuous shape, the radius of curvature is arranged to be continuous at the curvature change point. By combining the curves as described above, the change in the direction of the curves can be reduced, and the shapes of the outer diameter portions and the end surfaces of the gap holding members 5 and 5 can be accurately finished.

  Further, the conductive member 10 described above is preferably a charging member. Such a conductive material can charge the surface of the image carrier 6 in a non-contact manner. For this reason, the charging member is prevented from being contaminated, and the charging member is made of a hard material so as to have high accuracy. Therefore, uneven charging can be prevented.

  Furthermore, the above-described conductive member (charging member) 10 is a detachable process cartridge (see 110 in FIG. 5) provided so as to be disposed close to the member to be charged. As described above, when the process cartridge is provided so that the conductive member (charging member) 10 is disposed close to the member to be charged, stable image quality can be obtained over a long period of time, and replacement can be performed by the user. Maintenance is possible and simplified.

  In the present invention, the image forming apparatus includes the process cartridge. Thus, with the image forming apparatus having the process cartridge according to the thirteenth aspect, an image with high reliability and high image quality can be obtained.

  As shown in FIG. 4, in the image forming apparatus of the present invention, a paper feed unit 22 at the lower part of the apparatus main body, an image forming unit having an image carrier 6 above it, and a paper discharge unit above it. A pair of paper discharge rollers 26 and 27 are provided, and an image is formed by the image forming unit corresponding to the left side surface of the transfer paper P fed from the paper feed unit 22, and the transfer paper P is discharged. The rollers 26 and 27 are discharged to the bin tray 20 or the discharge tray 21. The paper feed unit 22 is provided with trays 28 and 29 in two upper and lower stages, and a paper feed roller 30 is provided in each of the paper feed stages. Reference numeral 23 denotes a writing unit which irradiates light onto the uniformly charged surface of the image carrier 6 to write an image there. Further, on the upstream side of the image carrier 6 in the transfer paper conveyance direction, a registration roller pair 13 for correcting the skew of the transfer paper and matching the image on the image carrier 6 with the conveyance timing of the transfer paper is provided. Provided.

  Further, a fixing unit 25 is provided on the downstream side in the transfer paper conveyance direction with respect to the image carrier 6. As shown in FIG. 4, the image carrier 6 is provided in the image forming unit so as to be rotatable in the direction indicated by the arrow A, and a charging device (see 102 in FIG. 8) is disposed around the image carrier 6. A developing device (see 104 in FIG. 8) which visualizes the electrostatic latent image on the image carrier 6 written by the writing unit 23 on the surface charged by the charging device to form a toner image, and the developing device. A transfer conveyance belt 7 for transferring the toner image onto the transfer paper P, a cleaning device for removing residual toner remaining on the image carrier 6 after the transfer of the toner image (see 108 in FIG. 8), and an image carrier. A neutralizing lamp (not shown) for neutralizing unnecessary charges on 6 is provided. In this image forming apparatus, when the image forming operation is started, the image carrier 6 shown in FIG. 4 rotates in the direction of arrow A, and the surface thereof is neutralized by the neutralizing lamp and averaged to the reference potential. Next, the surface of the image carrier 6 is uniformly charged by a charging roller (see 102 in FIG. 8), and the charged surface is irradiated with light according to image information from the writing unit 23. An electrostatic latent image is formed there. When the latent image is moved to the position of the developing device (see 104 in FIG. 8) by rotating the image carrier 6 in the direction indicated by the arrow A, the toner adheres thereto by a developing sleeve (not shown). As a result, a toner image (visualized image) is formed.

  On the other hand, the transfer paper P is fed from one of the trays 28 and 29 of the paper feed unit 22 shown in FIG. 4 by the paper feed roller 30, and is temporarily stopped by the pair of registration rollers 13. The leading edge and the leading edge of the image on the image carrier 6 are conveyed at an accurate timing, and the toner image on the image carrier 6 is transferred onto the transfer paper P by the transfer conveyance belt 7. The transfer paper P is transported by the transfer transport belt 7, and is separated from the transfer transport belt 7 by the curvature separation by the waist of the transfer paper P by the driving roller unit 7a, and transported to the fixing unit 25, where heat and pressure are transferred. Is added to the transfer paper P, and the toner is discharged to a designated paper discharge location, that is, one of the paper discharge tray 21 and the bin tray 20. Thereafter, the residual toner remaining on the image carrier 6 rotates and moves to a cleaning position which is the next process, and is scraped off by a cleaning blade (see 108 in FIG. 8) of the cleaning device, and again in the next image forming process. Move on.

  In the present embodiment, the charging roller that embodies the conductive member 10 has been mainly described. However, the conductive member 10 according to the present invention is a charging member other than the charging roller, for example, It may be something like a blade. The conductive member 10 of the present invention may be a toner carrier or a transfer member.

Example 1
A resin composition comprising 50% by weight of ABS resin (Denka ABS GR-3000, manufactured by Denki Kagaku Kogyo) and 50% by weight of polyetheresteramide (IRGASTAT P18, manufactured by Ciba Specialty Chemicals) as the electrical resistance adjusting layer 3 And 5 parts by weight of a polycarbonate-glycidyl methacrylate-styrene-acryloylyl copolymer (Modiper CL440-G, manufactured by NOF Corporation) in 100 parts by weight of the resin composition, and then melt-kneaded and melt-kneaded them. A resin composition is formed, and this melt-kneaded composition is coated by injection molding on a 10 mm outer diameter conductive support (core shaft) made of nickel-plated sulfur free-cutting steel (SUM) to form an electric resistance adjusting layer. did. Then, a ring-shaped holding member 5 (having a discontinuous portion at one location) made of a high-density polyethylene resin (Novatech PP HY540, manufactured by Nippon Polychem Co., Ltd.) was adhered and disposed on both ends of the electrical resistance adjusting layer.

  Next, as shown in FIG. 2, after the chamfering of the end portions of the gap holding members 5, 5 by cutting, outer diameter machining was performed on the gap holding members 5, 5 and the electric resistance adjusting layer 3. Specifically, the chamfering shape 53 chamfered by C1 is processed by moving the cutting tool obliquely by 45 degrees from the end face portion 52 of the gap holding member 5, and the cutting tool is moved as it is, so that the outer diameter (maximum diameter) of the gap holding member 5 is increased. ) Was 12.7 mm and the outer diameter of the electric resistance adjusting layer 3 was 12.6 mm. And the edge part of the space | gap holding member 5 of the boundary side of the space | gap holding member 5 and the electrical resistance adjustment layer 3 was set to C0.05. The gap holding member 5 on the opposite side is also C0.05, and after chamfering the electric resistance adjusting layer 3 and the gap holding member 5, the outer diameter of the gap holding member 5 is processed, and the end on the end face side of the gap holding member 5 is formed. Chamfered with C1.

  Next, an acrylic silicone resin (3000 VH-P, manufactured by Kawakami Paint Co., Ltd.), an isocyanate curing agent (manufactured by Kawakami Paint Co., Ltd.), and carbon black (30% by weight with respect to the total solid content) The surface composition 4 having a thickness of about 10 μm was formed by spray coating the resin composition consisting of Thereafter, the coating resin was heated and cured in an oven at 80 ° C. for 1 hour to obtain a conductive member 10 (see FIG. 1).

(Example 2)
A resin composition comprising 50% by weight of ABS resin (Denka ABS GR-3000, manufactured by Denki Kagaku Kogyo) and 50% by weight of polyetheresteramide (IRGASTAT P18, manufactured by Ciba Specialty Chemicals) as the electrical resistance adjusting layer 3 And 5 parts by weight of a polycarbonate-glycidyl methacrylate-styrene-acryloylyl copolymer (Modiper CL440-G, manufactured by NOF Corporation) in 100 parts by weight of the resin composition, and then melt-kneaded and melt-kneaded them. A resin composition is formed, and this melt-kneaded composition is coated by injection molding on a 10 mm outer diameter conductive support (core shaft) made of nickel-plated sulfur free-cutting steel (SUM) to form an electric resistance adjusting layer. did. Then, a ring-shaped holding member 5 (having a discontinuous portion at one location) made of a high-density polyethylene resin (Novatech PP HY540, manufactured by Nippon Polychem Co., Ltd.) was adhered and disposed on both ends of the electrical resistance adjusting layer.

  Next, as shown in FIG. 5, after the chamfering of the end portions of the gap holding members 5 and 5 by cutting, outer diameter processing was performed on the gap holding members 5 and 5 and the electric resistance adjusting layer 3. Specifically, the chamfered shape 53 chamfered by moving the cutting tool into the R1 shape from the end face portion 52 of the gap holding member 5 is processed, and the cutting tool is moved as it is to set the outer diameter (maximum diameter) of the gap holding member 5 to 12. The outer diameter of the electric resistance adjusting layer 3 was simultaneously finished to 12.6 mm. And the edge part of the space | gap holding member 5 of the boundary side of the space | gap holding member 5 and the electrical resistance adjustment layer 3 was set to R0.05. The gap holding member 5 on the opposite side is also R0.05, and after chamfering the electric resistance adjusting layer 3 and the gap holding member 5, the outer diameter of the gap holding member 5 is processed, and the end on the end face side of the gap holding member 5 is processed. Chamfered with R1.

  Next, an acrylic silicone resin (3000 VH-P, manufactured by Kawakami Paint Co., Ltd.), an isocyanate curing agent (manufactured by Kawakami Paint Co., Ltd.), and carbon black (30% by weight with respect to the total solid content) The surface composition 4 having a thickness of about 10 μm was formed by spray coating the resin composition consisting of Thereafter, the coating resin was heated and cured in an oven at 80 ° C. for 1 hour to obtain a conductive member 10.

(Comparative example)
As an electrical resistance adjusting layer, 50% by weight of ABS resin (Denka ABS GR-3000, manufactured by Denki Kagaku Kogyo) and 50% by weight of polyetheresteramide (IRGASTAT P18, manufactured by Ciba Specialty Chemicals) are blended to form a resin composition. In addition, 5 parts by weight of a polycarbonate-glycidyl methacrylate-styrene-acryloylyl copolymer (Modiper CL440-G, manufactured by NOF Corporation) was blended with 100 parts by weight of the resin composition, and then these were melt-kneaded and melt-kneaded resin. This melt-kneaded composition was coated on a 10 mm outer conductive support (core shaft) made of nickel-plated sulfur free-cutting steel (SUM) by injection molding to form an electric resistance adjusting layer. . Then, a ring-shaped holding member 5 (having a discontinuous portion at one location) made of a high-density polyethylene resin (Novatech PP HY540, manufactured by Nippon Polychem Co., Ltd.) was adhered and disposed on both ends of the electrical resistance adjusting layer.

Next, simultaneous finishing was performed by cutting so that the outer diameter (maximum diameter) of the gap holding member was 12.7 mm and the outer diameter of the electric resistance adjusting layer was 12.6 mm. And the end surface part of a space | gap holding member, and
Each end portion on the boundary side between the gap holding member and the electric resistance adjusting layer was not chamfered and formed into a square shape. Next, an acrylic silicone resin (3000 VH-P, manufactured by Kawakami Paint Co., Ltd.), an isocyanate curing agent (manufactured by Kawakami Paint Co., Ltd.), and carbon black (30% by weight with respect to the total solid content) The surface composition 4 having a thickness of about 10 μm was formed by spray coating the resin composition consisting of Thereafter, the coating resin was heated and cured in an oven at 80 ° C. for 1 hour to obtain a conductive member 10 shown in FIG. The gap holding member 5 of the conductive member 10 has a burr 55 at the end on the end face 52 side and a raised portion 56 at the end on the opposite side.

  In addition, the conditions used for the cutting in Examples 1 and 2 and the comparative example described above are a cutting tool with an inclined tool (65 ° tilt) and 6R, and the processing conditions are a rotation speed of 3000 rpm and an outer diameter of the cutting allowance. The feed rate is 0.8 mm and the feed rate is 0.2 mm / rev. And processing was carried out by NC program.

(Test 1)
The conductive members obtained in Examples 1 and 2 and the comparative example are mounted on an image forming apparatus (see FIG. 5) as a charging member, and applied voltages are DC = −800 V, AC = 2.4 kVpp ( The frequency was set to 2 kHz, and 300,000 copies were made to observe charging unevenness, a change in the gap amount between the charging member and the image carrier, and the state of the gap holding member and the image carrier. The evaluation environment was 23 ° C. and 60% RH. The evaluation results are shown in the following Table 1.

However, the evaluation criteria in Table 1 are:
○: Charging unevenness due to insufficient charge amount does not occur,
Δ: Slight unevenness due to insufficient charge amount is observed,
×: Unacceptable charging unevenness due to insufficient charge amount,
It was.

  As shown in Table 1, in Examples 1 and 2, stable void amount and chargeability were exhibited in the initial state and after copying 300,000 sheets. However, in the comparative example, the void amount increased in the initial state, and the charge amount Uneven charging occurred due to lack. This is because the bulge 55 generated at the end-shaped raised portion 56 of the gap holding member and the cut portion interferes with the contact portion with the image carrier 6 and the gap is increased. In addition, after copying 300,000 sheets, charging unevenness caused by current leakage occurred. Peeling of the insulating layer at the contact portion between the image carrier and the gap holding member was observed. This is considered to be because the burrs at the ends of the gap holding members 5 and 5 were damaged.

It is sectional drawing of the electroconductive member which shows one embodiment of this invention. It is explanatory drawing which shows the method of forming the 1st chamfering shape of the space | gap holding member which shows one embodiment of this invention. 1 is an explanatory diagram of an image forming apparatus according to an embodiment of the present invention. 1 is an explanatory diagram of an image forming apparatus according to an embodiment of the present invention. It is explanatory drawing which shows the method of forming the 2nd chamfering shape of the space | gap holding member which shows one embodiment of this invention. It is explanatory drawing which shows the method of forming the 3rd chamfering shape of the space | gap holding member which shows one embodiment of this invention. It is an enlarged view of the space | gap holding member when not chamfering. It is an explanatory view of an electrophotographic image forming apparatus having a conventional charging roller. It is sectional drawing which shows an example of the conventional charging member.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Conductive support body 2 Adhesive 3 Electric resistance adjustment layer 4 Surface layer 5 Gap holding member 6 Image carrier G Gap 10 Conductive member 51 Outer peripheral surface 53 Chamfered shape

Claims (10)

  A conductive support; an electrical resistance adjustment layer formed on the conductive support; and the electrical resistance adjustment layer and the image carrier in contact with the image carrier so as to maintain a certain gap. A conductive member having a gap holding member formed at both ends of the resistance adjustment layer, wherein a chamfered shape is formed at an end portion of the outer circumferential surface of the gap holding member in contact with the image carrier. Conductive member.   The conductive member according to claim 1, wherein the chamfered shape of the gap holding member is an R shape or a shape having a curve.   The conductive member according to claim 1 or 2, wherein the chamfered shape of the gap holding member is formed such that curved surfaces having different radii of curvature are continuous.   When the outer peripheral surface of the gap holding member is in contact with the image carrier, the electric gap is formed so that a gap is formed between the outer peripheral surface of the image carrier and the outer peripheral surface of the conductive member. The conductive member according to claim 1, wherein a difference in height of the outer peripheral surface of the gap holding member with respect to the outer peripheral surface of the resistance adjusting layer is provided.   The difference in height of the outer peripheral surface of the gap holding member with respect to the outer peripheral surface of the electric resistance adjusting layer is such that the outer peripheral surface of the gap holding member installed on the conductive support and the conductive support are installed on the conductive support. 5. The conductive member according to claim 4, wherein the conductive member is formed by an integrated process by a removal process such as a cutting process or a grinding process applied to the outer peripheral surface of the electrical resistance adjusting layer.   6. The chamfered shape of the gap holding member is formed by a removal process such as a cutting process or a grinding process performed from a side surface of the gap holding member toward the outer peripheral surface. The conductive member according to any one of the above.   The conductive member according to claim 1, wherein the conductive member has a cylindrical shape.   The conductive member according to claim 1, wherein the conductive member is a charging member.   9. A process cartridge, wherein the charging member according to claim 8 is provided so as to be disposed close to a member to be charged.   An image forming apparatus comprising the process cartridge according to claim 9.

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