JP2006350093A - Conductive member and process cartridge having the same, and image forming apparatus having the process cartridge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a conductive member that can uniformly charge the surface of an image carrier by maintaining a stable gap between the image carrier and the conductive member, even if the conductive member is used initially and over a long period. <P>SOLUTION: The conductive member 1 has the conductive base 1, the electrical resistance adjusting layer 3 formed on the conductive base 1, and gap-holding members 5, 6 which are formed at both ends of the electrical resistance adjusting layer 3 abutting against the image carrier in such a manner that the electric resistance adjusting layer 3 and the image carrier maintain the specified gap, in which the electric resistance adjusting layer 3 is fixed by an adhesive 2 to the conductive base 1. The adhesive 2 is preferably a conductive adhesive containing conductive particles selected from gold, silver, nickel, and carbon. <P>COPYRIGHT: (C)2007,JPO&INPIT

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. 5 is an explanatory view of an electrophotographic image forming apparatus having a conventional charging roller.

  In FIG. 5, 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 image carrier 101 by the irradiation of the image light, that is, An electrostatic latent image is formed. When the portion of the image carrier 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 to a portion of the image carrier 101 on which the toner image is formed by a registration roller (not shown) at a predetermined timing, and overlaps the toner image. Then, after the toner image is transferred to the recording paper 107 by the transfer roller 106, the recording paper 107 is separated from the image carrier 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 image carrier 101 is cleaned by the cleaning device 108, and residual charges are removed by a quenching lamp (not shown), so that the next image forming process is performed. Prepared for.

A conventional charging method using a charging roller includes a contact charging method in which a charging roller is brought into contact with an image carrier (see Patent Documents 1 and 2). ,
(1) The substance constituting the charging roller oozes out from the charging roller, and this adheres to the surface of the object to be charged and leaves a charging roller mark.
(2) When an AC voltage is applied to the charging roller, the charging roller that is in contact with the member to be charged vibrates, so that a charging noise is generated.
(3) Since the toner on the image carrier adheres to the charging roller (particularly, the above-mentioned oozing out makes toner adhesion more likely), so that the charging performance of the charging roller is reduced.
(4) the substance constituting the charging roller adheres to the image carrier, and
(5) The charging roller is permanently deformed when the image carrier is stopped for a long time.
There was a problem.

  As a technique for solving such a problem, a charging device using a proximity charging method (see Patent Documents 3 and 4) in which a charging roller is brought close to an image carrier has been proposed. In the charging device using the proximity charging method, the image bearing member is charged by applying a voltage to the charging roller with the charging roller facing the image bearing member at a closest distance (50 to 300 μm). It is a thing. In the charging device using the proximity charging method, the charging roller and the image carrier are not in contact with each other. Therefore, the substance constituting the charging roller, which has been a problem in the conventional charging device using the contact charging method, is the image carrier. There are no problems such as adhering to the surface and permanent deformation when the image carrier is stopped for a long time. Further, in the charging device using the proximity charging method, the toner adhering to the charging roller is reduced, so that the toner or the like on the image carrier is less likely to adhere to the charging roller. Therefore, it can be said that the charging device using the proximity charging method is an excellent charging device.

  In the contact charging method, in order to uniformly charge the image carrier, the charging roller needs to be in uniform contact with the image carrier. Therefore, the charging roller generally used in the proximity charging method. Has a configuration in which an electric resistance adjusting layer is coated around the cored bar. However, since the coefficient of linear expansion differs greatly between the electric resistance adjusting layer and the conductive support, the interface between the electric resistance adjusting layer and the conductive support peels off in a low-temperature or high-temperature environment, resulting in misalignment. . Due to this misalignment, a gap is generated between the electric resistance adjusting layer and the conductive support in the firing process in the manufacturing stage or in long-term use. When such a gap is generated, there is a problem that the strength of the electric resistance adjusting layer is lowered or the resistance value fluctuates due to the slight vibration when the AC voltage is applied. In particular, when the strength is reduced in the weld portion generated during molding, there is a problem that cracks are generated in the weld portion due to electrical / mechanical stress during use and volume variation with time and environment. In addition, there is a problem that the resistance variation in the gap generation portion causes a defect of partial image defect.

FIG. 6 is a cross-sectional view of a conventional conductive member (charging roller). As shown in FIG. 6, misalignment between the conductive support 301 and the electrical resistance adjustment layer 303 can be prevented by measures such as providing steps at both ends of the conductive support 301. In such a case, when the electric resistance adjusting layer 303 is coated around the conductive support 301, the molding strain is concentrated in the vicinity of the stepped portion of the conductive support 301. There has been a problem that a crack is generated in the resistance adjustment layer 303 or a stable gap cannot be maintained between the resistance adjustment layer 303 and the image carrier due to fluctuations in the outer diameter of the electric resistance adjustment layer 303. In FIG. 6, reference numeral 305 denotes a gap holding member, and 304 denotes a surface layer.
JP-A 63-149668 JP-A-1-267667 Japanese Patent Laid-Open No. 3-240076 JP-A-4-358175

  The present invention aims to solve this problem.

  That is, the present invention can maintain a stable gap between the image carrier and the conductive member even when used for an initial period and for a long period of time, and can uniformly charge the surface of the image carrier. It is an object of the present invention to provide a conductive member having improved durability, a process cartridge having the conductive member, and an image forming apparatus having the process cartridge.

  In order to achieve the above object, the invention described in claim 1 includes a conductive support, an electrical resistance adjustment layer formed on the conductive support, the electrical resistance adjustment layer, and the image carrier. A conductive member having 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, wherein the electric resistance adjusting layer is a conductive support. It is the electroconductive member characterized by being fixed to this with the adhesive agent.

  The invention described in claim 2 is characterized in that, in the invention described in claim 1, the adhesive is a conductive adhesive.

  The invention described in claim 3 is the invention described in claim 2, characterized in that the conductive adhesive contains conductive particles selected from gold, silver, nickel and carbon. It is.

  The invention described in claim 4 is characterized in that, in the invention described in any one of claims 1 to 3, the adhesive is previously applied to a conductive support. is there.

  The invention described in claim 5 is characterized in that, in the invention described in any one of claims 1 to 4, the surface of the conductive support is roughened. .

  The invention described in claim 6 is the invention described in any one of claims 1 to 5, wherein the conductive support and the gap holding member are fixed by the adhesive. It is a feature.

  The invention described in claim 7 is characterized in that, in the invention described in claim 6, the adhesive surface of the gap holding member is surface-treated with an active gas in advance.

  According to an eighth aspect of the present invention, when the outer peripheral surface of the gap holding member abuts on the image carrier, a constant interval is provided between the outer peripheral surface of the image carrier and the outer peripheral surface of the conductive member. A 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 so that a void is formed.

  According to the ninth 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 the outer peripheral surface of the gap holding member installed on the conductive support. , And an outer peripheral surface of the electric resistance adjusting layer installed on the conductive support, and is formed by integral processing by removal processing such as cutting processing or grinding processing.

  The invention described in claim 10 is the invention described in any one of claims 1 to 9, wherein a surface layer for preventing adhesion of toner is formed on the electric resistance adjusting layer. It is what.

  The invention described in claim 11 is the invention described in claim 10, wherein the resin constituting the surface layer is an acrylic silicon resin, a fluororesin, a silicone resin, an acrylic resin, a polyamide resin, a polyurethane resin, or a polyester resin. And a resin selected from polyvinyl butyral resins.

  The invention described in claim 12 is the invention described in any one of claims 1 to 11, wherein the conductive member has a cylindrical shape.

  The invention described in claim 13 is the invention described in any one of claims 1 to 12, characterized in that the conductive member is a charging member.

  According to a fourteenth aspect of the present invention, there is provided a process cartridge characterized in that the charging member according to the thirteenth aspect is provided so as to be disposed close to a member to be charged.

  According to a fifteenth aspect of the present invention, there is provided an image forming apparatus having the process cartridge according to the fourteenth aspect.

  According to the first aspect of the present invention, since the electrical resistance adjustment layer is fixed to the conductive support with an adhesive, the generation of a gap between the conductive support and the electrical resistance adjustment layer is prevented. In addition, it is possible to prevent a decrease in strength of the electrical resistance adjusting layer and a change in electrical resistance value due to this, and even if used for an initial period and a long period of time, the image carrier and the conductive member It is possible to provide a conductive member that can maintain a stable gap therebetween and uniformly charge the surface of the image bearing member and also has improved durability.

  According to the second and third aspects of the invention, since the adhesive is a conductive adhesive, it is possible to prevent an increase in electrical resistance of the conductive member.

  According to the invention described in claim 4, since the adhesive is applied to the conductive support in advance, it can be easily bonded over the entire interface between the conductive support and the electric resistance adjusting layer. it can.

  According to the invention described in claim 5, since the surface of the conductive support is roughened, the conductive support and the electric resistance adjusting layer can be bonded more firmly.

  According to the invention described in claim 6, since the conductive support and the gap holding member are fixed by the adhesive, the gap holding member can be easily conducted by avoiding the application of the adhesive twice. It can be adhesively fixed to the adhesive support.

  According to the seventh aspect of the present invention, since the bonding surface of the gap holding member is previously surface-treated with an active gas, the conductive support and the gap holding member are bonded more firmly. be able to.

  According to the eighth aspect of the present invention, when the outer peripheral surface of the gap holding member comes into contact with the image carrier, the gap is constant between the outer peripheral surface of the image carrier and the outer peripheral surface of the conductive member. Since the gap 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 so that a gap having a gap is formed, the gap between the gap and the image carrier is accurately maintained constant. In addition, even if the electrical resistance adjustment layer in which the gap holding member is arranged changes in size due to environmental fluctuations, it can follow the change in the electrical resistance adjustment layer, and thus suppress gap fluctuations. it can.

  According to the ninth 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 the outer peripheral surface of the gap holding member installed on the conductive support. And the outer peripheral surface of the electric resistance adjusting layer installed on the conductive support are formed by integral processing by removal processing such as cutting and grinding, so that the gap holding member and the electric The difference in height with the resistance adjustment layer can be formed by integrated processing. For this reason, the fluctuation (shake) of the gap G formed between the outer peripheral surface of the image carrier and the outer peripheral surface of the electric resistance adjustment layer is reduced. The accuracy of the gap G can be further increased by reducing the size.

  According to the eighth and ninth aspects of the present invention, since the surface layer for preventing adhesion of toner is formed on the electric resistance adjusting layer, a conductive member having excellent toner fixing property can be obtained.

  According to the invention described in claim 10, since the conductive member has a cylindrical shape, the conductive member can be rotationally driven. It is possible to reduce the chemical deterioration of the surface due to, so that the longevity can be achieved.

  According to the eleventh aspect of the invention, since the conductive member 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 charged. By forming the member with a hard material, it is possible to achieve high accuracy, and therefore, uneven charging can be prevented.

  According to the twelfth aspect of the present invention, since the charging member according to the eleventh aspect of the present invention 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. In addition, the replacement can be simplified by user maintenance.

  According to the thirteenth aspect of the invention, since the image forming apparatus having the process cartridge according to the twelfth aspect of the invention is formed, 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 (charging roller) showing an embodiment of the present invention. FIG. 2 is an explanatory view showing a method of forming a conductive member (charging roller) according to an embodiment of the present invention. FIG. 3 is a schematic diagram showing a state in which a conductive member (charging roller) is arranged on the image carrier. FIG. 4 is an explanatory diagram of an image forming apparatus showing an embodiment of the present invention.

  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.

  As described above, when the electrical resistance adjusting layer 3 is fixed to the conductive support 1 with the adhesive 2, the generation of a gap between the conductive support 1 and the electrical resistance adjusting layer 3 is prevented. It is possible to prevent a decrease in strength of the electrical resistance adjusting layer 3 and fluctuation of the electrical resistance value due to this, and therefore, even when used for an initial period and a long period of time, the image carrier (see 6 in FIG. 3). The conductive member can maintain a stable gap (see G in FIG. 3) between the conductive member 10 and the conductive member 10 to uniformly charge the surface of the image bearing member and improve durability. 10 can be provided.

  As shown in FIG. 3, the conductive member (charging 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. By applying a voltage to the charging member in this state, the image carrier can be charged. 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.

  The adhesive 2 is preferably a conductive adhesive. And the said conductive adhesive contains the electroconductive particle chosen from gold | metal | money, silver, nickel, and carbon, for example. The base resin of the conductive adhesive is preferably an epoxy resin, a polyurethane resin, a silicone resin, or the like. The adhesive 2 can be used in both one-part and two-part forms, and is not particularly limited, but the one-part type has higher workability.

  When the adhesive 2 is not conductive, the resistance of the conductive member 10 is increased, so that the charging ability and transfer ability during use are insufficient. Therefore, when the adhesive 2 is a conductive adhesive, an increase in electrical resistance of the conductive member 10 can be prevented.

  The adhesive 2 is preferably applied to the conductive support 1 in advance. Thus, when the adhesive 2 is applied to the conductive support 1 in advance, it can be easily bonded over the entire interface between the conductive support 1 and the electric resistance adjusting layer 3. Therefore, in the manufacturing stage of the conductive member 10 and when the conductive member 10 is used for a long period of time, the occurrence of separation / gap between the conductive support 1 and the electric resistance adjusting layer 3 is avoided. Therefore, a decrease in strength of the electrical resistance adjusting layer 3 and fluctuations in the electrical resistance value do not occur, so that there are no mechanical or electrical stresses during use and cracks due to volume fluctuations over time or in the environment. It becomes difficult to occur.

  The surface of the conductive support 1 is preferably roughened. As described above, when the surface of the conductive support 1 is roughened, the conductive support 1 and the electric resistance adjusting layer are more strongly bonded by the synergistic effect of adhesion between the roughened surface and the adhesive 2. 3 can be bonded. Examples of the surface roughening treatment include sand blast treatment and zinc phosphate treatment.

  The conductive support 1 and the gap holding members 5 and 5 are fixed by the adhesive 2. As described above, when the conductive support 1 and the gap holding members 5 and 5 are fixed by the adhesive 2, the gap holding members 5 and 5 can be easily conductive by avoiding the application of the adhesive twice. The adhesive support 1 can be adhered and fixed.

  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 gap holding members 5 and 5 are made of an insulating resin having a volume resistivity of 10 ¹³ Ω · cm or more. The reason why such an insulating resin is required is to eliminate generation of a short current flowing between the image bearing member and the image bearing member. A necessary characteristic of the gap holding members 5 and 5 is that the gap with the image carrier 6 is stably formed over the environment and for a long time (time). Is preferably a material with low hygroscopicity and wear resistance. Further, since the gap holding members 5 and 5 are in contact with and slide on the image carrier 6 to which toner and toner additives are difficult to adhere, it is also important that the image carrier 6 is not worn. The material constituting the gap retaining members 5 and 5 is appropriately selected according to various conditions, but is preferably polyethylene (PE), polypropylene (PP), polymethyl methacrylate (PMMA), polystyrene ( PS), a resin such as polystyrene copolymer (AS, ABS), or a resin such as PC, polyurethane, or fluororesin. The gap holding members 5 and 5 in the present invention are molded by molding such a resin.

In the present invention, the volume resistivity of the electric resistance adjusting layer 3 is preferably 10 ⁶ to 10 ⁹ Ωcm. When the volume resistivity of the electric resistance adjusting layer 3 exceeds 10 ⁹ Ωcm, the charging ability and the transfer capability are insufficient, and when the volume resistivity of the electric resistance adjusting layer 3 is less than 10 ⁶ , the image carrier. Leakage due to voltage concentration on the entire 6 occurs. However, when the volume resistivity of the electric resistance adjusting layer 3 is 10 ⁶ to 10 ⁹ Ωcm as in the present invention, sufficient charging ability and transfer ability can be secured, and power to the image carrier 6 can be secured. Generation of abnormal discharge due to concentration can be prevented, and a uniform image can be obtained for them.

  The resin used for the electrical resistance adjusting layer 3 is not particularly limited, but polyethylene (PE), polypropylene (PP), polymethyl methacrylate (PMMA), polystyrene (PS), polystyrene copolymer (AS, ABS) and the like, or thermoplastic resins such as PC, polyurethane and fluororesin. These resins are preferable because of good processability. As the polymer type ion conductive material dispersed in the resin, a polymer compound containing polyether ester amide is preferable. Since the polyether ester amide is an ion conductive polymer material, it is uniformly dispersed and immobilized at a molecular level in the matrix polymer. Therefore, there is no variation in electrical 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. Further, since polyether ester amide is a polymer material, bleeding out hardly occurs. In order to make the electric resistance value a desired value, the blending amount thereof is preferably 30 to 70% by weight of the thermoplastic resin and 70 to 30% by weight of the polymer type ion conductive agent. The thickness of the electrical resistance adjusting layer 3 made of such a resin is preferably 100 μm or more and 500 μm or less. When the thickness of the electric resistance adjusting layer 3 is less than 100 μm, it becomes too thin and abnormal discharge due to leakage occurs, and when the thickness of the electric resistance adjusting layer 3 exceeds 500 μm, it becomes too thick to maintain surface accuracy. It becomes difficult.

  A semiconductive resin composition composed of such materials can be easily produced by melt-kneading a mixture of each material with a biaxial kneader, a kneader or the like. The electric resistance adjusting layer 3 can be easily formed on the conductive support 1 by covering the conductive support 1 with the semiconductive resin composition by means of extrusion molding or injection molding. Can do. When the conductive member 10 is formed by forming only the electric resistance adjusting layer 3 on the conductive support 1, the toner and the additive of the toner may adhere to the electric resistance adjusting layer 3 and the performance may deteriorate. In the present invention, since the surface layer 4 is formed on the electric resistance adjusting layer 3, the toner and the additive added to the toner are prevented from adhering to the surface of the conductive member for a long time. be able to.

  As shown in FIG. 3, the conductive member (charging roller) 10 of the present invention has an image bearing member 6 when the outer peripheral surfaces of the gap holding members 5 and 5 are in contact with the image bearing member 6. The 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 such that a gap G is formed at a constant interval between the outer peripheral surface of the conductive member 10 and the outer peripheral surface of the conductive member 10. A difference is provided. 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, a surface layer 4 for preventing adhesion of toner is formed on the electric resistance adjusting layer 3. As described above, when the surface layer 4 for preventing adhesion of toner is formed on the electric resistance adjusting layer 3, the conductive member 10 having excellent toner fixing property can be obtained.

In the present invention, the volume resistivity of the surface layer 4 is made larger than the volume resistivity of the electrical resistance adjusting layer 3. As described above, when the volume resistivity of the surface layer 4 is larger than the volume resistivity of the electric resistance adjusting layer 3, it is possible to prevent voltage concentration and abnormal discharge from occurring on the image carrier defect portion. However, if the electric resistance value of the surface layer 4 is too high, the charging ability and the transfer ability will be insufficient. Therefore, the difference in electric resistance value between the surface layer 4 and the electric resistance adjusting layer 3 should be 10 ³ or less. preferable. The material forming the surface layer 4 is preferably a resin such as a fluorine resin, a silicone resin, a polyamide resin, or a polyester. Since these resins are excellent in non-adhesiveness, they are preferable in terms of preventing sticking of toner. Moreover, since this resin is electrically insulative, the electrical resistance of the surface layer 4 can be adjusted by dispersing various conductive materials in the resin. The surface layer 4 is formed on the electric resistance adjusting layer 3 by preparing a paint by dissolving the resin material constituting the surface layer 4 in an organic solvent, and applying the paint by means of spray coating, dipping, roll coating or the like. Do. The film thickness of the surface layer 4 is preferably 10 to 30 μm.

  The resin constituting the surface layer 4 can be either one-component or two-component, but if a two-component paint is used in combination with a curing agent, the environmental resistance and non-stickiness can be improved. . In the case of a two-component paint, a method of crosslinking and curing the resin by heating the coating film is common. However, if the electrical resistance adjusting layer 3 is a thermoplastic resin, it cannot be heated at a high temperature. As the two-component paint, it is preferable to use a main agent having a hydroxyl group in the molecule and an isocyanate resin that causes a crosslinking reaction with the hydroxyl group. When an isocyanate resin is used, a crosslinking / curing reaction occurs at a relatively low temperature of 100 ° C. or lower. As a result of studying from the non-adhesiveness of the toner, the present inventors confirmed that the resin is a silicone-based resin having a high non-adhesive property of the toner, and in particular, an acrylic silicone resin having an acrylic skeleton in the molecule. It was found to be good.

  Since the electrical characteristics (electric resistance value) of the conductive member are important, it is necessary to make the surface layer 4 conductive. The conductive surface layer 4 is formed by dispersing a conductive agent in the resin material constituting the surface layer 4. The conductive agent is not particularly limited, but conductive carbon such as ketjen black EC and acetylene black, rubber carbon such as SAF, ISAF, HAF, FEF, GPF, SRF, FT and MT, oxidation treatment, etc. Carbon for color, pyrolytic carbon, indium-doped tin oxide (ITO), tin oxide, titanium oxide, zinc oxide, copper, silver, germanium, and metal oxides, polyaniline, polypyrrole, polyacetylene, etc. Examples include conductive polymers. In addition, as the conductivity imparting material, there are also ionic conductive materials, inorganic ionic conductive materials such as sodium perchlorate, lithium perchlorate, calcium perchlorate, and lithium chloride, and further modified fatty acid dimethyl ammonium ethosulphate. And organic ionic conductive materials such as ammonium stearate acetate and lauryl ammonium acetate.

  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.

  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.

  In the present invention, the shapes of the conductive member 10 and the image carrier 6 are not particularly limited, and the image carrier 6 can take either a belt shape or a cylindrical shape. The conductive member 10 can take various shapes such as a circular cross section (cylindrical shape), an elliptical cross section, and a blade shape in which the cylindrical shape is flattened, and both are preferably cylindrical. If they are always facing each other on the same surface, chemical deterioration of the surface due to energization stress will occur, but if they are driven to rotate in a cylindrical shape, continuous discharge from the same location can be prevented. Furthermore, chemical degradation of the surface due to energization stress can be reduced. For example, as shown in FIG. 3, the rotation direction of the conductive member 10 can be selected in the same direction as the image carrier 6 or in the opposite direction. It is also possible to make a peripheral speed difference from the image carrier 6 (rotate faster than image carrier 6 or rotate slower). Further, intermittent rotation with respect to the rotation of the image carrier 6 is possible within a range where the function is not impaired. 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. This is because when the gap G becomes large, it is necessary to increase the voltage application condition to the conductive member 10, and electrical deterioration and abnormal discharge of the image carrier 6 are likely to occur.

  The conductive member 10 according to any one of claims 1 to 11 is preferably a charging member. Such a conductive material can charge the surface of the image carrier in a non-contact manner. For this reason, the charging member can be prevented from being contaminated, and the charging member can be made of a hard material so as to have high accuracy. Therefore, uneven charging can be prevented.

  The conductive member (charging member) 10 described in claim 12 is a detachable process cartridge (refer to 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 according to the twelfth aspect is disposed close to the member to be charged, stable image quality can be obtained over a long period of time. In addition, user replacement is possible and simplified.

  In the present invention, an image forming apparatus having the process cartridge (refer to 110 in FIG. 5) according to claim 13 is provided. 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. 5) is disposed around the image carrier 6. A developing device (see 104 in FIG. 5) that 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. 5), 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. 5), 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. 5) by rotating the image carrier 6 in the direction indicated by the arrow A, toner adheres to the latent image 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. 5) 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
The surface of a straight rod-shaped body made of stainless steel with an outer diameter of 8 mm is subjected to a roughening treatment by sandblasting, and then a one-component epoxy resin-based conductive adhesive (3301, manufactured by ThreeBond Co., Ltd.) is applied to make the surface conductive. A support (core shaft) was used. Then, 50% by weight of ABS resin (Denka ABS GR-0500, manufactured by Denki Kagaku Kogyo Co., Ltd.) and 50% by weight of polyetheresteramide (IRGASTAT P18, manufactured by Ciba Specialty Chemicals Co., Ltd.) are blended to form a resin composition (volume specific) Resistance: 2 × 10 ⁸ Ωcm), and this resin composition was coated on the conductive support by injection molding to form an electric resistance adjusting layer. Next, the inner surface of the ring-shaped gap holding member made of high-density polyethylene resin (Novatech HD HY540, manufactured by Nippon Polychem Co., Ltd.), that is, the adhesive surface is subjected to surface treatment by corona discharge, and the gap holding member is subjected to the electric resistance adjusting layer. The gap holding member and the conductive support are bonded with a conductive adhesive, and then the outer diameter (maximum diameter) of the gap holding member is set to 12 by cutting as shown in FIG. The outer diameter of the resistance adjusting layer was 12.00 mm. Subsequently, a resin composition comprising an acrylic silicone resin (3000 VH-P, manufactured by Kawakami Paint Co., Ltd.), an isocyanate curing agent, and carbon black (35% by weight with respect to the total solid content) is formed on the surface of the electric resistance adjusting layer. A surface layer having a film thickness of about 10 μm was formed from an object (surface resistance: 2 × 10 ⁹ Ω), and a conductive member was obtained through a firing step.

(Example 2)
After the surface of a straight rod-shaped body made of stainless steel with an outer diameter of 8 mm is roughened by zinc phosphate treatment, a one-component modified urethane resin conductive adhesive (3302B, manufactured by ThreeBond Co., Ltd.) is applied. Thus, a conductive support (core shaft) was obtained. Then, 50% by weight of ABS resin (Denka ABS GR-0500, manufactured by Denki Kagaku Kogyo Co., Ltd.) and 50% by weight of polyetheresteramide (IRGASTAT P18, manufactured by Ciba Specialty Chemicals Co., Ltd.) are blended to form a resin composition (volume specific) Resistance: 2 × 10 ⁸ Ωcm), and this resin composition was coated on the conductive support by injection molding to form an electric resistance adjusting layer. Next, the inner surface of the ring-shaped gap holding member made of high-density polyethylene resin (Novatec HD HY540, manufactured by Nippon Polychem), that is, the adhesive surface is subjected to surface treatment by plasma irradiation with oxygen gas, and the gap holding member is electrically treated. After extrapolating to both ends of the resistance adjustment layer and bonding the gap holding member and the conductive support with a conductive adhesive, the outer diameter (maximum diameter) of the gap holding member is cut by cutting as shown in FIG. ) Was set to 12.12 mm, and the outer diameter of the resistance adjusting layer was set to 12.00 mm. Subsequently, a resin composition comprising an acrylic silicone resin (3000 VH-P, manufactured by Kawakami Paint Co., Ltd.), an isocyanate curing agent, and carbon black (35% by weight with respect to the total solid content) is formed on the surface of the electric resistance adjusting layer. A surface layer having a film thickness of about 10 μm was formed from an object (surface resistance: 2 × 10 ⁹ Ω), and a conductive member was obtained through a firing step.

(Example 3)
The surface of a straight rod-shaped body made of stainless steel with an outer diameter of 8 mm is subjected to a roughening treatment by sandblasting, and then a one-part silicone resin-based conductive adhesive (3303E, manufactured by ThreeBond Co., Ltd.) is applied to make the surface conductive. A support (core shaft) was used. Then, 50% by weight of ABS resin (Denka ABS GR-0500, manufactured by Denki Kagaku Kogyo Co., Ltd.) and 50% by weight of polyetheresteramide (IRGASTAT P18, manufactured by Ciba Specialty Chemicals Co., Ltd.) are blended to form a resin composition (volume specific) Resistance: 2 × 10 ⁸ Ωcm), and the resin composition was coated on the conductive support by injection molding to form an electric resistance adjusting layer. Next, the inner surface of the ring-shaped gap holding member made of high-density polyethylene resin (Novatech HD HY540, manufactured by Nippon Polychem), that is, the adhesive surface is subjected to a surface treatment by UV ozone irradiation, and the electric resistance of the gap holding member is adjusted. After extrapolating to both ends of the layer and bonding the gap holding member and the conductive support with a conductive adhesive, the outer diameter (maximum diameter) of the gap holding member is cut by cutting as shown in FIG. The outer diameter of the electric resistance adjusting layer was set to 12.00 mm. Subsequently, a resin composition comprising an acrylic silicone resin (3000 VH-P, manufactured by Kawakami Paint Co., Ltd.), an isocyanate curing agent, and carbon black (35% by weight based on the total solid content) is formed on the surface of the electric resistance adjusting layer. A surface layer having a film thickness of about 10 μm was formed from an object (surface resistance: 2 × 10 ⁹ Ω), and a conductive member was obtained through a firing step.

Example 4
After the surface of a straight rod-shaped body made of stainless steel having an outer diameter of 8 mm is roughened by zinc phosphate treatment, a two-component epoxy resin conductive adhesive (3380B, manufactured by ThreeBond Co., Ltd.) is applied. A conductive member was obtained in the same manner as in Example 1 except that the conductive support (core shaft) was used.

(Example 5)
After the surface of a straight rod-shaped body made of stainless steel having an outer diameter of 8 mm is roughened by zinc phosphate treatment, a one-component epoxy resin conductive adhesive (3301, manufactured by ThreeBond Co., Ltd.) is applied. A conductive support (core shaft) was used. Then, 50% by weight of ABS resin (Denka ABS GR-0500, manufactured by Denki Kagaku Kogyo Co., Ltd.) and 50% by weight of polyetheresteramide (IRGASTAT P18, manufactured by Ciba Specialty Chemicals Co., Ltd.) are blended to form a resin composition (volume specific) Resistance: 2 × 10 ⁸ Ωcm), and this resin composition was coated on the conductive support by injection molding to form an electric resistance adjusting layer. Next, the inner surface of the ring-shaped void holding member made of high-density polyethylene resin (Novatech HD HY540, manufactured by Nippon Polychem Co., Ltd.), that is, the adhesive surface is subjected to surface treatment by oxygen gas plasma irradiation, and the void holding member is electrically resisted. After extrapolating to both ends of the adjustment layer and bonding the gap holding member and the conductive support with a conductive adhesive, the outer diameter (maximum diameter) of the gap holding member is cut by cutting as shown in FIG. Was set to 12.12 mm, and the outer diameter of the electric resistance adjusting layer was set to 12.00 mm. Subsequently, a resin composition comprising an acrylic silicone resin (3000 VH-P, manufactured by Kawakami Paint Co., Ltd.), an isocyanate curing agent, and carbon black (35% by weight with respect to the total solid content) is formed on the surface of the electric resistance adjusting layer. A surface layer having a film thickness of about 10 μm was formed from an object (surface resistance: 2 × 10 ⁹ Ω), and a conductive member was obtained through a firing step.

(Comparative Example 1)
100 parts by weight of epichlorohydrin rubber (Epichromer CG, manufactured by Daiso Corporation) and 3 parts by weight of ammonium perchlorate are blended to form a rubber composition (volume resistivity: 4 × 10 ⁸ Ωcm). This rubber composition is made of stainless steel. A rubber support layer is formed by coating a conductive support (core shaft) having a diameter of 8 mm by extrusion molding, and then the rubber coating layer is subjected to a vulcanization treatment, and subsequently the rubber subjected to the vulcanization treatment. The coating layer was finished to an outer diameter of 12 mm by grinding to form an electric resistance adjusting layer. A resin composition comprising a polyvinyl butyral resin (Denka Butyral 3000-K, manufactured by Denki Kagaku Kogyo Co., Ltd.), an isocyanate curing agent, and tin oxide (60% by weight based on the total solid content) on the surface of the electric resistance adjusting layer. A surface layer having a film thickness of 10 μm was formed from an object (surface resistivity: 4 × 10 ¹⁰ Ω). Then, a tape-shaped member (DaiTac PF025-H, manufactured by Dainippon Ink Co., Ltd.) having a thickness of 50 μm is pasted around this both ends by a one-component epoxy-compound resin adhesive (2202, manufactured by ThreeBond Co., Ltd.), and after a baking process. A conductive member was obtained.

(Comparative Example 2)
ABS resin (Denka ABS GR-0500, manufactured by Denki Kagaku Kogyo Co., Ltd.) 50% by weight, and ion conductive polymer compound containing quaternary ammonium base (Rolex AS-1720, manufactured by Daiichi Kogyo Seiyaku) 50% by weight %, And the resin composition was coated on a conductive support (core shaft) made of stainless steel having an outer diameter of 8 mm by injection molding to form an electric resistance adjusting layer. Then, a ring-shaped gap holding member made of polyamide resin (Novamid 1010C2, manufactured by Mitsubishi Engineering Plastics) is inserted into both ends of the electric resistance adjusting layer, and a one-component epoxy compound resin adhesive (2202 ThreeBond) 2), the outer diameter of the gap holding member is reduced to 12.12 mm by cutting, as shown in FIG. The diameter was 12.00 mm. Subsequently, on the surface of this electric resistance adjusting layer, a resin composition (fluorocarbon (Lumiflon LF-600, manufactured by Asahi Glass Co., Ltd.), an isocyanate curing agent, and tin oxide (60% by weight based on the total solid content) ( A surface layer having a film thickness of about 10 μm was formed by a surface resistivity of 4 × 10 ¹⁰ Ω, and a conductive member was obtained through a firing process.

(Comparative Example 3)
Resin blended with 40 parts by weight of a polypropylene resin (MA2, manufactured by Nippon Polychem) and 60 parts by weight of an ion conductive polymer compound containing a quaternary ammonium base (ROLEX AS-1720, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) The resin composition was coated on a conductive support (core shaft) having an outer diameter of 8 mm by injection molding to form an electric resistance adjusting layer. A ring-shaped gap holding member made of polyamide resin (Novamid 1010C2, manufactured by Mitsubishi Engineering Plastics) is inserted into both ends of the electric resistance adjusting layer, and a synthetic rubber adhesive (1521, manufactured by ThreeBond Co., Ltd.) is inserted. ), After bonding the conductive support and the electric resistance adjusting layer, the outer diameter of the gap holding member is reduced to 12.12 mm by cutting, as shown in FIG. It was 12.00 mm. Subsequently, on the surface of this electric resistance adjusting layer, a resin composition (fluorocarbon (Lumiflon LF-600, manufactured by Asahi Glass Co., Ltd.), an isocyanate curing agent, and tin oxide (60% by weight based on the total solid content) ( A surface layer having a film thickness of about 10 μm was formed by a surface resistivity of 4 × 10 ¹⁰ Ω, and a conductive member was obtained through a firing process.

(Comparative Example 4)
A resin composition is prepared by blending 20 parts by weight of conductive carbon black (Ketjen Black EC, Ketjen Black International Co., Ltd.) with 100 parts by weight of ABS resin (Denka ABS GR-1500, manufactured by Denki Kagaku Kogyo Co., Ltd.). The object was coated on a conductive support (core shaft) made of stainless steel having an outer diameter of 8 mm by injection molding to form an electric resistance adjusting layer. Then, a ring-shaped gap holding member made of polyamide resin (Novamid 1010C2, manufactured by Mitsubishi Engineering Plastics) is inserted into both ends of the electric resistance adjusting layer, and a one-component epoxy compound resin adhesive (2202 ThreeBond) 2), the outer diameter of the gap holding member is reduced to 12.12 mm by cutting and the outer surface of the electric resistance adjusting layer is removed as shown in FIG. The diameter was 12.00 mm. Subsequently, on the surface of this electric resistance adjusting layer, a resin composition (fluorocarbon (Lumiflon LF-600, manufactured by Asahi Glass Co., Ltd.), an isocyanate curing agent, and tin oxide (60% by weight based on the total solid content) ( A surface layer having a film thickness of about 10 μm was formed by a surface resistivity: 2 × 10 ¹⁰ Ω), and a conductive member was obtained through a firing process.

  As described above, in Examples 1 to 4, in the manufacturing stage, there were no problems such as rotation of the electric resistance adjustment layer and generation of a gap between the gap holding member and the electric resistance adjustment layer in all items. In No. 4, the electric resistance adjusting layer was rotated during the outer diameter cutting process, and a positional deviation and a gap were generated between the core and the metal core. Further, rotation and detachment of the gap holding member also occurred.

(Test 1)
The conductive members obtained in Examples 1 to 4 and Comparative Examples 1 to 4 are mounted on an image forming apparatus (see FIG. 5) as a charging member, and 300,000 copies are made. The number of durable sheets until a crack occurred was examined. The voltage applied to the charging roller was DC = −800V and AC = 2400Vpp (frequency = 2 KHz). 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:
OK: No practical problem NG: Practical problem

  Looking at Table 1, we can see the following. That is, the rollers of Examples 1 to 4 did not generate cracks when copying 300000 sheets, but the rollers of Comparative Examples 1 to 4 generated cracks.

(Test 2)
The conductive member obtained in Examples 1 to 4 and Comparative Examples 1 to 4 is mounted on an image forming apparatus (see FIG. 5) as a charging member, and image evaluation is performed by copying 100,000 sheets. went. At that time, voltages applied to the charging roller were set to DC = −800 V and AC = 2400 Vpp (frequency = 2 KHz). The evaluation environment was 23 ° C. and 60% RH. The evaluation results are shown in Table 2 below.

  Table 2 shows the following. That is, in the rollers of Examples 1 to 4, good results were obtained in all items, but the rollers of Comparative Examples 1 to 4 showed defects.

(Test 3)
In the same manner as in Test 2, the image forming apparatus shown in FIG. 5 was used to evaluate the charged potential of the photoreceptor and image evaluation. At that time, voltages applied to the charging roller were set to DC = −800 V and AC = 2400 Vpp (frequency = 2 KHz). And the evaluation environment was 10 degreeC15% RH and 23 degreeC60% RH. The evaluation results are shown in the following Tables 3 and 4.

  Tables 3 and 4 show the following. That is, in the rollers of Examples 1 to 4, good results were obtained in each environment of 10 ° C. and 15% RH and 23 ° C. and 60% RH. In the high temperature and high humidity, defects on the image were observed. In particular, in the rollers of Comparative Examples 1 to 4, misalignment and gaps between the cored bar and the electric resistance adjusting layer occurred at high temperature and high humidity.

It is sectional drawing of the electroconductive member (charging roller) which shows one embodiment of this invention. It is explanatory drawing which shows the method of forming the electroconductive member (charging roller) which shows one embodiment of this invention. FIG. 3 is a schematic diagram illustrating a state where a conductive member (charging roller) is disposed on an image carrier. 1 is an explanatory diagram of an image forming apparatus according to an embodiment of the present invention. It is an explanatory view of an electrophotographic image forming apparatus having a conventional charging roller. It is sectional drawing of the conventional electroconductive member (charging roller).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Conductive support body 2 Adhesive 3 Electrical resistance adjustment layer 4 Surface layer 5 Gap holding member 6 Image carrier G Gap 10 Conductive member (charging roller)

Claims (15)

  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 the electrical resistance adjustment layer is fixed to the conductive support with an adhesive.   The conductive member according to claim 1, wherein the adhesive is a conductive adhesive.   The conductive member according to claim 2, wherein the conductive adhesive contains conductive particles selected from gold, silver, nickel, and carbon.   The conductive member according to claim 1, wherein the adhesive is previously applied to a conductive support.   The conductive member according to claim 1, wherein a surface of the conductive support is roughened.   The conductive member according to claim 1, wherein the conductive support and the gap holding member are fixed with the adhesive.   The conductive member according to claim 6, wherein an adhesive surface of the gap holding member is surface-treated with an active gas in advance.   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. 9. The conductive member according to claim 8, 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 electric resistance adjusting layer.   The conductive member according to claim 1, wherein a surface layer that prevents adhesion of toner is formed on the electric resistance adjusting layer.   11. The resin constituting the surface layer is a resin selected from an acrylic silicon resin, a fluororesin, a silicone resin, an acrylic resin, a polyamide resin, a polyurethane resin, a polyester resin, and a polyvinyl butyral resin. The electroconductive member as described in.   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.   14. A process cartridge, wherein the charging member according to claim 13 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 14.

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