JP2011128448A - Conductive member, charging device, process cartridge, and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a conductive member configured so that contaminant such as a discharge product adhering to a surface of a surface layer in the conductive member is easily removed by cleaning, to prevent an abnormal image from being formed by the contaminant, and having excellent durability. <P>SOLUTION: The conductive member 101 includes a conductive support body 1, an electrical resistance adjustment layer 2 disposed on the conductive support body 1 and the surface layer 3 disposed on the electrical resistance adjustment layer 2, wherein [1] the surface layer 3 is composed of a crosslinking reaction product of resin composition containing at least (a) polyether polyol resin, (b) polyol resin grafted with silicon, (c) organic anion containing fluorine that contains alkali metal or alkali earth metal, and (d) polyisocyanate, and [2] the polyether polyol resin is composed of short-chain polyether polyol resin having 400 to 1,000 average molecular weight and long-chain polyether polyol resin having 2,000 to 3,000 average molecular weight. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

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

  In electrophotographic image forming apparatuses such as conventional electrophotographic copying machines, laser printers, and facsimile machines, a conductive member is generally used as a charging member that performs a charging process on an image carrier (photosensitive member). It has been. FIG. 6 is a schematic explanatory diagram of a conventional electrophotographic image forming apparatus.

  In FIG. 6, reference numeral 400 denotes a conventional electrophotographic image forming apparatus. A conventional electrophotographic image forming apparatus 400 includes an image carrier 311 on which an electrostatic latent image is formed, a charging roller 312 that performs charging processing in contact with the image carrier 311, an exposure unit 313 such as a laser beam, an image, and the like. The developing roller 314 for attaching toner to the electrostatic latent image on the carrier 311, the transfer roller 316 for transferring the toner image on the image carrier 311 to the recording paper 317, and the image carrier 311 after the transfer processing are cleaned. A cleaning device 318 for the purpose. In FIG. 6, functional units normally required in other electrophotographic processes are omitted because they are not required in this specification.

  Next, a basic image forming operation in charging of the conventional electrophotographic image forming apparatus 400 will be described.

  When a DC voltage is supplied from a power pack (not shown) to the charging roller 312 in contact with the image carrier 311, the surface of the image carrier 311 is uniformly charged at a high potential. Immediately after that, when the image light is irradiated from the exposure means 313 to the surface of the image carrier 311, the potential of the portion of the image carrier 311 irradiated with the image light is lowered. It is known that such a charging mechanism to the surface of the image carrier 311 by the charging roller 312 is a discharge according to Paschen's law in a minute space between the charging roller 312 and the image carrier 311.

  Since the image light has a light amount distribution corresponding to white / black of the image, when the image light is irradiated onto the surface of the image carrier 311, the potential distribution corresponding to the recorded image on the surface of the image carrier 311, that is, An electrostatic latent image is formed. When the portion of the image carrier 311 on which the electrostatic latent image is formed in this way passes through the developing roller 314, 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 317 is conveyed to a portion of the image carrier 311 where 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 onto the recording paper by the transfer roller 316, the recording paper 317 is separated from the image carrier 311. The separated recording paper 317 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 311 is cleaned by the cleaning device 318. Further, residual charges are removed by a quenching lamp (not shown), and the next image forming process is performed. Prepared for.

As a charging method using a charging roller, a contact charging method in which a roller is brought into contact with an image carrier is generally used.
(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 technique using a proximity charging method (see Patent Documents 1 to 3) in which a conductive member (charging roller) is brought close to an image carrier has been proposed. In this proximity charging technique, 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). This is due to the charging method. In this proximity charging technique, since the charging roller and the image carrier are not in contact, there has been a problem in the conventional contact charging technique. (A) The substance constituting the charging roller is an image carrier. The problems of adhering to the body and (b) permanent deformation when the image carrier is stopped for a long time are eliminated. In this proximity charging technique, the amount of toner adhering to the charging roller is reduced, so that the toner on the image carrier is less likely to adhere to the charging roller, and therefore the charging performance of the charging roller does not deteriorate. .

  In addition, a gap holding member is press-fitted into both ends of an electric resistance adjusting layer of a conductive member (charging roller) that has been used in the proximity charging method charging device, and then the electric resistance adjusting layer and the gap holding member are There has been proposed a technique (see Patent Document 4) in which a simultaneous removal process is performed to form a charging roller. With this technique, a minute gap between the electric resistance adjusting layer and the image carrier can be precisely controlled.

  However, in the conductive member (charging roller) using the proximity charging unit method, resistance unevenness due to gap fluctuation is likely to occur. Therefore, in order to prevent this charging unevenness, a voltage obtained by superimposing a high-voltage AC voltage on the DC voltage is applied. is doing. Further, in the conductive member (charging roller) using the proximity charging unit method, if the shape of the electric resistance adjusting layer changes, a minute gap between the electric resistance adjusting layer and the image carrier becomes non-uniform. There have been problems that the surface of the roller is soiled, the surface of the image carrier is contaminated, and the surface of the charging roller is unevenly charged.

  By the way, in the charging device using the proximity charging unit method, contaminants such as discharge products are generated between the image carrier and the charging member (charging roller) due to the superimposed AC voltage. Is accumulated on the surface of the charging member (charging roller), and therefore, it is preferable to make the minute gap between the electric resistance adjusting layer and the image carrier as large as possible. The larger the charging margin for the minute gap between the electric resistance adjusting layer and the image carrier, the better. Current conductive materials for charging members include conductive carbon such as kettin black EC and acetylene black, conductive polymers such as polyaniline, polypyrrole and polyacetylene, ionic conductive substances, and sodium perchlorate and perchloric acid. There are inorganic ionic conductive materials such as lithium, calcium perchlorate, and lithium chloride. The latter ion conductive system is advantageous for abnormal discharge such as spot images and leakage resistance because it can be dispersed (dissolved) at the molecular level.

  Therefore, in order to solve the above-mentioned problem, a conductive material having an ion conductive surface layer composed of a resin obtained by condensing an ionic conductive agent containing an alkali metal or an alkaline earth metal and a polyether polyol with a curing agent. A characteristic member (charging roller) (see Patent Document 4) has been proposed. According to this conductive member, the metal ions of the ionic conductive agent are coordinated to the oxygen atoms of the polyether as the matrix polymer, so that the ions easily move (that is, the electricity easily flows). The roller dirtiness will be improved.

  The present inventors also have a conductive support, a conductive resistance adjustment layer provided on the conductive support, and a surface layer provided on the electrical resistance adjustment layer. In the member (charging roller), the surface layer includes at least (a) a polyol resin grafted with fluorine or silicon, (b) a polyether polyol resin, (c) a fluorine-containing organic material containing an alkali metal or an alkaline earth metal. An anionic salt and (d) polyisocyanate, which is an ionic conductive system that is made up of a material system that can reduce resistance, so that abnormal discharge occurs even if a wide gap is provided between the image carrier and the charging member. By making it difficult to do so, a technology (Japanese Patent Application No. 2008-119038, unpublished) has been proposed in which a roller member is further improved in dirt resistance.

  However, in the above technique, the adhesiveness of the surface layer having ionic conductivity is increased and the surface layer becomes soft, so that contaminants such as discharge products are easily attached to the surface layer. Contaminants such as discharge products sandwiched in the minute gap between the carrier and the conductive member cannot be removed by the cleaning member by sticking to the surface layer, and thus the minute gap between the image carrier and the conductive member. There is a problem that an abnormal image is generated due to contaminants such as discharge products sandwiched between the two.

  In addition, a technique (see Patent Document 5) has been proposed in which a solid lubricant powder is applied to the surface of a conductive member to form a charging member in which the adhesiveness of the surface of the conductive member is reduced. Although this technology has reduced the occurrence of abnormal images such as color spot images due to contaminants such as discharge products sandwiched in a minute gap between the image carrier and the conductive member, it is not sufficient. There wasn't.

  The present invention aims to solve this problem.

  That is, the present invention provides a contaminant such as a discharge product adhered to the surface of the surface layer of the conductive member without damaging the surface of the surface layer of the conductive member while maintaining the chargeability of the conductive member. It is an object of the present invention to provide a conductive member, a charging device, a process cartridge, and an image forming apparatus with excellent durability, which can be easily removed by cleaning and prevent occurrence of abnormal images due to the contaminants.

In order to achieve the above object, the invention described in claim 1 is formed on a conductive support, an electrical resistance adjustment layer provided on the conductive support, and the electrical resistance adjustment layer. In the conductive member having a surface layer,
(A) The surface layer is a) a polyether polyol resin, b) a polyol resin grafted with silicon, c) a fluorine-containing organic anion containing an alkali metal or an alkaline earth metal, and d) poly Composed of a crosslinking reaction product of a resin composition containing isocyanate, and
(B) The polyether polyol resin is composed of a short-chain polyether polyol resin having an average molecular weight of 400 to 1000 and a long-chain polyether polyol resin having an average molecular weight of 2000 to 3000. It is a member.

  The invention described in claim 2 is the invention described in claim 1, wherein the long-chain polyether polyol resin has the same content ratio as the short-chain polyether polyol resin or the short-chain polyether polyol. It is contained at a content ratio higher than the resin content ratio.

  The invention described in claim 3 is the invention described in claim 1 or 2, wherein the polyether polyol resin is contained in a ratio of 35 to 55% by weight with respect to the total resin constituting the surface layer. It is characterized by being.

  The invention described in claim 4 is the invention described in any one of claims 1 to 3, wherein the polyether polyol resin has a polyether content in terms of ethylene oxide of 40 to 80% by weight. It is characterized by being.

  The invention described in claim 5 is the invention described in any one of claims 1 to 4, wherein a certain minute gap is formed at both ends of the conductive member by contacting the image carrier. A ring-shaped gap holding member is provided.

  A sixth aspect of the present invention is a charging device comprising the conductive member according to any one of the first to fifth aspects as a charging member.

  According to a seventh aspect of the present invention, in the process cartridge in which the image carrier and the charging device are integrally supported and are detachably fixed to the main body of the image forming apparatus, the charging device is the sixth aspect. A process cartridge comprising the charging device described above.

  According to an eighth aspect of the present invention, a process cartridge, exposure means for exposing the surface of the image carrier to form an electrostatic latent image, and supplying toner to the electrostatic latent image on the surface of the image carrier. 7. An image forming apparatus comprising at least a developing unit that visualizes and a transfer unit that transfers a visualized image of the surface of the image carrier onto a transfer medium, wherein the process cartridge includes the process cartridge according to claim 6. The image forming apparatus is characterized by the above.

  According to the invention described in claim 1, a conductive support, an electrical resistance adjustment layer provided on the conductive support, a surface layer formed on the electrical resistance adjustment layer, (A) the surface layer is a) a polyether polyol resin, b) a polyol resin grafted with silicon, c) a fluorine-containing organic anion containing an alkali metal or an alkaline earth metal And (d) a crosslinking reaction product of a resin composition containing a polyisocyanate, and (b) the polyether polyol resin has an average molecular weight of 400 to 1000 and a short-chain polyether polyol resin. The surface layer is hardened, and therefore the chargeability of the conductive member is maintained. However, the contaminants such as discharge products attached to the surface of the surface layer of the conductive member can be easily removed by cleaning without damaging the surface of the surface layer of the conductive member. Thus, it is possible to provide a conductive member that is excellent in durability and that prevents the occurrence of.

  According to the invention described in claim 2, the long-chain polyether polyol resin has a content ratio equal to that of the short-chain polyether polyol resin, or a content ratio greater than the content ratio of the short-chain polyether polyol resin. Therefore, the surface layer is further hardened while maintaining a low resistance, and therefore, more durable and conductive that enables stable charging of the image carrier under any environment. A member can be provided.

  According to the invention described in claim 3, since the polyether polyol resin is contained in a ratio of 35 to 55% by weight with respect to the total resin constituting the surface layer, the surface layer is low. Thus, it is possible to provide a conductive member that is further hardened while maintaining the resistance, and that is capable of stably charging the image carrier under any environment, and that is more durable.

  According to the invention described in claim 4, since the polyether content in terms of ethylene oxide in the polyether polyol resin is 40 to 80% by weight, the electrical resistance of the conductive member (charging member) is reduced. Therefore, it is possible to provide a conductive member that is unlikely to be abnormally discharged even if a very small gap is provided between the image carrier and the conductive member (charging member).

  According to the fifth aspect of the present invention, since the ring-shaped gap holding members that contact the image carrier and form a certain minute gap are provided at both ends of the conductive member, Residual substances such as toner remaining on the surface of the body are more difficult to adhere to the conductive member.

  According to the invention described in claim 6, since the charging device includes the conductive member according to any one of claims 1 to 5 as a charging member, the conductive member (charging member) A low electrical resistance can be achieved, and for this reason, it is possible to provide a charging device that is unlikely to abnormally discharge even if a very small gap is provided between the image carrier and the conductive member (charging member).

  According to the seventh aspect of the present invention, in the process cartridge in which the image carrier and the charging device are integrally supported and are detachably fixed to the main body of the image forming apparatus, the charging device is the sixth aspect. Therefore, it is possible to obtain a stable image quality over a long period of time, and the user can be replaced and simplified.

  According to the invention described in claim 8, the process cartridge, the exposure means for exposing the surface of the image carrier to form an electrostatic latent image, and the toner on the electrostatic latent image on the surface of the image carrier. The process cartridge according to claim 7, wherein the process cartridge is a process cartridge according to claim 7, comprising: a developing unit that supplies and visualizes; and a transfer unit that transfers a visualized image of the surface of the image carrier onto a transfer medium. Since it is configured, a high image quality can be obtained and a stable image can be obtained over a long period of time.

FIG. 3 is a schematic view showing a state where a conductive member (charging roller) showing an embodiment of the present invention is arranged on an image carrier. It is the sectional view on the AA line in FIG. It is a schematic explanatory drawing of the process cartridge which has the electroconductive member (charging roller) which shows one embodiment of invention. 1 is a schematic explanatory diagram of an image forming apparatus (image MP MP6000 manufactured by Ricoh) having a process cartridge according to an embodiment of the present invention. FIG. 5 is an enlarged explanatory view of an image forming unit in the image forming apparatus shown in FIG. 4. It is a schematic explanatory diagram of a conventional electrophotographic image forming apparatus.

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

  In the conductive member having a conductive support, an electric resistance adjusting layer provided on the conductive support, and a surface layer formed on the electric resistance adjusting layer. (A) The surface layer is a) a polyether polyol resin, b) a polyol resin grafted with silicon, c) a fluorine-containing organic anion containing an alkali metal or an alkaline earth metal, and d) (B) the polyether polyol resin is composed of a short-chain polyether polyol resin having an average molecular weight of 400 to 1000 and a long chain having an average molecular weight of 2000 to 3000. The long-chain polyether polyol resin is cross-linked with polyisocyanate. As the base resin skeleton is formed, the short-chain polyether polyol resin is inserted into the gap of the resin skeleton, the filling density of the polyether polyol resin as a whole is increased. While maintaining the chargeability of the conductive member, the surface of the surface layer of the conductive member is not damaged, and contaminants such as discharge products attached to the surface of the surface of the conductive member can be easily removed by cleaning. Thus, the present invention has been completed by finding that it is possible to provide a conductive member having excellent durability and preventing the occurrence of abnormal images due to the contaminants.

  That is, as shown in FIGS. 1 and 2, the conductive member (charging roller) 101 of the present invention includes a conductive support 1 and an electric resistance adjusting layer provided on the conductive support 1. 2 and a surface layer 3 formed on the electric resistance adjusting layer 2. In the electrical resistance adjusting layer 4, (a) the surface layer 3 is made of a) a polyether polyol resin, b) a polyol resin grafted with silicon, c) an alkali metal or an alkaline earth metal. And (b) the polyether polyol resin is a short-chain polyether having an average molecular weight of 400 to 1000, and d) a cross-linking reaction product of a resin composition containing polyisocyanate. It consists of a polyol resin and a long-chain polyether polyol resin having an average molecular weight of 2000 to 3000. In FIG. 1, 4 is a gap holding member, 5 is a bearing, and 6 is a pressure spring (pressure member).

  As described above, the conductive support 1, the electrical resistance adjustment layer 2 provided on the conductive support 1, and the surface layer 3 formed on the electrical resistance adjustment layer 2. In the conductive member 101, (a) the surface layer 3 is a) a polyether polyol resin, b) a polyol resin grafted with silicon, c) a fluorine-containing organic anion containing an alkali metal or an alkaline earth metal. And (d) composed of a crosslinking reaction product of a resin composition containing a polyisocyanate, and (b) the polyether polyol resin is a short-chain polyether polyol resin having an average molecular weight of 400 to 1000, and an average molecular weight. 2000-3000 long-chain polyether polyol resin, the long-chain polyether polyol resin is a polyisocyanate. As a result, the base resin skeleton is crosslinked and the short-chain polyether polyol resin is inserted into the gaps of the resin skeleton, so that the packing density of the polyether polyol resin is increased as a whole. In addition, while maintaining the chargeability of the conductive member, the surface of the surface layer of the conductive member is not damaged, and contaminants such as discharge products adhering to the surface of the surface layer 3 of the conductive member 101 are cleaned. It is possible to provide the conductive member 101 having excellent durability that is easily removed and prevents the occurrence of abnormal images due to the contaminants.

  In the present invention, the long-chain polyether polyol resin is preferably contained in a content ratio equal to that of the short-chain polyether polyol resin or a content ratio greater than the content ratio of the short-chain polyether polyol resin. Yes. Thus, when the long-chain polyether polyol resin is contained in a content ratio equal to that of the short-chain polyether polyol resin or a content ratio greater than the content ratio of the short-chain polyether polyol resin, To provide a conductive member 101 having a higher durability that allows the surface layer 3 to be further hardened while maintaining a low resistance, thereby enabling stable charging of the image carrier 61 in any environment. Can do.

  In the present invention, the polyether polyol resin is preferably contained in a ratio of 35 to 55% by weight with respect to the total resin constituting the surface layer 3. Thus, when the polyether polyol resin is contained at a ratio of 35 to 55% by weight with respect to the total resin constituting the surface layer 3, the surface layer 3 further maintains a low resistance. Therefore, it is possible to provide the conductive member 101 having higher durability that enables the image carrier 61 to be stably charged in any environment.

  In the present invention, the content of the polyether in terms of ethylene oxide in the polyether polyol resin is preferably 40 to 80% by weight. Thus, when the content of the polyether in terms of ethylene oxide in the polyether polyol resin is 40 to 80% by weight, the surface layer 3 is further hardened while maintaining low resistance. It is possible to provide the conductive member 101 having further excellent durability that enables stable charging of the image carrier 61 below.

  As shown in FIG. 1, a ring-shaped gap holding member 4 that forms a fixed minute gap G in contact with an image carrier 61 at both ends of the conductive member (charging roller) 101 of the present invention. Is provided. As described above, when the ring-shaped gap holding members 4 that are in contact with the image carrier 61 and form a certain minute gap G are provided at both ends of the conductive member 101, the surface of the image carrier 61 is provided. Residual substances such as toner remaining on the conductive member 101 become more difficult to adhere to the conductive member 101.

What is necessary for the gap holding unit 4 is to form the minute gap G with the image carrier (photosensitive member) 61 stably over the environment and for a long time (time). Preferably, it is made of a resin material having low hygroscopicity and wear resistance. Further, with respect to the resin material constituting the gap holding portion 104, it is difficult for toner and toner additive to adhere thereto, and the image carrier (photosensitive member) 61 is not worn because it slides in contact with the photosensitive member. Therefore, the resin material constituting the gap holding portion 104 is appropriately selected according to various conditions. Specific examples of the resin material constituting the gap holding unit 104 include polyethylene (PE), polypropylene (PP), polyacetal (POM), polymethyl methacrylate (PMMA), polystyrene (PS), and copolymers thereof. General purpose resins such as (AS, ABS), polycarbonate (PC), urethane, fluorine (PTFE) and the like can be mentioned. The gap holding member 4 is preferably an insulating material and preferably has a volume resistivity of 10 ⁻¹³ Ωcm or more. The reason why the insulating material is necessary is to eliminate generation of a leakage current with the photoconductor. As a method for forming the minute gap G, the gap holding member 4 formed by molding is installed at both ends of the electric resistance adjusting layer 2 or a solvent-soluble resin material is applied. It is also possible. It is also possible to increase the accuracy of the gap holding portion 4 by removing processing such as cutting and grinding. Further, by processing the gap holding member 4 and the electric resistance adjusting layer 2 at the same time, the minute gap G may be made more accurate.

  Next, the conductive member 101 will be described in more detail.

<About electrical resistance adjustment layer>
The electric resistance adjusting layer 2 is formed of a thermoplastic resin composition in which a polymer ion conductive material is dispersed. The volume resistivity of the electrical resistance adjusting layer 2 is preferably 10 ⁻⁶ to 10 ⁻⁹ Ωcm. When the volume resistivity of the electric resistance adjusting layer 2 exceeds 10 ⁻⁹ Ωcm, charging ability and transfer capability are insufficient, and the volume resistivity of the electric resistance adjusting layer 2 is lower than 10 ^{−6 6} Ωcm. Then, leakage due to voltage concentration on the entire image carrier (photosensitive member) 61 occurs. The thermoplastic resin used for the electrical resistance adjusting layer 2 is not particularly limited, but preferably polyethylene (PE), polypropylene (PP), polymethyl methacrylate (PMMA), polystyrene (PS) and The resin (AS, ABS), polyamide, polycarbonate (PC) and the like are easily molded.

  The polymer ion conductive material dispersed in the thermoplastic resin is preferably a polymer compound containing a polyether ester amide component. Since the polyether ester amide is an ion conductive polymer material, it is uniformly dispersed and fixed at a molecular level in a matrix polymer. For this purpose, an electron conductive conductive agent such as a metal oxide or carbon black is used. There is no variation in resistance value due to poor dispersion as seen in a dispersed composition. In addition, when a high applied voltage is applied as a conductive member, in the case of an electron conductive conductive agent, a path through which electricity easily flows locally is formed, so that a leakage current to the image carrier is generated. When the conductive member is used as a charging member, a white / black spot image that is an abnormal image is generated. Since polyether ester amide is a polymer material, bleeding out hardly occurs. Since the electrical resistance value of the conductive member needs to be a desired value, the blending amount of the thermoplastic resin and the polymer type ionic conductive agent is preferably 20 to 70% by weight of the thermoplastic resin and the polymer. Type ion conductive agent is 80 to 20% by weight.

  In the present invention, an electrolyte (salt) can be added to adjust the electric resistance value of the conductive member 101. Examples of the salt include alkali metal salts such as sodium perchlorate and lithium perchlorate, and quaternary phosphonium salts such as ethyltriphenylphosphonium tetrafluoroborate and tetraphenylphosphonium bromide. The conductive agent may be used singly or as a blend of two or more as long as the physical properties are not impaired.

  When a compatibilizer is added to the matrix polymer, the conductive material can be micro-dispersed. Therefore, in order to uniformly disperse the conductive material in the matrix polymer at a molecular level, the compatibilizer is added to the matrix polymer. You may use it. In addition, an additive such as an antioxidant may be used in the matrix polymer as long as the physical properties are not impaired.

  There is no restriction | limiting in particular about the manufacturing method of the resin composition which comprises the said electrical resistance adjustment layer 2, It can manufacture easily by mixing each material and melt-kneading with a biaxial kneader, a kneader, etc. The electric resistance adjusting layer 2 can be easily formed on the conductive support 1 by covering the conductive support 1 with the conductive resin composition by means such as extrusion molding or injection molding. Can do. When only the electric resistance adjusting layer 2 is formed on the conductive support 1 to form the conductive member 101, toner, toner additives, etc. adhere to the electric resistance adjusting layer 2 and the performance deteriorates. There is. Such a problem can be prevented by forming the surface layer 3 on the electric resistance adjusting layer 2.

<About surface layer>
The surface layer is preferably made of a non-adhesive resin such as a fluorine resin, a silicone resin, a polyamide resin, or a polyester resin. As described above, when the surface layer is made of the non-adhesive resin, it is possible to prevent toner from sticking.

  When the material constituting the surface layer 3 is made into a two-component paint using a curing agent in combination and applied to the surface of the electric resistance adjusting layer 2, the environmental resistance, non-adhesiveness, and releasability of the surface layer 3 are obtained. Can be increased. The two-component paint is preferably composed of a resin having a hydroxyl group in the molecule and an isocyanate resin that causes a crosslinking reaction with the hydroxyl group. The isocyanate-based resin can cause a crosslinking and curing reaction at a relatively low temperature of 100 ° C. or less. In the two-component paint, the crosslinking density of the surface layer 3 can be set relatively freely by changing the blending amount of the curing agent with respect to 1 equivalent of the functional group (OH group) in the resin having a hydroxyl group in the molecule. Can be changed and adjusted. The resin constituting the surface layer 3 is preferably a silicone resin or a resin grafted with silicon or fluorine in consideration of non-adhesiveness to the toner.

  Since electrical characteristics (electrical resistance value) are important for the conductive member 101, the surface layer 3 needs to be conductive. In order to make the surface layer 3 conductive, a conductivity imparting material (electrolyte salt) may be dispersed in the resin material forming the surface layer 3. Examples of the conductivity-imparting material (electrolyte salt) include alkali metal perchlorates such as sodium perchlorate, lithium perchlorate, calcium perchlorate, and lithium chloride, alkaline earth metal salts, lithium bis (trifluoro) Fluorinated organic anionic salts such as quaternary phosphonium salts such as (romethanesulfonyl) imide, lithium tris (trifluoromethanesulfonyl) methane, lithium trifluoromethanesulfonate, titriphenylphosphonium / tetrafluoroborate, tetraphenylphosphonium / bromide, modified fatty acids Examples thereof include dimethylammonium ethosulphate, ammonium stearate acetate, and laurylammonium acetate. Among them, lithium bis (trifluoromethanesulfonyl) imide, lithium tris (trifluoromethanesulfonyl) methane, and lithium trifluoromethanesulfonate can reduce electric resistance.

  In order to reduce the electrical resistance by ionic conduction, polyether polyols (ether oxygen) made of polyethylene oxide, polypropylene oxide, copolymers thereof, or the like are required. These polyether polyol resins are preferably 20 to 70% by weight, more preferably 35 to 55% by weight, based on the total resin forming the surface layer (coating film) 3. Moreover, content of the polyether in conversion of ethylene oxide in the said polyether polyol resin is 40 to 80 weight%. Thus, when the content of the polyether in terms of ethylene oxide in the polyether polyol resin is 40 to 80% by weight, the electrical resistance of the conductive member (charging member) 101 can be reduced, and therefore In addition, it is possible to provide a conductive member that is unlikely to cause abnormal discharge even if a very small gap is provided between the image carrier 61 and the conductive member (charging member) 101. Moreover, the polyether oxygen amount (ethylene oxide equivalent amount; EO amount) in the polyether polyol is preferably 40 wt. In addition, the polyether oxygen amount (the product of the polyether polyol resin ratio and the EO amount) in the polyether polyol in the entire surface layer 3 is preferably 25% by weight or more, and more preferably 45% by weight. Degree. In addition, the electrolyte salt is used singly or by blending a plurality of electrolyte salts as long as the physical properties of the surface layer 3 are not impaired.

  In the present invention, the polyether resin in the surface layer 3 is composed of a short-chain polyether polyol resin and a polyether resin having a long chain with respect to the short-chain polyether resin. Thus, when the polyether resin in the surface layer 3 is composed of a short-chain polyether polyol resin and a polyether resin that is a long chain with respect to the short-chain polyether resin, The surface layer 3 is increased in hardness in addition to being reduced in electrical resistance. The short-chain polyether polyol resin preferably has an average molecular weight of 1,000 or less, and the polyether polyol resin having a long chain with respect to the short-chain polyether polyol resin preferably has an average molecular weight of 2000 to 2000. 3000. The number of functional groups in the polyether resin is preferably 2 or 3, that is, diol or triol.

  The reason for the average molecular weight of the short-chain polyether resin being an average molecular weight of 1,000 or less is that the average molecular weight of the short-chain polyether resin is smaller and the degree of freedom is higher, and enters the long-chain polyether resin polymer gap. It is easy. Further, if the average molecular weight of the short-chain polyether resin is larger than 1,000, the surface layer 3 becomes flexible, which is not preferable.

  The reason why the polyether polyol resin having a long chain with respect to the short-chain polyether resin preferably has an average molecular weight of 2000 to 3000 is that when the average molecular weight of the polyether polyol resin having a long chain is smaller than 2000, the short-chain polyether resin This is because the polyether polyol resin cannot be contained, and the effect of increasing the target packing density and the improvement of the crosslinking density cannot be expected. In addition, if the polyether polyol resin that becomes the long chain is larger than 3000, the polyether polyol resin is softened. Therefore, even if the target structure is obtained as the surface layer 3, the surface layer 3 This is not preferable because a high hardness cannot be obtained.

  The long-chain polyether polyol resin is cross-linked with polyisocyanate to form a base skeleton, and the short-chain polyether polyol resin enters the polymer gap of the long-chain polyether resin to increase the packing density. The bridge density by the polyisocyanate of the long-chain polyether resin and the short-chain polyether polyol resin is increased by increasing the polyisocyanate and performing a crosslinking reaction to act as a binder. Therefore, the surface layer 3 becomes hard. The ratio of the short-chain polyether polyol resin and the long-chain polyether polyol resin may be the same as the ratio of the long-chain polyether polyol resin in terms of% by weight, but about 1: 1. preferable.

  The resin material constituting the surface layer 3 is dissolved in an organic solvent to prepare a paint, and this is coated on the surface of the electric resistance adjusting layer 2 by a coating means such as spray coating, dipping, roll coating, etc. To form the surface layer 3.

  As shown in FIG. 1, the charging device 100 of the present invention includes the conductive member 101 according to any one of claims 1 to 5 as a charging member. As described above, when the conductive member 101 according to any one of claims 1 to 5 is included as a charging member, the electrical resistance of the conductive member (charging member) 101 can be reduced. Therefore, it is possible to provide the charging device 100 that is unlikely to cause abnormal discharge even if the minute gap G between the image carrier 61 and the conductive member (charging member) 101 is wide.

  Next, the charging device 100 will be described in more detail.

  As shown in FIGS. 1 and 3, the charging device 100 includes a conductive member (charging member) 101 provided with a minute gap G facing the image carrier 61 and the conductive material. At least a cleaning member 102 that cleans the member 101, a power source (not shown) that applies a voltage to the charging member 101, and a pressure spring 6 that pressurizes and contacts the charging member 101 to the image carrier 61. ing. Further, the conductive member 101 is disposed opposite to the image carrier 61 with a minute gap G therebetween. The minute gap G between the conductive member 101 and the image carrier 61 is formed by bringing the gap holding member 4 into contact with the non-image forming area of the conductive member 101. By bringing the gap holding member 4 into contact with the photosensitive layer region of the image carrier 61, even if the coating thickness of the photosensitive layer on the image carrier 61 varies, it is possible to prevent variations in the minute gap G.

  The shape of the conductive member (charging member) 101 is a curved surface that gradually separates from the closest part to the image carrier 61 in the moving direction of the image carrier 61. As described above, when the shape of the conductive member (charging member) 101 is formed as a curved surface that gradually separates from the closest part to the image carrier 61 in the moving direction of the image carrier 61, The image carrier 61 can be more uniformly charged. Therefore, when the conductive member (charging member) 101 has a cylindrical shape, the image carrier 61 can be charged uniformly. Further, the discharging surface of the conductive member (charging member) 101 is subjected to strong stress. Since the discharge always occurs on the same surface of the conductive member 101, the deterioration thereof is promoted and may be scraped off. Therefore, if the entire surface of the conductive member 101 can be used as a discharge surface, it can be used over a long period of time by rotating it to prevent early deterioration.

  The minute gap G between the conductive member 101 and the image carrier 61 is preferably set to 100 μm or less, more preferably 5 to 70 μm, by the gap holding member 4. Thereby, it is possible to suppress the formation of an abnormal image when the charging device 100 is operated in a room temperature and humidity environment. When the minute gap G is 100 μm or more, the distance to reach the image carrier 61 becomes long, so that the discharge start voltage according to Paschen's law becomes large, and the discharge space to the image carrier 61 becomes large. In order to charge the image carrier 61 to a predetermined charge, a large amount of discharge products are required due to the discharge. Therefore, a large amount of the discharge products remain in the discharge space after image formation and adhere to the image carrier 61. As a result, the deterioration of the image carrier 61 with time is promoted. Further, when the minute gap G is small, the reach distance to the image carrier 61 is shortened, so that the image carrier 61 can be charged even if the discharge energy is small. However, since the space formed by the conductive member 101 and the image carrier 61 becomes narrow, the air flow becomes worse. For this reason, the discharge product formed in the discharge space stays in this space and remains in the discharge space in a large amount after the image formation, as in the case where the minute gap G is large. It adheres and causes deterioration of the image carrier 61 over time. Therefore, it is preferable to reduce the discharge energy to reduce the generation of discharge products and to form a space that does not retain air. Therefore, the minute gap G is preferably 100 μm or less, and more preferably 5 to 70 μm.

  As shown in FIG. 3, in the process cartridge 200 of the present invention, the image carrier 61 and the charging device 100 are integrally supported, and are detachably fixed to the main body (not shown) of the image forming apparatus. Has been. The charging device 100 includes the charging device 100 according to claim 6. In this manner, in the process cartridge 200 in which the image carrier 61 and the charging device 100 are integrally supported and are detachably fixed to the main body of the image forming apparatus, the charging device 100 is the charging according to claim 6. When the apparatus 100 is configured, stable image quality can be obtained over a long period of time, and replacement can be simplified by user maintenance.

  Next, the process cartridge 200 will be described in more detail.

  The process cartridge 200 includes at least the image carrier 61, the charging device 100, and the cleaning device 64, but may include a developing device 63. The process cartridge 200 is an integral unit and can be freely attached to and detached from the image forming apparatus.

  The charging device 100 in the process cartridge 200 has a power source (not shown) that applies a voltage to the conductive member (charging member) 101. The voltage applied by the power source may be only a DC voltage, but a voltage obtained by superimposing a DC voltage and an AC voltage is preferable. If there is a non-uniform portion in the layer structure of the charging member 101, the surface potential of the image carrier 61 may become non-uniform when only a DC voltage is applied. With the superposed voltage, the charging member 101 has an equipotential surface, so that the discharge is stable and the image carrier 61 can be charged uniformly. With the alternating voltage at the superimposed voltage, the peak-to-peak voltage is preferably at least twice the charging start voltage of the image carrier 61. The charging start voltage is an absolute value of a voltage when the image carrier 61 starts to be charged when only a direct current is applied to the charging member 101. Since this charging start voltage causes reverse discharge from the image carrier 61 to the charging member 101, the leveling effect makes it possible to uniformly charge the image carrier 61 in a more stable state. The frequency of the AC voltage is preferably 7 times or more the peripheral speed (process speed) of the image carrier 61. By setting the frequency to 7 times or more the peripheral speed of the image carrier 61, the moire image cannot be recognized (visually).

  In the cleaning device 64 in the process cartridge 200, a solid lubricant formed into a block shape with zinc stearate by the application roller 64b by applying pressure to the brush roller 64d, which is an application member, by a pressure member such as a spring. The solid lubricant scraped off from the block 64a is applied to the image carrier 61. In the cleaning device 64, a cleaning member (urethane blade) 64c made of urethane is provided in a counter manner. Further, since the cleaning member 102 of the charging member 101 is provided in a system that rotates together with the charging member 101 by using a melamine resin sponge roller, the surface of the charging member 101 is favorably stained. Can be cleaned.

  As shown in FIGS. 3 to 5, the image forming apparatus 300 according to the present invention exposes a process cartridge 200 and an exposure unit (exposure apparatus) 70 that forms an electrostatic latent image by exposing the surface of the image carrier 61. And a developing means (developing device) 63 for supplying toner to the electrostatic latent image on the surface of the image carrier 61 for visualization, and a transfer means (for transferring the visualized image on the surface of the image carrier 61 to a transfer medium). Intermediate transfer member) 50. The process cartridge 200 includes the process cartridge 200 according to claim 7. Thus, the toner is applied to the process cartridge 200, the exposure means (exposure device) 70 for exposing the surface of the image carrier 61 to form an electrostatic latent image, and the electrostatic latent image on the surface of the image carrier 61. In an image forming apparatus 300 provided with at least developing means (developing apparatus) 63 for supplying and visualizing, and transfer means (intermediate transfer body) 50 for transferring a visualized image of the surface of the image carrier 61 to a transfer medium, When the process cartridge 200 includes the process cartridge 200 according to the seventh aspect, high image quality can be obtained and a stable image can be obtained over a long period of time.

  Next, the image forming apparatus 300 will be described in more detail.

  The image forming apparatus 300 is a drum having a photosensitive layer on the surface, and images corresponding to four colors of yellow (Y), magenta (M), cyan (C), and black (K). A carrier 61, a charging device 100 that charges each image carrier 61 almost uniformly, an exposure device 70 that forms an electrostatic latent image by exposing the charged image carrier 61 with laser light, yellow, A developing device 63 that contains developers of four colors, magenta, cyan, and black, and forms a toner image corresponding to the electrostatic latent image on the image carrier 61, and 1 that transfers the toner image on the image carrier 61 A secondary transfer device 62; a belt-like intermediate transfer member 50 to which a toner image on the image carrier 61 is transferred; a secondary transfer device 51 to transfer the toner image of the intermediate transfer member 50; and a toner of the intermediate transfer member 50. A constant for fixing the toner image on the recording medium to which the image is transferred. A device 80 further comprises a cleaning device 64 for removing the toner remaining after transfer on the image carrier 61. The recording medium is conveyed from one of the paper feeding devices 21 and 22 that store the recording medium one by one to the registration roller 23 through the conveyance path by the conveyance roller. Here, the recording medium is synchronized with the toner image on the image carrier 61. Measured and transferred to the transfer position.

  As shown in FIGS. 4 and 5, the exposure device 70 in the image forming apparatus 300 irradiates the image carrier 61 charged by the charging device 100 with light, and electrostatically charges the image carrier 61 having photoconductivity. A latent image is formed. The light L may be a lamp such as a fluorescent lamp or a halogen lamp, or a laser beam by a semiconductor element such as an LED or LD. Here, an LD element is used when irradiation is performed in synchronization with the rotation speed of the image carrier 61 by a signal from an image processing unit (not shown). The developing device 63 has a developer carrying member, and the toner stored in the developing device 63 is conveyed to a stirring unit by a supply roller, mixed and stirred with a developer containing a carrier, and faces the image carrying member 61. To the developing area. At this time, the positively or negatively charged toner is transferred to the electrostatic latent image on the image carrier 61 and developed. The developer may be a magnetic or non-magnetic one-component developer or a combination thereof, or a wet developer.

  The primary transfer device 62 transfers the developed toner image on the image carrier 61 to the intermediate transfer member 50 by forming an electric field having a polarity opposite to the polarity of the toner from the back side of the intermediate transfer member 50. The primary transfer device 62 may be any one of a corotron, a scorotron corona transfer device, a transfer roller, and a transfer brush. Thereafter, the toner image is transferred onto the recording medium again by the transfer by the secondary transfer device 51 in synchronization with the recording medium conveyed from the paper feeding device 22. Here, the first transfer may be performed directly on the recording medium instead of the intermediate transfer member 50.

  The fixing device 80 heats and / or pressurizes the toner image on the recording medium to fix and fix the toner image on the recording medium. Here, the toner is passed through a pair of pressure and fixing rollers, and heat and pressure are applied at this time to fix the toner while melting the binder resin. The fixing device 80 may be in the form of a belt instead of a roller, or may be fixed by heat irradiation with a halogen lamp or the like. The cleaning device 64 for the image carrier 61 cleans and removes the toner remaining on the image carrier 61 without being transferred, thereby enabling the next image formation. The cleaning device 64 may be any system such as a blade made of rubber such as urethane or a fur brush made of fiber such as polyester.

  Hereinafter, the operation of the image forming apparatus 300 of the present invention will be described. The reading unit 30 sets a document on the document table of the document transport unit 36, or opens the document transport unit 36 to set a document on the contact glass 31, closes the document transport unit 36, and presses the document. Then, when a start switch (not shown) is pressed, the original is conveyed onto the contact glass 31 when the original is set on the original conveying section 36, and immediately after the original is set on the other contact glass 31, the first The reading traveling body and the second reading traveling bodies 32 and 33 are traveled. Then, light is emitted from the light source by the first reading traveling body 32 and reflected light from the document surface is further reflected toward the second reading traveling body 33 and reflected by the mirror of the second reading traveling body 33 to form an image. The image information is read through the lens 34 into the CCD 35 which is a reading sensor. The read image information is sent to this control unit. Based on the image information received from the reading unit 30, the control unit controls an LD (not shown) or an LED (not shown) disposed in the exposure device 70 of the image forming unit 60, and writes the laser toward the image carrier 61. Light L is irradiated. By this irradiation, an electrostatic latent image is formed on the surface of the image carrier 61.

  The paper feeding unit 20 feeds a recording medium from a multi-stage paper feeding cassette 21 by a paper feeding roller, separates the fed recording medium by a separation roller, sends it to a paper feeding path, and records it on the paper feeding path of the image forming unit 60. The medium is transported by a transport roller. In addition to the paper feeding unit 20, manual paper feeding is also possible, and a manual feed tray for manual feeding and a separation roller for separating the recording medium on the manual tray one by one toward the manual paper feed path are also provided on the side of the apparatus. I have. Each of the registration rollers 23 discharges only one recording medium placed on the paper feed cassette 21 and sends it to a secondary transfer unit positioned between the intermediate transfer member 50 and the secondary transfer device 51. When the image forming unit 60 receives image information from the reading unit 30, the image forming unit 60 forms a latent image on the image carrier 61 by performing the laser writing or the development process as described above.

  The developer in the developing device 63 is drawn up and held by a magnetic pole (not shown) to form a magnetic brush on the developer carrier. Further, the toner image is transferred to the image carrier 61 by a developing bias voltage applied to the developer carrier, and the electrostatic latent image on the image carrier 61 is visualized to form a toner image. As the developing bias voltage, an AC voltage and a DC voltage are superimposed. Next, one of the paper feed rollers of the paper feed unit 20 is operated to feed a recording medium having a size corresponding to the toner image. Along with this, one of the support rollers is rotationally driven by the drive motor, the other two support rollers are driven to rotate, and the intermediate transfer member 50 is rotated and conveyed. At the same time, the image carrier 61 is rotated by each image forming unit to form black, yellow, magenta, and cyan monochrome images on the image carrier 61, respectively. Then, as the intermediate transfer member 50 is transported, the monochrome images are sequentially transferred to form a composite toner image on the intermediate transfer member 50.

  On the other hand, one of the paper feed rollers of the paper feed unit 20 is selectively rotated, the recording medium is fed out from one of the paper feed cassettes 21, separated one by one by the separation roller, and put into the paper feed path, and the image is taken by the transport roller The recording medium is guided to the sheet feeding path in the image forming unit 60 of the forming apparatus 1 and the recording medium is abutted against the registration roller 23 and stopped. Then, the registration roller 23 is rotated in synchronization with the synthetic toner image on the intermediate transfer member 50, and the recording medium is sent to the secondary transfer portion which is a contact portion between the intermediate transfer member 50 and the secondary transfer device 51. The toner image is secondarily transferred by the influence of the secondary transfer bias and contact pressure formed in the secondary transfer portion, and the toner image is recorded on the recording medium. Here, the secondary transfer bias is preferably a direct current. The recording medium after the image transfer is sent to the fixing device 80 by the transport belt of the secondary transfer device, and the fixing device 80 fixes the toner image by applying pressure and heat by the pressure roller, and then the discharging roller 41. The paper is discharged onto the paper discharge tray 40.

  In the present embodiment, the charging member embodying the conductive member 101 has been mainly described. However, the conductive member 101 in the present invention may be used as a toner carrier or a transfer member as long as it does not contradict the purpose of the present invention. Absent.

Example 1
A resin composition was prepared by blending 25% by weight of ABS resin (GR-3000, manufactured by Denki Kagaku Kogyo Co., Ltd.) and 75% by weight of polyetheresteramide (IRGASTAT P18, manufactured by Ciba Specialty Chemicals Co., Ltd.). 4 parts of a polycarbonate-glycidyl methacrylate-styrene-acrylonitrile copolymer (Modiper CL440-G, manufactured by NOF Corporation) was added to the part, and melt-kneaded to obtain a resin melt composition. Then, this resin melt composition is injection-molded on a support (outer diameter 10 mm) made of SUM22 (Ni plating treatment) to form an electrical resistance adjustment layer. After adjusting the thickness, a ring-shaped gap holding member composed of a high-density polyethylene resin (Novatech PP HY540, manufactured by Nippon Polychem Co., Ltd.) having an outer diameter of 13 mm is press-fitted into both ends, and then the gap holding member Were simultaneously cut to 12.54 mm and the outer diameter of the electric resistance adjusting portion was 12.40 mm to obtain a roller. And on the surface of the electric resistance adjusting layer of the roller, 1) 40 parts by weight of an acrylic-modified silicone resin (3000VH-P, manufactured by Kawakami Paint Co., Ltd.), 2) an average molecular weight of 3000, an EO amount of 80% by weight and a length of 3 functional groups The chain polyether polyol resin (Exenol 3040, manufactured by Asahi Glass Co., Ltd.) and the short chain polyether polyol resin (Exenol 551, manufactured by Asahi Glass Co., Ltd.) having an average molecular weight of 1000, an EO amount of 80% by weight and a functional group number of 2 are 1: 1. 35% by weight of polyether polyol resin mixed by weight ratio, 3) 20% by weight of isocyanate resin (T4 curing agent, manufactured by Kawakami Paint Co., Ltd.), 4) Dissolved solution of lithium butyl acetate bis (trifluoromethane) sulfonylimidoate (Sanko Chemical) 5% by weight, manufactured by Kogyo Co., Ltd.) 5) Organic salt catalyst (U-CAT SA1, manufactured by San Apro) 0.5 layer After a solid content is adjusted by diluting a coating composition containing a resin composition consisting of a quantity% [weight% based on the total resin corresponding to 1) to 4) with a diluent solvent consisting of butyl acetate and MEK, spray By coating, a surface layer having a thickness of about 10 μm is formed, and subsequently, this surface layer is heated and cured in an oven at 100 ° C. for 1.5 hours, whereby a step of about 40 μm is formed between the gap holding member and the surface layer. Thus, a roller-like conductive member (charging member) having a shape formed thereon was obtained.

(Example 2)
The paint to be spray-coated on the surface of the electric resistance adjusting layer in the roller is applied to the surface of the electric resistance adjusting layer in the roller: 1) 20% by weight of acrylic-modified silicone resin (3000VH-P, Kawakami Paint Co., Ltd.), 2) average A long-chain polyether polyol resin (EXCENOL 3040, manufactured by Asahi Glass Co., Ltd.) having a molecular weight of 3000, an EO amount of 80% by weight and a functional group number of 3 and a short-chain polyether polyol resin having an average molecular weight of 1000, an EO amount of 80% by weight and a functional group number of 2 Polyether polyol resin 55% by weight mixed with Exenol 551 (Asahi Glass Co., Ltd.) at a weight ratio of 1: 1, 3) isocyanate resin (T4 curing agent, Kawakami Paint Co., Ltd.) 20% by weight, 4) bis ( Trifluoromethane) sulfonylimido lithium butyl acetate solution (manufactured by Sanko Chemical Co., Ltd.) 5% by weight, and 5% Except that the organic salt catalyst (U-CAT SA1, manufactured by San Apro) 0.5% by weight [% by weight based on the total resin corresponding to 1) to 4)] was used, except that the resin composition was used. In the same manner as in Example 1, a conductive member (charging member) was obtained.

(Example 3)
The paint to be spray-coated on the surface of the electric resistance adjusting layer in the roller is applied to the surface of the electric resistance adjusting layer in the roller: 1) acrylic modified silicone resin (3000VH-P, manufactured by Kawakami Paint Co., Ltd.), 2) average molecular weight 2000, A long-chain polyether polyol resin (Exenol 540, manufactured by Asahi Glass Co., Ltd.) having an EO amount of 40% by weight and 2 functional groups, an average molecular weight of 1000, an EO amount of 80% by weight and a short-chain polyether polyol resin having 2 functional groups (Exenol 551, Asahi Glass Co., Ltd.) and polyether polyol resin mixed at a weight ratio of 1: 1, 3) Isocyanate resin (T4 curing agent, Kawakami Paint Co., Ltd. 20% by weight, 4) Bis (trifluoromethane) sulfonyl 5% by weight of lithium butyl imidoate solution (manufactured by Sanko Chemical Co., Ltd.) and 5) organic salt catalyst ( -CAT SA1, manufactured by San Apro) 0.5% by weight [Wt% relative to all resins corresponding to 1) to 4)], except that the resin composition was used. Thus, a conductive member (charging member) was obtained.

Example 4
The paint to be spray-coated on the surface of the electric resistance adjusting layer in the roller is applied to the surface of the electric resistance adjusting layer in the roller: 1) 20% by weight of acrylic-modified silicone resin (3000VH-P, Kawakami Paint Co., Ltd.), 2) average A long-chain polyether polyol resin having a molecular weight of 2000, an EO amount of 40% by weight and a functional group number of 2 (Excenol 540, manufactured by Asahi Glass Co., Ltd.), a short-chain polyether polyol resin having an average molecular weight of 1000, an EO amount of 80% by weight and a functional group number of 2 Polyether polyol resin 55% by weight mixed with Exenol 551 (Asahi Glass Co., Ltd.) at a weight ratio of 1: 1, 3) isocyanate resin (T4 curing agent, Kawakami Paint Co., Ltd.) 20% by weight, 4) bis ( Trifluoromethane) sulfonylimidolithium butylacetate solution (5% by weight from Sanko Chemical Co., Ltd., 5) Except that the salt composition (U-CAT SA1, manufactured by San Apro) 0.5% by weight [% by weight based on the total resin corresponding to 1) to 4)] was used, except that the resin composition was used. In the same manner as in Example 1, a conductive member (charging member) was obtained.

(Comparative Example 1)
The paint to be spray-coated on the surface of the electric resistance adjusting layer in the roller is applied to the surface of the electric resistance adjusting layer in the roller: 1) 20% by weight of acrylic-modified silicone resin (3000VH-P, Kawakami Paint Co., Ltd.), 2) average Polyether polyol resin 55% by weight consisting of a long-chain polyether polyol resin (Excenol 3040, manufactured by Asahi Glass Co., Ltd.) having a molecular weight of 3000, an EO content of 80% and a functional group number of 3; 3) an isocyanate resin (T4 curing agent, manufactured by Kawakami Paint Co., Ltd.) 20% by weight, 4) 5% by weight of bis (trifluoromethane) sulfonylimido lithium butyl acetate solution (manufactured by Sanko Chemical Co., Ltd.), and 5) organic salt catalyst (U-CAT SA1, manufactured by San Apro). Containing a resin composition comprising 5% by weight [% by weight relative to all resins corresponding to the above 1) to 4)]; A conductive member (charging member) was obtained in the same manner as in Example 1 except that.

(Comparative Example 2)
The paint to be spray-coated on the surface of the electric resistance adjusting layer in the roller is applied to the surface of the electric resistance adjusting layer in the roller: 1) 20% by weight of acrylic-modified silicone resin (3000VH-P, Kawakami Paint Co., Ltd.), 2) average Polyether polyol resin 55% by weight composed of a short-chain polyether polyol resin (Excenol 551, manufactured by Asahi Glass Co., Ltd.) having a molecular weight of 1000, an EO amount of 80% by weight, and 2 functional groups, 3) an isocyanate resin (T4 curing agent, manufactured by Kawakami Paint Co., Ltd.) 20% by weight, 4) 5% by weight of bis (trifluoromethane) sulfonylimido lithium butyl acetate solution (manufactured by Sanko Chemical Co., Ltd.), and 5) organic salt catalyst (U-CAT SA1, manufactured by San Apro). 5% by weight [weight% based on the total resin corresponding to 1) to 4)] A conductive member (charging member) was obtained in the same manner as in Example 1 except that.

(Comparative Example 3)
The paint to be spray-coated on the surface of the electric resistance adjusting layer in the roller is applied to the surface of the electric resistance adjusting layer in the roller: 1) 20% by weight of acrylic-modified silicone resin (3000VH-P, Kawakami Paint Co., Ltd.), 2) average A long-chain polyether polyol resin having a molecular weight of 3000, an EO amount of 80% by weight and a functional group number of 3 (Exenol 3040, manufactured by Asahi Glass Co., Ltd.), and an average molecular weight of 2000, an EO amount of 40% by weight and a functional group number of 2 Polyether polyol resin 55% by weight mixed with Exenol 540 (manufactured by Asahi Glass Co., Ltd.) at a weight ratio of 1: 1, 3) isocyanate resin (T4 curing agent, Kawakami Paint Co., Ltd.) 20% by weight, 4) bis ( Trifluoromethane) sulfonylimido lithium butyl acetate solution (manufactured by Sanko Chemical Co., Ltd.) 5% by weight, and 5% Except that the organic salt catalyst (U-CAT SA1, manufactured by San Apro) 0.5% by weight [% by weight based on the total resin corresponding to 1) to 4)] was used, except that the resin composition was used. In the same manner as in Example 1, a conductive member (charging member) was obtained.

(Comparative Example 4)
The paint to be spray-coated on the surface of the electric resistance adjusting layer in the roller is applied to the surface of the electric resistance adjusting layer in the roller: 1) 20% by weight of acrylic-modified silicone resin (3000VH-P, Kawakami Paint Co., Ltd.), 2) average A short-chain polyether polyol resin (Excenol 551, manufactured by Asahi Glass Co., Ltd.) having a molecular weight of 1000, an EO amount of 80% by weight and a functional group number of 2, and a short-chain polyether polyol resin having an average molecular weight of 400, an EO amount of 80% by weight and a functional group number of 2 EXCENOL 540 (manufactured by Asahi Glass Co., Ltd.) and 55% by weight of a polyether polyol resin mixed at a 1: 1 weight ratio, 55% by weight of a polyether polyol resin mixed at a 1: 1 weight ratio, and 3) isocyanate Resin (T4 curing agent, Kawakami Paint Co., Ltd.) 20% by weight, 4) Bis (trifluoromethane) sulfonylimide acid 5% by weight of a solution of butyl thium acetate (manufactured by Sanko Chemical Co., Ltd.) and 5) 0.5% by weight of an organic salt catalyst (U-CAT SA1, manufactured by San Apro Co., Ltd.) A conductive member (charging member) was obtained in the same manner as in Example 1 except that the resin composition was a resin composition comprising:

(Comparative Example 5)
The paint to be spray-coated on the surface of the electric resistance adjusting layer in the roller is applied to the surface of the electric resistance adjusting layer in the roller by 1) acrylic modified silicone resin (3000 VH-P, manufactured by Kawakami Paint Co., Ltd.) 40% by weight, 2) average A long-chain polyether polyol resin (EXCENOL 3040, manufactured by Asahi Glass Co., Ltd.) having a molecular weight of 3000, an EO amount of 80% by weight and a functional group number of 3 and a short-chain polyether polyol resin having an average molecular weight of 1000, an EO amount of 80% by weight and a functional group number of 2 Polyether polyol resin 25% by weight mixed with Exenol 551 (Asahi Glass Co., Ltd.) at a weight ratio of 1: 1, 3) isocyanate resin (T4 curing agent, Kawakami Paint Co., Ltd.) 20% by weight, 4) bis ( Trifluoromethane) sulfonylimido lithium butyl acetate solution (manufactured by Sanko Chemical Co., Ltd.) 5% by weight, and 5% Except that the organic salt catalyst (U-CAT SA1, manufactured by San Apro) 0.5% by weight [% by weight based on the total resin corresponding to 1) to 4)] was used, except that the resin composition was used. In the same manner as in Example 1, a conductive member (charging member) was obtained.

(Comparative Example 6)
The paint to be spray-coated on the surface of the electric resistance adjusting layer in the roller is applied to the surface of the electric resistance adjusting layer in the roller by 1) acrylic modified silicone resin (3000 VH-P, manufactured by Kawakami Paint Co., Ltd.) 40% by weight, 2) average A long-chain polyether polyol resin having a molecular weight of 2000, an EO amount of 40% by weight and a functional group number of 2 (Excenol 540, manufactured by Asahi Glass Co., Ltd.), a short-chain polyether polyol resin having an average molecular weight of 1000, an EO amount of 80% by weight and a functional group number of 2 3) Polyether polyol resin mixed with Exenol 551 (Asahi Glass Co., Ltd.) at a weight ratio of 1: 1, 3) Isocyanate resin (T4 curing agent, Kawakami Paint Co., Ltd.) 20% by weight, 4) Bis ( Trifluoromethane) sulfonylimido lithium butyl acetate solution (manufactured by Sanko Chemical Co., Ltd.) 5% by weight, and 5) Except for the one containing a resin composition consisting of an organic salt catalyst (U-CAT SA1, manufactured by San Apro) [weight% based on the total resin corresponding to the above 1) to 4)], the same as in Example 1 Thus, a conductive member (charging member) was obtained.

  In Comparative Examples 1 and 2, the long-chain and short-chain polyether polyol resins used in Example 1 are used alone. The comparative examples 3 and 4 are respectively used in combination of a long chain and a long chain, and a short chain and a short chain polyether polyol resin. In Comparative Examples 1 to 4, as shown in Table 1 below, sufficient hardness cannot be obtained. In Comparative Examples 5 and 6, a polyether polyol resin is combined in the same manner as in Examples 1 and 3, but the content ratio of the polyether polyol resin in all the resins constituting the surface layer is changed. Represents a reduced content of the polyether polyol resin.

  As described above, the following tests 1 to 3 were evaluated for the conductive members (charging rollers) obtained in Examples 1 to 5 and Comparative Examples 1 to 6.

<Test 1> (Color spot image evaluation)
The color spot image evaluation was performed as follows. The ABS resin powder is spread to a thickness of 2 mm, and the conductive members (charging rollers) obtained in Examples 1 to 5 and Comparative Examples 1 to 6 are placed on the ABS resin powder, and the conductive support portions are 5 mm thick. The ABS resin powder was forced to adhere to the entire circumference of the charging roller by its own weight, and then the ABS resin powder was lightly tapped and dropped twice or three times. Then, the charging roller having the ABS resin powder adhered thereto obtained in Examples 1 to 5 and Comparative Examples 1 to 6 is mounted on a process cartridge (see FIG. 3), and this is mounted on an image forming apparatus (imageMP C4500, Rico). -After the mounting (see FIGS. 4 and 5), the voltage applied to the charging roller was set to DC = -700 V, AC = 2.2 kVpp (frequency = 2.2 kHz) as an initial agent. Next, 10 A3, 1 × 1 halftone images are output by the image forming apparatus, and each color spot image evaluation (color spot occurrence state: confirmation of which spot the spot color disappears) is performed. It was.

<Test 2> (Image evaluation after continuous copying)
Image evaluation after continuous copying was performed as follows. The conductive member (charging roller) obtained in Examples 1 to 5 and Comparative Examples 1 to 6 is mounted on a process cartridge (see FIG. 3), and this is formed into an image forming apparatus (imageMP C4500, manufactured by Rico Corporation) ( 4), the initial voltage was set to DC = −700 V and AC = 2.2 kVpp (frequency = 2.2 kHz). Next, in a room temperature environment of 23 ° C. and 60% RH, the presence or absence of an abnormal roller image (partial charging failure) after passing 30000 A3, 1 × 1 halftone images with the image forming apparatus was confirmed.

<Test 3> (Evaluation of surface layer hardness)
Evaluation of the hardness (universal hardness) (HU value) of the surface layer was performed as follows. For evaluation of the hardness (universal hardness) of this surface layer, a microhardness measuring device Fischer scope (manufactured by Fischer) was used. A profile showing the indentation depth under a load of 5 mN applied to a Vickers square pyramid diamond indenter with a facing angle of 136 ° for 10 seconds can be obtained by the micro scope measuring device Fischer scope. . The vertical axis represents the indentation depth H [μm], and the horizontal axis represents the load F [mN]. The universal hardness is defined by the quotient of the applied test force and the surface area of the dent generated by the application. The indentation surface area is calculated from the indentation depth that is pushed in with the applied test force. When using a Vickers indenter, the universal hardness is given by
Universal hardness = test load [N] / surface area of Vickers indenter at test load [mm ² ] = F / 26.43 h ²
It is represented by However, the measurement conditions were an indentation amount of 5: mmN / 10 sec, an indentation time of 10 seconds, and a creep of 2 seconds, and the measurement locations were 5 in the axial direction and 4 mm intervals from the center of the roller. It was a place.

   The evaluation criteria for the evaluation were as follows.

(1) Color spot image evaluation ◎ 10 × 1 × 1 halftone images are output and no color spot occurs in the meantime. × 1 × 1 halftone image is output even if 10 × 1 halftone images are output. Will not disappear

(2) Image evaluation after continuous copying ◎: Even if a halftone image is output after continuous copying, there is no uneven image due to black spots or charging unevenness. △: After a continuous copying, a halftone image is output. No more than 10 uneven images due to black spots and charging unevenness per sheet. ×: Even if halftone images are output after continuous copying, uneven images due to black spots and uneven charging are per sheet. More than 10 locations

(3) Comprehensive evaluation ◎: Both color spot image evaluation and image evaluation after continuous copying are acceptable in practice. ×: One or both of color spot image evaluation and image evaluation after continuous copying are not practically acceptable. The evaluation results are shown in the following Table 1.

  Table 1 shows the following. That is, according to Test 1, the charging rollers of Examples 1 to 4 and Comparative Examples 5 and 6 are cleaned during the initial agent setting or during the image evaluation because the attached ABS resin is cleaned. Abnormal images of color spots and black spots caused by the adhered ABS resin powder were at acceptable levels. However, since the charging rollers of Comparative Examples 1 to 4 are not sufficiently cleaned during initial agent setting or during image evaluation, abnormal images of color spots and black spots caused by the attached ABS resin powder are at an acceptable level. Did not reach. According to Test 2, the charging rollers of Examples 1 to 4 were able to obtain good images even after passing 100,000 sheets, but the charging rollers of Comparative Examples 1 to 4 were contaminated on the roller surface and adhered substances. Since the removal property was poor, color spots, black spots, and streak images were confirmed. Since the charging rollers of Comparative Examples 5 and 6 have a small amount of polyether, the charging ability tends to be low initially. For this reason, uneven charging occurs due to contamination of the roller surface over time, and the charging function of the charging roller. An abnormal image of color spots and black spots and unevenness images due to the low margin of the image occurred, and as a result, the allowable level was not reached. And according to Test 3, although it is a reference value, when the universal hardness is 9 mm / N or more, the effect of removing the resin powder is confirmed.

DESCRIPTION OF SYMBOLS 1 Conductive support body 2 Electrical resistance adjustment layer 3 Surface layer 4 Gap holding member 5 Bearing 6 Pressure spring (pressure member)
61 Image carrier (photoconductor)
100 Charging Device 101 Conductive Member (Charging Member, Charging Roller)
102 Cleaning member 200 Process cartridge G Micro gap 300 Image forming apparatus

Japanese Patent Laid-Open No. 3-240076 JP-A-4-358175 JP-A-5-107871 JP-A-2005-91818 JP 2009-42550 A

Claims (8)

In a conductive member having a conductive support, an electrical resistance adjustment layer provided on the conductive support, and a surface layer formed on the electrical resistance adjustment layer,
(A) The surface layer is a) a polyether polyol resin, b) a polyol resin grafted with silicon, c) a fluorine-containing organic anion containing an alkali metal or an alkaline earth metal, and d) poly Composed of a crosslinking reaction product of a resin composition containing isocyanate, and
(B) The polyether polyol resin is composed of a short-chain polyether polyol resin having an average molecular weight of 400 to 1000 and a long-chain polyether polyol resin having an average molecular weight of 2000 to 3000. Element.   The long-chain polyether polyol resin is contained at a content ratio equal to that of the short-chain polyether polyol resin or a content ratio greater than the content ratio of the short-chain polyether polyol resin. The conductive member according to 1.   3. The conductive member according to claim 1, wherein the polyether polyol resin is contained at a ratio of 35 to 55 wt% with respect to the total resin constituting the surface layer.   The conductive member according to any one of claims 1 to 3, wherein a content of the polyether in terms of ethylene oxide in the polyether polyol resin is 40 to 80% by weight.   5. A ring-shaped gap holding member that is in contact with the image carrier and forms a fixed minute gap is provided at both ends of the conductive member. The electroconductive member as described in.   A charging device comprising the conductive member according to claim 1 as a charging member. In the process cartridge in which the image carrier and the charging device are integrally supported and are detachably fixed to the main body of the image forming apparatus.
A process cartridge comprising the charging device according to claim 6. A process cartridge; exposure means for exposing the surface of the image carrier to form an electrostatic latent image; developing means for supplying toner to the electrostatic latent image on the surface of the image carrier for visualization; and the image carrier In an image forming apparatus comprising at least transfer means for transferring a visualized image of the surface of the body to a transfer medium,
An image forming apparatus comprising the process cartridge according to claim 6.

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