JP4807842B2 - Elastic roller, method for manufacturing elastic roller, fixing device for image forming apparatus, and image forming apparatus - Google Patents

Description

The present invention relates to an elastic roller, a method of manufacturing an elastic roller, a fixing device for an image forming apparatus, and an image forming apparatus. More specifically, for example, the image forming apparatus can be used for an image forming apparatus. The present invention relates to an elastic roller that contributes to improving the durability of the toner, a manufacturing method thereof , a fixing device for an image forming apparatus including such an elastic roller, and an image forming apparatus including such an elastic roller.

  Various types of image forming apparatuses using an electrophotographic system are employed in laser printers, copiers, video printers, facsimiles, and complex machines of these. An image forming apparatus using an electrophotographic system includes a shaft body and an elastic layer formed on an outer peripheral surface thereof, for example, a cleaning roller, a charging roller, a developing roller, a transfer roller, a pressure roller, a paper feed conveyance roller, Various rollers such as a fixing roller are provided. In such an image forming apparatus, in order to form a high-quality image, various rollers mounted on the image forming apparatus are required to have uniform characteristics in the axial direction.

  These various rollers usually form an elastic layer by molding the rubber composition around the shaft body by various molding methods. Preferably, in order to reliably crosslink the rubber composition, the molded elastic layer is further formed. Is produced by secondary heating. However, when a rubber composition is molded by an extrusion molding method or the like, especially when the molded elastic layer is subsequently subjected to secondary heating, the vicinity of the central portion of the finally formed elastic layer is heated from its peripheral side surface. Both end portions are heated from the end surface in addition to the peripheral side surface. Therefore, the finally formed elastic layer may have different cross-linking ratios or the like of the rubber composition in the vicinity of the center portion and in the vicinity of both end portions. On the other hand, when a rubber composition is molded using a mold, and particularly when the molded elastic layer is secondarily heated using a mold, the expansion of the rubber composition or the molded elastic layer due to heating is large at the center of the mold. In the same manner as in the extrusion method, the elastic layer finally formed is different in the vicinity of the central portion and the cross-linking ratio of the rubber composition in the vicinity of both end portions. Sometimes. Thus, if the cross-linking ratio of the rubber composition in the vicinity of the central portion of the elastic layer to be finally formed is different from that in the vicinity of both ends, the vicinity of the central portion of the elastic layer to be finally formed and the vicinity of both ends. The physical properties, such as hardness, may not be uniform over the axial direction of the elastic layer. When a roller having an elastic layer having non-uniform physical properties in the axial direction is attached to the image forming apparatus, not only the image quality is deteriorated but also the elastic layer of the roller is uniformly contacted. There is a problem that the durability of the roller and / or the object to be abutted is deteriorated.

  On the other hand, a roller having a difference in hardness between the central portion and the end portion of the roller has been proposed (see, for example, Patent Documents 1 and 2). Specifically, Japanese Patent Application Laid-Open No. H10-228867 describes that “the difference in the hardness of the rubber material between the both end portions and the central portion of the roller for the fixing device is provided, and the hardness of the central portion is larger than the hardness of the both end portions. "Fixing device roller" is described. Further, in claim 1 of Patent Document 2, “in a heat roller type fixing device having a fixing roller and a pressure roller that is brought into pressure contact with the fixing roller, at least one of the fixing roller and the pressure roller is provided. A fixing device in which roller configuration conditions are made different between a sheet passing area and a non-sheet passing area is described. Claim 2 of Patent Document 2 describes "the non-sheet passing area of the at least one roller". The fixing device according to claim 1, wherein the hardness of the fixing device is smaller than the hardness of the sheet passing area.

  The roller for the fixing device and the fixing roller or the pressure roller (hereinafter referred to as the roller of the cited document) of the fixing device are rollers that solve the problems peculiar to the fixing device. Even if it is arranged in the image forming apparatus, it cannot contribute to high definition of the image and durability of the image forming apparatus. For example, the roller is disposed in the image forming apparatus so that the roller is deformed. For example, the fixing roller or the like maintains the deformed state in the rest state of the image forming apparatus. When the roller of the cited document having a hardness difference is used as a fixing roller or the like, the restoring force of the deformed roller to return to the original state varies depending on the hardness difference, resulting in deformation unevenness in the axial direction of the roller. The developer cannot be reliably fixed to the transfer member, and the image quality may be deteriorated. In addition, the roller of the cited document has different hardness at the center and the end, so even if it is installed in a recent image forming apparatus, either the center or the end wears quickly with respect to the other. May deteriorate.

JP-A-7-64424 JP-A-10-111614

INDUSTRIAL APPLICABILITY The present invention can be used in an image forming apparatus, and forms an image of high quality and contributes to improving the durability of the image forming apparatus, its manufacturing method , and forms an image of high quality and forms an image. It is an object of the present invention to provide a fixing device for an image forming apparatus that contributes to improving the durability of the apparatus, and an image forming apparatus excellent in durability that can form a high-quality image.

As means for solving the problems,
Claim 1 is an elastic roller comprising a shaft and an elastic layer formed by molding an addition reaction type foamed silicone rubber composition on the outer peripheral surface thereof, and is provided in an image forming apparatus, wherein the addition reaction type The foamed silicone rubber composition contains a vinyl group-containing silicone raw rubber, a silica-based filler, a foaming agent, an addition reaction crosslinking agent, an addition reaction catalyst, and a reaction control agent, and in the vicinity of the central portion in the axial direction of the elastic layer. An elastic roller characterized in that the hardness is larger than the hardness in the vicinity of both ends and the hardness difference is 2 or less in Asker C hardness,
Claim 2, wherein the elastic layer is an elastic roller according to claim 1, characterized in that it has a thickness of 2 to 20 mm,
The elastic roller according to claim 1 or 2 , wherein the elastic roller is a fixing roller that fixes the developer transferred to the transfer target.
Claim 4 is a method for producing an elastic roller according to any one of claims 1 to 3 , wherein the vinyl group-containing silicone raw rubber, silica-based filler, foaming agent, and addition reaction crosslinking agent. And an addition reaction-type foamed silicone rubber composition containing an addition reaction catalyst and a reaction control agent, and a shaft so that the length is 109% or more and less than 165% with respect to the axial length of the elastic layer of the elastic roller. In addition, the step of extruding, the step of secondary heating without using a mold in the extruded state of the addition reaction type foamed silicone rubber composition, and the uncut elasticity formed by the step of secondary heating Cutting each end of the layer so as to have the axial length, an elastic roller manufacturing method,
A fifth aspect of the present invention is a fixing device for an image forming apparatus including the elastic roller according to the third aspect ,
A sixth aspect of the present invention is an image forming apparatus including the elastic roller according to the third aspect .

  Since the elastic roller according to the present invention includes an elastic layer having a small difference in Asker C hardness in the axial direction and having substantially uniform hardness, when disposed in the image forming apparatus, the elastic roller is at a predetermined pressure and It abuts against a body to be abutted such as an image carrier uniformly in the axial direction of the elastic roller. Therefore, since the elastic roller according to the present invention can act uniformly on the abutted body in the axial direction, the elastic roller can sufficiently contribute to the formation of a high-quality image and can be elastic. It is possible to sufficiently contribute to the improvement of the durability of the image forming apparatus without causing uneven wear or the like in the roller and / or the contacted body. For example, when the elastic roller according to the present invention is used as at least one of the pressure roller and the fixing roller in the fixing device provided in the image forming apparatus, the elastic roller according to the present invention is used at a predetermined pressure and in the axial direction of the elastic roller. The developer (electrostatic latent image) transferred to the transfer body can be uniformly heated and / or pressurized by being brought into contact with or pressed against the transfer body such as transfer paper uniformly, and uneven wear on the elastic roller, etc. Therefore, it is possible to sufficiently contribute to the formation of a high-quality image and to sufficiently contribute to the improvement of the durability of the image forming apparatus.

  As shown in FIG. 1, the elastic roller according to the present invention includes a shaft body 2 and an elastic layer 3 formed on the outer peripheral surface thereof. Preferably, as shown in FIG. And a tube layer 4 formed on the outer peripheral surface, and disposed in, for example, the image forming apparatus 30 shown in FIG.

  The shaft body 2 only needs to have good conductive properties, and is usually a so-called “core” made of iron, aluminum, stainless steel, brass, or the like. Further, the shaft body 2 may be a shaft body that is made conductive by plating an insulating core body such as a thermoplastic resin or a thermosetting resin. Furthermore, the shaft body 2 may be a thermoplastic resin or a thermosetting resin. The shaft body may be formed of a conductive resin in which carbon black or metal powder is blended as a conductivity imparting agent.

  The elastic layer 3 is formed on the outer peripheral surface of the shaft body 2 by a rubber composition described later. The elastic layer 3 may be a foamed elastic layer having bubbles in the inside and / or the outer surface thereof, or may be an elastic layer having no bubbles, and depending on various rollers used in the image forming apparatus, The presence / absence, size, presence rate, etc. of bubbles are determined. For example, when the elastic rollers 1A and 1B (hereinafter, both may be referred to as the elastic roller 1) are used as the fixing roller, the elastic roller 3 is deformed by being pressed against the pressure roller. It is preferable that one elastic layer 3 is a foamed elastic layer because a high-quality image can be formed. In this case, a plurality of bubbles (not shown) included in the elastic layer 3 do not contact or communicate with other bubbles (referred to as a closed cell state) or contact other bubbles. Or in a communicating state (referred to as a communicating bubble state) or in a state where the closed bubble state and the communicating bubble state coexist.

  In the elastic layer 3, the hardness difference between the central portion vicinity 3A, the end portion vicinity 3B and the end portion vicinity 3C in the axial direction of the elastic layer 3 is 2 or less in Asker C hardness. If the difference in hardness between the central portion 3A and both end portions 3B and 3C is 2 or less in terms of Asker C hardness, the elastic layer 3 has a substantially uniform hardness in the axial direction thereof, and is therefore disposed in the image forming apparatus. In this case, a high-quality image can be formed by contacting or press-contacting a contacted body such as an image carrier or a transfer body uniformly at a predetermined pressure and in the axial direction of the elastic roller 1. Further, it is possible to sufficiently contribute to improving the durability of the image forming apparatus. The difference in hardness between the central portion 3A and both end portions 3B and 3C is 1 or less in Asker C hardness in that it can further contribute to improving the durability of high-quality image formation and the image forming apparatus. Is more preferable and 0 is particularly preferable.

  In the present invention, the central portion vicinity 3A, the end portion vicinity 3B and the end portion vicinity 3C are not particularly limited in their magnitude relationship as long as the hardness difference is satisfied. It may be larger or smaller than the hardness of the end vicinity 3B and the end vicinity 3C.

  The elastic layer 3 may have a hardness difference between the vicinity of the central portion 3A and the vicinity of both end portions 3B and 3C within the above range, but the shaft of the elastic layer 3 can be sufficiently exerted as an elastic roller. The central portion vicinity 3A in the direction and both end vicinity portions 3B and 3C of the elastic layer 3 are preferably 20-60 in terms of Asker C hardness, and particularly preferably 25-50.

  In this invention, the central portion vicinity 3A does not have to be the central portion in the axial direction of the elastic layer 3, and may be a portion having a width of, for example, about 10 mm around the central portion, for example, centering on the central portion. Similarly, both end portions 3B and 3C need not be both end portions in the axial direction of the elastic layer 3, but may be portions near each end, for example, a portion having a width of about 10 mm from each end, for example. Good. In the present invention, the Asker C hardness can be measured according to JIS K6253.

  The difference in Asker C hardness of the elastic layer 3 is, for example, by selecting the type of rubber and additive contained in the rubber composition forming the elastic layer 3 and / or by changing the content thereof. Can be adjusted.

  If the elastic layer 3 has the said hardness difference by Asker C hardness, it will not restrict | limit in particular regarding properties, such as intensity | strength, its material, thickness, etc. For example, the elastic layer 3 is adjusted to an arbitrary length according to the application. As an example, the elastic layer 3 is adjusted to about 310 mm when an A3 size paper (JIS, 297 mm × 420 mm) is used as a transfer object in a portrait orientation, and the A4 size (JIS, When a sheet of 210 mm × 297 mm) is used in a portrait orientation, it is adjusted to about 230 mm. Further, the thickness of the elastic layer 3 is determined according to various rollers used in the image forming apparatus, but it is usually preferable that the elastic layer 3 has a thickness of 2 to 20 mm.

  As shown in FIG. 2, a tube layer 4 may be formed on the outer peripheral surface of the elastic layer 3 as desired. When the tube layer 4 is formed on the outer surface of the elastic layer 3, the releasability of the developer can be improved. The tube layer 4 is formed to a thickness of 1 to 100 μm, for example.

  In the elastic roller 1, if desired, an adhesive layer, a primer layer, or the like may be provided between the shaft body 2 and the elastic layer 3, and, for example, on the outer peripheral surface of the elastic layer 3 or the tube layer 4, for example, A surface layer such as a protective layer may be provided.

  The elastic roller 1 may include a heating body, for example, an electric heater, a heating coil, or the like, in the shaft body 2, in the elastic layer 3, or between the shaft body 2 and the elastic layer 3, depending on the application. . For example, when the elastic roller 1 is used as a fixing roller of a heat roller fixing device, a heating body is provided.

  The elastic roller 1 having the elastic layer 3 having the Asker C hardness difference is obtained by heat-molding a rubber composition by continuous heat molding by extrusion molding, pressing, molding by injection, or the like, and on the outer peripheral surface of the shaft body 2. It is manufactured by a method of forming the elastic layer 3. As one preferred manufacturing method, for example, the rubber composition is thermoformed integrally with the shaft body 2 by an extrusion molding method, and each of the vicinity of both ends of the crosslinked uncut elastic layer has a desired final length, for example, The manufacturing method which cut | disconnects so that it may become the length as a product is mentioned.

  The rubber composition for forming the elastic layer 3 may be a composition containing rubber and, if desired, various additives, a foaming agent, and the like. For example, foamed silicone capable of forming closed-celled bubbles Preferred examples include rubber-based compositions and urethane foam rubber-based compositions. In particular, the foamed silicone rubber-based composition capable of forming closed-cell bubbles is a suitable rubber composition that is excellent in heat resistance, durability, resistance to residual strain, etc., and can withstand high-speed operation of an image forming apparatus. It is. As such a foamed silicone rubber composition, an addition reaction type foamed silicone rubber composition is particularly preferred.

  The addition reaction type foamed silicone rubber composition comprises a vinyl group-containing silicone raw rubber, a silica-based filler, a foaming agent, an addition reaction crosslinking agent, an addition reaction catalyst, a reaction control agent, and an organic peroxide as required. Contains a crosslinking agent and various additives.

  Examples of the vinyl group-containing silicone raw rubber include millable silicone rubber, heat-crosslinked silicone rubber (HVR) and the like. These vinyl group-containing silicone raw rubbers have the property that a foaming agent, a crosslinking agent, etc. can be easily kneaded with a roll mill or the like in a later step, and may be used alone or in combination of two or more. it can.

Examples of the silica-based filler include a fumed silica or a precipitated silica having a reinforcing property, and a surface having a high reinforcing effect that is surface-treated with a silane coupling agent represented by a general formula RSi (OR ′) _3. A treated silica-based filler is preferred. Here, R in the general formula is a glycidyl group, vinyl group, aminopropyl group, methacryloxy group, N-phenylaminopropyl group, mercapto group or the like, and R ′ in the general formula is a methyl group or an ethyl group. . The silane coupling agent represented by the general formula can be easily obtained, for example, as trade names “KBM1003” and “KBE402” manufactured by Shin-Etsu Chemical Co., Ltd. Such a silica-based filler surface-treated with a silane coupling agent can be obtained by treating the surface of the silica-based filler according to a conventional method. The compounding amount of the silica-based filler is preferably 5 to 100 parts by mass with respect to 100 parts by mass of the vinyl group-containing silicone raw rubber.

  The foaming agent may be any foaming agent conventionally used for foamed rubber. Examples of the inorganic foaming agent include sodium bicarbonate and ammonium carbonate. Examples of the organic foaming agent include diazoamino derivatives, azonitri derivatives, azo And organic azo compounds such as dicarboxylic acid derivatives. Usually, an inorganic foaming agent is used when forming open cells in rubber, and an organic foaming agent is used when forming closed cells. In the elastic roller 1, the foaming agent is preferably an organic foaming agent because it can form bubbles in a closed cell state. Specifically, for example, azodicarbonamide, azobis-isobutyro An azo compound such as nitrile is preferably used. In particular, dimethyl-1,1'-azobis (1-cyclohexanecarboxylate) can be preferably used. The content of the foaming agent varies depending on the type of foaming agent, but it is preferable to adjust the Asker C hardness of the elastic layer 3 to 20 to 60. Specifically, for example, it may be 0.1 to 10 parts by mass, particularly 0.5 to 10 parts by mass with respect to 100 parts by mass of the vinyl group-containing silicone raw rubber. If the content of the foaming agent is less than 0.1 parts by mass, sufficient bubbles may not be formed in the formed elastic layer 3, while if it exceeds 10 parts by mass, as foamed silicone rubber In this case, the mechanical strength of the elastic layer 3 may be reduced. When dimethyl-1,1′-azo-bis (1-cyclohexanecarboxylate) is selected as the foaming agent, the content thereof is 0.5 to 5 with respect to 100 parts by mass of the vinyl group-containing silicone raw rubber. The mass part is particularly good.

  As the addition reaction crosslinking agent, for example, a known organohydrogenpolysiloxane can be used as an addition reaction type crosslinking agent having two or more SiH groups (SiH bonds) in one molecule. The organohydrogenpolysiloxane may be linear, cyclic, or branched. The compounding amount of the organohydrogenpolysiloxane is preferably 0.01 to 20 parts by mass with respect to 100 parts by mass of the vinyl group-containing silicone raw rubber.

  The addition reaction catalyst includes, for example, a simple substance of Group 9 or 10 of the periodic table and a compound thereof, and more specifically, particulate platinum adsorbed on a carrier such as silica, alumina, or silica gel. Metals, platinum chloride, chloroplatinic acid, chloroplatinic acid hexahydrate and olefin or divinyldimethylpolysiloxane complexes, platinum-based catalysts such as chloroplatinic acid hexahydrate alcohol solutions, palladium catalysts, rhodium catalysts, etc. Can be mentioned. The addition amount of these addition reaction catalysts is sufficient as the catalyst amount, and is usually 1 in terms of the total amount of addition reaction type foamed silicone rubber composition in terms of the metal amount of Group 9 or Group 10 of the Periodic Table. It is good that it is -1,000 ppm, and it is especially good that it is 10-500 ppm. If the amount of addition reaction catalyst is less than 1 ppm in terms of the metal content of Group 9 or Group 10 of the Periodic Table, the crosslinking reaction of vinyl group-containing silicone raw rubber does not proceed sufficiently, and vinyl group-containing silicone Curing of the raw rubber may be insufficient. On the other hand, if it exceeds 1,000 ppm, the ability to accelerate the crosslinking reaction of the vinyl group-containing silicone raw rubber is not improved, and the economic efficiency may be lowered.

  As the reaction control agent, known reaction control agents can be used without limitation, and examples thereof include methylvinylcyclotetrasiloxane, acetylene alcohols, siloxane-modified acetylene alcohol, and hydroperoxide. The compounding amount of the reaction control agent is preferably 0.1 to 2 parts by mass with respect to 100 parts by mass of the vinyl group-containing silicone raw rubber.

  The organic peroxide cross-linking agent can be used alone to cross-link vinyl group-containing silicone raw rubber, but if used in combination as an auxiliary cross-linking agent for an addition reaction cross-linking agent, the physical properties of the silicone rubber, such as strength and strain, can be improved. improves. Examples of the organic peroxide crosslinking agent include benzoyl peroxide, bis-2,4-dichlorobenzoyl peroxide, dicumyl peroxide, di-t-butyl peroxide, and 2,5-dimethyl-2,5-bis. (T-butylperoxy) hexane and the like. The compounding amount of the organic peroxide crosslinking agent is preferably 0.3 to 10 parts by mass with respect to 100 parts by mass of the vinyl group-containing silicone raw rubber.

  The various additives include, for example, carbon black such as acetylene black, furnace black, channel black, filler such as calcium carbonate, colorant, heat resistance improver, flame retardant improver, heat conductivity improver, etc. Agents, mold release agents, alkoxysilanes, diphenylsilanediols, carbon functional silanes, dispersants such as both-end silanol-blocked low molecular siloxanes, and crushed quartz, diatomaceous earth, etc. that can adjust the hardness of the resulting rubber Non-reinforcing silica is exemplified. These various additives are blended in a desired blending amount.

  As the silicone rubber composition containing the vinyl group-containing silicone raw rubber, the silica filler, and the various additives, for example, trade names “KE series” and “KEG series” manufactured by Shin-Etsu Chemical Co., Ltd. can be easily used. It can be obtained.

  The rubber composition is used, for example, for several minutes to several hours, preferably 5 minutes, until it is uniformly mixed using a rubber kneader such as a two-roll, three-roll, roll mill, Banbury mixer, and dounixa (kneader). It is obtained by kneading at room temperature or under heating for 1 minute to 1 hour.

  The material for forming the tube layer 4 is not particularly limited, but the elastic roller 1B is preferably in contact with or pressed against the contacted body, and thus is preferably a material that is not easily permanently deformed. For example, alkyd resin , Alkyd resin modified products such as phenol modified / silicone modified, oil free alkyd resin, acrylic resin, silicone resin, epoxy resin, fluororesin, phenol resin, polyamide resin, urethane resin, polyamideimide resin, and mixtures thereof It is done.

  In the manufacturing method of the elastic roller 1, first, an adhesive or a primer is applied to the outer peripheral surface of the shaft body 2 in advance as necessary by a spray method, a dipping method, or the like, and an adhesive layer is applied to the outer peripheral surface. Alternatively, a primer layer is preferably formed. The primer is not particularly limited, and examples thereof include a silane coupling primer. Further, the adhesive is not particularly limited, but for example, an adhesive having an amino group and / or a hydroxyl group is suitable. Examples thereof include, for example, alkyd resins, phenol-modified / silicone-modified alkyd resin modified products, oil-free alkyd resins, acrylic resins, silicone resins, epoxy resins, fluororesins, phenol resins, polyamide resins, urethane resins, and mixtures thereof. Is mentioned. Moreover, an isocyanate compound, a melamine compound, an epoxy compound, a peroxide, a phenol compound, a hydrogensiloxane compound, etc. are used as a crosslinking agent for curing these resins.

  Next, the rubber composition adjusted as described above is extruded together with the shaft body 2 on which the adhesive layer or the primer layer is formed. At this time, the rubber composition is preferably extruded to a length of 109 to 190%, and preferably 120 to 150% of the final length of the elastic layer. Particularly preferred. When the rubber composition is extruded so as to have a length in the above range, the physical properties, for example, the hardness, etc., of the vicinity of both ends and the center of the uncut elastic layer formed by curing the rubber composition are uniform. Even if it does not occur, an elastic layer having substantially uniform physical properties such as hardness can be formed by cutting the vicinity of both ends of the uncut elastic layer. The length of the rubber composition to be extruded is set to 190% of the final length of the desired elastic layer in consideration of productivity, but the elastic layer has uniform physical properties. In order to form the film, the upper limit is not necessarily 190%, and may be 200% or 300%.

  When extruding a rubber composition, if the total length of the shaft body is shorter than the length of the rubber composition to be extruded, an extension shaft body may be connected to both ends of the shaft body. Specifically, a female screw is cut at each end face at both ends of the shaft body, a male screw that is screwed into the female screw is cut at one end face of the extension shaft body, and the female screw and the male screw are screwed together. It can be a connected shaft.

  Extrusion molding of the rubber composition may be performed under conditions sufficient for the rubber contained in the rubber composition, for example, a vinyl group-containing silicone raw rubber to be crosslinked, and when the rubber composition contains a foaming agent, What is necessary is just to carry out on conditions sufficient for rubber | gum to bridge | crosslink and a foaming agent to decompose | disassemble or foam. For example, the extrusion molding of the rubber composition is usually performed at 100 to 500 ° C., particularly 200 to 400 ° C., and the heating time is several minutes or more by a heating furnace such as an infrared heating furnace or a hot air furnace, a heating machine such as a dryer, etc. This is done by heating for a period of time, especially 5-30 minutes.

  If desired, the rubber composition may be further subjected to secondary heating. The secondary heating is a step of more reliably crosslinking the rubber composition crosslinked under the above conditions, and the effect of stabilizing the physical properties of the elastic layer 3 is obtained by the secondary heating. In the secondary heating, for example, the rubber composition obtained by extrusion molding under the above-described conditions is further kept in the extruded state, for example, 180 to 250 ° C., preferably 190 to 230 ° C., 1 to 24 Over a period of time, preferably 3 to 10 hours, or using a mold, for example, 130 to 200 ° C., preferably 150 to 180 ° C., for 5 minutes to 24 hours, preferably 10 minutes to 10 hours, This is done by heating again.

  Next, the uncut elastic layer formed in this manner is cut in the vicinity of both ends of the uncut elastic layer so as to be an elastic layer having a desired final length. That is, the vicinity of both end portions of the uncut elastic layer is cut and adjusted to the final length of the elastic layer. At this time, it is preferable that the vicinity of both ends of the uncut elastic layer to be cut is cut with the same length. For example, when the uncut elastic layer is formed with a length of 109% with respect to the final length of the desired elastic layer, each end of the uncut elastic layer is cut by a total of 9%. Preferably, it is only necessary to cut 4.5% from each end by 9% in total, and when the length is 190% of the final length of the desired elastic layer, Each end of the cut elastic layer may be cut by 90% in total, and preferably 45% from each end may be cut by 90% in total. The uncut elastic layer may be cut by a method that can cut the uncut elastic layer. For example, a cutting machine equipped with a cutting blade such as a cutter, more specifically, a side cut machine is used. The uncut elastic layer can be cut.

  The uncut elastic layer or the elastic layer having both ends cut as described above is subjected to a grinding step and / or a polishing step, etc., which are adjusted to a desired size and shape as a finishing step, if desired. . The grinding step and / or the polishing step can be performed according to a conventional method using a conventionally used grinder, cylindrical grinder, file or the like. Further, after the grinding step and / or the polishing step, the uncut elastic layer or the elastic layer may be washed as desired in order to remove the grinding residue, polishing residue, foreign matter, and the like. Examples of the cleaning include wet cleaning using water and / or wiping cleaning using waste or the like, blowing cleaning, and the like.

  Next, the tube layer 4 is formed on the outer peripheral surface of the elastic layer 3 as desired. The tube layer 4 is formed on the outer surface of the elastic layer 3 by inserting the elastic layer 3 into a tubular body previously formed of a cylindrical material having the same inner diameter as the outer diameter of the elastic layer 3. It is preferable in that the tube layer 4 having a smooth surface can be formed without being greatly affected by the uneven shape present on the surface of the elastic layer 3. Of course, the tube layer 4 may be formed by applying the material to the outer peripheral surface of the elastic layer 3 according to, for example, a dipping method or a spray method, and then curing and / or crosslinking.

  Furthermore, if desired, a protective layer or the like can be formed on the outer peripheral surface of the elastic layer 3 or the tube layer 4 according to a standard method.

  In this way, the elastic roller 1 having the elastic layer 3 in which the difference in hardness between the central portion vicinity 3A and the both end portions 3B and 3C in the axial direction is 2 or less in Asker C hardness is manufactured.

  That is, in the elastic roller 1 manufactured in this way, the difference in hardness between the central portion vicinity 3A and the both ends vicinity 3B and 3C is 2 or less in Asker C hardness, and the rubber composition contains a foaming agent. In this case, since the elastic layer 3 in which bubbles are uniformly formed is provided, various rollers of the image forming apparatus such as a transfer roller, a developing roller, a charging roller, a fixing roller, a pressure roller, a paper feed roller, etc. Particularly, it is preferably used for a fixing roller.

  In particular, when the elastic roller 1 is disposed in the image forming apparatus, the elastic roller 1 comes into contact with a contacted body such as an image carrier uniformly at a predetermined pressure and in the axial direction of the elastic roller 1. Therefore, since the elastic roller 1 can act uniformly on the contacted body in the axial direction, the elastic roller 1 can sufficiently contribute to forming a high-quality image and It is possible to contribute to the improvement of the durability of the image forming apparatus without causing uneven wear.

  For example, when the elastic roller 1 is used as at least one of the pressure roller and the fixing roller in the fixing device provided in the image forming apparatus, the elastic roller 1 is uniformly distributed over the axial direction of the elastic roller 1 with a predetermined pressure. The developer (electrostatic latent image) transferred to the transfer body can be uniformly heated and / or pressurized by pressing the transfer body such as transfer paper, and uneven wear or the like in the elastic roller 1 may occur. Therefore, the image forming apparatus can sufficiently contribute to the formation of a high-quality image and can sufficiently contribute to the improvement of the durability of the image forming apparatus. Further, when the elastic roller 1 is used as a fixing roller disposed so that the roller is deformed in the image forming apparatus or the fixing apparatus, the fixing roller is deformed in a rest state of the image forming apparatus or the fixing apparatus. Even if the state is maintained, since the elastic roller 1 has the difference in Asker C hardness between the central portion 3A and the end portions 3B and 3C of the elastic layer 3 within the above range, the restoring force of the elastic layer 3 is uniform. As a result, the restored state of the elastic layer 3 becomes uniform, the developer can be reliably fixed to the transfer body, and a high-quality image can be formed.

  In addition, when the elastic roller 1 is used as a developing roller disposed so as to contact an image carrier provided in a recent image forming apparatus, the elastic roller 1 is used with a predetermined pressure and in the axial direction. Since the developer can be uniformly abutted on the image carrier and the developer can be adhered to the image carrier with a uniform thickness with high accuracy, it can sufficiently contribute to the formation of a high-quality image and the image. It can also contribute sufficiently to improving the durability of the forming apparatus.

  Next, a fixing device (hereinafter sometimes referred to as a fixing device according to the present invention) including an elastic roller according to the present invention and an image forming device (hereinafter referred to as an image forming device according to the present invention) may be referred to. ) Will be described with reference to FIG.

  As shown in FIG. 3, the image forming apparatus 30 according to the present invention includes a rotatable image carrier 31 on which an electrostatic latent image is formed, for example, a photosensitive member, and a contact with the image carrier 31 or a predetermined interval. A charging means 32 for charging the image carrier 31, for example, a charging roller, an exposure means 33 provided above the image carrier 31 to form an electrostatic latent image on the image carrier 31, and an image carrier A developing means 40 that is provided in contact with the body 31 or at a predetermined interval, supplies the developer 42 with a constant layer thickness to the image carrier 31, and develops the electrostatic latent image; A transfer means 34 for transferring the developed electrostatic latent image from the image carrier 31 onto a transfer target 36 such as a transfer sheet, and a transfer roller, and a downstream of the transfer target 36 in the conveying direction. Developer 42 (electrostatic latent) provided and transferred to the transfer target 36 ) Fixing means 35, for example, a fixing device, and a cleaning means 37 for removing the developer 42 not transferred to the transfer target 36 and / or remaining on the image carrier 31 and / or dust adhering to the image carrier 31. I have. That is, the image carrier 31 is subjected to each action by the cleaning unit 37, the charging unit 32, the exposure unit 33, the developing unit 40, and the transfer unit 34 in order from the upstream side in the rotation direction.

  The image carrier 31 can be a conventionally known image carrier, and at least the photosensitive layer provided on the surface thereof is made of, for example, an organic material, amorphous silicon, a Se alloy, or a combination thereof. It is formed. When the image carrier 31 is cylindrical, the image carrier 31 can be manufactured by a known production method such as a method of forming a photosensitive layer or the like on the surface after extrusion molding of aluminum or an aluminum alloy. It is also possible to use a belt-like image carrier. The charging means 32 only needs to be able to charge the image carrier 31. For example, a contact charger using a conductive or semiconductive roller, brush, film, rubber blade, etc., a scorotron using corona discharge. A charger such as a charger or a corotron charger can be used. Among these, a contact-type charger is preferable in terms of excellent charge compensation capability. The exposure means 33 only needs to be able to form an electrostatic latent image on the image carrier 31 by exposure. For example, a semiconductor laser (LD) light, a light emitting diode (LED) light, a liquid crystal is formed on the surface of the image carrier 31. Light sources such as shutter (LCS) light, or optical equipment that can be exposed in a desired image form from these light sources through a polygon mirror can be used. The transfer means 34 only needs to be able to transfer the developed electrostatic latent image from the image carrier 31 onto the transfer paper 36. For example, a contact-type transfer charger using a belt, a roller, a film, a rubber blade, or the like. A scorotron transfer charger using a corona discharge, a corotron transfer charger, or the like can be used. Among these, a contact type transfer charger is preferable in that it has excellent transfer charge compensation capability. In addition to the transfer charger, a peeling charger can be used in combination. As the cleaning means 37, it is sufficient that the developer 42 and / or dust on the image carrier 31 can be removed, and a known cleaning device, a cleaning roller, or the like can be used.

  The fixing unit 35 only needs to fix the developer 42 (electrostatic latent image) transferred to the transfer target 36. For example, a heat roller fixing device including a fixing roller capable of generating heat, an oven fixing device, and the like. A heat fixing device, a pressure fixing device provided with a pressurizing fixing roller, and the like can be used. These fixing devices may be fixing devices having endless belts. In FIG. 3, a fixing means 35 having an endless belt is the fixing device according to the present invention. As shown in FIG. 3, the fixing device 35 includes a fixing roller 53 and an endless belt disposed in the vicinity of the fixing roller 53 in a housing 50 having an opening 52 through which the transfer target 36 passes. A support roller 54, an endless belt 55 wound around the fixing roller 53 and the endless belt support roller 54, and a pressure roller 56 disposed to face the fixing roller 53, and the fixing roller 53 via the endless belt 55. This is a pressure heat fixing device in which the pressure roller 56 is rotatably supported so as to abut against or press against each other. The endless belt support roller 54 may be a roller that is normally used in an image forming apparatus. For example, an elastic roller or the like is used. For example, the endless belt 55 may be an endless belt formed of a resin such as polyamide or polyamideimide, and the thickness of the endless belt 55 may be appropriately adjusted to match the fixing unit 35. Each of the fixing roller 53, the endless belt support roller 54, and the pressure roller 56 includes a heating body (not shown), and the pressure roller 56 causes the endless belt 55 to be moved by a biasing means (not shown) such as a spring. Via the fixing roller 53. By passing the transferred material 36 between the endless belt 55 and the pressure roller 56, the developer 42 (electrostatic latent image) transferred to the transferred material 36 is heated at the same time as being pressed. It can be fixed.

  The image forming apparatus 30 includes a neutralizing unit (not shown) for removing an electrostatic latent image remaining on the surface of the image carrier 31 between the cleaning unit 37 and the charging unit 32 or the transfer unit 34 and the cleaning unit. 37 may be provided. For example, a tungsten lamp, an LED, or the like can be used as the static elimination means. Examples of the light quality used for the optical static elimination means include white light such as a tungsten lamp, red light such as LED light, and the like. In general, the output is set so as to be about several to thirty times the amount of light indicating the half exposure sensitivity of the image carrier 31.

  The developing means 40 in the image forming apparatus 30 is basically formed in the same manner as the developing means provided in the conventional image forming apparatus, and is arranged in the same manner. For example, as shown in FIG. 3, the developing unit 40 has an opening at a position facing the image carrier 31, a developer storage unit 41 that stores the developer 42, and an opening of the developer storage unit 41. A rotatable developer carrier 44 provided in contact with the image carrier 31 or at a predetermined interval, and supplying a developer 42 with a constant layer thickness to the image carrier 31; A rotatable developer supply means 43 that supplies the developer 42 to the developer carrier 44 and a developer carrier 44 that is provided above the developer carrier 44 and contacts the developer carrier 44. A developer regulating member 45 that regulates the layer thickness of the developer 42 and charges the developer 42 by frictional charging.

  The developer accommodated in the developer accommodating portion 41 is a one-component developer that can be charged by friction and can be fixed to the transfer target 36, even if it is a dry developer, a wet developer. It may be a non-magnetic developer or a magnetic developer. The one-component developer generally includes a resin, a colorant, and other additives, and the resin is selected according to the fixing method. In the case of the heat fixing method, as the resin, for example, a styrene / acrylic copolymer or a styrene / butadiene copolymer, and in the case of the pressure fixing method, for example, a wax or an ethylene / vinyl acetate copolymer. Styrene / butadiene rubber mixed waxy resin or the like is selected. Examples of the colorant include carbon black, magnetite, various dyes and pigments, and examples of other additives include a charge control agent, a conductivity control agent, a reinforcing agent, and a release agent. In the case of a magnetic developer, magnetic powder such as ferrite is further contained by several tens of mass% with respect to the total mass of the developer 42. One-component developers usually have a charging characteristic of about 2 to 8 μC / g.

  The developer supply means 43 in the developing means 40 may be configured so that the developer 42 can be supplied to the developer carrying body 44 by contacting the developer carrying body 44. And a developing roller having an elastic layer. Note that a stirrer that uniformly mixes the developer 42 supplied to the developer carrier 44 may be provided in the developer container 41.

  The developer carrier 44 in the developing unit 40 comes into contact with the developer regulating member 45 to charge the developer 42. Accordingly, it is sufficient that the developer carrier 44 is configured to be able to charge the developer 42 by contacting the developer regulating member 45. For example, the developing roller provided with an elastic layer having conductivity. Etc. For example, the elastic roller 1 according to the present invention can be used as such a developer carrier 44, particularly as a developing roller.

  As shown in FIG. 3, the developer regulating member 45 is disposed in the opening of the developing unit 40 so as to come into contact with the surface of the developer carrier 44 with a predetermined pressure. The developer regulating member 45 may be in contact with the developer carrier 44 to adjust the developer 42 attached to the developer carrier 44 to a certain layer thickness and to charge the developer 42. For example, the support member and a blade attached to the support member and in contact with the developer carrier 44 may be used. The support is made of an elastic material, such as stainless steel, supports the blade, and makes the blade contact the developer carrier 44 with an appropriate pressure. The blade is formed of an elastic material such as stainless steel or an elastic thin plate, contacts the developer carrier 44, regulates the layer thickness of the developer 42, and develops by frictional charging. The agent 42 is charged. The blade may have a surface layer (not shown) for charging the developer 42 on the surface thereof.

  The image forming apparatus 30 according to the present invention includes a charging roller of the charging unit 32, a developing roller of the developing unit 40, a transfer roller of the transfer unit 34, a fixing roller of the fixing unit 35, a pressure roller or an endless belt support roller, and a cleaning unit. Various rollers such as a cleaning roller and a paper feeding / conveying roller are provided, and the elastic roller 1 according to the present invention is used as at least one of these various rollers. Preferably, the elastic roller 1 according to the present invention is used as at least one of a charging roller, a developing roller, a transfer roller, a fixing roller, and a pressure roller.

  The image forming apparatus 30 according to the present invention operates as follows. First, in the image forming apparatus 30, the developer 42 and / or dust on the surface thereof are removed by the cleaning unit 37 while the image carrier 31 rotates clockwise as indicated by the arrow in FIG. 3. Thereafter, it is uniformly charged by the charging means 32. Next, the image is exposed by the exposure means 33, and an electrostatic latent image is formed on the surface of the image carrier 31.

  On the other hand, in the developing means 40, the developer 42 is supplied to the developer carrier 44 by the developer supply means 43, and the developer carrier 44 rotates in the direction of the arrow shown in FIG. The developer 42 adhered to the surface of the toner passes between the developer carrier 44 and the developer regulating member 45 in contact with the developer carrier 44. At this time, the developer 42 is regulated to a desired layer thickness, and the developer 42 can be charged as desired. That is, as the developer 42 passes between the developer carrier 44 and the developer regulating member 45, the layer thickness of the developer 42 on the surface of the developer carrier 44 is regulated, and the developer The developer 42 on the developer carrier 44 is charged as desired by frictional charging between the regulating member 45 and the developer carrier 44 and / or the developer 42.

  Next, the developer 42 having a desired layer thickness and charge amount is supplied from the developing means 40 to the image carrier 31 in this way, and the electrostatic latent image formed on the image carrier 31 is developed. The electrostatic latent image is visualized as a developer image. In this way, the developing unit 40 can supply the developer 42 having a desired layer thickness and charge amount to the image carrier 31 to develop the electrostatic latent image. Subsequently, the developer image developed on the image carrier 31 is transferred to the image carrier 31 and / or transferred onto the transfer medium 36 conveyed between the image carrier 31 and the transfer unit 34 by the conveying unit. Transferred by means 34. Next, the transfer material paper 36 onto which the developer image has been transferred is conveyed to the fixing unit 35 by the conveying unit, and heated and / or pressurized by the fixing unit 35, so that the transferred developer image is covered as a permanent image. It is fixed on the transfer body 36. In this way, an image can be formed on the transfer target 36.

  The image forming apparatus 30 according to the present invention includes at least one of various rollers such as a charging roller, a developing roller, a transfer roller, a fixing roller, a pressure roller, an endless belt support roller, a cleaning roller, and a paper feed / conveying roller. Since the elastic roller 1 according to the present invention is used, the roller using the elastic roller 1 according to the present invention can act uniformly on the abutted body in the axial direction, and is of high quality. It is possible to sufficiently contribute to forming an image. For example, when the elastic roller 1 according to the present invention is used as the developing roller 44 disposed so as to be in contact with the image carrier 31, the image is uniformly applied at a predetermined pressure and in the axial direction of the developing roller 44. Since the developer 42 can be adhered to the image carrier 31 with a uniform thickness and with high accuracy, it can sufficiently contribute to the formation of a high-quality image.

  In the image forming apparatus 30 according to the present invention, the image carrier 31, the charging unit 32, the exposure unit 33, the transfer unit 34, the fixing unit 35, and the cleaning unit 37 are arranged in addition to the arrangement shown in FIG. The image carrier, the charging unit, the exposure unit, the transfer unit, the fixing unit and the cleaning unit provided in the apparatus may be formed in the same manner and arranged in the same manner.

  The image forming apparatus 30 is an electrophotographic image forming apparatus. However, in the present invention, the image forming apparatus is not limited to the electrophotographic system, and is, for example, an electrostatic image forming apparatus. May be. Further, the image forming apparatus 30 is a monochrome image forming apparatus in which the developing unit 40 contains only a single color developer 42. However, in this invention, the image forming apparatus is not limited to a monochrome image forming apparatus. It may be an image forming apparatus. Examples of the color image forming apparatus include a four-cycle color image forming apparatus that sequentially repeats primary transfer of a developer image carried on an image carrier to an intermediate transfer body, and a plurality of image carriers provided with developing means for each color. Examples thereof include a tandem type color image forming apparatus in which a body is arranged in series on an intermediate transfer body or a transfer conveyance belt. The image forming apparatus 30 is an image forming apparatus such as a copying machine, a facsimile machine, or a printer.

  In the image forming apparatus 30, a one-component developer is advantageously used as the developer 42, but a two-component developer including a toner and a carrier such as iron or nickel can also be used. . The two-component developer usually has a charging characteristic of about 10 to 25 μC / g.

(Example 1)
First, an electroless nickel-plated shaft (diameter 12 mm x length 300 mm, SUM22) was washed with toluene, and primer “No. 101A / B” (manufactured by Shin-Etsu Chemical Co., Ltd .: trade name) was applied. did. The primer-treated shaft body was fired at a temperature of 180 ° C. for 30 minutes using a gear oven, and then cooled at room temperature for 30 minutes or more to form a primer layer.

  Subsequently, 100 parts by mass of a silicone rubber composition “KE-904FU” (manufactured by Shin-Etsu Chemical Co., Ltd .: trade name) containing a vinyl group-containing silicone raw rubber and a silica-based filler, and an addition reaction crosslinking agent “C-153A” ( Shin-Etsu Chemical Co., Ltd .: trade name) 2.0 parts by mass, foaming agent “KEP-13” (Shin-Etsu Chemical Co., Ltd .: trade name) 3.0 parts by mass, and an appropriate amount of platinum catalyst as an addition reaction catalyst And an appropriate amount of a reaction control agent and an appropriate amount of “C-3” (manufactured by Shin-Etsu Chemical Co., Ltd .: trade name) as an organic peroxide cross-linking agent are sufficiently kneaded with two rolls, and an addition reaction type foaming A silicone rubber composition was prepared.

  Next, the length of the addition reaction type foamed silicone rubber composition to be dispensed is 260 mm (the final length of the desired elastic layer (230 mm). 113%)), and is integrally dispensed by an extruder so that the thickness is about 5 mm, and then heated at 250 ° C. for 10 minutes using an infrared heating furnace (IR furnace) to foam. Crosslinking was performed, and the diameter of the addition reaction type foamed silicone rubber composition after the foam crosslinking was adjusted to about 35 mm. Then, the addition reaction type | mold foaming silicone rubber composition after foaming bridge | crosslinking was further heated for 7 hours at 200 degreeC using the gear oven, and was left to stand at normal temperature for 1 hour. In this way, a roller on which an uncut elastic layer having a length of 260 mm was formed was produced. In the roller, the vicinity of both ends of the uncut elastic layer is cut by 15 mm (6.5% with respect to the final length of the elastic layer) by using a side cut machine, and then elasticated by a cylindrical grinder. The layer diameter was ground to 30 mm. Thus, the elastic roller provided with the elastic layer which has a length of 230 mm was produced.

(Reference Example 1)
An uncut elastic layer formed by the addition reaction type foamed silicone rubber composition is extruded to obtain a length of 430 mm (187% with respect to a desired final length of the elastic layer (230 mm)). In the same manner as in Example 1 except that the vicinity of both end portions of the uncut elastic layer was cut by 100 mm (43.5% with respect to the final length of the elastic layer), the elastic layer having a length of 230 mm. An elastic roller with a layer was produced. In addition, the extension shaft body of length 85mm was connected to the both ends of the shaft body, and the full length was 470 mm.
(Example 2)
The uncut elastic layer formed by the addition reaction type foamed silicone rubber composition is extruded to obtain a length of 340 mm (110% with respect to the final length (310 mm) of the desired elastic layer). An elastic layer having a length of 310 mm was obtained in the same manner as in Example 1 except that the vicinity of both ends of the uncut elastic layer was cut by 15 mm (5% with respect to the final length of the elastic layer). The provided elastic roller was produced. In addition, the shaft body used the shaft body which forms a primer layer similarly to Example 1, and has the full length of 380 mm.
(Reference Example 2)
An uncut elastic layer formed by the addition reaction type foamed silicone rubber composition is extruded to obtain a length of 510 mm (165% with respect to the final length (310 mm) of the desired elastic layer). Elasticity having a length of 310 mm was obtained in the same manner as in Example 1 except that the vicinity of both ends of the uncut elastic layer was cut by 100 mm (32.2% with respect to the final length of the elastic layer). An elastic roller with a layer was produced. In addition, the shaft body produced in Example 3 was used for the shaft body, the extension shaft body of length 85mm was connected to the both ends, and the full length was 550 mm.
Example 3
The uncut elastic layer formed by the addition reaction type foamed silicone rubber composition is extruded to obtain a length of 260 mm (113% with respect to the final length (230 mm) of the desired elastic layer). The vicinity of one end of the uncut elastic layer is cut by 10 mm (4.3% with respect to the final length of the elastic layer), and the vicinity of the other end is 20 mm (8. 8 with respect to the final length of the elastic layer). 7%) An elastic roller provided with an elastic layer having a length of 230 mm was produced in the same manner as in Example 1 except that it was cut.
(Reference Example 3)
Example 1 Except that an uncut elastic layer having a length of 260 mm produced in the same manner as in Example 1 was formed and then subjected to secondary heating at 150 ° C. for 15 minutes by press molding using a mold. In the same manner as described above, an elastic roller provided with an elastic layer having a length of 230 mm was produced.

(Comparative Example 1)
The uncut elastic layer formed by the addition reaction type foamed silicone rubber composition is 230 mm (100% with respect to the final length (230 mm) of the desired elastic layer) and obtained by extrusion molding. An elastic roller provided with an elastic layer having a length of 230 mm was prepared in the same manner as in Example 1 except that the vicinity of both ends of the uncut elastic layer was not cut.
(Comparative Example 2)
The uncut elastic layer formed by the addition reaction type foamed silicone rubber composition is obtained by extrusion molding so that the length of the uncut elastic layer is 310 mm (100% with respect to the final length (310 mm) of the desired elastic layer). An elastic roller provided with an elastic layer having a length of 310 mm was prepared in the same manner as in Example 1 except that the vicinity of both ends of the uncut elastic layer was not cut. In addition, the shaft body used the shaft body which forms a primer layer similarly to Example 1, and has the full length of 380 mm.
(Comparative Example 3)
An uncut elastic layer formed of the addition reaction type foamed silicone rubber composition is extruded to obtain a length of 246 mm (107% with respect to the final length (230 mm) of the desired elastic layer). In the same manner as in Example 1 except that the vicinity of both end portions of the uncut elastic layer was cut by 8 mm (3.5% with respect to the final length of the elastic layer), an elastic layer having a length of 230 mm. An elastic roller with a layer was produced.
(Comparative Example 4)
An uncut elastic layer formed of the addition reaction type foamed silicone rubber composition is extruded to obtain a length of 332 mm (107% with respect to the final length (310 mm) of the desired elastic layer). In the same manner as in Example 1 except that the vicinity of both end portions of the uncut elastic layer was cut by 11 mm (3.5% with respect to the final length of the elastic layer), the elastic layer having a length of 310 mm. An elastic roller with a layer was produced. In addition, the shaft body used the shaft body which forms a primer layer similarly to Example 1, and has the full length of 380 mm.

  The Asker C hardness at the center and both ends of the elastic layer 3 in the elastic roller thus produced was measured by the above method, and the difference in Asker C hardness between the center and both ends of the elastic layer 3 was calculated. In addition, when the Asker C hardness and the Asker C hardness difference in the both ends are different (Example 5), the numerical values in the respective ends are described.

The durability of the elastic rollers produced in Examples 1 to 3 and Reference Examples 1 to 3 and Comparative Examples 1 to 4 was tested using the durability test apparatus 70 shown in FIG. 4 by the following method. This durability test apparatus 70 is fixed to the lower surface inside the casing, and includes a heating roller 71 provided with an internal heater 72, and external heaters 73 provided on both sides of the heating roller 71 along the axial direction. A test roller mounting portion 74 provided on the upper surface inside the housing so as to be movable up and down so as to face the heating roller 71, and a pressing force adjusting means 75 capable of moving the test roller mounting portion 74 up and down, for example, pressure adjustment A micrometer. As the heating roller 71, a metal (stainless steel, SUS304) roller having a diameter of 20 mm was used.

The elastic rollers produced in Examples 1 to 3 and Reference Examples 1 to 3 and Comparative Examples 1 to 4 are mounted on the bearing of the test roller mounting portion 74, and the pressing force adjusting means 75 is operated as shown in FIG. Then, the mounted elastic roller 76 is pressed against the heating roller 71, and the elastic roller 76 is fixed so that the elastic layer of the elastic roller 76 is recessed 3 mm inside at the pressure contact portion between the heating roller 71 and the elastic roller 76. (That is, the distance d between the central axis of the elastic roller 76 and the central axis of the heating roller 71 was adjusted to be 3 mm shorter than the sum of the outer diameter of the elastic roller 76 and the outer diameter of the heating roller 71.)

  Next, the external heater 73 and the internal heater 72 were started, and the surface temperature of the heating roller 71 was adjusted to 180 ° C. Thereafter, the driving means (not shown) provided in the test roller mounting part 74 is continuously operated for 8 hours at a rotational speed of 130 rpm, and after the elastic layer 76 is released from the recessed state of the elastic layer, the elastic roller 76 is kept at room temperature for 24 hours. Left for hours.

As a result, the elastic rollers produced in Examples 1 to 3 and Reference Examples 1 to 3 had no deformation unevenness over the axial direction of the elastic layer after the test, and uneven wear or the like of the elastic layer could not be confirmed. Therefore, based on this result, when the elastic rollers produced in Examples 1 to 3 and Reference Examples 1 to 3 are disposed in the image forming apparatus, they act uniformly on the contacted body in the axial direction. Therefore, it was found that the image forming apparatus can sufficiently contribute to the formation of a high-quality image and can also contribute to the improvement of the durability of the image forming apparatus. On the other hand, the elastic rollers produced in Comparative Examples 1 to 4 were able to confirm deformation deformation and / or uneven wear of the elastic layer after the test. Therefore, it is understood that the elastic rollers manufactured in Comparative Examples 1 to 4 cannot sufficiently contribute to the improvement of the image quality and the improvement of the durability of the image forming apparatus when disposed in the image forming apparatus. It was.

FIG. 1 is a perspective view showing an example of an elastic roller. FIG. 2 is a perspective view showing an example of an elastic roller. FIG. 3 is a schematic view of the essential portions showing an example of the image forming apparatus according to the present invention. FIG. 4 is a schematic diagram showing a durability test apparatus.

Explanation of symbols

1A, 1B, 76 Elastic roller 2 Shaft body 3 Elastic layer 3A Near central part 3B, 3C Near end part 4 Tube layer 30 Image forming apparatus 31 Image carrier 32 Charging means 33 Exposure means 34 Transfer means 35 Fixing means 36 Transfer object 37 Cleaning means 40 Developing means 41 Developer container 42 Developer 43 Developer supply means 44 Developer carrier 45 Developer regulating member 50 Housing 52 Opening 53 Fixing roller 54 Endless belt support roller 55 Endless belt 56 Pressure roller 70 Durability test device 71 Heating roller 72 Internal heater 73 External heater 74 Test roller mounting portion 75 Pressing force adjusting means

Claims (6)

An elastic roller comprising a shaft and an elastic layer formed by molding an addition reaction type foamed silicone rubber composition on an outer peripheral surface thereof, and disposed in an image forming apparatus,
The addition reaction type foamed silicone rubber composition contains a vinyl group-containing silicone raw rubber, a silica-based filler, a foaming agent, an addition reaction crosslinking agent, an addition reaction catalyst, and a reaction control agent, and
An elastic roller characterized in that the hardness in the vicinity of the central portion in the axial direction of the elastic layer is larger than the hardness in the vicinity of both ends, and the difference in hardness is 2 or less in Asker C hardness. The elastic roller according to claim 1 , wherein the elastic layer has a thickness of 2 to 20 mm. Said elastic roller has an elastic roller according to claim 1 or 2, characterized in that a fixing roller for fixing the developer transferred onto a transfer member. It is a manufacturing method of the elastic roller which manufactures the elastic roller of any one of Claims 1-3 ,
An elastic layer of the elastic roller comprising an addition reaction type foamed silicone rubber composition containing a vinyl group-containing silicone raw rubber, a silica-based filler, a foaming agent, an addition reaction crosslinking agent, an addition reaction catalyst, and a reaction control agent, and a shaft. A step of extrusion molding such that the length is 109% or more and less than 165% with respect to the axial length of
A step of secondary heating without using a mold in an extruded state of the addition reaction type foamed silicone rubber composition;
A method of manufacturing an elastic roller, comprising: cutting both end portions of the uncut elastic layer formed in the secondary heating step so as to have the axial length. A fixing device for an image forming apparatus, comprising the elastic roller according to claim 3 . An image forming apparatus comprising the elastic roller according to claim 3 .

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