JP5608336B2 - Elastic roller and fixing device - Google Patents

Description

  The present invention relates to an elastic roller and a fixing device. More specifically, the present invention relates to an elastic roller having high heating efficiency and exhibiting a desired function for a long period of time, and a high heating efficiency for fixing a developer on a recording medium for a long period of time. The present invention relates to a fixing device that can be used.

  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.

  Among these rollers, for example, a fixing roller and a pressure roller have a large nip width by contacting the fixing roller and the pressure roller with a predetermined pressure for the purpose of fixing the developer on the recording medium. It is demanded that it can be secured over a long period of time.

  In recent years, it has become a major goal to promote speeding up and power saving of image forming apparatuses. As one means for achieving this goal, it has been proposed to improve the heat insulation of the fixing roller and / or the pressure roller mounted on the fixing device of the image forming apparatus.

  However, in order to secure a large nip width between the fixing roller and the pressure roller, the hardness of the elastic layer formed on the fixing roller and / or the pressure roller is usually reduced. As a result, the durability of the elastic layer is lowered, and the developer may not be fixed to the recording material for a long period of time.

  In order to enhance the heat insulation of the fixing roller and / or the pressure roller, a space or a hollow portion that exhibits a heat insulating function may be formed in the elastic layer of the fixing roller and / or the pressure roller. If these spaces or hollow portions are formed, the hardness of the elastic layer itself is lowered, and it may be impossible to fix the developer to the recording medium for a long time.

  Thus, in the elastic layer of the fixing roller and the pressure roller, durability and heat insulation are in a trade-off relationship, and it has been strongly demanded to satisfy both of these characteristics.

For example, Patent Document 1 discloses a “pressure roller” with improved heat insulation as a technique related to a film heating type heat fixing device and a pressure roller used in a heat roller type heat fixing device. Specifically, Patent Document 1 states that “a pressure roller in which an elastic layer and a release layer are formed on the outer periphery of a core metal in this order from the inside, and the elastic layer includes an inorganic micro hollow body. Describes a pressure roller made of silicone rubber. Further, in Patent Document 1, in the pressure roller, “the roller hardness (ASKER-C) is not less than 46 ° and not more than 60 °” (see claim 4), and “the heat conduction of the elastic layer” The rate is 3 × 10 ⁻⁴ (cal / cm · ° C. · sec) or less ”(see claim 5 etc.).

In a direct heating type fixing device that includes a pressure roller and a heating roller provided with a heater for heating and does not have an endless belt wound around them, the diameter and surface temperature of the pressure roll are controlled. As a technique for improving the fixability by making it easy to perform, Patent Document 2 describes, “A heating roll having a heater for heating inside, and a pressure roll having an elastic layer on an outer peripheral portion in pressure contact with the heating roll. A fixing device of an electrophotographic copying machine for fixing a toner image on a paper sandwiched between both rolls while pressing the heating roll and the pressure roll, wherein the elastic layer of the pressure roll has a thermal conductivity. ^{8 × 10 -4 ~30 × 10 -4} (cal / cm · sec · ℃) fixing device of an electrophotographic copying machine, characterized by being configured with a silicone-based rubber material "has been described . The elastic layer of the pressure roll is adjusted to a very high thermal conductivity in order to facilitate temperature control in a direct heating type fixing device. On the other hand, Patent Document 2 does not describe any technique related to an external heating type fixing device including a pressure roller that does not include a heater for heating and a heating roller.

JP 2001-65544 A JP-A 61-209472

  An object of the present invention is to provide an elastic roller having high heating efficiency and exhibiting an initial function over a long period of time.

  Another object of the present invention is to provide a fixing device having high heating efficiency and capable of fixing a developer on a recording material over a long period of time.

As means for solving the problems,
Claim 1 comprises a foamed elastic layer formed on the outer peripheral surface of the shaft body and containing 40 to 100 parts by mass of a silica-based filler with respect to 100 parts by mass of the silicone rubber and the silicone rubber, The foamed elastic layer is formed by pressing a cured rubber formed by foaming and curing a foamed silicone rubber composition containing silicone rubber and a silica-based filler, and the Asker C hardness of the foamed elastic layer. Is an elastic roller characterized in that it is smaller than the Asker C hardness of the rubber cured body and is 35 to 55, and its thermal conductivity is 0.09 to 0.175 (W / m · k),
According to a second aspect of the present invention, the fixing roller, the endless belt wound around the fixing roller, the pressure roller pressed against the fixing roller via the endless belt, and the endless belt are arranged in a non-contact manner. A fixing device comprising heating means for heating the fixing roller, wherein at least one of the fixing roller and the pressure roller is the elastic roller according to claim 1. is there.

  The elastic roller according to the present invention includes a foamed elastic layer containing silicone rubber and 40 to 100 parts by mass of a silica-based filler with respect to 100 parts by mass of the silicone rubber, and has an Asker C hardness of 35 to 55 and conducts heat. Although the rate is 0.09 to 0.175 (W / m · k), this foamed elastic layer can include a large amount of cells without damaging and exhibit high heating efficiency. A large nip pressure and nip width can be secured over a long period of time. Therefore, according to the present invention, it is possible to provide an elastic roller that has high heating efficiency and exhibits a desired function over a long period of time.

  According to the invention, since the fixing device according to the invention includes the elastic roller according to the invention, the fixing device having high heating efficiency and capable of fixing the developer onto the recording medium over a long period of time. Can be provided.

FIG. 1 is a perspective view showing an elastic roller of an embodiment of the elastic roller according to the present invention. FIG. 2 is a schematic explanatory view showing an image forming apparatus equipped with the fixing device according to the present invention. FIG. 3 is a schematic diagram illustrating an example of a pressing processing device for performing pressing processing by a traverse pressing roller. FIG. 4 is a schematic diagram illustrating an example of a press processing device for performing press processing by a plunge press roller. FIG. 5 is a schematic view showing a testing machine for carrying out the heating test of the elastic roller in the embodiment.

  The elastic roller according to the present invention comprises a foamed elastic layer formed on the outer peripheral surface of the shaft body and containing silicone rubber and 40 to 100 parts by mass of a silica-based filler with respect to 100 parts by mass of the silicone rubber. Be prepared. Therefore, the elastic roller according to the present invention only needs to include the shaft body and the foamed elastic layer, and may include other layers or films in addition to these.

  The elastic roller according to the present invention having the above configuration has an Asker C hardness of 35 to 55. If the Asker C hardness of the elastic roller is less than 35, for example, the nip pressure with the contacted body that contacts the elastic roller is insufficient, while if the Asker C hardness exceeds 55, the contact with the contacted body The nip width may be insufficient and the rotational torque may increase. That is, when this elastic roller has Asker C hardness in the above range, a large nip pressure and nip width can be ensured over a long period of time, for example, when mounted on a fixing device. The Asker C hardness of the elastic roller according to the present invention is preferably 35-50, and particularly preferably 40-45. Asker C hardness (1 kg load) can be measured in accordance with JIS K6253. For the Asker C hardness of the elastic roller according to the present invention, for example, the type of rubber, foaming agent and / or additive contained in the foamed silicone rubber composition forming the foamed elastic layer of the elastic roller is selected and / or It can be adjusted by changing the blending amount and the like, and by the molding conditions of the foamed elastic layer.

  The elastic roller according to the present invention has a thermal conductivity of 0.09 to 0.175 (W / m · k). When the elastic roller according to the present invention has a thermal conductivity in the above range, high heating efficiency can be exhibited. The thermal conductivity of the elastic roller according to the present invention is more preferably 0.12 to 0.16 (W / m · k), and 0.13 to 0.15 (W / m · k). Is particularly preferred. The thermal conductivity is measured using a thermal conductivity meter (trade name “Quick Thermal Conductivity Meter: QTM-500”, manufactured by Kyoto Electronics Industry Co., Ltd.), JIS R2251 Refractory Thermal Conductivity Test Method—Part 2 : According to the hot wire method (parallel method), a test piece (100 mm × 20 mm × 5 mm) having the same composition as the foamed elastic layer in the elastic roller according to the present invention was prepared in the same manner, and the test piece at 24 ° C. The thermal conductivity can be measured and determined as a value 60 seconds after the start of measurement. The thermal conductivity can be increased, for example, by changing the blending amount of the silica-based filler contained in the foamed silicone rubber composition forming the foamed elastic layer of the elastic roller, and by increasing or decreasing the foaming agent. It can be adjusted by changing.

  And, as described above, when the elastic roller according to the present invention has the Asker C hardness and thermal conductivity within the above range, the foamed elastic layer of the elastic roller according to the present invention includes a large amount of cells. When this elastic roller is heated to a predetermined surface temperature by heating from the outside, the heat hardly diffuses into the foamed elastic layer, stays on the surface, and exhibits high heating efficiency. As a result, the elastic roller according to the present invention can ensure a large nip pressure and nip width over a long period of time, although it can reach a predetermined surface temperature in a short time by external heating. That is, if the elastic roller according to the present invention has the Asker C hardness and the thermal conductivity within the above ranges, both durability and heat insulation can be achieved. As a result, the fixing device provided with the elastic roller according to the present invention can be activated quickly, and the preheating time can be greatly shortened.

  Further, when the surface of the elastic roller according to the present invention is heated to a predetermined surface temperature as described above, the foamed elastic layer of the elastic roller is excellent in heat insulation as described above. The heat applied to the surface of the elastic roller is difficult to diffuse inside the foamed elastic layer and remains on the surface. Therefore, when the image forming apparatus is on standby, the necessity to constantly heat or keep the elastic roller according to the present invention is not so high as that of the conventional fixing apparatus, and the amount of heating energy can be reduced. Therefore, the elastic roller according to the present invention is particularly preferably used as a fixing roller and / or a pressure roller heated from the outside.

  By the way, when a heater is housed in the elastic roller according to the present invention and the surface of the elastic roller according to the present invention is heated with this heater, the heat insulation of the foamed elastic layer is caused by the cells present in the foamed elastic layer. Since it is high, the surface of the elastic roller according to the present invention may not be promptly raised to a predetermined temperature. Therefore, the elastic roller according to the present invention has a surface temperature that is quickly raised to a predetermined temperature, and in order to achieve the purpose of holding the predetermined temperature for a long time, For example, the heat source is preferably stored in a fixing device including a heating unit that can be heated in a non-contact state.

  In particular, when the foamed elastic layer of the elastic roller according to the present invention is formed of a foamed silicone rubber composition containing silicone rubber, a specific amount of a silica-based filler, and a foaming agent, the foamed elastic layer will be described later. Thus, a large amount of cells can be included without damaging the cell structure containing the cells in the foamed elastic layer. Therefore, the foamed elastic layer in the elastic roller according to the present invention is preferably formed of a foamed silicone rubber composition described later.

  The elastic roller according to the present invention is adjusted to an arbitrary size according to a fixing device to be mounted. The elastic roller mounted on the fixing device is usually adjusted to an outer diameter of 30 to 40 mm. However, the elastic roller according to the present invention is excellent in durability and heat insulation. The outer diameter can be adjusted to, for example, 50 mm or more, which has been difficult until now, in order to ensure a large nip pressure and nip width.

  An elastic roller 1 as an embodiment of the elastic roller according to the present invention includes a shaft body 2 and a foamed elastic layer 3 formed on the outer peripheral surface of the shaft body 2 as 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 foamed elastic layer 3 is formed on the outer peripheral surface of the shaft body 2. The foamed elastic layer 3 contains silicone rubber and 40 to 100 parts by mass of a silica-based filler with respect to 100 parts by mass of the silicone rubber. The silicone rubber is basically the same as the silicone rubber (or a crosslinked cured product thereof) contained in the foamed silicone rubber composition described later. The silica-based filler is basically the same as the silica-based filler contained in the foamed silicone rubber composition described later. Content of the silica type filler in the foamed elastic layer 3 is 40 to 100 parts by mass with respect to 100 parts by mass of the silicone rubber. When the content of the silica-based filler is within the above range, the Asker C hardness of the foamed elastic layer 3 does not decrease more than necessary even if a large amount of cells are formed in the foamed elastic layer 3 in order to enhance the heat insulation. Since damage to the foamed elastic layer 3 can be prevented over a long period of time, the foamed elastic layer 3 can achieve both high heat insulation and durability. The content of the silica-based filler in the foamed elastic layer 3 is preferably 45 to 70 parts by mass with respect to 100 parts by mass of the silicone rubber in that both higher heat insulation and durability can be achieved. 50 to 60 parts by mass is particularly preferable. The foamed elastic layer 3 may contain various additives contained in the foamed silicone rubber composition or composites thereof in addition to the silicone rubber and the silica-based filler.

  The foamed elastic layer 3 is a foamed elastic layer having cells on its inner and / or outer surface (cells opened on the outer peripheral surface and end surface of the foamed elastic layer 3 are not shown in FIG. 1). If the foamed elastic layer 3 has cells, the hardness of the foamed elastic layer 3 can be reduced, while the heat insulating property of the foamed elastic layer 3 can be improved. Here, the cell which the foaming elastic layer 3 has refers to the hollow area | region produced by foaming or decomposition | disassembly of the foaming agent contained in a foaming silicone rubber composition. The plurality of cells in the foamed elastic layer 3 are in a state where they do not contact or communicate with other cells (referred to as independent cell states), a state where they contact or communicate with other cells (communication cell state) Or the independent cell state and the communication cell state may coexist.

  Such a foamed elastic layer 3 preferably has a hardness such that the elastic roller 1 has an Asker C hardness in the above range. In this example, since the foamed elastic layer 3 is the outermost layer of the elastic roller 1, the foamed elastic layer 3 usually has the same Asker C hardness as the Asker C hardness of the elastic roller 1.

  In the foamed elastic layer 3, the average cell diameter of the cells formed in the foamed elastic layer 3, the foaming magnification of the foamed elastic layer 3 and the like are adjusted, so that the effect of the present invention can be further enhanced. preferable. For example, the average cell diameter of the foamed elastic layer 3 is preferably 60 to 800 μm, particularly preferably 100 to 400 μm, and the foaming ratio of the foamed elastic layer 3 is preferably 180 to 420%. 200 to 350% is particularly preferred. When the expansion ratio of the foamed elastic layer 3 is within the above range, a large amount of cells can be formed in the foamed elastic layer 3 having Asker C hardness within the above range by the specific amount of silica-based filler.

In the foamed elastic layer 3, the expansion ratio and the average cell diameter are adjusted by the curing conditions of the foaming agent or the foamed silicone rubber composition contained in the foamed silicone rubber composition to be described later that forms the foamed elastic layer 3. Can do. The expansion ratio can be calculated from the volume and mass of the foamed elastic layer 3 measured by a conventional method. In addition, the average cell diameter of the cells is determined by observing a region of about 20 mm ² with an electron microscope or the like on the surface of the foamed elastic layer 3 or a cut surface obtained by cutting an arbitrary surface. The maximum length of the opening is measured, and the measured maximum length can be obtained as an average length obtained by arithmetic averaging.

  The foamed elastic layer 3 preferably has a thermal conductivity such that the elastic roller 1 has a thermal conductivity in the above range. In this example, since the foamed elastic layer 3 is the outermost layer of the elastic roller 1, the foamed elastic layer 3 usually has the same thermal conductivity as that of the elastic roller 1.

The density of the foamed elastic layer 3 is preferably 0.395~0.7 (g / cm ^3), particularly preferably from 0.42~0.6 (g / cm ^3). When the density is within the above range, the effect of the present invention can be further enhanced. The density of the foamed elastic layer 3 can be measured by an electron density meter (in-water displacement method, water temperature 23 ° C.).

  The form of the foamed elastic layer 3 is not particularly limited. For example, the foamed elastic layer 3 may have a so-called straight shape that is adjusted to have a uniform outer diameter over the axial direction, and the outer diameter at the center portion is at the both end portions. It may be a so-called crown shape that is adjusted to be larger than the outer diameter, and further, it is a so-called reverse crown shape that is adjusted so that the outer diameter at the center is smaller than the outer diameter at both ends. Also good. In this example, the foamed elastic layer 3 is formed in the straight shape as shown in FIG.

  The thickness of the foamed elastic layer 3 is not particularly limited and can usually be adjusted to 2 to 20 mm. Since this elastic roller 1 is excellent in durability and heat insulating properties, the thickness of the foamed elastic layer 3 should be adjusted to a thickness that has been difficult until now in order to ensure a large nip pressure and nip width. For example, it can be adjusted to 15 mm or more. In the present invention, the thickness of the foamed elastic layer 3 is particularly preferably adjusted to 3 to 12 mm.

  The foamed silicone rubber composition forming the foamed elastic layer 3 contains a silicone rubber, a foaming agent, a specific amount of silica-based filler, and various additives as required. As such a foamed silicone rubber composition, for example, an addition reaction type foamed silicone rubber composition can be preferably exemplified.

  The addition reaction type foamed silicone rubber composition contains a vinyl group-containing silicone raw rubber, a specific amount of a silica-based filler, a foaming agent, an addition reaction crosslinking agent, an addition reaction catalyst, and a reaction control agent, If desired, an organic peroxide crosslinking agent, a heat resistance improver, and various additives may be further contained.

  Examples of the vinyl group-containing silicone raw rubber include millable silicone rubber and heat-crosslinked silicone rubber (HTV: High Temperature Vulcanizing). These vinyl group-containing silicone raw rubbers have the property that a foaming agent and an addition reaction cross-linking agent can be easily kneaded with a roll mill or the like in a later step, and are used alone or in combination of two or more. Can be used. Examples of the vinyl group-containing silicone raw rubber include trade name “KE-77VBS” manufactured by Shin-Etsu Chemical Co., Ltd.

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. . Examples of the silane coupling agent represented by the above general formula include trade names “KBM1003” and “KBE402” manufactured by Shin-Etsu Chemical Co., Ltd., and trade names “Celite Super Floss” manufactured by Toshin Kasei Co., Ltd. It can be easily obtained. 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 quantity of a silica type filler is 40-100 mass parts with respect to 100 mass parts of said vinyl group containing silicone raw rubbers, It is preferable that it is 45-70 mass parts, and it is 50-60 mass parts. Particularly preferred. A silica type filler can be used individually by 1 type or in mixture of 2 or more types.

  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, azonitrile 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 present invention, the foaming agent is preferably an organic foaming agent because the foamed elastic layer 3 can be easily formed. Specifically, for example, azodicarboxylic acid amide, azobis-iso An azo compound such as butyronitrile is preferably used. In particular, dimethyl-1,1'-azobis (1-cyclohexanecarboxylate) can be preferably used. The blending amount of the foaming agent may be, for example, 0.1 to 10 parts by mass, particularly 0.5 to 5 parts by mass with respect to 100 parts by mass of the vinyl group-containing silicone raw rubber. A foaming agent can be used individually by 1 type or in mixture of 2 or more types.

  Suitable examples of the addition reaction crosslinking agent include known organohydrogenpolysiloxanes as addition reaction type crosslinking agents having two or more SiH groups (SiH bonds) in one molecule. The addition amount of the addition reaction crosslinking agent is preferably 0.01 to 20 parts by mass with respect to 100 parts by mass of the vinyl group-containing silicone raw rubber. An addition reaction crosslinking agent can be used individually by 1 type or in mixture of 2 or more types.

  The addition reaction catalyst may be any catalyst that is usually used in addition reactions of silicone raw rubber, and examples thereof include simple metals of Group 9 or 10 of the periodic table and compounds thereof. The addition amount of the addition reaction catalyst is sufficient as the catalyst amount, and is usually 1 to 1 with respect to the addition reaction type foamed silicone rubber composition in terms of the metal amount of Group 9 or Group 10 of the periodic table. 000 ppm. An addition reaction catalyst can be used individually by 1 type or in mixture of 2 or more types.

  As the reaction control agent, a known reaction control agent can be used without particular 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 reaction control agents can be used alone or in combination of two or more.

  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. An organic peroxide crosslinking agent can be used individually by 1 type or in mixture of 2 or more types.

  The heat resistance improver may be any compound that improves the heat resistance of the foamed elastic layer 3, and examples thereof include carbon black, iron oxide (also referred to as bengara), cerium oxide, and cerium hydroxide. These can be used individually by 1 type or in mixture of 2 or more types.

  The various additives can be used singly or in combination of two or more without particularly limiting the additives such as conductivity imparting agents such as carbon black.

  As the foamed silicone rubber composition containing the vinyl group-containing silicone raw rubber, the silica-based 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. Can be obtained. In particular, examples of the foamed silicone rubber composition containing a silica-based filler in the above range include trade names “KE-151KU”, “KE-9510U”, and “KE-981U” manufactured by Shin-Etsu Chemical Co., Ltd. It is done.

  As described above, according to the foamed silicone rubber composition containing the silicone rubber, the foaming agent, and the specific amount of the silica-based filler, the foamed elastic layer 3 having the above characteristics can be formed. In the invention, in order to adjust Asker C hardness and / or thermal conductivity, the foamed elastic layer 3 and the foamed silicone rubber composition do not need to contain a hollow body instead of a cell, for example, an inorganic microhollow body. Good.

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

  The elastic roller according to the present invention is produced by a manufacturing method including a step of forming a foamed elastic layer 3 by foaming and curing a foamed silicone rubber composition containing a silicone rubber, a foaming agent, and a specific amount of silica-based filler. Can be manufactured.

  In this manufacturing method, first, the shaft body 2 is prepared. The shaft body 2 is made of, for example, a metal such as iron, aluminum, stainless steel, brass or an alloy thereof, a resin such as a thermoplastic resin or a thermosetting resin, and carbon black or metal powder as a conductivity-imparting agent for the resin. It is prepared in a desired shape by a known method using a material such as a conductive resin blended with a body. When the shaft body 2 is required to have conductivity, in addition to the metal and the conductive resin, the surface of the insulating core body formed of the resin or the like is plated by a regular method to thereby form the shaft body 2. Can be formed. Among the above materials, a metal is preferable and aluminum or stainless steel is particularly preferable from the viewpoint that conductivity can be easily imparted. The shaft body 2 may be coated with a primer layer on the outer peripheral surface as desired.

  In this production method, a foamed silicone rubber composition, preferably a foamed silicone rubber composition containing an organic foaming agent, is then continuously formed by extrusion molding on the outer peripheral surface of the shaft body 2 thus produced. Then, heat molding is performed by pressing, injection molding, or the like. In the thermoforming of the foamed silicone rubber composition, first, a foamed silicone rubber composition that forms the foamed elastic layer 3 is disposed on the outer peripheral surface of the shaft body 2 on which an adhesive layer or a primer layer is optionally formed. As a method of disposing the foamed silicone rubber composition on the outer peripheral surface of the shaft body 2, for example, the shaft body 2 and the foamed silicone rubber composition are integrally extracted by an extruder or the like and foamed on the outer peripheral surface of the shaft body 2. Examples thereof include a method of arranging the silicone rubber composition, and a method of injecting the foamed silicone rubber composition into a mold for housing the shaft body 2 and disposing the foamed silicone rubber composition on the outer peripheral surface of the shaft body 2. . Among these, the method of dispensing the shaft body 2 and the foamed silicone rubber composition integrally with an extruder or the like is preferable because the operation is easy and can be performed continuously.

  In this manufacturing method, after the foamed silicone rubber composition is disposed on the outer peripheral surface of the shaft body 2 in this manner, the foamed silicone rubber composition is heated together with the shaft body 2. The foamed silicone rubber composition may be heated under conditions sufficient for the rubber contained in the foamed silicone rubber composition, for example, vinyl group-containing silicone raw rubber to crosslink and the foaming agent to decompose or foam. For example, the foamed silicone rubber composition is usually heated to about 170 to 500 ° C., particularly 200 to 400 ° C. by a heating furnace such as an infrared heating furnace or a hot air furnace, a heating machine such as a dryer, etc. Heat for less than an hour, especially 5-30 minutes. In this way, when the foamed silicone rubber composition is heated, the foamed material is foamed, and the silicone rubber is crosslinked to form a cured rubber body containing cells. This rubber cured body may be further subjected to secondary heating as desired. The secondary heating is a step of more reliably curing the rubber cured body heated under the above conditions, and the effect of stabilizing the physical properties of the rubber cured body obtained by curing the foamed silicone rubber composition by the secondary heating. can get. In the secondary heating, for example, the rubber cured body heated under the above-described conditions is heated at 180 to 250 ° C., preferably 190 to 230 ° C., for 1 to 24 hours, preferably 3 to 10 hours, or the mold is removed. For example, it is carried out by heating again at 130 to 200 ° C., preferably 150 to 180 ° C. for 5 minutes to 24 hours, preferably 10 minutes to 10 hours.

  In this manufacturing method, as one of the methods for easily forming the elastic roller having the above characteristics, there is a method of pressing the cured rubber body formed in this way. When the rubber cured body is pressed, the resulting elastic roller has the above-described characteristics and can achieve both durability and heat insulation. The pressing process may be any method that presses the surface of the cured rubber body 5 under a predetermined condition. Examples thereof include a pressing process using a traverse pressing roller and a pressing process using a plunge pressing roller.

<Pressing process with traverse pressing roller>
In this pressing method, a pressing processing device 80 shown in FIG. 3 is used. As shown in FIG. 3, the pressing device 80 is a fixing means 82 for fixing the cured rubber body 5 around the central axis of the shaft body 2, for example, the shaft body 2 is sandwiched and fixed from both ends. Rotating means 83, for example, a motor and the rubber cured body 5, which are connected to the pair of clamping members and the fixing means 82, rotate the rubber cured body 5 about the central axis of the shaft body 2 via the fixing means 82. The traverse pressing roller 84 to be pressed and the traverse pressing roller 84 are moved relatively in the axial direction of the rubber cured body 5, and the traverse pressing roller 84 is moved in the center direction of the rubber cured body 5 to press against the rubber cured body 5. A movement adjusting means 85 for adjusting the amount d, and a pressing roller support jig 86 that rotatably supports the traverse pressing roller 84 and is mounted on the movement adjusting means 85 are provided. Here, the traverse pressing roller 84 includes a shaft body and a cylindrical body formed on the outer peripheral surface thereof.

  The dimensions and materials of the shaft body in the traverse press roller 84 are not particularly limited. For example, the outer diameter of the shaft body in the traverse press roller 84 shown in FIG. 3 is adjusted to 8 to 15 mm. 1 is made of the same material as the shaft body 2. Further, the dimensions and materials of the cylindrical body in the traverse pressing roller 84 are not particularly limited. For example, the cylindrical body in the traverse pressing roller 84 shown in FIG. 3 has an outer diameter of 15 to 100 mm and an axial length. It is adjusted to 10-200 mm. The cylindrical body is formed of various resins, various metals, and the like, and is in pressure contact with the rubber cured body 5. It is important that the cylindrical body in the traverse pressing roller 84 has a specific hardness in order to form the desired foamed elastic layer 3. In the traverse pressing roller 84 in the press processing device 80, the hardness of the cylindrical body is What is necessary is just to be adjusted to the hardness larger than the rubber cured body 5, for example, it is preferable that it is 33-43 in HRC hardness.

  In order to press the cured rubber body 5 using the pressing device 80, first, the cured rubber body 5 manufactured as described above is clamped from both ends of the shaft body 2 and fixed to a set of fixing means 82. To do. Next, as shown in FIG. 3, the movement adjusting means 85 is operated to move the traverse pressing roller 84 in the vicinity of one end of the cured rubber body 5 and move the traverse pressing roller 84 toward the center of the cured rubber body 5. The amount of pressing d against the cured rubber body 5, that is, the amount by which the cured rubber body 5 is pushed by the traverse pressing roller 84 becomes a predetermined value d, for example, 1 to 20 mm, preferably 2 to 15 mm. As described above, the position of the traverse pressing roller 84 is adjusted as appropriate.

  Next, the rotating means 83 is activated to rotate the cured rubber body 5 fixed to the fixing means 82 around the central axis of the shaft body 2. The rotational speed of the rubber cured body 5 at this time is preferably adjusted to 5 to 1500 rpm / min, particularly preferably 10 to 1000 rpm / min, in that a desired foamed elastic layer 3 can be formed. When the rubber cured body 5 is rotated, the traverse pressing roller 84 pressing the rubber cured body 5 rotates together with the rubber cured body 5. While maintaining this state, the movement adjusting means 85 is activated, and the traverse pressing roller 84 is moved in one direction (the direction of the arrow shown in FIG. 3) from one end of the rubber cured body 5 to the other end. Move. At this time, the moving speed of the pressing roller 13 is preferably adjusted to 20 to 1200 mm / min, particularly preferably 50 to 900 mm / min, in that the desired foamed elastic layer 3 can be formed. In this pressing method, in addition to the movement of the traverse pressing roller 84 in the one direction, the traverse pressing roller 84 may be moved in the reverse direction from the other end to the one end. The movement of the traverse pressing roller 84 may be performed for a plurality of cycles, with the movement of the pressing roller 84 in the one direction and the movement in the opposite direction as one cycle. In this way, the rubber cured body 5 can be pressed. In the method using the pressing device 80, the physical properties and the like of the foamed elastic layer 3 can be appropriately adjusted according to the rotation speed of the rubber cured body 5, the number of movements of the traverse pressing roller 84, and the pressing amount d. . The press processing device 80 is equipped with one traverse pressing roller 84. The press processing device 80, for example, faces the rubber cured body 5 fixed to the fixing means 82, and the rubber processing body 5 A plurality (for example, 2, 3, or 4 or more) of traverse pressing rollers 84 may be provided at equal intervals in the outer circumferential direction.

<Pressing process with plunge pressing roller>
For this pressing method, a pressing processing device 81 shown in FIG. 4 is used. The press processing device 81 shown in FIG. 4 includes a plunge press roller 87 and a press roller support jig 88 in place of the traverse press roller 84, the movement adjusting means 85, and the press roller support jig 86. The press processing device 81 is basically configured in the same manner. The plunge pressing roller 87 includes a shaft body and a cylindrical body formed on the outer peripheral surface thereof, and preferably the length in the axial direction is set longer than the length in the axial direction of the rubber cured body 5. Is basically the same as the traverse pressing roller 84. The cylindrical body of the plunge pressing roller 87 is preferably adjusted to have an axial length of 200 to 350 mm. The treatment using the pressure processing device 81 is performed by the cured rubber body without moving the plunge pressing roller 87 while maintaining the state of being pressed over the axial direction of the cured rubber body 5 so as to be the pressing amount d by the plunge pressing roller 87. The process is basically performed in the same manner as the process using the press processing device 80 except that 5 is rotated for a predetermined time. And in the method using this press processing apparatus 81, each physical property etc. of the foaming elastic layer 3 are suitably adjusted with the above-mentioned rotation speed and rotation time of the rubber cured body 5, and the pressing amount d of the plunge pressing roller 87. Can do. The pressure processing device 81 is equipped with a single plunge pressing roller 87. For example, the pressure processing device 81 is opposed to the rubber cured body 5 fixed to the fixing means 82, so that the rubber cured body 5 Plural (for example, two, three, or four or more) plunge pressing rollers 87 may be provided at equal intervals in the outer circumferential direction.

  In addition to or instead of the pressing process, for example, a local pressing process by the traverse pressing roller 84, a pressing process by a pitching machine method, or the like can be employed.

  The pressing treatment is preferably performed under a condition that the Asker C hardness of the rubber cured body 5 is reduced by 2 to 15, and is particularly preferably executed under a condition that the Asker C hardness is reduced by 5 to 10. When the rubber cured body 5 is pressed under such conditions, in addition to being able to achieve both a high level of durability and heat insulating properties when used as an elastic roller, the hardness is drastically reduced, corresponding to 8 hours of continuous use from the beginning of printing. The rate of decrease in hardness can be reduced, and the durability can be further improved, and the fluctuation rate of the nip width can also be reduced. The conditions under which the Asker C hardness decreases by the above range are appropriately selected from the above conditions, for example, depending on the foaming magnification, thickness, etc. of the rubber cured body 5. Therefore, when the rubber cured body 5 is subjected to a pressing treatment, the foamed silicone rubber composition in which the Asker C hardness of the rubber cured body 5 is increased in advance so that the Asker C hardness of the manufactured elastic roller is within the above range. Goods should be used.

  In this manufacturing method, the rubber cured body thus molded is subjected to a grinding step, a polishing step, a cutting step, and the like according to the shape required for the foamed elastic layer 3 before or after the pressing treatment. Is given. For example, when the foamed elastic layer 3 is formed in a straight shape, the rubber cured body is subjected to a grinding process or the like so that the outer diameter from one end of the foamed elastic layer 3 to the other end is uniform. Is done. The grinding process, the polishing process, and / or the cutting process can be performed according to a conventional method using a conventionally used grinder, cylindrical grinder, file, or the like. In addition, after the grinding process, the polishing process and / or the cutting process, the foamed elastic layer 3 subjected to these processes 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.

  In this manner, an elastic roller having Asker C hardness and thermal conductivity in the above ranges can be manufactured.

  Since the elastic roller according to the present invention has the above characteristics and effects, it is preferably used as a fixing roller and / or a pressure roller mounted on a fixing device provided in the image forming apparatus. In particular, the elastic roller according to the present invention has the above characteristics and effects, so that the fixing roller and / or the pressure roller is mounted on a fixing device configured to heat the fixing roller and / or the pressure roller from the outside in a non-contact state. It is suitably used as a roller and / or a pressure roller. The elastic roller according to the present invention is suitable as a fixing roller and / or a pressure roller to be mounted on a fixing device provided in an image forming apparatus with high definition and high speed because of the above characteristics and effects. Used.

  The elastic roller according to the present invention is not limited to the above-described embodiments, and various modifications can be made within a range in which the object of the present invention can be achieved. For example, the foamed elastic layer 3 has a single layer structure, but may have a multilayer structure of two or more layers in the present invention.

  The elastic roller 1 includes a shaft body 2 and a foamed elastic layer 3. The elastic roller according to the present invention includes a shaft body, a foamed elastic layer formed on the outer peripheral surface thereof, and a foamed elastic layer. And a tube layer formed on the outer peripheral surface. When the tube layer is formed on the outer surface of the foamed elastic layer, the releasability of the developer can be improved. The tube layer may have a single layer structure or a stacked structure in which two or more layers are stacked. The tube layer is formed to a thickness of 1 to 100 μm, for example. The material for forming the tube layer is not particularly limited. However, the elastic roller 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, phenol Modified alkyd resin such as 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. The tube layer may be a metal sleeve, and examples of the metal forming the sleeve include a metal material having high thermal conductivity such as iron, stainless steel, and nickel.

  In order to form the tube layer, in the manufacturing method, the foamed elastic layer is inserted into a tubular body previously formed in a cylindrical shape having the same inner diameter as the outer diameter of the foamed elastic layer. It can be formed on the outer surface. When the tube layer is formed in this way, the tube layer having a smooth surface can be formed without being greatly influenced by the uneven shape present on the surface of the foamed elastic layer. The tube layer may be formed by applying the material to the outer peripheral surface of the foamed elastic layer according to, for example, a dip method or a spray method, and then curing and / or crosslinking.

  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. 2, an 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 periphery of the image carrier 31. A charging unit 32 such as a charging roller, an exposure unit 33, a developing unit 40, a transfer unit 34 such as a transfer roller and a cleaning unit 37, and a fixing unit 35 are provided on the downstream side in the conveyance direction of the recording medium. The developing means 40 is formed basically in the same manner as the conventional developing means. Specifically, as shown in FIG. 3, the developer 42 is supplied to the developer accommodating portion 41 and the image carrier 31. A developer carrier 44, a developer supply unit 43 that supplies the developer 42 to the developer carrier 44, and a developer regulating member 45 that charges the developer 42 are provided.

  The fixing unit 35 is a fixing device including a heating unit 57 and an endless belt 55. That is, the fixing device 35 has a fixing roller 53 and an endless arrangement disposed in the vicinity of the fixing roller 53 in a casing 50 having an opening 52 through which the recording medium 36 passes, as shown in a cross section in FIG. A belt support roller 54, an endless belt 55 wound around the fixing roller 53 and the endless belt support roller 54, a pressure roller 56 that presses the fixing roller 53 via the endless belt 55, and a contactless contact with the endless belt 55. And a heating means 57 that heats the fixing roller 53 from the outside via the endless belt 55, and the fixing roller 53 and the pressure roller 56 are in contact with or pressed against each other via the endless belt 55. Thus, the pressure heat fixing device is rotatably supported. 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. The fixing roller 53 and the pressure roller 56 are in pressure contact with the fixing roller 53 via an endless belt 55 by an urging means (not shown) such as a spring. In the fixing device 35, the elastic roller according to the present invention is mounted as at least one of the fixing roller 53 and the pressure roller 56. The heating means 57 employs a radiant heating method using a halogen heater, a reflector, or the like, a direct contact heating method in which a heater or the like is directly contacted to heat, an induction heating method, or the like. The heating means 57 is a member having a length substantially the same as the length of the fixing roller 53 in the axial direction, and may be disposed in any of the fixing devices 35. However, as shown in FIG. It is preferable that the fixing roller 53 is arranged substantially in parallel with a certain distance from the surface. In the induction heating method, a heating coil is used, and this heating coil is usually a ferromagnetic material such as ferrite, and is a typical shape used for a switching power source. It is formed into a mold or the like, and is formed by winding a conducting wire. By passing the recording medium 36 between the endless belt 55 and the pressure roller 56, the recording medium 36 is heated simultaneously with the pressurization, and the developer 42 (electrostatic latent image) transferred to the recording medium 36 is fixed. be able to.

  The image forming apparatus 30 according to the present invention operates as follows. First, in the image forming apparatus 30, the image carrier 31 is uniformly charged by the charging unit 32, and an electrostatic latent image is formed on the surface of the image carrier 31 by the exposure unit 33. Next, the developer 42 is supplied from the developing unit 40 to the image carrier 31 to develop the electrostatic latent image, and the developer image is conveyed between the image carrier 31 and the transfer unit 34 on the recording member 36. Is transcribed. The recording body 36 is conveyed to the fixing unit 35, and the developer image is fixed on the recording body 36 as a permanent image. In this way, an image can be formed on the recording body 36.

  In the fixing device 35 and the image forming apparatus 30 according to the present invention, the elastic roller according to the present invention is employed as at least one of the fixing roller 53 and the pressure roller 56. It can be fixed on a recording medium.

  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 may be, for example, an electrostatic image forming apparatus. Good. 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. .

Example 1
A shaft body (diameter 15 mm × length 370 mm, SUM22) subjected to electroless nickel plating was washed with toluene, and a primer “No. 101A / B” (manufactured by Shin-Etsu Chemical Co., Ltd .: trade name) was applied. The primer-treated shaft body was baked 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.

  Next, the surface-treated silica “Celite Super Floss” (manufactured by Toshin Kasei Co., Ltd .: trade name) is applied to 100 parts by mass of the silicone raw rubber “KE-77VBS” (trade name: Shin-Etsu Chemical Co., Ltd.). A silicone rubber compound was prepared by blending parts by mass. 100 parts by mass of the prepared silicone rubber compound, 2.0 parts by mass of an addition reaction crosslinking agent “C-153A” (manufactured by Shin-Etsu Chemical Co., Ltd .: trade name), an appropriate amount of platinum catalyst as an addition reaction catalyst, and a reaction control agent 0.5 parts by mass of “R-153A” (manufactured by Shin-Etsu Chemical Co., Ltd .: trade name), 3 parts by mass of organic peroxide crosslinking agent “C-3” (manufactured by Shin-Etsu Chemical Co., Ltd .: trade name), Appropriate amount of heat resistance improver “KEP-12” (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.) and organic foaming agent azobis-isobutyronitrile “KEP-13” (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.) 2.0 parts by mass were sufficiently kneaded with two rolls to prepare an addition reaction type foamed silicone rubber composition A.

  Next, the shaft body 2 on which the primer layer is formed and the addition reaction type foamed silicone rubber composition A are integrally dispensed by an extrusion molding machine, and then the addition reaction type foaming is performed using an infrared heating furnace (IR furnace). The silicone rubber composition A was heated at 250 ° C. for 10 minutes to foam-crosslink the addition reaction type foamed silicone rubber composition A. Thereafter, the addition reaction type foamed silicone rubber composition A after foaming and crosslinking is secondarily heated at 200 ° C. for 7 hours using a gear oven and left at room temperature for 1 hour or more. It was ground to an outer diameter of 35 mm.

  Next, this rubber cured body 5 was subjected to the pressing method 1 “pressing process using a traverse pressing roller” under the following conditions using a pressing apparatus 80 shown in FIG. 3. The traverse pressing roller 84 in the pressing device 80 was provided with an iron (S45C) cylindrical body having an outer diameter of 50 mm and an axial length of 50 mm on the outer peripheral surface of a metal shaft having an outer diameter of 15 mm. The hardness of the cylindrical body was larger than that of the rubber cured body (specifically, the hardness was within a range of 33 to 43 in terms of HRC hardness). After adjusting the pressing amount d of the traverse pressing roller 84 against the rubber cured body 5 to 5 mm, the traverse pressing roller 84 is rotated on one side of the rubber cured body 5 while the rubber cured body 5 is rotated at a rotational speed of 200 rpm / min. It was moved from one end to the other end in one direction (in the direction of the arrow shown in the figure) at a moving speed of 150 mm / min. Next, under the same conditions, the traverse pressing roller 84 was moved in the reverse direction from the other end of the rubber cured body 5 to the one end. Thus, the elastic roller of Example 1 provided with the foaming elastic layer 3 with an outer diameter of 35 mm was produced.

(Examples 2 and 3)
Each elastic roller was manufactured in the same manner as in Example 1 except that the compounding amount of the silica in the silicone rubber compound was changed to 45 parts by mass (Example 2) or 95 parts by mass (Example 3).
(Examples 4 and 5)
3.0 parts by mass (Example 4) or 1.0 part by mass of 2.0 parts by mass of the organic foaming agent azobis-isobutyronitrile “KEP-13” (manufactured by Shin-Etsu Chemical Co., Ltd .: trade name) Except for changing to Example 5), each elastic roller was manufactured in the same manner as in Example 1.

(Comparative Example 1)
An elastic roller was produced in the same manner as in Example 1 except that the amount of the silica in the silicone rubber compound was changed to 30 parts by mass.
(Comparative Example 2)
The addition reaction type foamed silicone rubber composition was foam-crosslinked in the same manner as in Example 1 by changing the amount of the silica in the silicone rubber compound to 105 parts by mass. However, this composition could not be molded and was elastic. Roller could not be manufactured.

  The Asker C hardness (1 kg load) of the rubber cured body 5 in Examples 1 to 5 and Comparative Example 1, and the Asker C hardness (1 kg load) of each elastic roller of Examples 1 to 5 and Comparative Example 1 manufactured as described above. The results measured according to the method are shown in Table 1. Moreover, the result of having measured the foaming magnification of each formed elastic foam layer 3, the average cell diameter, and the density according to the said method is shown in Table 1. Each addition reaction type foamed silicone rubber composition prepared for forming the foamed elastic layer in the elastic roller of each example and comparative example was molded into a size of 150 mm × 500 mm × 10 mm with two rolls and 10 ° C. at 250 ° C. After heating for minutes, secondary vulcanization was performed at 200 ° C. for 7 hours to produce a foam sheet. The skin layer surface of the surface of the foam sheet is removed with a slicer, cut into a predetermined size (100 mm × 20 mm × 5 mm) to obtain a test piece, and the thermal conductivity measured according to the method described above for each of the elastic rollers of each of the examples and comparative examples. It was set as thermal conductivity. The results are shown in Table 1.

(Heating test)
The heating efficiency of the elastic rollers of Examples 1 to 5 and Comparative Example 1 was evaluated by the surface temperature of the elastic roller after 10 minutes of press contact using the following tester 70. As shown in FIG. 5, the testing machine 70 is fixed to the lower surface inside the housing and is provided on both sides of the heating roller 71 provided with an internal heater 72 along the axial direction of the heating roller 71. A test roller mounting part 74 provided on the upper surface inside the housing so as to be movable up and down so as to face the heat insulating material 73 and the heating roller 71, and a pressing force adjusting means capable of moving the test roller mounting part 74 up and down. 75, for example, a pressure adjusting micrometer. The heating roller 71 includes a metal (stainless steel, SUS304) roller having a diameter of 20 mm. The elastic rollers of Examples 1 to 5 and Comparative Example 1 were mounted on the bearings of the test roller mounting portion 74, the heat insulating material 73 and the internal heater 72 were activated, and the surface temperature of the heating roller 71 was adjusted to 200 ° C. After the surface temperature of the heating roller 71 reaches 200 ° C., the elastic roller 76 is pressed against the heating roller 71 so as to have a nip width of 2 mm in the circumferential direction, and the heating roller 71 is rotated at a rotational speed of 130 rpm. The surface temperature of the elastic roller 76 was measured with an infrared thermometer every 10 minutes until 10 minutes later. The results are shown in Table 1. If the surface temperature 10 minutes after the press contact is 180 ° C. or higher, the heating efficiency is higher than that of a fixing roller mounted on a conventional fixing device, and there is no practical inconvenience due to the low heating efficiency.

  As shown in Table 1, the elastic rollers of Examples 1 to 5 all had an Asker C hardness of 35 to 55. As a result, since these elastic rollers can ensure a large nip pressure and nip width over a long period of time when they are mounted on a fixing device, it can be sufficiently estimated that the initial functions such as developer fixing ability can be exhibited over a long period of time. .

DESCRIPTION OF SYMBOLS 1,76 Elastic roller 2 Shaft body 3 Foam elastic layer 5 Heat-hardening body 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 storage Unit 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 57 Heating means 70 Durability test device 71 Heating roller 72 Internal heater 73 External heater 74 Test roller mounting portion 75 Pressing force adjusting means 80, 81 Press processing device 82 Fixing means 83 Rotating means 84 Traverse pressing roller 85 Movement adjusting means 86, 88 Pressing roller support jig 87 Plunge pressing roller

Claims (2)

It is formed on the outer peripheral surface of the shaft body, and comprises a foamed elastic layer containing silicone rubber and 40 to 100 parts by mass of a silica-based filler with respect to 100 parts by mass of the silicone rubber,
The foamed elastic layer is formed by pressing a cured rubber formed by foaming and curing a foamed silicone rubber composition containing silicone rubber and a silica-based filler, and the Asker C hardness of the foamed elastic layer. Is smaller than Asker C hardness of the rubber cured body, is 35 to 55, and has a thermal conductivity of 0.09 to 0.175 (W / m · k). A fixing roller, an endless belt wound around the fixing roller, a pressure roller pressed against the fixing roller via the endless belt, and a non-contacting arrangement with the endless belt, A fixing device comprising heating means for heating,
The fixing device according to claim 1, wherein at least one of the fixing roller and the pressure roller is an elastic roller according to claim 1.

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