JP2008003480A - Elastic roller, fixing device for image forming apparatus and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an elastic roller capable of forming a high-quality image and also contributing to the improvement of the durability of an image forming apparatus, and contributing to the simplification of structure because it need not be constituted as complicated laminated or multilayered constitution; a fixing device for an image forming apparatus capable of forming a high-quality image and also contributing to the improvement of the durability of an image forming apparatus; and the image forming apparatus capable of forming a high-quality image and excellent in durability. <P>SOLUTION: The elastic roller 1 has a shaft body 2 and an elastic layer 3 provided on the outer periphery of the shaft body 2, and is set so that the rate of the diameter of the shaft body to the outside diameter of the elastic layer may be 25-60%. The fixing device for the image forming apparatus and the image forming apparatus are quipped with the elastic roller 1. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an elastic roller, a fixing device for an image forming apparatus, and an image forming apparatus. More specifically, the present invention can be used in, for example, an image forming apparatus and contributes to higher definition of an image and improved durability of the image forming apparatus. The present invention relates to an elastic roller, a fixing device for an image forming apparatus provided with such an elastic roller, and an image forming apparatus provided with 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.

  Among the various rollers, Patent Document 1 discloses a pressurizing roller that is configured by sequentially laminating a silicone rubber layer, a silicone sponge layer, and a fluororesin tube layer sequentially from the central core to the surface layer. The feature is that the thickness ratio of the silicone rubber layer and the silicone sponge layer is in the range of 2: 1 to 7: 1 ”. In this Patent Document 1, it is asserted that by using the pressure roller having the above-described configuration, “all problems such as paper wrinkles, toner releasability, and shortening of warm-up time can be solved”. (See paragraph number 0040 of Patent Document 1). Further, in Patent Document 2, as a fixing roller, “a rubber layer having a thickness of 0.15 to 0.4 mm and a rubber hardness of 1 to 45 ° is formed on a core metal having a thickness of 0.5 to 2.5 mm, There has been proposed a “fixing roller” in which a thin layer of a fluororesin tube having a thickness of 20 to 50 μm is formed thereon. In Patent Document 2, it is asserted that “a roller having excellent fixing properties and excellent durability can be obtained, and as a result, a fixing device having excellent cost performance” can be obtained. (See paragraph number 0037 of Patent Document 2).

The microfilm of Japanese Utility Model Application No. 4-3871 (Japanese Utility Model Publication No. 5-59474) JP-A-10-254278

  Incidentally, the elastic roller provided in the image forming apparatus is in contact with another rotating member such as a pressure roller. When the elastic roller contacts another rotating member, the peripheral surface of the elastic roller and the peripheral surface of the rotating member are not in line contact with the axis, but the peripheral surface of the elastic roller is the peripheral surface of the rotating member. As a result, the peripheral surface of the elastic roller and the peripheral surface of the rotating member are in surface contact. Thus, when the peripheral surface of the elastic roller and the peripheral surface of the rotating member are in surface contact, for example, when the elastic roller is a fixing roller and the rotating member is a pressure roller, a conveying means such as a conveying belt is used. The leading edge of the recording material, for example, recording paper, conveyed by the above is sandwiched between the peripheral surface of the elastic roller and the peripheral surface of the rotating member. Next, due to the rotation of the elastic roller and the rotating member, the fed recording medium passes between the elastic roller and the rotating member and is sent out to the other side. In this case, when the elastic roller is a fixing roller, the toner existing on the surface of the recording medium is melted by the rotating member, that is, the pressure roller, and the image of the toner is fixed on the surface of the recording medium. When the elastic roller is a transfer roller, the toner development formed on the outer peripheral surface of the photosensitive drum, which is a rotating member, is transferred to a recording material conveyed between the transfer roller and the rotating member. Then, the recording medium is passed through the gap between the transfer roller and the rotating member by sandwiching the transfer roller and the rotating member.

  Generally, when the rotating member is in contact with the elastic roller, the portion of the elastic roller that contacts the rotating member is in a depressed state. After the elastic roller and the rotating member start rotating after the surface of the rotating member is brought into contact with the surface of the elastic roller so that the surface of the elastic roller is depressed, the depressed portion of the elastic roller is not restored and is distorted. In some cases, the elastic roller may rotate. In this case, there is a possibility that a so-called paper jam occurs, in which the recording medium is not smoothly conveyed. Further, since the distortion caused by the contact of the rotating member with the elastic roller is not uniformly restored, if the elastic roller is, for example, a fixing roller, the elastic roller is fixed to the recording medium passing between the elastic roller and the rotating member. There is a significant risk that the image to be disturbed will be disturbed.

  The inventor has, for example, the quality of an image formed on a recording medium by an image forming apparatus, the conveyance of the recording medium, the occurrence of a paper jam, and various elastic rollers such as a fixing roller built in the image forming apparatus. As a result of examining the correlation, we obtained knowledge that the distortion characteristics of an elastic roller formed of a specific silicone rubber composition are related to the quality of the image, the conveyance of the recording medium, the occurrence of paper jams, etc. It was. This invention is based on this finding. The present invention contributes to improving the durability of an image forming apparatus while forming a high quality image, and does not require a complicated laminated or multilayer structure, and contributes to simplification of the structure, a high quality image And a fixing device for an image forming apparatus that contributes to improving the durability of the image forming apparatus and an image forming apparatus with excellent durability that can form a high-quality image. To do.

As means for solving the problems,
Claim 1 has a shaft body and an elastic layer provided on the outer periphery of the shaft body, and the ratio of the diameter of the shaft body to the outer diameter of the elastic layer is 25 to 60%. An elastic roller that
The elastic roller according to claim 1, wherein the compression set of the elastic layer after heating at 200 ° C for 5 hours is 10% or less.
Claim 3 is the elastic roller according to claim 1 or 2, wherein the elastic layer has an Asker C hardness of 20 to 60.
The elastic roller according to any one of claims 1 to 3, wherein the elastic layer is formed by molding an addition reaction type foamed silicone rubber composition.
Claim 5 is the elastic roller according to any one of claims 1 to 4, wherein the elastic layer has a single layer structure of a silicone rubber composition.
Claim 6 is the elastic roller according to any one of claims 1 to 5, wherein the elastic roller is a fixing roller.
A seventh aspect of the present invention is a fixing device for an image forming apparatus including the fixing roller according to the sixth aspect,
An eighth aspect of the present invention is an image forming apparatus including the elastic roller according to any one of the first to sixth aspects.

  According to this invention, since the elastic layer is formed of an elastic body and the ratio of the diameter of the shaft body to the outer diameter of the elastic layer is 25 to 60%, the elastic roller is in contact with a rotating member such as a pressure roller. Even if the elastic roller rotates and the elastic roller rotates, the elastic roller is rotated by the rotating member up to that time, even if the elastic roller is rotated and remains in a stationary state. When the pressure is no longer applied, the concave distortion of the elastic roller is resolved, and the portion of the elastic roller that is not pressed by the rotating member returns to a state close to the circumferential surface. As a result, when this elastic roller is disposed in the image forming apparatus, it comes into contact with a rotating member such as a pressure roller uniformly at a predetermined pressure and in the axial direction of the elastic roller. Therefore, the elastic roller according to the present invention can uniformly contact or abut against the rotating member in the axial direction thereof, so that it can sufficiently contribute to the formation of a high quality image and is elastic. The roller and / or rotating member does not cause uneven wear or the like, and can sufficiently contribute to improving the durability of the image forming apparatus. 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 with a predetermined pressure and in the axial direction of the elastic roller. The developer image transferred to the recording medium such as toner can be uniformly heated and / or pressurized by being in contact with or pressed against the recording medium 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.

  In addition, since the elastic layer of the elastic roller according to the present invention is formed of an elastic body, there is no need to use a plurality of different materials as described in Patent Documents 1 and 2, so the present invention Thus, it is possible to provide an elastic roller capable of forming a high-quality image at a low manufacturing cost.

  An example of the elastic roller according to the present invention will be described in detail with reference to the drawings.

  As shown in FIG. 1, an elastic roller 1 as an example of the present invention includes a shaft body 2 and an elastic layer 3 formed on the outer peripheral surface thereof, and preferably, for example, as shown in FIG. Arranged in the image forming apparatus 30 or the like.

  The shaft body only needs to have good conductive characteristics, and is usually a so-called “core metal” composed of iron, aluminum, stainless steel, brass, or the like. The shaft body may be a shaft body made conductive by plating an insulating core body such as a thermoplastic resin or a thermosetting resin. Furthermore, the shaft body may be electrically conductive with a thermoplastic resin or a thermosetting resin. A shaft formed of a conductive resin containing carbon black or metal powder as a property-imparting agent may be used.

  The elastic layer is formed of an elastic body. The elastic body is usually not limited as long as it has elasticity, and is not particularly limited with respect to its material, hardness or strength, but is generally made of a rubber material. Rubber materials include silicone rubber or silicone modified rubber, nitrile rubber, ethylene propylene rubber (including ethylene propylene diene rubber), styrene butadiene rubber, butadiene rubber, isoprene rubber, natural rubber, acrylic rubber, chloroprene rubber, butyl rubber, epichlorohydrin. Examples thereof include rubber, urethane rubber, fluorine rubber, and the like, and one or two or more mixed rubbers or modified rubbers can be used. The rubber material described above can be arbitrarily selected from a millable type or a liquid type. When this elastic roller is used as a fixing roller, a suitable rubber material for the elastic layer is preferably silicone rubber or silicone-modified rubber, and a silicone rubber compound can be used as a raw material thereof.

  Examples of the silicone rubber compound include a silicone rubber composition containing a vinyl group-containing silicone raw rubber, a silica-based filler, 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 are used alone or in combination of two or more. Can do.

Examples of the silica-based filler include reinforcing fumed silica, precipitated silica, and the like, and a surface treatment with a silane coupling agent represented by a general formula RSi (OR ′) ₃ has a high reinforcing effect. A surface-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 blending amount of the silica-based filler in the silicone rubber composition is usually 5 to 100 parts by mass with respect to 100 parts by mass of the vinyl group-containing silicone raw rubber.

  Silicone rubber compounds containing the vinyl group-containing silicone raw rubber and the silica-based filler can be easily obtained as, for example, trade names “KE series” and “KEG series” manufactured by Shin-Etsu Chemical Co., Ltd.

  The elastic layer according to the present invention comprises an addition reaction type foamed silicone rubber composition containing the silicone rubber compound, an addition reaction crosslinking agent, an addition reaction catalyst, and a foaming agent and a reaction control agent which are added as necessary. Can be formed.

  This addition reaction type foamed silicone rubber composition can be used, for example, from several minutes until it is uniformly mixed using a rubber kneader such as a two-roll, three-roll, roll mill, Banbury mixer, dounixa (kneader), etc. It can be obtained by kneading for several hours, preferably 5 minutes or more and 1 hour or less, at room temperature or under heating.

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. A suitable organohydrogenpolysiloxane is represented by the following average composition formula (1), and is preferably at least 2, preferably 3 or more (usually 3 to 200), more preferably 3 to 100 in one molecule. Those having a silicon atom-bonded hydrogen atom are preferably used.
R ¹ _b H _c SiO _{(4-bc) / 2} (1)
However, in the formula (1), ^{R 1} is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 10 carbon atoms. Further, b is 0.7 to 2.1, c is 0.001 to 1.0, and b + c is a positive number satisfying 0.8 to 3.0.

Examples of the organohydrogenpolysiloxane include trimethylsiloxy group-blocked methylhydrogenpolysiloxane at both ends, trimethylsiloxy group-blocked dimethylsiloxane / methylhydrogensiloxane copolymer at both ends, dimethylhydrogensiloxy group-blocked dimethylpolysiloxane at both ends, Both ends dimethylhydrogensiloxy group-blocked dimethylsiloxane / methylhydrogensiloxane copolymer, Both ends trimethylsiloxy group-blocked methylhydrogensiloxane / diphenylsiloxane copolymer, Both ends trimethylsiloxy group-blocked methylhydrogensiloxane / diphenylsiloxane / dimethylsiloxane copolymers, copolymers consisting of (CH _{3) 2} HSiO _1/2 units and SiO _4/2 units, (CH _{3) 2} HSiO _1/2 units Such as SiO _4/2 units and (C ₆ H ₅₎ composed of the SiO _3/2 units copolymers.

  The compounding amount of the organohydrogenpolysiloxane in the addition reaction type foamed silicone rubber composition is preferably 0.01 to 20 parts by mass with respect to 100 parts by mass of the vinyl group-containing silicone raw rubber.

  Examples of the addition reaction catalyst include group 9 or group 10 simple metals and compounds thereof, and more specifically, fine particles adsorbed on a support such as silica, alumina, or silica gel. Platinum catalyst such as platinum metal, platinous chloride, chloroplatinic acid, chloroplatinic acid hexahydrate and olefin or divinyldimethylpolysiloxane, chloroplatinic acid hexahydrate alcohol solution, palladium catalyst, rhodium catalyst, etc. Is mentioned. The addition amount of these addition reaction catalysts is sufficient as a so-called catalyst amount, and is usually converted into the amount of metal of Group 9 or Group 10 of the periodic table, and the addition reaction type foamed silicone rubber composition as a whole. It is preferably 1 to 1,000 ppm, particularly preferably 10 to 500 ppm. If the amount of addition reaction catalyst is less than 1 ppm in terms of the amount of metal in 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 foaming agent, various foaming agents can be used as long as the silicone rubber compound can be foamed, and foaming agents conventionally used for foamed rubber can also be used. Examples of the foaming agent include sodium bicarbonate and ammonium carbonate, and examples of the organic foaming agent include organic azo compounds such as diazoamino derivatives, azonitrile derivatives, and azodicarboxylic 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.

  The foamed state in the elastic layer in the present invention is preferably formed of closed cells. In that case, an organic foaming agent is suitable as a foaming agent suitable for forming a suitable elastic layer. Specific examples of suitable blowing agents include azo compounds such as azodicarboxylic amide and azobis-isobutyronitrile. In particular, dimethyl-1,1'-azobis (1-cyclohexanecarboxylate) can be preferably used. Although the content of the foaming agent varies depending on the type of the foaming agent, the elastic layer may be adjusted so that the Asker C hardness of the elastic layer is 20 to 60, preferably 30 to 50. The Asker C hardness can be measured according to JIS K 6253. When the Asker C hardness of the elastic layer is within the above range, when the elastic roller is, for example, a fixing roller, the pressure roller and the fixing roller can fix the toner on the recording medium satisfactorily, and fixing unevenness can be prevented. Can be prevented. Specifically, the content of the foaming agent for forming an elastic layer having an Asker C hardness within the above range is, for example, 0.1 to 10 parts by mass with respect to 100 parts by mass of the vinyl group-containing silicone raw rubber. In particular, it should be 0.5 to 10 parts by mass. 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, whereas if it exceeds 10 parts by mass, the silicone rubber foam It may not be possible to maintain this form, and the mechanical strength of the elastic layer may decrease. 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.

  The elastic layer having closed cells preferably has an average particle diameter of 100 to 800 μm, particularly 200 to 500 μm. The average particle diameter of the closed cells can be obtained by an arithmetic average of the maximum diameter of the bubbles existing in the visual field observed with an electron microscope. When the average particle diameter of the closed cells is within the above range, the elastic layer has an appropriate elasticity, and the distortion on the surface of the elastic roller caused by contact with the rotating member, for example, the photoreceptor, The contact can be easily removed.

  As the reaction control agent, a known reaction control agent 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.

  Examples of the various additives include, for example, fillers such as calcium carbonate, colorants, heat resistance improvers, flame retardant improvers, heat conductivity improvers, release agents, alkoxysilanes, diphenylsilanediols. Non-reinforcing silica such as pulverized quartz, diatomaceous earth, etc., capable of adjusting the Asker C hardness of an elastic layer made of a silicone functional rubber, a dispersing agent such as carbon functional silane, silanol group-blocked low molecular siloxane, etc. Etc. These various additives are blended in a desired blending amount.

  The elastic layer in the present invention is produced, for example, by foaming a silicone rubber compound by an addition reaction, and an organic peroxide crosslinking agent may be used together with the addition reaction catalyst as long as the object of the present invention is not impaired. it can.

  The organic peroxide cross-linking agent can, for example, be used alone to cross-link vinyl group-containing silicone raw rubber, but when used in combination as an auxiliary cross-linking agent for an addition reaction cross-linking agent, the physical properties of silicone rubber such as strength and strain can be obtained. More improved. 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.

  One of the important things in the present invention is that the ratio of the diameter of the shaft body to the outer diameter of the elastic layer is 25 to 60%, preferably 26 to 58%.

  When the ratio falls below the lower limit value and the ratio exceeds the upper limit value, the strain of the elastic layer in the elastic roller that contacts the rotating member increases, and the portion of the elastic roller that contacts the rotating member is Even if the rotating member comes out of contact with the rotating member, the distortion is not eliminated, and the elastic roller rotates with the distortion remaining, thereby causing trouble in conveying the recording medium and reducing the quality of the image formed on the recording medium. It will cause inconvenience. Such a phenomenon is often seen when the elastic layer is formed of an elastic body, particularly the specific silicone foam rubber.

  In the elastic roller according to the present invention, it is preferable that the compression set of the elastic layer in the elastic roller in contact with the rotating member is 10% or less. When the compression set of the elastic layer is 10% or less, the strain is restored quickly. This rapid recovery of strain is often seen when the elastic layer is formed of an elastic body, particularly the specific silicone foam rubber.

Here, the compression set of the elastic roller can be measured as follows. First, marking is made on the peripheral side surface of an elastic roller having a diameter of 29 mm by polishing, and three points along the axial direction of the elastic roller are marked, and the outer diameter of the elastic roller at that position is measured at room temperature by a laser measuring machine. taking measurement. As shown in FIG. 4 (A), the outer diameter of the elastic roller 1 in this case is D _0. As shown in FIG. 3, the elastic roller 1 is sandwiched between the compression plates 10, 10 so that the marking portion of the elastic roller contacts the compression plates 10, 10. In this state, the elastic roller 1 is held by the compression jig 11. tighten. The thickness of the spacer 12 (the length from the upper end surface of the spacer 12 in contact with the upper compression plate 10 to the lower end surface of the spacer 12 in contact with the lower compression plate 10) is 25 mm (an elastic roller having a diameter of 35 mm by polishing). In this case, the degree of tightening with the compression jig is such that the compression plates are moved close to each other by 4 mm. With the elastic roller clamped by the compression jig, the compression jig is put in a dryer at 200 ° C. and heated as it is for 5 hours. After 5 hours, the compression jig is taken out from the dryer, and the elastic roller is immediately removed from the compression jig, and the removed elastic roller is left at room temperature for 18 hours. After the standing time has elapsed, the outer diameters (length D _i shown in FIG. 4B) of the marked portions of the elastic layer in the elastic roller are measured at room temperature with a laser measuring machine. The compression set (D _x ) of the elastic layer is calculated according to the formula [(D ₀ −D _i ) / (D ₀ −25)] × 100 [%] (in the case of an elastic roller having a diameter of 35 mm by polishing) Calculates the compression set (D _x ) of the elastic layer according to the formula [(D ₀ −D _i ) / (D ₀ −31)] × 100 [%]). This compression set (Dx) indicates the compression set of the elastic layer when the elastic layer in the elastic roller is exposed to a thermal history of compressing and heating at 200 ° C. for 5 hours and then leaving open at room temperature for 18 hours. . In the elastic roller according to the present invention, when the compression set of the elastic layer is 10% or less, the image forming apparatus incorporating the elastic roller can form a high-quality image on a recording medium, It is extremely unlikely to cause body transport troubles.

  The elastic roller of the present invention can be manufactured, for example, as follows. First, as shown in FIG. 1, an adhesive or primer is applied to the outer peripheral surface of the shaft body 2 in advance by a spray method, a dipping method, or the like as necessary, and an adhesive layer or primer layer is applied to the outer peripheral surface. It is good to form. 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 addition reaction type foamed silicone rubber composition prepared 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 addition reaction type foamed silicone rubber composition is preferably extruded to a length of 109 to 190% of the desired total length of the elastic layer, and is extruded to a length of 120 to 150%. It is particularly preferred. When the addition reaction type foamed silicone rubber composition is extruded so as to have a length in the above range, the vicinity of both ends and the vicinity of the center part of the uncut elastic layer formed by curing the addition reaction type foamed silicone rubber composition Even if the physical properties, such as hardness, may not be uniform, 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 addition reaction type foamed silicone rubber composition to be extruded can be up to 190% of the total length of the desired elastic layer in consideration of productivity. In order to form an elastic layer having various physical properties, the upper limit is not necessarily 190%, and may be 200% or 300%.

  When extruding an addition reaction type foamed silicone rubber composition, if the total length of the shaft body is shorter than the length of the addition reaction type foamed silicone rubber composition to be extruded, connect an extension shaft body to both ends of the shaft body. do it. Specifically, a female screw is cut at each end face at both ends of the shaft body, a male screw that is screwed into this female screw is cut at one end face of the extension shaft body, and the female screw and the male screw are screwed together, whereby the extension shaft body is It can be a connected shaft.

  The extrusion reaction of the addition reaction type foamed silicone rubber composition may be performed under conditions sufficient to crosslink the rubber contained in the addition reaction type foamed silicone rubber composition, for example, vinyl group-containing silicone raw rubber. What is necessary is just to carry out on conditions sufficient for the foaming agent contained in a foaming silicone rubber composition to decompose or foam. For example, the extrusion molding of the addition reaction type foamed silicone rubber composition is usually performed at 100 to 500 ° C., particularly 200 to 400 ° C., heating time by a heating furnace such as an infrared heating furnace or a hot air furnace, or a heating machine such as a dryer. Is carried out by heating for several minutes to 1 hour, particularly 5 to 30 minutes.

  If desired, the addition reaction type foamed silicone rubber composition may be further subjected to secondary heating. The secondary heating is a step of more reliably crosslinking the addition reaction type foamed silicone rubber composition cross-linked 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 addition reaction type foamed silicone rubber composition formed by extrusion molding under the above-described conditions is further extruded, for example, 180 to 250 ° C., preferably 190 to 230 ° C. 1 to 24 hours, preferably 3 to 10 hours, or using a mold, for example, 130 to 200 ° C, preferably 150 to 180 ° C, 5 minutes to 24 hours, preferably 10 minutes or more This is done by heating again for 10 hours or less.

  Next, the uncut elastic layer formed in this way is cut in the vicinity of both ends of the uncut elastic layer so that it becomes an elastic layer having a desired length, and preferably cut at the same length. Is done. For example, when the uncut elastic layer is formed with a length of 109% with respect to the total length of the desired elastic layer, each end of the uncut elastic layer is cut by a total of 9%, May be cut from each end portion by 4.5%, for a total of 9%. When the length is 190% of the total length of the desired elastic layer, the uncut elastic layer Each end may be cut by a total of 90%, preferably by cutting 45% from each end by a total of 90%. 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.

  Thus, the elastic roller according to the present invention is formed. The elastic roller manufactured in this way is suitably used for various rollers of an image forming apparatus, for example, a transfer roller, a developing roller, a charging roller, a fixing roller, a pressure roller, a paper feed roller, and particularly a fixing roller. Is done. When this elastic roller is used as a fixing roller, a fixing device for an image forming apparatus is obtained.

  An example of a fixing device for an image forming apparatus (hereinafter sometimes referred to as a fixing device) and an image forming apparatus provided with the elastic roller according to the present invention will be described with reference to FIG.

  As shown in FIG. 2, 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. 2, fixing means 35 having an endless belt is the fixing device according to the present invention. 2, the fixing device 35 has 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 illustrated in FIG. 2, the developing unit 40 has an opening at a position facing the image carrier 31, and includes 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. 2, 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 is removed by the cleaning unit 37 while the image carrier 31 rotates clockwise as indicated by the arrow in FIG. 2. 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.

(Examples 1-7)
Silicone rubber compound “KE-153U” (Shin-Etsu Chemical Co., Ltd., trade name) 100 parts by mass, organohydrogenpolysiloxane 2 parts by mass as an addition reaction crosslinking agent, and dimethyl-1,1′-azobis as a foaming agent (1-cyclohexanecarboxylate), a catalytic amount of chloroplatinic acid was added as a catalyst, and an addition reaction type foamed silicone rubber composition was prepared. At this time, the addition amount of the foaming agent was adjusted so that the Asker C hardness in the elastic layer was 20 to 60. For Example 7, a catalytic amount of benzoyl peroxide, which is an organic peroxide, was added as a catalyst instead of chloroplatinic acid.

  Further, the surface of a metal shaft body having a diameter and an axial length shown in Table 1 and having SUM 22 subjected to electroless nickel plating was washed with toluene, and “Primer No. 101A / B” ( Shin-Etsu Chemical Co., Ltd., trade name) was applied.

Further, this metal shaft body obtained by the primer treatment was baked at a temperature of 150 ° C. for 30 minutes in a gear oven, cooled at room temperature for 30 minutes or more, and then the primer-treated metal shaft body and silicone rubber. The composition was integrally extruded with an extruder and fired in an IR furnace to form a sponge roller original. This was further heat-treated in a gear oven at a temperature of 200 ° C. for 5 hours, left at room temperature for 1 hour or longer, and then ground to an outer diameter of 29 mm or an outer diameter of 35 mm with a cylindrical grinder to obtain an elastic roller. . The obtained elastic roller was measured by the method for measuring compression set described above, and the value of compression set (D _x ) is shown in Table 1.

(Comparative Examples 1-5)
About Comparative Examples 1-4, it has the diameter and axial length which are shown in Table 1, and is the same addition reaction type | mold as used in the said Example and the metal shaft body which carries out the process similar to the said Example. A sponge roller prototype was formed using the foamed silicone rubber compound in the same manner as in the previous example. The sponge roller prototype was processed in the same manner as in the above example to obtain an elastic roller. For this elastic roller, the compression set (D _x ) of the elastic roller was measured in the same manner as in the previous example. The results are shown in Table 2.

  The durability of the elastic rollers produced in Examples 1 to 7 and Comparative Examples 1 to 4 was tested by the following method using a durability test apparatus 70 shown in FIG. 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 roller produced in Examples 1 to 7 and Comparative Examples 1 to 4 was mounted on the bearing of the test roller mounting portion 74, and the elastic force mounted by operating the pressing force adjusting means 75 as shown in FIG. The 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 elastic roller 76). 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 heating roller 71 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 7 had no deformation unevenness over the axial direction of the elastic layer after the test, and the uneven wear of the elastic layer could not be confirmed. Therefore, from this result, when the elastic roller produced in Examples 1 to 7 is disposed in the image forming apparatus, it can act uniformly on the contacted body in the axial direction. It was found that the image forming apparatus can sufficiently contribute to the formation of quality images and can also contribute sufficiently to the improvement of the durability of the image forming apparatus. On the other hand, the elastic roller produced in Comparative Examples 1 to 4 was 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 main part schematic diagram showing an example of the image forming apparatus according to the present invention. FIG. 3 is an explanatory view showing a state in which the elastic roller is fastened with a compression jig in order to measure the compression set of the elastic roller. FIG. 4 is an explanatory view showing the diameter of the elastic roller, FIG. 4 (A) is an explanatory view showing the diameter (D ₀ ) of the elastic roller before tightening with the compression jig, and FIG. It is explanatory drawing which shows the diameter (Dx) in the elastic roller which has. FIG. 5 is a schematic diagram showing a durability test apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Elastic roller 2 Shaft body 3 Elastic layer 10 Pressure plate 11 Compression jig 12 Spacer 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 Development Agent 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 Pressure adjusting means

Claims (8)

  An elastic roller comprising a shaft body and an elastic layer provided on an outer periphery of the shaft body, wherein a ratio of a diameter of the shaft body to an outer diameter of the elastic layer is 25 to 60%.   2. The elastic roller according to claim 1, wherein the compression set of the elastic layer after heating at 200 ° C. for 5 hours is 10% or less.   The elastic roller according to claim 1 or 2, wherein the elastic layer has an Asker C hardness of 20 to 60.   The elastic roller according to claim 1, wherein the elastic layer is formed by molding an addition reaction type foamed silicone rubber composition.   The elastic roller according to any one of claims 1 to 4, wherein the elastic layer has a single-layer structure of a silicone rubber composition.   The elastic roller according to claim 1, wherein the elastic roller is a fixing roller.   A fixing device for an image forming apparatus, comprising the fixing roller according to claim 6. An image forming apparatus comprising the elastic roller according to claim 1.

Images