JP2008000969A - Method for producing rubber roll body, silicone rubber roll, and roller for heating fixation - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a roll body which can inexpensively produce a roll body of paper feeding and others in homogeneous layer construction without the occurrence of conveyance nonuniformity. <P>SOLUTION: An axis member constituting a rotary shaft molded in advance, a hollow cylindrical inner cylinder sleeve body constituting an elastic layer molded in advance, a hollow cylindrical outer cylinder sleeve body constituting a peripheral surface layer molded in advance, and a hollow cylindrical mold to be filled with a silicone rubber raw material are provided. The method is composed of a setting process in which the axis member, the inner cylinder sleeve body, and the outer cylinder sleeve body are positioned/fixed in the mold, a packing process in which the unvulcanized liquid silicone rubber raw material is packed in the void between the axis member fixed in the setting process and the inner cylinder sleeve body and/or the void between the inner cylinder sleeve body and the outer cylinder sleeve body, and a heating process in which the silicone rubber raw material packed in the void(s) is heated and crosslinked. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for producing a rubber roll body such as a roller for conveying a paper sheet in various paper feeding devices or the like, or a heat fixing roller for heating and fixing an image of a paper sheet on which an image has been formed, a silicon rubber roll using the same, and a heating The present invention relates to a fixing roller.

  In general, roller bodies used in various paper feeding apparatuses are configured in various structures according to the purpose of transporting paper sheets and the purpose of heat-pressing in the process of transporting paper sheets. For example, a roller body used in a paper feeding device that separates paper sheets one by one is composed of a rubber material whose surface layer is made of a high friction coefficient, and a fixing roller body that heats and fixes a paper sheet to which toner ink or the like is adhered. The surface is made of a heat-resistant film material such as metal.

  In the process of conveying such a paper sheet, the roller body for separating the paper sheet, fixing the ink, and the like forms an axial core member constituting the rotating shaft and an elastic layer around it, and the surface thereof is a high friction member or a high It is formed in the layer structure formed with a heating member. For example, in Patent Document 1 (Japanese Patent Laid-Open No. 9-114281), an elastic layer of silicon rubber is formed around a shaft member as a fixing roller, and a heat-resistant release layer made of a fluororesin is formed on the surface thereof. Patent Document 2 (Japanese Patent Laid-Open No. 4-177282) discloses a roll structure in which a silicon rubber layer is formed around a cored bar and a porous foamed sponge layer is formed around the core as a similar fixing roller. Yes.

  Conventionally, silicon rubber rolls are frequently used as such conveying rollers or fixing rollers. This is because silicon rubber is (1) rich in heat resistance and chemical resistance, (2) excellent in frictional properties and elastic properties, and (3) its elastic properties change thermally over time. This is due to a few things.

  Therefore, conventionally, when such a silicon rubber roll having a multilayer structure is molded, for example, in Patent Document 3 (Japanese Patent Application Laid-Open No. 58-71146), a silicon rubber sheet molded into a sheet shape is wound around a core metal to form a roll. A molding method for forming and then heat vulcanizing is disclosed. There is also known a method of filling a mold with an uncrosslinked liquid material when molding silicon rubber and solidifying the mold by heating vulcanization in an electric furnace, for example.

  On the other hand, when a roller body used for transporting and fixing paper sheets is configured in a plurality of layer shapes, (1) the shape dimension, particularly roundness, is ensured to be constant, and there is little variation, (2) paper It is required that the pressure and frictional force exerted on the leaf are constant, (3) stable over time and in a temperature environment, and (4) easy and inexpensive to process.

  In particular, as the heat fixing roller, even if the pressure contact force applied to the paper sheet changes or the frictional force changes, image fixing spots are caused. This is a serious problem as the speed and size of the apparatus are increased. For example, when the temperature of the roller surface is controlled to be high for speeding up, an elastic layer such as silicon rubber expands due to heat, and the peripheral speed of the roll surface changes to cause blurring or distortion in the fixed image. .

Accordingly, the present inventor has come up with the idea that a porous sponge layer absorbs thermal expansion at high temperatures and thermal contraction at cooling by forming a sponge-like porous layer with silicon rubber around the shaft core member. As a result, it has been found that it is possible to solve the problem of changes in the outer diameter or elastic properties of the roll surface layer due to temperature changes.
JP-A-9-114281 JP-A-4-177282 JP 58-71146 A

  As described above, when one or more porous elastic layers are formed around a metal or other shaft core member (core metal) and the outer peripheral surface layer is formed on the outer periphery thereof, the following problem occurs. When adopting a processing method in which each elastic layer is formed by winding a sheet-like material as in the above-mentioned Patent Document 3, a step-like dimensional difference at the joint portion of the sheet end surface, or an elastic property due to an adhesive changes, There is a problem that the processing cost becomes high.

  Further, for example, an unvulcanized liquid rubber material mixed with a foaming agent is injected and filled into a mold, and a foaming reaction and a vulcanization reaction are performed in the mold to form a cylindrical elastic body. The conventional rubber roll layer structure employs a method in which a sleeve member forming an outer peripheral surface layer separately formed on a cylindrical elastic body is bonded with an adhesive. Molding with such an injection mold is not a continuous process like extrusion molding, so the processing cost is high, and the molded elastic body cannot be machined accurately and the inner and outer circumferences of the elastic body are polished and dimensioned. Since secondary processing to correct is required, there is a problem that the cost is further increased.

  And it is difficult to process the above-mentioned shaft core member, cylindrical elastic body, and outer sleeve body in a constant manner so that the thickness of each layer does not vary in the circumferential direction after ensuring the roundness, The work of integrating the above three members while adjusting the dimensions by secondary processing such as polishing after individually forming them requires skill, and causes a high manufacturing cost.

Further, when a silicon rubber roller is used as the heat fixing roller, the following requirements are required.
(1) Rich in heat resistance and chemical resistance,
(2) Low thermal conductivity and small heat capacity,
(3) No change in sheet conveyance unevenness and pressure contact force due to temperature changes at high and low temperatures,
(4) The roll diameter does not change due to rapid heating / cooling,
(5) The layer thickness of the roll layer constituting the layer structure is uniform and roundness is maintained, and it has uniform elastic characteristics,
(6) Easy processing and excellent heat resistance and durability,
In order to meet such requirements, the conventional fixing roller has a problem in that the roll diameter changes due to temperature change, and the roundness and thickness of the roll layer vary.

  Accordingly, the main object of the present invention is to provide a method for manufacturing a roll body that does not cause unevenness of conveyance and can manufacture paper rolls and other roll bodies at a low cost with a homogeneous layer structure. Another object of the present invention is to provide a silicon rubber roll and a heat fixing roll that can apply a uniform pressing force to a roll body used for sheet conveyance or fixing in various image forming apparatuses without causing uneven conveyance. Yes.

  The present invention adopts the following configuration in order to solve the above problems. First, a method for producing a silicon rubber roll according to the present invention includes a shaft member that is molded in advance and forms the rotating shaft, a hollow cylindrical inner cylinder sleeve that is molded in advance and forms the elastic layer, and is molded in advance. A hollow cylindrical outer cylinder sleeve constituting the outer peripheral surface layer and a hollow cylindrical molding die filled with a silicon rubber material are provided. And a set step of positioning and fixing the shaft core member, the inner cylinder sleeve body and the outer cylinder sleeve body in the mold, and the shaft core member and the inner cylinder sleeve body fixed in the setting step A filling step of filling an unvulcanized liquid silicone rubber material into a gap between and / or a gap between the inner cylinder sleeve body and the outer cylinder sleeve body, and heating the silicon rubber material filled in the gap And a heating step for crosslinking.

  As a result, the shaft core member, the inner cylinder sleeve body, and the outer cylinder sleeve body, which are each processed by an arbitrary method, are sequentially fitted, and the void formed therebetween is filled with unvulcanized liquid silicon. In order to integrally fix the three members by superheat vulcanization, the shaft core member and the inner cylindrical sleeve body and the inner cylindrical sleeve body and the outer cylindrical sleeve body are firmly fixed by silicon rubber. Become.

  The inner cylinder sleeve body is made of, for example, silicon rubber formed into a tube shape by extrusion processing, and the inner cylinder sleeve body contains a plurality of bubbles. In this case, the plurality of bubbles are constituted by closed cells or open cells communicating with each other. In particular, if the inner sleeve body contains continuous bubbles, which are a chain of bubbles communicating with each other, the thermal expansion of the elastic layer is absorbed by the inner bubbles even if the temperature of the surface layer is increased, and the outer diameter of the roll body can be changed. Absent.

  Then, when the liquid silicon rubber material is injected into the above-mentioned gap and heated and vulcanized, one of the following first, second, and third methods is adopted. First, the first method is to position and fix the inner cylinder sleeve body in the mold by fitting the outer circumference of the shaft core member, and the gap between the inner cylinder sleeve body and the outer cylinder sleeve body. Is filled with the above-mentioned unvulcanized liquid silicone rubber material. As a result, the inner cylinder sleeve body has its inner circumference regulated by a metal or other shaft core member, and at the same time, its outer circumference is regulated by silicon rubber filled between the outer cylinder sleeve body and an elastic layer having a uniform thickness. And the roundness is accurate.

  The second method is to position and fix the inner cylinder sleeve body in the molding die by fitting the inner cylinder sleeve body to the inner periphery of the outer cylinder sleeve body, and a gap between the inner cylinder sleeve body and the shaft core member. The unvulcanized liquid silicon rubber material is filled in and vulcanized and cured. As a result, the outer circumference of the inner cylinder sleeve body is regulated in shape by the outer cylinder sleeve body such as a metal film, and at the same time, the inner circumference is regulated in shape by silicon rubber filled between the core member and the uniform. A thick elastic layer is formed, and the roundness is accurate.

  In the third method, the inner cylinder sleeve body is positioned and fixed in the mold by a sleeve fixing member so as to form gaps between the shaft core member and the outer cylinder sleeve body, respectively. The voids are filled with the unvulcanized liquid silicon rubber material and heat vulcanized. In this way, the inner cylinder sleeve body is fixed by the silicon rubber material injected between the inner circumference and the shaft core member, and the outer circumference and the outer cylinder sleeve body are fixed by the silicon rubber material injected between them. The shaft core member, the inner cylinder sleeve body, and the outer cylinder sleep body can be reliably integrated without using an agent.

  In the case of the third method, an elastic layer having a more uniform thickness can be formed by gradually pulling out the sleeve fixing member from the molding die as the liquid silicon rubber material is filled. The outer sleeve member is formed of a metal film material or a heat resistant material obtained by coating a resin on the metal film material. Thereby, a suitable heat fixing roller can be constituted.

  Next, a silicon rubber roll according to the present invention includes a metal or other shaft core member, a silicon rubber layer formed on the outer periphery of the shaft core member, and an outer peripheral surface layer formed on the outer periphery of the silicon rubber layer. A roll having the silicon rubber layer formed in a sleeve shape, and a liquid filled in a gap between the porous elastic layer and the shaft core member and / or the outer peripheral surface layer. It consists of a silicon rubber layer. This liquid silicone rubber layer is solidified by heat vulcanization after injection. Thus, the shaft core member, the porous elastic layer, and the outer peripheral surface layer are fixed and integrated without using an adhesive.

  Next, a fixing roller according to the present invention includes a metal or other shaft core member, a silicon rubber layer formed on the outer periphery of the shaft core member, and an outer peripheral surface layer formed on the outer periphery of the silicon rubber layer. The silicon rubber layer is a sleeve-shaped porous elastic layer, and a liquid filled in a gap between the porous elastic layer and the shaft core member and / or the outer peripheral surface layer. It consists of a silicon rubber layer. The outer peripheral surface layer is composed of a metal film material or a heat-resistant material coated with a resin on the metal film material, and the shaft core member, the porous elastic layer, and the outer peripheral surface layer are formed by heat vulcanization of the liquid silicon rubber. Integrate.

  The present invention comprises a core member formed in advance when the roll body is composed of a shaft member, an elastic layer around the roll member, and an outer peripheral surface layer, and an inner cylindrical sleeve body and a surface layer forming the elastic layer. The outer cylinder sleeve body to be positioned is fixed in the mold so as to maintain the roundness, and the void formed between the three members is filled with an unvulcanized liquid silicone rubber material and heated. Therefore, the shaft core member, the inner cylinder sleeve body, and the outer cylinder sleeve body are firmly fixed and firmly integrated without using an adhesive.

  Therefore, since there is no adhesive between the surface layer and the porous elastic layer, heat applied to the surface layer is not propagated to the outside by the adhesive having high thermal conductivity. At the same time, an air layer (bubbles) is formed in the porous elastic layer inside the surface layer. This air layer with the lowest thermal conductivity further suppresses heat propagation from the surface layer and reduces heat loss. Will be.

  In addition, since the porous elastic layer formed between the shaft center member and the outer peripheral surface layer is positioned in the mold and filled with liquid silicon rubber in the gap, these layers constituting the roll layer The roundness of the member is ensured accurately. For this reason, the elastic characteristic which presses a sheet | seat is kept uniform, without varying in a roll rotation direction.

  Furthermore, since the porous elastic layer of silicon rubber is disposed inside the outer peripheral surface layer, the heat capacity of the roll body itself is small, and this rubber layer contains thermal expansion during heating and thermal contraction during cooling. It is possible to press-carry and convey sheets with a stable roll diameter without absorbing bubbles and enlarging or contracting the roll diameter. In this case, if the bubbles in the elastic layer are composed of open cells (chains of bubbles communicating with each other), the expanded air in the bubbles is discharged to the outside during thermal expansion, and the air is sucked in from the outside during cooling. Can reduce austerity.

  In addition, the porous elastic layer is formed by forming a cylindrical inner sleeve by a suitable processing method in advance and integrating it by injecting a liquid silicon rubber material to form a roll body. As the elastic layer, for example, one that is mass-produced by continuous processing such as extrusion molding can be used, and the manufacturing cost can be significantly reduced as compared with the case where it is individually vulcanized in a conventional mold. The present invention has the above-mentioned remarkable effects.

  The present invention will be described in detail below based on the illustrated embodiment. FIG. 1 is a perspective view showing a structure of a silicon rubber roller according to the present invention, and FIGS. 2 to 4 are explanatory views of a roll body manufacturing method according to the present invention. FIG. 2 is an explanatory diagram of the first embodiment, FIG. 3 is an explanatory diagram of the second embodiment, and FIG. 4 is an explanatory diagram of the third embodiment. FIG. 5 is an enlarged sectional view showing a layer sectional structure.

  First, the structure of the silicon rubber roll A according to the present invention will be described with reference to FIG. The silicon rubber roll A includes a shaft core member 1, a porous elastic layer 2 on the outer periphery thereof, and an outer peripheral surface layer 3 on the outer periphery thereof. The shaft core member 1 is formed of a steel material such as an aluminum alloy or SUS steel material into a cylindrical shape or a columnar shape by, for example, drawing, and constitutes a rotating shaft of the silicon rubber roll A. The shaft member 1 has a cylindrical or columnar shape, and its outer diameter Dy1 is made of a metal material, a synthetic resin material, or the like so as to withstand the mechanical strength that supports the entire roller body. In this case, the shaft core member is preferably made of a material having high mechanical strength when used as a heat-fixing roller and simultaneously having as low a thermal conductivity as possible.

  The porous elastic layer 2 is composed of a hollow cylindrical inner cylinder sleeve body 21 made of a silicon rubber material. The hollow inner diameter Dx2 is a size that fits the shaft core member 1, and the outer diameter Dy2 is the outer peripheral surface. The outer cylinder sleeve body 31 that forms the layer 3 is configured to fit. This dimensional relationship will be described later. The inner sleeve member 21 is foamed and vulcanized by mixing a foaming agent and a vulcanizing agent in a silicon rubber material such as an organic compound mainly composed of silica (Sio2). As the molding method, it is molded into the above-described cylindrical shape by injection, compression, extrusion molding or the like, which will be described later. In this case, it is already known that the manufacturing cost is reduced when the tube is continuously formed by extrusion. For this reason, it is preferable that the porous elastic layer 2 of the present invention is formed by cutting an extruded silicon rubber tube into a predetermined length to form the inner cylindrical sleeve body 21. In addition, the inner cylinder sleeve body 21 can be formed by an appropriate processing method.

  By such molding, a large number of internal bubbles 22 are formed by foaming of the foaming agent in the inner sleeve body 21 made of silicon rubber, and the bubbles 22 are single-bubble elastic materials in which a plurality of independent fine cavities are distributed in the silicon rubber. A layer (closed cell) and a continuous bubble-like elastic layer (open cell) in which a plurality of bubbles communicating with each other are distributed and formed are formed. FIG. 5A shows a conceptual structure of the single-bubble elastic layer, in which a plurality of large and small bubbles are contained in the rubber layer, and air is sealed inside. FIG. 2B shows the conceptual structure of the open-cell elastic layer. A plurality of large and small bubbles are contained in the rubber layer in a state of being linked to each other, and the internal air is connected to the outside.

  The outer peripheral surface layer 3 is composed of an outer sleeve member 31, is formed of a rubber material having a predetermined coefficient of friction when used as a conveying roller, and is formed of a heat resistant material when used as a fixing roller. In the case of this fixing roller, a sleeve body in which the outer peripheral surface layer 3 is coated with a metal film material, for example, a base film of stainless steel, nickel alloy, copper alloy or the like, with a fluororesin is a typical configuration. For the metal substrate, an appropriate material is selected from the electrical characteristics such as conductive characteristics and electromagnetic characteristics, mechanical strength, and heat conduction characteristics in relation to the heating method. Further, the surface material is selected in relation to the fixing ink such as toner, and the fluororesin is known as a material with less toner ink adhesion contamination. And the outer cylinder sleeve body 31 comprised with such a raw material is formed in the internal diameter Dx3 fitted to the outer periphery of the said inner cylinder sleeve body 21, The outer diameter Dy3 is formed in the predetermined | prescribed roll outer diameter.

  The shaft core member 1, the porous elastic layer 2, and the outer peripheral surface layer 3 are integrated as follows to constitute the silicon rubber roll A. As described above, the shaft core member 1 is formed in a cylindrical or columnar shape having the outer diameter Dy1, and the porous elastic layer 2 is formed by the hollow cylindrical inner sleeve member 21 having the inner diameter Dx2 and the outer diameter Dy2 as described above. The outer peripheral surface layer 3 is formed of an outer sleeve member 31 having an inner diameter Dx3 and an outer diameter Dy3.

  Accordingly, the shaft core member 1, the inner cylinder sleeve body 21, and the outer cylinder sleeve body 31 are positioned and fixed in the molding die 50, and an uncrosslinked liquid silicon rubber material is injected into the molding die 50. As a result, the liquid silicon rubber material is formed in the gap G1 formed between the shaft core member 1 and the inner cylinder sleeve body 21 and the gap G2 formed between the inner cylinder sleeve body 21 and the outer cylinder sleeve body 31. Filled. When heated and vulcanized in this state, the filled silicon rubber material is cured and a rubber roll body A is formed in which the shaft core member 1, the inner cylinder sleeve body 21, and the outer cylinder sleeve body 31 are closely fixed and integrated.

  Hereinafter, in accordance with the process explanatory diagram shown in FIG. 7 for details, when (A) a silicon rubber filling layer is formed between the shaft core member 1 and the inner sleeve member 21, (B) the inner sleeve member 21 and the outer sleeve When forming a silicon rubber filled layer between the sleeve body 31 and (C) silicon between the shaft core member 1 and the inner cylinder sleeve body 21 and between the inner cylinder sleeve body 21 and the outer cylinder sleeve body 31. In the case of forming a rubber-filled layer, each embodiment will be described.

(A) An embodiment in which a silicon rubber filled layer is formed between the shaft core member 1 and the inner sleeve member 21 will be described below.
As shown in FIG. 2, a shaft core fixing member (shaft fixing groove; hereinafter the same) 51 for fixing the shaft core member 1 and an outer cylinder fixing member 52 for fixing the outer sleeve body 31 are provided in the mold 50. In the illustrated example, a shaft fixing concave groove is provided in the cap member 53, the cap member 53 is detachably attached to the molding die 50 by a screw groove, and the outer cylinder fixing member 52 is constituted by an inner wall of the molding die 50.

  On the other hand, the outer diameter Dy2 of the inner cylinder sleeve body 21 is formed larger than the inner diameter Dx3 of the outer cylinder sleeve body 31 (Dy2> Dx3), and the inner cylinder sleeve body 21 is press-fitted into the outer cylinder sleeve body 31 so as to integrate them. It has become. In this case, a skin layer (skin layer) is formed on the inner sleeve member 21 at the time of molding, but it is preferable to remove this skin layer by polishing or the like. The reason will be described later. Further, when the thickness and roundness are not accurate by the processing method of the inner cylinder sleeve body 21, the dimensional accuracy is adjusted by polishing.

  After the inner cylinder sleeve body 21 is press-fitted into the outer cylinder sleeve body 31 without being subjected to the above polishing process or without being polished, the two are integrated, and then the inner wall of the mold 50 (the aforementioned outer cylinder fixing member; Similarly, it is fixedly fitted to 52. The mold inner wall 52 and the shaft-fixing groove 51 are configured such that their circular centers coincide with each other so that the roundness is uniform. Therefore, the shaft core member 1 is fixed to the shaft fixing groove 51 and the outer sleeve member 31 is fixed to the inner wall 52 of the mold.

  Next, unvulcanized (uncrosslinked) liquid silicon is injected from the filling port 54 of the mold 50. The injection pressure at this time is set to a pressure at which silicon rubber enters the gap G1 formed between the outer periphery of the shaft core member 1 and the inner space of the inner cylindrical sleeve body 21. Then, the gap G1 is filled with a silicon rubber material. Next, the mold 50 is heated to a predetermined temperature to vulcanize and cure the uncrosslinked silicon rubber material.

  The silicon roll A molded as described above has a layer structure of the shaft core member 1, the filled silicon rubber layer 25, the porous silicon rubber layer 24, and the outer peripheral surface layer 3. In this state, the shaft core member 1 and the inner cylinder sleeve body 21 are tightly integrated with the filled silicon rubber layer 25, and the inner cylinder sleeve body 21 and the outer cylinder sleeve body 31 that are press-fitted and fixed to each other by the filled silicon rubber layer 25. And are more closely fixed. Therefore, even if a rotational force is applied using the shaft core member 1 as a rotation axis, the porous silicon rubber layer 24 and the outer peripheral surface layer 3 are not separated or twisted. Even if the outer peripheral surface layer 3 is heated at a high temperature, the outer diameter of the roll is not deformed by the action of bubbles in the porous silicon rubber layer 24.

  The heat conduction when the skin (skin layer) formed at the time of molding the inner cylinder sleeve 21 is removed by polishing will be described. The heat of the outer peripheral surface layer 3 is transferred to the inner porous elastic layer 2 by heat conduction. Although it is propagated, the heat propagation can be kept low by removing the skin layer. That is, the outer cylinder sleeve body 31 forming the outer peripheral surface layer 3 and the inner cylinder sleeve body 21 forming the porous elastic layer 2 are press-fitted without using an adhesive in a state in which the skin layer (skin layer) of the roll body is removed. Since the surface of the porous elastic layer 2 is fixed, an air layer is formed between the outer peripheral surface layer 3 and the sponge-like uneven surface 26 shown in FIG. The presence of this air layer suppresses the heat of the outer peripheral surface layer 3 from being propagated to the internal porous elastic layer 2 by the air having the smallest thermal conductivity. Therefore, it is preferable to remove the inner cylinder sleeve body 21 by polishing or peeling the skin (skin layer) at the time of molding.

(B) An embodiment in which a silicon rubber filling layer is formed between the inner cylinder sleeve body 21 and the outer cylinder sleeve body 31 will be described below.
As shown in FIG. 3, the shaft core fixing member (shaft fixing groove) 51 for fixing the shaft core member 1 in the molding die 50 and the outer cylinder fixing member (molding die inner wall) 52 for fixing the outer cylinder sleeve body 31 are described above. It is provided in the same way. In the illustrated example, an outer cylinder fixing member is formed by a shaft fixing groove 51 and a mold inner wall 52 in a cap member 53.

  On the other hand, the inner diameter Dx2 of the inner cylinder sleeve body 21 is formed smaller than the outer diameter Dy1 of the shaft core member 1 (Dx2 <Dy1), and the shaft core member 1 is press-fitted into the inner cylinder sleeve body 21 to integrate them. ing. In this case, when the thickness and roundness are not accurate by the processing method of the inner cylinder sleeve body 21, the inner diameter dimension of the inner cylinder sleeve body 21 is adjusted by polishing.

  The shaft core member 1 is pressed into the inner cylinder sleeve body 21 without being subjected to the above polishing process or integrated, and the both are integrated, and then the shaft fixing groove in the mold 50 (the above-described shaft core fixing) (Member) 51 is fixedly fitted. Further, the outer cylinder sleeve body 31 is fixed to the inner wall 52 of the mold. Next, unvulcanized (uncrosslinked) liquid silicon is injected from the filling port 54 of the mold 50. The injection pressure at this time is set to a pressure at which silicon rubber enters the gap G2 formed between the outer periphery of the inner sleeve member 21 and the inner wall of the outer sleeve member 31. Then, the gap G2 is filled with a silicon rubber material. Next, the mold 50 is heated to a predetermined temperature to vulcanize and cure the uncrosslinked silicon rubber material.

  The silicon rubber roll A molded as described above has a layer structure of the shaft core member 1, the porous silicon rubber layer 24, the filled silicon rubber layer 25, and the outer peripheral surface layer 3. In this state, the inner cylinder sleeve body 21 and the outer cylinder sleeve body 31 are tightly integrated with the filled silicon rubber layer 25, and the shaft core member 1 and the inner cylinder sleeve body 21 that are press-fitted and fixed to each other by the filled silicon rubber layer 25. And are more closely fixed. Therefore, even if a rotational force is applied using the shaft core member 1 as a rotation axis, the porous silicon rubber layer 24 and the outer peripheral surface layer 3 are not separated or twisted. Even if the outer peripheral surface layer 3 is heated at a high temperature, the outer diameter of the roll is not deformed by the action of bubbles in the porous silicon rubber layer 24.

(C) An embodiment in which a silicon rubber filling layer is formed between the shaft core member 1 and the inner cylinder sleeve body 21 and between the inner cylinder sleeve body 21 and the outer cylinder sleeve body 31 will be described below.
As shown in FIG. 4, the shaft core fixing member (shaft fixing groove) 51 for fixing the shaft core member 1 in the mold 50, the sleeve fixing member 52a for fixing the inner cylinder sleeve body 21, and the outer cylinder sleeve body 31 are fixed. An outer cylinder fixing member is provided.

  In the illustrated example, an outer cylinder fixing member is constituted by a shaft fixing concave groove 51 and a mold inner wall 52 in a cap member 53, and a sleeve fixing member 52a is constituted by a cylindrical holder for fitting and fixing the inner cylinder sleeve body 21. . The sleeve fixing member 52a is supported on the molding die 50 so as to be movable in the horizontal direction in the figure. The shaft fixing concave groove 51, the sleeve fixing member 52a, and the inner wall 52 of the mold are made to coincide with the center of the circle so that the roundness of the shaft core member 1, the inner cylindrical sleeve body 21, and the outer cylindrical sleeve body 31 to be supported is aligned. It is. If the thickness and roundness are not accurate by the processing method of the inner cylinder sleeve body 21, the inner diameter dimension of the inner cylinder sleeve body 21 is adjusted by polishing. The shaft core member 1 is attached to the shaft fixing concave groove 51, the inner cylinder sleeve body 21 is attached to the sleeve fixing member 52a, and the outer cylinder sleeve body 31 is attached to the inner wall 52 of the molding die without performing the polishing process. Each is fitted and positioned.

  Next, unvulcanized (uncrosslinked) liquid silicon is injected from the filling port 54 of the mold 50. The injection pressure at this time is that silicon rubber is applied to the gap G1 formed between the shaft core member 1 and the inner cylinder sleeve body 21 and the gap G2 formed between the inner cylinder sleeve body 21 and the outer cylinder sleeve body 31. Set the pressure to penetrate. Then, the gap G1 and the gap G2 are filled with a silicon rubber material. Next, the mold 50 is heated to a predetermined temperature to vulcanize and cure the uncrosslinked silicon rubber material.

  The silicon rubber roller A molded as described above has a layer structure of the shaft core member 1, the filled silicon rubber layer 25a, the porous silicon rubber layer 24, the filled silicon rubber layer 25b, and the outer peripheral surface layer 3. In this state, the shaft core member 1 and the inner cylindrical sleeve body 21 are tightly fixed by the filled silicon rubber layer 25a, and similarly, the inner cylindrical sleeve body 21 and the outer cylindrical sleeve body 31 are tightly integrated by the filled silicon rubber layer 25b. It becomes. Therefore, even if a rotational force is applied using the shaft core member 1 as a rotation axis, the porous silicon rubber layer 24 and the outer peripheral surface layer 3 are not separated or twisted. Even if the surface layer 3 is heated at a high temperature, the outer diameter of the roll is not deformed by the action of bubbles in the porous silicon rubber layer 24.

  As described above, the silicon rubber roll A composed of the shaft core member 1, the porous elastic layer 2, the outer peripheral surface layer 3, and the filled silicon rubber layer formed between these layers integrated in a laminated manner as described above is as follows. Thus, it is used as a heat fixing roller. As shown in FIG. 6, a sheet is fed from a paper feeding unit to a printing unit such as an electrostatic drum 40, and an electrostatic latent image is formed on the electrostatic drum 40 by irradiating a laser beam from a laser emitter 41. A toner ink is attached to the latent image by the developing device 42. The toner image attached on the drum is transferred onto the sheet by the transfer charger 43.

  The toner image transferred onto the sheet in this way is fixed by being heat-pressed by the fixing roller 44. The fixing roller 44 is composed of a pair of pressure contact rollers 44a and 44b, and the surface of each roller is formed of an outer peripheral surface layer f1 such as the aforementioned fluororesin film to which toner does not adhere. The outer peripheral surface layer f1 is provided with an elastic layer f2 (the aforementioned porous elastic layer 2) in order to press the sheet uniformly. The elastic layer f2 preferably contains bubbles (closed cells or open cells) for the reasons described later. The elastic layer f2 is fitted with a shaft core member that constitutes the rotation shaft f3.

  At least one of the pair of pressure rollers 44a and 44b that are in pressure contact with each other in the above configuration is equipped with a heating means 45. For example, the following method is adopted as the configuration of the heating means 45. The first method is a method of providing a heat generating layer (not shown) between the elastic layer f2 and the surface layer f1. A current is supplied to the heat generating layer to raise the temperature of the surface layer to a predetermined temperature. The second method is a method in which a cavity is formed in the elastic layer f2, and a heating element such as a ceramic heater is built in the cavity.

  The third method is an induction heating method. For example, one surface layer f1 (sleeve body in the above-described embodiment) of the pressure roller is formed of a conductive layer made of a conductive magnetic material such as iron, nickel, and SUS and its surface. It is composed of a fluororesin layer (for example, polyimide resin) that coats. An exciting coil is arranged on the outer periphery of the pressure roller and heated.

In the fixing roller 44 configured as described above, when the outer peripheral surface layer f1 is heated and heated by the heating unit 45, the inner cylinder sleeve body 21 and the outer cylinder sleeve body 31 perform the following functions.
(1) The heating time and cooling time can be shortened (warming up time is shortened).
The heat applied to the outer peripheral surface layer 3 can keep the thermal conductivity low when propagating to the porous elastic layer 2 inside the outer peripheral surface layer 3. In other words, the outer cylinder sleeve body 31 that forms the outer peripheral surface layer 3 and the inner cylinder sleeve body 21 that forms the porous elastic layer 2 are fixed by press-fitting or filling silicon rubber layer 25 without using an adhesive. The bubbles 22 in the porous elastic layer 2 have the effect of suppressing the thermal conductivity of the inner cylindrical sleeve body 21 and suppressing the heat of the outer peripheral surface layer 3 from being propagated into the inner cylindrical sleeve body 21.

  Further, when removing the molding skin (skin layer) formed on the inner sleeve 21, the surface of the porous elastic layer 2 is a sponge-like uneven surface 26 and the air bubbles 22 a between the outer peripheral surface layer 3. Form. At this time, since the thermal conductivity of air is smaller than that of silicon rubber, a large number of fine bubbles 22a are formed between the outer peripheral surface layer 3 and the porous elastic layer 2 to gradually reduce the propagation of heat. In particular, conventionally, even if air bubbles are mixed in the elastic layer, heat is transferred from the skin layer (skin layer) and the adhesive layer to the outer periphery of the roll body and is released to the outside through the shaft core member from the portion having the highest thermal conductivity of the roll body. On the other hand, since the adhesive layer and the skin layer are not present, the release of heat is remarkably reduced.

(2) The thermal deformation of the roll body due to rapid heating and rapid cooling is improved.
Even when the outer peripheral surface layer 3 (outer cylinder sleeve body 31) is rapidly heated and cooled, there is little thermal deformation of the porous elastic layer 2 (inner cylinder sleeve body 21), and a constant pressing force is always applied to the sheet. I can do it. By forming the internal bubbles 22 in the porous elastic layer 2, the change in the outer shape is reduced even if the silicon rubber layer is thermally expanded and contracted.

The perspective view which shows the structure of the silicone rubber roller concerning this invention. The manufacturing method of the roll body concerning this invention is shown, The figure is explanatory drawing of the 1st Embodiment. Explanatory drawing which shows 2nd Embodiment of the manufacturing method different from FIG. Explanatory drawing which shows 3rd Embodiment of the manufacturing method different from FIG. It is explanatory drawing of the layer structure in the roll structure of FIG. 1, (a) is a cross-sectional structure at the time of containing a single bubble-like bubble in an elastic layer, (b) is the case at the time of making an open-cell bubble contained in an elastic layer. A cross-sectional structure is shown. FIG. 3 is a schematic explanatory diagram of a fixing roller in an image forming apparatus. Process explanatory drawing of the manufacturing method shown in FIG. 2 thru | or FIG.

Explanation of symbols

A Silicon roll Dx2 Inner cylinder sleeve body 21 inner diameter Dx3 Outer cylinder sleeve body 31 inner diameter Dy1 Axle core member outer diameter Dy2 Inner cylinder sleeve body outer diameter Dy3 Outer cylinder sleeve body 31 outer diameter 1 Axle core member 2 Porous elastic layer 3 Outer peripheral surface layer 21 Inner cylinder sleeve body 22 Inner bubble 22a Bubble 24 Porous silicon rubber layer 25 Filled silicone rubber layer 26 Sponge-like uneven surface 31 Outer cylinder sleeve body 44 Fixing roller 45 Heating means 50 Mold 51 Core fixing member (shaft fixing groove)
52 Outer cylinder fixing member (mold inner wall)
52a Sleeve fixing member 53 Cap member 54 Filling port

Claims (9)

A rotation axis;
An elastic layer such as silicon rubber formed around the rotating shaft;
An outer peripheral surface layer formed around the elastic layer, and a method for producing a rubber roll body,
A shaft member formed in advance and constituting the rotating shaft;
A hollow cylindrical inner cylinder sleeve that is pre-formed and constitutes the elastic layer;
A hollow cylindrical outer cylinder sleeve that is preformed and constitutes the outer peripheral surface layer;
A hollow cylindrical mold filled with a silicon rubber material,
A set step of positioning and fixing the shaft core member, the inner cylindrical sleeve body, and the outer cylindrical sleeve body in the molding die;
Liquid silicone rubber in an unvulcanized state in the gap between the shaft core member and the inner cylinder sleeve body fixed in the setting step and / or the gap between the inner cylinder sleeve body and the outer cylinder sleeve body A filling process for filling the material;
A heating step of heating and crosslinking the silicon rubber material filled in the gap,
A method for producing a rubber roll body comprising: The inner sleeve body is made of silicon rubber formed into a tube shape by extrusion,
2. The rubber roll body according to claim 1, wherein the inner cylinder sleeve body includes a plurality of bubbles, and the plurality of bubbles are constituted by closed cells or open cells that are connected to each other and chained to each other. Method. The inner cylinder sleeve body is positioned and fixed in the molding die by fitting to the outer periphery of the shaft core member, and the unvulcanized state is formed in the gap between the inner cylinder sleeve body and the outer cylinder sleeve body. The method for producing a rubber roll body according to claim 1, wherein the liquid silicon rubber material is filled. The inner cylinder sleeve body is positioned and fixed in the mold by fitting into the inner periphery of the outer cylinder sleeve body, and the unvulcanized space is formed in the gap between the inner cylinder sleeve body and the shaft core member. The method for producing a rubber roll body according to claim 1, wherein the liquid silicon rubber material in a state is filled. The inner cylinder sleeve body is positioned and fixed by a sleeve fixing member in the mold so as to form gaps between the shaft core member and the outer cylinder sleeve body, and the unvulcanized parts are respectively formed in the gaps. The method for producing a rubber roll body according to claim 1, wherein the liquid silicon rubber material in a state is filled. 6. The method for producing a rubber roll body according to claim 5, wherein the sleeve fixing member is gradually pulled out from the mold as the liquid silicon rubber material is filled. The method for producing a rubber roll body according to any one of claims 1 to 6, wherein the outer sleeve member is formed of a metal film material or a heat resistant material obtained by coating a resin on the metal film material. Metal and other shaft core members,
A silicon rubber layer formed on the outer periphery of the shaft core member;
A roll having an outer peripheral surface layer formed on the outer periphery of the silicon rubber layer,
The silicon rubber layer includes a porous elastic layer formed in a sleeve shape, and a liquid silicon rubber layer filled in a gap between the porous elastic layer and the shaft core member and / or the outer peripheral surface layer. And
The silicon rubber roll, wherein the shaft core member, the porous elastic layer, and the outer peripheral surface layer are integrated by heat vulcanization of the liquid silicon rubber. Metal and other shaft core members,
A silicon rubber layer formed on the outer periphery of the shaft core member;
A roll having an outer peripheral surface layer formed on the outer periphery of the silicon rubber layer,
The silicon rubber layer includes a porous elastic layer formed in a sleeve shape, and a liquid silicon rubber layer filled in a gap between the porous elastic layer and the shaft core member and / or the outer peripheral surface layer. And
The outer peripheral surface layer is composed of a heat-resistant material in which a metal film material or a metal film material is resin-coated,
The heat fixing roller, wherein the shaft core member, the porous elastic layer, and the outer peripheral surface layer are integrated by heat vulcanization of the liquid silicon rubber.

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