JP2006215498A - Fixing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prolong the life time of a fixing roller 11 by minimizing damage to each of the ends of the fixing roller 11 in the case of forming the fixing roller 11 from a thin wall pipe 12 and restricting lengthwise movement of the fixing roller 11. <P>SOLUTION: The opposite face 25a of each of movement restricting rotatory members 25, which is disposed opposite the corresponding end face of the fixing roller 11, is formed to a taper that inclines away from the end face of the fixing roller 11 towards the radial inside of the opposite face 25a. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention belongs to a technical field related to a fixing device used in an image forming apparatus such as a copying machine, a printer, and a FAX.

  Conventionally, as this type of fixing device, a pressure roller, a fixing roller that faces the pressure roller in the radial direction and is pressed in the radial direction by the pressure roller, and heating that heats the fixing roller And a heat roller fixing method having a means is well known, and this is attached to the recording medium while the recording medium is nipped and conveyed between the pressure roller and the fixing roller. The toner image is fixed on the recording medium by heating the toner together with the recording medium.

  In the fixing device of the heat roller fixing system as described above, since the heat capacity of the fixing roller is usually large, there is a problem that the energy efficiency is low and the warm-up time becomes long.

Therefore, for example, as disclosed in Patent Document 1, it has been proposed that the fixing roller is formed of a thin-walled pipe material (cylindrical elastic body) that receives the pressure applied from the pressure roller by an elastic force. In this case, the heat capacity can be made extremely small to shorten the warm-up time, and a uniform and wide nip portion can be formed, so that the toner can be satisfactorily fixed on the recording medium. Has advantages.
JP 2000-347529 A

  By the way, in the above proposed example, both ends of the fixing roller are supported by bearing members having an inner diameter larger than the outer diameter of the fixing roller, and the bearing members are fixed by contacting the end surface of the fixing roller. It also has a role of limiting the movement of the roller in the length direction. This bearing member is designed to rotate around the central axis of the bearing member as the fixing roller rotates when the end surface of the fixing roller abuts, so assuming that the end surface of the fixing roller does not elastically deform, The fixing roller and the bearing member do not slide relative to each other.

  However, the fixing roller is only pressed in the radial direction by the pressure roller only at the intermediate portion in the length direction, but the length of the fixing roller is limited, and usually the end surface of the fixing roller is also rotating. The end face of the fixing roller (end face of the thin pipe material) slides with the bearing member due to elastic deformation. For this reason, the end of the fixing roller is subject to repeated mechanical failure due to elastic deformation (the same applies to the intermediate portion in the longitudinal direction of the fixing roller), and is also subjected to large mechanical stress due to sliding with the bearing member. As a result, when the fixing device is used for a long period of time, there is a problem that the end portion of the fixing roller is broken.

  The present invention has been made in view of such points, and the object of the present invention is to configure the fixing roller with a thin pipe material as described above and limit the movement of the fixing roller in the length direction. In addition, it is intended to extend the life of the fixing roller by suppressing the breakage of the end of the fixing roller (the end of the thin pipe material) as much as possible.

  In order to achieve the above object, according to the first aspect of the present invention, the pressure roller and the pressure roller are opposed to the pressure roller in the radial direction, and are pressed in the radial direction by the pressure roller. A fixing roller made of a thin pipe material received by elastic force, a heating means for heating the fixing roller, and a portion of the outer peripheral surface of the fixing roller opposite to the pressure roller when viewed from the length direction of the fixing roller A fixing roller supporting member having a substantially arc shape so as to cover and supporting the opposite side portion so that the fixing roller is rotatable around the roller axis, and opposed to the end surface of the fixing roller. The end face of the fixing roller is in contact with the opposite face to limit the movement of the fixing roller in the length direction, and at the time of contact, rotates around the central axis as the fixing roller rotates. To support For the fixing device provided with the cylindrical movement-restricting rotating member, the opposed surface of the movement-restricting rotating member is inclined in the direction away from the end surface of the fixing roller toward the inside in the radial direction of the facing surface. It was made to form in a taper shape.

  With the above configuration, the portion on the pressure roller side in the facing direction of the pressure roller and the fixing roller on the end surface of the fixing roller is greatly elastically deformed radially inward by the pressure roller. Since the opposed surface of the movement limited rotation member corresponding to the radially inner side is separated from the end surface of the fixing roller by the taper, the pressure roller side portion does not contact the opposed surface of the movement limited rotation member. As a result, even if the end surface of the fixing roller is elastically deformed, the end surface of the fixing roller only slides on the opposite surface of the movement-restricting rotation member at a portion opposite to the pressure roller. As a result, the sliding between the end surface of the fixing roller and the opposing surface of the movement limiting rotation member is reduced. Therefore, it is possible to effectively suppress the deterioration of the end portion of the fixing roller, and it is possible to suppress the generation of a rubbing sound due to this sliding. In addition, it is possible to suppress the scraping of the facing surface of the movement limiting rotation member. Therefore, the life of the fixing roller and the movement restricting rotating member can be extended.

  The invention according to claim 2 is constituted by a pressure roller, and a thin pipe material which is opposed to the pressure roller in the radial direction, is pressurized in the radial direction by the pressure roller, and receives the applied pressure with an elastic force. The fixing roller, a heating means for heating the fixing roller, and a substantially arc shape so as to cover a portion of the outer peripheral surface of the fixing roller opposite to the pressure roller when viewed from the length direction of the fixing roller. And a fixing roller support member having a support portion for supporting the opposite side portion so that the fixing roller is rotatable about its roller axis, and an annular facing surface facing the end surface of the fixing roller, The end surface of the fixing roller abuts against the opposing surface to restrict the movement of the fixing roller in the length direction, and the cylindrical shape is supported so as to rotate around the central axis as the fixing roller rotates when the contact is made. Movement limit rotation part And the center axis of the movement limiting rotation member passes through the center of the circular arc of the fixing roller support member, and the opposing surface of the movement limitation rotation member is The diameter of the radially inner edge of the facing surface when viewed from the length direction of the fixing roller is D1, and twice the radius of the support portion of the fixing roller support member when viewed from the length direction of the fixing roller is D1. Assume that the thickness of the thin pipe material of the fixing roller is t, and that t ≦ D2−D1 ≦ 10t is satisfied.

  As a result, as the difference between D2 and D1 increases, the contact portion of the end surface of the fixing roller with the opposing surface of the movement-restricting rotation member increases. The portion on the pressure roller side in the facing direction of the pressure roller and the fixing roller at the end surface hardly comes into contact with the facing surface of the movement-restricting rotating member, and is between the end surface of the fixing roller and the facing surface of the movement-limiting rotating member. Sliding is reduced. As the difference between D2 and D1 is smaller, the sliding is surely reduced. However, when the difference is smaller than t, the end surface of the fixing roller is separated from the opposing surface, and the length of the fixing roller is increased. Since there is a possibility that the movement cannot be restricted, it is set to t or more. Therefore, the same effect as that of the invention of claim 1 can be obtained.

  According to a third aspect of the present invention, there is provided a pressure roller, and a thin pipe material that is opposed to the pressure roller in the radial direction, is pressurized in the radial direction by the pressure roller, and receives the applied pressure with an elastic force. The fixing roller, a heating means for heating the fixing roller, and a substantially arc shape so as to cover a portion of the outer peripheral surface of the fixing roller opposite to the pressure roller when viewed from the length direction of the fixing roller. And a fixing roller support member having a support portion for supporting the opposite side portion so that the fixing roller is rotatable about its roller axis, and an annular facing surface facing the end surface of the fixing roller, The end surface of the fixing roller abuts against the opposing surface to restrict the movement of the fixing roller in the length direction, and the cylindrical shape is supported so as to rotate around the central axis as the fixing roller rotates when the contact is made. Movement limit rotation part The movement-restricting rotating member is a movement-restricting rotating member only on a portion of the end surface of the fixing roller opposite to the pressure roller in the facing direction of the pressure roller and the fixing roller. It is assumed that the central axis of the movement-restricting rotating member is supported in an inclined state with respect to the roller axis of the fixing roller so as to abut against the opposite surface.

  As a result, the pressure roller side portion in the facing direction of the pressure roller and the fixing roller on the end surface of the fixing roller does not come into contact with the facing surface of the movement limiting rotation member, and the end surface of the fixing roller and the movement limiting rotation member Sliding between the opposing surfaces is reduced. Therefore, the same effect as that of the invention of claim 1 can be obtained.

  According to a fourth aspect of the present invention, in the first or third aspect of the present invention, the end surface of the fixing roller is formed in a taper shape substantially along the facing surface when the movement-restricting rotating member comes into contact with the facing surface. .

  By doing so, since the end surface of the fixing roller follows the opposing surface of the movement-restricting rotating member, deterioration of the end portion of the fixing roller and scraping of the opposing surface of the movement-limiting rotating member can be further effectively suppressed.

  According to a fifth aspect of the present invention, in any one of the first to third aspects, the end surface of the fixing roller is formed of a sliding member.

  According to the present invention, the sliding member can be made of a material having a small coefficient of friction with the movement-restricted rotating member and slid with the opposing surface of the movement-restricting rotating member. It is possible to achieve a long life.

  According to a sixth aspect of the invention, in the fifth aspect of the invention, the sliding member is formed integrally with the end surface of the fixing roller.

  As a result, the sliding member can be easily provided on the end surface of the fixing roller, and the sliding member can be reliably slid with the opposing surface of the movement limiting rotation member.

  According to a seventh aspect of the present invention, in any one of the first to third aspects of the present invention, the support portion of the fixing roller support member supports the fixing roller via an elastic member.

  As a result, the fixing roller can be uniformly pressed, and the life of the fixing roller can be further extended.

  According to an eighth aspect of the present invention, in the seventh aspect of the invention, the fixing roller support member is a cylindrical member that covers the entire outer periphery of the fixing roller, and a support portion is formed on the inner peripheral surface thereof. And the elastic member has an annular shape whose outer diameter is smaller than the inner diameter of the fixing roller support member and whose inner diameter is larger than the outer diameter of the fixing roller, and the pressure roller and the fixing roller on the outer peripheral surface of the elastic member It is assumed that a portion on the pressure roller side in a direction opposite to is spaced from the inner peripheral surface of the fixing roller support member.

  By doing so, it is possible to suppress the heat of the fixing roller from escaping to the outside via the fixing roller support member, and the heat insulation effect can be enhanced.

  According to a ninth aspect of the present invention, in any one of the first to third aspects, the movement limiting rotation member is configured to be rotatable about an axis extending in a facing direction between the pressure roller and the fixing roller. And

  In other words, the roller shaft of the fixing roller is easily inclined obliquely with respect to the roller shaft of the pressure roller when viewed from the facing direction of the pressure roller and the fixing roller, and when the fixing roller is inclined in this way, the fixing roller support member A thrust force is generated to move the fixing roller in the length direction of the fixing roller, but when the movement restricting rotating member does not rotate about the axis extending in the opposing direction of the pressure roller and the fixing roller, Because of the inclination, the end surface of the fixing roller does not uniformly abut on the facing surface of the movement-restricting rotating member in the moving direction of the recording medium. Cannot be received uniformly in the moving direction. However, in the present invention, the movement restricting rotating member with which the end surface of the fixing roller contacts in the inclined state rotates around the axis extending in the opposing direction of the pressure roller and the fixing roller following the inclination, The end surface of the fixing roller comes into contact with the opposing surface of the movement-restricting rotating member uniformly in the moving direction of the recording medium. As a result, the thrust force generated in the fixing roller can be uniformly received in the moving direction of the recording medium on the opposing surface of the movement limiting rotation member. Therefore, it is possible to more effectively suppress the deterioration of the end portion of the fixing roller and the scraping of the facing surface of the movement limiting rotation member.

  In the invention of claim 10, in the invention of claim 1 or 2, the fixing roller support member is a cylindrical member covering the entire outer periphery of the fixing roller, and a support portion is formed on the inner periphery thereof. In this case, it is assumed that the movement limiting rotation member is integrally formed.

  As a result, the cost of the fixing roller support member and the movement limiting rotation member can be reduced, and the entire fixing device can be downsized.

  According to an eleventh aspect of the present invention, in the tenth aspect of the present invention, the support portion of the fixing roller support member is formed at a position separated by a predetermined distance or more from the facing surface of the movement limiting rotation member.

  As a result, the portion of the end surface of the fixing roller adjacent to the end surface of the fixing roller does not receive a radial force from the support portion of the fixing roller support member, and the damage to the end portion of the fixing roller is made even more effective. Therefore, the life of the fixing roller can be further extended.

  According to a twelfth aspect of the present invention, in the tenth aspect of the present invention, the movement restricting rotation members integrally formed with the fixing roller support member are respectively disposed on both sides in the length direction of the fixing roller, and at least one of the movement restrictions is provided. The rotating member is configured to be rotatable about an axis extending in the opposing direction of the pressure roller and the fixing roller, and is pressed toward the center in the length direction of the fixing roller.

  Thus, as in the ninth aspect of the invention, the thrust force generated in the fixing roller can be received uniformly in the moving direction of the recording medium on the opposed surface of the movement limiting rotation member, and the roller shaft of the fixing roller is Inclination with respect to the roller axis of the pressure roller when viewed from the direction in which the pressure roller and the fixing roller are opposed to each other is suppressed, thereby reducing the thrust force generated in the fixing roller. Therefore, it is possible to more effectively suppress the deterioration of the end portion of the fixing roller and the scraping of the facing surface of the movement limiting rotation member.

  According to a thirteenth aspect of the present invention, in any one of the first to third aspects, the fixing roller support member is configured to be rotatable about an axis extending in the opposing direction of the pressure roller and the fixing roller. And

  That is, the state in which the roller axis of the fixing roller and the central axis of the fixing roller support member are parallel to each other is the most stable state, so that the roller axis of the fixing roller is viewed from the opposing direction of the pressure roller and the fixing roller. In the case where the fixing roller support member is inclined with respect to the roller shaft of the pressure roller, the fixing roller support member rotates about an axis extending in the opposing direction of the pressure roller and the fixing roller, and the fixing roller roller shaft and the fixing roller are fixed. The central axes of the roller support members are parallel to each other. Thereby, the thrust force generated in the fixing roller is reduced and the fixing roller is stabilized. Therefore, it is possible to more effectively suppress the deterioration of the end portion of the fixing roller and the scraping of the facing surface of the movement limiting rotation member.

  According to a fourteenth aspect of the present invention, in the thirteenth aspect of the present invention, the fixing roller supporting member includes a moving direction detecting means for detecting a moving direction of the fixing roller when the fixing roller moves in the length direction of the fixing roller, and a pressure roller. And a rotating means for rotating in the forward and reverse directions within a predetermined angle range about an axis extending in a direction opposite to the fixing roller, the rotating means depending on the moving direction detected by the moving direction detecting means. The fixing roller support member is configured to be rotated in the forward direction or the reverse direction.

  That is, when the roller axis of the fixing roller is inclined with respect to the roller axis of the pressure roller when viewed from the direction in which the pressure roller and the fixing roller face each other, the fixing roller moves in the length direction. When the fixing roller support member is rotated about an axis extending in the opposing direction of the pressure roller and the fixing roller, the inclination of the fixing roller is forcibly changed depending on the rotation direction, and the moving direction of the fixing roller is changed. It can be reversed. Therefore, by selecting the rotation direction of the fixing roller support member according to the moving direction of the fixing roller, the fixing roller can be moved in the direction opposite to the moving direction. It is possible to minimize the movement in the length direction itself, so that the life of the fixing roller and the movement-restricting rotating member can be further extended.

  According to a fifteenth aspect of the invention, in any one of the first to third aspects of the invention, the fixing roller support member is a cylindrical member that covers the entire outer periphery of the fixing roller, and a support portion is provided on the inner peripheral surface thereof. At least one of the above-mentioned fixing roller supports, which is formed corresponding to both ends of the fixing roller and is rotatably supported around the central axis of the fixing roller support member. Drive means for rotating the fixing roller around the roller axis by a frictional force between the support portion of the fixing roller supporting member and the outer peripheral surface of the fixing roller by rotating the member around its central axis is provided. It shall be.

  According to the present invention, stable recording medium feeding can be obtained. That is, when driving the pressure roller, the temperature of the pressure roller is likely to change. For this reason, there is a possibility that the outer diameter of the pressure roller changes and the feed speed of the recording medium changes. When the fixing roller supported by the roller is driven, the outer diameter of the fixing roller hardly changes, so that the recording medium can be reliably fed at a constant speed.

  According to a sixteenth aspect of the invention, in the fifteenth aspect of the invention, the drive means is configured to rotate the fixing roller around the roller axis by rotating one fixing roller supporting member around the central axis. Friction between the support portion of the one fixing roller support member and the outer peripheral surface of the fixing roller, and the friction between the support portion of the other fixing roller support member and the outer peripheral surface of the fixing roller. Assume that the force is small.

  As a result, since the frictional force between the support portion of the one fixing roller support member rotated by the driving means and the outer peripheral surface of the fixing roller is large, the fixing roller is reliably driven to rotate without slipping between them. On the other hand, since the frictional force between the support portion of the other fixing roller support member and the outer peripheral surface of the fixing roller is small, slipping easily occurs between them, and as a result, the roller shaft of the fixing roller is fixed to the pressure roller and the fixing roller. Even when tilted obliquely with respect to the roller axis of the pressure roller when viewed from the direction facing the roller, the thrust force generated in the fixing roller is small, and the fixing roller is less likely to move in the length direction.

  According to a seventeenth aspect of the invention, in the fifteenth aspect of the invention, the driving means is configured to rotate the fixing roller around the roller axis by rotating both the fixing roller support members around the central axis. It shall be.

  This makes it difficult for the roller shaft of the fixing roller to tilt obliquely with respect to the roller shaft of the pressure roller when viewed from the direction in which the pressure roller and the fixing roller face each other. Movement is less likely to occur. Therefore, the life of the fixing roller and the movement restricting rotating member can be further extended.

  According to an eighteenth aspect of the present invention, in the fifteenth aspect of the present invention, the direction of the force applied to the fixing roller support member by the driving means is the opposite direction of the pressure roller and the fixing roller when viewed from the length direction of the fixing roller. It is assumed that the fixing roller is pressed against the pressure roller or inclined within 30 ° with respect to the direction.

  By doing so, the parallelism between the central axis of the fixing roller support member and the roller axis of the fixing roller is stably maintained, and it is difficult for the fixing roller to move in the length direction.

  According to a nineteenth aspect of the present invention, in the fifteenth aspect of the present invention, the driving means includes a driving pulley and a belt stretched between the driving pulley and the outer peripheral surface of the fixing roller support member. It is assumed that the fixing roller support member is rotated about its central axis by the driving pulley and the belt.

  As a result, the load fluctuation is smaller than when the fixing roller support member is rotated by the gear, and slippage hardly occurs between the support portion of the fixing roller support member and the outer peripheral surface of the fixing roller. Further, in the case of gears, the fixing roller support member easily vibrates due to load fluctuations, and this vibration fluctuates the pressure applied by the pressure roller, causing excessive pressure to act on the fixing roller. There is a possibility that the life of the fixing roller may be shortened. However, in the case of a belt, since the load fluctuation is small, no excessive pressure is applied to the fixing roller, so that the life of the fixing roller can be extended. Can be planned.

  According to a twentieth aspect of the present invention, in any one of the first to third aspects of the present invention, the fixing roller supporting member is disposed corresponding to both ends of the fixing roller, and the thin pipe material of the fixing roller is It is assumed that the outer peripheral surface and the inner peripheral surface of at least both ends of the thin pipe material are made of metal and subjected to shot peening treatment.

  Thus, the shot peening process can apply residual compressive stress to both ends of the fixing roller which is easily broken, thereby improving the repeated fatigue strength against expansion and contraction, and thus the life of the fixing roller can be extended. . Here, for the shot peening process on the inner peripheral surface of the thin pipe material, a special device is required to process the central part in the length direction, but to process the end part, No special equipment is required, and it can be performed with a normal device similar to the processing of the outer peripheral surface, so if the shot peening process is performed only on the outer peripheral surface and the inner peripheral surface of both ends of the thin pipe material, Easy and low cost. On the other hand, even if the treatment is performed only at both ends, there is no problem because it is particularly easy to destroy both ends.

  According to a twenty-first aspect of the present invention, in the invention according to any one of the first to third aspects, the fixing roller support members are respectively disposed corresponding to both ends of the fixing roller, and in the thin pipe material of the fixing roller, It is assumed that a rubber layer is formed on the entire outer peripheral surface excluding both ends.

  By doing so, it is possible to realize stable fixing and feeding of the recording medium, and at the both ends corresponding to the support portion of the fixing roller support member, no rubber layer is formed, so that the fixing roller It is possible to maintain a stable contact between the outer peripheral surface of the fixing roller and the support portion of the fixing roller support member.

  According to a twenty-second aspect of the present invention, in the invention according to any one of the first to third aspects, the pressure roller is formed of a thin pipe material that receives a reaction force of a pressure applied to the fixing roller with an elastic force.

  According to the present invention, the nip portion that is the contact portion between the fixing roller and the pressure roller has a substantially flat shape, and various recording media can be conveyed without wrinkles.

  According to a twenty-third aspect of the present invention, in any one of the first to third aspects of the present invention, a rotation detection unit that detects rotation of the fixing roller is provided, and the rotation detection unit rotates only a part of the circumferential direction of the fixing roller once. It is assumed that the rotation of the fixing roller is detected by detecting each time.

  As a result, the rotation speed of the fixing roller can be controlled to rotate the fixing roller at a constant rotation speed, and the rotation of the fixing roller can be detected at low cost. On the other hand, even if only a part of the fixing roller in the circumferential direction is detected every rotation, the rotation speed of the fixing roller can be sufficiently controlled as long as it is a normal recording medium conveyance speed.

  According to a twenty-fourth aspect of the present invention, in any one of the first to third aspects, the pressure roller is configured to press the fixing roller in a radial direction by being pressed against the fixing roller by a pressing member. It is assumed that a limiting member that limits the pressing amount of the pressing roller to the fixing roller by the pressing member is provided.

  That is, when a crack or the like occurs at the end of the fixing roller, the pressing amount of the pressure roller to the fixing roller usually increases, and the crack progresses and breaks immediately. However, in this invention, since the pressing amount is limited by the limiting member, it is possible to prevent the occurrence of a major trouble by suppressing the progress of the fixing roller end portion to breakage.

  According to a twenty-fifth aspect of the present invention, in any one of the first to third aspects, the pressure roller is configured to press the fixing roller in a radial direction by being pressed against the fixing roller by a pressing member. A pressing amount detecting means for detecting the pressing amount of the pressing roller to the fixing roller by the pressing member is provided, and configured to detect the deterioration of the fixing roller based on the pressing amount detected by the pressing amount detecting means. It shall be.

  In this way, when a crack or the like occurs at the end of the fixing roller (thin pipe material), the pressing amount of the pressure roller against the fixing roller increases, and this increase in pressing amount is detected by the pressing amount detecting means. By this detection, the deterioration of the fixing roller can be detected. When the deterioration of the fixing roller is detected, the pressing of the pressure roller to the fixing roller is released, or the operation of the image forming apparatus is stopped to prevent a major trouble from occurring. It is possible to notify the user that the fixing device has failed.

  As described above, according to the fixing device of the present invention, since the sliding between the end surface of the fixing roller and the facing surface of the movement limiting rotation member is reduced, the end of the fixing roller is deteriorated. Can be effectively suppressed, and the facing surface of the movement-restricting rotating member can be prevented from being scraped, so that the life of the fixing roller can be extended.

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

(Embodiment 1)
FIG. 1 shows a fixing device according to Embodiment 1 of the present invention. This fixing device is used in an image forming apparatus such as a copying machine, a printer, or a FAX, and removes toner adhering to a recording medium such as recording paper. This is a heat roller fixing system in which a toner image is fixed on a recording medium by heating together with the recording medium.

  The fixing device includes a pressure roller 1 and a fixing roller 11 that faces the pressure roller 1 in the radial direction (vertical direction in the present embodiment). The pressure roller 1 includes, for example, an aluminum cylindrical base material 2 having a diameter of 20 mm, and a silicone sponge having a thickness of 7 mm that covers the entire outer peripheral surface of the base material 2 over the entire length direction in close contact. The rubber 3 is composed of a Teflon tube (not shown) having a thickness of 30 μm that covers the entire outer circumferential surface of the silicone sponge rubber 3 in a close contact state over substantially the entire length direction.

  As shown in FIG. 2, the pressure roller 1 is pressed against the fixing roller 11 by a pressing member 5 extending in a substantially horizontal direction. That is, both end portions 2a having a small diameter of the base material 2 are respectively rotatably fitted in fitting holes 5a formed at intermediate portions in the length direction of the pressing members 5 provided corresponding to the both end portions 2a. One end portion of each pressing member 5 is rotatably supported around the rotation shaft 5 b, and the other end portion is urged toward the fixing roller 11 (upper side) by a tension coil spring 6. Accordingly, each pressing member 5 tends to rotate counterclockwise in FIG. 2 around the rotation shaft 5b, and therefore the pressure roller 1 is pressed against the fixing roller 11 so as to move upward. By this pressing, the pressure roller 1 presses the fixing roller 11 in the radial direction with a predetermined pressure. In this embodiment, this applied pressure is about 9.3 N / cm.

  Further, the pressure roller 1 has both end portions 2a of the base material 2 rotatably fitted in the fitting holes 5a of the pressing members 5, respectively. It can rotate around the axis X1 (the central axis of the base material 2). Then, a driven gear 8 that meshes with a drive gear 7 that is rotationally driven by a motor or the like (not shown) via a connecting shaft 7a is coupled to one end portion 2a (left end portion in FIG. 1) of the base material 2. The pressure roller 1 is rotationally driven around the roller axis X1 by the drive gear 7 and the driven gear 8.

  The fixing roller 11 is composed of a thin pipe material 12 that receives the pressure applied by the pressure roller 1 with an elastic force. That is, the thin-walled pipe material 12 is made of a metal having a spring property such as stainless steel or phosphor bronze, and is elastically deformed by the applied pressure and has a circular cross section, so that the pressure roller 1 and the fixing roller 11 are opposed to each other. The shape (vertical direction) is a short axis and the horizontal direction is a long axis. In the present embodiment, the thin pipe material 12 uses stainless steel (SUS304) having an outer diameter of 34 mm and a wall thickness of 0.2 mm. Shot peening is performed on the outer peripheral surface and inner peripheral surface of both ends (including portions supported by a fixing roller support member 21 described later) of the thin-walled pipe material 12. The shot peening treatment is performed not only on the outer peripheral surface and the inner peripheral surface of both ends of the thin pipe member 12 but also on the outer periphery of the intermediate portion in the length direction of the thin pipe member 12 (the length direction of the fixing roller 11). You may make it give to a surface and an internal peripheral surface. However, when performing shot peening on the inner peripheral surface of the thin pipe material 12 in the longitudinal direction, a special device is required, so that shot peening is applied only to the outer peripheral surface and the inner peripheral surface of both ends. It is easier and less expensive to do. On the other hand, even if the treatment is performed only at both ends, there is no problem because it is particularly easy to destroy both ends.

  A rubber layer 13 is formed on the entire circumference of the thin pipe material 12 except for both ends. In the present embodiment, the rubber layer 13 is made of silicone rubber having a thickness of 200 μm, and the outer peripheral surface of the rubber layer 13 is covered with a Teflon tube 14 having a thickness of 30 μm in close contact with the entire length direction. (The rubber layer 13 and the Teflon tube 14 are very small in thickness, and are not shown in drawings other than FIG. 1 among the drawings showing the fixing roller 11). The pressure roller 1 applies pressure to the portion of the fixing roller 11 where the rubber layer 12 is formed, and the rubber layer 12 of the fixing roller 11 is driven by the rotation of the pressure roller 1. The recording medium is nipped and conveyed between the portion where the toner is formed and the pressure roller 1 (nip portion). When the pressure roller 1 is driven to rotate, the fixing roller 11 rotates around the roller axis X2 of the fixing roller 11 (the central axis of the elastically deformed thin pipe material 12) via the pressure roller 1 or the recording medium in the nip portion. It will be driven and rotated.

  Inside the thin pipe member 12, a halogen lamp 17 is disposed as a heating means for heating the fixing roller 11 in order to heat the toner on the recording medium together with the recording medium. 11 is heated to about 170 ° C. Such a heating means is not limited to the halogen lamp 17 and may be other lamps or electromagnetic induction. Further, when a lamp is used, the lamp may be provided outside the thin pipe material 12.

  Fixing roller support members 21 are disposed at positions corresponding to both ends of the fixing roller 11. Each fixing roller support member 21 is a portion (upper portion) opposite to the pressure roller 1 on the outer peripheral surface of the fixing roller 11 (that is, the outer peripheral surface of the thin pipe material 12) when viewed from the length direction of the fixing roller 11. And a support portion 21a for supporting the opposite portion (upper portion) so that the fixing roller 11 can rotate about its roller axis X2. The radius of the support portion 21a is larger than the radius of the thin pipe material 12 before elastic deformation. When the fixing roller 11 is pressed upward from the lower side by the pressure roller 1, a portion of the outer peripheral surface of the fixing roller 11 facing the support portion 21 a is in contact with and supported by the support portion 21 a. The thin pipe member 12 is elastically deformed, and at this time, as shown in FIG. 2, the upper portion of the thin pipe member 12 is substantially along the support portion 21a. Each of the fixing roller support members 21 is provided at a portion of the end portion of the fixing roller 11 that is separated from the end surface of the fixing roller 11 by a predetermined distance or more, and a portion close to the end surface of the fixing roller 11 is supported by the fixing roller. The radial direction force is not received from the support portion 21 a of the member 21.

  Each of the fixing roller support members 21 is a cylindrical member that covers the entire outer periphery of the fixing roller 11 and has a support portion 21a formed on the inner periphery thereof. The center axis of each fixing roller support member 21 a is parallel to the roller axis X <b> 2 of the fixing roller 11. Each fixing roller support member 21 is supported by a bearing 22 so as to be rotatable about its central axis, and rotates around the central axis of the fixing roller support member 21 as the fixing roller 11 rotates. Yes. Thus, even if the fixing roller support member 21 rotates, the support portion 21a is always on the upper portion of the fixing roller support member 21. Therefore, the inner peripheral surface of the fixing roller support member 21 has a circular shape when viewed from the length direction of the fixing roller 11 so that it can serve as a support portion 21a at any rotational position.

  The fixing roller support member 21 is not necessarily supported so as to be rotatable around its central axis, and may be fixed. In this case, the fixing roller support member 21 has a semicircular shape having only an upper half when viewed from the length direction of the fixing roller 11 (such as a pressure roller support member 4 described later shown in FIG. ). However, it is preferable that the fixing roller support member 21 is rotatably supported because the sliding with the fixing roller 11 hardly occurs.

  In the present embodiment, the rubber layer 13 is not formed on the outer peripheral surface of the fixing roller 11 corresponding to the fixing roller support member 21 so that the thin pipe material 12 directly contacts the support portion 21a. However, if the fixing roller support member 21 is supported so as to be rotatable about its central axis, the rubber layer 13 may also be formed on the portion corresponding to the fixing roller support member 21. However, without the rubber layer 13, there is no need to consider deterioration of the rubber and the like, and stable contact between the outer peripheral surface of the fixing roller 11 and the support portion 21 a of the fixing roller support member 21 is maintained.

  In this embodiment, the fixing roller support member 21 is made of a resin having an inner diameter of 43 mm and a width (a length along the length direction of the fixing roller 11) of 8 mm. As a material for the fixing roller support member 21, bakelite or PPS (polyphenylene sulfide) having good heat resistance is preferable.

  On both sides of the fixing roller 11 in the length direction, cylindrical movement limiting rotation members 25 are respectively disposed. Each of the movement limiting rotation members 25 has an annular facing surface 25a facing the end surface of the fixing roller 11 (that is, the end surface of the thin pipe material 12) extending in a direction perpendicular to the roller axis X2 of the fixing roller 11. The movement of the fixing roller 11 in the length direction is restricted by the end surface of the fixing roller 11 coming into contact with the facing surface 25a. The central axis of each movement limiting rotation member 25 is parallel to the roller axis X2 of the fixing roller 11 and coincides with the central axis of the fixing roller support member 21 (the arc shape of the fixing roller support member 21). It passes through the circle center of the support portion 21a). Each movement limiting rotation member 25 is supported by a bearing 26 so as to rotate around the central axis of the movement limiting rotation member 25 as the fixing roller 11 rotates when the end face of the fixing roller 11 contacts. . The distance between the two movement limiting rotation members 25 is slightly larger than the length of the fixing roller 11 in a state where it is lengthened by heating, and the movement of the fixing roller 11 in the length direction is the same. It is restricted between the movement restricting rotating members 25.

  As shown in FIG. 3, the opposing surface 25a of each of the movement limiting rotation members 25 is formed in a tapered shape that inclines in the direction away from the end surface of the fixing roller toward the radially inner side of the opposing surface 25a. . The inclination angle θ (θ = (180 ° −taper angle) / 2) of the facing surface 25a with respect to the plane perpendicular to the central axis of the movement-restricted rotating member 25 is preferably 2 ° to 15 °, and more preferably 5 ° to 9 °. In this embodiment, it is set to 7 °. As the material of each movement restricting rotation member 25, bakelite or PPS (polyphenylene sulfide) having good heat resistance is preferable, like the fixing roller support member 21.

  A portion within a predetermined distance from the end surface of the fixing roller 11 (a portion close to the end surface of the fixing roller 11) on the outer peripheral surface of one end portion (right end portion in FIG. 1) of the fixing roller 11 (thin pipe member 12) is shown in FIG. As shown in FIG. 4, the first density pattern 11a is formed in which the density in one part in the circumferential direction is low and the density in the other part is high. The low density portion of the first density pattern 11 a is detected by the first photosensor 30 every rotation of the fixing roller 11. That is, the first photosensor 30 is configured by a reflection type optical sensor that detects the amount of reflected light of the projected light, and detects the amount of reflected light of the light projected on the first density pattern 11a. Thus, a portion with a low density (the amount of reflected light increases) is detected. Thus, the first photosensor 30 constitutes a rotation detecting means for detecting the rotation of the fixing roller 11 by detecting only a part of the fixing roller in the circumferential direction for each rotation. By detecting the rotation of the fixing roller 11 in this way, the motor for rotating the pressure roller 1 is controlled to control the rotation speed of the fixing roller 11 to be a constant speed. In this embodiment, the rotation speed of the fixing roller 11 is controlled to about 0.94 rotation / s so that the recording medium conveyance speed is about 100 mm / s. With such a rotation speed, the rotation speed of the fixing roller 11 can be sufficiently controlled even if only a part of the fixing roller 11 in the circumferential direction is detected every rotation. The position of the first density pattern 11 a may be any position in the length direction of the fixing roller 11.

  In the fixing device having the above-described configuration, when the fixing roller 11 moves in the length direction, the end surface of the fixing roller 11 (the end surface of the thin-walled pipe material 12) comes into contact with the opposing surface 25a of the movement limiting rotation member 25. Thus, the movement of the fixing roller 11 in the length direction is restricted. The movement limiting rotation member 25 with which the end surface of the fixing roller 11 abuts rotates about the central axis of the movement limiting rotation member 25 as the fixing roller 11 rotates about the roller axis X2. Since the end surface is elastically deformed while rotating, sliding occurs between the end surface of the fixing roller 11 and the facing surface 25a of the movement limiting rotation member 25. However, since the opposing surface 25a of the movement restricting rotation member 25 is formed in a tapered shape as described above, such sliding can be reduced. That is, the pressure roller 1 side portion (lower side portion) in the facing direction of the pressure roller 1 and the fixing roller 11 on the end surface of the fixing roller 11 is radially inward of the fixing roller 11 by the pressure applied by the pressure roller 1. Although it is elastically deformed greatly (upper side), the opposing surface 25a of the movement limiting rotation member 25 corresponding to the radially inner side is separated from the end surface of the fixing roller 11 by the taper. The portion does not come into contact with the opposed surface of the movement-restricting rotation member (see the relationship between the fixing roller 11 and the movement-restricting rotation member 25 indicated by a two-dot chain line in FIG. 2). As a result, even if the end surface of the fixing roller 11 is elastically deformed, the end surface of the fixing roller 11 only slides with the facing surface 25a of the movement limiting rotation member 25 at a portion (upper portion) opposite to the pressure roller 1. As a result, the sliding between the end surface of the fixing roller 11 and the facing surface 25a of the movement limiting rotation member 25 is reduced. Therefore, it is possible to effectively suppress the deterioration of the end portion of the fixing roller 11 and to suppress the generation of a rubbing sound due to this sliding. Further, it is possible to suppress the scraping of the facing surface 25a of the movement limiting rotation member 25. Therefore, the life of the fixing roller 11 and the movement restricting rotating member 25 can be extended.

  In the present embodiment, the pressure roller 1 is rotationally driven. Instead of this, by rotating the fixing roller support member 21 around its central axis as in the twelfth embodiment described later, The fixing roller 11 may be driven to rotate about the roller axis X2 by a frictional force between the support portion 21a of the fixing roller support member 21 and the outer peripheral surface of the fixing roller 11.

(Embodiment 2)
FIG. 5 shows a second embodiment of the present invention, in which the shape of the facing surface 25a of the movement limiting rotation member 25 is different from that of the first embodiment, and other configurations are the same as those of the first embodiment. . The description of the same configuration as that of the first embodiment is omitted.

Specifically, the facing surface 25a of the movement limiting rotation member 25 is not formed in a tapered shape as in the first embodiment, and the central axis of the movement limiting rotation member 25 (or the roller axis X2 of the fixing roller 11). It extends in the direction perpendicular to. The opposed surface 25a of the movement limiting rotation member 25 is viewed from the length direction of the fixing roller 11 with the diameter of the radially inner edge of the facing surface 25a when viewed from the length direction of the fixing roller 11 being D1. When the radius of the support portion 21a of the fixing roller support member 21 at that time (inner diameter of the fixing roller support member 21) is D2, and the thickness of the thin pipe member 12 of the fixing roller 11 is t,
t ≦ D2-D1 ≦ 10t
It is formed to satisfy.

  That is, as the difference between D2 and D1 increases, the contact portion of the end surface of the fixing roller 11 with the facing surface 25a of the movement-restricting rotation member 25 increases. If the difference is 10 t or less, the fixing roller 11, the pressure roller 1 side portion (lower portion) in the facing direction of the pressure roller 1 and the fixing roller 11 hardly comes into contact with the facing surface 25a of the movement restricting rotation member 25. Sliding between the end surface and the facing surface 25a of the movement limiting rotation member 25 is reduced. As the difference between D2 and D1 is smaller, the sliding is surely reduced. However, when the difference is smaller than t, the end surface of the fixing roller 11 is separated from the facing surface 25a, and the length of the fixing roller 11 is increased. Since there is a possibility that the movement in the vertical direction cannot be restricted, it is set to t or more.

  Accordingly, also in the second embodiment, similarly to the first embodiment, the sliding between the end surface of the fixing roller 11 and the facing surface 25a of the movement restricting rotation member 25 is reduced. As a result, the fixing roller 25 and the movement are reduced. The life of the limiting rotation member 25a can be extended.

(Embodiment 3)
FIG. 6 shows Embodiment 3 of the present invention, in which the central axis (X3 shown in FIG. 6) of the movement restricting rotation member 25 is inclined with respect to the roller axis X2 of the fixing roller 11.

  That is, in the present embodiment, the opposed surface 25a of the movement restricting rotation member 25 is not formed in a tapered shape as in the first embodiment, but extends in a direction perpendicular to the central axis X3 of the movement restricting rotation member 25. Yes. However, the central axis X3 of the movement limiting rotation member 25 is inclined with respect to the roller axis X2 of the fixing roller 11 so that the upper portion of the facing surface 25a approaches the end surface of the fixing roller 11, and thereby the facing surface 25a. Is in the same state as the taper shape. In other words, the movement restricting rotation member 25 has only a portion (upper portion) opposite to the pressure roller 1 in the facing direction of the pressure roller 1 and the fixing roller 11 on the end surface of the fixing roller 11. Thus, the central axis X3 of the movement restricting rotation member 25 is supported in an inclined state with respect to the roller axis X3 of the fixing roller 11 so as to abut against the opposite surface 25a.

  Accordingly, also in the third embodiment, similarly to the first embodiment, the lower part of the end surface of the fixing roller 11 does not come into contact with the facing surface 25a of the movement limiting rotation member 25, and the movement restriction with the end surface of the fixing roller 11 is achieved. Sliding between the rotating member 25 and the facing surface 25a is reduced, and thus the life of the fixing roller 25 and the movement restricting rotating member 25a can be extended.

(Embodiment 4)
FIG. 7 shows a fourth embodiment of the present invention, in which the shape of the end surface of the fixing roller 11 is changed in the first embodiment.

  That is, in the fourth embodiment, the end surface of the fixing roller 11 is formed in a taper shape substantially along the facing surface 25a when the movement restricting rotating member 25 contacts the facing surface 25a. As a result, the end surface of the fixing roller 11 follows the facing surface 25a of the movement-restricting rotating member 25, so that deterioration of the end portion of the fixing roller 11 and scraping of the facing surface 25a of the moving-restricting rotating member 25 are further effectively suppressed. be able to.

  In the fourth embodiment, the movement limiting rotation member 25 is the one in the first embodiment, but the central axis X3 of the movement limiting rotation member 25 is inclined with respect to the roller axis X2 of the fixing roller 11 as in the third embodiment. Even in this case, the configuration of the fourth embodiment can be applied.

(Embodiment 5)
FIG. 8 shows a fifth embodiment of the present invention, in which the end surface of the fixing roller 11 is constituted by a sliding member 15 and other configurations are the same as those of the first embodiment.

  The sliding member 15 includes a circular base portion 15a in which a through-hole having substantially the same diameter as the inner diameter of the thin pipe member 12 is formed in the center portion, and a cylindrical side portion 15b provided on the outer peripheral edge portion of the base portion 15a. And is covered with the end surface of the fixing roller 11. The inner diameter of the side portion 15b may be substantially the same as the outer diameter of the thin pipe material 12 before elastic deformation, or may be slightly larger. Further, the sliding member 15 may be fixed to the end face of the fixing roller 11 or may not be fixed. When not fixed, a rubber layer or the like is formed on the surface of the sliding member 15 on the side of the fixing roller 11 so as to increase the friction coefficient so that the sliding member 15 and the fixing roller 11 do not slide. Alternatively, as shown in FIG. 9, the sliding member 15 may be integrally formed on the end surface of the fixing roller 11 using a mold. In this case, finishing may be performed after molding.

  As a material of the sliding member 15, PPS or the like is preferable. Such a sliding member 15 can reduce the friction coefficient between the end surface of the fixing roller 11 and the facing surface 25a of the movement-restricting rotating member 25 as much as possible. It is possible to achieve a long life.

  Since the first density pattern 11a cannot be provided at the same location as in the first embodiment, it may be provided at another location. Further, when the sliding member 15 is fixed to the end surface of the fixing roller 11, the sliding member 15 may be provided on the side portion 15 b of the sliding member 15.

  Furthermore, the movement restricting rotation member 25 is not limited to the one in the first embodiment, and the one in the second or third embodiment may be used.

(Embodiment 6)
FIG. 10 shows Embodiment 6 of the present invention, in which the support portion 21 a of the fixing roller support member 21 supports the fixing roller 11 via the elastic member 23.

  That is, in the sixth embodiment, an annular elastic member 23 having the same width as that of the fixing roller support member 21 is fitted on the inner peripheral surface of the fixing roller support member 21. The thickness of the elastic member 23 is preferably 0.5 mm to 3 mm, and is 1.5 mm in this embodiment. Examples of the material of the elastic member 23 include polyurethane rubber and chloroprene rubber.

  By interposing such an elastic member 23 between the outer peripheral surface of the fixing roller 11 (thin pipe member 12) and the support portion 21a of the fixing roller support member 21, the fixing roller 11 can be uniformly pressurized. Further, the life of the fixing roller 11 can be further extended.

  In the sixth embodiment, the outer diameter of the elastic member 23 is substantially the same as the inner diameter of the fixing roller support member 21, and the outer peripheral surface of the elastic member 23 is the same as the inner peripheral surface of the fixing roller support member 21 over the entire circumference. As shown in FIG. 11, the outer diameter of the elastic member 23 is made smaller than the inner diameter of the fixing roller support member 21 and the inner diameter of the elastic member 23 is made larger than the outer diameter of the fixing roller 11 as shown in FIG. On the outer peripheral surface of the elastic member 23, the pressure roller 1 side portion (lower side portion) in the facing direction of the pressure roller 1 and the fixing roller 11 may be separated from the inner peripheral surface of the fixing roller support member 21. Good. By doing so, it is possible to suppress the heat of the fixing roller 11 from escaping to the outside via the fixing roller support member 21 and to enhance the heat insulation effect.

  Moreover, any structure of the said Embodiment 1-5 can be employ | adopted for the movement limitation rotation member 25 and other structures.

(Embodiment 7)
FIG. 12 shows a seventh embodiment of the present invention, in which the movement restricting rotation member 25 is configured to be rotatable about a shaft 25b extending in the opposing direction of the pressure roller 1 and the fixing roller 11, and the other configurations are described above. This is similar to the first embodiment. It is preferable that the axis of the shaft 25b intersects with the central axis of the movement limiting rotation member 25.

  The reason for this configuration is as follows. That is, as shown in FIG. 12, the roller axis X2 of the fixing roller 11 is easily inclined obliquely with respect to the roller axis X1 of the pressure roller 1 when viewed from the facing direction of the pressure roller 1 and the fixing roller 11. When the fixing roller 11 is tilted in this way, a thrust force is generated to move the fixing roller 11 in the length direction in relation to the tilting with respect to the fixing roller support member 21, but the movement limiting rotation member 25 is rotated around the shaft 25 b. In the case where the rotation is not performed, the end surface of the fixing roller 11 does not uniformly contact the opposing surface 25a of the movement restricting rotation member 25 in the moving direction of the recording medium due to the above inclination. The opposed surface 25a of the movement limiting rotation member 25 cannot be received uniformly in the moving direction of the recording medium. Therefore, by configuring the movement limiting rotation member 25 so as to be rotatable around the shaft 25b, the movement limiting rotation member 25 with which the end surface of the fixing roller 11 contacts in the tilted state follows the shaft 25b. By rotating around, the end surface of the fixing roller 11 comes into contact with the opposing surface 25a of the movement limiting rotation member 25 uniformly in the moving direction of the recording medium. As a result, the thrust force generated in the fixing roller 11 can be received uniformly in the moving direction of the recording medium by the facing surface 25a of the movement limiting rotation member 25. Therefore, the deterioration of the end portion of the fixing roller 11 and the scraping of the facing surface 25a of the movement restricting rotating member 25 can be further effectively suppressed.

  In the seventh embodiment, the movement restricting rotation member 25 is the one in the first embodiment, but the present invention can also be applied to the second and third embodiments. Even in the case of application to the third embodiment, the movement limiting rotation member 25 may be configured to be rotatable about an axis extending in the opposing direction of the pressure roller 1 and the fixing roller 11.

(Embodiment 8)
FIG. 13 shows an eighth embodiment of the present invention, in which the fixing roller support member 21 is integrally formed with the movement restricting rotation member 25, and other configurations are the same as those of the first embodiment.

  That is, in the present embodiment, the fixing roller support member 21 is cylindrical as in the first embodiment, and the surface on the movement limiting rotation member 25 side is radially outward of the facing surface 25a of the movement limiting rotation member 25. Connected to the part. As a result, there is no bearing 22 for supporting the fixing roller support member 21, and the bearing 26 allows the fixing roller support member 21 and the movement limiting rotation member 25 to be connected to the central axis of the movement limiting rotation member 25 (the central axis of the fixing roller support member 21. It is also supported so that it can rotate integrally.

  Thus, by integrally forming the fixing roller support member 21 on the movement limiting rotation member 25, it is possible to reduce the cost of the fixing roller support member 21 and the movement limitation rotation member 25 and to reduce the size of the entire fixing device. be able to.

  In the eighth embodiment, the facing surface 25a of the movement limiting rotation member 25 is formed in a tapered shape as in the first embodiment, but may be as in the second embodiment.

  In the eighth embodiment, the support portion 21a of the fixing roller support member 21 is in contact with the facing surface 25a of the movement limiting rotation member 25. However, as shown in FIG. It may be formed at a position separated from the 25 opposing surfaces 25a by a predetermined distance or more (that is, a position similar to the fixing roller support member 21 of the first embodiment). In this way, the portion of the end portion of the fixing roller 11 that is close to the end surface of the fixing roller 11 does not receive radial force from the support portion 21a of the fixing roller support member 21, and the end portion of the fixing roller 11 is damaged. Can be more effectively suppressed.

  Further, in the eighth embodiment, the pressure roller 1 is rotationally driven, but instead, the fixing roller support member 21 is rotated around its central axis as in a twelfth embodiment described later. The fixing roller 11 may be rotationally driven around the roller axis X2 by a frictional force between the support portion 21a of the fixing roller support member 21 and the outer peripheral surface of the fixing roller 11.

(Embodiment 9)
FIG. 15 shows a ninth embodiment of the present invention, in which the movement restricting rotating member 25 integrally formed with the fixing roller support member 21 in the eighth embodiment is pressed toward the center in the length direction of the fixing roller 11. It is a thing.

  That is, in the ninth embodiment, a support member 41 that supports one movement-restricting rotation member 25 so as to be rotatable about a shaft 25b extending in the opposing direction of the pressure roller 1 and the fixing roller 11 is provided. The support member 41 is pivotally supported around a shaft 41 a extending in the opposing direction of the pressure roller 1 and the fixing roller 11 on the radially outer side of the movement limiting rotation member 25. It is preferable that the axis of the shaft 25b intersects with the central axis of the movement restricting rotation member 25 as in the seventh embodiment.

  The tip of the support member 41 is urged toward the center in the length direction of the fixing roller 11 by a tension coil spring 42. As a result, the support member 41 tries to rotate in the counterclockwise direction in FIG. 15 around the shaft 41a. As a result, the movement limiting rotation member 25 is pressed toward the center in the length direction of the fixing roller 11. Become. It should be noted that any configuration may be used for pressing the movement limiting rotation member 25 toward the center in the length direction of the fixing roller 11.

  With such a configuration, the fixing roller 11 is stabilized in a state in which both end surfaces thereof are simultaneously in contact with the opposing surfaces 25a of the both movement limiting rotation members 25, respectively. At this time, as in the seventh embodiment, both end surfaces of the fixing roller 11 are in contact with the opposing surfaces 25a of the both movement restricting rotating members 25 uniformly in the moving direction of the recording medium. In addition, the roller axis X2 of the fixing roller 11 is prevented from being inclined obliquely with respect to the roller axis X1 of the pressure roller 1 when viewed from the direction in which the pressure roller 1 and the fixing roller 11 face each other. The thrust force generated in the roller 11 can be reduced. Therefore, it is possible to more effectively suppress the deterioration of the end portion of the fixing roller 11 and the scraping of the facing surface 25a of the movement limiting rotation member 25.

  In the ninth embodiment, only one movement limiting rotation member 25 is pressed toward the center in the length direction of the fixing roller 11, but both movement limiting rotation members 25 are pressed in the length direction of the fixing roller 11. You may make it press to the center side.

(Embodiment 10)
FIG. 16 shows Embodiment 10 of the present invention, in which the fixing roller support member 21 is configured to be rotatable around a shaft 45 a extending in the opposing direction of the pressure roller 1 and the fixing roller 11. In this embodiment, since the fixing roller support member 21 is integrally formed with the movement restricting rotation member 25 as in the eighth and ninth embodiments, the fixing roller support member 21 is interposed via the movement restricting rotation member 25. Thus, it can be rotated around the shaft 45a.

  That is, in this embodiment, one movement restricting rotation member 25 is supported and fixed by the support member 45 (it does not rotate with respect to the support member 45). On the outer side in the radial direction, the pressure roller 1 and the fixing roller 11 are rotatably supported around a shaft 45a extending in the facing direction. For this reason, the fixing roller support member 21 can be rotated around the shaft 45 a together with the movement limiting rotation member 25. The support member 45 is not biased by a spring as in the ninth embodiment.

  With this configuration, when the roller axis X2 of the fixing roller 11 is inclined with respect to the roller axis X1 of the pressure roller 1 when viewed from the direction in which the pressure roller 1 and the fixing roller 11 face each other. The fixing roller support member 21 rotates about the shaft 45a, so that the roller axis X2 of the fixing roller 11 and the central axis of the fixing roller support member 21 are parallel to each other. That is, since the state where the roller axis X2 of the fixing roller 11 and the central axis of the fixing roller support member 21 are parallel to each other is the most stable state, such a state is automatically obtained. Thereby, the thrust force generated in the fixing roller 11 is reduced and the fixing roller 11 is stabilized. Therefore, it is possible to more effectively suppress the deterioration of the end portion of the fixing roller 11 and the scraping of the facing surface 25a of the movement limiting rotation member 25.

  In the tenth embodiment, only one fixing roller support member 21 (and the movement restricting rotation member 25) is configured to be rotatable. However, both the fixing roller support members 21 may be configured to be rotatable. .

  In addition, the fixing roller support member 21 may be a separate member from the movement restricting rotation member 25 as in the first embodiment. In this case, the fixing roller support member 21 is used as the pressure roller 1 and the fixing roller. What is necessary is just to comprise so that it can rotate around the axis | shaft extended in the opposing direction with 11. FIG. If the fixing roller support member 21 and the movement restricting rotating member 25 are separate bodies, the movement restricting rotating member 25 may be any one of the first to third embodiments.

  Further, the rotation shaft 45a of the support member 45 may be located at any position, and is appropriately set depending on how much the roller shaft X2 of the fixing roller 11 is inclined with respect to the roller shaft X1 of the pressure roller 1. That's fine. For example, as shown in FIG. 17, the shaft 45 a may be provided at a position where the axis of the shaft 45 a intersects the central axis of the movement restricting rotating member 25.

(Embodiment 11)
FIG. 18 shows Embodiment 11 of the present invention, in which the moving direction of the fixing roller 11 is detected, and the fixing roller 11 is moved in the direction opposite to the moving direction.

  That is, in the eleventh embodiment, a support member 45 similar to the modification of the tenth embodiment (FIG. 17) (may be the same support member 45 as FIG. 16) is provided. A cylinder 46 and a tension coil spring 47 that rotate the shaft 45a around a shaft 45a within a predetermined angle range are provided. That is, when the rod 46a of the cylinder 46 is extended, the support member 45 rotates in the clockwise direction in FIG. 18 around the shaft 45a against the urging force of the tension coil spring 47, while when the rod 46a contracts, The tension coil spring 47 rotates the shaft 45a counterclockwise in FIG.

  By the rotation of the support member 45, the fixing roller support member 21 rotates in the forward and reverse directions within a predetermined angle range around the shaft 45a via the movement limiting rotation member 25. Therefore, the cylinder 46 and the tension coil spring 47 rotate the fixing roller support member 21 forward and backward within a predetermined angle range around a shaft 45 a extending in the opposing direction of the pressure roller 1 and the fixing roller 11. It constitutes a moving means. The roller axis X2 of the fixing roller 11 is inclined obliquely with respect to the roller axis X1 of the pressure roller 1 when viewed from the facing direction of the pressure roller 1 and the fixing roller 11, and the length direction of the fixing roller 11 When the fixing roller support member 21 is rotated in an appropriate direction around the shaft 45a when the movement of the fixing roller 11 occurs, the inclination of the fixing roller 11 is forcibly changed and the moving direction of the fixing roller 11 is reversed. Can be.

  In addition to the first density pattern 11a described in the first embodiment, a second density pattern 11b is formed on the outer peripheral surface of the fixing roller 11 (note that only the second density pattern 11b is shown in FIG. 18). Not) The density of the second density pattern 11 b changes in the length direction of the fixing roller 11, and this density change is detected by a second photosensor 31 similar to the first photosensor 30. Thus, the moving direction of the fixing roller 11 is detected. As a result, the second photosensor 31 constitutes a moving direction detecting unit that detects the moving direction of the fixing roller 11.

  The cylinder 46 extends or contracts the rod 46 a of the cylinder 46 according to the moving direction detected by the second photosensor 31. That is, when the roller axis X2 of the fixing roller 11 is inclined with respect to the roller axis X1 of the pressure roller 1 when viewed from the direction in which the pressure roller 1 and the fixing roller 11 face each other, the fixing roller 11 has its length. When moving in the vertical direction, the rod 46a of the cylinder 46 is extended or contracted to rotate the fixing roller support member 21 in the forward direction or the reverse direction so that the inclination is corrected. As a result, the fixing roller 11 can be moved in the direction opposite to the moving direction thereof. As a result, the movement of the fixing roller in the length direction itself can be minimized, and the life of the fixing roller and the movement limiting rotation member can be further extended.

  In the eleventh embodiment, only one fixing roller support member 21 (and the movement limiting rotation member 25) is rotated. However, both the fixing roller support members 21 may be rotated. .

  Further, the fixing roller support member 21 may be a separate member from the movement restricting rotation member 25, and in this case, the fixing roller support member 21 is an axis extending in the opposing direction of the pressure roller 1 and the fixing roller 11. What is necessary is just to make it rotate around. If the fixing roller support member 21 and the movement restricting rotating member 25 are separate bodies, the movement restricting rotating member 25 may be any one of the first to third embodiments.

  Further, the rotation shaft 45a of the support member 45 may be located at any position, and is appropriately set depending on how much the roller shaft X2 of the fixing roller 11 is inclined with respect to the roller shaft X1 of the pressure roller 1. That's fine.

Embodiment 12
FIG. 19 shows a twelfth embodiment of the present invention, in which a fixing roller support member 21 having a cylindrical shape covering the entire outer peripheral surface of the fixing roller 11 and having a support portion 21a formed on the inner peripheral surface thereof is centered. By rotating around the axis, the fixing roller 11 is driven to rotate around the roller axis X2 by the frictional force between the support portion 21a of the fixing roller support member 21 and the outer peripheral surface of the fixing roller 11. It is. In this embodiment, since the fixing roller support member 21 is integrally formed with the movement limiting rotation member 25 as in the above eighth and ninth embodiments, the movement limitation rotation member 25 is also driven and rotated.

  In other words, in the present embodiment, a gear portion 21b is formed on the outer peripheral surface of one fixing roller support member 21, and the gear portion 21b is driven to rotate by a motor (not shown) or the like via the connecting shaft 7a. The gear 7 is engaged. When the drive gear 7 rotates, the fixing roller support member 21 rotates about its central axis. At this time, the fixing roller is supported by the frictional force between the support portion 21 a of the fixing roller support member 21 and the outer peripheral surface of the fixing roller 11. 11 rotates around the roller axis X2. In this way, the drive gear 7 constitutes drive means for rotating the fixing roller 11 about its roller axis X2 by rotating the fixing roller support member 21 about its central axis.

  When the pressure roller 1 is driven as in the first embodiment, the temperature of the pressure roller 1 is likely to change. Therefore, the outer diameter of the pressure roller 1 changes with the temperature change, and the recording medium. There is a possibility that the feeding speed of However, if the fixing roller 11 is driven as in the present embodiment, the fixing roller 11 is normally supported at a constant temperature, so that the outer diameter of the fixing roller 11 hardly changes, and the recording medium is surely secured. Can be sent at a constant speed.

  When the fixing roller 11 is rotated about the roller axis X2 by rotating one of the fixing roller support members 21 around the central axis as described above, the support of the one fixing roller support member 21 is supported. It is preferable that the frictional force between the support part 21 a of the other fixing roller support member 21 and the outer peripheral surface of the fixing roller 11 is small with respect to the frictional force between the part 21 a and the outer peripheral surface of the fixing roller 11. Specifically, as shown in FIG. 20, a sliding member 28 such as a fluororesin is provided on the support portion 21 a of the other fixing roller support member 21, or the surface roughness of the support portion 21 a of the other fixing roller support member 21. The frictional force with the outer peripheral surface of the fixing roller 11 may be reduced by reducing the length. In this manner, the fixing roller 11 can be reliably rotated and driven without slippage between the support portion 21a of the one fixing roller support member 21 and the outer peripheral surface of the fixing roller 11, while the other fixing is performed. Slip easily occurs between the support portion 21 a of the roller support member 21 and the outer peripheral surface of the fixing roller 11, and as a result, the roller axis X <b> 2 of the fixing roller 11 is viewed from the opposing direction of the pressure roller 1 and the fixing roller 11. As seen, even if the pressure roller 1 is inclined with respect to the roller axis X1, the thrust force generated in the fixing roller 11 is small, and the fixing roller 11 is less likely to move in the length direction.

  Further, as shown in FIG. 21, the fixing roller 11 may be rotated about the roller axis X2 by rotating both the fixing roller support members 21 about the central axis thereof. That is, both the fixing roller support members 21 are respectively formed with gear portions 21b, and two drive gears 7 respectively engaged with the gear portions 21b are attached and fixed to the connecting shaft 7a. Both fixing roller support members 21 are rotated simultaneously. This makes it difficult for the roller axis X2 of the fixing roller 11 to tilt obliquely with respect to the roller axis X1 of the pressure roller 1 when viewed from the direction in which the pressure roller 1 and the fixing roller 11 face each other. As a result, it is difficult for the fixing roller 11 to move in the length direction.

  Further, the direction of the force applied to the fixing roller support member 21 by the drive gear 7 is such that the fixing roller 11 is pressed against the pressure roller 1 in the opposite direction of the pressure roller 1 and the fixing roller 11 when viewed from the length direction of the fixing roller 11. 1 (arrow A direction in FIG. 22) or an inclination direction within 30 ° relative to the direction (arrow A direction) (arrow B or C direction in FIG. 22 (θ1 ≦ 30 °, θ2 ≦ 30 °)) It is preferable that The engagement position (circumferential position) of the drive gear 7 with respect to the gear portion 21b and the pressure angle of the drive gear 7 and the gear portion 21b may be set so as to be in such a direction. In this way, the parallelism between the center axis of the fixing roller support member 21 and the roller axis X2 of the fixing roller 11 is stably maintained, and the fixing roller 11 is less likely to move in the length direction.

  Furthermore, as the driving means, as shown in FIG. 23, instead of the driving gear 7, a driving pulley 9 that is rotationally driven by a motor or the like via a connecting shaft 9a, and the driving pulley 9 and the fixing roller support member 21. It is also possible to use a drive belt 55 that is stretched between the outer peripheral surface of the drive belt 55. By such a drive pulley 9 and drive belt 55, the fixing roller support member 21 can be rotated around its central axis. When the drive belt 55 is used in this manner, the load fluctuation is smaller than when the drive gear 7 is used, and slippage hardly occurs between the support portion 21 a of the fixing roller support member 21 and the outer peripheral surface of the fixing roller 11. Become. In addition, compared with the case where the drive gear 7 is used, vibration due to load fluctuation is less likely to occur, and no excessive pressure is applied to the fixing roller 11 due to vibration. Even when such a drive belt 55 is used, the direction of the force applied to the fixing roller support member 21 is fixed in the direction in which the pressure roller 1 and the fixing roller 11 face each other when viewed from the length direction of the fixing roller 11. A direction in which the roller 11 is pressed against the pressure roller 1 or an inclination direction within 30 ° with respect to the direction is preferable.

  In addition, the fixing roller support member 21 may be a separate member from the movement limiting rotation member 25 as in the first embodiment. In this case, the movement limitation rotation member 25 is the same as that in the first to third embodiments. Any one may be used.

(Embodiment 13)
FIG. 24 shows a thirteenth embodiment of the present invention, and the pressure roller 1 is also composed of a thin pipe material similar to the fixing roller 11.

  That is, in the present embodiment, the thin pipe material of the pressure roller 1 is made of a metal having spring properties such as stainless steel or phosphor bronze, and receives the reaction force of the pressing force on the fixing roller 11 with an elastic force. As a result, the thin pipe material of the pressure roller 1 is elastically deformed into a substantially elliptical shape in the same manner as the fixing roller 11. In this embodiment, the thin pipe material of the pressure roller 1 is made of stainless steel (SUS304) having an outer diameter of 34 mm and a wall thickness of 0.2 mm, like the fixing roller 11.

  A pressure roller support member 4 that supports the pressure roller 1 so as to be rotatable around the roller shaft (the central axis of the elastically deformed thin pipe material) is not shown below the pressure roller 1. It is fixed to the fixing member. The amount of elastic deformation of the pressure roller 1 and the fixing roller 11 is determined by the position of the pressure roller support member 4 in the vertical direction with respect to the fixing roller 11, and the position is set to a position where a predetermined pressure is obtained. The pressure roller support member 4 has a semicircular shape only in the lower half when viewed from the length direction of the pressure roller 1, and its radius is larger than the radius of the thin pipe material of the pressure roller 1 before elastic deformation. At the time of elastic deformation, the lower portion of the thin-walled pipe material substantially follows the pressure roller support member 4 at the time of elastic deformation. As a material for the pressure roller support member 4, bakelite or PPS is preferable.

  In this way, the pressure roller 1 is also made of a thin pipe material similar to the fixing roller 11, so that the nip portion that is the contact portion between the pressure roller 1 and the fixing roller 11 can be made substantially flat. As a result, various recording media (particularly double envelopes, etc.) can be transported without wrinkles.

  In the present embodiment, the pressure roller 1 is rotatably supported by the pressure roller support member 4, but for example, as shown in FIG. You may make it support rotatably by the two support rollers 52 extended in parallel with the roller axis | shaft and each supported rotatably around the center axis | shaft. In this case, a predetermined pressure can be obtained by appropriately setting the distance between the two support rollers 52 and the vertical position with respect to the fixing roller 11.

  When the pressure roller 1 is made of a thin pipe material, heating means such as a halogen lamp 17 may be provided inside the pressure roller 1. Even in this case, since the heat capacity of the pressure roller 1 is small, the warm-up time can be shortened.

(Embodiment 14)
FIG. 26 shows a fourteenth embodiment of the present invention in which deterioration of the fixing roller 11 is detected.

  That is, in the present embodiment, detection as a pressing amount detection means for detecting the pressing amount of the pressing roller 1 against the fixing roller 11 by the pressing member 5 in the vicinity of the upper end of the pressing member 5 on the side of the tension coil spring 6. A sensor 51 is provided, and the amount of pressing is calculated from the amount of movement when the contact 51a protruding downward from the main body of the detection sensor 51 is pressed and moved by the pressing member 5 toward the main body (upper side). It has come to understand. The pressing amount may be detected by any method.

  Here, when there is no crack or the like in the fixing roller 11 (thin pipe material 12), the pressing amount is within a predetermined range. However, when a crack or the like is generated, the pressing amount increases outside the predetermined range. To do. Therefore, it is possible to detect the deterioration of the fixing roller 11 when the pressing amount becomes a predetermined value or more. When the deterioration of the fixing roller 11 is detected as described above, the operation of the image forming apparatus is stopped. Note that a mechanism for releasing the pressing of the pressure roller 1 against the fixing roller 11 by the pressing member 5 may be provided, and when the deterioration of the fixing roller 11 is detected, the pressing may be released.

  As described above, since the deterioration of the fixing roller 11 is detected based on the pressing amount detected by the detection sensor 51, when the end portion of the fixing roller 11 is cracked, the operation of the image forming apparatus is immediately performed. It is possible to prevent a major trouble from occurring by stopping the operation, and to inform the user that the fixing device has failed.

  Instead of detecting the deterioration of the fixing roller 11, a limiting member that limits the pressing amount of the pressing roller 1 against the fixing roller 11 by the pressing member 5 may be provided. That is, the limiting member is provided at the same position as the detection sensor 51 so as to limit the rotation of the pressing member 5 around the rotation axis 5b. In this way, when a crack or the like occurs at the end of the fixing roller 11, the pressing member 5 comes into contact with the limiting member and cannot rotate to the fixing roller 11 side, so that the pressing amount is limited. Further, it is possible to suppress the progress of the end of the fixing roller 11 to breakage, and it is possible to prevent a major trouble from occurring.

  INDUSTRIAL APPLICABILITY The present invention is useful when a fixing roller used in an image forming apparatus such as a copying machine, a printer, or a fax machine is formed of a thin pipe material and movement of the fixing roller in the length direction is limited.

1 is a cross-sectional view showing a fixing device according to Embodiment 1 of the present invention. It is the II-II sectional view taken on the line of FIG. It is sectional drawing which shows a movement restriction | limiting rotation member. FIG. 6 is a partial side view of an end portion of a fixing roller showing a first density pattern. 5 is a cross-sectional view of the vicinity of an end portion of a fixing roller showing Embodiment 2. FIG. FIG. 6 is a view corresponding to FIG. FIG. 5 is a diagram corresponding to FIG. FIG. 6 is a diagram corresponding to FIG. FIG. 6 is a view corresponding to FIG. 5 and showing a modification of the fifth embodiment. FIG. 9 is a view corresponding to FIG. FIG. 10 is a view corresponding to FIG. 2 and showing a modification of the sixth embodiment. 10 is a plan view of a fixing device showing Embodiment 7. FIG. FIG. 10 is a view corresponding to FIG. FIG. 10 is a view corresponding to FIG. 5 and showing a modification of the eighth embodiment. FIG. 13 is a diagram corresponding to FIG. FIG. 13 is a diagram corresponding to FIG. FIG. 13 is a view corresponding to FIG. 12 showing a modification of the tenth embodiment. FIG. 13 is a diagram corresponding to FIG. FIG. 14 is a diagram corresponding to FIG. FIG. 16 is a view corresponding to FIG. 1 and showing a modification of the twelfth embodiment. FIG. 16 is a view corresponding to FIG. 1 and showing a further modification of the twelfth embodiment. It is a figure which shows the direction of the force applied to a fixing roller support member by a drive gear. FIG. 16 is a view corresponding to FIG. 1 and shows another modification of the twelfth embodiment. FIG. 20 is a diagram corresponding to FIG. FIG. 29 is a view corresponding to FIG. 2 and showing a modification of the thirteenth embodiment. FIG. 20 is a view corresponding to FIG.

Explanation of symbols

1 Pressure roller 7 Drive gear (drive means)
9 Drive pulley (drive means)
11 Fixing roller 12 Thin pipe material 13 Rubber layer 15 Sliding member 17 Halogen lamp (heating means)
21 Fixing roller support member 21a Support portion 23 Elastic member 25 Movement limiting rotation member 25a Opposing surface 30 First photosensor (rotation detection means)
31 Second photosensor (moving direction detecting means)
46 Cylinder (turning means)
47 Tension coil spring (turning means)
51 Detection sensor (Pressing amount detection means)
55 Drive belt (drive means)

Claims (25)

A pressure roller, a fixing roller that is opposed to the pressure roller in the radial direction, is pressed in the radial direction by the pressure roller, and is formed of a thin-walled pipe material that receives the applied pressure with an elastic force; and A heating means for heating the fixing roller, and a substantially arcuate shape so as to cover a portion of the outer peripheral surface of the fixing roller opposite to the pressure roller when viewed from the length direction of the fixing roller, and a portion on the opposite side A fixing roller support member having a support portion for supporting the fixing roller so as to be rotatable about its roller axis, and an annular facing surface facing the end surface of the fixing roller, and the fixing roller on the facing surface. A cylindrical movement-restricting rotating member that is supported so as to limit the movement of the fixing roller in the length direction by contacting the end surface and to rotate about the central axis as the fixing roller rotates when the contact surface comes into contact. Fixing device There,
The fixing device according to claim 1, wherein the facing surface of the movement-restricting rotating member is formed in a tapered shape that is inclined in a direction away from the end surface of the fixing roller toward a radially inner side of the facing surface. A pressure roller, a fixing roller that is opposed to the pressure roller in the radial direction, is pressed in the radial direction by the pressure roller, and is formed of a thin-walled pipe material that receives the applied pressure with an elastic force; and A heating means for heating the fixing roller, and a substantially arcuate shape so as to cover a portion of the outer peripheral surface of the fixing roller opposite to the pressure roller when viewed from the length direction of the fixing roller, and a portion on the opposite side A fixing roller support member having a support portion for supporting the fixing roller so as to be rotatable about its roller axis, and an annular facing surface facing the end surface of the fixing roller, and the fixing roller on the facing surface. A cylindrical movement-restricting rotating member that is supported so as to limit the movement of the fixing roller in the length direction by contacting the end surface and to rotate about the central axis as the fixing roller rotates when the contact surface comes into contact. Fixing device There,
The central axis of the movement limiting rotation member passes through the center of the circle of the arcuate support roller support member,
The opposing surface of the movement-restricting rotation member has a diameter of a radially inner edge of the opposing surface when viewed from the length direction of the fixing roller as D1, and the fixing roller when viewed from the length direction of the fixing roller. When D2 is twice the radius of the support portion of the support member, and t is the thickness of the thin pipe material of the fixing roller,
t ≦ D2-D1 ≦ 10t
A fixing device characterized by being formed so as to satisfy the above. A pressure roller, a fixing roller that is opposed to the pressure roller in the radial direction, is pressed in the radial direction by the pressure roller, and is formed of a thin-walled pipe material that receives the applied pressure with an elastic force; and A heating means for heating the fixing roller, and a substantially arcuate shape so as to cover a portion of the outer peripheral surface of the fixing roller opposite to the pressure roller when viewed from the length direction of the fixing roller, and a portion on the opposite side A fixing roller support member having a support portion for supporting the fixing roller so as to be rotatable about its roller axis, and an annular facing surface facing the end surface of the fixing roller, and the fixing roller on the facing surface. A cylindrical movement-restricting rotating member that is supported so as to limit the movement of the fixing roller in the length direction by contacting the end surface and to rotate about the central axis as the fixing roller rotates when the contact surface comes into contact. Fixing device There,
The movement-restricting rotating member is arranged so that only a portion of the end surface of the fixing roller opposite to the pressure roller in the facing direction of the pressure roller and the fixing roller is in contact with the facing surface of the movement-restricting rotating member. A fixing device, wherein the central axis of the movement-restricting rotating member is supported in an inclined state with respect to the roller axis of the fixing roller. The fixing device according to claim 1 or 3,
An end surface of the fixing roller is formed in a taper shape substantially along the facing surface when the movement-restricting rotating member contacts the facing surface. The fixing device according to any one of claims 1 to 3,
The fixing device is characterized in that the end surface of the fixing roller is constituted by a sliding member. The fixing device according to claim 5.
A fixing device, wherein the sliding member is integrally formed on an end surface of the fixing roller. The fixing device according to any one of claims 1 to 3,
The fixing device is characterized in that the support portion of the fixing roller support member supports the fixing roller via an elastic member. The fixing device according to claim 7.
The fixing roller support member is made of a cylindrical member that covers the entire outer periphery of the fixing roller, and a support portion is formed on the inner peripheral surface thereof.
The elastic member is an annular member whose outer diameter is smaller than the inner diameter of the fixing roller support member and whose inner diameter is larger than the outer diameter of the fixing roller,
A fixing device, wherein a portion on the pressure roller side in a facing direction of the pressure roller and the fixing roller on the outer peripheral surface of the elastic member is separated from the inner peripheral surface of the fixing roller support member. The fixing device according to any one of claims 1 to 3,
The movement restricting rotation member is configured to be rotatable about an axis extending in a facing direction between the pressure roller and the fixing roller. The fixing device according to claim 1 or 2,
The fixing roller support member is a cylindrical member that covers the entire outer periphery of the fixing roller, and has a support portion formed on the inner peripheral surface thereof, and is integrally formed with the movement limiting rotation member. A fixing device characterized. The fixing device according to claim 10.
The fixing device is characterized in that the support portion of the fixing roller support member is formed at a position separated by a predetermined distance or more from the facing surface of the movement limiting rotation member. The fixing device according to claim 10.
The movement limiting rotation members integrally formed with the fixing roller support member are respectively disposed on both sides in the length direction of the fixing roller.
At least one of the movement limiting rotation members is configured to be rotatable about an axis extending in the opposing direction of the pressure roller and the fixing roller, and is pressed toward the center in the length direction of the fixing roller. A fixing device characterized. The fixing device according to any one of claims 1 to 3,
The fixing device is characterized in that the fixing roller support member is configured to be rotatable about an axis extending in a facing direction between the pressure roller and the fixing roller. The fixing device according to claim 13.
A moving direction detecting means for detecting a moving direction when the fixing roller moves in the length direction of the fixing roller;
A rotation means for rotating the fixing roller support member forward and backward within a predetermined angle range around an axis extending in the opposing direction of the pressure roller and the fixing roller;
The fixing device is characterized in that the rotating means is configured to rotate the fixing roller support member in the forward direction or the reverse direction in accordance with the moving direction detected by the moving direction detecting means. The fixing device according to any one of claims 1 to 3,
The fixing roller support member is a cylindrical member that covers the entire outer peripheral surface of the fixing roller, and has a support portion formed on the inner peripheral surface thereof, and is disposed corresponding to both ends of the fixing roller. And is rotatably supported around the central axis of the fixing roller support member,
By rotating at least one of the fixing roller support member around its central axis, the fixing roller is rotated around the roller axis by the frictional force between the support portion of the fixing roller support member and the outer peripheral surface of the fixing roller. A fixing device comprising drive means for driving. The fixing device according to claim 15.
The driving means is configured to rotate the fixing roller about its roller axis by rotating one fixing roller support member about its central axis,
The frictional force between the support portion of the one fixing roller support member and the outer peripheral surface of the fixing roller is smaller than the friction force between the support portion of the other fixing roller support member and the outer peripheral surface of the fixing roller. A fixing device. The fixing device according to claim 15.
The driving unit is configured to rotate the fixing roller support member about its roller axis by rotating both fixing roller support members about its central axis. The fixing device according to claim 15.
The direction of the force applied to the fixing roller support member by the driving means is the direction in which the fixing roller is pressed against the pressure roller in the opposing direction of the pressure roller and the fixing roller as viewed from the length direction of the fixing roller, or the direction. A fixing device having an inclination direction within 30 °. The fixing device according to claim 15.
The driving means has a driving pulley and a belt stretched between the driving pulley and the outer peripheral surface of the fixing roller supporting member. The driving pulley and the belt rotate the fixing roller supporting member around its central axis. A fixing device characterized in that the fixing device is configured to rotate. The fixing device according to any one of claims 1 to 3,
The fixing roller support members are disposed corresponding to both ends of the fixing roller,
The thin pipe material of the fixing roller is made of metal,
A fixing device in which shot peening treatment is performed on at least an outer peripheral surface and an inner peripheral surface of both ends of the thin-walled pipe material. The fixing device according to any one of claims 1 to 3,
The fixing roller support members are disposed corresponding to both ends of the fixing roller,
A fixing device characterized in that a rubber layer is formed on the entire outer peripheral surface excluding both ends of the thin pipe material of the fixing roller. The fixing device according to any one of claims 1 to 3,
The fixing device is characterized in that the pressure roller is formed of a thin-walled pipe material that receives the reaction force of the pressure applied to the fixing roller with an elastic force. The fixing device according to any one of claims 1 to 3,
A rotation detecting means for detecting the rotation of the fixing roller;
The fixing device is configured to detect rotation of the fixing roller by detecting only a part of the fixing roller in the circumferential direction for each rotation. The fixing device according to any one of claims 1 to 3,
The pressure roller is configured to press the fixing roller in a radial direction by being pressed against the fixing roller by a pressing member,
A fixing device comprising: a restricting member for restricting a pressing amount of the pressing roller to the fixing roller by the pressing member. The fixing device according to any one of claims 1 to 3,
The pressure roller is configured to press the fixing roller in a radial direction by being pressed against the fixing roller by a pressing member,
A pressing amount detecting means for detecting the pressing amount of the pressing roller to the fixing roller by the pressing member;
A fixing device configured to detect deterioration of the fixing roller based on a pressing amount detected by the pressing amount detecting means.

Images