JP2014153512A - Fixing device and image forming apparatus including the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fixing device that regulates meandering of a belt stably for a long period with a simple configuration at a low cost, and an image forming apparatus including the fixing device.SOLUTION: A fixing device 5 includes a meandering regulating member 45 that is disposed on both ends in an axial direction of a fixing roller 18, and regulates meandering of a belt 26 in the axial direction of the fixing roller 18. The meandering regulating member 45 has a tapered outer peripheral part 45a arranged to face an inner peripheral surface of the belt 26. The tapered outer peripheral part 45a is formed to have an outer diameter at a central part in the axial direction smaller than that of the inner peripheral surface of the belt 26, whereas to have an outer diameter on end part sides in the axial direction larger than that of the inner peripheral surface of the belt 26.

Description

  The present invention relates to a fixing device that restricts meandering of a belt mounted on a fixing roller in the roller axial direction and an image forming apparatus including the fixing device.

  The image forming apparatus transfers a toner image formed on an image carrier such as a photosensitive drum to a recording medium, conveys the recording medium carrying the toner image toward a fixing device, and heat and pressure are applied to the fixing device. In addition, the toner image on the recording medium is fixed on the recording medium. The fixing device includes a fixing belt that is rotatably stretched between a fixing roller and a heat roller, and a pressure roller that is pressed against the fixing belt, and the recording medium is disposed between the fixing belt and the pressure roller. There is a belt fixing method in which a toner image is fixed on a recording medium while passing through the nip portion of the toner.

  In a belt fixing type fixing device, when a fixing belt stretched between rollers is rotated, the fixing belt may meander on the roller while moving in the roller axis direction. If the fixing belt meanders, it may cause a fixing failure such as the position of the toner image on the recording medium being shifted, and if the fixing belt meandering continues, the end in the width direction of the belt may be damaged.

  Therefore, a technique for suppressing the meandering of the belt is conventionally known. For example, in the fixing device described in Patent Document 1, a fixing belt suspended between a fixing roller and a suspension roller, and a fixing belt provided on both sides of a shaft end portion of the suspension roller and movable in the axial direction of the roller. A belt deviation detecting means for detecting, a supporting means for supporting the shaft end portion of the suspension roller so as to be displaceable in a direction perpendicular to the axial direction, and when the fixing belt moves in the axial direction via the belt deviation detecting means. And conversion means for converting the displacement of the shaft end portion of the suspension roller into a displacement perpendicular to the axial direction. In this configuration, when the belt meandering occurs and the fixing belt moves in the meandering direction, the belt deviation detecting means rotating together with the suspension roller is pushed by the edge of the fixing belt, and in the meandering direction of the fixing belt. Moving. As the belt deviation detecting means moves in the meandering direction, the supporting means is displaced in the direction perpendicular to the meandering direction (axial direction) by the converting means, and the suspension roller also moves in the direction perpendicular to the axial direction together with the supporting means. At this time, a force in the direction of reducing the meandering acts on the fixing belt to prevent the meandering of the belt.

  In addition, the fixing device described in Patent Document 2 swings a belt stretched around a driving roller and a meandering correction roller, a meandering detection sensor that detects the meandering of the belt by contacting the end of the belt, and a meandering correction roller. Therefore, a meandering correction cam that rotates by driving the motor and a clutch that rotates the motor by the detection result of the meandering detection sensor are provided. When the meander detection sensor detects the meander of the belt, the clutch is turned on, and the rotational force of the motor is transmitted to the meander correction cam. As a result, the meandering correction cam starts to rotate, and the meandering correction roller swings in a direction for correcting the meandering of the belt.

JP 11-65336 A (paragraphs [0038] to [0045], FIGS. 1 and 3) JP-A-5-132180 (paragraphs [0020] to [0023], FIG. 1)

  In the fixing device described in Patent Document 1, the conversion unit is configured by a plate cam member having an inclined surface that contacts the guide member of the belt deviation detection unit and converts the displacement in the meandering direction into the displacement in the perpendicular direction. The support means includes a spring that urges the guide member so as to always contact the plate cam member, and a long hole for fitting the axial end portion of the suspension roller that is movable in a direction perpendicular to the axial direction (meandering direction). It is comprised with the side plate which has. In such a configuration, the load applied to the fixing belt fluctuates at the start or end of driving of the fixing belt, and if the load applied to the fixing belt fluctuates, the position of the suspension roller becomes unstable in the long hole of the side plate. Become. Further, since the plate cam member and the guide member are in a single contact due to the bias of the spring, it is difficult to smoothly convert the axial displacement of the shaft end portion of the suspension roller into a displacement perpendicular to the axial direction.

  Further, the fixing device described in Patent Document 2 includes a detection sensor, a motor, a clutch, and a meandering correction mechanism for correcting the meandering of the fixing belt, and the device becomes complicated and expensive.

  The belt fixing system is not limited to the belt fixing system in which the belt is stretched between the two rollers, and the belt is also mounted on the fixing roller, and the fixing roller of the system in which the fixing roller is pressed against the pressure roller through the belt is also a belt. This causes the same problem as in the belt fixing method described above.

  The present invention has been made to solve the above-described problems, and provides a fixing device that regulates meandering of a belt stably for a long period of time at a low cost with a simple configuration, and an image forming apparatus including the same. For the purpose.

  In order to achieve the above object, the first invention provides an endless belt heated by heating means, a pressure roller disposed opposite to the outer peripheral surface of the belt and rotatable, and an inner peripheral surface of the belt. A fixing roller that is opposed to and rotates against the pressure roller via the belt, and is disposed at both ends of the fixing roller in the axial direction, and regulates meandering of the belt in the axial direction of the fixing roller. A fixing device that melts and fixes an unfixed toner image on the recording medium by sandwiching the recording medium between the belt and the pressure roller, and the meandering restriction member includes the belt A tapered outer peripheral portion facing the inner peripheral surface of the belt, and the tapered outer peripheral portion is formed such that an outer diameter on the central portion side in the axial direction is smaller than an inner peripheral surface of the belt. The outer diameter on the end side is It is characterized by being larger than the inner peripheral surface of serial belt.

  According to the first invention, when the belt meanders in the roller axis direction, one end of the belt comes into contact with the tapered outer peripheral portion of the meandering restriction member. When the belt further moves (meanders) in the axial direction, the contact pressure between one end of the belt and the tapered outer peripheral portion increases, and the belt is stopped at a predetermined position, thereby restricting the meandering of the belt. . As described above, the belt meandering can be stably controlled for a long period of time with an inexpensive and simple configuration in which the tapered meandering restricting members are provided at both ends of the fixing roller.

1 is a cross-sectional view illustrating an image forming apparatus including a fixing device according to an embodiment of the present invention. Side surface sectional drawing which shows the fixing device which concerns on embodiment Plan sectional drawing which shows the meandering control member of the fixing device which concerns on embodiment

  Embodiments of the present invention will be described below with reference to the drawings, but the present invention is not limited to these embodiments. Further, the use of the invention and the terms shown here are not limited thereto.

  FIG. 1 is a cross-sectional view of a tandem color printer showing an embodiment of an image forming apparatus provided with a fixing device according to the present invention. The image forming apparatus 1 includes a paper feeding unit 10 that stores paper P that is a recording medium, four image forming units 29 a to 29 d disposed above the paper feeding unit 10, and above the image forming units 29 a to 29 d. Exposure units 33a to 33d arranged, fixing device 5 arranged on the left side of image forming units 29a to 29d, paper conveyance path 20 arranged on the right side of paper feeding unit 10, and image formation A discharge unit 50 that discharges the paper P is provided at the top of the apparatus 1.

  The paper feeding unit 10 is disposed below the image forming apparatus 1, and the paper feeding unit 14 is provided with a paper feeding cassette 13 that accommodates the paper P and is detachably attached to the image forming apparatus 1. A paper transport path 20 is disposed on the right side of the paper feed unit 14, and the paper P placed in the paper feed cassette 13 is sent to the paper transport path 20 one by one by the feed roller 21. The manual feed tray 23 supplies paper P or the like of a size that is not placed on the paper supply unit 10, and includes a feed roller 22. The paper P is fed one by one to the paper transport path 20 by the feed roller 22, The fed paper P is conveyed toward the image forming units 29a to 29d.

  The image forming units 29a to 29d are arranged so as to face the sheet conveying belt 38 for each color of cyan, magenta, yellow, and black in order from the upstream side in the sheet conveying direction (the right side in FIG. 1). Each of the image forming units 29a to 29d includes photoreceptors 31a to 31d, and around the photoreceptors 31a to 31d, chargers 32a to 32d, developing devices 34a to 34d, transfer rollers 35a to 35d, and cleaners. 36a to 36d are disposed.

  The photoconductors 31a to 31d are amorphous silicon photoconductors as photosensitive materials for forming the photosensitive layer, and are arranged corresponding to each color of cyan, magenta, yellow, and black. The photosensitive layer may be an organic photoreceptor (OPC photoreceptor). The developing devices 34a to 34d are disposed on the right side of the photoconductors 31a to 31d, have a developing roller, and supply toner to the photoconductors 31a to 31d. The chargers 32a to 32d are disposed upstream of the developing devices 31a to 34d in the rotation direction of the photoconductors 31a to 31d, and uniformly charge the surfaces of the photoconductors 31a to 31d.

  The exposure units 33a to 33d are arranged on the surfaces of the photoreceptors 31a to 31d from between the chargers 32a to 32d and the developing devices 31a to 34d based on image data input to an image input unit (not shown) from a personal computer or the like. Irradiate with laser light. Electrostatic latent images are formed on the surfaces of the photoreceptors 31a to 31d by the irradiated laser light, and the electrostatic latent images are developed by the developing devices 34a to 34d.

  The sheet transport belt 38 is an endless belt stretched between the driving roller 40 and the driven roller 41, and is a belt that carries and transports the sheet P between the photoreceptors 31a to 31d and the transfer rollers 35a to 35d. Form a travel path. The transfer rollers 35a to 35d are brought into pressure contact with the photoreceptors 31a to 31d with the paper transport belt 38 interposed therebetween, thereby forming a transfer nip portion. The paper P transported from the paper transport path 20 is carried on the paper transport belt 38, and the toner images of the photoconductors 31 a to 31 d are sequentially transferred onto the paper P in each transfer nip portion by the rotation of the paper transport belt 38, and are transferred to the paper P. Is superimposed with toner images of four colors of cyan, magenta, yellow and black.

  The toner tanks 39a to 39d supply toner to the developing devices 34a to 34d, and are disposed above the image forming units 29a to 29d, and store toners of cyan, magenta, yellow, and black.

  The fixing device 5 is disposed on the downstream side of the paper conveyance belt 38, and heats and presses the paper P on which the toner image is transferred in the image forming units 29a to 29d to melt and fix the toner image on the paper P. The paper P that has passed through the fixing device 5 is discharged from the paper transport path 15 to the discharge unit 50.

  The fixing device 5 is configured as shown in FIG. FIG. 2 is a side sectional view showing the fixing device 5.

  The fixing device 5 employs a fixing method in which heating is performed by electromagnetic induction, and a fixing process is performed on a belt 26 that is a heating member, a pressure roller 19, a fixing roller 18 to which the belt 26 is integrally attached. A separation member 20 that separates the paper P from the belt 26, an induction heating unit 30 that is a heating means for supplying magnetic flux to the belt 26, a temperature detection unit 25, and a control connected to the temperature detection unit 25 and the induction heating unit 30. And a power source 61 that supplies a high-frequency current to the coil of the induction heating unit 30. The fixing roller 18 and the pressure roller 19 are rotatably supported in the longitudinal direction of the housing (not shown) of the fixing device 5, and the separation member 20, the induction heating unit 30, and the temperature detection unit 25 are fixedly supported on the housing.

  The belt 26 is an endless heat-resistant belt, in order from the inner peripheral side, for example, an induction heating layer 26a made of electroformed nickel having a thickness of 35 μm, an elastic layer 26b made of silicone rubber or the like having a thickness of 300 μm, and a thickness of 30 μm, for example. And a release layer 26c that is made of a fluororesin or the like and improves release properties when an unfixed toner image is melted and fixed at the nip portion N.

  The fixing roller 18 externally covers the belt 26 at the outer peripheral portion of the fixing roller 18 so that the belt 26 can rotate integrally. For example, the fixing roller 18 has an outer diameter of 39 mm, and has an elastic layer 18 b made of silicone rubber having a thickness of 5 to 10 mm on a stainless steel core 18 a, and the elastic layer 18 b faces the inner peripheral surface of the belt 26. doing.

  The pressure roller 19 includes a cylindrical cored bar 19a, an elastic layer 19b formed on the cored bar 19a, and a release layer 19c that covers the surface of the elastic layer 19b. For example, the pressure roller 19 has an outer diameter of 36 mm, has an elastic layer 19 b made of silicone rubber having a thickness of 3 mm on an aluminum core 19 a, and a separation made of fluororesin having a thickness of 50 μm on the elastic layer 19 b. It has a mold layer 19c. The pressure roller 19 is rotated by a driving source such as a motor (not shown), and the belt 26 and the fixing roller 18 are driven to rotate by the rotation of the pressure roller 19. A nip portion N is formed at a portion where the pressure roller 19 and the belt 26 are in pressure contact with each other. In the nip portion N, an unfixed toner image on the paper P sent from the paper transport belt 38 is heated and pressurized to be on the paper P. The toner image is fixed to the toner image.

  The separating member 20 separates the sheet 9 after the fixing process from the outer peripheral surface of the belt 26, and is made of a horizontally long plate material extending in the width direction of the belt 26. The leading end portion of the separating member 20 is disposed in the vicinity of the nip portion N on the downstream side in the sheet conveyance direction, and is disposed at a predetermined interval with respect to the outer peripheral surface of the belt 26. Note that the separation member 20 may be constituted by a separation claw provided in a plurality in the width direction of the belt 26.

  The induction heating unit 30 includes a coil 37, a bobbin 38, and a magnetic core 39, and heats the belt 26 by electromagnetic induction. The induction heating unit 30 extends in the longitudinal direction (the front and back direction of the paper surface in FIG. 2) and is disposed so as to face the belt 26 so as to surround substantially half of the outer periphery of the belt 26.

  The coil 37 is attached to the bobbin 38 by winding a plurality of times (for example, 8 turns) in a loop shape along the width direction of the belt 26 (the front and back direction of the paper surface of FIG. 2). The coil 37 is connected to a power source 61 and generates an alternating magnetic flux by a high frequency current supplied from the power source 61. The magnetic flux from the coil 37 passes through the magnetic core 39, is guided in a direction parallel to the paper surface of FIG. 2, and passes along the induction heating layer 26 a of the belt 26. An eddy current is generated in the induction heat generation layer 26a due to a change in the alternating strength of the magnetic flux passing through the induction heat generation layer 26a. When an eddy current flows through the induction heating layer 26a, Joule heat is generated by the electrical resistance of the induction heating layer 26a, and the belt 26 generates heat (self-heating).

  The temperature detection unit 25 includes a non-contact temperature detection element 25a and a thermistor 25b, and is arranged to detect the temperature of the surface of the belt 26. The non-contact temperature detecting element 25 a is disposed at a substantially central portion in the width direction of the belt 26 and detects the surface temperature of the substantially central portion of the belt 26. On the other hand, the thermistor 25 b is disposed on one end side in the axial direction of the belt 26 and detects the surface temperature on the end side of the belt 26.

  The control unit 62 includes a microcomputer and a storage element such as a RAM and a ROM, and supplies the coil 37 from the power supply 61 based on the surface temperature of the belt 26 detected by the non-contact temperature detecting element 25a and the thermistor 25b. By controlling the high-frequency current that is applied, the paper P sent to the nip portion N is appropriately fixed.

  When the belt 26 is heated and heated to a fixable temperature, the paper P sandwiched by the nip portion N is heated and pressed by the pressure roller 19 so that the powdery toner on the paper P is transferred. It is melt-fixed on the paper P. The fixed sheet P is separated from the outer peripheral surface of the belt 26 by the separation plate 20. As described above, the belt 26 is made of a thin material having good thermal conductivity and has a small heat capacity. Therefore, the fixing device 5 can be warmed up in a short time, and image formation is started quickly.

  FIG. 3 is a plan sectional view showing one end portion of the fixing device 5 having a meandering restricting member. The other end portion of the fixing device 5 has the same configuration as that shown in FIG.

  When the fixing roller 18 and the pressure roller 19 are in pressure contact with each other via the belt 26 and rotate with each other, the belt 26 moves in the axial direction of the fixing roller 18 due to the inclination of the axial centers of the fixing roller 18 and the pressure roller 19. In this embodiment, a meandering regulating member 45 that regulates meandering in the axial direction of the belt 26 is provided.

  The meandering restriction member 45 is attached to both ends of the fixing roller 18 in the axial direction via the attachment flange member 46.

  The meandering restricting member 45 is formed in a substantially cylindrical shape by an elastic material having heat resistance such as silicone rubber or silicone foam, and has a tapered outer peripheral portion 45a, a cylindrical outer peripheral portion 45b, and a fitting portion 45c.

  The attachment flange member 46 is attached by screws 47 to the cored bar 18a of the fixing roller 18 that extends long on the end side in the axial direction. The mounting flange member 46 includes a mounting outer peripheral surface 46a for fitting the meandering restriction member 45, and a flange portion 46b projecting annularly from the mounting outer peripheral surface 46a. The fitting portion 45c of the meandering restriction member 45 is attached to the mounting outer peripheral surface 46a of the mounting flange member 46 by an adhesive.

  When the meandering restriction member 45 is attached to the attachment flange member 46, one axial end portion of the meandering restriction member 45 abuts on the flange portion 46 b of the attachment flange member 46. On the other hand, when the mounting flange member 46 to which the meandering restricting member 45 is attached is attached to the cored bar 18 a of the fixing roller 18, the other axial end of the meandering restricting member 45 contacts the elastic layer 18 b of the fixing roller 18.

  In a state where the meandering restricting member 45 and the mounting flange member 46 are attached to the cored bar 18 a of the fixing roller 18, the outer peripheral surface of the belt 26 is in contact with the pressure roller 19 while the inner peripheral surface of the belt 26. The end in the belt width direction faces the tapered outer peripheral portion 45a of the meandering restricting member 45. The tapered outer peripheral portion 45a is formed such that the outer diameter on the central side (inner side) in the axial direction is smaller than the inner diameter of the belt 26 (inner peripheral surface of the belt 26), while the outer side on the end side (outer side) in the axial direction. The diameter is larger than the inner diameter of the belt 26 (the inner peripheral surface of the belt 26). Specifically, with respect to the inner diameter 40 mm of the belt 26, the tapered outer peripheral portion 45 a is set to have an outer diameter on the central side in the axial direction of 39 mm, while an outer diameter on the end side in the axial direction is 40. Set to 5 mm. In the above configuration, the pressure roller 19 is in contact with part of the outer peripheral surface of the belt 26 and the tapered outer peripheral portion 45a. However, the configuration is not limited to this configuration, and the axial length of the pressure roller 19 is fixed. The pressure roller 19 may be configured to be substantially the same as the length of the roller 18 in the axial direction so that the pressure roller 19 does not contact a part of the outer peripheral surface of the belt 26 and the tapered outer peripheral portion 45a.

  With the above configuration, when the belt 26 meanders in the axial direction (right direction in FIG. 3), the end portion of the belt 26 abuts on the tapered outer peripheral portion 45a. Further, when the belt 26 moves (meanders) toward the end in the axial direction, the contact pressure between the end of the belt 26 and the tapered outer peripheral portion 45a increases, and the belt 26 is stopped at a predetermined position. Is meandering. As described above, the belt meandering can be stably controlled for a long period of time with an inexpensive and simple configuration in which the meandering restricting member 45 having the tapered outer peripheral portion 45a is disposed at both ends of the fixing roller 18.

  The cylindrical outer peripheral portion 45b is disposed on the end side in the axial direction with respect to the tapered outer peripheral portion 45a. Specifically, the cylindrical outer peripheral portion 45b is formed in a cylindrical shape with an outer diameter of 40.5 mm, similar to the outer diameter on the end portion side of the tapered outer peripheral portion 45a. With this configuration, when the belt 26 moves by a predetermined amount in the axial direction to prevent meandering, the end of the belt 26 passes over the tapered outer peripheral portion 45a and rides on the cylindrical outer peripheral portion 45b, and the belt 26 is electroformed nickel. In the case where it is configured to include such a metal, the end portion of the belt 26 where the metal such as electroformed nickel is exposed does not damage the tapered outer peripheral portion 45a.

  The flange portion 46b of the attachment flange member 46 is formed to have an outer diameter larger than the maximum diameter of the meandering restricting member 45 (the outer diameter of the tapered outer peripheral portion 45a in the axial direction or the outer diameter of the cylindrical outer peripheral portion 45b). . This configuration causes variations in the size and shape of the tapered outer peripheral portion 45a or the cylindrical outer peripheral portion 45b, and the belt 26 moves the cylindrical outer peripheral portion 45b further to the end side in the axial direction to control meandering. Also, it abuts on the flange portion 46b and the meandering of the belt 26 is restricted.

  When the meandering restricting member 45 and the mounting flange member 46 are attached to the core metal 18a, the outer diameter of the fixing roller 18 including the elastic layer 18b is the inner diameter of the belt 26 (the inner peripheral surface of the belt 26) during the fixing process. ) Configured smaller. Specifically, the outer diameter of the elastic layer 18b is set to 39 mm with respect to the inner diameter of the belt 26 of 40 mm.

  With the above configuration, the fixing roller 18 is heated during the fixing process, so that the outer peripheral portion of the elastic layer 18 b does not contact the inner peripheral surface of the belt 26 even if the cored bar 18 a and the elastic layer 18 b are thermally expanded. Therefore, due to the thermal expansion of the cored bar 18a and the elastic layer 18b, the outer peripheral portion of the elastic layer 18b and the inner peripheral surface of the belt 26 come into contact with each other, and the belt 26 is further spread, so The nip portion N is not narrower than a predetermined width in the paper transport direction. Since the nip portion N is not narrowed, the image fixing performance is not deteriorated, and the leading end portion of the paper P that has passed through the nip portion N is conveyed to the belt 26 side, and the paper P is separated by the separating member 20 (see FIG. 2). ) To reliably separate from the outer peripheral surface of the belt 26.

  In the above-described embodiment, an example in which the meandering restricting member 45 is made of an elastic material having heat resistance is shown. However, the present invention is not limited to this, and the meandering restricting member 45 may be made of a rigid body. In this case as well, the same effects as in the above embodiment can be obtained.

  In the above embodiment, the meandering restricting member 45 has a configuration including the tapered outer peripheral portion 45a and the cylindrical outer peripheral portion 45b. However, the present invention is not limited to this, and the meandering restricting member 45 includes only the tapered outer peripheral portion 45a. The structure which has this may be sufficient. In this case as well, the same effects as in the above embodiment can be obtained.

  INDUSTRIAL APPLICABILITY The present invention can be used for a fixing device that restricts meandering of a belt that is externally mounted on a fixing roller in the axial direction of the roller, and an image forming apparatus including the fixing device.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 5 Fixing apparatus 18 Fixing roller 18a Core metal 18b Elastic layer 19 Pressure roller 20 Separating member 26 Belt 30 Induction heating part (heating means)
45 Meandering restriction member 45a Tapered outer peripheral portion 45b Cylindrical outer peripheral portion 45c Fitting portion 46 Mounting flange member 46a Mounting outer peripheral surface 46b Flange portion

Claims (6)

An endless belt heated by heating means;
A pressure roller disposed opposite to the outer peripheral surface of the belt and rotatable,
A fixing roller that is opposed to the inner peripheral surface of the belt and rotates while being pressed against the pressure roller via the belt;
A meandering regulating member disposed at both ends in the axial direction of the fixing roller and regulating meandering of the belt in the axial direction of the fixing roller,
In a fixing device that sandwiches a recording medium between the belt and the pressure roller and melts and fixes an unfixed toner image on the recording medium.
The meandering restricting member has a tapered outer peripheral portion facing the inner peripheral surface of the belt,
The tapered outer peripheral portion is formed such that the outer diameter on the central portion side in the axial direction is smaller than the inner peripheral surface of the belt, while the outer diameter on the end portion side in the axial direction is larger than the inner peripheral surface of the belt. A fixing device formed.   The fixing device according to claim 1, wherein the meandering restriction member is made of an elastic material having heat resistance.   The meandering restricting member has a cylindrical outer peripheral portion having the same diameter as the maximum diameter of the tapered outer peripheral portion disposed on the end side in the axial direction continuously to the tapered outer peripheral portion. The fixing device according to claim 1 or 2.   The fixing device according to claim 1, wherein a flange portion larger than a maximum diameter of the meandering restriction member is provided on an end portion side of the meandering restriction member in the axial direction.   The fixing roller has an elastic layer facing the inner peripheral surface of the belt, and an outer diameter of the fixing roller including the elastic layer is configured to be smaller than an inner diameter of the belt during the fixing process. The fixing device according to any one of claims 1 to 4, wherein the fixing device is characterized in that:   An image forming apparatus comprising the fixing device according to claim 1.

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