JP6432272B2 - Fixing apparatus and image forming apparatus - Google Patents

Description

  The present invention relates to a fixing device used for fixing a toner image on a recording medium and an image forming apparatus using such a fixing device. In particular, in a fixing device in which a pressure member is brought into contact with a fixing belt heated by a heating device and a toner image is fixed on a recording medium between the pressure member and the fixing belt that are rotationally driven. It is characterized in that it is possible to quickly and surely detect that the temperature of the fixing belt has risen abnormally and to appropriately prevent the fixing belt from being damaged.

  Conventionally, in an image forming apparatus using an electrophotographic method such as a copying machine, a printer, a facsimile, and a composite machine of these, a recording medium on which a toner image is transferred from an image carrier such as a photosensitive member is generally used as a fixing device. Thus, the fixing device fixes the toner image onto the recording medium.

  Here, as one of such fixing devices, a toner image is recorded between the pressure member and the fixing belt which are rotationally driven by bringing the pressure member into contact with the fixing belt heated by the heating device. 2. Description of the Related Art A fixing device that is fixed on a medium is known.

  In such a fixing device, when the temperature of the fixing belt rises abnormally due to slipping of the fixing belt, etc., the energization to the heating device is stopped by a safety device such as a thermostat, and the heating device The heating of the fixing belt due to is stopped.

  Further, in recent years, in such a fixing device, in order to shorten the time until the fixing belt is quickly heated by the heating device to start the fixing operation, and in order to save power of the fixing device, fixing is performed. A belt or the like having a low heat capacity is used.

  Here, when the fixing belt having such a low heat capacity is used, the temperature of the fixing belt is high and the fixing belt is deformed. Therefore, in the safety device such as the thermostat, the temperature of the fixing belt is abnormal. The rise could not be detected promptly and reliably, and after the deformation, there was a problem that the fixing belt was eventually damaged, resulting in damage around the fixing belt.

  In Patent Document 1, a displacement detection means for detecting deformation of the fixing belt is provided below the fixing belt, and when the deformation of the fixing belt is detected by the displacement detection means, the fixing belt is heated by the heating device. Some have been controlled.

  However, the direction in which the fixing belt is deformed is not necessarily constant, and when the fixing belt is deformed in a direction different from the direction in which the displacement detecting means is provided, the deformation of the fixing belt can be detected appropriately. There was a problem of disappearing.

JP 2013-57896 A

  The present invention relates to a fixing device in which a pressure member is brought into contact with a fixing belt heated by a heating device so that a toner image is fixed on a recording medium between the pressure member and the fixing belt that are rotationally driven. Therefore, it is an object of the present invention to make it possible to quickly and surely detect that the temperature of the fixing belt has risen abnormally and to appropriately prevent the fixing belt from being damaged.

In the first fixing device according to the present invention, in order to solve the above-described problem, an endless fixing belt, a heating device that heats the fixing belt, and a pressure member that contacts the fixing belt, In a fixing device that fixes a toner image on a recording medium between a rotationally driven pressure member and a fixing belt, a deformation direction restriction that restricts the heat-deforming fixing belt to be deformed in a specific direction A deformation amount detecting means for detecting that the deformation amount of the fixing belt has reached a predetermined amount, and when the deformation amount detecting means detects that the deformation amount of the fixing belt has reached a predetermined amount. in, and a heating control means for controlling the heating device is provided, as the deformation direction regulating means, the axial end of the fixing belt, the fixing belt is restricted from moving in the axial direction opposite Braking means provided to the fixing belt deformed by heat so as to deform toward the one axial side.

  In this fixing device, the fixing belt deformed by heat is deformed in a specific direction by the deformation direction restricting means, and when the deformation amount of the fixing belt thus deformed reaches a predetermined amount, Detection is performed by the deformation amount detection unit, and based on the detection result by the deformation amount detection unit, the heating device is controlled by the heating control unit, and heating of the fixing belt is stopped.

Here, in the first fixing device, as the deformation direction restricting means, a restricting means for restricting the fixing belt from moving to the opposite side in the axial direction is provided on one axial end side of the fixing belt, the fixing belt is deformed by heat so that deform toward the one axial side.

  In addition, when the restricting means for restricting the movement of the fixing belt to the opposite side in the axial direction is provided on one end side in the axial direction of the fixing belt as described above, the axial center portion is recessed in the pressure member. It is preferable to use an inverted crown pressure roller. When the pressure roller in the reverse crown shape is rotated in this way, the peripheral speed of both sides of the pressure roller becomes faster than the peripheral speed of the central part, and the both side parts of the fixing belt are in the central part. When the fixing belt is deformed by heat because the one end side of the fixing belt is regulated by the regulating means and does not move to the opposite side as described above. The other end side of the fixing belt not provided with the regulating means is deformed so as to move to the center in the axial direction of the fixing belt.

The second fixing device according to the present invention includes an endless fixing belt, a heating device that heats the fixing belt, and a pressure member that contacts the fixing belt, and is driven to rotate. In a fixing device for fixing a toner image to a recording medium between a pressure member and a fixing belt, a deformation direction restricting means for restricting the fixing belt deformed by heat to deform in a specific direction, and the fixing Deformation amount detection means for detecting that the deformation amount of the belt has reached a predetermined amount, and the heating device when the deformation amount detection means detects that the deformation amount of the fixing belt has reached a predetermined amount And a biasing means for biasing the fixing belt in a direction in which the fixing belt is deformed .

  As such an urging means, an axial urging member for urging the fixing belt in the axial direction is provided so that the fixing belt deformed by heat is deformed toward one side in the axial direction. It is possible to provide a radial urging member for urging in the radial direction so that the fixing belt deformed by heat is deformed in the radial direction. When the biasing means is biased in the direction in which the fixing belt is deformed, it is preferable to bias the fixing belt with a force within 30% from the viewpoint of proper rotation of the fixing belt.

  In the image forming apparatus of the present invention, the fixing device as described above is used as a fixing device for fixing a toner image on a recording medium.

  In the fixing device of the present invention, the fixing belt that is deformed by heat is deformed in a specific direction by the deformation direction restricting means, and the deformation amount detecting means detects that the deformation amount of the fixing belt has reached a predetermined amount. Therefore, it becomes possible to quickly and surely detect that the temperature of the fixing belt is abnormally increased and deformed, and it is possible to appropriately prevent the fixing belt from being damaged.

1 is a schematic explanatory view showing an example of an image forming apparatus using a fixing device according to an embodiment of the present invention. 1 is a schematic explanatory diagram illustrating a fixing device according to an embodiment of the present invention. FIG. 3 is a block diagram showing a configuration for detecting and controlling the deformation amount of the fixing belt in the fixing device according to the embodiment of the present invention. FIG. 2 is a schematic cross-sectional explanatory view partially showing a state in which a deformation amount of the fixing belt is detected in the fixing device according to the first exemplary embodiment of the present invention. FIG. 3 is a schematic plan view of a pressure roller having an inverted crown shape used in the fixing device according to Embodiment 1 of the present invention. FIG. 6 is a schematic cross-sectional explanatory view partially illustrating a state in which a deformation amount of a fixing belt is detected in a fixing device according to a second exemplary embodiment of the present invention. FIG. 10 is a schematic explanatory diagram illustrating a state in which a deformation amount of the fixing belt is detected in the fixing device according to the third exemplary embodiment of the present invention. FIG. 10 is a schematic explanatory diagram illustrating a state in which the amount of deformation of the fixing belt is detected in the fixing device according to the fourth exemplary embodiment of the present invention.

  A fixing device according to an embodiment of the present invention and an image forming apparatus using the fixing device will be specifically described with reference to the drawings. The fixing device and the image forming apparatus according to the present invention are not limited to those shown in the following embodiments, and can be appropriately modified and implemented without departing from the scope of the invention.

  Here, in the image forming apparatus 1 using the fixing device 30 according to the embodiment of the present invention, as shown in FIG. 1, four imaging cartridges 10A to 10D are mounted therein.

  Here, in each of the imaging cartridges 10A to 10D, the photosensitive member 11, the charging device 12 for charging the surface of the photosensitive member 11, and the surface of the charged photosensitive member 11 are exposed according to image information. An exposure device 13 for forming an electrostatic latent image on the surface of the photoconductor 11, a developing device 14 for supplying toner to the electrostatic latent image formed on the surface of the photoconductor 11 to form a toner image, and a photoconductor And a cleaning device 15 for removing toner remaining on the surface of the photoconductor 11 after the toner image formed on the surface of the photoconductor 11 is transferred to the intermediate transfer belt 21.

  Further, in each developing device 14 in each of the imaging cartridges 10A to 10D, the color of the toner to be stored is different, and black, yellow, magenta, and cyan toners are stored.

  In this image forming apparatus 1, in each of the imaging cartridges 10A to 10D, the surface of the photoconductor 11 is charged by the charging device 12, and the surface of each photoconductor 11 thus charged is exposed to the exposure device. 13, exposure is performed according to image information, an electrostatic latent image corresponding to the image information is formed on the surface of each photoconductor 11, and the electrostatic latent image formed on the surface of each photoconductor 11 is applied to the electrostatic latent image described above. The respective color toners are supplied from the respective developing devices 14 to form toner images of the respective colors on the surface of the respective photoreceptors 11.

  Next, the toner images of each color formed on the surface of each photoconductor 11 in each of the imaging cartridges 10 </ b> A to 10 </ b> D are sequentially transferred to the intermediate transfer belt 21 and synthesized on the intermediate transfer belt 21. The formed toner image is formed, and the toner remaining on the surface of each photoconductor 11 after transfer is removed from the surface of each photoconductor 11 by the cleaning device 15.

  On the other hand, the recording medium S accommodated in the image forming apparatus 1 is fed by a paper feed roller 22 and guided to a timing roller 23, and the recording medium S is fed to the intermediate transfer belt at an appropriate timing by the timing roller 23. The toner image guided between the roller 21 and the transfer roller 24 and formed on the intermediate transfer belt 21 is transferred to the recording medium S. The toner remaining on the intermediate transfer belt 21 without being transferred to the recording medium S is removed from the intermediate transfer belt 21 by the second cleaning device 25.

  In addition, the recording medium S on which the toner image is transferred as described above is guided to the fixing device 30, and the fixing device 30 fixes the toner image on the recording medium S, and then the recording on which the toner image is fixed. The medium S is discharged by the discharge roller 27.

  Here, in the fixing device 30, as shown in FIG. 2, a heating device 32 such as a halogen heater is provided on the inner peripheral side of the endless belt-like fixing belt 31, and the fixing device 31 is heated by the heating device 32. I try to let them.

  A pressure roller 33 is provided as a pressure member 33 in contact with the fixing belt 31 so as to face the fixing belt 31, and a pad member is provided on the inner peripheral side of the fixing belt 31 facing the pressure roller 33. 34, the pressure roller 33 is brought into pressure contact with the fixing belt 31 to form a nip portion N between the pressure roller 33 and the fixing belt 31, and the pressure roller 33 is rotated in this state. As the pressure roller 33 rotates, the fixing belt 31 is driven to rotate.

  Then, the recording medium S on which the toner image t is transferred is guided to the nip N between the pressure roller 33 and the fixing belt 31, and the recording medium S is heated and pressurized in the nip N. Thus, the toner image t is fixed on the recording medium S.

  Here, in the fixing device 30 according to this embodiment, as shown in FIG. 3, the deformation belt 40 is deformed by heat by restricting movement of the fixing belt 31 in at least one direction by the deformation direction restricting means 40. When the deformation amount of the fixing belt 31 deformed in this way reaches a predetermined amount, this is detected by the deformation amount detection means 50, and the detection by the deformation amount detection means 50 is detected. Based on the result, the heating control means 60 controls the heating device 32 to stop the heating of the fixing belt 31.

(Embodiment 1)
In the fixing device 30A according to the first embodiment, when the fixing belt 31 is deformed in a specific direction by the deformation direction restricting unit 40, the fixing belt 31 is deformed toward one side in the axial direction.

  Here, in the first embodiment, when the fixing belt 31 is deformed toward one side in the axial direction, as shown in FIG. 4, the fixing belt 31 is disposed on one end side in the axial direction of the fixing belt 31 and on the opposite side in the axial direction. As the restricting means 41 for restricting the movement, a locking member 31a having a convex shape is provided on the inner periphery of one end side in the axial direction of the fixing belt 31, and the end portion on one end side in the axial direction of the fixing belt 31 is rotatable. The support member 35 is provided with an insertion portion 35a inserted on the inner peripheral side of the fixing belt 31 beyond the locking member 31a provided on the inner periphery of the fixing belt 31. An engagement portion 35b having a flange shape that is engaged with the stop member 31a and prevents the fixing belt 31 from moving to the opposite side in the axial direction is provided.

  As the pressure roller 33, as shown in FIG. 5, a pressure roller 33 a having an inverted crown shape with a recessed central portion in the axial direction is used, and the pressure roller 33 a is rotated to fix the fixing belt 31. Is rotated in the direction in which the peripheral speed of both sides of the pressure roller 33a is faster than the peripheral speed of the central portion, and the portions on both sides of the fixing belt 31 are moved to the central portion. I am trying to be energized.

  Further, when the deformation amount detecting means 50 detects that the deformation amount of the fixing belt 31 has reached a predetermined amount, the gear member 51 is provided at the end of the fixing belt 31 on the side opposite to the restricting means 41. Is provided so as to rotate together with the fixing belt 31, and an encoder 53 is attached to a transmission gear 52 that rotates in mesh with the gear member 51, and the rotation of the encoder 53 is detected by a transmission type sensor 54.

  Here, in the fixing device of the first embodiment, when the fixing belt 31 is heated and deformed, both sides of the fixing belt 31 that are driven to rotate in accordance with the rotation of the pressure roller 33a having the inverted crown shape. This portion is urged in the direction of moving to the center portion, but since one end side of the fixing belt 31 in the axial direction is regulated by the regulating means 41, the end of the fixing belt 31 to which the gear member 51 is attached. The part is deformed so as to move toward the central part in the axial direction.

  Then, the fixing belt 31 is excessively heated, and the end portion of the fixing belt 31 to which the gear member 51 is attached is greatly deformed toward the central portion in the axial direction, and the gear member 51 is detached from the transmission gear 52. Then, the transmission gear 52 and the encoder 53 are not rotated. Thus, the transmission sensor 54 detects that the encoder 53 is not rotated, so that the deformation amount of the fixing belt 31 is set to a predetermined amount. It tries to detect that it has reached.

  Further, when it is detected that the deformation amount of the fixing belt 31 has reached a predetermined amount in this way, the heating device 32 is controlled by the heating control means 60 as described above based on the detection result, The heating of the fixing belt 31 is stopped.

(Embodiment 2)
Also in the fixing device 30B according to the second embodiment, as in the fixing device 30A according to the first embodiment, the fixing belt 31 is deformed toward one side in the axial direction.

  Also in the fixing device 30B of the second embodiment, as shown in FIG. 6, the fixing belt 31 is disposed on one end side in the axial direction of the fixing belt 31 on the opposite side in the axial direction as in the fixing device 30A of the first embodiment. And a pressure roller 33a having an inverted crown shape with a recessed central portion in the axial direction is used as the pressure roller 33. In the second embodiment, the end of the fixing belt 31 provided with the restricting means 41 opposite to the one end in the axial direction is rotatably held by the support member 35 while being movable in the axial direction. Yes.

  In the fixing device according to the second embodiment, when the deformation amount detecting unit 50 detects that the deformation amount of the fixing belt 31 has reached a predetermined amount, the end of the fixing belt 31 on the side opposite to the regulating unit 41 is detected. A marker 55 is attached to the outer periphery of the portion, and a reflective sensor 56 for detecting the marker 55 is disposed on the outer peripheral side of the fixing belt 31 so as to correspond to the position of the marker 55.

  Here, in the fixing device of the second embodiment, when the fixing belt 31 is heated and deformed, as in the case of the first embodiment, the rotation of the pressure roller 33a having the inverted crown shape is performed. Along with this, both sides of the fixing belt 31 that is driven to rotate are biased in the direction in which the fixing belt 31 is moved to the central portion. The end of the fixing belt 31 to which the marker 55 on the side opposite to the means 41 is attached is deformed so as to move toward the center in the axial direction.

  Then, the fixing belt 31 is excessively heated, the end portion of the fixing belt 31 to which the marker 55 is attached is greatly deformed, and the marker 55 is no longer detected by the reflection type sensor 56, whereby the fixing belt 31 is deformed. It is detected that the amount has reached a predetermined amount.

  Further, when it is detected that the deformation amount of the fixing belt 31 has reached a predetermined amount as described above, the heating control is performed as described above based on the detection result as in the case of the first embodiment. The heating device 32 is controlled by the means 60 so that the heating of the fixing belt 31 is stopped.

(Embodiment 3)
Also in the fixing device 30C of the third embodiment, the fixing belt 31 is deformed toward one side in the axial direction as in the case of the fixing devices 30A and 30B of the first and second embodiments.

  Here, in the fixing device 30 </ b> C of the third embodiment, as shown in FIG. 7, support members 35 that rotatably support the fixing belt 31 are provided on both sides in the axial direction of the fixing belt 31.

  In the fixing device according to the third embodiment, the axial direction of the fixing belt 31 is used as the urging unit 42 that urges the fixing belt 31 in the direction in which the fixing belt 31 is deformed when the fixing belt 31 is deformed toward one side in the axial direction. An axial biasing member 42a such as a compression coil spring is provided on the support member 35 on one side of the belt, and the axial biasing member 42a is used to push one end of the fixing belt 31 in the axial direction toward the opposite side. It is fast.

  In the fixing device 30C according to the third embodiment, the axial biasing member 42a biases one end of the fixing belt 31 in the axial direction toward the opposite side. As in the fixing devices 30 </ b> A and 30 </ b> B of the first and second embodiments, the restricting means 41 for restricting the movement of the fixing belt 31 to the opposite side in the axial direction is provided, or the central portion in the axial direction is recessed as the pressure roller 33. It is not necessary to use the pressure roller 33a having a reverse crown shape.

  In the fixing device 30C according to the third embodiment, when the deformation amount detecting unit 50 detects that the deformation amount of the fixing belt 31 has reached a predetermined amount, the fixing belt 31 pressed by the axial urging member 42a. Similar to the second embodiment, the marker 55 is attached to the outer periphery of the end portion, and the reflective sensor detects the marker 55 on the outer peripheral side of the fixing belt 31 so as to correspond to the position of the marker 55. 56 is arranged.

  Here, in the fixing device 30C of the third embodiment, when the fixing belt 31 is heated and deformed, the axial urging member 42a causes the fixing belt 31 to which the marker 55 is attached on one side in the axial direction. The end portion is pushed to the opposite side, and the end portion of the fixing belt 31 to which the marker 55 is attached is deformed so as to move toward the central portion in the axial direction.

  Then, the fixing belt 31 is excessively heated, the end portion of the fixing belt 31 to which the marker 55 is attached is greatly deformed, and the marker 55 is no longer detected by the reflection type sensor 56, whereby the fixing belt 31 is deformed. It is detected that the amount has reached a predetermined amount.

  Further, when it is detected that the deformation amount of the fixing belt 31 has reached a predetermined amount in this way, as in the case of the first and second embodiments, based on the detection result, as described above. The heating device 32 is controlled by the heating control means 60 to stop the heating of the fixing belt 31.

(Embodiment 4)
In the fixing device 30D according to the fourth embodiment, when the fixing belt 31 is deformed in a specific direction by the deformation direction restricting unit 40, the fixing belt 31 is deformed in the radial direction.

  Here, in the fixing device 30 </ b> D of the fourth embodiment, as shown in FIG. 8, support members 35 that rotatably support the fixing belt 31 are provided on both sides in the axial direction of the fixing belt 31.

  In the fixing device 30D of the fourth embodiment, when the fixing belt 31 is deformed in the radial direction, the outer periphery of the fixing belt 31 on one end side in the axial direction is used as the biasing means 42 that biases the fixing belt 31 in the deforming direction. A radial urging member 42b such as a compression coil spring is provided on the side, and a pressing member 42c provided at the tip of the radial urging member 42b is brought into contact with the outer peripheral surface of the fixing belt 31, so that the fixing belt 31 is moved in the radial direction. It is energized to push inward.

  Here, it is preferable that the force urged by the pressing member 42c is such that the amount of deformation of the fixing belt 31 is within 30% because the influence on the rotation of the fixing belt 31 can be suppressed.

  In the fixing device 30D according to the fourth embodiment, when the deformation amount detecting unit 50 detects that the deformation amount of the fixing belt 31 has reached a predetermined amount, the pressure detection sensor 57 is connected to the radial biasing member. The pressure detection sensor 57 is provided on the opposite side of the pressing member 42c in 42b and detects the pressure change of the radial biasing member 42b when the fixing belt 31 is deformed inward in the radial direction.

  Here, in the fixing device 30D of the fourth embodiment, when the fixing belt 31 is heated and deformed, the outer peripheral surface of the fixing belt 31 is caused by the pressing member 42c provided at the tip of the radial biasing member 42b. The outer peripheral surface of the fixing belt 31 that is pressed inward in the radial direction and in contact with the pressing member 42c is deformed so as to move inward in the radial direction.

  Then, the fixing belt 31 is excessively heated, and the outer peripheral surface of the fixing belt 31 that is in contact with the pressing member 42c is greatly deformed radially inward, and the pressure by the radial urging member 42b is a predetermined value. When the pressure becomes smaller than this, this is detected by the pressure detection sensor 57, thereby detecting that the deformation amount of the fixing belt 31 has reached a predetermined amount.

  Further, when it is detected that the deformation amount of the fixing belt 31 has reached a predetermined amount as described above, as in the case of the first to third embodiments, based on the detection result, as described above. The heating device 32 is controlled by the heating control means 60 to stop the heating of the fixing belt 31.

  As described above, in each of the fixing devices 30A to 30D of the first to fourth embodiments, it is detected that the fixing belt 31 is excessively heated and the deformation of the fixing belt 31 is deformed by a predetermined amount or more. Since the heating of the fixing belt 31 by the device 32 is stopped, when the temperature of the fixing belt 31 rises abnormally, this is detected promptly and surely to prevent the fixing belt 31 from being damaged appropriately. Will be able to.

1: Image forming apparatuses 10A, 10B, 10C, 10D: Imaging cartridge 11: Photoconductor 12: Charging device 13: Exposure device 14: Developing device 15: Cleaning device 21: Intermediate transfer belt 22: Paper feed roller 23: Timing roller 24 : Transfer roller 25: second cleaning device 27: paper discharge rollers 30, 30A, 30B, 30C and 30D: fixing device 31: fixing belt 31a: locking member 32: heating device 33: pressure roller (pressure member)
33a: Pressure roller (pressure member) in an inverted crown shape
34: pad member 35: support member 35a: insertion portion 35b: engagement portion 40: deformation direction restricting means 41: restricting means 42: biasing means 42a: axial biasing member 42b: radial biasing member 42c: pressing member 50: Deformation amount detection means 51: Gear member 52: Transmission gear 53: Encoder 54: Transmission type sensor 55: Marker 56: Reflection type sensor 57: Pressure detection sensor 60: Heating control means N: Nip part S: Recording medium t: Toner image

Claims (6)

An endless fixing belt, a heating device that heats the fixing belt, and a pressure member that contacts the fixing belt, and a toner image between the pressure member and the fixing belt that are driven to rotate. In the fixing device for fixing the toner image on the recording medium, a deformation direction restricting means for restricting the fixing belt deformed by heat to deform in a specific direction, and detecting that the deformation amount of the fixing belt has reached a predetermined amount. A deformation amount detection unit; and a heating control unit that controls the heating device when the deformation amount detection unit detects that the deformation amount of the fixing belt has reached a predetermined amount, and the deformation direction As a restricting means, a restricting means for restricting the movement of the fixing belt to the opposite side in the axial direction is provided on one end side in the axial direction of the fixing belt, and the fixing belt deformed by heat is directed to one axial direction. A fixing device, characterized in that to form. 2. The fixing device according to claim 1 , wherein the pressure member is an inverted crown-shaped pressure roller having a recessed central portion in the axial direction. An endless fixing belt, a heating device that heats the fixing belt, and a pressure member that contacts the fixing belt, and a toner image between the pressure member and the fixing belt that are driven to rotate. In the fixing device for fixing the toner image on the recording medium, a deformation direction restricting means for restricting the fixing belt deformed by heat to deform in a specific direction, and detecting that the deformation amount of the fixing belt has reached a predetermined amount. A deformation amount detection unit; and a heating control unit that controls the heating device when the deformation amount detection unit detects that the deformation amount of the fixing belt has reached a predetermined amount, and the deformation direction A fixing device comprising a biasing unit that biases the fixing belt in a direction of deforming the regulating belt. 4. The fixing device according to claim 3 , wherein as the urging means, an axial urging member for urging the fixing belt in the axial direction is provided, and the fixing belt deformed by heat is deformed toward one side in the axial direction. A fixing device characterized by the above. 4. The fixing device according to claim 3 , wherein a radial urging member that urges the fixing belt in the radial direction is provided as the urging means, and the fixing belt that is deformed by heat is deformed in the radial direction. Fixing device to do. An image forming apparatus comprising a fixing device for fixing a toner image on a recording medium, wherein the fixing device according to claim 1 is used.

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