JP2012123388A - Fixing device and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fixing device that suppresses wear of a pressure roller by a peeling member to provide quality print images and a long life of the device.SOLUTION: A fixing device of an embodiment includes: a fixing part that comes into contact with a recording medium having an image; a pressure part that forms a nip with the fixing part; and a pressure peeling part that comes into contact with the pressure part to peel the recording medium from the pressure part, and separates from the pressure part when the pressure between the fixing part and the pressure part is reduced.

Description

  The embodiments relate to a fixing device and an image forming apparatus that are mounted on a copying machine, a printer, a multifunction peripheral, or the like, and include a sheet peeling device.

  Conventional image forming apparatuses such as Multi Function Peripheral (MFP) and printers have a fixing device that contacts a pressure roller that forms a nip together with a fixing roller at the time of fixing to release a sheet from the pressure roller after fixing. .

  In the fixing device that peels the sheet from the pressure roller by bringing the peeling member into contact with the pressure roller, if the peeling member is in contact with the pressure roller while the pressure roller rotates during non-sheet feeding, the peeling member There is a risk that the surface of the pressure roller is worn by the sliding contact with. When the surface of the pressure roller is worn, there is a possibility that the image quality of the printed image is deteriorated due to poor fixing of the toner image onto the sheet passing through the nip, or the life of the fixing device is shortened.

JP-A-8-87197

  The problem to be solved is to suppress deterioration of the image quality of the printed image due to poor fixing caused by wear of the pressure roller due to sliding contact with the peeling member, to obtain a high quality printed image and to have a long life of the fixing device. It is an object of the present invention to provide a fixing device and an image forming apparatus that can achieve the above.

  In order to achieve the above object, a fixing device according to an embodiment includes a fixing unit in contact with a recording medium having an image, a pressing unit that forms a nip with the fixing unit, and the recording medium in contact with the pressing unit. Is peeled from the pressurizing part, and a pressure peeling part separated from the pressurizing part is provided when the pressure between the fixing part and the pressurizing part is reduced.

1 is a schematic configuration diagram showing an MFP equipped with a fixing unit of an embodiment. FIG. 3 is a schematic configuration diagram of the fixing unit of the embodiment as viewed from the side. FIG. 3 is a schematic explanatory diagram illustrating driving of a pressure roller and a pressure arm of the fixing unit according to the embodiment. Schematic explanatory drawing which shows a link with the retraction | saving link when the peeling plate of embodiment is in a peeling position. Schematic explanatory drawing which shows a link with the retraction | saving link in case the peeling plate of embodiment exists in a retraction | saving position. The schematic perspective view which shows the peeling unit of embodiment. The schematic perspective view which shows the supporter edge part supported by the main body frame of embodiment. The schematic perspective view which shows the peeling nail | claw of embodiment.

  Embodiments will be described below. A color MFP (Multi Functional Peripheral) 1, which is a tandem image forming apparatus equipped with the fixing device of the embodiment shown in FIG. 1, includes a printer unit 10, a paper feeding unit 11, and a paper discharging unit 12 that are image forming units. The scanner 13 is provided. The printer unit 10 is arranged in parallel along the intermediate transfer belt 15 and includes Y (yellow), M (magenta), C (cyan), and K (black), which are provided with photosensitive drums 17Y, 17M, 17C, and 17K, respectively. The four image forming stations 16Y, 16M, 16C and 16K are provided.

  Each of the image forming stations 16Y, 16M, 16C, and 16K includes chargers 18Y, 18M, 18C, and 18K, developing devices 20Y, 20M, 20C, and the like around photosensitive drums 17Y, 17M, 17C, and 17K that rotate in the direction of arrow a. 20K, and photoreceptor cleaners 21Y, 21M, 21C, and 21K. The printer unit 10 includes a laser exposure device 22 constituting an image forming unit.

  The laser exposure device 22 irradiates the photosensitive drums 17Y, 17M, 17C, and 17K with laser beams 22Y, 22M, 22C, and 22K corresponding to the respective colors, and statically irradiates the photosensitive drums 17Y, 17M, 17C, and 17K. An electrostatic latent image is formed.

  The printer unit 10 includes a backup roller 24 and a driven roller 25 that support the intermediate transfer belt 15, and travels along the intermediate transfer belt 15 in the direction of arrow b. The printer unit 10 includes primary transfer rollers 23Y, 23M, 23C, and 23K at positions facing the respective photosensitive drums 17Y, 17M, 17C, and 17K via the intermediate transfer belt 15.

  The primary transfer rollers 23Y, 23M, 23C, and 23K primarily transfer the toner images formed on the photosensitive drums 17Y, 17M, 17C, and 17K onto the intermediate transfer belt 15 and sequentially superimpose them. Each photoreceptor cleaner 21Y, 21M, 21C, and 21K removes toner remaining on each photoreceptor drum 17Y, 17M, 17C, and 17K after the primary transfer.

  The printer unit 10 includes a secondary transfer roller 26 at a position facing the backup roller 24 via the intermediate transfer belt 15. The secondary transfer roller 26 rotates in the direction of arrow c following the intermediate transfer belt 15. The printer unit 10 takes out the sheet P, which is a recording medium, from the paper feeding unit 11 by the pickup roller 27 and moves along the conveyance path 28 in accordance with the timing at which the toner image on the intermediate transfer belt 15 reaches the position of the secondary transfer roller 26. The sheet P is fed to the secondary transfer roller 26 position. At the time of the secondary transfer, the printer unit 10 forms a transfer bias at the nip between the intermediate transfer belt 15 and the secondary transfer roller 26 and performs a secondary transfer of the toner image on the intermediate transfer belt 15 onto the sheet P all at once.

  The printer unit 10 fixes the toner image on the sheet P by the fixing unit 32 which is a fixing device, and discharges the sheet P to the paper discharge unit 12 by the discharge roller pair 30.

  The image forming apparatus is not limited to the tandem system, and the number of developing devices is not limited. The image forming apparatus may transfer the toner image directly from the photoreceptor to the recording medium.

  Next, the fixing unit 32 will be described in detail. As shown in FIG. 2, the fixing unit 32 includes a fixing belt 36 that spans between the fixing roller 33 and the tension roller 34. The fixing roller 33, the tension roller 34, and the fixing belt 36 form a fixing unit. The fixing unit 32 includes a pressure roller 37 that is a pressure unit that forms a nip with the fixing belt 36.

  The fixing roller 33 is formed, for example, by covering the cored bar 33a with a foamed rubber layer 33b. The tension roller 34 is formed by coating the surface of a metal pipe made of, for example, aluminum (Al). The material of the metal pipe may be iron, copper, stainless steel or the like. In addition, a heat pipe with better thermal conductivity may be used instead of the metal pipe. The fixing belt 36 is configured by sequentially laminating a solid rubber layer and a release layer on a metal conductive layer such as a conductive layer nickel (Ni). The pressure roller 37 is formed, for example, by including a heat-resistant silicon rubber layer 37b around the core metal 37a and covering the surface with a PFA release layer 37c.

  The fixing unit 32 includes an electromagnetic induction coil (hereinafter abbreviated as IH coil) 38 that is an induction current generating unit on the outer periphery of the fixing belt 36. The fixing unit 32 includes a fixing frame 40 that is a fixed frame that supports the fixing roller 33, the tension roller 34, the fixing belt 36, and the IH coil 38, and a pressure arm 41 that is a movable frame that supports the pressure roller 37. The fixing frame 40 is fixed to the main body frame 1 a of the MFP 1. The pressure arm 41 rotates with respect to the fixing frame 40 with the first shaft 42 as a fulcrum.

  The fixing unit 32 includes a pressure spring 43 that pulls the pressure arm 41 in the arrow d direction. Due to the spring force of the pressure spring 43, the pressure roller 37 pushes the fixing belt 36 in the direction of arrow d to form a nip 44 with the fixing belt 36. The fixing unit 32 includes a cam mechanism 46 that rotates the pressure arm 41 in the direction of the arrow f in resistance to the spring force of the pressure spring 43.

  The fixing unit 32 melts and presses the toner on the sheet P by passing the sheet P conveyed in the direction of the arrow h through the nip 44 between the fixing belt 36 and the pressure roller 37, and the toner on the sheet P. Fix the image. The fixing unit 32 has, on the exit side of the sheet P, a peeling plate 47 which is a fixing peeling portion for peeling the sheet P from the fixing belt 36 and a peeling claw 48 which is a pressure peeling portion for peeling the sheet P from the pressure roller 37. Prepare. The peeling plate 47 peels the sheet P from the fixing belt 36 without contacting the fixing belt 36. The peeling claw 48 comes into contact with the pressure roller 37 and peels the sheet P from the pressure roller 37. The fixing frame 40 supports the peeling plate 47 so as to be rotatable. The main body frame 1a of the MFP 1 supports the peeling claw 48 so as to be rotatable.

  The cam mechanism 46 includes a cam 50 that rotates about a cam shaft 50 a and a cam follower 51. The cam shaft 50 a is provided on the fixing frame 40, and the cam follower 51 is provided on the pressure arm 41. For example, while the MFP 1 is in the fixing mode or the warm-up mode, the cam 50 has a cam surface 50 b close to the cam shaft 50 a in contact with the cam follower 51. The pressure roller 37 applies pressure to the fixing belt 36 by the spring force of the pressure spring 43 via the pressure arm 41. A nip 44 having a constant width is formed between the fixing belt 36 and the pressure roller 37 by the pressure of the pressure roller 37 to ensure the fixing performance.

  For example, while the MFP 1 is in the ready mode or the pause mode, and while the sheet jam is removed by the fixing unit 32, the cam surface 50 c far from the cam shaft 50 a contacts the cam follower 51. The pressure arm 41 resists the spring force of the pressure spring 43 and rotates in the arrow f direction. The pressure roller 37 reduces the pressure applied to the fixing belt 36 via the pressure arm 41.

  By reducing the pressure applied to the fixing belt 36 by the pressure roller 37 and reducing the load applied to the fixing belt 36 and the pressure roller 37 as much as possible, the life of the fixing belt 36 and the pressure roller 37 can be extended. For example, in the ready mode, the pressure between the fixing belt 36 and the pressure roller 37 when the pressure is reduced may be such that the fixing roller can be driven to rotate by the rotation of the pressure roller 37, and the pressure value may be zero. For example, in the pause mode, the fixing belt 36 and the pressure roller 37 may be separated when the pressure is reduced.

  By reducing the pressure of the pressure roller 37 against the fixing belt 36, the fixing roller 33 that has been deformed by pressure is restored. The permanent deformation of the fixing roller 33 that is caused by the constant pressing by the pressure roller 37 is prevented.

  The warm-up mode is from when the MFP 1 is activated when the power is turned on until the fixing unit 32 reaches a fixing possible temperature. The fixing mode refers to a state during printing. The ready mode refers to a state in which the fixing unit 32 holds the fixing possible temperature and printing can be started immediately. The sleep mode is a state in which the power of the MFP 1 is on but the fixing unit 32 is not operating. While the jam is removed, the MFP 1 is turned off.

  The fixing unit 32 is shown in FIG. 3, an IH control unit 3 and a drive control unit 4 that are controlled by a main body control unit 2 that controls the entire MFP 1 are provided. The IH control unit 3 controls the high frequency current applied to the IH coil 38. The drive control unit 4 controls the rotational drive of the pressure roller 37. Further, the drive control unit 4 controls the rotational drive of the cam 50. The drive control unit 4 controls the driving of the motor 5 and controls the rotation of the cam 50 via the first gear group 6. The drive control unit 4 controls the rotation of the relay gear 8 via the second gear group 7. The relay gear 8 meshes with the pressure gear 9 that drives the pressure roller 37 and rotates the pressure roller 37.

  For example, while the MFP 1 is in the fixing mode or the warm-up mode, the relay gear 8 rotates in the arrow n direction under the control of the drive control unit 4, and the pressure roller 37 rotates in the arrow g direction via the pressure gear 9. For example, while the MFP 1 is in the ready mode or the pause mode, and while the sheet jam is removed by the fixing unit 32, the relay gear 8 is stopped under the control of the drive control unit 4. Therefore, in order to reduce the pressure of the pressure roller 37 against the fixing belt 36, when the pressure arm 41 rotates in the direction of arrow f, the pressure gear 9 meshes with the stationary relay gear 8 and moves in the direction of arrow g. To turn. After that, when the pressure arm 41 is rotated in the direction of arrow e to release the pressure reduction of the pressure roller 37 with respect to the fixing belt 36, the pressure gear 9 is engaged with the stationary relay gear 8 and in the direction of arrow r. To turn.

  As shown in FIGS. 4 and 5, the peeling plate 47 is supported by a support portion 47 b that rotates with an attachment shaft 47 a of the fixing frame 40 as a fulcrum. The peeling plate 47 has substantially the same length as the entire length of the fixing belt 36 in the width direction. A first spring 53 is provided, for example, on the rear side of the peeling plate 47 and biases the tip of the peeling plate 47 toward the fixing belt 36. The attachment shaft 47a of the fixing frame 40 resists the first spring 53 and rotatably supports the lift portion 54 that positions the peeling plate 47 at the peeling position. The fixing frame 40 includes a stud 56 and restricts the position of the lift portion 54 that rotates around the mounting shaft 47a.

  The gap adjusting screw 57 screwed to the support portion 47 b of the peeling plate 47 regulates the position of the peeling plate 47 with respect to the lift portion 54 and adjusts the width of the gap G between the leading edge of the peeling plate 47 and the fixing belt 36. .

  For example, when the MFP 1 is in the fixing mode or the warm-up mode, the peeling plate 47 is urged toward the fixing belt 36 by the first spring 53. On the other hand, when the lift portion 54 comes into contact with the stud 56, the gap G with the surface of the fixing belt 36 is maintained at the tip of the peeling plate 47 against the urging force of the first spring 53. The lift part 54 is linked to a retraction link 52 provided on the pressure arm 41. The retraction link 52 supports the roller 52 a at the tip, and the free end 54 a of the lift portion 54 is located in the internal space 52 a of the retraction link 52.

  For example, while the MFP 1 is in the ready mode or the pause mode, and further while the sheet is jammed by the fixing unit 32, the pressure arm 41 is moved in the direction of arrow f in order to reduce the pressure applied to the fixing belt 36 of the pressure roller 37. When rotating, the retraction link 52 rotates in the direction of the arrow j in conjunction with the pressure arm 41. The roller 52a pushes up the free end 54a of the lift part 54 by the rotation of the retraction link 52 in the arrow j direction. When the free end 54a is pushed up by the roller 52a, the lift portion 54 rotates in the direction of the arrow k. In conjunction with the rotation of the lift portion 54 in the direction of the arrow k, the peeling plate 47 rotates in the direction of the arrow m with the mounting shaft 47a as a fulcrum and moves to a retracted position further away from the fixing belt 36.

  When the peeling plate 47 is in the peeling position, the sheet P is reliably peeled from the fixing belt 36 with the leading end of the peeling plate 47 interposed between the fixing belt 36 and the gap G. When the peeling plate 47 is in the retracted position, even if the fixing roller 33 that has been pressure-deformed by the pressure reduction of the pressure roller 37 is restored, the tip of the peeling plate 47 may not come into contact with the fixing belt 36. , It is reliably separated from the fixing belt 36.

  As shown in FIGS. 6 to 8, a plurality of peeling claws 48 are arranged on a supporter 60 that covers the entire length of the pressure roller 37 in the longitudinal direction. The rear end 60a and the front end 60b of the supporter 60 are fixed to the rear side or the front side of the main body frame 1a, respectively. The supporter 60 includes a bracket 61 at the arrangement position of the peeling claw 48. The bracket 61 includes a bearing 62 that rotatably supports the support shaft 48a of the peeling claw 48, and a stopper 63 that regulates the rotation of the peeling claw 48.

  A second spring 64 is stretched between the peeling claw 48 and the slit 63 a formed in the stopper 63. The peeling claw 48 is supported by a fixed bracket 61 of a supporter 60 that is fixed to the main body frame 1 a, and is urged toward the pressure roller 37 by a second spring 64. For example, when the MFP 1 is in the fixing mode or the warm-up mode, the peeling claw 48 is urged toward the pressure roller 37 by the second spring 64, and the tip of the peeling claw 48 contacts and contacts the pressure roller 37. At the time of fixing, the front end of the peeling claw 48 is in contact with the pressure roller 37 to reliably peel the sheet P from the pressure roller 37.

  For example, while the MFP 1 is in the ready mode or the pause mode, and further while the sheet is jammed by the fixing unit 32, the pressure arm 41 is moved in the direction of arrow f in order to reduce the pressure applied to the fixing belt 36 of the pressure roller 37. When rotating, the pressure roller 37 moves integrally with the pressure arm 41 in the direction of arrow f. However, since the bracket 61 that supports the peeling claw 48 is fixed, the peeling claw 48 is supported by the bearing 62 of the bracket 61 and moves in the arrow s direction as the pressure roller 37 moves in the arrow f direction. Rotate. The peeling claw 48 abuts against the stopper 63 while rotating in the arrow s direction while being in contact with the surface of the pressure roller 37 moving in the arrow f direction by the urging force of the second spring 64. The rotation in the arrow s direction is stopped. Even after the rotation of the peeling claw 48 in the arrow s direction is stopped, the pressure roller 37 moves in the arrow f direction, so that the peeling claw 48 is separated from the pressure roller 37.

  The operation of the fixing unit 32 will be described. When the power is turned on and the warm-up mode of the MFP 1 is started, the drive control unit 4 stops after the cam 50 rotates and at a position where the cam surface 50 b close to the cam shaft 50 a contacts the cam follower 51. By the spring force of the pressure spring 43, the pressure arm 41 is rotated in the direction of arrow e, and the pressure roller 37 is pressed against the fixing belt 36 to form the nip 44.

  The peeling plate 47 maintains the gap G between the tip of the peeling plate 47 and the surface of the fixing belt 36 by the spring force of the first spring 53 and the restriction by the lift portion 54. The peeling claw 48 contacts the pressure roller 37 by the spring force of the second spring 64.

  With the nip 44 formed, the drive control unit 4 drives the pressure roller 37 to rotate, and the IH control unit 3 applies a high-frequency current to the IH coil 38. The pressure roller 37 is rotated in the arrow g direction, and the fixing belt 36 is driven to rotate in the arrow u direction. When the fixing belt 36 generates heat due to the magnetic flux generated by the IH coil 38 and reaches the fixable temperature, the warm-up is completed. If the MFP 1 does not immediately perform a print operation, the MFP 1 switches to the ready mode.

  When the MFP 1 starts a printing operation, the fixing unit 32 shifts from the warm-up mode to the fixing mode. In the fixing mode, the drive control unit 4 rotationally drives the pressure roller 37 with the nip 44 formed. In the fixing mode, the high frequency current applied to the IH coil 38 is adjusted by the IH control unit 3 to maintain the fixing belt 36 at the fixing temperature. The fixing unit 32 fixes the toner image on the sheet P passing through the nip 44. The peeling plate 47 that maintains the gap G from the surface of the fixing belt 36 reliably peels the sheet P that has passed through the nip 44 from the fixing belt 36. The peeling claw 48 that contacts the pressure roller 37 reliably peels the sheet P that has passed through the nip 44 from the pressure roller 37.

  When the MFP 1 is switched to the ready mode after the fixing mode is completed, the drive control unit 4 rotates the cam 50 and stops at a position where the cam surface 50c far from the cam shaft 50a contacts the cam follower 51. The pressure arm 41 rotates in the direction of arrow f, and the pressure roller 37 reduces the pressure applied to the fixing belt 36.

  When the pressure arm 41 rotates in the direction of arrow f, the peeling plate 47 is pushed up by the roller 52a of the retraction link 52 and is rotated in the direction of arrow m by the lift portion 54 that rotates in the direction of arrow k. The peeling plate 47 moves to the retracted position in conjunction with the pressure arm 41.

  When the pressure arm 41 rotates in the direction of the arrow f, the peeling claw 48 supported by the fixed bracket 61 comes into contact with the stopper 63 of the bracket 61, stops, and moves away from the pressure roller 37. In the ready mode, the high frequency current applied to the IH coil 38 is adjusted by the IH control unit 3 to maintain the fixing belt 36 at the temperature at which the temperature is kept. The drive control unit 4 rotationally drives the pressure roller 37 at a timing when a high frequency current is applied to the IH coil 38 in a state where the pressure of the pressure roller 37 with respect to the fixing belt 36 is reduced.

  In the ready mode, the load applied to the fixing belt 36 and the pressure roller 37 due to the rotation of the pressure roller 37 is reduced, and the life of the fixing belt 36 and the pressure roller 37 is extended. Since the peeling plate 47 is moved to the retracted position when the pressure roller 37 is driven to rotate, the peeling plate 47 is reliably prevented from coming into contact with the fixing belt 36. The separation claw 48 is separated from the pressure roller 37 to suppress wear due to contact between the surface of the pressure roller 37 and the separation claw 48, and the occurrence of a trace of wear on the pressure roller 37 is minimized.

  When the MFP 1 enters the pause mode through the ready mode, the main body control unit 2 stops the rotational drive of the pressure roller 37 while reducing the pressure of the pressure roller 37 with respect to the fixing belt 36, and sends it to the IH coil 38. The application of high frequency current is stopped and controlled.

  When a jam occurs during the printing operation in the fixing mode, the drive control unit 4 rotates the cam 50 and stops at a position where the cam surface 50c far from the cam shaft 50a contacts the cam follower 51. After the pressure arm 41 rotates in the direction of the arrow f and the pressure roller 37 reduces the pressure applied to the fixing belt 36, the main body control unit 2 stops the rotation of the pressure roller 37 and the IH coil 38. Stop application of high-frequency current to. By the rotation of the pressure arm 41 in the direction of the arrow f, the peeling plate 47 moves to the retracted position, and the peeling claw 48 is separated from the pressure roller 37.

  When the printing operation is started from the ready mode or the pause mode and the MFP 1 enters the fixing mode, the drive control unit 4 detects the cam surface 50b close to the cam shaft 50a in order to release the pressure reduction of the pressure roller 37 with respect to the fixing belt 36. The cam 50 is rotated until the cam contacts the cam follower 51. The pressure arm 41 rotates in the direction of arrow e to release the pressure reduction of the pressure roller 37 with respect to the fixing belt 36 and form a nip 44 between the pressure roller 37 and the fixing belt 36. In conjunction with the rotation of the pressure arm 41 in the direction of arrow e, the pressure gear 9 meshing with the stationary relay gear 8 rotates in the direction of arrow r and rotates the pressure roller 37 in the direction of arrow r. .

  When the decompression of the pressure roller 37 to the fixing belt 36 is released, the tip of the peeling plate 47 returns to the peeling position where the gap G with the surface of the fixing belt 36 is maintained. When the pressure arm 41 of the fixing unit 32 is rotated in the direction of the arrow e in order to release the pressure reduction of the pressure roller 37 with respect to the fixing belt 36, the tip of the peeling claw 48 is at the pressure roller 37. From the state of being separated from the state, the state returns to the state of contacting the pressure roller 37.

  During the period from when the tip of the peeling claw 48 is separated from the pressure roller 37 to the state where it comes into contact with the pressure roller 37, the pressure roller 37 is moved to an arrow by the meshing of the relay gear 8 and the pressure roller 37. Rotate in the r direction. When the tip of the peeling claw 48 comes into contact with the pressure roller 37, the pressure roller 37 rotates in the arrow r direction. The tip of the peeling claw 48 is prevented from biting into the pressure roller 37 and the pressure roller 37 is prevented from being damaged. The rotation of the pressure roller 37 in the direction of the arrow r may be performed by driving the motor 5, for example.

  According to this embodiment, the separation claw 48 is separated from the pressure roller 37 while the MFP 1 is in the ready mode, the pause mode, or during the jam processing. Wear on the surface of the pressure roller 37 due to contact with the peeling claw 48 can be suppressed. The occurrence of traces of wear on the pressure roller 37 is suppressed as much as possible to prevent gloss streaks due to the traces of wear on the pressure roller 37 generated on the fixed image. The separation claw 48 is separated from the pressure roller 37 while the MFP 1 is in the ready mode, the pause mode or during the jam processing, and the contact time of the separation claw 48 with the surface of the pressure roller 37 is shortened. The dirt adhering to 48 is suppressed. The occurrence of a jam caused by the dirt of the peeling claw 48 is suppressed, and the dirt of the image due to the dirt transferred to the sheet P is suppressed.

  When releasing the pressure reduction of the pressure roller 37 with respect to the fixing belt 36, the pressure roller 37 is rotated in the direction of the arrow r, and the tip of the peeling claw 48 prevents the pressure roller 37 from being damaged.

  Since the separation claw 48 is separated from the pressure roller 37 during the jam processing in the fixing unit 32, the leading end of the separation claw 48 is prevented from biting into the pressure roller 37 regardless of the removal direction of the jammed sheet P. To do. During the jam processing, the tip of the peeling claw 48 is prevented from damaging the surface of the pressure roller 37.

  The present invention is not limited to the above embodiment, and various modifications can be made. For example, the fixing unit has been described using the fixing belt, but the fixing unit is not limited thereto, and a structure having a fixing roller may be used as the fixing unit. In addition, the pressure unit has been described using a pressure roller, but the present invention is not limited thereto, and a structure having a pressure belt may be used as the pressure unit.

  Although the embodiment of the present invention has been described, this embodiment is presented as an example and is not intended to limit the scope of the invention. The novel embodiment can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. This embodiment and its modifications are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

32 ... Fixing unit 36 ... Fixing belt 37 ... Pressure roller 40 ... Fixing frame 41 ... Pressure arm 48 ... Peeling claw

Claims (6)

A fixing unit in contact with a recording medium having an image;
A pressure unit that forms a nip with the fixing unit;
A fixing device comprising: a pressure peeling unit that comes into contact with the pressure unit and peels the recording medium from the pressure unit, and is separated from the pressure unit when the pressure between the fixing unit and the pressure unit is reduced. .   The fixing device according to claim 1, wherein the pressure peeling unit is separated from the pressure unit in conjunction with the pressure reduction between the fixing unit and the pressure unit.   The apparatus further comprises a fixed frame that supports the fixing unit, and a movable frame that supports the pressure unit and rotates with respect to the fixed frame, and the pressure peeling unit is stationary while the movable frame rotates. The fixing device according to claim 1, wherein the fixing device is supported by the supporting portion.   The pressure peeling part that contacts the pressure part when the pressure release part releases the pressure reduction, and moves away from the pressure part in conjunction with the pressure reduction between the fixing part and the pressure part. The fixing device according to claim 1. An image forming unit for forming an image on a recording medium;
A fixing unit in contact with the recording medium having the image;
A pressure unit that forms a nip with the fixing unit;
An image forming apparatus comprising: a pressure peeling unit that comes into contact with the pressure unit and separates the recording medium from the pressure unit, and is separated from the pressure unit by pressure reduction between the fixing unit and the pressure unit. .   The image forming apparatus according to claim 5, wherein the pressure peeling unit is separated from the pressure unit in conjunction with the pressure reduction between the fixing unit and the pressure unit.

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