JP5440282B2 - Fixing apparatus and image forming apparatus - Google Patents

Description

  The present invention includes a fixing member and a pressure member that is in pressure contact with the fixing member, and a recording medium carrying a toner image is passed between the fixing member and the pressure member so that the toner image is transferred to the recording medium. The present invention relates to a fixing device for fixing, and an image forming apparatus having the fixing device.

  2. Description of the Related Art Conventionally, it is known to employ a fixing device of the above type in an image forming apparatus configured as a copying machine, a printer, a facsimile, or a multifunction machine having at least two of these functions. In this type of fixing device, since the fixing member and the pressure member are pressed against each other, when the recording medium is jammed between them, the pressing force is released and the jammed recording medium can be easily taken out. There is a need to. Note that releasing the pressing force means that the pressing force between the fixing member and the pressure member that are in contact with each other is weakened or the two are separated from each other.

  A fixing device provided with a pressure transmitting member and a pressure releasing member for releasing such a pressure contact force is known (see Patent Document 1). In this fixing device, the pressure transmission member applies pressure to the pressure member that is movably supported with respect to the casing, and the pressure release member is moved to the casing by its own protrusion as it swings. By pressing the body, the reaction force is used to operate the pressure transmission member in a direction that reduces the applied pressure. In this fixing device, when the pressure release member is swung, the pressure transmission member is rotated around the support portion with respect to the housing of the fixing device, so that the pressure contact force to the pressure member is released.

  Here, in order to reliably release the pressure contact force, the amount of swing of the pressure transmission member (pressure member), that is, the amount of movement of the portion of the pressure transmission member that presses the pressure member is sufficiently secured. desirable. The pressure release member operates the pressure transmission member by pressing the housing with the swinging movement of the pressure release member. Therefore, in order to secure the amount of movement of the pressure transmission member, the length of the projection It is conceivable to increase the size (the amount of protrusion of the protrusion from the swing center of the pressure release member).

  However, in the pressure release member, if the length of the protrusion is increased, a large operating force is required to swing the pressure release member. Therefore, for the operation of the pressure release member, that is, the pressure contact force release operation. The ease of operation is reduced. Here, since the pressure release member is operated via an operation lever protruding from the center of swinging, the operability for releasing the contact force is reduced by increasing the length of the operation lever. However, the size of the pressure release member is increased, which hinders the downsizing of the fixing device and the image forming apparatus.

  The present invention has been made in view of the above circumstances, and provides a fixing device capable of releasing the pressure contact force between the fixing member and the pressure member with a simple configuration without hindering downsizing. The purpose is to do.

The fixing device according to claim 1 includes a pressure member pressed against the fixing member and the fixing member is constituted is accommodated in a housing, carrying the toner image between the pressure member and the fixing member A fixing device for fixing the toner image to the recording medium by passing the recording medium, wherein the pressurizing force is movably supported with respect to the casing and presses the pressure member against the fixing member. A pressure transmission member that transmits to the pressure member; and a pressure release member that is movably supported by the pressure transmission member, and extends from the pressure transmission member toward the housing by the operation of the pressure release member. A rotation center position at which the pressure transmission member is provided in the housing in a direction in which the pressure contact force between the pressure member and the fixing member is released by bringing the fitting protrusion to contact with the housing Tomo When configured to rotate as the pivot center to , The pressure release member, the oscillating relative to the pressure transmitting member, wherein the housing and engage and centered the engagement portion pivots against the housing, the said engagement portion The rotation center position is viewed from the rotation center of the pressure transmission member so that the extension position of the fitting protrusion in the pressure transmission member approaches the rotation center by rotation with respect to the casing as the center. The pressure transmission member is moved in a direction in which the pressure contact force between the pressure member and the fixing member is released by bringing the fitting protrusion into contact with the housing while shifting in a direction of reducing the length of the radial direction. It is characterized by being configured to rotate.

  A fixing device according to a second aspect is the fixing device according to the first aspect, wherein the pressure release member is formed integrally with a guide member for guiding the recording medium.

  A fixing device according to a third aspect is the fixing device according to the first or second aspect, wherein the pressure release member is swingably supported by the pressure transmission member. .

  The fixing device according to a fourth aspect is the fixing device according to any one of the first to third aspects, wherein the pressure release member is fitted into the pressure transmission member to thereby transmit the pressure. The member is swingably assembled to the member, and is prevented from falling off from the pressure transmission member by the housing.

  A fixing device according to a fifth aspect is the fixing device according to any one of the first to fourth aspects, wherein the pressure release member is interlocked with an opening operation of a main body cover of the image forming apparatus main body. It is characterized by operating.

  A fixing device according to a sixth aspect is the fixing device according to the second aspect, wherein the pressure release member operates together with the guide member in conjunction with an opening operation of a main body cover of the image forming apparatus main body. Features.

  An image forming apparatus according to a seventh aspect includes the fixing device according to any one of the first to sixth aspects.

  In the fixing device according to claim 1, when the pressure release member is swung, the pressure transmission member rotates while shifting the rotation center position, so that the pressure release member is not enlarged and is operated by the operation of the pressure release member. Since the amount of movement of the pressure transmission member can be increased, the pressure contact force between the fixing member and the pressure member can be reliably released.

  In addition, since only the pressure transmission member and the pressure release member are provided, a simple configuration can be achieved.

  In addition to the above-described configuration, if the pressure release member is formed integrally with a guide member that guides the recording medium, the pressure return operation and the guide member closing operation are performed by a single operation. In addition, since the pressure release operation and the guide member release operation can be performed by a single operation, the operability can be improved.

  In addition to the configuration described above, if the pressure release member is supported by the pressure transmission member so as to be able to swing, the swing operation of the pressure release member with respect to the pressure transmission member can be facilitated. .

  In addition to the configuration described above, the pressure release member is swingably assembled to the pressure transmission member by being fitted to the pressure transmission member, and the casing prevents the pressure release member from falling off the pressure transmission member. As a result, it is not necessary to provide a special means for preventing the pressure release member from falling off the pressure transmission member, so that a simple configuration can be achieved and costs can be effectively reduced.

  In addition to the above-described configuration, the pressure release member operates in conjunction with the opening operation of the main body cover of the image forming apparatus main body. When the main body cover is opened, the pressure contact force between the fixing member and the pressure member is released. Therefore, the operator can handle jammed paper more easily, and when the main body cover is closed, the fixing member and the pressure member can be pressed against each other. Can do.

  In addition to the above-described configuration, the pressure release member operates together with the guide member in conjunction with the opening operation of the main body cover of the image forming apparatus main body. When the main body cover is opened, the fixing member and the pressure member Since the pressure contact force can be released and the guide member can be opened, the operator can easily handle the jammed paper, and when the main body cover is closed, the fixing member and the pressure member are pressed against each other. In addition, since the guide member can be closed, the operator can perform the return operation more easily.

  In the image forming apparatus having the fixing device having the above-described configuration, the above-described effects can be obtained, so that the size can be easily reduced.

1 is a schematic cross-sectional view of an image forming apparatus equipped with a fixing device 10 of Example 1 according to the present invention. FIG. 2 is a cross-sectional view schematically showing the fixing device 10 and its peripheral part. FIG. 2 is an external perspective view schematically showing the fixing device 10, and is an explanatory view showing a state when the pressure transmission member 20 is attached to the housing 17. 4 is a perspective view schematically showing a state in which the pressure transmission member 20 and the pressure release member 30 are assembled to the housing 17. FIG. FIG. 6 is an explanatory diagram for explaining a configuration of a pressure transmission member 20. FIG. 3 is a cross-sectional view similar to FIG. 2, showing a state when the pressure contact between the fixing roller 15 and the pressure roller 16 is released. FIG. 6 is an explanatory diagram for explaining an assembled state of the pressure transmission member 20 and the pressure release member 30 with respect to the housing 17. It is explanatory drawing for demonstrating the effect | action of the pressure transmission member 20 and the pressure release member 30. FIG. FIG. 6 is an explanatory diagram for explaining the positional relationship between the standing wall portion 17b of the fitting recess 17a of the housing 17 and the fitting protrusion portion 33 of the pressure releasing member 30 when the pressure releasing member 30 is rotated around the pin 32; Yes, (a) shows a state in which the fitting projection 33 is not fitted in the fitting recess 17a, and (b) shows a state in which the fitting projection 33 is fitted in the fitting recess 17a. Yes. FIG. 5 is a schematic cross-sectional view for explaining a configuration of an image forming apparatus 1A according to a second embodiment. FIG. 11 is a cross-sectional view similar to FIG. 10 illustrating a state in which the main body cover 1Ab is opened in the image forming apparatus 1A according to the second embodiment. FIG. 6 is a cross-sectional view similar to FIG. 2 for illustrating the configuration of a fixing device 10B of Example 3. FIG. 7 is a cross-sectional view similar to FIG. 6 for illustrating the configuration of a fixing device 10B of Example 3. FIG. 6 is a schematic cross-sectional view for explaining a configuration of an image forming apparatus 1C according to a fourth embodiment. FIG. 15 is a cross-sectional view similar to FIG. 14 illustrating a state in which the main body cover 1Cb is opened in the image forming apparatus 1C according to the fourth embodiment.

  Embodiments of the fixing device according to the present invention will be described below with reference to the drawings.

  An example of the image forming apparatus 1 having the fixing device 10 according to the present invention will be described with reference to FIGS. FIG. 1 is a schematic cross-sectional view illustrating an example of an image forming apparatus 1 on which a fixing device 10 according to the first exemplary embodiment is mounted. In the image forming apparatus 1 of the first embodiment, the photosensitive member 2 disposed in the image forming apparatus main body 1a is rotated counterclockwise. At this time, the surface of the photoconductor 2 is uniformly charged by the charging device 3 in the photoconductor 2. The charged surface of the photoreceptor 2 is irradiated with laser light L emitted from the laser optical system 4, whereby an electrostatic latent image is formed on the photoreceptor 2. The electrostatic latent image is visualized as a toner image by passing through the developing device 5.

  On the other hand, a recording medium P made of, for example, transfer paper is accommodated in a paper feed cassette 6 disposed below the photoreceptor 2. The uppermost recording medium P is fed from the sheet feeding cassette 6 between the transfer device 8 and the photosensitive member 2 by the rotation of the sheet feeding roller 7. By passing the recording medium P between them, the toner image on the photoreceptor 2 is transferred to the recording medium P. In this photoreceptor 2, transfer residual toner that adheres after the transfer of the toner image is removed by the cleaning device 9.

  The recording medium P to which the toner image T (see FIG. 2) has been transferred is further conveyed upward and passes through the fixing device 10, and at this time, the toner image T is fixed to the recording medium P. The recording medium P exiting the fixing device 10 is guided by the guide member 12 and another guide member, and is discharged onto the paper discharge tray 11 by the paper discharge roller pair 13.

  As shown in the enlarged FIG. 2, the fixing device 10 includes a fixing roller 15 that is an example of a fixing member and a pressure roller 16 that is an example of a pressure member. These rollers 15 and 16 are rotatably supported with respect to the casing 17 of the fixing device 10 and rotate in directions indicated by arrows A1 and A2 in FIG. A heater 18 is provided inside the fixing roller 15, and the fixing roller 15 is heated to a temperature suitable for fixing the toner image T by the heater.

  The pressure roller 16 is movable between a state in which the pressure roller 16 is pressed against the fixing roller 15 by receiving a pressing force from a pressure transmission member 20 described later and a state in which the pressure contact force is released. . To release the pressure contact force means to weaken the pressure contact force between the fixing roller 15 and the pressure roller 16 in contact with each other or to separate the two from each other.

  In this fixing device 10, the recording medium P carrying the toner image T transferred from the photoreceptor 2 is positioned between the fixing roller 15 and the pressure roller 16 so that the toner image T is in contact with the fixing roller 15. Sent (see arrow A4). The toner image T is fixed on the recording medium P between the fixing roller 15 and the pressure roller 16 by heating and pressing the toner.

  As described above, the fixing device 10 includes the fixing roller 15 as a fixing member and the pressure roller 16 as a pressure member in pressure contact therewith, and the toner is interposed between the fixing roller 15 and the pressure roller 16. By passing the recording medium P carrying the image T, the toner image T is fixed to the recording medium P.

  As described above, the pressure roller 16 is configured to be brought into pressure contact with the fixing roller 15 by receiving a pressing force from the pressure transmission member 20 and to be able to release the pressure contact force. The pressure transmission member 20 is provided as a pair in the fixing device 10 of the first embodiment (see FIG. 3 and the like). The pair of pressure transmission members 20 are inserted into an insertion port 19 formed in the casing 17 of the fixing device 10 as shown in FIG. 3 which is a perspective view schematically showing the fixing device 10 (see FIG. 4). ) Is provided. Since the configuration around the pair of pressure transmitting members 20 and the insertion port 19 into which the pair of pressure transmitting members 20 is inserted is the same, only one is shown in FIGS. 2 and 6 and the other is omitted. 2 corresponds to a cross-sectional view taken along the line II in FIG. The insertion port 19 is formed in a slit shape in each end region as viewed in the longitudinal direction of the casing 17 of the fixing device 10.

  A fitting recess 17 a is provided above each insertion port 19. This fitting recess 17a is a recess that enables fitting of a fitting projection 33 of a pressure release member 30 described later, and a standing wall that rises on the back side (upwardly obliquely to the left when viewed from the front in FIG. 3). A wall portion 17b, a horizontal wall portion 17c that forms a lower surface, a side wall portion 17d that forms a side surface, and an eaves wall that protrudes forward from the upper end of the standing wall portion 17b (toward the right front side in FIG. 3). Part 17e. In the fitting recess 17a, when a later-described pressure release member 30 is swung, the tip of the fitting projection 33 is brought into contact with the standing wall 17b while the fitting projection 33 is engaged with the flange wall portion 17e. The fitting protrusion 33 is rotated around the contact (engagement) position, and the fitting protrusion 33 is fitted so as to push the fitting protrusion 33 downward diagonally to the right. .

  A space S that is partitioned by the horizontal wall portion 17c and the side wall portion 17d and has a diameter larger than that of the insertion port 19 is formed in front of the fitting recess 17a. This space S is a place where a pressure release member 30 (described later) that is swingably provided in the pressure transmission member 20 is disposed in a state where each pressure transmission member 20 is inserted into the insertion port 19.

  Each pressure transmission member 20 has a plate shape as a whole, and as shown in FIG. 5, an engaging portion 21 at the lower end, an attachment hole 23 at the upper end, a spring receiving projection 24 at the upper end, and a pressing surface 25. Have. Each pressure transmission member 20 applies a large pressure to the pressure roller 16 so that the pressure roller 16 and the fixing roller 15 are pressed against each other. For this reason, since each pressure transmission member 20 requires high intensity | strength, it is desirable to form with a metal material.

  The engaging portion 21 of the pressure transmitting member 20 is formed by cutting out so as to be able to engage with the pin 26 fixed to the housing 17 (see FIG. 2). The engaging portion 21 can be engaged while allowing the relative movement of the pin 26 (see FIG. 2) between the lower end surface 21a and the upper end surface 21b, and the pin 26 is attached to the lower end surface 21a. Each pressure transmission member 20 can be rotated around the pin 26 in a contacted (engaged) state (see FIG. 2), and the pin 26 is contacted (engaged) with the upper end surface 21b. ) (See FIG. 6), each pressure transmission member 20 can be rotated around the pin 26. The engagement portion 21 is set between the lower end surface 21a and the upper end surface 21b in accordance with the amount of movement of the rotation center position in the pressure transmission member 20 described later. In the state where each pressure transmission member 20 is inserted into the housing 17 through the insertion port 19 (see FIG. 4), the engaging portion 21 is engaged with the pin 26 (see FIG. 2).

  The mounting hole 23 is a place where a pin 32 (see FIG. 3) of the pressure release member 30 described later is rotatably fitted. For this reason, the pressure release member 30 to be described later can swing with respect to the pressure transmission member 20.

  The spring receiving projection 24 is a place where one end of the tension spring 41 is locked (see FIG. 2). As shown in FIG. 2, the tension spring 41 is an urging member for applying a pressing force that presses the pressure roller 16 against the fixing roller 15 to the pressure roller 16 via each pressure transmission member 20. is there. The other end of the tension spring 41 is locked to the housing 17. Each pressure transmission member 20 receives a biasing force from the tension spring 41 in a state where it does not receive a biasing force obliquely downward to the right from each pressure release member 30 described later, and is pinned to the lower end surface 21 a of the engaging portion 21. The pressure roller 16 is pressed by being oscillated and biased around the pin 26 in a state where the pin 26 is in contact.

  The pressing surface 25 is a portion that transmits pressure to the pressure roller 16 in order to press the pressure roller 16 against the fixing roller 15 in the pressure transmission member 20 biased by the tension spring 41. The pressing surface 25 is a place where each pressure transmission member 20 comes into contact (pressure contact) with a bearing 16b fitted to each shaft end portion 16a of the pressure roller 16. Each pressure transmission member 20 is swung in the counterclockwise direction in FIG. 2 around the pin 26 in a state where the pin 26 is brought into contact with the lower end surface 21a of the engaging portion 21 by urging from the tension spring 41. Since it is biased, the pressure roller 16 is pressed against the fixing roller 15 by pressing the bearing 16 b with the pressing surface 25.

  As described above, each pressure transmission member 20 is supported movably with respect to the casing 17 of the fixing device 10, and transmits pressure applied to the pressure roller 16 to press the pressure roller 16 against the fixing roller 15. It has a function. In the first embodiment, each pressure transmission member 20 is supported to be swingable around the pin 26 with respect to the housing 17. With such a configuration, the pressure roller 16 is pressed against the fixing roller 15 and pressurizes the toner (toner image T) on the recording medium P passing between the fixing roller 15 and the pressure roller 16. Can do. Each pressure release member 30 is provided to release the transmission of the pressing force from the pressure transmission member 20 to the pressure roller 16, that is, the pressure contact force between the pressure roller 16 and the fixing roller 15.

  As shown in FIG. 3, each pressure release member 30 is provided in each of the pressure transmission members 20 that make a pair. The pressure release member 30 includes an operation lever portion 31, a pin 32, and a fitting projection portion 33. Since the pressure release member 30 is touched by the operator's hand, it is desirable that the pressure release member 30 be formed of a resin material from the viewpoint of operability and the viewpoint of suppressing its own heating.

  The operation lever portion 31 of the pressure release member 30 is a portion that is operated to swing the pressure release member 30 in order to release the pressure contact force between the pressure roller 16 and the fixing roller 15. The pin 32 is configured to rotatably support the pressure release member 30 with respect to the pressure transmission member 20 by being rotatably fitted in an attachment hole 23 provided in the pressure transmission member 20. When the pressure release member 30 is swung around the pin 32, the fitting protrusion 33 engages with the flange wall portion 17e of the fitting recess 17a and the tip thereof contacts the standing wall portion 17b of the fitting recess 17a. It has a function of fitting into the fitting recess 17a so as to be pushed down diagonally to the right by a rotational force centered on the contact (engagement) portion with the flange wall portion 17e. Hereinafter, this operation (action) is also referred to as rotation when the fitting protrusion 33 of the pressure release member 30 is fitted into the fitting recess 17a.

  The pressure release member 30 is inserted by being partitioned by a horizontal wall portion 17c and a side wall portion 17d in front of the fitting recess 17a in a state where each pressure transmission member 20 is inserted into the insertion port 19 (see FIG. 4). It is located in the space S whose diameter is larger than that of the mouth 19. For this reason, the pressure release member 30 is positioned between the pressure transmission member 20 and the side wall portion 17d of the housing 17 in the space S as shown in FIG. Thereby, the pin 32 of the pressure release member 30 fitted in the mounting hole 23 of the pressure transmission member 20 can be prevented from dropping from the mounting hole 23 by the side wall portion 17d. Therefore, in the fitting structure between the pin 32 of the pressure release member 30 and the mounting hole 23 of the pressure transmission member 20, the pressure release member 30 is prevented from dropping from the pressure transmission member 20 without providing any special drop-off prevention means. it can. In other words, the casing 17 of the fixing device 10 can prevent the pressure release member 30 from falling off the pressure transmission member 20. Here, since the pressure transmission member 20 always receives a biasing force in the direction close to the pressure roller 16 by the tension spring 41, that is, the direction in which the pressure transmission member 20 is maintained in the space S, the pressure release member 30 is By being assembled to the pressure transmission member 20, the dropout is reliably prevented (see FIG. 2). As described above, since it is not necessary to provide a special means for preventing the pressure release member 30 from dropping from the pressure transmission member 20, the fixing device 10 can have a simple configuration and the fixing device 10 and thus the image forming apparatus. 1 can be effectively reduced.

  In this way, each pressure release member 30 is rotatably supported by each pressure transmission member 20, and in the first embodiment, each pressure release member 30 is relative to each pressure transmission member 20 due to its peripheral configuration. It is supported so that it can swing freely.

  As shown in FIG. 2, each pressure release member 30 does not restrain each pressure transmission member 20 when the fitting protrusion 33 is not fitted in the fitting recess 17 a of the housing 17. Then, no urging is applied to each pressure transmission member 20, and each pressure transmission member 20 is in contact (engaged) with the lower end surface 21 a by urging from the tension spring 41. As a result, the bearing 16 b is pressed by the pressing surface 25, and the pressure roller 16 is pressed against the fixing roller 15.

  Here, when the recording medium is jammed between the fixing roller 15 and the pressure roller 16 and the operation of the image forming apparatus 1 is stopped and the rotation of the fixing roller 15 and the pressure roller 16 is stopped, the jamming occurs. It is necessary to remove the recording medium (hereinafter referred to as jammed paper). In this case, in the image forming apparatus 1 according to the first embodiment, as shown in FIG. 1, an operator such as a user or a serviceman is supported by the image forming apparatus main body 1 a through a pin 42 so as to be able to open and close. The main body cover 1b is rotated in the direction of the arrow A5 to open the main body cover 1b, and the fixing device 10 is exposed to the outside. Next, the operator pulls the operation lever portion 31 to rotate each pressure release member 30 around the pin 32 in the direction indicated by the arrow A6 in FIG. Then, in each pressure release member 30, the fitting projection 33 is fitted into the fitting recess 17 a of the housing 17, so that the operation force to the operation lever portion 31 is fitted to the fitting projection 33. It acts as a rotational force centered on the engagement (contact) portion with the recess 17a. Specifically, each pressure release member 30 has the fitting protrusion 33 engaged with the flange wall 17e of the fitting recess 17a, and the tip of the fitting protrusion 33 is the standing wall 17b in the fitting recess 17a. And the fitting projection 33 is fitted into the fitting recess 17a by moving around the engagement portion so as to be pushed down diagonally to the right. To do. As a result, the pressure transmission member 20 to which each pressure release member 30 is connected via the pin 32 is pushed down diagonally to the right against the urging force of the tension spring 41. Then, the pressure transmission member 20 is in a state in which the pin 26 is in contact with the upper end surface 21b of the engaging portion 21 from the state in which the lower end surface 21a of the engaging portion 21 is in contact with the pin 26 fixed to the housing 17. It is rotated around the pin 26 while moving to. That is, the pressure transmission member 20 has its upper center surface 21b abutted against the pin 26 from the state where the lower end surface 21a abuts the pin 26 inside the engaging portion 21 at the rotation center position thereof. It is rotated around the pin 26 while shifting to the state. Therefore, as shown in FIG. 6, each pressure transmission member 20 rotates around the pin 26 in a direction away from the pressure roller 16, that is, the fixing roller 15, and the pressing force on the pressing surface 25 against the bearing 16b is weakened. Alternatively, the bearing 16b and the pressing surface 25 are separated from each other. As a result, the pressure contact force between the fixing roller 15 and the pressure roller 16 due to transmission of the applied pressure from the pressure transmission member 20 can be released. That is, the pressure contact force between the fixing roller 15 and the pressure roller 16 is weakened, or the two rollers are separated from each other. As described above, the pressure transmission member 20 is operated in the direction in which the pressure contact force between the pressure roller 16 and the fixing roller 15 is released by the operation of each pressure release member 30 (oscillation in the first embodiment).

  Thereafter, in the first embodiment, the fixing roller 15 and the pressure roller are rotated by rotating the guide member 12 rotatably supported by the housing 17 via the pin 43 in the direction indicated by the arrow A7 in FIG. An upper opening (not shown) between 16 is opened. Thereby, the operator can easily remove jammed paper (not shown) from between the fixing roller 15 and the pressure roller 16. In the image forming apparatus 1, the pressure roller 16 can be brought into pressure contact with the fixing roller 15 again by performing a procedure (operation) opposite to the above-described procedure.

  As described above, the pressure release member 30 is fitted to the fitting recess 17a of the casing 17 of the fixing device 10 by its swinging, and by rotation (rotational force) around the engagement point at that time, The pressure transmission member 20 is operated in a direction to release the pressure contact force between the pressure roller 16 and the fixing roller 15. Therefore, in the fixing device 10, the pressure transmission member 20 can be reliably operated by the pressure release member 30, and the pressure contact force between the fixing roller 15 and the pressure roller 16 can be released.

  In the fixing device 10 according to the first exemplary embodiment of the present invention, the pressure contact force between the pressure roller 16 and the fixing roller 15 is obtained by simply pulling the operation lever portion 31 of each pressure release member 30 (see arrow A6 in FIG. 2). Can be reliably released, and an increase in size is prevented. This will be described in detail below with reference to FIGS. FIG. 8 is an explanatory diagram for explaining the operation of the pressure transmission member 20 and the pressure release member 30. In FIG. 8, the pin 26 and the standing wall portion 17b of the fitting recess 17a of the housing 17 and the pressure transmission member 20 and the pressure release member 30 after rotating with the rotation center position shifted are indicated by solid lines. The pressure transmission member 20 and the pressure release member 30 when rotating without shifting the rotation center position are indicated by a two-dot chain line. FIG. 9 illustrates the positional relationship between the standing wall portion 17b of the fitting recess 17a of the housing 17 and the fitting protrusion 33 of the pressure releasing member 30 when the pressure releasing member 30 is rotated around the pin 32. (A) shows the state where the fitting projection 33 is not fitted in the fitting recess 17a, and (b) shows the fitting projection 33 fitted in the fitting recess 17a. Indicates the state. In FIG. 8, for the sake of easy understanding, the wall surface corresponding to the standing wall portion 17b of the fitting recess 17a of the housing 17 with which the tip of the fitting protrusion 33 of the pressure release member 30 abuts is indicated by a one-dot chain line. Show.

  As described above, when the operation lever portion 31 is pulled, the fitting projection 33 is fitted into the fitting recess 17a of the housing 17, so that the fitting projection 33 and the fitting recess 17a are engaged. Each pressure release member 30 rotates around the engaging portion. By this rotation, the pressure transmission member 20 connected to each pressure release member 30 via the pin 32 is pushed down diagonally to the right, and the lower end surface 21a is moved to the inside of the engaging portion 21 at the rotation center position. While the upper end surface 21b is in contact with the pin 26 from the state in contact with the pin 26, it is rotated around the pin 26.

  Here, in the pressure transmission member 20, the fitting projection 33 of the pressure release member 30 rotated around the pin 32 is fitted into the fitting recess 17a (the tip of the fitting projection 33 is the fitting recess 17a). The amount of rotation of the pressure transmission member 20, that is, the amount of movement of the pressing surface 25 is substantially equal to the fitting protrusion 33. Is determined by the length dimension. This is due to the following. As shown in FIG. 9, the amount of rotation of the pressure transmission member 20 is such that the fitting protrusion 33 of the pressure release member 30 is not fitted in the fitting recess 17a of the housing 17 (the pressure transmission member 20 is added). A distance d1 from the rotation center position (reference numeral 32a) of the pressure release member 30 to the standing wall portion 17b of the fitting recess 17a in a state where the pressure roller 16 is in pressure contact with the fixing roller 15; Difference between the distance d2 from the rotation center position 32a of the pressure release member 30 to the standing wall portion 17b of the fitting recess 17a in a state where the fitting protrusion 33 is fitted in the fitting recess 17a of the housing 17. Determined by d3. This difference d3 is determined by the length dimension of the fitting projection 33 considering the distance between the rotation center position 32a of the pressure release member 30 and the standing wall 17b of the fitting recess 17a. The amount of rotation of the member 20 is substantially determined by the length dimension of the fitting projection 33.

  Here, in the fixing device 10, in order to reliably release the pressure contact force between the pressure roller 16 and the fixing roller 15, it is desirable that the rotation amount of the pressure transmission member 20 is large. It is conceivable to increase the size. However, in the pressure release member 30, if the length dimension of the fitting protrusion 33 is increased, a large operating force is required to rotate the pressure release member 30. The operability (the degree of ease of operation) for the release operation is reduced. In order to prevent a decrease in operability associated with the increase of the fitting protrusion 33, it is conceivable to increase the length of the operation lever 31. However, the increase in the size of the pressure release member 30 may be increased. As a result, the fixing device 10 and thus the image forming apparatus 1 are prevented from being downsized.

  Therefore, in the fixing device 10 according to the first embodiment of the present invention, when the pressure transmission member 20 is rotated for releasing the pressure contact force, the rotation center position of the pressure transmission member 20 is viewed from the rotation center. The length in the radial direction is shifted in the direction of decreasing. This reduces the length dimension from the pin 26 which is the rotation center position in the pressure transmission member 20 to the proximal end position of the fitting projection 33, that is, the rotation of the pressure release member 30 from the pin 26 (the center position). It is intended to reduce the distance to the center position 32a. In this way, by fitting the rotational center position of the pressure transmission member 20 in a direction that reduces the length of the radial direction viewed from the rotational center, the fitting contacted with the standing wall portion 17b of the fitting recess 17a. Since the extension position of the joint portion 33 from the pressure transmission member 20 can be relatively moved closer to the rotation center of the pressure transmission member 20, the rotation center position of the pressure transmission member 20 is not shifted. The amount of rotation of the pressure transmission member 20 can be increased without increasing the length of the fitting protrusion 33.

  Here, a state of rotation of the pressure transmission member 20 when the rotation center position is not shifted is shown by a two-dot chain line in FIG. In FIG. 8, when the rotation center position is shifted (see the pressure transmission member 20 indicated by the solid line) and when the rotation center position is shifted (see the pressure transmission member 20 indicated by the two-dot chain line), the pressure The size of the transmission member 20 and the pressure release member 30 (the length of the fitting protrusion 33) and the positional relationship between the pin 26 and the standing wall 17b (see the alternate long and short dash line) are the same. When the rotation center position is not shifted, in the pressure transmission member 20, as shown by a two-dot chain line in FIG. 8, the standing wall of the fitting recess 17a viewed from the rotation center position (pin 26) of the pressure transmission member 20 Since the extension position of the fitting projection 33 abutting on the portion 17b from the pressure transmission member 20 is substantially the length of the pressure transmission member 20, the fitting projection 33 is formed on the standing wall 17b. The rotation amount of the pressure transmission member 20 due to the contact is smaller than the rotation amount when the rotation center position of the pressure transmission member 20 is shifted (in the two-dot chain line rather than the pressure transmission member 20 indicated by the solid line). The pressure transmission member 20 shown is positioned counterclockwise). That is, in the pressure transmission member 20, the vertical wall portion 17 b as viewed in the rotational radial direction is obtained by shifting the rotational center position of the pressure transmission member 20 in a direction that reduces the length of the radial direction viewed from the rotational center. Since the position of the fitting projection 33 interposed between the fitting projection 33 and the standing wall 17b can be moved closer to the center of rotation, the amount of rotation of the pressure transmission member 20 by interposing the fitting projection 33 with the standing wall 17b. Can be increased.

  As described above, in the fixing device 10 according to the first embodiment, the rotation center position of the pressure transmission member 20 is shifted in a direction to reduce the length in the radial direction when viewed from the rotation center, thereby rotating the pressure transmission member 20. Since the amount of movement can be increased, the pressure contact force between the fixing roller 15 and the pressure roller 16 can be reliably released. Therefore, the amount of rotation of the pressure transmission member 20 can be increased without increasing the length of the fitting protrusion 33, so that the pressure contact force between the pressure roller 16 and the fixing roller 15 can be reliably released. However, the fixing device 10 and thus the image forming apparatus 1 can be greatly contributed to downsizing.

  Further, in the fixing device 10 according to the first embodiment, the housing 17 is provided with the fitting recess 17a having the flange wall portion 17e, and the housing 17 can be shifted in the rotation center position so as to have the above-described function. However, since the pressure transmission members 20 supported rotatably and the pressure release members 30 supported swingably are provided, the pressure roller 16 and the fixing roller can be simply configured. The pressure contact force with 15 can be reliably released.

  Furthermore, in the fixing device 10 according to the first embodiment, the housing 17 has a ridge wall so that the fitting release portion 33 of the pressure release member 30 is fitted to rotate the pressure release member 30 diagonally downward to the right. A fitting recess 17a having a portion 17e is provided, and the engaging portion 21 of each pressure transmission member 20 can be engaged while allowing relative movement of the pin 26 between the lower end surface 21a and the upper end surface 21b. Therefore, the rotation center position of the pressure transmission member 20 can be shifted in a direction that reduces the length of the radial direction as viewed from the rotation center.

  In the fixing device 10 according to the first exemplary embodiment, the pressure transmission member 20 in a state in which the pin 26 is in contact with the lower end surface 21 a of the engaging portion 21 is oscillated and biased by the tension spring 41 around the pin 26. Since the pressure roller 16 is pressed, the pressure roller 16 can be pressed by efficiently using the urging force of the tension spring 41. That is, in the fixing device 10, the substantial length dimension of the pressure transmission member 20 in the radial direction viewed from the rotation center is variable with respect to the pin 26 that is the rotation center of the pressure transmission member 20. By increasing the length, it is possible to ensure a sufficient pressing force to the pressure roller 16 by the urging force of the tension spring 41 attached to the tip position (spring receiving projection 24). By reducing the length dimension, it is possible to secure the amount of rotation of the pressure transmitting member 20 for releasing the pressure contact force by bringing the fitting protrusion 33 into contact with the housing 17 (the standing wall portion 17b). It is possible.

  Therefore, in the fixing device 10 according to the first embodiment of the present invention, the pressure contact force between the fixing roller 15 (fixing member) and the pressure roller 16 (pressure member) can be easily configured without hindering downsizing. Can be released.

  In the above-described first embodiment, the housing 17 is provided with the fitting recess 17a having the flange wall portion 17e, and each pressure release member 30 is provided with the fitting protrusion 33. However, the pressure release member When 30 is swung around the pin 32, the pressure release member 30 engages with the housing 17, and the rotation center position of the pressure transmission member 20 is set by the rotation with respect to the housing 17 around the engagement portion. What is necessary is just to push down the pressure release member 30 diagonally downward to the right so as to shift the radial dimension as viewed from the center of rotation, and is not limited to the first embodiment described above.

  In the first embodiment, the pin 32 of the pressure release member 30 has a cylindrical shape. However, any pin may be used as long as the pressure release member 30 is rotatably supported by the pressure transmission member 20. However, the present invention is not limited to the first embodiment. For example, by making the pin 32 into a cam shape, the movable range of the pressure transmission member 20 can be expanded, and the moving range of the bearing 16b, that is, the moving range of the pressure roller 16 can be increased.

  Next, an image forming apparatus 1A according to Embodiment 2 of the present invention will be described. The second embodiment is an example in which the same fixing device 10 as that of the first embodiment is mounted, but the configuration of the main body cover 1Ab of the image forming apparatus main body 1Aa is different. Since the basic configuration of the image forming apparatus 1A according to the second embodiment is the same as that of the fixing device 10 and the image forming apparatus 1 according to the first embodiment described above, the same reference numerals are given to portions having the same configuration. Detailed description is omitted. FIG. 10 is a schematic cross-sectional view for explaining the configuration of the image forming apparatus 1A according to the second embodiment. FIG. 11 shows a state in which the main body cover 1Ab is opened in the image forming apparatus 1A according to the second embodiment. It is sectional drawing similar to FIG.

  In the image forming apparatus 1A according to the second embodiment, as shown in FIGS. 10 and 11, an open side engaging claw 51 and a closed side engaging claw 52 are provided on the main body cover 1Ab of the image forming apparatus main body 1Aa. It has been. When the main body cover 1Ab is opened, the release-side engagement claw 51 is engaged with the operation lever portion 31 of the pressure release member 30 of the fixing device 10 to pull the operation lever portion 31, that is, to release the pressure release member 30. (See arrow A8 in FIG. 11). Further, when closing the opened main body cover 1Ab, the closing side engaging claw 52 engages with the operation lever portion 31 of the pressure release member 30 of the fixing device 10, thereby pushing the operation lever portion 31 into operation, that is, releasing the pressure. The member 30 is swung in the pressing direction (the direction opposite to the arrow A8 in FIG. 11). The opening-side engagement claw 51 and the closing-side engagement claw 52 are movement trajectories associated with the swinging of the operation lever portion 31 of the pressure release member 30 as viewed from the movement trajectories associated with the opening / closing operations of the main body covers 1Ab. The overlap amount and location are set to be optimized.

  Since the image forming apparatus 1A and the fixing device 10 according to the second embodiment have basically the same configuration as the image forming apparatus 1 and the fixing device 10 according to the first embodiment, the same effects as the first embodiment are basically obtained. be able to.

  In addition, in the image forming apparatus 1A according to the second embodiment, when the main body cover 1Ab is opened, the pressure contact force between the fixing roller 15 (fixing member) and the pressure roller 16 (pressure member) can be released. One can handle jammed paper more easily.

  In the image forming apparatus 1A according to the second embodiment, when the main body cover 1Ab is closed, the fixing roller 15 (fixing member) and the pressure roller 16 (pressure member) can be brought into pressure contact with each other. A return operation can be performed.

  Further, in the image forming apparatus 1A according to the second embodiment, the opening side engaging claw 51 and the closing side engaging claw 52 are optimized and set with respect to the operation lever portion 31 of the pressure release member 30. With the opening / closing operation of the main body cover 1Ab, the engagement of the release-side engagement claw 51 or the closure-side engagement claw 52 with the pressure release member 30 (operation lever portion 31) is released, or the pressure release member 30 ( It is possible to prevent the operation lever portion 31) from being damaged and the open side engaging claw 51 and the closing side engaging claw 52 from being damaged.

  Therefore, in the fixing device 10 of the second embodiment, the pressure contact force between the fixing roller 15 (fixing member) and the pressure roller 16 (pressure member) can be released with a simple configuration without hindering downsizing. Can do.

  Next, a fixing device 10B according to Example 3 of the present invention will be described. The third embodiment is an example in which the configuration of the fixing device 10B is different from the first embodiment. Since the basic configuration of the fixing device 10B according to the third embodiment is the same as that of the fixing device 10 according to the first embodiment, the same reference numerals are given to portions having the same configuration, and detailed description thereof is omitted. . 12 is a cross-sectional view similar to FIG. 2 for explaining the configuration of the fixing device 10B of the third embodiment, and FIG. 13 is similar to FIG. 6 for explaining the configuration of the fixing device 10B of the third embodiment. FIG.

  As shown in FIGS. 12 and 13, the fixing device 10 </ b> B according to the third embodiment is provided with a pressure release member 30 </ b> B in which the pressure release member 30 and the guide member 12 in the first embodiment are integrated. . In the pressure release member 30B, a guide portion 53 corresponding to the guide member 12 of the first embodiment is provided integrally with an operation lever portion 31B, a pin (not shown) corresponding to the pin 32, and a fitting projection portion 33B. The pressure release member 30 is the same as the pressure release member 30 of the first embodiment. For this reason, in the fixing device 10B, when the operation lever portion 31B of the pressure release member 30B is pulled, the rotation center position of the pressure transmission member 20 is shifted as the fitting projection portion 33B is fitted into the fitting recess 17a. By rotating around the pin 26, the pressure contact force between the pressure roller 16 and the fixing roller 15 can be released, and the guide portion 53 can be rotated in the direction indicated by the arrow A9 in FIG. The upper opening (not shown) between the fixing roller 15 and the pressure roller 16 can be opened.

  Since the fixing device 10B according to the third embodiment basically has the same configuration as that of the fixing device 10 according to the first embodiment, the same effects as those of the first embodiment can be basically obtained.

  In addition, in the fixing device 10B of the third embodiment, when the operation lever portion 31B of the pressure release member 30B is pulled, the pressure contact force between the fixing roller 15 (fixing member) and the pressure roller 16 (pressure member) is released. In addition, since an upper opening (not shown) between the fixing roller 15 and the pressure roller 16 can be opened, the operator can handle jammed paper more easily. In other words, in the fixing device 10B, the pressure release operation and the guide member release operation can be performed by a single operation, so that the operability can be improved.

  In the fixing device 10B of the third embodiment, when the operation lever portion 31B of the pressure release member 30B is pushed in, the fixing roller 15 (fixing member) and the pressure roller 16 (pressure member) can be brought into pressure contact with each other. Since the upper opening (not shown) between the fixing roller 15 and the pressure roller 16 can be closed, the operator can perform the return operation more easily. In other words, in the fixing device 10B, since the pressure return operation and the guide member closing operation can be performed by a single operation, the operability can be improved.

  Therefore, in the fixing device 10B according to the third exemplary embodiment, the pressure contact force between the fixing roller 15 (fixing member) and the pressure roller 16 (pressure member) can be released with a simple configuration without hindering downsizing. Can do.

  Next, an image forming apparatus 1C according to Embodiment 4 of the present invention will be described. The fourth embodiment is an example in which the same fixing device 10B as that of the third embodiment is mounted, but the configuration of the main body cover 1Cb of the image forming apparatus main body 1Ca is different. Since the basic configuration of the image forming apparatus 1C according to the fourth embodiment is the same as that of the fixing device 10B and the image forming apparatus 1 according to the first embodiment, the same configuration is the same. Reference numerals are assigned and detailed description thereof is omitted. FIG. 14 is a schematic cross-sectional view for explaining the configuration of the image forming apparatus 1C according to the fourth embodiment. FIG. 15 shows a state in which the main body cover 1Cb is opened in the image forming apparatus 1C according to the fourth embodiment. It is sectional drawing similar to FIG.

  In the image forming apparatus 1C according to the fourth embodiment, as illustrated in FIGS. 14 and 15, the main body cover 1Cb of the image forming apparatus main body 1Ca is provided with an open side engaging claw 54 and a closing side engaging claw 55. It has been. When the main body cover 1Cb is opened, the release-side engaging claw 54 engages with the operation lever portion 31B of the pressure release member 30B of the fixing device 10B, thereby pulling the operation lever portion 31B, that is, releasing the pressure release member 30B. (See arrow A10 in FIG. 15). Further, when closing the opened main body cover 1Cb, the closing side engaging claw 55 engages with the operation lever portion 31B of the pressure release member 30B of the fixing device 10B, thereby pushing the operation lever portion 31B, that is, releasing the pressure. The member 30B is swung in the pressing direction (the direction opposite to the arrow A10 in FIG. 15). The opening-side engagement claw 54 and the closing-side engagement claw 55 are movement trajectories associated with the swinging of the operation lever portion 31B of the pressure release member 30B, as viewed in the movement trajectories associated with the opening / closing operations of the main body covers 1Cb. The overlap amount and location are set to be optimized.

  Since the image forming apparatus 1C and the fixing device 10B according to the fourth embodiment have basically the same configuration as the image forming apparatus 1 and the fixing device 10 according to the first embodiment, the same effects as the first embodiment are basically obtained. be able to.

  In addition, in the image forming apparatus 1C according to the fourth embodiment, when the main body cover 1Cb is opened, the pressure contact force between the fixing roller 15 (fixing member) and the pressure roller 16 (pressure member) can be released and the fixing can be performed. Since an upper opening (not shown) between the roller 15 and the pressure roller 16 can be opened, the operator can handle jammed paper more easily. In other words, in the fixing device 10B, since the main body cover opening operation, the pressure releasing operation, and the guide member opening operation can be performed by one operation, the operability can be further improved.

  In the image forming apparatus 1C according to the fourth exemplary embodiment, when the main body cover 1Cb is closed, the fixing roller 15 (fixing member) and the pressure roller 16 (pressure member) can be brought into pressure contact with each other, and the fixing roller 15 and pressure can be pressed. Since the upper opening (not shown) between the rollers 16 can be closed, the operator can perform the return operation more easily. In other words, in the fixing device 10B, since the main body cover closing operation, the pressure return operation, and the guide member closing operation can be performed by one operation, the operability can be further improved.

  Furthermore, in the image forming apparatus 1C according to the fourth embodiment, the opening-side engagement claw 54 and the closing-side engagement claw 55 are optimized and set with respect to the operation lever portion 31B of the pressure release member 30B. With the opening / closing operation of the main body cover 1Cb, the engagement of the opening side engaging claw 54 or the closing side engaging claw 55 with the pressure releasing member 30B (operation lever portion 31B) is disengaged, or the pressure releasing member 30B ( It is possible to prevent the operating lever portion 31B) from being damaged and the open side engaging claw 54 and the closing side engaging claw 55 from being damaged.

  Therefore, in the fixing device 10B according to the fourth embodiment, the pressure contact force between the fixing roller 15 (fixing member) and the pressure roller 16 (pressure member) can be released with a simple configuration without hindering downsizing. Can do.

  In each of the above-described embodiments, the fixing device according to the present invention has been described. However, the fixing member and the pressure member pressed against the fixing member are housed in a casing, and the fixing member and the pressure member are disposed between the fixing member and the pressure member. A fixing device that fixes a toner image to a recording medium by passing the recording medium carrying the toner image on the recording medium, and is movably supported with respect to the housing and applies pressure to press the pressing member against the fixing member. A direction having a pressure transmission member that transmits to the pressure member, and a pressure release member that is movably supported by the pressure transmission member, and the pressure contact force between the pressure member and the fixing member is released by the operation of the pressure release member The pressure release member is engaged with the housing by swinging with respect to the pressure transmission member, and the pressure member is rotated by rotation with respect to the housing around the engagement portion. The pressure contact force between the fuser and the fixing member is released The fixing device is configured to rotate the pressure transmitting member while shifting the rotation center position in a direction to reduce the length of the radial direction viewed from the rotation center. It is not limited to examples.

  Further, in each of the above-described embodiments, the pressure transmission member 20 has a plate shape as a whole and is configured to include the engagement portion 21, the attachment hole 23, the spring receiving projection portion 24, and the pressing surface 25. A pressure force that is supported movably with respect to the housing and that presses the pressure member against the fixing member is transmitted to the pressure member, and the pressure contact force between the pressure member and the fixing member is activated by the operation of the pressure release member. As long as it is actuated in the direction in which is released, the invention is not limited to the above-described embodiments.

  Further, in each of the above-described embodiments, the pressure release member 30 (30B) is configured to include the operation lever portion 31 (31B), the pin 32, and the fitting projection portion 33 (33B). Direction in which the pressure contact force between the pressure member and the fixing member is released by the rotation with respect to the housing centering on the engagement portion. In addition, it is only necessary to rotate the pressure transmission member while shifting the rotation center position in a direction to reduce the length in the radial direction when viewed from the rotation center, and the present invention is not limited to the above-described embodiments. Absent.

  As mentioned above, although the imaging device of the present invention has been described based on the embodiment and each example, the specific configuration is not limited to each of these examples, and is designed without departing from the gist of the present invention. Changes or additions are permitted.

1, 1A, 1C Image forming apparatus 1a, 1Aa, 1Ca Image forming apparatus body 1b, 1Ab, 1Cb Body cover 10, 10B Fixing device 15 Fixing roller 16 (as a fixing member) Pressure roller 17 (as a pressure member) Housing 17a Fitting recess 17e (becomes an engagement point with the pressure release member in the housing) Eave wall portion 20 (Becomes an engagement point with the pressure release member in the housing) 20 Pressure transmitting member 30, 30B Pressure release Member P Recording medium T Toner image

Japanese Patent No. 4094822

Claims (7)

A pressure member pressed against the fixing member and the fixing member is constituted is accommodated in a housing, the toner image by passing a recording medium carrying the toner image between the pressure member and the fixing member A fixing device for fixing to the recording medium,
A pressure transmission member that is movably supported with respect to the housing and transmits a pressure force that presses the pressure member against the fixing member, and a pressure release that is movably supported by the pressure transmission member; And having a member
By operating the pressure release member, a fitting protrusion extending from the pressure transmission member toward the housing is brought into contact with the housing, so that the pressure contact force between the pressure member and the fixing member is increased. The pressure transmission member is configured to rotate about the rotation center position provided in the housing in the released direction, and the rotation center position .
Said pressure release member, the oscillating relative to the pressure transmitting member, wherein the housing and engage and centered the engagement portion pivots against the housing, around the said engagement portion The radius when the rotation center position is viewed from the rotation center of the pressure transmission member so that the extension position of the fitting protrusion in the pressure transmission member approaches the rotation center by the rotation with respect to the housing. The pressure transmitting member is rotated in a direction in which the pressure contact force between the pressure member and the fixing member is released by causing the fitting protrusion to abut against the housing while shifting in the direction of reducing the length of the direction. A fixing device configured to be moved.   The fixing device according to claim 1, wherein the pressure release member is formed integrally with a guide member that guides the recording medium.   The fixing device according to claim 1, wherein the pressure release member is swingably supported by the pressure transmission member.   The pressure release member is swingably assembled to the pressure transmission member by fitting to the pressure transmission member, and is prevented from falling off the pressure transmission member by the housing. The fixing device according to any one of claims 1 to 3.   5. The fixing device according to claim 1, wherein the pressure release member operates in conjunction with an opening operation of a main body cover of the image forming apparatus main body.   The fixing device according to claim 2, wherein the pressure release member operates together with the guide member in conjunction with an opening operation of a main body cover of the image forming apparatus main body.   An image forming apparatus comprising the fixing device according to claim 1.

Images