JP2011252961A - Fixing device and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate detaching or attaching of a fixing device without providing a specific mechanism, and to realize an easy operation by a simple and inexpensive configuration.SOLUTION: A fixing unit 18 is detachably mounted in an apparatus body of an image forming apparatus 10 for forming an image on a recording material P, and holds/conveys the recording material P so as to heat an image formed on the recording material P in a fixing nip N between a fixing film unit 18a and a pressure roller 18b. The fixing unit includes a pressure-contact mechanism 28 that performs a pressure-contacting or a contact releasing operation between the fixing film unit 18a and the pressurizing roller 18b. The pressure-contact mechanism 28 includes an engaging part 33a which moves to an engaging position where the engaging part engages with the apparatus body to restrict dismounting of the fixing unit 18 from the apparatus body or moves to an engagement releasing position where the engaging part releases the engagement with the apparatus body to cancel the restriction of dismounting of the fixing unit 18 from the apparatus body. The movement is associated with a pressure-contacting or a contact releasing operation between the fixing film unit 18a and the pressurizing roller 18b.

Description

  The present invention relates to a fixing device that fixes an unfixed image on a recording material and an image forming apparatus including the fixing device.

  Generally, in an image forming apparatus employing an electrophotographic system such as a copying machine, a facsimile machine, or a printer, a recording material onto which a toner image has been transferred is sent to a fixing device and heated to fix the toner image. . As a fixing device that heats and fixes an unfixed toner image on a recording material, a heat roller type fixing device has been widely used. However, in recent years, a film heating type fixing device has been put into practical use from the viewpoint of quick start and energy saving. It has become.

  In these fixing devices, the heating member and the pressure member are pressed against each other so as to sandwich and convey the recording material onto which the toner image is transferred, and the recording material is formed at the pressure contact portion (fixing nip portion) between the heating member and the pressure member. The toner image formed on is fixed by heating and pressing. However, if the image forming apparatus stops while the recording material is nipped in the fixing nip, if you try to remove the recording material while the heating member and pressure member are in pressure contact, a large force is required to remove it. Or the recording material may be damaged. Therefore, a fixing device provided with a pressure contact mechanism for releasing the pressure contact between the heating member and the pressure member is known.

  In the above-described image forming apparatus, when the fixing device reaches the end of its life or fails due to some abnormality, it is known that a service person performs maintenance work such as replacement of the fixing device using a tool. Furthermore, a technique is known in which a fixing device is unitized and the fixing device only needs to be replaced in order to enable maintenance work without using a tool (see Patent Document 1).

JP 2001-318554 A

  However, in order to be able to replace the fixing device without using a tool, it is necessary to provide a dedicated mechanism for facilitating the removal or installation of the fixing device, which complicates the configuration and reduces the cost. There is also a problem that it takes.

  Accordingly, an object of the present invention is to facilitate the removal or mounting of the fixing device without providing a dedicated mechanism, and to achieve this with a simple and low-cost configuration.

  In order to solve the above problems, the present invention is removably attached to the main body of an image forming apparatus that forms an image on a recording material, and is formed on the recording material at a pressure contact portion between a heating member and a pressure member. An image heating apparatus that sandwiches and conveys a recording material to heat an image, and includes a pressure contact mechanism that presses or releases pressure contact between the heating member and the pressure member, and the pressure contact mechanism includes the heating member and the heating member. In conjunction with the operation of pressing or releasing the pressure member, the engagement position that engages with the apparatus main body to restrict the removal of the image heating apparatus from the apparatus main body or the engagement with the apparatus main body is released. It has an engaging part which moves to the disengagement position which cancels regulation of removal of the image heating device from the device main body.

  According to the present invention, since the press-contact mechanism also functions to restrict or release the image heating device, there is no need to provide a dedicated mechanism for facilitating the removal or mounting of the fixing device. Moreover, this can be realized with a simple and low-cost configuration without increasing the number of parts.

1 is a schematic cross-sectional view illustrating a schematic configuration of an image forming apparatus having a fixing device in a detachable manner. FIG. 2 is a partial vertical cross-sectional view illustrating an enlarged periphery of a fixing device in the image forming apparatus. FIG. 2 is an external perspective view showing an enlarged main part of a fixing device in the image forming apparatus. FIG. 3 is a partial longitudinal sectional view showing a pressure contact state of the fixing device. FIG. 4 is a partial vertical cross-sectional view illustrating a pressure contact released state (first pressure released state) of the fixing device. FIG. 3 is a partial external perspective view showing a first pressure released state of the fixing device. FIG. 6 is a partial external perspective view showing a second pressure released state of the fixing device. 2 is a block diagram schematically showing a configuration of a control system in the image forming apparatus. FIG. 6 is a flowchart showing a relationship between operation control of a pressure contact mechanism and removal restriction or restriction release of a fixing unit.

  Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. However, the dimensions, materials, shapes, and relative arrangements of the components described in the following embodiments should be appropriately changed according to the configuration of the apparatus to which the present invention is applied and various conditions. Therefore, unless specifically stated otherwise, the scope of the present invention is not intended to be limited thereto.

[First Embodiment]

  Hereinafter, an image forming apparatus having a detachable fixing device will be described as an example.

  First, the overall configuration of the image forming apparatus will be described, and then a fixing device that can be attached to and detached from the main body of the image forming apparatus will be described. Here, a laser printer will be described as an example of the image forming apparatus.

  In the image forming apparatus (laser printer) 10 shown in FIG. 1, for example, when image information is sent from an external computer, it is received by a video controller (not shown) provided in the image forming means. The image forming unit forms an image to be transferred to the recording material on the image carrier based on the received information. Specifically, the received image information is converted into light modulation information 11 a by the laser emission writing unit 11 and emitted. The light modulation information 11a emitted from the laser emission writing unit 11 is spot-shaped on a photosensitive drum 121 as an image carrier provided in the process cartridge 12 while being scanned in the main scanning direction (axial direction of the drum). Is imaged. The light spot irradiated on the photosensitive drum 121 rotated in the sub-scanning direction (recording material conveyance direction) orthogonal to the main scanning direction is reciprocated in the main scanning direction, whereby the above-described image is formed on the photosensitive drum 121. An electrostatic latent image corresponding to the information is formed. Then, an unfixed toner image is formed by supplying developer (toner) to the electrostatic latent image on the photosensitive drum 121 from a developing device 122 that is also integrally provided in the process cartridge 12. The

  The process cartridge 12 described above is configured to be attached to and detached from the apparatus main body of the image forming apparatus 10 by moving it in a substantially horizontal direction (left and right direction in FIG. 1). The attachment / detachment operation of the process cartridge 12 is performed in a state where the user holds the operation lever 12a provided on the process cartridge 12 by hand. Further, an inner cover 12b and a front cover 12c made of plate-like members are provided on the rear side (right side in FIG. 1) of the process cartridge 12 of the apparatus main body so as to be opened and closed. The inner cover 12b and the front cover 12c are locked in a closed state as shown in FIG. 1 in a normal use state. The inner cover 12b and the front cover 12c are opened and closed by rotating around the rotation fulcrums 12d and 12e provided at the lower end portions of the respective members. The inner cover 12b and the front cover 12c are fixed to the closed position shown in FIG. 1 by a lock mechanism (not shown), and are opened in a rotatable state by a release mechanism (not shown). .

  On the other hand, a main feeding unit 13 for feeding a sheet-like recording material P such as recording paper cut to a predetermined size is disposed on the lower side of the apparatus main body. A box-shaped cassette housing 13a constituting the main feeding unit 13 is detachably attached to the apparatus main body. In the main feeding unit 13, sheet-like recording materials P of an appropriate size are stored in a laminated form on the upper surface side of the middle support plate 13b provided inside the cassette housing 13a. The sheet-like recording material P is supported by the middle support plate 13b urged upward by the feeding pressurizing spring 13c, and is held in a state where it is lifted upward. Further, a sensor flag 13d made of a plate-like member bent in a substantially “<” shape is disposed at an upper position on the inner side of the cassette housing 13a so as to swing in the vertical direction. The presence or absence of the sheet-like recording material P in the cassette housing 13a is caused by the bent lower end portion of the sensor flag 13d contacting the uppermost surface position of the sheet-like recording material P stored in the cassette housing 13a by its own weight. Is to be detected.

  Further, a feeding roller 13e formed of a cylindrical member is provided at the front end portion (left end portion in the drawing) of the cassette housing 13a in the paper feeding direction. The feed roller 13e is configured such that the rotational driving force is intermittently connected to the rotation shaft at an appropriate timing by on / off control of an electromagnetic clutch (not shown). The feeding roller 13e performs a feeding operation in a state where the uppermost surface in the stacking direction of the sheet-like recording material P supported by the middle support plate 13b is in contact with the outer peripheral surface from below. It has become. Further, the separation pad (separation member) 13f made of a thin plate member is disposed adjacent to the front side with respect to the front edge (the left edge in the drawing) of the middle support plate 13b in the paper feed direction, and the outer periphery of the feed roller 13e. It arrange | positions so that it may press-contact with respect to a surface from the downward side. The separation pad 13f is attached to the upper surface side of a separation rocking table 13g that is arranged to move up and down at a position directly below the feed roller 13e. The separation rocking base 13g is urged upward by the separation pressure spring 13h, so that the separation pad 13f is always kept in pressure contact with the lower surface side of the feeding roller 13e.

  The sheet-like recording material P stacked in the cassette housing 13a in the main feeding unit 13 passes through the pressure nip portion between the separation pad 13f and the feeding path by the rotation of the feeding roller 13e. It will be sent to 14 side. Further, the sheet-like recording material P is transferred to the photosensitive drum 121 while being appropriately timed by being abutted against the nip portions of the pair of registration rollers 15 and 16 provided in the feeding passage 14. It will be sent to.

  On the other hand, a transfer roller 17 as a contact transfer member is disposed in contact with the surface of the photosensitive drum 121 in the transfer area of the photosensitive drum 121. A transfer bias is applied to the transfer roller 17, and the unfixed toner image formed on the photosensitive drum 121 is electrostatically transferred onto the sheet-like recording material P by the transfer bias. Further, the toner remaining on the photosensitive drum 121 after the transfer is scraped off by the sliding contact force of the cleaning blade 123 disposed so as to come into pressure contact with the surface of the photosensitive drum 121.

  Further, the sheet-like recording material P to which the unfixed toner image has been transferred is fed toward the fixing unit (fixing device) 18. This sheet-like recording material P is introduced into a fixing nip portion N which is a mutual pressure contact portion between a fixing film unit 18a as a heating member and a pressure roller 18b as a pressure member through an inlet guide 18g of the fixing unit 18. . The sheet-like recording material P is nipped and conveyed so as to heat an image (unfixed toner image) formed on the recording material at the fixing nip portion N of the fixing film unit 18a and the pressure roller 18b. Specifically, as shown in FIG. 2 in particular, in the fixing nip portion N, the sheet-like recording material P is formed by the thermal energy applied from the heater 18c included in the fixing film unit 18a and the pressing force by the pressure roller 18b. The upper toner is melted. The molten toner permeates and adheres to the sheet-like recording material P, whereby heat fixing is performed, and an image is formed on the sheet-like recording material P. The sheet-like recording material P on which the image is formed is discharged toward the discharge tray 23 outside the apparatus by the discharge roller 22a and the discharge roller 22b through the nip between the intermediate transfer roller 19a and the intermediate transfer roller 19b.

  However, until the sheet-like recording material P completely passes through the fixing nip portion N, the apparatus main body stops for some reason, and the sheet-like recording material P remains in the fixing nip portion N (hereinafter, fixing error). Sometimes). In this case, if an attempt is made to remove the sheet-like recording material P while the fixing film unit 18a and the pressure roller 18b are in pressure contact, a large force is required to remove the sheet-like recording material P. Alternatively, the sheet-like recording material P may be damaged, and the sheet-like recording material P may remain in the fixing unit 18 and jamming may be difficult.

  Further, when the image forming apparatus 10 is not operated for a long period of time, the pressure film 18a and the pressure roller 18b are in pressure contact with each other for a long period of time, so that the pressure roller 18b may be plastically deformed while maintaining the nip shape. There is.

  Therefore, as shown in FIG. 3, the fixing unit 18 includes a pressure contact mechanism 28 for freely performing pressure contact between the fixing film unit 18a and the pressure roller 18b and releasing the pressure contact.

  That is, the fixing unit 18 includes a fixing film unit 18a as a heating member, a pressure roller 18b as a pressure member, and a pressure contact mechanism 28 that performs pressure contact or pressure release between the fixing film unit 18a and the pressure roller 18b. It is configured. The pressure contact mechanism 28 includes a pressure spring 30, a pressure plate 31, a pressure holding plate 32, and a pressure release cam 33.

  The pressing force of the pressing spring 30 for press-contacting the fixing film unit 18a and the pressing roller 18b is a pressing portion 40 (FIG. 4) that is a contact portion between the pressing plate 31 and the fixing film unit 18a via the pressing plate 31. Reference). Thus, the fixing film unit 18a and the pressure roller 18b are pressed to form a mutual nip portion (fixing nip portion N in FIG. 2).

  As shown in FIGS. 3 to 5, a pressure release cam (eccentric cam) 33 for releasing the pressure contact between the fixing film unit 18 a and the pressure roller 18 b is disposed in the vicinity of the pressure plate 31. The pressure release cam 33, the pressure plate 31, and the pressure holding plate 32 are respectively disposed on both sides in the longitudinal direction of the fixing film unit 18a (the width direction intersecting the recording material conveyance direction). Among these, the pressure release cams 33 on both sides are connected by a pressure release shaft 34, and rotate and stop in synchronization.

  As shown in FIG. 4, in a state where the fixing film unit 18a and the pressure roller 18b are pressed, the pressure release cam 33 and the pressure plate 31 are separated from each other. The pressing force of the pressing spring 30 is applied via the pressing plate 31 to the pressing unit 40 that is a contact portion between the pressing plate 31 and the fixing film unit 18a, and the fixing film unit 18a and the pressing roller 18b are pressed into contact with each other. .

  When releasing the pressure contact between the fixing film unit 18a and the pressure roller 18b, the pressure release cam 33 is rotated so that the circumferential surface of the pressure release cam 33 contacts the pressure plate 31 as shown in FIG. The pressure plate 31 is lifted in a direction that resists the pressure applied by the pressure spring 30. As a result, the pressure plate 31 is separated from the pressure unit 40 of the fixing film unit 18a. By doing so, the pressing force of the pressure spring 30 is not applied to the fixing film unit 18a, and the pressure contact between the fixing film unit 18a and the pressure roller 18b is released.

  As shown in FIGS. 4 and 5, a pressure release sensor flag 35 and a pressure release sensor 36 are arranged on the pressure release cam 33 side on the one axial side of the pressure release cams 33 on both sides. The pressure release sensor flag 35 is in contact with the pressure release cam 33 by the urging force of the pressure release sensor flag spring 37. The pressure release sensor flag 35 is rotated by the rotation of the pressure release cam 33, and the pressure release sensor flag 35 is detected by the pressure release sensor 36, whereby the pressure contact between the fixing film unit 18a and the pressure roller 18b and the pressure contact release are performed. to decide. This determination is made by the control unit 100 by sending a detection signal from the pressure release sensor 36 to a control unit 100 (see FIG. 8) including a CPU that controls the image forming apparatus 10.

  The pressure release cam 33 is rotated by driving a fixing motor M (see FIG. 8). The fixing motor rotates the pressure roller 18b and the intermediate conveyance roller 19a for conveying the sheet-like recording material P toward the discharge port. The intermediate conveyance roller 19 a is provided in the fixing unit 18. The intermediate transport roller 19a is in pressure contact with the intermediate transport roller 19b and sandwiches and transports the sheet-like recording material P. The pressure release cam 33 rotates in the direction opposite to the normal rotation direction so that the pressure roller 18b and the intermediate conveyance roller 19a rotate only in the direction in which the sheet-like recording material P is conveyed toward the discharge port (hereinafter referred to as the normal rotation direction). The rotation direction is regulated by a clutch (not shown) so as to rotate only in the reverse direction).

  The fixing unit 18 is detachably attached to the apparatus main body of the image forming apparatus 10. The fixing unit 18 is configured to be attachable to and detachable from the apparatus main body without using a tool in order to shorten the maintenance work time of the service person.

  Specifically, the image forming apparatus 10 includes a service mode used when a serviceman performs maintenance such as replacement or repair of the fixing unit in addition to a user mode operable by the user. Switchable. Here, the service mode is a non-user mode that cannot be operated by the user. The service mode is switched by performing a special button operation such as input of a personal identification number from the operation unit 103 (see FIG. 8) for operating the image forming apparatus 10.

  Further, the image forming apparatus 10 is configured such that the state of the fixing unit 18 when the pressure contact between the fixing film unit 18a and the pressure roller 18b is released differs between the user mode and the service mode. When the pressure contact between the fixing film unit 18a and the pressure roller 18b is released in the user mode, the pressure contact mechanism 28 in the fixing unit 18 is configured to regulate the removal of the fixing unit 18 from the image forming apparatus main body. On the other hand, when the pressure contact between the fixing film unit 18a and the pressure roller 18b is released in the service mode, the pressure contact mechanism 28 regulates the removal of the fixing unit 18 from the image forming apparatus main body in conjunction with the pressure contact release operation. It is configured to cancel.

  Here, the configuration of the control system in the image forming apparatus will be described with reference to FIG. FIG. 8 is a block diagram schematically showing the configuration of the control system in the image forming apparatus.

  As illustrated in FIG. 8, the control unit 100 includes a CPU (not shown), a ROM 101, and a RAM 102. The operation of each unit of the image forming apparatus is controlled according to a control program stored in the ROM 101 and settings from the operation unit 103 provided in the apparatus main body or an external computer 105.

  The operation unit 103 includes a plurality of keys for setting various functions relating to image formation, a display unit for displaying a setting state, and the like. The operation unit 103 outputs a key signal corresponding to each key operation by the user to the control unit 100 and displays corresponding information on the display unit based on the signal from the control unit 100. The RAM 102 is used as an area for temporarily holding control data and a work area for computations associated with control. An external I / F (external interface) 104 is an interface between the control unit 100 of the image forming apparatus and an external computer 105, and is controlled by the control unit 100.

  Hereinafter, the pressure contact mechanism 28 in the fixing unit 18 that operates as described above will be described in more detail with reference to FIGS.

  The pressure contact mechanism 28 in the fixing unit 18 regulates or removes the removal of the fixing unit 18 from the apparatus body in conjunction with the pressure contact or pressure release operation of the fixing film unit 18a and the pressure roller 18b. It has an engaging part 33a. Here, as the engaging portion 33a, as shown in FIG. 3, an extending portion extending from the pressure release cam 33 toward the device side surface portion 50 is illustrated. As shown in FIGS. 6 and 7, the engaging portion 33 a engages with or engages with a groove (engaged portion) 50 a provided in the device side surface portion 50 by the rotation of the pressure release cam 33. Rotate to release. In the fixing unit 18, when the engaging portion 33 a is engaged with the groove 50 a of the device side surface portion 50, removal of the fixing unit 18 from the apparatus main body is restricted (engagement position). Then, by releasing the engagement between the engagement portion 33a and the device side surface portion 50, the restriction on the removal of the fixing unit 18 from the device main body is released (engagement release position).

  In the state where the fixing film unit 18a and the pressure roller 18b are in pressure contact, the pressure release cam 33 of the pressure contact mechanism 28 is in a position (pressure contact) where the engagement portion 33a is engaged with a groove 50a provided in the apparatus side surface portion 50. Position). In the operation of releasing the pressure contact, the pressure release cam 33 of the pressure contact mechanism 28 moves the engagement portion 33a to the engagement position, or the engagement portion 33a. The position is switched to the second press release position that moves to the disengagement position.

  Here, with reference to FIG. 9, the relationship between the operation control of the pressure contact mechanism 28 in the operation control by the control unit 100 and the removal restriction or restriction release of the fixing unit 18 will be described. FIG. 9 is a flowchart showing the relationship between the operation control of the pressure contact mechanism 28 and the removal restriction or restriction release of the fixing unit 18.

  As described above, the fixing motor M is used to drive the pressure release cam 33 as well as the pressure roller 18b and the intermediate conveyance roller 19a. First, in S1, the control unit 100 determines whether the setting from the operation unit 103 is the user mode or the service mode.

  In the user mode, when a fixing error occurs or when the power of the image forming apparatus 10 is turned off (hereinafter, when the power is turned off) (S2), the fixing motor M (see FIG. 8) rotates reversely and the pressure release cam 33 is shown in FIG. From the position shown in FIG. 5 to the position shown in FIG. 5 in the direction of arrow A (S3). As a result, the pressure release cam 33 starts to release the pressure contact between the fixing film unit 18a and the pressure roller 18b. When the pressure release between the fixing film unit 18a and the pressure roller 18b is completely completed, the pressure release sensor flag 35 abutted on the pressure release cam 33 shields the pressure release sensor 36 (S4), and when a second elapses ( In step S5, the fixing motor stops and the state shown in FIG. 6 is obtained (S6).

  In the state shown in FIG. 6, the engaging portion 33 a provided on the pressure release cam 33 is engaged with the groove 50 a of the device side surface portion 50, and the fixing unit 18 is removed from the device side surface portion 50 in the direction (arrow B direction). It regulates against it. Therefore, the fixing unit 18 cannot be removed from the apparatus main body. That is, in the user mode, the pressure release cam 33 is switched to the first pressure release position where the engagement portion 33a moves to the engagement position shown in FIG. ing.

  On the other hand, in the service mode, when a fixing error occurs or when the power of the image forming apparatus 10 is turned off (S7), the fixing motor M (see FIG. 8) rotates reversely and the pressure release cam 33 is moved from the position shown in FIG. Rotate to the position in the direction of arrow A (S8). As a result, the pressure release cam 33 starts to release the pressure contact between the fixing film unit 18a and the pressure roller 18b. When the pressure contact between the fixing film unit 18a and the pressure roller 18b is completely released, the pressure release sensor flag 35 abutted on the pressure release cam 33 shields the pressure release sensor 36 (S9), and further b seconds (however, a <B) After a lapse (S10), the fixing motor (not shown) is stopped and the state shown in FIG. 7 is obtained (S11).

  In the state shown in FIG. 7, the engagement portion 33 a provided on the pressure release cam 33 is disengaged from the groove 50 a of the device side surface portion 50, and the fixing unit 18 is removed from the device side surface portion 50 (arrow B). Direction) has been lifted. Therefore, the fixing unit 18 can be removed from the apparatus main body. That is, in the service mode, during the operation of releasing the pressure contact, the pressure release cam 33 is switched to the second pressure release position where the engagement portion 33a is moved to the engagement release position shown in FIG. It has become.

  As described above, according to the present embodiment, since the press contact mechanism 28 also functions to restrict or release the fixing unit 18, the fixing unit 18 that can be replaced without using a tool is provided. It can be realized with a simple and low-cost configuration without increasing the number of parts.

  In the user mode, even if the pressure contact mechanism 28 releases the pressure contact between the fixing film unit 18a and the pressure roller 18b, the fixing unit 18 is restricted from being removed, so that the user can be prevented from removing the fixing device. Can be protected. Furthermore, since removal of the fixing device by the user is restricted, it is not necessary to provide a protective member or the like for protecting the user in the fixing unit, and accordingly, a fixing unit having a simple and low cost configuration can be realized. On the other hand, in the service mode (non-user mode), the pressure contact mechanism 28 releases the pressure contact between the fixing film unit 18a and the pressure roller 18b, and the restriction on the removal of the fixing unit 18 is also released. Thus, the maintenance work of the fixing unit 18 by the service person is facilitated.

[Other Embodiments]
In the above-described embodiment, the configuration of performing the operation of moving to the first pressure contact release position or the operation of moving to the second pressure contact release position at the time of a fixing error or when the power is turned off is illustrated, but the present invention is limited to this. It is not a thing. For example, a mode in which a special key operation is performed from the operation unit (not shown) of the image forming apparatus and an operation for forcibly moving to the first pressure release position or an operation for moving to the second pressure release position can be selected. The present invention can be similarly applied to those provided with the above.

  In the above-described embodiment, the configuration in which the time from when the pressure release sensor flag 35 shields the pressure release sensor 36 to when the fixing motor (not shown) is stopped is illustrated in the user mode and the service mode. It is not limited to this. For example, a sensor that detects the position of the engaging portion 33a of the pressure release cam 33 may be provided separately, and a fixing motor (not shown) may be stopped based on a detection signal from the sensor.

  In the above-described embodiment, the configuration in which the engaging portion 33a of the pressure contact mechanism 28 of the fixing unit 18 is engaged with or released from the groove (engaged portion) 50a provided in the apparatus main body is illustrated. It is not limited to this. Specifically, the engaged portion provided in the apparatus main body may not be a groove. Alternatively, it is not always necessary to provide a groove in the apparatus main body. It is good also as a structure which the engaging part which a press-contacting mechanism has engages or disengages directly with an apparatus main body. For example, in the above-described embodiment, the configuration in which the engaging portion is provided on the eccentric cam that acts on the sensor flag is illustrated. However, the engaging portion is provided separately from the eccentric cam and interlocked with the operation of the eccentric cam. It is good also as a structure which moves a position and engages or disengages directly with an apparatus main body (for example, a part of flame | frame etc.).

  In the above-described embodiment, the image heating apparatus that can be attached to and detached from the apparatus main body of the image forming apparatus is exemplified as a fixing apparatus that fixes an unfixed image on a recording material. However, the present invention is not limited to this. For example, another image heating device such as a gloss increasing device that increases the gloss of the image by heating the image fixed on the recording material may be used. Further, the configuration in which the image forming apparatus has one image heating apparatus has been described as an example, but the present invention is applied to the image heating apparatus even if the image forming apparatus has a plurality of image heating apparatuses. Thus, the same effect can be obtained.

  In the above-described embodiment, the image forming apparatus in which one process cartridge is detachable is illustrated. However, the number of process cartridges to be used is not limited to this, and may be set as appropriate.

  In the above-described embodiment, the printer is exemplified as the image forming apparatus, but the present invention is not limited to this. For example, the image forming apparatus may be another image forming apparatus such as a copying machine or a facsimile machine, or another image forming apparatus such as a multi-function machine combining these functions. Further, an image forming apparatus that uses a recording material carrier and sequentially superimposes and transfers the toner images of the respective colors on the recording material carried on the recording material carrier. Alternatively, an image forming apparatus that uses an intermediate transfer member, sequentially transfers toner images of respective colors on the intermediate transfer member, and collectively transfers the toner images carried on the intermediate transfer member onto a recording material. Also good. The same effect can be obtained by applying the present invention to a detachable image heating apparatus used in these image forming apparatuses.

  In the above-described embodiment, the film unit is used as the heating member and the heater is used as the heat source. However, the present invention is not limited to this. For example, the heating member may be a roller or a belt, and the heat source may be induction heating. Moreover, although the example which used the roller for the pressurization member was shown, it is not limited to this. For example, the pressure member may be a belt. Even with a detachable image heating apparatus using these members, the same effects can be obtained by applying the present invention.

N: Fixing nip 10: Image forming apparatus 18: Fixing unit 18a: Fixing film unit 18b ... Pressure roller 18c ... Heating heater 18g ... Inlet guide 19a ... Intermediate conveyance roller 19b ... Intermediate conveyance roller 28 ... Pressure contact mechanism 30 ... Pressure Spring 31 ... Pressure plate 32 ... Pressure holding plate 33 ... Pressure release cam 33a ... Engagement part 50 ... Device side face part 50a ... Groove

Claims (5)

Removably attached to the main body of the image forming apparatus that forms an image on the recording material, and the recording material is nipped and conveyed so as to heat the image formed on the recording material at the press contact portion of the heating member and the pressure member. An image heating device,
A pressure contact mechanism for performing pressure contact or pressure contact release between the heating member and the pressure member;
The pressure contact mechanism engages with the apparatus main body in conjunction with the operation of pressing or releasing the pressure contact between the heating member and the pressure member, or an engagement position for restricting removal of the image heating apparatus from the apparatus main body. An image heating apparatus comprising: an engagement portion that moves to an engagement release position that releases the engagement with the apparatus main body and releases the restriction on the removal of the image heating apparatus from the apparatus main body.   In the operation of releasing the pressure contact between the heating member and the pressure member, the pressure contact mechanism moves the engagement portion to the engagement position, and releases the engagement portion from the engagement portion. The image heating apparatus according to claim 1, wherein the image heating apparatus is provided so as to be switchable to a second press release position that moves to a position. In an image forming apparatus that detachably mounts an image heating device that sandwiches and conveys a recording material to heat an image formed on the recording material at a pressure contact portion between the heating member and the pressure member, and forms an image on the recording material,
The image heating apparatus has a pressure contact mechanism for performing pressure contact or pressure contact release between the heating member and the pressure member,
The pressure contact mechanism engages with the apparatus main body of the image forming apparatus and regulates the removal of the image heating apparatus from the apparatus main body in conjunction with the operation of pressing or releasing the pressure contact between the heating member and the pressure member. An image forming apparatus comprising: an engagement portion that moves to an engagement position or an engagement release position that releases the engagement with the apparatus main body and releases the restriction on the removal of the image heating apparatus from the apparatus main body. .   In the operation of releasing the pressure contact between the heating member and the pressure member, the pressure contact mechanism moves the engagement portion to the engagement position, and releases the engagement portion from the engagement portion. The image forming apparatus according to claim 3, wherein the image forming apparatus is switchable to a second press release position that moves to a position. The image forming apparatus can be switched between a user mode operable by the user and a non-user mode not operable by the user,
The image heating device switches the pressure contact mechanism to the first pressure release release position in the user mode during the operation of releasing the pressure contact between the heating member and the pressure member, and in the non-user mode. The image forming apparatus according to claim 4, wherein the pressure contact mechanism is switched to the second pressure release position.

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