JP5393101B2 - Image heating device - Google Patents

Description

  The present invention relates to an image heating apparatus in which a belt unit in which a belt member is integrally assembled with a plurality of support rotating bodies can be removed from a base member, and more specifically, a detection member that is disposed on the base member side and detects an edge of the belt member. Concerning structure.

  An image heating apparatus in which at least one of a pair of rotating members constituting a toner image fixing nip is configured by a steering-controlled belt member (fixing belt or pressure belt) has been put into practical use. Hereinafter, an image heating apparatus that has the same configuration as that of the fixing device and adjusts the surface gloss of the fixed or semi-fixed toner image is referred to as an image heating device including the fixing device.

  Patent Document 1 discloses an image heating apparatus that forms a fixing nip by pressing a fixing belt and a pressure belt.

  Patent Document 2 discloses an image heating apparatus that forms a fixing nip by pressing a fixing roller and a pressure belt. Here, the inclination of the detection member brought into contact with the rotating belt member is detected, and the position of the belt member in the longitudinal direction of the support rotating body is measured. And the deviation of the belt member in the longitudinal direction of the support rotator is dynamically corrected by performing the steering control that changes the inclination of the support rotator according to the measurement result.

JP 2004-341346 A JP-A-11-227930

  In order to reduce the downtime of the image forming apparatus due to the replacement of the belt member, the belt member may be assembled into a belt unit including a plurality of support rotating bodies that span the belt member and exchanged integrally. preferable.

  Further, in order to facilitate the belt unit replacement work, the base member is moved from the operation position in the housing to a predetermined work position by the drawer mechanism in a state where the belt unit is attached to the base member of the image heating apparatus. It is preferable to be pulled out integrally.

  Further, when removing the belt unit from the base member, the belt edge sensor is preferably disposed on the base member side so that the wiring of the belt edge sensor including the detection member is not required.

  In the case where the image heating apparatus is configured in this way, it has been found that the belt member may be damaged due to the end of the belt member coming into contact with the detection member in the process of removing and reattaching the belt unit from the base member. .

  As shown in Patent Document 2, when the detection member is spring-biased toward the belt edge, the detection member that loses support by the edge of the belt member at the moment when the belt unit is removed from the base member is the belt member. Invades the inside of the edge. At this time, the opposing belt member may be scratched. If a new belt unit is attached to the base member in this state, the tip of the detection member pierces the belt member, and the edge of the belt member cannot be normally detected.

  In view of this, a configuration has been proposed in which an operation lever is provided on the base member side and a serviceman performs a lever operation to retract the belt edge sensor to the outside of the edge that does not interfere with the belt member.

  However, if the service person forgets to operate the lever, the belt member cannot be prevented from being damaged when the new belt unit is attached to the base member as it is. If the lever is forgotten to be returned after normal replacement work, normal steering control performed by detecting the edge of the belt member after the image heating device is started up is not executed.

  In view of this, a mechanism has been proposed in which the operation lever is interlocked with the belt unit, and the detection member automatically retracts / returns when the belt unit is removed / attached. However, in this case, since the detection member is still in contact with the edge of the belt member when the detachment movement starts, there is a possibility that the belt edge is caught by the detection member. Since the detection member begins to contact the edge of the belt member at an earlier stage than positioning the belt unit to the normal position, the detection member can rub against the edge of the belt member and make a dent or crease in the subsequent movement. There is sex. Accordingly, the detection member cannot be retracted / returned by reliably avoiding damage to the belt member.

  In addition, when the entire belt edge sensor including the detection member is moved between the operation position and the work position, the movement mechanism is increased in size and a large interference space for moving the belt edge sensor is provided. I need it. For this reason, there is a problem in reducing the cost of parts of the image forming apparatus and reducing the overall configuration.

  An object of the present invention is to provide an image heating apparatus that retracts a detection member to a position that does not interfere with the belt member before starting to remove the belt unit, and returns the detection member to a normal detection position after the belt unit has been attached. It is said.

An image heating apparatus according to the present invention includes a belt unit assembled so that a belt member supported by a plurality of support rotating bodies can be integrally replaced with the plurality of support rotating bodies, and the belt unit is detachably attached. A base member configured to be configured, a detection member that detects an edge of the belt member to perform steering control of the belt member, and a predetermined movement with respect to the base member that supports the detection member is possible A support member, a spring member for biasing the support member so that the detection member abuts against an edge of the belt member, and the belt unit being removed from the base member in a normal position. It can not, said from the base member by leave from the normal position by bereaved removal of the belt unit Berutoyu And mechanical components it is possible to remove the Tsu bets, by contacting said mechanical parts to the support member with the operation to leave the said normal position, said edge of said sensing member against the urging said spring The detection member is forcibly separated from the normal detection position and moved to a position outside the edge of the belt member, and the mechanism member is brought into contact with the support member in accordance with the operation of positioning the mechanical component to the normal position. A contact member that is released to return the detection member to the normal detection position.

  In the image heating apparatus of the present invention, the detection member moves from the normal detection position to the outside of the edge of the belt member that does not interfere with the belt member in conjunction with the movement of the mechanical component that must be moved out before removing the belt unit from the base member. evacuate. Then, after the belt unit is attached to the base member, the detection member returns to the normal detection position where the edge of the belt member is detected in conjunction with the movement of the mechanical component positioned at the normal position.

  Therefore, the detection member can be retracted to a position where it does not interfere with the belt member before starting to remove the belt unit, and the detection member can be returned to the normal detection position after the belt unit has been attached.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The present invention replaces part or all of the configuration of the embodiment as long as the detection member automatically retracts to the outer position of the belt member in conjunction with the preliminary operation before removing the belt unit from the base member. Other embodiments replaced with a typical configuration can also be implemented.

  Therefore, the present invention is not limited to the image heating apparatus in which the pressure belt is pressed against the fixing belt, and the image heating apparatus in which the pressure belt is pressed against the fixing roller, or the image heating apparatus in which the pressure roller is pressed against the fixing belt.

  The image forming apparatus on which the image heating apparatus is mounted is not limited to an image forming apparatus that uses an intermediate transfer belt, but can also be implemented by an image forming apparatus that transfers a toner image to a recording material carried on a recording material conveyance belt. Not only a one-drum type in which one photosensitive drum is arranged along the belt member, but also a tandem type in which a plurality of photosensitive drums are arranged.

  In the present embodiment, only main parts related to toner image formation / transfer will be described. However, the present invention includes a printer, various printing machines, a copier, a fax machine, a composite machine, in addition to necessary equipment, equipment, and a housing structure. It can be implemented in various applications such as a machine.

  In addition, about the general matter of the image forming apparatus shown by patent document 1, 2, illustration is abbreviate | omitted and the overlapping description is abbreviate | omitted. In the description, the reference symbols in parentheses shown in the configuration names used in the claims are examples for helping understanding of the invention, and the invention is limited to combinations of the corresponding configurations in the embodiments. It is not intended.

<Image forming apparatus>
FIG. 1 is an explanatory diagram of a configuration of the image forming apparatus according to the first embodiment.

  As illustrated in FIG. 1, the image forming apparatus 100 according to the first embodiment is a full-color printer in which image forming units 200 </ b> Y, 200 </ b> M, 200 </ b> C, and 200 </ b> K are arranged in a straight section of the intermediate transfer belt 25. In the case structure of the image forming apparatus 100, in addition to the image forming units 200Y, 200M, 200C, and 200K, various devices necessary for the image forming process such as the intermediate transfer unit 30 and the fixing device 27 are unitized and held. Has been.

  In the image forming unit 200Y, a yellow toner image is formed on the photosensitive drum 20Y and is primarily transferred to the intermediate transfer belt 25. In the image forming unit 200M, a magenta toner image is formed on the photosensitive drum 20M, and is primarily transferred onto the yellow toner image on the intermediate transfer belt 25. In the image forming units 200C and 200K, a cyan toner image and a black toner image are formed on the photosensitive drums 20C and 20K, respectively, and similarly, the toner images on the intermediate transfer belt 25 are overlapped with each other and sequentially primary transferred.

  The four-color toner images carried on the intermediate transfer belt 25 are conveyed to the secondary transfer portion T2, and are secondarily transferred collectively to the recording material P that is superimposed on the intermediate transfer belt 25 and sandwiched and conveyed by the secondary transfer portion T2. The The recording material P on which the toner image is secondarily transferred by the secondary transfer portion T2 is heated and pressurized by the fixing device 27, and the toner image is fixed on the surface, and then discharged to the outside.

  The recording material P pulled out one by one from the cassette waits at the registration roller 28 and is sent out to the secondary transfer portion T2 in time with the toner image on the intermediate transfer belt 25.

  The image forming units 200Y, 200M, 200C, and 200K are configured substantially the same except that the colors of toner used in the attached developing devices 23Y, 23M, 23C, and 23K are different from yellow, magenta, cyan, and black. Hereinafter, the image forming unit 200Y will be described, and the other image forming units 200M, 200C, and 200K will be described by replacing “Y” at the end of the reference code with “M”, “C”, and “K”.

  In the image forming unit 200Y, a charging device 21Y, an exposure device 22Y, a developing device 23Y, and a primary transfer device 24Y are arranged around the photosensitive drum 20Y.

  The photosensitive drum 20Y is composed of a metal cylinder having a negatively charged photosensitive layer formed on the surface thereof, and rotates in the direction of the arrow at a predetermined process speed.

  The charging device 21Y rotates the charging roller in pressure contact with the photosensitive drum 20Y, and applies an oscillating voltage obtained by superimposing an AC voltage on the DC voltage to the charging roller, so that the surface of the photosensitive drum 20Y has a uniform negative polarity potential. Charge.

  The exposure device 22Y scans the scanning line image data obtained by developing the image data with a polyhedral mirror, and writes an electrostatic image of the image on the surface of the charged photosensitive drum 20Y.

  The developing device 23Y holds the negatively charged toner on the developing sleeve and rubs the photosensitive drum 20Y, and applies an oscillating voltage in which an alternating voltage is superimposed on the negative direct current voltage to the developing sleeve, thereby developing the photosensitive drum 20Y. The electrostatic image is reversely developed.

  The primary transfer device 24 </ b> Y presses the primary transfer roller against the photosensitive drum 20 </ b> Y via the intermediate transfer belt 25 to form a primary transfer portion of the toner image between the photosensitive drum 20 </ b> Y and the intermediate transfer belt 25. By applying a positive DC voltage to the primary transfer roller, the toner image charged to the negative polarity and carried on the photosensitive drum 20 </ b> Y is primarily transferred to the intermediate transfer belt 25.

  The secondary transfer device 26 presses the secondary transfer roller 26a against the opposing roller 29 via the intermediate transfer belt 25 to form a secondary transfer portion T2 between the intermediate transfer belt 25 and the secondary transfer roller 26a. . The secondary transfer portion T2 sandwiches and conveys the recording material P while being superimposed on the toner image on the intermediate transfer belt 25. The toner image charged negatively and carried on the intermediate transfer belt 25 is secondarily transferred to the recording material P by applying a positive voltage to the secondary transfer roller 26a.

<Fixing device>
FIG. 2 is an explanatory diagram of a configuration of the fixing device, FIG. 3 is a perspective view of an assembly structure of the fixing device, and FIG. 4 is an explanatory diagram of a drawer structure of the fixing device.

  As the process speed increases, the time for the recording material to pass through the fixing nip decreases. Therefore, in order to efficiently apply heat to the recording material, it is necessary to increase the length of the fixing nip in the recording material conveyance direction. There is. In a fixing device using a pair of rollers, if the length of the fixing nip in the recording material conveyance direction is increased, the diameter of the roller increases, leading to an increase in the size of the fixing device itself.

  Therefore, a belt heat generation method that can obtain a sufficient nip width while adapting to a reduction in size and speed of the apparatus as compared with the roller fixing method is adopted. In this method, even if the process speed is increased, the time for the recording material to pass through the fixing nip becomes longer, and the amount of heat given to the recording material increases.

  As shown in FIG. 3 with reference to FIG. 2, the fixing device 27 includes a fixing belt module 300, a pressure belt module 301, and a frame body 302. The pressure belt 200 of the pressure belt module 301 is brought into pressure contact with the fixing belt 220 of the fixing belt module 300 to form a fixing nip for nipping and conveying the recording material while heating.

  The fixing belt module 300 is fixed to the frame body 302, and the pressure belt module 301 is attached to the frame body 302 so as to be able to move up and down with respect to the fixing belt module 300.

  The fixing belt module 300 includes an endless fixing belt 220 that is a main part of a heating body, and the fixing belt 220 rotates between both the fixing roller 221 and the fixing tension roller 222 and rotates. To do.

  The fixing belt 220 can be appropriately selected as long as it can generate heat by the induction heating coil 224 and has heat resistance. Here, a magnetic metal layer such as a nickel metal layer or a stainless steel layer having a thickness of 100 μm, a width of 380 mm, and a circumferential length of 200 mm is coated with silicon rubber having a thickness of 500 μm and a surface layer is coated with a PFA tube. .

  When an alternating current is passed through the induction heating coil 224, magnetic field lines are generated around the coil, and an eddy current is generated in the metal layer of the fixing belt 220. The eddy current is changed to Joule heat by the resistance of the metal layer, and the metal layer generates heat. Let As a result, the fixing belt 220 is heated.

  Inside the fixing belt 220, a thermistor (not shown) as temperature detecting means is disposed, and the temperature control unit 101 detects the temperature of the inner surface of the fixing belt 220 based on an output signal of the thermistor. Heating control by the induction heating coil 224 is set so that the temperature of the inner surface of the fixing belt 220 becomes 180 ° C. by the temperature control unit 101.

  The fixing roller 221 is formed by integrally forming a heat-resistant silicone rubber elastic layer on a core metal surface layer in which the outer diameter of a solid stainless steel material is 19 mm. The fixing roller 221 is disposed on the exit side in the fixing nip region between the fixing belt 220 and the pressure belt 200, and the heat-resistant silicone rubber elastic layer on the surface is elastically deformed by the pressure in the direction in pressure contact with the pressure roller 201. doing.

  The fixing tension roller 222 applies a tension set to 120 N so that the belt tension of the fixing belt 220 is always kept optimal. The fixing tension roller 222 is a hollow roller made of a stainless material and having an outer diameter of φ20 and an inner diameter of φ16.

  A fixing pad 223 made of a stainless material is provided inside the fixing belt 220 on the inlet side in the fixing nip region between the pressure belt 200 and the fixing belt 220, that is, on the upstream side of the fixing roller 221. Yes. The fixing pad 223 is pressed against the inner surface of the fixing belt 220 with a set pressure 400N toward the pressure pad 204 on the pressure belt module 301 side.

  The pressure belt module 301 has an endless pressure belt 200 that is a main part of a pressure body, and the pressure belt 200 is between the pressure roller 201 and the pressure tension roller 202. Rotated by being swung over.

  The pressure roller 201 is a hollow rod made of stainless steel (SUS), is formed with an outer diameter of about 21 mm and an inner diameter of about 19 mm, and is disposed on the exit side in the fixing nip region between the pressing belt 200 and the fixing belt 220. Has been.

  The pressure tension roller 202 is a hollow roller having an outer diameter of approximately 22 mm and an inner diameter of approximately 20 mm made of a stainless material, and functions as a roller that constantly applies an optimum tension to the pressure belt 200. Both end portions of the pressure tension roller 202 are urged outward by a tension urging spring disposed inside the bearing portion 205 so as to maintain a tension of 100 N on the pressure belt 200.

  Inside the pressure roller 201, a heater 207 as a heating element is mounted to heat the pressure belt 200 from the inside. Here, a halogen heater is used as the heater 207, but other heaters can be used as long as they can be used as a heat source.

  The temperature of the pressure belt module 301 is adjusted by the temperature control unit 101 so that the surface temperature of the pressure belt 220 becomes 100 ° C. As temperature detection means, contact type thermistors 308 a and 308 b are disposed in contact with the outside of the image area on the outer peripheral surface of the pressure belt 200, and the non-contact type thermistor 308 c is opposed to substantially the center in the longitudinal direction of the pressure belt 220. Arranged. Based on the output signals of the thermistors 308a, 308b, and 308c, the temperature control unit 101 detects the temperature of the outer peripheral surface of the pressure belt 200, and the heating control heater 207 controls the heating so that the temperature of the outer peripheral surface becomes 100 ° C. Is done.

  The pressure pad 204 is made of silicon rubber and corresponds to the inlet side in the fixing nip region formed between the pressure belt 200 and the fixing belt 300, that is, the upstream side of the pressure roller 201. Is provided inside. The pressure pad 204 is pressed toward the fixing pad 223 with a set pressure of 400 N, and forms an upstream region of the fixing nip between the fixing belt 220 and the pressure belt 200.

  The pressure belt module 301 is supported by a pressure unit frame 208 that can be attached to and detached from the frame body 302. A pressure spring 209 and a pressure adjusting screw 210 are disposed upstream of the pressure unit frame 208. By appropriately tightening the pair of pressure adjusting screws 210, the amount of contraction of the pressure spring 209 is adjusted to optimize the pressure.

  As the pair of pressure cams 304 disposed on the frame 302 rotate, the pressure belt module 301 moves up and down, and the fixing belt 220 and the pressure belt 200 are pressed / separated to form a fixing nip / To release. The pressure unit frame 208 of the pressure belt module 301 rotates around the rotation shaft 303. Accordingly, the pressure roller 201 and the pressure pad 204 are brought into pressure contact with the fixing roller 221 and the fixing pad 223 through the fixing belt 220 and the pressure belt 200, respectively. As a result, the surface silicon rubber layers of the fixing belt 220 and the pressure belt 200 are elastically deformed to form a fixing nip that is continuous in the conveying direction. In the process in which the recording material to which the toner image is transferred passes through the fixing nip, the toner image is fixed on the recording material.

  The recording material on which the toner image is fixed is discharged from the fixing device 27 through the post-fixing paper discharge unit 320. The post-fixing paper discharge unit 320 can rotate about the rotation hole 325 with respect to the frame body 302, and can be opened and closed from the fixing device 27.

  The post-fixing paper discharge unit 320 includes a separation sheet metal 322 as separation means. The separation sheet metal 322 is disposed so as to be close to the fixing belt 220 of the fixing belt module 300 when the post-fixing paper discharge unit 320 is rotated to the normal position. A sheet discharge guide 326 is disposed below the separation sheet metal 322.

  The post-fixing paper discharge unit 320 is provided with a pair of paper discharge rollers including a paper discharge upper roller 323 and a paper discharge lower roller 324, and the recording material separated from the fixing belt 220 by the separation metal plate 322 is conveyed in the paper discharge direction. To do.

  The separation means may be a non-contact separation claw type or a contact-type separation means.

  As shown in FIG. 4, the fixing device 27 is supported by a slide guide 103 as a pulling mechanism, and can be pulled out integrally to a predetermined work position on the front side of the image forming apparatus 100. In the state where the fixing device 27 is pulled out to the work position on the front side, the fixing belt module 300 and the pressure belt module 301 are removed from the frame body 302 as shown in FIG.

<Steering control>
FIG. 5 is an explanatory diagram of a configuration of a belt detection unit that detects a pressure belt, and FIG. 6 is an explanatory diagram of a steering operation of the pressure belt. In a belt-type fixing device, a belt member is stretched over and supported by a plurality of support rotating bodies, and tension is applied to the belt member. In this case, the belt member is displaced due to the deviation of the axes of the plurality of rotating bodies. For this reason, belt position detecting means for correcting the belt deviation and belt deviation correcting means are required.

  As shown in FIG. 3, the belt detection unit 500 is disposed at a position corresponding to the edge of the pressure belt 200 on the front side of the frame body 302. FIG. 5 illustrates the belt position detection unit 500 in a form in which the pressure belt 200 is looked up from below the frame body 302 in FIG. 3.

  As shown in FIG. 5, the belt detection unit 500 detects the rotation angle of the belt position detection flag 501 that rotates following the position of the edge of the pressure belt 200 by the photosensors 503a and 503b.

  A belt position detection flag 501 that can rotate around the flag rotation shaft 505 and a belt position detection arm 502 that can rotate around the arm rotation shaft 506 are disposed on the base plate 510. The belt position detection flag 501 and the belt position detection arm 502 are engaged with each other by a pin 502 b fixed to the belt position detection arm 502.

Since the belt position detection flag 501 is spring-biased by an arm biasing spring 503, which is an example of a spring member, to apply a tensile force in the direction of arrow R3, the belt position detection flag 501 will rotate around the flag rotation shaft 505 in the direction of arrow R4. And The arm biasing spring 503 applies a tensile force to the belt position detection flag 501 with a force of 1N.

  Along with this, the belt position detection arm 502 tries to rotate in the direction of the arrow R5 around the arm rotation shaft 506, so that the belt detection pin 502a fixed to the belt position detection arm 502 is attached to the edge of the pressure belt 200. Always abut against. As a result, the belt position detection flag 501 rotates following the movement of the pressure belt 200 in the arrow R6 direction. Then, the notches 501a and 501b provided in the belt position detection flag 501 are positioned at rotational positions corresponding to the positions of the edges of the pressure belt 200 detected by the belt detection pin 502a.

  Photosensors 503a and 503b for detecting the notches 501a and 501b are arranged on the base plate 510. As shown in Table 1, the steering control unit 102 determines where the position of the pressure belt 200 is currently according to the ON / OFF pattern of the photosensors 503a and 503b that detect the notches 501a and 501b. Then, the rotation of the stepping motor 600 is controlled to change the inclination of the pressure tension roller 202, and the pressure belt 200 is steering-controlled.

  As shown in FIG. 6 with reference to FIG. 5, when the pressure belt 200 approaches the front side, the belt detection pin 502a is pushed to the front side, and the belt position detection unit 500 detects the offset position F. . The steering control unit 102 controls the rotation of the stepping motor 600 to rotate the worm gear 601, and rotates the bearing 205 on the front side of the pressure tension roller (202: FIG. 2) around the central axis of the pressure roller 201. Move. As a result, the moving direction of the pressure belt 200 is reversed, and the pressure belt 200 moves toward the back side.

  When the pressure belt 200 approaches the back side, the belt position detection unit 500 detects the offset position R, and the steering control unit 102 rotates the worm gear 601 to front the pressure tension roller (202: FIG. 2). Rotate side down. As a result, the moving direction of the pressure belt 200 is reversed, and the pressure belt 200 moves toward the front side.

  By such repeated control operation, the pressure belt 200 continues to meander, and the shift correction operation of the pressure belt 200 is performed in an amplitude range of about 2 mm. In the fixing belt module 300, the same misalignment correction operation is performed.

<Interlocking mechanism>
As shown in FIG. 3, the belt unit (301) is assembled so that the belt member (200) supported by the plurality of support rotating bodies can be integrally replaced with the plurality of support rotating bodies.

  As shown in FIG. 5, the detection member (502a) detects the edge of the belt member in order to perform the steering control of the belt member (200). As shown in FIG. 3, the base member (302) is configured such that the belt unit (301) is detachably attached thereto. As shown in FIG. 2, the belt unit (301) cannot be removed from the base member (302) when the mechanical component (320) is positioned at the normal position.

  In such an image heating apparatus, the following can occur during assembly and replacement of the belt module. Since the detection member is brought into contact with the belt member by spring bias, when the belt module is pulled out from the frame of the fixing device, the leading end of the detection member enters the inside of the belt member. When a new belt unit is inserted in such a state, the detection member may damage the belt member.

  In order to avoid this problem, it is conceivable to use an optical non-contact sensor as a belt member detection means. However, the periphery of the fixing device is a high temperature atmosphere, which is not preferable from the viewpoints of durability and reliability of the sensor and cost.

  In the first embodiment, the interlocking mechanism (420) controls the retracting and returning of the detection member (502a). Prior to the removal of the belt unit (301), the detection member (502a) is moved from the normal detection position to the outer position of the edge of the belt member (200) in conjunction with the movement of moving the mechanical component (320) out of the normal position. Move. Further, the detection member (502a) is returned to the normal detection position in conjunction with the movement of positioning the mechanical component (320) to the normal position.

  The detection member (502a) is spring-biased so as to contact the edge of the belt member (200) via a support member (501) supported so as to be able to move (rotate) with respect to the base member (302). Has been. The interlocking mechanism (420) abuts against the support member (501) with the operation of moving the mechanical component (320) away, thereby forcibly separating the detection member (502a) against the spring bias. (326a). The contact of the contact member (326a) with the support member (501) is released with the operation of positioning the mechanical component (320).

  The mechanical component (320) includes a discharge rotating body (323, 324) that conveys the recording material discharged from the heating nip of the recording material formed by pressing the rotating body (220) against the belt member (200). It is a rotating body unit. However, a rotating body unit including a rotating body that presses the belt member (200) to form a recording material heating nip may be used.

  In the second embodiment, the interlocking mechanism (511) controls the retracting and returning of the detection member (502a). The detection member (502a) is moved from the normal detection position to the outer position of the edge of the belt member (200) in conjunction with the movement of the base member (302) pulled out from the normal position using the drawer mechanism (103). Further, the detection member (502a) is returned to the normal detection position in conjunction with the movement of positioning the base member (302) to the normal position by using the drawer mechanism (103).

<Example 1>
FIG. 7 is a front view of the fixing device showing a normal position and a retracted position of the paper discharge unit after fixing, and FIG. 8 is a front view of the fixing device with the fixing belt module and the pressure belt module removed from the frame. FIG. 9 is an explanatory diagram of the operation of the interlocking mechanism, and FIG. 10 is an explanatory diagram of the operation of the belt detection unit accompanying the operation of the interlocking mechanism.

  As shown in FIG. 7A, the fixing belt module 300 is assembled on the frame 302 of the fixing device 27 after the pressure belt module 301 is assembled.

  As shown in FIG. 3, the rotating shaft 303 is assembled after the outer surface of the attachment portion 211 of the pressure belt module 301 is restrained by the U-shaped guide 311 of the frame 302 and moved vertically. It has been. Thereafter, the fixing belt module 300 is fixed to the frame 302 by overlapping and pinning the pin holes 232 and 234 of the fixing belt module 300 and the mounting holes 231 and 233 of the frame 302.

  When replacing the pressure belt module 301, it is necessary to remove the fixing belt module 300 from the frame body 302 in order to extract the pressure belt module 301 from above the frame body 302. In order to remove the fixing belt module 300, it is necessary to open the post-fixing paper discharge unit 320 as shown in FIG.

  As shown in FIG. 7B, the fixing belt module 300 and the pressure belt module 301 can be removed by manually operating the lever 320a to retract the post-fixing paper discharge unit 320 to the outside and retract it.

  As shown in FIG. 8A, when the post-fixing paper discharge unit 320 is positioned at the normal position, the protrusion 326a of the post-fixing paper discharge unit 320 presses the retracting arm 327, and the lever 327b is moved to the belt detection unit. It is separated from 500. Thereby, the belt detection pin 502a can maintain the state contact | abutted to the edge of the pressurization belt 200, as shown in FIG.

  As shown in FIG. 8B, when the post-fixing paper discharge unit 320 is positioned at the retracted position, the protrusion 326 a of the post-fixing paper discharge unit 320 releases the restraint of the retracting arm 327. As a result, the retracting arm 327 is rotated by a spring bias described later, and the lever 327 b comes into contact with the belt detection unit 500. As a result, the belt detection pin 502a is forcibly moved from the position shown in FIG. 5 to a position outside the edge of the pressure belt 200.

  That is, when the fixing paper discharge unit 320 is in the closed state, the retracting arm 327 is retracted by contacting the protrusion 326a, but when the fixing paper discharge unit 320 is in the closed state, the protrusion 326a moves away so that the retracting arm 327 can rotate. Become.

  As shown in FIG. 9A, a protrusion 326 a is provided at the lower part of the paper discharge guide 326. In addition, a retracting arm 327 that is rotatable about a shaft 327a is disposed at a lower portion of the protrusion 326a. The retraction arm 327 is urged by a considerably strong force of 5N in the direction of the arrow R7 by an arm spring (328: FIG. 10A). Since the paper discharge unit 320 after fixing is in the closed state, the retracting arm 327 rotates against the arm spring (328: FIG. 10A) to the contact position of the protrusion 326a.

  As shown in FIG. 10A, at this time, the belt position detection flag 501 of the belt position detection unit 500 is separated from the retracting arm 327. The belt position detection flag 501 is urged by the arm urging spring 503 to rotate the belt position detection arm 502 and bring the belt detection pin 502 a into contact with the edge of the pressure belt 200.

  As shown in FIG. 9B, when the post-fixing paper discharge unit 320 is in the open state, the paper discharge guide 326 rotates in the direction of the arrow R8 and changes its position, and the protrusion 326a at the tip restrains the retracting arm 327. No longer.

  For this reason, the retracting arm 327 rotates in accordance with the biasing direction of the arm spring (328: FIG. 10A), and the lever 327b forcibly rotates the belt position detection flag 501 in the arrow R9 direction. The belt position detection flag 501 is rotated around the flag rotation shaft 505 to move the belt detection pin 502 a away from the edge of the pressure belt 200.

  As shown in FIG. 10B, when the retracting arm 327 is rotated by the moment of the arm spring 328 and comes into contact with the belt position detection flag 501, the belt position detection flag 501 rotates in the direction of the arrow R9. As a result, the belt position detection arm 502 engaged with the belt position detection flag 501 rotates in the direction of the arrow R10 to separate the belt detection pin 502a from the edge of the pressure belt 200.

  Compared with the biasing force 1N of the arm biasing spring 503 that biases the belt position detection flag 501 in the direction opposite to the arrow R9, the biasing force of the arm spring 328 of the retracting arm 327 that rotates the belt position detection flag 501 in the arrow R9 direction. 5N is much larger. For this reason, the belt position detection flag 501 rotates in the direction of the arrow R9 against the arm biasing spring 503, and the belt detection pin 502a retracts outside the moving range of the pressure belt 200 by the steering control. Since the retracted position of the belt detection pin 502a is set outside the shift control range of the pressure belt 200 indicated by a broken line, the belt detection pin 502a is moved to the pressure belt when the pressure belt module 301 is removed and attached. No contact with 200. Even if the pressure belt 200 is changed at a position extremely close to the belt detection pin 502a, the belt detection pin 502a does not contact the pressure belt 200.

  As shown in FIG. 7B, the fixing belt module 300 can be attached to and detached from the frame body 302 only after such a state is reached. Even when the fixing belt module 300 is removed for replacement of the pressure belt module 301, the belt detection pin 502a is not in contact with the pressure belt 200 as shown in FIG.

  Therefore, it is possible to take out the pressure belt module 301 upward with respect to the frame body 302 without bringing the belt detection pin 502a and the pressure belt 200 into contact with each other.

  When the interlocking mechanism 420 according to the first embodiment is not provided, the belt detection pin 502a follows the urging force of the arm urging spring 503 as shown in FIG. Exists inside. For this reason, the edge of the pressure belt 200 may be damaged. However, by providing the interlocking mechanism of the first embodiment, the possibility of damaging the pressure belt 200 is reduced.

<Example 2>
In the first embodiment, in conjunction with the movement of the fixing paper discharge unit 320 that moves from the closed state to the open state, the restraint of the retracting arm 327 that is urged by the arm spring 328 to rotate is released.

  In the second embodiment, in conjunction with the movement of the fixing belt module 300 when it is removed from the frame 302, the restraint of the retracting arm 327 that is biased by the arm spring 328 to rotate is released. For this purpose, a protrusion corresponding to the protrusion 326 a of the post-fixing discharge unit 320 shown in FIG. 9A is fixed to the fixing belt module 300.

<Example 3>
11 is an explanatory view of the interlocking mechanism in the second embodiment, FIG. 12 is a side view of the interlocking mechanism, and FIG. 13 is an explanatory view of a state in which the fixing device is pulled out using a slide guide.

  In the first embodiment, the belt detection pin 502 a is separated from the edge of the pressure belt 200 in conjunction with the movement of the paper discharge unit 320 after fixing. On the other hand, in the third embodiment, the belt detection pin 502 a is separated from the edge of the pressure belt 200 in conjunction with the pulling movement of the fixing device 27 using the slide guide 103.

  As shown in FIG. 4, the fixing device 27 can be pulled out to a work position outside the housing of the image forming apparatus 100 using a slide guide 103. The state in which the fixing device 27 is pulled out is a state in which a jamming of the recording material or a serviceman maintains the fixing device 27 in the market.

  As shown in FIG. 11, in the belt position detection unit 500, as described with reference to FIG. 5, a rotatable belt position detection arm 502 is engaged with a rotatable belt position detection flag 501. Then, the belt detection pin 502a is brought into contact with the edge of the pressure belt 200, and position detection for steering control of the pressure belt 200 is performed.

  However, the entire belt position detection unit 500 is attached to the frame 302 of the fixing device 27 so as to be movable in the direction of the arrow R12 and in the opposite direction. A long hole 512 is formed in the base plate 511 of the belt position detection unit 500, and a guide pin 513 fixed to the frame body 302 of the fixing device 27 is engaged with the long hole 512. The base plate 511 is urged in the direction of the arrow R12 by the compression spring 507 with respect to the frame body 302.

  As shown in FIG. 12, the front end of the base plate 511 is brought into contact with the rear side plate 700 of the image forming apparatus 100, and the fixing device 27 is moved in the direction of the arrow R12 against the urging force of the compression spring 507. Device 27 is positioned in the normal position.

  As shown in FIG. 11, when the fixing device 27 is accommodated in the normal position in the housing of the image forming apparatus 100, the position of the fixing device 27 is determined by the shaft 601 provided on the rear side plate 700. When the base plate 511 supporting the belt position detection unit 500 is pressed against the rear plate 700, the belt detection pin 502a comes into contact with the edge of the pressure belt 200 by the biasing force of the arm biasing spring 503. Thus, the position of the pressure belt 200 is detected.

  In this state, the steering control for correcting the belt shift operates normally. At this time, the belt position detection unit 500 moves in the direction of the arrow R12 within the range of the movable stroke of the guide pin 513 along the long hole 512, and the belt detection pin 502a is brought into contact with the edge of the pressure belt 200. Yes.

  As shown in FIG. 13, when the fixing device 27 is pulled out using the slide guide 103, the base plate 511 biased by the compression spring 507 moves in the direction of the arrow R <b> 12, and the belt detection pin 502 a is attached to the pressure belt 200. Separate from the edge. The belt position detection unit 500 moves with respect to the frame body 302 by the first 10 mm pull-out of the fixing device 27, and the belt position detection is performed at a position on the frame body 302 where the belt detection pin 502 a does not contact the pressure belt 200. The entire unit 500 is positioned.

  When the fixing device 27 is pulled out, the rear side plate 700 of the image forming apparatus 100 is relatively retracted. Then, the base plate 511 that has been in contact with the rear side plate 700 moves in the direction of the arrow R12 in accordance with the biasing force of the compression spring 507. By this operation, the belt detection pin 502 a fixed to the belt position detection arm 502 is retracted from the edge of the pressure belt 200.

  In the third exemplary embodiment, when the fixing device 27 is accessible, the belt detection pin 502a is retracted from the pressure belt 200, so that the possibility of damaging the pressure belt 200 when replacing the pressure belt module 301 is low. Become.

  Although the details of the present invention have been described above by the three embodiments, the present invention is not applied only to the above-described embodiments. For example, steering control for detecting the position of the fixing belt 220 of the fixing belt module 300 by contacting a belt detection pin is also performed. For this reason, it is desirable to retract the belt detection pin to a position where it does not come into contact with the fixing belt 300 in conjunction with the retracting of the paper discharge unit 320 after fixing.

It is explanatory drawing of a structure of the image forming apparatus of 1st Embodiment. FIG. 3 is an explanatory diagram of a configuration of a fixing device. It is a perspective view of the assembly structure of the fixing device. FIG. 10 is an explanatory diagram of a drawer structure of the fixing device. It is explanatory drawing of a structure of the belt detection unit which detects a pressurization belt. It is explanatory drawing of the steering operation of a pressure belt. FIG. 4 is a front view of the fixing device showing a normal position and a retracted position of the paper discharge unit after fixing. FIG. 3 is a front view of the fixing device with the fixing belt module and the pressure belt module removed from the frame. It is explanatory drawing of operation | movement of an interlocking mechanism. It is explanatory drawing of operation | movement of the belt detection unit accompanying operation | movement of an interlock mechanism. It is explanatory drawing of the interlocking mechanism in Example 2. FIG. It is a side view of an interlocking mechanism. FIG. 6 is an explanatory diagram of a state in which the fixing device is pulled out using a slide guide.

Explanation of symbols

20Y, 20M, 20C, 20K photoconductor (photosensitive drum)
25 Intermediate transfer body (intermediate transfer belt)
27 Image heating device (fixing device)
100 image forming apparatus 101 temperature control unit 102 steering control unit 103 slide guide 200 pressure belt 201 pressure roller 202 pressure tension roller 204 pressure pad 220 fixing belt 221 fixing roller 222 fixing tension roller 223 fixing pad 224 induction heating coil 300 Fixing belt module 301 Pressure belt module 302 Frame 320 Paper discharge unit after fixing 322 Separating sheet metal 323 Paper discharge upper roller 324 Paper discharge lower roller 326 Paper discharge guide 500 Belt position detection unit 501 Support member (belt position detection flag)
502 belt position detection arm 502a detection member (belt detection pin)
503 Arm biasing springs 503a and 503b Photo sensor 505 Flag rotating shaft 506 Arm rotating shaft 600 Stepping motor 700 Rear side plate

Claims (3)

A belt unit assembled so that belt members supported by a plurality of support rotating bodies can be integrally replaced together with the plurality of support rotating bodies;
A base member configured to be removably attached to the belt unit;
A detection member that detects an edge of the belt member to perform steering control of the belt member ;
A support member capable of a predetermined movement with respect to the base member so that the detection member contacts and separates from an edge of the belt member;
A spring member for biasing the support member so that the detection member abuts against an edge of the belt member;
The belt unit can not be removed from the base member in a state where the belt unit is located at the normal position, and the belt unit can be removed from the base member by moving away from the normal position prior to removal of the belt unit. Mechanical parts that can be
Abutting against the support member as the mechanism part is moved away from the normal position, the detection member is forcibly separated from the edge against the spring bias, and the detection member is normally detected. The sensor member is moved from the position to the outside position of the edge of the belt member, and the contact with the support member is released along with the operation of positioning the mechanical component to the normal position, and the detection member is returned to the normal detection position. image heating device comprising a contact member which, further comprising a. The mechanism part, the image heating apparatus according to claim 1, wherein the rotating unit der Rukoto including a rotating body forming the heating nip of the recording material was pressed against the belt member. The mechanism parts claims, characterized in that a discharge rotary body unit including a discharge rotary bodies for conveying the pre-type recording medium discharged from the heating nip of the recording material to be formed by pressing the rotating member to the belt member Item 2. The image heating apparatus according to Item 1 .

Images