JP2012058559A - Fixing device and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fixing device that offers an excellent image without image stains even after a recording material is jammed at a fixing part.SOLUTION: An post-fixing discharge unit 320 is movably provided between a proximity position where a separation sheet metal 321 is in the proximity of a fixing belt 220, and a retracted position where the separation sheet metal 321 retracts from the fixing belt 220. A felt member 403 that is a cleaning member cleans the rear face 321b side of the tip of the separation sheet metal 321 in accordance with the moving operation of the post-fixing discharge unit 320 between the proximity position and the retracted position.

Description

  The present invention relates to a fixing device that can be applied to an image forming apparatus such as a copying machine, a printer, a facsimile machine, or a complex machine that combines them.

  In an electrophotographic image forming apparatus, a process of fixing a toner image to a recording material such as a recording sheet through each process of charging, exposure, development, transfer, and fixing is common. In a fixing process in an image forming apparatus, a fixing method of a roller pair using a fixing roller and a pressure roller has been conventionally used. From the viewpoint of improving productivity and image quality, belt-type fixing devices in which either or both of the roller pairs are replaced with belts wound around a plurality of rollers have become mainstream.

  In the fixing step, a fixing rotator is pressed against a fixing rotator whose surface is covered with an elastic layer, and the elastic layer of the fixing rotator is elastically deformed to form a fixing nip portion. The toner image transferred to the recording material passes through the fixing nip portion, so that the recording material is pressurized and melted and fixed to the recording material.

  When the toner is melted at the fixing nip portion, the viscosity of the toner increases. Therefore, the bonding force between the fixing rotator and the toner increases, and the recording material is easily wound around the fixing rotator. In order to prevent the recording material from being wound around the fixing rotator, a separating member such as a separation plate or a separation claw is provided in the vicinity of the fixing rotator as a recording material separating means. These separation means can be broadly classified into contact type and non-contact type. However, in order to realize high image quality of the image forming apparatus, a non-contact type rather than a contact type that easily damages the surface layer of the fixing rotating body. Is preferred. In the case of the non-contact type, in order to improve the sheet separating performance, it is necessary to bring the separating means close to the fixing rotating body with a minute gap.

  In the unlikely event that the recording material is clogged in the fixing unit, there are a so-called accordion jam that causes the recording material to be clogged after passing through the fixing nip portion, and a wrapping jam in which the recording material is wound around the fixing rotating body. . Patent document 1 is mentioned as a method of improving the jam processing property at the time of these jam processing. In Patent Document 1, when a wrapping jam is processed, the jam guide space is secured by rotating the main guide in a state where the separation claw is covered by the protective member.

JP 2005-077684 A

  However, the technique of Patent Document 1 has the following problems. That is, the periphery of the fixing nip is a high temperature atmosphere, and the wax (WAX) component contained in the toner is volatilized from the toner heated in the fixing nip, and is vaporized in the atmosphere. Since the separating means is close to the fixing rotator with a minute gap, the wax vaporized by heating the toner at the fixing nip easily adheres to the tip of the separation claw. Further, when the recording material is separated from the fixing rotator, the toner surface of the recording material is separated so as to be peeled off from the fixing rotator, so that the toner adheres to the tip of the separating means and is easily solidified. As described above, when the separation unit is moved from the vicinity of the fixing rotating body to secure an operation space for the jam processing, after the jam processing is performed in a state where the foreign matter adheres to the tip of the separation unit, the separation unit is set to a predetermined position. There is a possibility that foreign matters may be scattered on the surface of the fixing rotating body due to the reaction when returning to the position. As a result, there is a possibility that the quality of the recording material after the jam processing is deteriorated.

  A typical configuration of the fixing device according to the present invention for achieving the above object includes a fixing rotator provided with a heating means, and a pressing rotator arranged in pressure contact with the fixing rotator. A fixing device for fixing an image by heating and pressurizing an unfixed image on a recording material by the fixing rotator and the pressing rotator, the fixing rotator being adjacent to the fixing rotator. A post-fixing discharge unit comprising: a separating unit capable of separating the recording material from the body; and a recording material guiding member for guiding the recording material separated from the fixing rotating body by the separating unit to the downstream side; and The post-fixing discharge unit is movable between a proximity position where the separation means is close to the fixing rotator and a retreat position where the separation means is retracted from the fixing rotator. After the fixing Is accompanied with the movement operation between output and the near position of the unit and the retracted position, wherein said cleaning means is arranged the cleaning means to clean the separating means.

  According to the present invention, the cleaning unit can clean the wax and toner adhering to the separating unit adjacent to the fixing rotating body in accordance with the movement operation between the proximity position and the retracted position of the post-fixing discharge unit. Therefore, it is possible to prevent image defects of the recording material and obtain a high-quality output product.

1 is an explanatory cross-sectional view illustrating a configuration of an image forming apparatus including a fixing device according to the present invention. FIG. 3 is an explanatory cross-sectional view illustrating a configuration of a fixing device. FIG. 4 is an explanatory cross-sectional view showing a closed state in which the post-fix discharge unit forms a recording material conveyance path in the fixing device. FIG. 6 is an explanatory cross-sectional view showing an open state in which a post-fixing discharge unit is rotated and retracted in the fixing device to handle a recording material jam. FIG. 4 is an explanatory cross-sectional view showing a closed state in which the post-fix discharge unit forms a recording material conveyance path in the fixing device. It is an isometric view explanatory drawing which shows the structure of a cleaning means. FIG. 3 is a cross-sectional explanatory view illustrating a configuration of a fixing device according to the present invention. In the fixing device according to the present invention, it is a cross-sectional explanatory view showing a state in which the separating means is cleaned by the cleaning means in accordance with the movement operation between the proximity position and the retracted position of the post-fixing discharge unit. In the fixing device according to the present invention, after the discharge unit after fixing is rotated and retracted to handle the jam of the recording material, the discharge unit after fixing is rotated and returned to the closed state in which the recording material conveyance path is formed. FIG.

  An embodiment of an image forming apparatus provided with a fixing measure according to the present invention will be specifically described with reference to the drawings. FIG. 1 shows a configuration of an apparatus main body 100 of an image forming apparatus provided in a copying machine, a printer, a facsimile machine, or a complex machine combining these, and an unfixed toner image transferred onto a sheet S as a recording material. There is a fixing device that applies heat and pressure to the permanent fixing process. However, although a full color intermediate transfer system is shown as a specific example of the image forming apparatus, it is not particularly limited thereto.

  The apparatus main body 100 includes, for example, image carriers 20Y, 20M, which carry electrostatic latent images on the surface corresponding to four-color toner images of Y (yellow), M (magenta), C (cyan), and K (black). It has 20C and 20K. The image carriers 20Y to 20K are configured as image forming means for forming a toner image on the sheet S. Hereinafter, in order to avoid complication of the description, the four image carriers 20Y, 20M, 20C, and 20K will be described as being representative of the image carrier 20, and the following charging means, exposure means, and developing device will be similarly described. Describe with a representative code.

  The surfaces of the four image carriers 20 are uniformly charged to a required potential by primary charging means 21Y, 21M, 21C, and 21K. Thereafter, the surface of each image carrier 20 is exposed by exposure means 22Y, 22M, 22C, and 22K, whereby an electrostatic latent image is formed on these image carriers 20. The electrostatic latent image on the image carrier 20 is developed with a developer by the developing devices 23Y, 23M, 23C, and 23K, and is visualized as a toner image.

  As shown in FIG. 1, in the apparatus main body 100, the image forming units 200Y, 200M, 200C, and 200K corresponding to the four color toner image formations are arranged in series, and the processes until the visible image is formed are arranged in parallel for each color. A tandem system for processing is adopted.

  The toner image on the image carrier 20 developed by the developing device 23 is sequentially superposed on the intermediate transfer member 25 by, for example, an endless belt by the primary transfer devices 24Y, 24M, 24C, and 24K to be primary transferred. Then, the toner image on the intermediate transfer member 25 that has been primary-transferred for all colors is collectively transferred onto the sheet S by the secondary transfer device 26. The sheet S is conveyed to the secondary transfer device 26 by the sheet feeding unit. After the secondary transfer, the sheet S carrying the unfixed toner image is conveyed to the belt-type fixing device 27 according to the present embodiment, and is heated and pressed by the fixing device 27. As a result, the unfixed toner image formed by the image forming means is melted and softened and fixed on the sheet S, and is discharged onto the discharge tray 28 when the fixing is completed. When forming an image on the back side of the sheet S, the sheet S is reversed by the sheet reversing path 29 and then conveyed again to the secondary transfer device 26 via the double-sided conveying path 30 to be back side of the sheet S. An image is formed on.

  As described above, a series of image forming processes from charging, exposure, development, transfer, and fixing are executed, and a toner image is recorded and formed on the sheet S. In the monochrome image forming apparatus, only the black image forming unit 200K exists. The order and configuration of the Y, M, C, and K image forming units 200 are not limited to this.

  Next, the configuration of the fixing device 27 will be described with reference to FIGS. FIG. 2 shows a configuration around the fixing nip portion N of the fixing device 27. The fixing device 27 includes a fixing belt 220 serving as a fixing rotator including an induction heating coil 224 serving as a heating unit, and a pressure belt 230 serving as a pressing rotator disposed in pressure contact with the fixing belt 220. Have Each of the fixing belt 220 and the pressure belt 230 has a configuration in which the belt is wound around two rollers, and the inside of each of the fixing belt 220 and the pressure belt 230 is configured by the following members. ing.

  The fixing belt 220 which is a main part of the heating body is formed in an endless shape, and the fixing belt 220 is looped around the fixing roller 221 and the fixing tension roller 222. The fixing belt 220 can be appropriately selected as long as it generates heat by the induction heating coil 224 and has heat resistance. For example, a silicon metal having a thickness of 500 μm is coated on 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. And what coat | covered the PFA (tetrafluoroethylene perfluoroalkyl vinyl ether copolymer) tube on the surface layer can be used. 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. This current is changed to Joule heat by the resistance of the metal layer to cause the metal layer to generate heat, and the fixing belt 220 is heated.

  Inside the fixing belt 220, a temperature detecting means such as a thermistor (not shown) is disposed, and the temperature of the inner surface of the fixing belt 220 is detected based on an output signal of the thermistor. Heating control is set so that the temperature of the inner surface of the fixing belt 220 is, for example, 180 ° C.

  The fixing roller 221 is formed by integrally forming a heat-resistant silicon rubber elastic layer on a core metal surface layer in which an outer diameter of a solid material made of stainless steel (SUS) is formed with a diameter of 19 mm. The fixing roller 221 is disposed on the exit side (left side in FIG. 2) of the fixing nip N between the fixing belt 220 and the pressure belt 230, and the elastic layer of the surface rubber is elasticized by the pressure contact with the pressure roller 231. It can be deformed and distorted. The fixing tension roller 222 applies a tension set to 120 N, for example, in order to maintain the belt tension optimally at all times. The fixing tension roller 222 is a hollow roller made of, for example, a stainless material and having an outer diameter of 20 mm and an inner diameter of 16 mm.

  A fixing pad stay 223 is provided inside the fixing belt 220 on the inlet side (right side in FIG. 2) of the fixing nip N between the pressure belt 230 and the fixing belt 220, that is, on the upstream side of the fixing roller 221. . The fixing pad stay 223 is made of, for example, a stainless material. The fixing pad stay 223 is pressed against a pressure pad 233 provided inside the pressure belt 230 with a set pressure of 400 N, for example, and a fixing nip portion N is formed between the pressure belt 230 and the fixing roller 221. Forming.

  The pressure belt 230, which is the main part of the pressure body, is formed in an endless shape. The pressure belt 230 is looped around the pressure roller 231 and the pressure tension roller 232. . The pressure roller 231 is, for example, a hollow rod made of stainless steel (SUS), and is formed with an outer diameter of 21 mm and an inner diameter of about 19 mm. The pressure roller 231 has an exit side of the fixing nip portion N between the pressure belt 230 and the fixing belt 220 ( It is arranged on the left side of FIG. The pressure tension roller 232 is a hollow roller formed of, for example, a stainless material with an outer diameter of about 22 mm and an inner diameter of about 20 mm, and functions as a roller that applies an appropriate tension to the pressure belt 230. Further, a heater 234 as a heating element is mounted inside the pressure roller 231 so as to heat the pressure belt 230. For example, a halogen heater is used as the heater 234, but other heaters can be used as long as they can be used as a heat source.

  Outside the image area on the outer peripheral surface of the pressure belt 230, a temperature detecting means such as a thermistor (not shown) is in contact. Then, based on the output signal of the thermistor, the temperature of the outer peripheral surface of the pressure belt 230 is detected. For example, the heating control is set so that the surface temperature of the pressure belt 230 becomes 100 ° C.

  The pressure pad 233 corresponds to the inlet side (right side in FIG. 2) of the fixing nip N formed between the pressure belt 230 and the fixing belt 220, that is, the upstream side of the pressure roller 231. It is provided inside the belt 230 and is made of, for example, silicon rubber. The pressure pad 233 is pressed against the pressure belt 230 with a set pressure of 400 N, for example, and a fixing nip portion N is formed between the pressure belt 230 and the fixing belt 220. The sheet S to which the unfixed toner image (unfixed image) is transferred passes through the fixing nip portion N, so that the unfixed toner image (unfixed image) is heated and pressed to be on the sheet S (on the recording material). The toner image is fixed to the toner image.

  Next, with reference to FIG. 3, the conveying operation of the sheet S at the time of copying or printing in the fixing device 27 will be described. When a copy or print job is started, the sheet S fed by the sheet feeding device is electrostatically transferred with unfixed toner in the transfer process and conveyed toward the fixing nip N. An inlet guide 310 is provided in the fixing device 27 so that the sheet S can be easily introduced into the fixing nip portion N.

  On the other hand, the sheet S is conveyed along the guide surface of the entrance guide 310 and enters the fixing nip portion N. In the fixing nip portion N, the unfixed toner is sufficiently melted by heat and pressure and enters between the fibers of the sheet S made of paper, whereby the sheet S and the toner image are fixed. The sheet S receives a conveying force due to the rotation of the fixing belt 220 and the pressure belt 230, and is conveyed into the post-fixing discharge unit 320 in FIG.

  The post-fixing discharge unit 320 is provided with a separation sheet metal 321 as separation means that can separate the sheet S from the fixing belt 220 in the vicinity of the fixing belt 220, and the separation sheet metal 321 is minute relative to the fixing belt 220. It arrange | positions so that it may adjoin with a space | gap. Separation sheet metal 321 is a sheet metal made of stainless steel having a thickness of about 1.0 mm, and a sheet metal made of a similar stainless material and having a thickness of about 0.2 mm integrated by welding or the like. As the separation means, in addition to the non-contact type sheet metal as in the present embodiment, a non-contact type separation claw type and a contact type separation means can be used. The separation sheet metal 321 itself serves as a sheet guide serving as a recording material guiding member for guiding the sheet S separated from the fixing belt 220 by the separation sheet metal 321 to the downstream side (left side in FIG. 3). A discharge guide 322 that is also a recording material guide member is disposed below the separation sheet metal 321.

  On the downstream side in the sheet conveying direction of the discharge guide 322 (left side in FIG. 3), a discharge roller pair including a discharge upper roller 323 and a discharge lower roller 324, which are also recording material guide members, is provided. Then, the sheet S separated from the fixing belt 220 by the separation sheet metal 321 is conveyed in the sheet discharge direction. The discharge upper roller 323 is a bar made of solid aluminum and has a diameter of about 15 mm. Further, the discharge lower roller 324 is formed by molding a heat-resistant rubber member such as silicon on a surface of a stainless bar having a diameter of about 8 mm so as to give a conveying force to the sheet S.

  The sheet S is nipped and conveyed by the pressure belt 230 and the fixing belt 220, separated from the fixing belt 220 by the separation sheet metal 321, and conveyed to the post-fixing discharge unit 320. Then, it passes through a space formed between the lower part of the separation sheet metal 321 and the upper part of the discharge guide 322, and is sandwiched between the discharge roller pair composed of the discharge upper roller 323 and the discharge lower roller 324 and discharged downstream. The In the discharge guide 322, a discharge sensor flag 325 is provided at a substantially central portion in the longitudinal direction, and a discharge sensor 326 is provided below the discharge sensor flag 325. When the leading edge of the sheet S collides with the discharge sensor flag 325, the discharge sensor flag 325 rotates, and the detection unit 325a of the discharge sensor flag 325 changes the discharge sensor 326 from the light-transmitting state to the light-blocking state. The arrival of is detected.

  Next, an operation when the sheet S is jammed in the post-fixing discharge unit 320 will be described with reference to FIGS. In the fixing nip portion N, the unfixed toner transferred to the sheet S is sufficiently melted, so that it is necessary to apply a large amount of heat. However, since the viscosity of the toner increases when the toner is in a molten state, the toner acts like an adhesive between the fixing belt 220 and the sheet S. For this reason, even after the leading edge of the sheet S passes through the fixing nip N, there is a phenomenon that the sheet S is not separated by the separation sheet metal 321 but is wound around the fixing belt 220. When this phenomenon occurs, the discharge sensor 326 of the post-fixing discharge unit 320 cannot detect the arrival of the sheet S, and therefore a control unit (not shown) determines that the sheet S is jammed. Hereinafter, this state is referred to as wrapping jam. This wrapping jam causes the sheet S to uniformly wrap around the surface of the fixing belt 220, and the jam handling performance is very poor. Further, since the surface of the fixing belt 220 is at a high temperature, the user needs to handle the jam. It is necessary to secure a large space for inserting.

  In the present embodiment, as shown in FIG. 4, the post-fixing discharge unit 320 is provided so as to be rotatable about a rotation shaft 327 provided in an apparatus frame (not shown) for jam processing. In the post-fixing discharge unit 320, one end 350a of a spring 350 is hooked on the discharge frame 340, and the other end 350b of the spring 350 is hooked on a shaft 351 protruding from a device frame (not shown). Accordingly, the post-fixing discharge unit 320 is urged by the pulling force of the spring 350 so as to maintain the closed state in which the sheet conveyance path is formed as shown in FIGS. That is, since the spring 350 is a tension spring, the post-fixing discharge unit 320 is urged around the rotation shaft 327 by the force in the direction of arrow A in FIG. As shown in FIGS. 3 and 5, the closed state in which the sheet conveying path is formed is maintained.

  As shown in FIG. 4, when the sheet S is jammed, the post-fixing discharge unit 320 is rotated in the direction of arrow B in FIG. 4 around the rotation shaft 327, and the separation sheet metal 321 is retracted from the fixing belt 220. The jam processing space is secured. At this time, since the spring 350 is on the left side of the rotating shaft 327 in FIG. 4, the discharge frame 340 pulled by the spring 350 is urged around the rotating shaft 327 by the force in the direction of arrow B in FIG. As shown in FIG. 4, the open state can be maintained. As described above, a toggle method is used in which two operation positions, ie, a proximity position where the separation sheet metal 321 is close to the fixing belt 220 and a retraction position where the separation sheet metal 321 is retracted from the fixing belt 220 are movable by a seesaw method. Accordingly, when the user jams the sheet S, the toggle state of the post-fixing discharge unit 320 according to the present embodiment is maintained even when the post-fixing discharge unit 320 is not held by hand. The moving operation by the method contributes to the improvement of the jam handling performance.

  When returning the post-fixing discharge unit 320 to the closed state where the sheet conveying path is formed as shown in FIGS. 3 and 5, the post-fixing discharge unit 320 is moved in the direction of arrow A in FIG. Rotate. Then, a positioning pin 328 serving as positioning means provided in the apparatus frame (not shown) engages with an engagement groove 340a of the discharge frame 340 provided with the separation sheet metal 321, and the post-fixing discharge unit 320 is rotated in the rotational direction. The position is determined. That is, the positioning pins 328 provided on the apparatus frame (not shown) are configured as positioning means for positioning the post-fixing discharge unit 320 at a close position where the separation sheet metal 321 is close to the fixing belt 220.

  In order to improve the jam handling performance, the post-fixing discharge unit 320 may not be configured to rotate about the rotation shaft 327 as in the present embodiment. For example, the post-fixing discharge unit 320 is guided by a guide portion (not shown), and moves between a proximity position where the separation sheet metal 321 is close to the fixing belt 220 and a retreat position where the separation sheet metal 321 is retracted from the fixing belt 220 by a sliding method. It can also be configured.

  By the way, the fixing device 27, in particular, the fixing belt 220 and the pressure belt 230 are maintained at a high temperature in order to melt the toner. In the fixing nip portion N, a large amount of heat is applied to the toner in order to bring the toner into a molten state. The toner contains components such as wax for imparting a releasing action and a gloss action, and these components have a lower melting point than that of the toner. Inside the fixing nip N, those components contained in the toner are vaporized, and the sheet S is discharged to the discharge side (left side in FIG. 3) of the fixing nip N and at the same time, the vaporized components such as wax are removed. Freed from part N. For this reason, in particular, members disposed on the discharge side (left side in FIG. 3) and the upper portion of the fixing nip portion N are exposed to the atmosphere in which the wax is vaporized, and the wax adheres to the surfaces of these members. In the case of the separation sheet metal 321, the sheet S passes through the guide surface 321 a on the lower side of the separation sheet metal 321 in FIG. It reattaches to the sheet S and does not accumulate. However, since the sheet S does not pass through the upper surface in FIG. 3 opposite to the guide surface 321a of the separation sheet metal 321 (hereinafter referred to as “rear surface 321b”), the wax vaporized inside the fixing nip N is separated. It gradually accumulates on the back surface 321b of the sheet metal 321.

  With the wax deposited on the back surface 321b of the separation sheet metal 321, the post-fixing discharge unit 320 is vigorously returned from the open state shown in FIG. 4 to the closed state where the sheet conveyance path is formed as shown in FIGS. Then, the wax accumulated on the back surface 321b of the separation sheet metal 321 may be scattered toward the fixing belt 220 and adhere to the surface of the fixing belt 220. In that case, in the conventional apparatus, measures such as wiping off the wax by the maintenance of a service person in the market are necessary.

  In the present embodiment, a cleaning unit having a felt member 403 serving as a cleaning member is provided on a positioning pin 328 as a positioning unit that positions the post-fixing discharge unit 320 at a close position where the separation sheet metal 321 is close to the fixing belt 220. . An example of a cleaning means having a felt member 403 that serves as a cleaning member for cleaning the separation sheet metal 321 is shown in FIG. The cleaning means of this embodiment is provided with a locking portion 328a having a D-shaped cross section at the end of a positioning pin 328 provided on a device frame (not shown). Then, the locking portion 328a is inserted into a D-shaped locking hole 400a provided in the sheet metal 400, and the sheet metal 400 engages with the positioning pin 328 in a non-rotatable manner. A metal shaft 401 that is non-rotatably engaged is fixed to the sheet metal 400, and a pipe member 402 as a cylindrical member made of metal, resin, or the like is provided outside the shaft 401. Around the pipe member 402, a felt member 403 serving as a cleaning member covering the periphery of the pipe member 402 is wound. A fitting portion between the metal shaft 401 and the pipe member 402 is provided with a one-way clutch 404 serving as a rotation control means. When the felt member 403 receives a rotational force in the direction of arrow D in FIG. The one-way clutch 404 of the member 402 is engaged with the shaft 401. Since the shaft 401 is fixed to the sheet metal 400 so as not to rotate, the pipe member 402 and the felt member 403 do not rotate in the direction of arrow D in FIG. Conversely, when the felt member 403 receives a rotational force in the direction of arrow E in FIG. 6, the pipe member 402 idles with respect to the shaft 401 by the action of the one-way clutch 404, so that the pipe member 402 and the felt member 403 Can rotate in E direction.

  A trajectory 500 at the tip of the separation sheet metal 321 when the post-fixing discharge unit 320 is rotated about the rotation shaft 327 is indicated by a broken line shown in FIG. Since the separation sheet metal 321 is located on the upper right side in FIG. 7 relative to the rotation shaft 327 inside the post-fixing discharge unit 320, the post-fixing discharge unit 320 is counterclockwise in FIG. When rotated in the turning direction, the tip of the separation sheet metal 321 moves in the upper left direction in FIG.

  A felt member 403 serving as a cleaning member is disposed on a locus 500 at the tip of the separation sheet metal 321, and the post-fixing discharge unit 320 is rotated around a rotation shaft 327. At this time, as shown in FIG. 8, the felt member 403 of the cleaning member and the back surface 321 b side of the front end of the separation sheet metal 321 come into contact with each other. The felt member 403, which is a cleaning member, has a shaft 401 that rotatably supports the felt member 403 fixed to the sheet metal 400 so that the sheet metal 400 cannot rotate to a positioning pin 328 fixed to an apparatus frame (not shown). Is engaged. Thus, even when the post-fixing discharge unit 320 rotates about the rotation shaft 327, the position of the felt member 403 that serves as a cleaning member (the position of the shaft 401) does not move. Here, as shown in FIG. 8, when the post-fixing discharge unit 320 is in the open state shown in FIG. 4, the back surface 321b side of the tip of the separation sheet metal 321 and the felt member 403 as a cleaning member abut, A force in the direction of arrow D in FIG. However, even if the force in the direction of arrow D in FIG. 8 acts on the felt member 403, the one-way clutch 404 is in the meshing direction. For this reason, the felt member 403 which is a cleaning member does not rotate in the direction of arrow D in FIG. Then, with the rotational movement in the direction of arrow B in FIG. 8 about the rotational shaft 327 of the post-fixing discharge unit 320, the back surface 321b side of the front end of the separation sheet metal 321 rubs against the stationary felt member 403. Move while. At this time, foreign matters such as wax and toner adhering to the back surface 321b side of the front end of the separation sheet metal 321 are scraped off by the felt member 403, and the back surface 321b side of the front end of the separation sheet metal 321 is cleaned.

  Thus, as shown in FIG. 8, when the post-fixing discharge unit 320 is in the open state shown in FIG. 4, the back surface 321b at the tip of the separation sheet metal 321 contacts the felt member 403 serving as a cleaning member. As a result, foreign substances such as wax and toner adhering to the back surface 321b side of the front end of the separation sheet metal 321 are cleaned. And the part which the back surface 321b side of the front-end | tip of the separation sheet metal 321 of the felt member 403 contacted, and foreign materials, such as a wax and a toner, adhere and become dirty. Then, when the post-fixing discharge unit 320 is rotated about the rotation shaft 327 in the direction of arrow A in FIG. 9 to form a closed state in which a sheet conveyance path is formed as shown in FIGS. As shown in FIG. 9, the front end of the separation sheet metal 321 contacts the felt member 403 serving as a cleaning member. At this time, the felt member 403 receives a force in the direction of arrow E in FIG. 9, but the rotation in the direction of arrow E is that the one-way clutch 404 is in the idling direction, so Rotate. Then, since the part contaminated by foreign matters such as wax and toner is sent in the direction of arrow E in FIG. 9, the unused surface of the felt member 403 moves downward in FIG. In this way, the next time the post-fixing discharge unit 320 is opened as shown in FIG. 4, the unused surface of the felt member 403 comes into contact with the back surface 321b side of the front end of the separation sheet metal 321 as shown in FIG. . The post-fixing discharge unit 320 is vigorously rotated about the rotation shaft 327 in the direction of arrow A in FIG. Even if the post-fixing discharge unit 320 is returned to the closed state in which the sheet conveying path is formed as shown in FIGS. 3 and 5, no foreign matter such as toner or wax adheres to the leading end of the separation sheet metal 321. Therefore, the fixing belt 220 is not soiled, image defects recorded on the sheet S can be prevented, and a high-quality output product can be obtained.

  That is, in the present embodiment, a movement operation is performed between a proximity position where the separation sheet metal 321 of the post-fixing discharge unit 320 is close to the fixing belt 220 and a retreat position where the separation sheet metal 321 is retracted from the fixing belt 220. Along with this moving operation, the felt member 403 is disposed so as to clean the back surface 321b side of the front end of the separation sheet metal 321 by the felt member 403 serving as a cleaning member. The felt member 403 serving as a cleaning member is engaged with a positioning pin 328 serving as a positioning unit for positioning the post-fixing discharge unit 320 at a close position where the separation sheet metal 321 is close to the fixing belt 220. The one-way clutch 404 serving as a rotation control means is interlocked with any one of the moving operations in which the separation sheet metal 321 approaches and retracts from the fixing belt 220. The felt member 403 serving as the cleaning member is rotated together with the pipe member 402 serving as the cylindrical member, and the pipe member 402 and the felt member 403 are not rotated in the other operation.

220… Fixing belt (rotating body for fixing)
320 ... Post-fixing discharge unit
321 ... Separation sheet metal (separation means; recording material guide member)
321b ... back side
403 ... Felt member (cleaning member; cleaning means)

Claims (5)

A fixing rotator provided with a heating unit; and a pressing rotator disposed in pressure contact with the fixing rotator. The fixing rotator and the pressing rotator are indeterminate on the recording material. In a fixing device that fixes an image by heating and pressurizing a received image,
Separating means capable of separating the recording material from the fixing rotator close to the fixing rotator, and a recording material guide member for guiding the recording material separated from the fixing rotator by the separating means to the downstream side. A post-fixing discharge unit having:
Cleaning means for cleaning the separating means;
Have
The post-fixing discharge unit is provided movably between a proximity position where the separating means is close to the fixing rotator and a retreat position where the separating means is retracted from the fixing rotator,
A fixing device, wherein the cleaning unit is arranged so that the cleaning unit cleans the separation unit in accordance with the movement operation of the post-fixing discharge unit between the proximity position and the retracted position. The fixing device according to claim 1, wherein the cleaning unit is engaged with a positioning unit that positions the post-fixing discharge unit at a close position where the separating unit is close to the fixing rotating body. The fixing device according to claim 1, wherein the cleaning unit includes a cylindrical member and a cleaning member that covers the periphery of the cylindrical member. The separating means rotates the cleaning member together with the cylindrical member in conjunction with any one of the moving operations of approaching and retracting the fixing rotating body, and in the other operation, The fixing device according to claim 3, further comprising a rotation control unit that does not rotate the cleaning member. Image forming means for forming a toner image on a recording material;
The fixing device according to claim 1, wherein the toner image formed by the image forming unit is fixed to the recording material.
An image forming apparatus comprising:

Images