JP5300450B2 - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a small-sized apparatus which will not stain hand, clothes or the interior of the apparatus with toner of unfixed image on a sheet, or the like, when an image forming apparatus is stopped due to jamming, or the like, and the sheet stagnated and remaining on a conveyance path in the image forming apparatus is removed. <P>SOLUTION: A winding housing part 301 for winding and housing the sheet on the conveyance path is disposed in the image forming apparatus. The sheet stagnated in the apparatus due to jamming, or the like, is conveyed to the winding housing part 301 by a belt-conveying unit 112 and is wound and housed thereby. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention provides an electrophotographic image forming apparatus for forming an image on a sheet.

  In an electrophotographic image forming apparatus that forms an image on a sheet, a toner image carried on an image carrier is transferred onto the sheet in a transfer unit, and the sheet onto which the toner image has been transferred is conveyed to a fixing device by a suction conveyance belt. In general, the toner image is fixed on a sheet by a fixing device.

  In the image forming apparatus, when a jam (sheet clogging) occurs somewhere in the apparatus and the apparatus stops, a plurality of sheets other than the jammed sheet stay in the apparatus. For this reason, in order to resume image formation, it is necessary to take out all staying sheets.

  Here, an unfixed toner image is placed on the sheet on the suction conveyance belt between the transfer unit and the fixing device. Therefore, when the sheet is taken out, there is a possibility that unfixed toner on the sheet may contaminate the hand or the inside of the apparatus.

As a countermeasure for this, a mechanism has been proposed in which the suction conveyance belt is rotated and the staying paper is discharged onto a dedicated tray without passing through the fixing device (see Patent Document 1).
JP 2004-309714 A

  In the method of rotating the suction conveyance belt and discharging the staying sheet in the apparatus onto the dedicated tray without passing through the fixing device, it is necessary to provide a discharging path for the staying sheet and a dedicated tray. Therefore, a large space is required for a dedicated tray that requires a space for the sheet to be placed, so that the apparatus becomes large. Note that if the user accidentally touches the unfixed toner image on the sheet when disposing of the sheet from the dedicated tray, the hand is soiled.

  Accordingly, an object of the present invention is to provide an image forming apparatus capable of taking out a sheet staying between a transfer unit and a fixing device in a smaller space than in the past when the device is stopped due to a jam or the like. .

The image forming apparatus of the present invention includes a transfer unit that transfers a toner image to a sheet, a fixing unit that fixes the toner image transferred by the transfer unit to the sheet, and a rotational drive for winding the conveyed sheet around the outer periphery. A winding core, a pressing unit that presses the sheet to be wound against the outer periphery of the winding core, a winding storage unit that winds and stores the sheet, and a front end of the sheet before reaching the fixing unit the sheet stopped, and a transfer means for transferring to said take-up storage unit.

  According to the present invention, since the sheet on which the unfixed toner image staying between the transfer portion and the fixing unit is attached is wound and stored by the winding storage unit, it can be arranged in a small space.

  FIG. 1 is a schematic sectional view of an image forming apparatus according to an embodiment of the present invention.

(Schematic configuration of image forming apparatus)
The image forming apparatus 100 includes sheet feeding units 101 and 102 that feed stored sheets, and conveyance units 103, 104, and 105 that convey sheets fed from the sheet feeding units 101 and 102.

  The image forming apparatus 100 also includes an image forming unit 401 that forms an image on a sheet, and a fixing device 402 as a fixing unit that fixes a toner image formed on the sheet by the image forming unit on the sheet. The image forming apparatus 100 includes a rear conveyance unit 403 that conveys a sheet on which an image is fixed by the fixing device 402.

  The image forming unit 401 is provided with laser scanners 107a, 107b, 107c, and 107d that emit laser light including image information separated into colors. Photoconductors 108a, 108b, 108c, and 108d on which electrostatic latent images are formed on the surface by laser light from the laser scanners 107a, 107b, 107c, and 107d are provided. Further, the image forming unit 401 includes developing units 109a, 109b, 109c, and 109d that develop the electrostatic latent images formed on the photoconductors 108a, 108b, 108c, and 108d.

  The image forming unit 401 also includes an intermediate transfer belt 111 to which toner images formed on the photoconductors 108a, 108b, 108c, and 108d are sequentially transferred, and a toner image on the intermediate transfer belt 111 for transferring to a sheet. A transfer unit 106 is provided.

  A belt conveyance unit 112 that conveys a sheet is provided downstream of the transfer unit 106 in the image forming unit 401 in the sheet conveyance direction. The belt conveyance unit 112 conveys the sheet to the fixing device 402. In the vicinity of the belt conveyance unit 112, a winding storage unit 301 for winding and storing the sheet is provided. The configurations of the belt conveyance unit 112 and the winding storage unit 301 will be described in detail later.

  A fixing device 402 as a fixing unit includes a first fixing unit 113 and a second fixing unit 114 provided side by side in the transport direction. The fixing device 402 is provided with a conveyance path 116 between the first fixing unit 113 and the second fixing unit 114 and a bypass 115 that bypasses the second fixing unit 114.

  The post-conveying unit 403 conveys the post-fixing conveyance path 117 through which the sheet from the fixing device 402 is conveyed, the reverse conveyance path 119 branched from the post-fixing conveyance path 117 and extended downward, and the sheet reversed by the reverse conveyance 119. A double-sided conveyance path 121 for conveyance. A reverse roller 120 is provided in the reverse conveyance path 119, and conveys the sheet conveyed downward along the reverse conveyance path 119 toward the double-sided conveyance path 121. The double-sided conveyance path 121 joins the conveyance unit 103 on the downstream side. The post-fixing conveyance path 117 leads to a discharge conveyance path 118 that discharges the sheet outside the apparatus.

(Description of operation of image forming apparatus)
Next, an image forming operation in the image forming apparatus 100 will be described.

  The sheet S is fed from the sheet feeding unit 101, passes through the conveyance units 103, 104, and 105 and is sent to the transfer unit 106.

  On the other hand, electrostatic latent images are formed on the photoconductors 108a, 108b, 108c, and 108d charged by the laser light including the image information separated into the respective colors from the laser scanners 107a, 107b, 107c, and 107d. The latent images formed on the photoconductors 108a, 108b, 108c, and 108d. Visible toner images are formed by the developing units 109a, 109b, 109c, and 109d. The toner images are transferred so as to be sequentially superimposed on the intermediate transfer belt 111.

  The sheet is transported to the transfer unit 106 by the transport unit 105 so that the leading end of the toner image on the intermediate transfer belt 111 and the leading end of the sheet S meet at the transfer unit 106.

  The sheet S to which the toner image has been transferred is conveyed to the fixing device 402 by the belt conveying unit 112, and the toner image is fixed to the sheet by the fixing device 402.

  Here, when the sheet S is thick paper that cannot be completely fixed by the first fixing unit 113, the sheet S is configured to be completely fixed by passing through the second fixing unit 114 via the inter-fixing conveyance path 116. In the case of a sheet that can be sufficiently fixed only by the first fixing unit 113, the sheet passes through the bypass 115 after passing through the first fixing unit 113.

  The sheet on which the image is fixed by the fixing device 402 is conveyed to the outside of the apparatus through a post-fixing conveyance path 117 and a discharge conveyance path 118.

  When an image is also formed on the back side of the sheet S (double-sided mode), the sheet S on which an image has already been formed and fixed is sent from the post-fixing conveyance path 117 to the reverse conveyance path 119. Then, when the reverse roller 120 is reversed, the reverse roller 120 is sent out to the duplex conveying path 121. The sheet passes through the double-sided conveyance path 121 and then passes through the conveyance units 103, 104, and 105, and an image is formed on the back surface at the transfer unit 106. As in the case of the front side, the image is fixed on the sheet by the first fixing unit 113, and is discharged out of the apparatus through the post-fixing conveyance path 117 and the discharge conveyance path 118.

(Configuration of belt conveyance unit 112 and winding storage unit 301)
Next, the configuration of the belt conveyance unit 112 and the winding storage unit 301 will be described with reference to FIGS.

  First, the belt conveyance unit 112 will be described with reference to FIG. 2 which is a cross-sectional view and FIG. 3 which is a perspective view.

  The belt conveyance unit 112 includes rollers 202, 203, 204, and 205 and a conveyance belt 206 that is wound around the rollers 202, 203, and 204 and rotates. The roller 202 is rotationally driven by a motor 207.

  The belt conveyance unit 112 includes a fan 208 that generates air for adsorbing the sheet to the conveyance belt 206. That is, the fan 208 sucks the sheet S toward the conveying belt 206 and conveys the sheet S by the conveying belt 206 without the turbulence of the sheet S.

  The belt conveyance unit 112 is rotatably provided on the apparatus main body around a rotation fulcrum 201 provided on the upstream side in the sheet conveyance direction, and is rotated by a rotation motor.

  The position of the belt conveyance unit 112 indicated by (1) in FIG. 2 is a steady position for feeding the sheet to the fixing device 402. The position of the belt conveyance unit 112 shown in (2) in FIG. 2 is a staying sheet processing position for processing a sheet on the belt conveyance unit 112 when a jam occurs. In the staying sheet processing position indicated by (2) in FIG. 2, the belt conveyance unit 112 as a transfer unit transfers the sheet to the winding storage unit 301.

  In addition, a sensor 210 for detecting the conveyed sheet is provided at the center of the conveying belt 206. A sensor 210 detects whether there is a sheet on the conveyance belt 206. As shown in FIG. 3, an electromagnetic brake 209 is provided on the roller 202 around which the conveyance belt 206 is wound. The electromagnetic brake 209 is for stopping the conveyance belt 206 immediately when a jam is detected so that the sheet is not caught in the first fixing unit 113.

  Next, the configuration of the winding storage unit 301 for winding and storing the sheet conveyed by the belt conveyance unit 112 will be described with reference to FIGS. 2, 3, and 6 to 8.

  2 is a cross-sectional view, and FIG. 3 is a perspective view. 6 is a longitudinal sectional view, and FIG. 7 is a BB sectional view in FIG. FIG. 8 is a perspective view showing a state when the take-up storage unit 301 is removed from the apparatus main body.

  As shown in FIG. 3, a rear flange 312 is provided on one side of the sheet in the width direction (the back of the apparatus main body), and a front flange 313 is provided on the other side (the front of the apparatus main body). The front flange 313 and the rear flange 312 are connected and integrated by a lever shaft 308.

  Between the rear flange 312 and the front flange 313, there is provided a winding core 303 having a cylindrical shape and disposed so that the direction of the rotation axis coincides with the width direction of the sheet. The winding core 303 is rotatably supported at both ends in the rotation axis direction by a rear flange 312 and a front flange 313, respectively. In the winding core 303, the sheet sent by the belt conveyance unit 112 is wound around the outer periphery.

  A plurality of levers 307 are rotatably attached to the lever shaft 308 between the rear flange 312 and the front flange 313. A roller 306 is rotatably attached to the tip of the lever 307. The roller 306 is provided so as to face the outer peripheral surface of the winding core 303. The lever 307 is biased by a lever biasing spring 309 so that a roller 306 provided at the tip is pressed against the outer periphery of the winding core 303.

  A sheet pressing plate 304 is provided between the belt conveyance unit 112 and the outer periphery of the winding core 303. The sheet pressing plate 304 guides the sheet sent from the belt conveyance unit 112 to the outer periphery of the winding core 303 while suppressing the slack of the sheet. The sheet holding plate 304 is rotatably attached to the rear flange 312 and the front flange 313 with the support shaft 305 as the center. That is, the sheet pressing plate 304 is rotatably attached to a support shaft 305 that is held at both ends by a front flange 313 and a rear flange 312 and is urged toward the winding core 303 by a spring 315. .

  As described above, the front flange 313 and the rear flange 312 are connected and integrated by the lever shaft 308. As shown in FIG. 8, the front flange 313, the rear flange 312, the winding core 303, the sheet pressing plate 304, and the like are integrally formed as a winding unit U in the core direction of the winding core 303 with respect to the apparatus main body. It is removable. A knob 314 is formed on the front flange 313, and the winding unit U can be easily detached to the front side of the apparatus main body (the front side of the image forming apparatus) by operating the knob 314 by the operator.

  The drive motor 310 shown in FIGS. 6 and 8 is a motor that generates a drive for rotating the winding core 303. The drive motor 310 is fixedly disposed on the apparatus main body. A coupling portion 311 that is rotated by a driving force from the driving motor 310 is fixedly provided on the apparatus main body. The inner peripheral surface of the winding core 303 is detachably fitted into the cylindrical protruding portion 3111a of the coupling portion 311. With this configuration, the rotational driving force from the drive motor 310 is transmitted to the winding core 303.

  As shown in FIG. 6, a rotation support member 316 that rotatably supports the end of the winding core 303 is attached to the surface of the front flange 313 on the winding core 303 side. The rotation support member 316 urges the winding core 303 toward the coupling portion 311 by a coupling spring 317. When the winding core 303 is urged toward the coupling portion 311, the winding core 303 and the coupling portion 311 are coupled, and the drive from the drive motor 310 is reliably transmitted to the winding core 303.

  FIG. 5 is a control block diagram relating to the winding operation of the staying sheet. The main controller 411 controls the control. The main controller 411 is connected to a plurality of detection sensors that are provided in each conveyance path of the apparatus main body and detect a sheet and a sensor 210 of the belt conveyance unit. Further, the main controller 411 controls the driving operation of a rotation motor for rotating the belt conveyance unit 112 and a motor 207 for rotating the belt of the belt conveyance unit 112. Further, the main controller 411 controls operations of the fan 208 and the electromagnetic brake 209 in the belt conveyance unit 112. Further, the main controller 411 controls the operation of the drive motor 310 of the winding storage unit 301.

(Explanation of operations of the belt conveyance unit 112 and the winding storage unit 301)
When the main controller 411 serving as the control unit determines that a jam has occurred in the apparatus main body based on the output from the detection sensor in the conveyance path, the main controller 411 stops the sheet conveyance in each conveyance unit of the apparatus main body. Here, when the main controller 411 determines that there is a staying sheet stopped before the leading end of the belt transport unit 112 reaches the first fixing unit 113, the main controller 411 takes up the staying sheet on the belt transport unit 112. The operations of the winding storage unit 301 and the belt conveyance unit 112 are controlled so as to be stored in the storage unit. That is, the main controller 411 causes the belt conveyance unit 112 and the winding storage unit 301 to perform the following operation for winding and storing the staying sheet according to the occurrence of the jam.

  That is, the main controller 411 controls the rotation motor to move the belt conveyance unit 112 to the staying sheet processing position in (2) of FIG. 2 and sends the sheet to the winding storage unit 301 by the belt conveyance unit 112. Make it. Further, the main controller 411 rotates the drive motor 310 of the winding storage unit 301 so that the sheet transferred by the belt conveyance unit 112 is wound around the outer periphery of the winding core 303.

  When the drive motor 310 rotates, the winding core 303 rotates in the clockwise direction in FIG. The sheet conveyed by the belt conveyance unit 112 is wound around the outer periphery of the winding core 303 while being pressed against the outer periphery so as not to be separated from the outer periphery of the winding core 303 with a sheet pressing plate 304 and a roller 306 as pressing members. it can. The take-up storage unit 301 can take up a plurality of sheets on the outer periphery thereof.

Next, the operation at the time of jam will be described with reference to the flowchart of FIG.
Step 1: The main controller 411 determines that a jam has occurred based on the output from the detection sensor while the image forming apparatus 100 is in operation.
Step 2: When the main controller 411 determines that a jam has occurred, the main controller 411 stops the image forming apparatus. That is, the image forming operation in the image forming unit and the sheet conveyance in the apparatus are stopped. Here, the main controller 411 immediately stops the conveyance of the sheet by operating the electromagnetic brake 209 so that the sheet is not caught in the first fixing unit 113 with respect to the belt conveyance unit 112 before fixing.
Step 3: The main controller 411 determines whether there is a staying sheet on the belt conveyance unit 112 based on an output from the sensor 210 arranged in the belt conveyance unit 112. If the main controller 411 determines that the staying sheet is on the belt conveyance unit 112, the process proceeds to step 4. If the main controller 411 determines that the staying sheet is not on the belt conveyance unit 112, the process proceeds to step 7.
Step 4: The main controller 411 is used for rotation so that the belt conveyance unit 112 moves to a staying sheet processing position that rotates in the direction of arrow A in FIG. 2 and enters the sheet into the winding port 302 of the winding storage unit 301. Control the motor.
Step 5: The main controller 411 releases the operation of the electromagnetic brake 209 and drives the motor 207 again so that the belt conveying unit 112 conveys the sheet. At the same time, in the main controller 411, the winding core 303 is rotated by the drive motor 310, and the sheet is wound.
Step 6: After driving the drive motor 310 and the motor 207 for a predetermined time so that the sheet is wound on the winding core 303, the main controller 411 stops the rotation of the drive motor 310.
Step 7: The main controller 411 controls the motor for rotation so that the belt conveyance unit 112 returns to the original steady position.
Step 8: Return to the standby state for the next image formation.

  In this way, when a jam occurs, the sheet staying on the belt conveyance unit 112 is taken up by the take-up storage unit 301 and discharged from the belt conveyance unit 112.

  As described above, when a jam occurs, the sheet staying in the apparatus main body is automatically wound and stored in the winding storage unit 301. Since the take-up storage unit 301 winds and stores the sheet, the space for storage can be reduced, so that a small device can be provided. Since the sheet on the belt conveyance unit 112 on which an unfixed image may be placed is automatically moved to a position that does not interfere with the subsequent operation of the apparatus, the apparatus operation can be resumed quickly. Further, it is possible to take out the sheet wound around the take-up storage unit 301 at any time after the operation of the apparatus is resumed, and the downtime of the apparatus can be shortened.

  Further, since the sheet staying on the conveying belt 206 is wound and stored, when the sheet is removed, unfixed toner is prevented from adhering to hands, clothes, a conveying path and its peripheral members, and dirt in the apparatus is prevented. Deterioration can be prevented. Further, the image forming process can be restarted while the sheet is wound and stored in the winding storage unit 301 as a winding storage unit.

  Removing the winding unit U of the winding storage unit 301 from the apparatus main body while leaving the coupling unit 311 and replacing the winding core 303 to take out the wound sheet to the outside of the apparatus. Is possible (see FIG. 8). The removed winding core 303 can be mounted again. That is, the sheet wound around the winding core 303 can be taken out of the apparatus while being wound around the winding core 303. Therefore, when the sheet is taken out from the apparatus and processed, the hands and the inside of the apparatus are not soiled. The take-up unit U can be detached from the apparatus main body even when the image forming apparatus 100 is in operation (during the image forming operation).

  Since the winding storage unit 301 starts winding the sheet so that the unfixed toner surface of the sheet faces the outer periphery of the winding core 303, the sheet is wound by the winding core 303. When attaching and detaching the toner, there is less risk of smearing hands with toner.

  In the above-described embodiment, the configuration in which only the staying sheet on the belt conveyance unit 112 is wound on the winding storage unit 301 is illustrated. However, the sheet staying in the conveying units 105 and 104 on the upstream side of the belt conveying unit 112 may be controlled to be sequentially stored in the winding and storing unit 301 by driving the conveying units 105 and 104.

  In addition, after performing the process of winding the sheet staying in the belt conveyance unit 112 in the winding storage unit 301 and returning to the standby state and resuming image formation in step 8, it is set so that jam recovery is performed. It may be. With this setting, for jobs that were set before the occurrence of a jam, image formation for sheets other than the sheets that were formed and discharged before the occurrence of the jam is performed again, and the paper is discharged normally before the occurrence of the jam first. It is possible to complete the job together with the printed sheet.

  Of the sheets remaining in the apparatus at the time of jamming, the sheets in the conveying units 104 and 105 that have not yet been transferred with the toner image on the surface are not taken up by the take-up storage unit 301. Then, after entering the standby state, the transfer unit 106 may normally convey the sheets in the conveyance units 104 and 105 so as to match the writing timing of the laser scanner, and form an image on the sheet. With this configuration, waste of sheets can be eliminated.

1 is a schematic sectional view of an image forming apparatus according to an embodiment of the present invention. The fragmentary sectional view of the winding storage part and conveyance part which concern on embodiment of this invention. The perspective view of the winding storage part and belt conveyance unit which concern on embodiment of this invention. The flowchart figure explaining operation | movement. The block diagram for demonstrating a control structure. Sectional drawing of the longitudinal direction of the winding storage part which concerns on embodiment of this invention Sectional drawing (cross section BB shown in FIG. 5) of the winding storage part which concerns on embodiment of this invention The perspective view of the winding storage part and belt conveyance unit of the embodiment of the present invention

Explanation of symbols

112 Belt Conveying Unit 301 Winding Storage Unit 303 Winding Core 304 Sheet Holding Plate 308 Lever Shaft 312 Rear Flange 313 Front Flange 401 Image Forming Unit 402 Fixing Device

Claims (7)

A transfer portion for transferring the toner image to the sheet;
Fixing means for fixing the toner image transferred by the transfer unit to the sheet;
A take- up storage that winds and stores the sheet , and includes a winding core that is rotationally driven to wind the conveyed sheet around the outer periphery, and a pressing unit that presses the wound sheet against the outer periphery of the winding core. Means,
The sheet is stopped before the leading edge of the sheet reaches the fixing unit, the image forming apparatus characterized by having a transfer means for transferring to said take-up storage unit. The image forming according to claim 1, characterized in that the winding accommodation portion as the surface of the sheet is opposed to the outer periphery of the winding core is transferred to the image by the transfer portion starts the winding of the sheet apparatus. The image forming apparatus according to claim 1 or 2, characterized in that the winding core is detachable from the apparatus main body in a state where the sheet is wound around the outer peripheral. The transfer means is supported rotatably around a rotation fulcrum, a conveyance belt that conveys the sheet from the transfer unit to the fixing means, and a position that conveys the conveyance belt to the fixing means, A rotation means for rotating about the rotation fulcrum between a position for conveying the sheet to the winding storage means ,
The rotation means may, when performing image formation, the conveying belt, is positioned at a position for conveying the sheet to the fixing unit, sometimes jam occurs, to a position for transporting the sheet to the take-up housing means the image forming apparatus according to any one of claims 1 to 3, wherein Rukoto is rotated. The image forming apparatus according to claim 4, further comprising a sensor configured to detect whether a sheet is present on the conveyance belt. The image forming apparatus according to claim 1, further comprising a motor that rotates the winding core. The pressing portion is provided between the conveyor belt and the outer periphery of the winding core, and includes a pressing member that guides the sheet conveyed from the conveying belt to the outer periphery of the winding core, and the pressing member. The image forming apparatus according to claim 4, further comprising an urging spring that urges the winding core.

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