JP2009102111A - Sheet processing device and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sheet processing device preventing adhesion between sheets and improving accuracy of rear end alignment of the sheet in the sheet processing device for moving the sheet to an upstream side by pushing the sheet sgainst a tray to align the rear end of the sheet. <P>SOLUTION: The sheet processing device 400 is provided with the processing tray 410 on which the sheet having a toner image fixed by heating is stacked, an offset roller 407 for moving the sheet stacked on the processing tray to the upstream side of the sheet conveying direction by pushing against the processing tray, and a rear end aligning part 411 for receiving the upstream end of the sheet moved to the upstream side by the offset roller and aligning the upstream end. The sheet stacked on the processing tray passes over the rear end aligning member. A cooling device 610 is provided for supplying air to a space between a lower surface of the sheet passing over the rear end aligning member and the processing tray to cool the sheet. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a sheet processing apparatus that prevents sheets from adhering to each other by the toner of the toner image by cooling the sheets when stacking sheets on which toner images are heat-fixed, and the sheet processing apparatus to the apparatus main body. The present invention relates to an image forming apparatus provided.

  2. Description of the Related Art Conventionally, there is a sheet processing apparatus that stacks sheets discharged from an apparatus main body of an image forming apparatus such as a copying machine, a printer, a facsimile machine, and a multi-function machine one by one on a tray that is a sheet stacking unit. The sheet processing apparatus may be equipped as one of the components of the image forming apparatus in the apparatus main body or may be equipped as a purchase option (so-called option). The sheet processing apparatus may be externally attached to the apparatus main body of the image forming apparatus or may be incorporated into the apparatus main body.

  Since the sheet discharged from the image forming apparatus is heated by the fixing device to fix the toner image, the sheet is heated. On the other hand, in recent years, high-speed image forming apparatuses exceeding 100 sheets per minute have been put into practical use. When a large number of sheets are stacked on the tray, heat is trapped in the stacked sheets, and the temperature of the sheet heated by the fixing device is difficult to decrease, and it takes time for the toner of the toner image to harden. For this reason, there is a possibility that the sheets adhere to each other with toner.

  A sheet processing apparatus that copes with such a problem is disclosed in Japanese Patent Application Laid-Open No. H10-228707. In this sheet processing apparatus, air is blown onto the upper surface of a sheet stacked on the tray from an air cooling device disposed above the tray to cool the sheet.

  By the way, in the sheet processing apparatus, the sheet is pressed against the tray and moved to the upstream side, the trailing end (upstream end) of the sheet is brought into contact with the alignment member to be aligned at the trailing end, and the bundle is processed. There are models that drill holes or only rear end alignment.

JP 2007-79310 A

  However, it is difficult for the sheet processing apparatus for aligning the trailing edges of the sheets to align the trailing edges of the sheets when the sheets adhere to each other with toner. In particular, since the sheets are pressed against the tray, the sheets easily adhere to each other, and the rear end alignment of the sheets is more difficult.

  Therefore, as in the conventional sheet processing apparatus of Patent Document 1, even when air is blown onto the upper surface of the sheet and the sheets are cooled by the air cooling apparatus, the sheets are pressed against each other, thereby preventing adhesion between the sheets. I could not. As a result, it is difficult for the sheet processing apparatus that performs rear end alignment to perform rear end alignment.

  In addition, when the air cooling device is provided above the tray as in the sheet processing device disclosed in Patent Document 1, it is difficult to remove the sheets stacked on the tray.

  Further, the image forming apparatus provided with the sheet processing apparatus in which the sheets easily adhere to each other has to form an image again on the adhered sheets if the sheets adhere to each other, and the image forming efficiency is low.

  The present invention relates to a sheet processing apparatus that presses a sheet against a tray and moves the sheet upstream to align the trailing edge of the sheet, and prevents the sheets from adhering to each other to improve the accuracy of sheet trailing edge alignment. It is to provide a processing apparatus.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an image forming apparatus that includes a sheet processing apparatus that prevents adhesion between sheets, reduces image formation of the adhered sheets again, and increases image formation efficiency.

  The sheet processing apparatus according to the present invention includes a sheet stacking unit on which a sheet on which a toner image is heat-fixed is stacked, and the sheet stacked on the sheet stacking unit is pressed against the sheet stacking unit to the upstream side in the sheet conveying direction. A sheet conveying unit that moves, and an upstream end alignment member that receives the upstream end of the sheet moved to the upstream side by the sheet conveying unit and aligns the upstream end, and is stacked on the sheet stacking unit A sheet processing apparatus that passes over the upstream end alignment member, and cools the sheet by sending air between the lower surface of the sheet passing over the upstream end alignment member and the sheet stacking means. It is characterized by having means.

  An image forming apparatus according to the present invention includes: an image forming unit that forms an image on a sheet; and a sheet processing device that processes a sheet on which an image has been formed by the image forming unit. It is a processing device.

  The sheet processing apparatus of the present invention cools the sheet by sending air between the lower surface of the sheet passing over the upstream end alignment member and the sheet stacking unit by the cooling unit. It is possible to prevent the toner from adhering. Further, the sheet can be transported smoothly by the sheet transporting unit which can prevent the sheets from adhering to each other, and the accuracy of rear end alignment of the sheet can be improved.

  Since the image forming apparatus of the present invention includes the sheet processing apparatus that prevents the sheets from adhering to each other, it is possible to increase image forming efficiency by reducing the image formation of the adhered sheets again.

  Hereinafter, a sheet processing apparatus according to an embodiment of the present invention and an image forming apparatus including the sheet processing apparatus, for example, a copier, will be described with reference to the drawings. However, although the sheet processing apparatus of the present invention performs stapling, it may be configured to perform processing such as simply stacking sheets, perforation processing, and the like. The image forming apparatus of the present invention is not limited to a copying machine, and may be a facsimile, a printer, a complex machine of these, or the like.

  In addition, the sheet processing apparatus 400 of the present embodiment in FIG. 1 is provided as one of the components of the copying machine in the apparatus main body 500 of the copying machine A, but is provided as a purchase option (so-called option). , You may be able to handle it alone. Further, the sheet processing apparatus is incorporated in the apparatus main body 500 of the copying machine, but may be externally attached to the apparatus main body of the copying machine.

(Copier)
FIG. 1 is a cross-sectional view of a copying machine provided with a sheet processing apparatus according to an embodiment of the present invention along the sheet conveying direction. For example, the copier A that is an image forming apparatus of the present invention includes, for example, a printer unit 200 that is an image forming unit, and a sheet processing apparatus 400.

  In the copying machine A, a reader unit 120 that reads an image of a document and a printer unit 200 that forms an image are combined in an apparatus main body 500. In the space SP provided in the apparatus main body 500, a sheet processing apparatus 400 for aligning and stapling sheets on which images are formed is disposed. An automatic document feeder (hereinafter referred to as “ADF”) 300 that supplies documents one by one onto the platen glass 102 is attached to the upper portion of the apparatus main body 500 so as to be openable and closable rearward. The ADF 300 is not necessarily provided. The reader unit 120, the printer unit 200, and the ADF 300 of the copying machine A are controlled by the CPU 100 of the copying machine.

  As shown in FIG. 10, an inlet sensor 403 and a sheet bundle discharge sensor 415 are connected to the CPU 101 of the sheet processing apparatus. A conveyance motor 431, an offset motor 432, a sheet bundle discharge motor 430, an air path changing plate motor 605, a pickup solenoid 433, a clamp solenoid 434, a stapler unit 420, and a cooling fan 601 are connected to the CPU 101.

  The copying machine A receives image data sent from an external personal computer or the like by the printer unit 200 in addition to the function of a copying machine that copies the original image read by the reader unit 120 to a sheet by the printer unit 200, and receives the sheet data. It also has a function as a printer for printing images. Further, the copying machine A transmits a facsimile signal as an image signal of an original image read by the reader unit 120, or receives a facsimile signal from another facsimile and prints it by the printer unit 200. It also has a function as. The copying machine A may have only the function of the copying machine.

  When copying images of a plurality of originals, when the originals are stacked on the ADF 300, the ADF 300 sequentially conveys the originals one by one onto the platen glass 102 of the reader unit 120 and stops in advance. Pass above. When copying an image of a document that cannot be handled by the ADF 300, the ADF 300 is opened rearward, the document is directly placed on the platen glass 102, and the scanner unit 104 is moved in the horizontal direction in the drawing. In any case, the image of the band-like area illuminated by the lamp of the scanner unit 104 is imaged on the CCD image sensor unit 109 through the mirrors 105, 106, 107 and the lens 108, and as a line image by the CCD image sensor unit 109. Read. The line image is photoelectrically converted into an image signal by the CCD image sensor unit 109 and subjected to digital processing such as image data conversion and image processing.

  The digitally processed image signal is transmitted to the exposure control unit 201 of the printer unit 200 and converted into an optical signal of a modulated laser beam. The exposure control unit 201 scans the optical signal to irradiate the photosensitive drum 202, and forms an electrostatic latent image on the surface of the photosensitive drum 202. The electrostatic latent image is developed with toner by the developing unit 203 to become a toner image, which is visualized.

  On the other hand, the sheets S of the sheet cassettes 204 and 205 are sent out from the sheet cassettes 204 and 205 in synchronization with the leading ends of the toner images, and the toner images are transferred by the transfer unit 206. The sheet S to which the toner image is transferred is heated and pressed by the fixing device 207, and the toner image is heated and fixed. The sheet S heated by the fixing device 207 is delivered to the sheet processing apparatus 400 through the sheet discharge unit 208. The distance between the fixing device 207 and the sheet discharge unit 208 is short, and the sheet is fed into the sheet processing apparatus 400 without sufficiently releasing the heat heated by the fixing device 207.

(Sheet processing equipment)
FIG. 2 is a cross-sectional view of the main part of the sheet processing apparatus as viewed from the front side. FIG. 3 is a plan view of FIG. FIG. 4 is a diagram for explaining the operation of supplying sheets to the processing tray. FIG. 5 is a diagram for explaining the operation of bringing the upstream end (rear end) of the sheet into contact with the rear end alignment member 411 for alignment.

  In the following description, the rear end of the sheet is an upstream end in the sheet conveyance direction (arrow B direction) in FIG. 5 and is a portion indicated by reference numeral Sa. Further, as shown in FIG. 3, the side edge of the sheet refers to an edge along the sheet conveyance direction (arrow B), and refers to a portion indicated by reference numeral Sb.

  The sheet processing apparatus 400 mainly includes the following components. For example, a processing tray 410 that is a sheet stacking unit on which a sheet on which a toner image is fixed by being heated by the fixing device 207 (FIG. 1) is stacked. For example, an offset roller 407 that is a sheet conveying unit that presses the sheets stacked on the processing tray 410 against the processing tray 410 and moves the sheets to the upstream side in the sheet conveying direction. An upstream end alignment member 411 that is an upstream end alignment member that receives the upstream end (rear end) Sa (FIG. 5) of the sheet moved to the upstream side by the offset roller 407 and aligns the upstream end, for example. For example, a sheet cooling device 610 (FIG. 6) which is a cooling unit that cools the sheet by sending air between the lower surface of the sheet stacked on the processing tray 410 and the processing tray 410 after passing over the trailing edge alignment member 411. . A CPU 101 that controls the sheet processing apparatus 400. The CPU 101 of the sheet processing apparatus and the CPU 100 of the copying machine may be integrated by incorporating one into the other.

  The sheet processing apparatus 400 is accommodated in a space SP formed on the side of the apparatus main body 500 of the copying machine A without protruding from the apparatus main body 500 of the copying machine. The sheet processing apparatus 400 stacks sheets received from the sheet discharge unit 208 on the processing tray 410 (FIGS. 2 and 3) and sorts them, or staples them using the stapler unit 420, and stacks them into a bundle. The paper is discharged to the tray 421.

  A rail member 440 is provided below the sheet processing apparatus 400. The sheet processing apparatus 400 can replenish the staples to the stapler unit 420 (FIG. 3) when the rail member 440 is guided and pulled out obliquely with respect to the transport direction.

(Overview of operation of sheet processing apparatus 400)
The sheet processing apparatus 400 stacks the sheets S received through the sheet receiving unit 401 on the processing tray 410. Then, the sheet processing apparatus 400 reversely feeds the sheet by the rotation of the offset roller 407, abuts the trailing edge of the sheet against the trailing edge alignment member 411, and aligns the trailing edge of the sheet. Thereafter, the offset roller 407 moves in the sheet width direction, moves the sheet in the width direction, abuts against the side edge alignment member 416, and performs side edge alignment. The sheet processing apparatus 400 performs this operation every time a sheet is sent. When the succeeding sheet is fed into the processing tray 410, the preceding sheet may be pushed downstream by the succeeding sheet, and rear end alignment may be disturbed. For this reason, each time a subsequent sheet is fed, the gripper 412 holds the preceding sheet so that the alignment of the preceding sheet is not disturbed. When the number of sheets successively sandwiched between the grippers 412 becomes a number of sheet bundles corresponding to the number of document sheets, the sheet processing apparatus 400 binds (staps) the sheet bundles with the stapler unit 420 (FIG. 3). Finally, the sheet processing apparatus pushes and discharges the sheet bundle to the stack tray 421 by the movement of the sheet bundle discharge member 413.

  The stack tray 421 is provided with an elevating drive device including a motor (not shown), and moves up and down the space below the processing tray 410 to stop positioning at an arbitrary height. In the process of stacking and aligning sheets on the processing tray 410, the stack tray 421 rises to the vicinity of the processing tray 410 and stands by so as to support the leading end side of the sheet bundle stacked on the processing tray 410. When the sheet bundle is stacked on the stack tray 421, the stack tray 421 is lowered by the thickness of the sheet bundle so that the upper surface of the sheet bundle becomes the same height as the upper surface of the processing tray 410. Wait so that the sheet bundle can be easily stacked.

(Description of sheet trailing edge alignment operation of sheet processing apparatus and description of structure related to this operation)
As shown in FIG. 2, the offset roller 407 is formed in a cylindrical shape with an elastic material such as rubber or a resin foam having elasticity close to that of a rubber on the outer periphery. The offset roller 407 is pivotally supported by a rotation end of an offset roller holder 406 that can rotate integrally with a rectangular offset shaft 511. The offset roller holder 406 is configured to rotate integrally with the rectangular offset shaft 511 and move on the offset shaft 511.

  When the pickup solenoid 433 is turned ON / OFF, the offset shaft 511 is rotated via the solenoid arm 512 and the separation lever 514, and the offset roller 407 is moved up and down by the offset roller holder 406.

  As shown in FIG. 3, the offset roller 407 is rotated by a transport motor 431 capable of rotating forward and reverse that rotates the transport roller pair 405. The rotational force of the transport motor 431 is transmitted to the timing belt 522 via the belt 523, the roller gear 524, the idler gear 525, the offset gear 526, the offset shaft 511, and the offset pulley 527a. The rotational force is further transmitted to the offset roller shaft 550 via the offset pulley 527b and finally to the offset roller 407.

  The offset roller holder 406 is raised and rotated to the position shown in FIG. 4 by the ON operation of the pickup solenoid 433 to separate the offset roller 407 from the processing tray 410. The sheet receiving unit 401 (FIG. 2) receives the sheet S discharged from the sheet discharge unit 208 (FIG. 1) of the apparatus main body 500. After the leading edge of the sheet S received by the sheet receiving unit 401 is detected by the inlet sensor 403, the sheet S is conveyed by the conveying roller pair 405 and sent to the processing tray 410 (FIG. 4).

  Thereafter, the pickup solenoid 433 is turned off, and the offset roller holder 406 is dropped and rotated by its own weight as shown in FIG. 5 to bring the offset roller 407 into contact with the sheet S on the processing tray 410. As shown in FIG. 5, the offset roller 407 descends and presses the sheet S against the processing tray 410, and is rotated clockwise (arrow A direction) by the transport motor 431, and the sheet S is downstream (arrow B direction). Carry further.

  When the trailing edge of the sheet S passes through the pair of conveying rollers 405 and gets on the processing tray 410, for example, a sheet bundle discharge sensor 415 (FIG. 4) serving as a detection unit is pushed in by the sheet, and the sheet is placed on the processing tray 410. It is detected that S is loaded. Thereafter, as shown in FIG. 5, the offset roller 407 reverses in the direction of arrow C, conveys the sheet S to the upstream side (in the direction of arrow D), and abuts the trailing edge of the sheet against the trailing edge alignment member 411. At this time, a gripper 412 described later is opened to receive the trailing edge of the sheet.

  As a result, the trailing edge of the sheet is received by the trailing edge alignment member 411, and the trailing edge of the sheet is aligned.

(Description of sheet side edge alignment operation of sheet processing apparatus and structure related to this operation)
The offset rack 515 (FIG. 3) reciprocates in the sheet width direction (arrow K direction) on the long support member 516 by the rotation of the offset motor 432 and the offset motor gear 432a. Note that the offset rack 515 shown in FIG. 5 is located farthest from the stapler unit 420. The offset rack 515 has a connecting member 517. The connecting member 517 is provided on the offset shaft 511 having a square axis shape via a round hole (not shown), and is positioned inside the offset roller holder 406. For this reason, when the offset rack 515 moves, the offset roller holder 406 moves in the width (arrow K) direction on the angular offset shaft 511. When the offset shaft 511 rotates, the offset roller holder 406 rotates, but the connecting member 517 does not rotate.

  The offset roller 407 (FIG. 3) moves in the direction along the offset shaft 511, that is, in the width direction of the sheet S in accordance with the normal rotation and reverse rotation of the offset motor 432, and approaches the side end alignment member 416. It is going away. The side end alignment member 416 is provided upright on the edge of the processing tray 410 on the stapler unit 420 side, and regulates the position of the end in the sheet width direction. That is, the side edge alignment member 416 receives and aligns the side edges of the sheet.

  The sheet pressing member 600 includes a contact piece 600a that is provided on the fixed shaft 600b so as to be rotatable in the vertical direction and that contacts the separation lever 514. For this reason, the sheet pressing member 600 is lifted and lowered in the same manner as the offset roller holder 406 by the offset roller holder 406 that moves up and down as the pickup solenoid 433 is turned on and off, thereby preventing the sheet from being lifted. ing.

  The offset roller 407 that has finished the trailing edge alignment of the sheet moves in the sheet width direction (arrow K direction) by the rotation of the offset motor 432 while pressing the sheet against the processing tray 410, and moves the sheet S to the side edge. It abuts against the alignment member 416. As a result, the sheet is aligned with the rear end and the side end of the sheet.

  As shown in FIG. 2, the sheet bundle discharge member 413 has a gripper 412 so as to be rotatable, and is attached to the processing tray 410 so as to be movable along the sheet conveying direction. The gripper 412 is disposed adjacent to the rear end alignment member 411 and sandwiches the rear end of the sheet S aligned by the rear end alignment member 411 so as to position and fix the sheet S on the processing tray 410. .

  The gripper 412 is urged in a direction to sandwich the sheet by a spring (not shown), and is opened against the spring when the clamp solenoid 434 is turned on. The clamp solenoid 434 is turned on when the offset roller 407 conveys the sheet to the downstream side and stops rotating, or when the offset roller moves in the sheet width direction, and the gripper 412 is moved upward via the lever 434a. It is designed to rotate and open. Therefore, the gripper 412 is open when the sheet is moved upstream and approaches the rear end alignment member 411 and when the sheet approaches the side end alignment member 416.

  When the next succeeding sheet S is supplied on the stacked sheet (preceding sheet) on the processing tray 410 and the succeeding sheet is conveyed downstream by the offset roller 407, the preceding sheet follows the succeeding sheet and is downstream. The position may be shifted to the side. Therefore, the gripper 412 grips the preceding sheet when the succeeding sheet is fed, and prevents the positional deviation of the preceding sheet. Thus, a sheet bundle is formed on the processing tray 410 by the rotation operation of the offset roller 407, the operation of moving the sheet in the width direction, and the opening / closing operation of the gripper 412. When the number of sheets successively sandwiched between the grippers 412 becomes the number of sheets corresponding to the number of documents, the sheet processing apparatus 400 binds (staps) the sheet bundle with the stapler unit 420.

(Description of sheet bundle discharging operation of sheet processing apparatus and structure related to this operation)
The sheet bundle discharge member 413 is normally fixed at the home position by excitation of the sheet bundle discharge motor 430. The sheet bundle discharge member 413 receives the power of the sheet bundle discharge motor 430 via the pinion 435 and the rack 436, so that the sheet is discharged to the stack tray 421 and the home position near the rear end alignment member 411. It is designed to reciprocate between.

  When the sheet bundle is bound, as shown in FIG. 2, the sheet bundle discharge member 413 moves along the processing tray 410 toward the stack tray 421 while the rear end of the sheet bundle is sandwiched between the grippers 412. The sheet bundle is pushed out from the processing tray 410 to the stack tray 421 and discharged. Note that the sheet bundle may be discharged without binding. Further, the sheet bundle may be discharged only by rear end alignment.

(Description of sheet cooling device)
The sheet cooling device 610 will be described with reference to FIGS. In general, as the sheet conveyance speed increases, the sheet conveyance interval becomes narrower. Further, when the sheet conveyed by the sheet processing apparatus is heated by the fixing device 207 (FIG. 1), the sheet is discharged onto the processing tray 410 and pressed against the processing tray by the offset roller 407. It may stick to the preceding sheet due to the pressing force. In this case, sheet misalignment occurs. In addition, the quality of the toner image is degraded.

  Therefore, the sheet processing apparatus of the present invention includes a sheet cooling device 610 that cools the sheet, as shown in FIG. The sheet cooling device 610 is a cooling fan 601 that is disposed below the conveyance guide 602 that guides the lower surface of the sheet inside the sheet processing device 400 and upstream of the rear end alignment member 411. The lower surface of the sheet passing above is cooled. The cooling fan 601 forms cooling air 601a that goes in the sheet conveyance direction by the sucked suction air 601c, and efficiently cools the sheets that are discharged and stacked on the processing tray 410.

  6 and 7, the rear end alignment member 411 is formed with a plurality of, for example, discharge ports 411a that are air discharge ports at a predetermined interval. An air duct 603 is formed above the cooling fan 601 by a conveyance guide 602. In the air duct 603, for example, an air path changing plate 604 that is an air path switching member that changes the direction of the suction air 601c sucked by the cooling fan 601 is disposed.

  As shown in FIG. 6, the air path change plate 604 rotates to a position indicated by reference numeral 604 b around the rotation shaft 604 a to form a downstream air duct 603 a inside the air duct 603. Yes. Further, as shown in FIG. 8, the air path changing plate 604 is configured to form an upstream air duct 603b by rotating around a rotation shaft 604a to a position indicated by reference numeral 604c. Thus, the air path change plate 604 selects the cooling fan suction air 601c as the first air duct, for example, the downstream air duct 603a and the second air duct, for example, the upstream air duct 603b. It is designed to guide you.

  Also, as shown in FIG. 9 which is a cross-sectional view taken along the line AA in FIGS. A plurality of slits 602a as flow paths are provided. For this reason, after the sheet is continuously conveyed into the sheet processing apparatus 400, the inside of the sheet processing apparatus 400 that has accumulated heat by heat radiation from the high-temperature sheet after fixing can be efficiently cooled. As a result, the temperature rise of the sheet sent in the next job setting can be minimized.

  The above-described ON / OFF control of the cooling fan 601 by the CPU 101 and the downstream / upstream air duct switching control by the air path changing plate 604 are the sheet bundle discharge shown in FIG. 4 that the sheets are stacked on the processing tray 410. This is performed by the detection operation of the sensor 415.

  As shown in FIG. 6, when the sheet bundle discharge sensor 415 in FIG. 4 detects that the first sheet S has been conveyed into the sheet processing apparatus 400 and has been stacked on the processing tray 410, the CPU 101 The cooling fan 601 is rotated. At approximately the same time, the CPU 101 rotates the air path changing plate motor 605 shown in FIG. 9 and rotates the air path changing plate 604 in the air duct 603 by rotating the motor gear 605a so that the downstream air duct 603a is moved. Form.

  In this way, when the downstream air duct 603a is formed, the cooling air 601a is blown from the discharge port 411a of the rear end alignment member 411 toward the sheet S conveyance direction with respect to the sheet S to be aligned on the processing tray 410. be able to. As a result, the upper surface of the already stacked sheets S on the processing tray 410 and the lower surface of the next sheet S to be conveyed can be efficiently and simultaneously cooled.

  As described above, when the cooling air 601a of the cooling fan 601 is blown from the discharge port 411a of the rear end alignment member 411, the offset roller 407 mainly cools the vicinity of the pressure contact position to the sheet pressed against the processing tray 410. can do. The pressing force of the offset roller 407 can prevent the sheets from sticking to each other, and the sheets can be reliably aligned. In addition, damage to the sheet can be reduced.

  The sheet cooling operation described above is continued until the job arbitrarily set by the user is completed and the sheet bundle discharge sensor 415 detects that there is no sheet stacked on the processing tray 410.

  When the job is completed, the CPU 101 reverses the air path change plate motor 605 and the motor gear 605a shown in FIG. 9 and rotates the air path change plate 604 to the position indicated by reference numeral 604c shown in FIG. 603b is formed.

  Thereafter, the suction air 601c sucked by the cooling fan 601 is discharged as cooling air 601b from a plurality of slits 602a formed in the conveyance guide 602. The cooling air 601b can efficiently cool the inside of the sheet processing apparatus 400 (in the vicinity of the sheet receiving unit 401) that has accumulated heat by radiating the sheet after continuously conveying a high-temperature sheet.

  In this way, the sheet cooling device 610 cools the inside of the sheet processing apparatus 400, so that the heat storage in the sheet processing apparatus 400 can be cooled in advance before the next job arbitrarily set by the user is started. As a result, the sheet cooling apparatus 610 can suppress the temperature rise of the sheet of the next job sent from the apparatus main body of the copying machine A into the sheet processing apparatus, and helps the cooling operation of the downstream air duct. Thus, it is possible to reliably align the sheets on the processing tray.

  In addition, when the upstream air duct 603b is formed, the rotating cooling fan 601 continues to rotate for about 10 minutes as it is inside the sheet processing apparatus 400 when there is no next job set by the user. Cool down and stop. If the user sets the next job while the sheet processing apparatus 400 is being cooled by the upstream air duct 603b, the cooling fan 601 stops rotating.

  Thereafter, when the sheet bundle discharge sensor 415 detects that the sheet is conveyed to the sheet processing apparatus 400 and stacked on the processing tray 410, the air path change plate 604 is switched to form the downstream air duct 603a. . At the same time, the cooling fan 601 resumes rotation and starts cooling the sheets stacked / discharged on the processing tray 410.

  As described above, in the sheet processing apparatus of the present embodiment, when a sheet is supplied onto the processing tray, the sheet cooling fan starts the air blowing operation based on the sheet bundle detection operation of the sheet bundle discharge sensor 415. It has become. At the same time, the downstream side air duct 603a is formed by the air path changing plate 604, thereby cooling the upper surface of the sheets stacked on the processing tray.

  In addition, by continuously cooling the lower surface of the next sheet conveyed on the processing tray by blowing air from the cooling fan, the upper surface of the already stacked sheets on the processing tray causing the sticking between the sheets, and The lower surface of the conveyed next sheet can be cooled at the same time.

  Thereby, the sheet processing apparatus can intensively cool the vicinity of the press-contact position of the offset roller to the sheet when aligning the sheets stacked on the processing tray. As a result, the sheet processing apparatus can prevent the sheets stacked on the processing tray from adhering to each other due to the pressure contact force in the alignment operation of the offset roller (discharge adhesion), and can be aligned on the processing tray. It is possible to prevent occurrence of sheet misalignment during processing.

  Further, when the sheet processing apparatus discharges the aligned sheet bundle on the processing tray to the stack tray 421 and empties the processing tray, the sheet bundle discharge sensor 415 detects the empty state and tilts the air path changing plate 604. Thus, an upstream air duct 603b is formed.

  As a result, the sheet processing apparatus switches the air flow blown from the cooling fan from the direction of the processing tray to the direction of the sheet conveying path inside the sheet processing apparatus, and stores the heat by heat dissipation from the sheet when conveying a high-temperature sheet. The inside of the processing apparatus can be cooled. Further, it is possible to cool an area from the sheet discharge unit 208 of the copying machine main body to the vicinity of the fixing unit 207.

  As described above, the sheet processing apparatus cools the inside of the sheet processing apparatus in advance by the above-described operation, thereby minimizing the temperature rise of the sheets continuously fed onto the processing tray inside the sheet processing apparatus in the next job setting. Can be suppressed. In addition, the sheet processing apparatus can prevent sheets from sticking (sheet ejection adhesion) when aligning the sheets on the processing tray with an offset roller, and ensures sheet alignment processing while maintaining high-quality images. Can be done.

  Since the copying machine A includes the sheet processing apparatus 400 that prevents the sheets from adhering to each other, it is possible to reduce image formation of the adhering sheets again and increase the image forming efficiency.

1 is a cross-sectional view taken along a sheet conveyance direction of a copying machine including a sheet processing apparatus according to an embodiment of the present invention. It is sectional drawing which looked at the principal part of the sheet processing apparatus from the front side. FIG. 3 is a plan view of FIG. 2. FIG. 10 is a diagram for explaining an operation of supplying a sheet to a processing tray. It is a figure for operation | movement description which abuts a sheet | seat on a rear-end alignment member and aligns. It is a figure for operation | movement explanation which cools a sheet | seat with a downstream air duct. It is a top view of the conveyance guide of FIG. It is a figure for operation | movement description which cools the inside of a sheet processing apparatus with an upstream air duct. It is AA arrow sectional drawing of the conveyance guide of FIG. It is a control block diagram.

Explanation of symbols

A Image forming device (copier)
B An arrow indicating the sheet conveyance direction S Sheet Sa Rear end of sheet Sb Side edge of sheet 100 CPU of copying machine
101 CPU of sheet processing apparatus
200 Printer unit (image forming means)
207 Fixing device 208 Sheet discharge unit 300 Automatic document feeder (ADF)
400 Sheet processing device 406 Offset roller holder 407 Offset roller (sheet conveying means)
410 processing tray (sheet stacking means)
411 Rear end alignment member (upstream end alignment member)
411a Discharge port 412 Gripper 413 Sheet bundle discharge member 415 Sheet bundle discharge sensor (detection means)
416 Side end alignment member 420 Stapler unit 421 Stack tray 500 Main body 601 Cooling fan 601a Cooling air 601b Cooling air 601c Suction air 602 Conveying guide (guide member)
603 Air duct 603a Downstream air duct (first air duct)
603b Upstream air duct (second air duct)
604 Air path change plate (air path switching member)
604a Rotating shaft 604b Position 604c where the air passage changing plate forms the downstream air duct 604c Position 610 where the air passage changing plate forms the upstream air duct Seat cooling device (cooling means)

Claims (6)

A sheet stacking unit on which a sheet on which a toner image is heated and fixed is stacked;
Sheet conveying means for pressing the sheets stacked on the sheet stacking means against the sheet stacking means and moving them upstream in the sheet conveying direction;
An upstream end alignment member that receives the upstream end of the sheet moved to the upstream side by the sheet conveying means and aligns the upstream end, and
In a sheet processing apparatus in which a sheet stacked on the sheet stacking unit passes over the upstream end alignment member,
A cooling means for cooling the sheet by sending air between the lower surface of the sheet passing over the upstream end alignment member and the sheet stacking means;
A sheet processing apparatus. The upstream end alignment member includes the air discharge port.
The sheet processing apparatus according to claim 1. The cooling unit includes a first air duct that guides air to the sheet stacking unit, a second air duct that guides air upstream from the sheet stacking unit in the sheet conveying direction, and the first air. An air path switching member that selectively guides air to the duct and the second air duct;
The sheet processing apparatus according to claim 1, wherein the sheet processing apparatus is a sheet processing apparatus. A detecting means for detecting that a sheet is stacked on the sheet stacking means;
The air path switching member selects the first air duct when the detection means detects a sheet,
The sheet processing apparatus according to claim 3. A guide member for guiding a sheet to the sheet stacking means;
The upstream end alignment member is provided on the downstream side of the guide member, and the discharge port of the second air duct is provided on the upstream side of the guide member.
The sheet processing apparatus according to claim 1, wherein the sheet processing apparatus is a sheet processing apparatus. Image forming means for forming an image on a sheet;
A sheet processing apparatus for processing a sheet on which an image is formed by the image forming unit,
The image forming apparatus, wherein the sheet processing apparatus is the sheet processing apparatus according to claim 1.

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