JP2010089969A - Sheet processing apparatus and image forming apparatus provided with the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To practically prevent the opening of an opening end of a folded sheet or a sheet bundle, and to improve the consistency of sheets. <P>SOLUTION: The sheet processing apparatus 1 is equipped with a curling roller pair curling an end of a sheet, a return paddle and a rear end stopper 62 abutting on one end of the sheet in a conveying direction and carrying out alignment in the conveying direction, and a folding device 71 folding the sheet or the sheet bundle curled by the return paddle and the rear end stopper. One end is not curled and the other end is curled to a predetermined length by the curling roller pair, and after aligning the uncurled one-side ends by the return paddle and the rear end stopper, the sheet or the sheet bundle is folded by a folding means so that a recessed face side of the curled other end faces a side of the one end. The folded sheet or the sheet bundle is hardly opened at the opening end, and consistency is improved. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a sheet processing apparatus that folds a sheet bundle and an image forming apparatus that includes the sheet processing apparatus in an apparatus main body.

  Conventionally, for example, there is a sheet processing apparatus that binds sheets in a bundle. This sheet processing apparatus is configured to perform processing (so-called booklet (saddle stitching) creation, saddle stitch processing) in which a sheet is bundled and a middle portion is stapled and then folded into a booklet. Such a sheet processing apparatus may be provided in the main body of the image forming apparatus as one of the components of the image forming apparatus (see Patent Document 1).

  An image forming apparatus provided with the sheet processing apparatus is shown in FIG. A conventional sheet processing apparatus 901 shown in FIG. 14 includes the saddle stitch processing, alignment processing for aligning the end portions of the sheet bundle (so-called sort processing), and side-stitch binding processing (so-called staple processing) for binding the end portions of the sheet bundle. Sort processing) can be performed.

  The conventional sheet processing apparatus 901 performs saddle stitch processing as follows. The sheet processing apparatus 901 stacks sheets sequentially received from the apparatus main body 903 of the image forming apparatus 902 on a saddle stitch processing tray 910 formed in a substantially straight shape with a steep inclination, and receives the sheets with a stopper 911 to form a bundle. A width aligning device (not shown) performs the width alignment of the sheet P. Thereafter, the intermediate stapler unit 912 binds two locations near the approximate center of the sheet bundle. The stopper 911 moves up and down to oppose the bound portion of the bound sheet bundle to the nip of the pair of folding rollers 914 and the thrust plate 913. The pushing plate 913 feeds the sheet bundle into the nip of the pair of folding rollers 914 while protruding the binding portion of the sheet bundle. The pair of folding rollers 914 folds the sheet bundle into two while conveying the sheet with pressure. Finally, the discharge roller pair 915 discharges the sheet bundle to the sheet stacking unit 905. As described above, the conventional sheet processing apparatus 901 can form a sheet bundle into a two-fold booklet.

  Further, the sheet processing apparatus 901 performs the staple sort process as follows. The sheet processing apparatus 901 aligns the width of the sheet by the width aligner 907 while sequentially receiving the sheets P on which the image is formed on one side or both sides in the apparatus main body 903 of the image forming apparatus 902 by the intermediate tray 906 (width alignment). Bundling). Thereafter, the end stapler unit 908 binds the end of the sheet bundle. Finally, the discharge roller pair 909 discharges to the sheet stacking unit 904.

JP 2000-153947 A

  However, in the conventional sheet processing apparatus, when the booklet is created, if the folding pressure is weak or the sheet is made of a material that is difficult to bend, the opening end of the folded booklet sheet bundle is slightly opened, The quality could be degraded. Further, when the opening end of the sheet bundle is opened as described above, the sheet bundle that is subsequently discharged may enter the opening end of the preceding sheet bundle, and the sheet bundle may not be sequentially and reliably stacked.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a sheet processing apparatus in which the open end of a folded sheet bundle is hardly opened.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an image forming apparatus having a sheet processing apparatus that prevents an open end of a folded sheet bundle from being almost opened, thereby improving image forming efficiency.

  In order to achieve the above object, a sheet processing apparatus according to the present invention includes a curling unit that curls an end portion of a sheet, an alignment unit that abuts one end of the sheet in the conveyance direction and aligns the conveyance direction, Folding means for folding the sheet or sheet bundle curled by the curling means, and the curling means causes the other end to be curled to a predetermined length without curling the one end. After aligning the one end portion that is not curled by the aligning means, the sheet or the sheet bundle is folded by the folding means so that the concave surface side of the other curled end portion faces the one end portion side. It has become.

  In order to achieve the above object, an image forming apparatus according to the present invention includes an image forming unit that forms an image on a sheet and the sheet processing apparatus described above, and the sheet processing apparatus performs image processing by the image forming unit. The sheet formed is processed.

  In the sheet processing apparatus of the present invention, the folding means folds the sheet bundle so that the end of the sheet curled by the curling means faces inward, so the folded sheet or the open end of the sheet bundle Becomes difficult to open, and the quality of the sheet or sheet bundle can be improved.

  In the sheet processing apparatus of the present invention, since the trailing edge aligning means aligns the trailing edge of the sheet, the sheet bundle can be bound and folded with the edges of the sheet bundle aligned, and the folded sheet bundle can be folded. The appearance can be improved.

  In the image forming apparatus of the present invention, the opening end of the preceding sheet bundle is difficult to open even if the sheet processing apparatus continuously discharges the sheet bundle, so that the succeeding sheet bundle enters the opening end of the preceding sheet bundle. Therefore, the image can be formed continuously on the sheet, and the image forming efficiency can be improved.

1 is a schematic front sectional view of a color copying machine as an image forming apparatus according to an embodiment of the present invention. 1 is a schematic front sectional view of a sheet processing apparatus according to an embodiment of the present invention. FIG. 3 is an enlarged view of a curling roller pair in the sheet processing apparatus in FIG. 2. FIG. 6 is a diagram illustrating a state in which a sheet is sent from the apparatus main body of the color copying machine in booklet mode (saddle stitch bookbinding processing). FIG. 5 is a diagram illustrating a state in which sheets are stacked on a processing tray following FIG. 4. FIG. 6 is a view in which the sheet is in contact with the rear end stopper following FIG. 5. FIG. 7 is a diagram subsequent to FIG. 6, where the sheet bundle is bound and then conveyed to a curved path. FIG. 8 is a diagram when the sheet bundle is folded following FIG. 7. FIG. 9 is a diagram in which a sheet bundle is discharged following FIG. 8. FIG. 6 is a diagram illustrating a state in which a sheet is fed from the main body of the color copying machine in a side binding mode (staple sorting process). FIG. 11 is a view of the sheet bundle bound after the sheet comes into contact with the trailing end stopper following FIG. 10. FIG. 12 is a diagram illustrating a state in which the sheet bundle starts to be discharged following FIG. 11. FIG. 13 is a diagram in which a sheet bundle is discharged following FIG. 12. It is a schematic front sectional view of a conventional image forming apparatus.

  Hereinafter, an image forming apparatus and a sheet processing apparatus according to an embodiment of the present invention will be described with reference to the drawings.

(Image forming device)
A color copying machine as an image forming apparatus will be described with reference to FIG. Examples of the image forming apparatus include a copying machine, a printing machine, a laser beam printer, and a complex machine of these. The image forming apparatus according to the embodiment of the present invention is a multicolor copying machine, but is not limited thereto.

  The color copying machine 30 includes, from the bottom, an apparatus main body 31, a sheet processing apparatus 1, an image reading device 36 as an image reading unit, and a document supply device 35 in that order. The color copying machine 30 is a so-called in-body discharge type because the sheet is discharged to the sheet processing apparatus 1 between the apparatus main body 31 and the image reading apparatus 36. The sheet processing apparatus 1 may be detachable.

  The document supply device 35 automatically supplies a document to the image reading device 36. The image reading device 36 as reading means reads a document supplied by the document supply device 35 or a document placed on the glass table 42 by the user by opening the document supply device 35 rearward. The document supply device 35 and the image reading device 36 are not necessarily provided. Even if the image reading device 36 is provided, the document supply device 35 is not necessarily provided.

  The operation of the color copying machine 30 will be described. The document supply device 35 automatically sends the document to the reading position of the image reading device 36. The image reading device 36 reads an image of a document. A controller (not shown) sends a signal to the laser scanner unit 2 based on the image information read by the image reading device 36. The laser scanner unit 2 irradiates a photosensitive drum 3 as an image forming unit whose surface is uniformly charged with laser light. Note that the image information signal received by the laser scanner unit 2 may be an image information signal sent from an external personal computer or the like. Further, when the image reading device 36 is not provided, the laser scanner unit 2 irradiates the photosensitive drum 3 with laser light based on an image signal sent from the outside.

  The electrostatic latent image on the photosensitive drum 3 is developed with toner by the developing device 5 to become a toner image. The toner image is transferred to the transfer belt 21 and then transferred to a sheet P such as paper or an OHP sheet.

  On the other hand, the sheet P is selectively and appropriately fed from the sheet cassettes 32 and 33 by the pickup roller 38, separated one by one by the separation roller pair 37, and fed to the registration roller pair 39. Then, after the skew is corrected by the registration roller pair 39, the sheet P is fed to the transfer position in synchronization with the rotation of the photosensitive drum 3 and the transfer belt 21. As a result, the toner image on the transfer belt 21 is transferred to the sheet P.

  Thereafter, the sheet P is guided to the fixing roller pair 6 and heated and pressed by the fixing roller pair 6 to permanently fix the toner image. The fixing roller pair 6 is in contact with the fixing upper separation claw and the fixing lower separation claw, and the sheet P is separated from the fixing roller pair 6 by these claw. The separated sheet P is sent from the apparatus main body 31 of the color copying machine to the sheet processing apparatus 1 by the first discharge roller pair 7.

  If the double-sided printing is set, the separated sheet P is guided to the conveyance path 13 by the direction switching flapper 9 and discharged to the outside of the apparatus main body 31 by the second discharge roller pair 8. When the rear end portion of the sheet P passes through the direction switching flapper 9, the second discharge roller pair 8 is reversed, and the sheet P is guided to the conveyance path 14 by the direction switching flapper 9. As a result, the sheet P is turned upside down and sent again to the transfer belt 21 to transfer the toner image to the back side. Thereafter, the sheet P is heated and pressed by the fixing roller pair 6 to fix the toner image, and is sent from the apparatus main body 31 to the sheet processing apparatus 1 by the first discharge roller pair 7 through the conveyance path 16.

(Sheet processing equipment)
The sheet processing apparatus will be described with reference to FIGS. The sheet processing apparatus of this embodiment is incorporated in a color copying machine, but may be incorporated in a printing machine, a laser beam printer, or the like. Therefore, the sheet processing apparatus of this embodiment is not incorporated only in a color copying machine.

(Description of configuration of sheet processing apparatus)
The sheet processing apparatus 1 includes a curling roller pair 100 as a curling device that curls the leading edge of the sheet in the thickness direction of the sheet, and a folding device that folds the sheet curled by the curling roller pair 100 or a sheet bundle. 9, and the folding device 71 folds the sheet or the sheet bundle so that the end portion Pa of the sheet P curled by the curling roller pair 100 faces inward as shown in FIG. 9. ing.

  The sheet processing apparatus 1 binds sheets fed from the apparatus main body 31 of the color copying machine 30 into a bundle and binds the center of the sheet bundle and the vicinity of the center with an intermediate stapler (saddle stitch stapler) 11 as a binding means. Saddle-stitch bookbinding processing (saddle stitch processing, booklet mode processing) in which the sheet bundle is folded in half with a folding device 71 as a folding means, and the edge binding of the sheet bundle with the end stapler 10 is performed. Processing (staple sort processing, flat binding mode), alignment processing (sort processing) is performed simply by aligning the sheet bundle without binding the sheet bundle. The sheet processing apparatus 1 may be configured to perform at least only saddle stitch processing.

  The conveyance path 19 is configured to receive a sheet from the first discharge roller pair 7. A pair of discharge rollers 18 as a sheet conveying unit discharges a sheet from a conveyance path 19 to a processing tray 40 as a stacking unit.

  A curling roller pair 100 is provided upstream of the discharge roller pair 18 in the transport path 19. As shown in FIG. 3, the curling roller pair 100 includes a nip roller 101 made of a low-hardness elastic member (urethane foam roller) rotated by a nip roller rotation motor M1, and a high hardness (rotated following contact with the nip roller 101). Metal) pressure roller 102. The pressure roller 102 is moved toward and away from the nip roller 101 by a pressure roller moving motor M8, moving between a solid pressure position and a retracted position indicated by a broken line. The pressure roller 102 is in contact with the nip roller 101 by crushing the nip roller 101 to some extent. For this reason, the sheet that has passed through the pair of curling rollers 100 in which the pressure roller 102 is in pressure contact with the nip roller 101 is imparted with a curl (upward curl) in the same direction (upward) as the nip shape. The curl direction is the same as the bending direction of the bending path 46 described later. The pressure applied by the pressure roller 102 is set so that all the conveyed sheets are curled with a curvature larger than the curvature of the curved path 46 at a minimum. Note that the trailing edge of the sheet conveyance direction is not curled by the curling roller pair 100 and remains straight.

  The discharge roller pair 18 includes a drive roller 18a and a driven roller 18b that rotates in contact with the drive roller 18a. The drive roller 18a is rotated by a nip roller rotation motor M1. A return belt 60 is sandwiched between the nips of the discharge roller pair 18. The return belt 60 is also driven to rotate counterclockwise by the drive roller 18a. A sheet discharge sensor 20 as a sheet detection unit is disposed near the upstream side of the curling roller pair 100. The paper discharge sensor 20 detects a sheet passing through the conveyance path 19 and drives the pressure roller moving motor M8 based on the detection result by the paper discharge sensor 20 so that the pressure roller 102 becomes the nip roller 101. It is controlled by the control part mentioned later so that it may contact / separate with respect to.

  The processing tray 40 is formed in a planar shape and is disposed horizontally. At one end portion of the processing tray 40, a trailing end stopper 62 serving as a reference for the upstream end portion (the right end portion and the trailing end portion in FIG. 2) of the sheet on the processing tray 40 in the conveyance direction is on standby.

  Accordingly, the sheets stacked on the processing tray 40 receive the return force of the return belt 60, and the rear ends thereof are abutted against the rear end stopper 62 so that the rear ends are aligned. A rear end stopper 62 as a sheet bundle conveying unit is provided on the belt 63. The belt 63 is circulated by a belt motor M2. As shown in FIG. 2, the rear end stopper 62 has the right end portion of the return belt 60 as a home position.

  The end stapler 10 is disposed in the vicinity of the home position of the rear end stopper 62. The end stapler 10 staples the trailing end of the sheet bundle in the “flat stitching mode”.

  The alignment plate pair 41 aligns (width aligns) the end portions of the sheet bundle on the processing tray 40 along the sheet conveyance direction. The alignment plate pair 41 is moved in the sheet width direction by a rack gear and a pinion gear (not shown) and a pinion motor M3 that rotates the pinion gear. The return paddle 50 rotates around the support shaft 51 in the direction of the arrow (counterclockwise), and feeds the sheet discharged from the discharge roller pair 18 toward the rear end stopper 62. The return paddle 50 has a surface formed of an elastic member having a low friction coefficient, and rotates while sliding on the sheet after abutting the sheet against the rear end stopper 62. Further, the stop position of the return paddle 50 is retracted above an upper guide 52 to be described later (the position indicated by a solid line in FIG. 2) so as not to interfere with the conveyance of the sheet. The return paddle 50 is rotated by a paddle motor M4.

  Two intermediate staplers 11 are arranged in the sheet width direction on the downstream side of the return paddle 50. The intermediate stapler 11 includes an anvil 12 and a driver 15. The upper guide 52 is configured to guide the sheet between the anvil 12 and the driver 15 with the processing tray 40. The sheet receiving portion of the upper guide 52 is inclined in a trumpet shape, and the vicinity of the intermediate stapler 11 is a plane parallel to the processing tray 40 arranged horizontally. The intermediate stapler 11 staples the intermediate portion of the sheet bundle in the “booklet mode”.

  A curved path 46 serving as a curved guide path and a horizontal path 49 serving as a straight guide path are disposed on the downstream side of the intermediate stapler 11. The curved path 46 and the horizontal path 49 are selected by a flapper 80. The flapper 80 selectively tilts the paths 46 and 49 by the solenoid SL1. The curved path 46 is curved by being branched upward from the horizontal path 49 with the branching portion 46 a as a boundary, and is constituted by an inner guide 45 and an outer guide 44. The horizontal path 49 extends linearly from the processing tray 40 and includes an upper guide 48 and a lower guide 47. The distance between the fixing roller pair 6 of the apparatus main body 31 of the color copying machine 30 shown in FIG. 1 and the branching portion 46a shown in FIG. 2 is set to be longer than the longest sheet processed by this apparatus. A conveyance roller (including the first discharge roller pair 7) on the downstream side of the fixing roller pair 6 conveys the sheet at a speed synchronized with the discharge roller pair 18.

  A paddle 90 is disposed in the curved path 46 on the downstream side of the branch portion 46a. Similar to the return paddle 50, the paddle 90 is made of an elastic member having a low friction coefficient, and the conveying force is set lower than that of the discharge roller pair 18. The paddle 90 receives the rotational force of the paddle motor M7 and rotates in the arrow direction (clockwise). The curved paddle 90 is normally retracted to the inner side of the inner guide 45 so as not to obstruct the sheet moving in the curved path 46.

  A veneer 72 is disposed inside the curve of the curve path 46. The veneer 72 is reciprocated in the direction of the arrow (solid line, broken line) by a veneer drive motor M5 and a transmission mechanism (not shown) (not shown). The standby position (solid line position) is inside the curve of the curve path 46. The butt position (broken line position) is a position that penetrates the curved path 46. A through-hole is formed at a position corresponding to the thrust plate 72 of the inner guide 45 and the outer guide 44 so as not to hinder the movement of the thrust plate 72.

  The pair of folding rollers 73 is arranged so that the nip faces the veneer 72, and when the sheet in the curved path 46 is struck by the veneer 72, it rotates in the direction of the arrow to divide the sheet into two. It is supposed to be folded. The folded sheets are stacked on the stack tray 4 via the booklet discharge roller pair 74. The folding roller 73 and the saddle booklet discharge roller pair 74 are rotated by a folding motor M6. The thrust plate 72, the folding roller pair 73, the thrust plate drive motor M5, the folding motor M6, and the like constitute a folding device 71.

  A bundle discharge roller pair 75 that discharges the sheets in the horizontal path 49 to the stack tray 4 is provided at the downstream end of the horizontal path 49. The bundle discharge roller pair 75 is rotated by a nip roller rotation motor M1. The motors M1 to M8, the solenoid SL1, the paper discharge sensor 20, and the like described above are connected to a CPU 79 as a control unit. The CPU 79 conveys the sheet, contacts and separates the pressure roller 102 from the nip roller 101, and folds. Processing and the like are controlled. In the present embodiment, the configuration in which the CPU 79 is provided in the sheet processing apparatus 1 is described. However, the sheet processing apparatus 1 is controlled by the control unit on the color copying machine 30 side as an image forming apparatus. Also good.

(Explanation of operations in “Booklet mode (saddle stitching)”)
When the booklet mode is designated, the pressure roller 102 of the curling roller pair 100 moves to the pressure position as shown in FIG. That is, the pressure roller 102 is pressed against the nip roller 101 by the nip roller rotation motor M1. Then, the flapper 80 is moved to the illustrated position by the solenoid SL1, and the curved path 46 is selected.

  The sheet P discharged from the apparatus main body 31 of the color copying machine 30 is detected by the discharge sensor 20 at the leading edge, and is fed with an upper curl by the curling roller pair 100 based on the detection result. When the feeding length of the conveyed sheet is L1, and the distance between the discharge roller pair 18 and the branching portion 46a is L2, the sheet is conveyed by the curling roller pair 100 by the length of (L1-L2). Then, the pressure roller 102 moves to the retracted position. In this way, when the sheet is discharged to the processing tray 40, a curl in the same direction as the curved path 46 by the length of (L1-L2) at the leading end portion of the sheet that enters the curved path 46 after the branching portion 46a. Is granted. As shown in FIG. 5, after that, the sheet is continuously conveyed by the discharge roller pair 18 and discharged to the processing tray 40. Since the sheet is appropriately curled with the leading edge facing upward, the sheet smoothly slides on the processing tray 40 and is discharged to the processing tray 40. At that time, the leading edge of the sheet enters the curved path 46. However, since the curl is imparted to the leading edge of the sheet, the load is reduced and the sheet is conveyed and discharged stably with almost no resistance from the curved path 46.

  The feeding length L1 of the conveyed sheet differs depending on the conveyed sheet size. In contrast, the distance L2 between the discharge roller pair 18 and the branching portion 46a as the starting point of the curved path 46 is determined. Therefore, the curling length, that is, the length (L1-L2) that enters the curved path 46 varies depending on the length size of the sheet. The length (L1-L2) is determined by the timing at which the pressure roller 102 is retracted. As described above, since the curling length can be changed depending on the length size of the sheet, the sheet processing apparatus 1 according to the present embodiment can stably carry and discharge the sheet regardless of the length size of the sheet. Can do.

The curl may be formed only on thick paper (basis weight of about 105 g / m ^{2 to} about 250 g / m ² ) that is difficult to bend the curved path 46 and receives resistance by the curved path 46. Thus, by limiting the range of the sheet basis weight, the accuracy of the curl amount imparted to the sheet can be increased. When sending plain paper (basis weight: about 64 g / m ^{2 to} about 90 g / m ² ) while feeding thick paper, the pressure roller 102 is retracted, and the sheet is discharged from the conveyance path 19 to the discharge roller pair 18. Only transported and discharged. Although the setting of the sheet basis weight is input from the operation unit of the color copier 30 (not shown), sheet thickness detection means may be provided in the sheet conveyance path and controlled based on the detection result.

  As shown in FIG. 6, the sheet discharged to the processing tray 40 starts to move in the direction of the arrow along with the rotation of the return paddle 50 that has been stopped, receives the conveying force of the return belt 60, and is not curled. The rear end is abutted against the rear end stopper 62 and the rear end is aligned. The return paddle 50, the rear end stopper 62, etc. constitute rear end alignment means. Subsequently, sheet width alignment is also performed by the sandwiching operation of the alignment plate pair 41. At this time, since the curling is applied to the sheet only at the leading end portion entering the curved path 46, the return to the trailing end stopper 62, which tends to occur when the trailing end portion is curled, Problems such as buckling during abutment do not occur.

  The above operation is repeated until a predetermined number of sheets are stacked on the processing tray 40.

  Next, as shown in FIG. 7, the trailing edge stopper 62 moves in the direction of the arrow, and the sheet bundle is arranged such that the center in the conveyance direction of the sheet bundle stacked on the processing tray 40 faces the binding position of the intermediate stapler 11. Transport. The intermediate stapler 11 staples the sheet bundle. During this time, the trailing edge stopper 62 is stopped and holds the trailing edge of the sheet bundle. The binding position of the sheet bundle is generally the center in the sheet bundle length direction, but is not necessarily the center. The portion indicated by the symbol M is a bound portion.

  Then, the trailing edge stopper 62 moves again downstream in the sheet conveyance direction, conveys the sheet bundle so that the center of the sheet bundle conveyance direction reaches the nip of the folding roller 73, and stops. Thereafter, as shown in FIG. 8, the waiting veneer 72 starts an operation of poking the sheet bundle. Also during this time, the trailing edge stopper 62 stops and holds the trailing edge of the sheet bundle. As the pushing plate 72 starts to move, the folding roller pair 73 also starts to rotate. The center of the bundle in the conveying direction, that is, the binding position is pushed into the nip of the folding roller pair 73 by the movement of the pushing plate 72. Then, the sheet bundle is conveyed to the folding roller pair 73 and the booklet discharge roller pair 74 while being folded in half, and stacked on the stack tray 4 as shown in FIG.

  Since the curling direction of the leading edge of the sheet and the bending direction of the curved path 46 are upward, and the folding device 71 folds the sheet bundle so that the curled portion of the leading edge of the sheet faces inward, the folding process stacked on the stack tray 4 In the finished sheet bundle, the end portion Pa curled by the curling roller 100 faces inward. Moreover, the sheet bundle is formed in a booklet shape and is stacked on the processing tray 40 with the surface having the curled end portion Pa on the upper side and the non-curled surface on the lower side. The end of the tray 4 is difficult to open.

  Therefore, the quality of the sheet bundle can be improved. Further, when the succeeding sheet bundle is discharged from the booklet discharge roller pair 74, it does not get caught on the end of the preceding sheet bundle or enter the preceding sheet bundle. Easily loaded. Further, since the end portion of the sheet bundle in the form of a booklet is difficult to open, the thickness of the sheet bundle is thinner than that of the uncurled sheet bundle indicated by a broken line in FIG. For this reason, more curled sheet bundles can be stacked on the stack tray 4 than the uncurled sheet bundle.

  In the sheet processing apparatus 1 of the present embodiment, the bending direction of the bending path 46 is upward, but may be downward. In this case, the leading edge of the sheet needs to be curled downward, and when the sheet bundle is stacked on the stack tray 4, the curled portion is on the lower side. However, the end of the sheet bundle is difficult to open, the subsequent sheet bundle is easily stacked on the preceding sheet bundle, and the thickness of the sheet bundle is reduced. There is no.

  Further, in the sheet processing apparatus 1 according to the present embodiment, when the curvature radius of the curved path 46 is large or depending on the strength of the waist of the sheet, the sheet bundle is formed by curling the sheet bundle without curling the front end of the sheet. In some cases, it can be smoothly conveyed. In such a case, the sheet is curled so as not to open the sheet bundle, and either one or both of the leading end and the trailing end of the sheet may be curled. That is, at least one of the leading edge and the trailing edge of the sheet may be curled. The sheet bundle is bound at the center by the intermediate stapler 11, but the binding position is not limited to the center. Further, it may be folded into the folding device 71 and discharged to the stack tray 4 without being bound. It goes without saying that the effect of the present invention can be obtained even if the number of sheets to be processed is one.

  Furthermore, since the sheet processing apparatus 1 of the present embodiment includes the folding device 71 in the vertical region of the curved path 46, the sheet processing device 1 is formed in a small size.

(Explanation of operations in “Side binding mode (staple sort processing)”)
When the side stitching mode is designated, as shown in FIG. 10, the pressure roller 102 of the curling roller pair 100 moves to the retracted position, and the flapper 80 moves away from the processing tray 40 and selects the horizontal path 49. The sheet P discharged from the apparatus main body 31 of the color copying machine 30 (see FIG. 1) is detected by the sensor 20, passes through the conveyance path 19, is conveyed only to the discharge roller pair 18, and is transferred to the processing tray 40. Discharged. As shown in FIG. 11, the sheet P discharged to the processing tray 40 starts to move in the direction of the arrow in accordance with the rotation of the return paddle 50 that has been stopped, and then receives the conveying force of the return belt 60. It is abutted against the end stopper 62. As a result, the trailing edges of the sheets are aligned. Subsequently, the alignment plate pair 41 sandwiches the sheet and performs width alignment.

  The above operation is repeated until a predetermined number of sheets are stacked on the processing tray 40.

  The aligned sheet bundle is stapled at the end by the end stapler 10. Thereafter, as shown in FIG. 12, the sheet bundle is transferred in the direction of the arrow by the rear end stopper 62. Then, as shown in FIG. 13, the sheet bundle is transferred to the bundle discharge roller pair 75 rotated by the nip roller rotation motor M <b> 1 together with the discharge roller pair 18 and stacked on the stack tray 4. In this way, a booklet in which the end of the sheet bundle is stapled is formed.

  The alignment process (sort process) is a process in which the end operation of the sheet bundle is not performed by the end stapler 10 in the staple sort process.

P sheet Pa edge M binding part 1 sheet processing apparatus 3 photosensitive drum (image forming means)
10 End stapler 11 Intermediate stapler (binding means)
18 Discharge roller pair (sheet conveying means)
18a driving roller 18b driven roller 20 paper discharge sensor (sheet detecting means)
30 Color copier (image forming device)
31 Color copying machine (image forming apparatus) main body 35 Document supply device 36 Image reading device (image reading means)
40 Processing tray (sheet stacking means)
46 Curved path (curved guideway)
46a Branch 49 Horizontal path (straight guideway)
50 Return paddle (rear end alignment means)
62 Rear end stopper (sheet bundle conveying means, rear end aligning means)
71 Folding device (folding means)
79 CPU (control unit)
100 Curling roller pair (curling device)
101 Nip roller 102 Pressure roller

Claims (4)

Curling means for curling the edge of the sheet;
An alignment means for aligning the conveyance direction by abutting one end of the sheet in the conveyance direction;
Folding means for folding the sheet or sheet bundle curled by the curling means,
The curling means does not curl the one end, curls the other end to a predetermined length, aligns the one end that is not curled by the aligning means, and then curls the end. Fold the sheet or sheet bundle by the folding means so that the concave surface side of the other end is directed to the one end.
A sheet processing apparatus. The alignment means includes a stopper, moves the sheet on a flat surface, and aligns the one end by abutting the one end against the stopper.
The sheet processing apparatus according to claim 1. A binding means for binding an intermediate portion in the conveyance direction of the sheet bundle;
After the one end is aligned by the alignment means, the sheet bundle is bound by the binding means, and the portion of the sheet bundle bound by the binding means is folded by the folding means.
The sheet processing apparatus according to claim 2. Image forming means for forming an image on a sheet;
A sheet processing apparatus according to any one of claims 1 to 3,
The sheet processing apparatus performs processing on a sheet on which an image is formed by the image forming unit.
An image forming apparatus.

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