Sheet processing device

Abstract

The objective is to provide a sheet processing device that can suppress a decline in processing quality. [Solution] The sheet processing apparatus of the embodiment includes a first roller, a second roller, and a cover. The first roller is rotatable around a first rotation axis. The second roller is rotatable around a second rotation axis which is above the first rotation axis and on the first horizontal side of the first rotation axis. The second roller can contact the first roller to form a nip, and can transport a saddle-folded booklet diagonally downward by gripping the booklet in the nip and rotating it. In a cross section perpendicular to the second rotation axis, a straight line including the contact line of the nip is defined as the first straight line, and a straight line parallel to the first straight line and passing through the second rotation axis is defined as the second straight line. The cover covers the outer circumference of the second roller on the first horizontal side of the second roller, and its lower end is positioned between the first and second straight lines.

Description

Technical Field

[0001] Embodiments of the present invention relate to a sheet processing apparatus.

Background Art

[0002] A sheet processing apparatus having a saddle folding unit is used. The saddle folding unit folds a sheet to form a booklet. The formed booklet is discharged from a pair of rollers of a discharge mechanism to a booklet tray. Booklets are stacked and arranged in the booklet tray. There is a need for a sheet processing apparatus that can suppress a decrease in processing quality.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The problem to be solved by the present invention is to provide a sheet processing apparatus that can suppress a decrease in processing quality.

Means for Solving the Problems

[0005] The sheet processing apparatus of embodiment 1 comprises a first roller, a second roller, and a cover. The first roller is rotatable around a first rotation axis. The second roller is rotatable around a second rotation axis located above the first rotation axis and on the first horizontal side of the first rotation axis. The second roller can contact the first roller to form a nip, and can transport a saddle-folded booklet diagonally downward by gripping the nip and rotating it. In a cross section perpendicular to the second rotation axis, a straight line containing the contact line of the nip is defined as the first straight line, and a straight line parallel to the first straight line and passing through the second rotation axis is defined as the second straight line. The cover covers the outer circumference of the second roller on the first horizontal side of the second roller, and its lower end is positioned between the first and second straight lines.

[0006] The sheet processing apparatus of Embodiment 2 is based on the sheet processing apparatus described in Embodiment 1. In a cross-section perpendicular to the second rotation axis, the third straight line is defined as a straight line parallel to the first straight line and tangent to the outer circumference of the second roller above the second rotation axis. The upper end of the cover is positioned above the third straight line.

[0007] The sheet processing apparatus of embodiment 3 is based on the sheet processing apparatus described in embodiment 1 or 2. The cover extends over the entire axial range of the second roller.

[0008] The sheet processing apparatus of embodiment 4 is based on the sheet processing apparatus described in any one of embodiments 1 to 3. Of the first roller and the second roller, one is a drive roller and the other is a driven roller. The sheet processing apparatus further comprises a control unit and a damming member. The control unit controls the rotation of the drive roller. The leading edge of a booklet discharged from the nip can come into contact with the damming member. The control unit continues to rotate the drive roller after at least an A5-sized booklet has been discharged from the nip until the leading edge of the booklet comes into contact with the damming member.

[0009] The sheet processing apparatus of embodiment 5 is based on the sheet processing apparatus described in any one of embodiments 1 to 4. The direction in which the first rotation axis and the second rotation axis are aligned is defined as the first direction. The cover is movable in the first direction together with the second roller. [Brief explanation of the drawing]

[0010] [Figure 1] A schematic diagram of an image forming apparatus including a sheet processing apparatus according to an embodiment. [Figure 2] A block diagram showing an example of the functional configuration of an image forming apparatus. [Figure 3] Front cross-sectional view of the booklet ejection section. [Figure 4] Enlarged view of the area surrounding the discharge mechanism in Figure 3. [Figure 5] Enlarged view of the area around the discharge mechanism in a modified embodiment. [Figure 6] A diagram illustrating the operation of the discharge mechanism in the embodiment. [Figure 7] A diagram illustrating the operation of a conventional discharge mechanism. [Modes for carrying out the invention]

[0011] The sheet processing apparatus of this embodiment will be described below with reference to the drawings. Figure 1 is a schematic diagram of an image forming apparatus 1 including a sheet processing apparatus 200 according to an embodiment. The image forming apparatus 1 comprises an image forming apparatus body 100 and a sheet processing apparatus 200. The image forming apparatus body 100 and the sheet processing apparatus 200 are arranged adjacent to each other.

[0012] The main body 100 of the image forming apparatus will now be described. The image forming apparatus main unit 100 forms an image on a sheet (recording medium) using a recording material. For example, the sheet is plain paper or label paper. A specific example of a recording material is toner. The toner is either a toner used as a decolorizing recording material or a toner used as a non-decolorizing recording material.

[0013] For example, the image forming apparatus main unit 100 is a multifunction device. As shown in Figure 1, the image forming apparatus main unit 100 includes a display unit 15, an operation unit 14, an image reading unit 16, a printer unit 17, a sheet storage unit 18, a paper discharge roller 19, and a first control unit 90.

[0014] The display unit 15 is an image display device such as a liquid crystal display or an organic EL (Electro-Luminescence) display. The display unit 15 displays various information related to the image forming apparatus main body 100 and the sheet processing apparatus 200. The operation unit 14 has multiple buttons. The operation unit 14 receives user input. The operation unit 14 outputs a signal corresponding to the user's input to the first control unit 90 of the image forming apparatus body 100. The display unit 15 and the operation unit 14 may be configured as an integrated touch panel.

[0015] The image reading unit 16 reads the image information to be read as brightness and darkness. The image reading unit 16 outputs the read image information to the printer unit 17. The sheet storage section 18 stores the sheets used for image formation. The sheet storage section 18 supplies the stored sheets to the printer section 17.

[0016] The printer unit 17 forms an image on the sheet based on image information generated by the image reading unit 16 or image information received via the communication channel. The printer unit 17 includes an image forming unit, a transfer unit, and a fixing device. The image forming unit forms an electrostatic latent image on the photoreceptor drum based on the image information. The image forming unit forms a visible image by attaching toner to the electrostatic latent image. The transfer unit transfers the visible image onto the sheet. The fixing device heats and pressurizes the toner to fix the visible image onto the sheet.

[0017] The paper discharge roller 19 is positioned near the paper discharge opening of the image forming apparatus body 100. The paper discharge roller 19 feeds the sheet on which the image has been formed to the sheet processing apparatus 200. The first control unit 90 controls the operation of each part of the image forming apparatus main body 100 and the sheet processing apparatus 200.

[0018] FIG. 2 is a block diagram showing a functional configuration example of the image forming apparatus 1. The image forming apparatus main body 100 includes a CPU (Central Processing Unit) 91, a memory 92, an auxiliary storage device 93, etc. connected by a bus, and executes a program. The image forming apparatus main body 100 functions as a device including a display unit 15, an operation unit 14, an image reading unit 16, a printer unit 17, a sheet storage unit 18, and a communication unit 94 by executing the program.

[0019] The CPU 91 functions as a first control unit 90 by executing programs stored in the memory 92 and the auxiliary storage device 93. The first control unit 90 controls the operations of each part of the image forming apparatus main body 100 and the sheet processing apparatus 200. The auxiliary storage device 93 is configured using a storage device such as a magnetic hard disk device or a semiconductor storage device. The auxiliary storage device 93 stores information. The communication unit 94 includes a communication interface for connecting the own device to an external device. The communication unit 94 communicates with an external device via the communication interface.

[0020] The sheet processing apparatus 200 will be described using FIG. 1. The sheet processing apparatus 200 performs post-processing on the sheet P on which an image is formed. For example, the post-processing is staple processing or saddle stitching processing, etc. The sheet processing apparatus 200 has a staple mechanism 20, a saddle stitching mechanism 30, and a second control unit (control unit) 95.

[0021] The staple mechanism 20 has a standby tray 21, a processing tray 22, and a stapler 23. The stapler 23 performs staple processing on the peripheral portions of a plurality of sheets P. The sheets P subjected to staple processing are conveyed by a conveyance belt 24 and discharged to a movable tray 27.

[0022] The sheet processing device 200 has a movable tray 27 and an upper tray 26. Stapled sheets P are discharged into the movable tray 27. Unstapled sheets P are discharged into the upper tray 26.

[0023] The saddle folding mechanism 30 includes a sheet support section 31, a processing section 33, and a booklet ejection section 40. The seat support section 31 supports the seat P. The seat support section 31 includes a saddle folding tray 32 and a lifting device 38. The saddle folding tray 32 can have a sheet P placed on its surface. The lifting device 38 supports the lower end of the sheet P placed on the saddle folding tray 32. The lifting device 38 moves up and down to move the sheet P to the processing unit 33.

[0024] The processing unit 33 includes a staple unit 34, a folding unit 35, and a folding unit 39. The staple section 34 is located above the folding unit 35. The staple section 34 applies stapling to a predetermined position on the sheet P. For example, the predetermined position on the sheet P is in the middle of the sheet P in the longitudinal direction.

[0025] The folding unit 35 is located in the center of the saddle folding mechanism 30. The folding unit 35 folds the sheet P in the middle along its longitudinal direction, creating a crease in the sheet P. The folding unit 35 has a blade 36 and a pair of folding rollers 37.

[0026] The blade 36 is flat and tapered. The blade 36 is movable between the front and back sides of the saddle folding tray 32. The blade 36 can contact the middle of the sheet P in the longitudinal direction. The pair of folding rollers 37 are located on the underside of the saddle folding tray 32. The pair of folding rollers 37 are aligned vertically. The axis of rotation of the pair of folding rollers 37 is parallel to the horizontal direction.

[0027] The fold-enhancing unit 39 is located downstream of the pair of folding rollers 37. The fold-enhancing unit 39 enlarges the folds of the sheet P.

[0028] For example, the saddle folding mechanism 30 performs a bookbinding process to form a booklet by saddle folding multiple sheets P. The lifting device 38 moves up and down while supporting the sheets P. The lifting device 38 positions the middle of the sheet P in the longitudinal direction at the position of the staple section 34. The staple section 34 applies a stapling process to the multiple sheets P. The lifting device 38 moves the multiple sheets P downwards. The lifting device 38 positions the middle of the sheet P in the longitudinal direction at the position of the folding unit 35. The blade 36 moves from the front to the back of the saddle folding tray 32 and pushes the sheet P between the pair of folding rollers 37. The multiple sheets P are saddle folded in the middle of their longitudinal direction, forming a booklet. The fold-adding unit 39 adds folds to the booklet. Thus, the booklet is completed. The booklet is discharged from the fold-adding unit 39 to the booklet discharge section 40.

[0029] The second control unit 95 controls the operation of each part of the sheet processing device 200. As shown in Figure 2, the sheet processing device 200 includes a CPU (Central Processing Unit) 96, memory 97, auxiliary storage device 98, etc., connected by a bus, and executes a program. Through program execution, the sheet processing device 200 functions as a device equipped with a stapling mechanism 20, a saddle folding mechanism 30, and a communication unit 99.

[0030] The CPU 96 functions as a second control unit (control unit) 95 by executing programs stored in the memory 97 and auxiliary storage device 98. The second control unit 95 controls the operation of each part of the sheet processing device 200. The auxiliary storage device 98 is configured using storage devices such as magnetic hard disk drives and semiconductor storage devices. The auxiliary storage device 98 stores information. The communication unit 99 is configured to include a communication interface for connecting itself to an external device. The communication unit 99 communicates with the external device via the communication interface.

[0031] The booklet ejection section 40 will be described in detail. Figure 3 is a front cross-sectional view of the booklet discharge unit 40. The booklet discharge unit 40 includes a discharge mechanism 50, a booklet tray 41, a booklet holder 42 (see Figure 1), and a damming member 44. As shown in Figure 1, the booklet discharge unit 40 is installed on the underside of the sheet processing device 200. The booklet Q is discharged from the discharge mechanism 50 and placed on the booklet tray 41.

[0032] Figure 4 is an enlarged view of the area around the discharge mechanism 50 in Figure 3. The discharge mechanism 50 has a pair of discharge rollers 51 and 52. The pair of discharge rollers 51 and 52 are a lower roller (first roller) 51 and an upper roller (second roller) 52. The lower roller 51 is rotatable around a lower rotation axis (first rotation axis) 51c. The upper roller 52 is rotatable around an upper rotation axis (second rotation axis) 52c. The upper roller 52 can contact the lower roller 51 to form a nip N. The pair of discharge rollers 51 and 52 convey and discharge the saddle-folded booklet Q (see Figure 6) diagonally downward by rotating it while gripping it with the nip N.

[0033] The X, Y, and Z directions of the Cartesian coordinate system are defined as follows for the local coordinate system of the booklet discharge section 40. The Y direction is parallel to the upper rotation axis 52c and the lower rotation axis 51c. The X direction is parallel to the contact line of the nip N in a cross section perpendicular to the upper rotation axis 52c. The +X side is the downstream side in the direction of transport and discharge of the booklet Q at the nip N. The Z direction (first direction) is the direction in which the lower rotation axis 51c and the upper rotation axis 52c are aligned. The +Z side is the side moving from the lower rotation axis 51c toward the upper rotation axis 52c.

[0034] The upper rotating shaft 52c is located vertically above the lower rotating shaft 51c. The upper rotating shaft 52c is located horizontally on the first side of the lower rotating shaft 51c. The horizontal first side (+H side) of the lower rotating shaft 51c is at an acute angle with the +X side of the lower rotating shaft 51c. As a result, the pair of discharge rollers 51 and 52 transport and discharge the booklet Q diagonally downward to the +X side.

[0035] Of the upper roller 52 and the lower roller 51, one is a drive roller and the other is a driven roller. The drive roller is rotationally driven by a motor (not shown). The driven roller rotates in accordance with the rotation of the drive roller. For example, the lower roller 51 is the drive roller and the upper roller 52 is the driven roller. Conversely, the upper roller 52 may be the drive roller and the lower roller 51 may be the driven roller.

[0036] The booklet tray 41 is formed in a flat shape parallel to the XY plane. The booklet tray 41 is located on the +X side of the discharge mechanism 50, and is positioned vertically below it. The booklet Q discharged from the discharge mechanism 50 is placed on the upper surface of the booklet tray 41 on the +Z side.

[0037] The booklet holder 42 is fixed to the upper surface of the booklet tray 41 on the +Z side, as shown in Figure 1. The booklet holder 42 is positioned near the +X end of the booklet tray 41. A booklet Q placed on the upper surface of the booklet tray 41 can come into contact with the -X side surface of the booklet holder 42.

[0038] The damming member 44 is positioned on the +Z side of the booklet tray 41, as shown in Figure 3. The damming member 44 is positioned on the +X side of the discharge mechanism 50 and on the -X side of the booklet holder 42 (see Figure 1). The damming member 44 is formed in an L shape when viewed from the Y direction. The damming member 44 is rotatable around the pivot axis 45. The leading edge of a booklet Q discharged from the nip N of the discharge mechanism 50 comes into contact with the damming member 44. The damming member 44 temporarily holds the booklet Q. Later discharged booklets Q are placed on the +Z side of the booklet Q that was discharged earlier and held by the damming member 44. When the leading edges of multiple booklets Q come into contact with the damming member 44, the damming member 44 rotates to the +Z side. Booklet Q passes under the -Z side of the damming member 44 and moves to the booklet holder 42.

[0039] The booklet ejection section 40 may have an opening stopper member 60. The opening stopper member 60 is positioned on the +Z side of the booklet tray 41. The opening stopper member 60 is positioned on the +X side of the discharge mechanism 50 and on the -X side of the damming member 44. The opening stopper member 60 contacts the upper surface of the booklet Q placed on the booklet tray 41. The opening stopper member 60 prevents the saddle-folded booklet Q from opening upwards. The pair of discharge rollers 51 and 52 are separated into two locations in the Y direction, with an opening stopper member 60 in between.

[0040] As shown in Figure 3, the discharge mechanism 50 has a cover 55. The cover 55 is formed from a resin material or the like. The cover 55 covers the outer circumference of the upper roller 52 on the first horizontal side (+H side) of the upper roller 52. The cover 55 extends over the entire Y-direction of the upper roller 52. The Y-direction end of the cover 55 covers the Y-direction end face of the upper roller 52.

[0041] Figures 3 and 4 show cross-sections perpendicular to the upper rotation axis 52c. In Figure 4, the line containing the contact line of the nip N is defined as the first line L1. The line parallel to the first line L1 and passing through the upper rotation axis 52c is defined as the second line L2. The lower end portion 55d of the cover 55 is positioned between the first line L1 and the second line L2 in the Z direction.

[0042] Figure 7 is an explanatory diagram of the operation of the discharge mechanism 50p in the prior art. The pair of discharge rollers 51 and 52 rotate the saddle-folded booklet Q by gripping it with the nip N, thereby discharging the booklet Q to the +X side.

[0043] As shown in the left diagram of Figure 7, the discharged booklet Q spreads out vertically. That is, the lower part of the booklet Q, Qd below the fold, and the upper part of the booklet Qu, Qu above the fold, separate vertically. The -X side end of the lower part of the booklet Qd contacts the outer surface of the lower roller 51. The -X side end of the upper part of the booklet Qu springs up on the +Z side of the nip N.

[0044] As shown in the right-hand diagram of Figure 7, the lower part Qd of the booklet is scraped off to the -Z side by the rotation of the lower roller 51. Even after the lower part Qd is scraped off, the upper part Qu of the booklet remains on the +Z side of the nip N. The second booklet Q is discharged following the first booklet Q. The second booklet Q gets stuck between the upper part Qu and the lower part Qd of the first booklet Q. This results in improper loading of the booklet Q.

[0045] Figure 6 is an explanatory diagram of the operation of the discharge mechanism 50 in the embodiment. As shown in the left diagram of Figure 6, the -X side end of the upper part Qu of the booklet abuts against the lower end 55d of the cover 55. This restricts the upper part Qu of the booklet from bouncing up to the +Z side. A portion of the upper part Qu of the booklet contacts the outer circumferential surface of the lower roller 51. As shown in the right diagram of Figure 6, a portion of the upper part Qu of the booklet is scraped off to the -Z side by the rotation of the lower roller 51. In conjunction with this, the remaining part of the upper part Qu of the booklet also falls to the -Z side. The entire booklet Q falls to the -Z side of the nip N. Following the first booklet Q, the second booklet Q is discharged. The second booklet Q is placed on the +Z side of the upper part Qu of the first booklet Q. This suppresses improper loading of the booklets Q.

[0046] As described above, the lower end 55d of the cover 55 is positioned between the first straight line L1 and the second straight line L2 in the Z direction. The lower end 55d of the cover 55 is positioned as far to the -Z side as possible without blocking the +X side of the nip N. This restricts the upward movement of the upper part Qu of the booklet towards the +Z side. Most of the upper part Qu of the booklet comes into contact with the outer surface of the lower roller 51. The entire booklet Q is prone to falling towards the -Z side. Therefore, improper loading of the booklet Q is suppressed.

[0047] In the cover 55, the +Z side of the second straight line L2 is the upper part of the cover 56, and the -Z side of the second straight line L2 is the lower part of the cover 57. In Figure 4, the upper part of the cover 56 is arc-shaped with respect to the upper rotation axis 52c. The lower part of the cover 57 is straight and extends from the lower end of the upper part of the cover 56 toward the -Z side. The lower end 55d of the lower part of the cover 57 is separated from the outer surface of the upper roller 52 toward the +X side. As a result, the upper part of the booklet Qu is less likely to bounce up toward the +Z side through the +X side of the cover 55. Therefore, improper loading of the booklet Q is suppressed.

[0048] In the saddle folding mechanism 30 shown in Figure 1, the middle of the longitudinal direction of the sheet P is saddle-folded to form a booklet Q. The saddle folding mechanism 30 processes sheets P of various sizes. A-series sizes such as A3 or A4 are specified in the international standard ISO 216, which defines paper dimensions. B-series sizes such as B5 are specified in ISO 216 or the Japanese Industrial Standard JIS-B series. Envelope sizes are specified as the C series in ISO 269. Letter size LT is specified as ANSI A in the American National Standards Institute ANSI / ASME Y14.1. LG is legal size. ST-R is statement size, which is half the size of letter size.

[0049] As described above, the leading edge of the booklet Q discharged from the discharge mechanism 50 shown in Figure 3 comes into contact with the damming member 44. Larger booklets Q come into contact with the damming member 44 during or immediately after discharge by the discharge mechanism 50. Smaller booklets Q fall into the booklet tray 41 after discharge by the discharge mechanism 50, slide along the top surface of the booklet tray 41, and come into contact with the damming member 44. The time from discharge by the discharge mechanism 50 to contact with the damming member 44 is longer for smaller booklets Q than for larger booklets Q. The middle of the longitudinal direction of an A4 size booklet is saddle-folded to form an A5 size booklet Q. The A5 size booklet Q is the smallest size booklet Q.

[0050] The second control unit 95 controls the rotation of the lower roller 51, which is a drive roller. The second control unit 95 continues to rotate the lower roller 51 until at least an A5-sized booklet Q is discharged from the nip N of the discharge mechanism 50, and until the leading edge of the booklet Q contacts the damming member 44. The second control unit 95 also continues to rotate the lower roller 51 for the same amount of time after other sizes of booklets Q are discharged by the discharge mechanism 50. As a result, the lower roller 51 continues to rotate until all sizes of booklets Q contact the damming member 44. The rotation of the lower roller 51 scrapes off parts of the lower part Qd and upper part Qu of the booklet to the -Z side. Therefore, improper loading of the booklets Q is suppressed.

[0051] The driven upper roller 52 is biased toward the driven lower roller 51. When a thick sheet is saddle-folded, a thick booklet Q is formed. When the thick booklet Q enters the nip N of the discharge mechanism 50, the upper roller 52 moves toward the +Z side. This makes it easier for the thick booklet Q to enter the nip N and prevents it from being unable to be discharged. The cover 55 is movable in the Z direction together with the upper roller 52. When the thick booklet Q enters the nip N, the cover 55 moves toward the +Z side together with the upper roller 52. Even when the thick booklet Q enters the nip N, the cover 55 does not block the +X side of the nip N. This prevents the thick booklet Q from being unable to be discharged.

[0052] The booklet Q discharged from the discharge mechanism 50 is placed on the booklet tray 41. The user of the image forming apparatus 1 reaches into the booklet tray 41 and picks up the booklet Q. As shown in Figure 1, the upper roller 52 is positioned near the outside of the image forming apparatus 1. The user's hand may come into contact with the rotating upper roller 52. As shown in Figure 4, the cover 55 covers the outer circumference of the upper roller 52 on the first horizontal side (+H side) of the upper roller 52. The +H side of the upper roller 52 corresponds to the outside of the image forming apparatus 1. This prevents the user's hand from coming into contact with the upper roller 52.

[0053] Figure 5 is an enlarged view of the area around the discharge mechanism 50 in a modified embodiment. Figure 5 is a cross-section perpendicular to the upper rotating shaft 52c. In Figure 5, the third straight line L3 is defined as a straight line parallel to the first straight line L1 and tangent to the outer circumference of the upper roller 52 on the +Z side (upper side) of the upper rotating shaft 52c. It is desirable that the upper end portion 55u of the cover 55 be positioned on the +Z side (upper side) of the third straight line L3. This ensures that most of the first horizontal side (+H side) of the upper roller 52 is covered by the cover 55. This prevents the user's hand from coming into contact with the upper roller 52.

[0054] As mentioned above, the cover 55 extends over the entire Y-axis of the upper roller 52. This prevents the user's hand from coming into contact with the upper roller 52. As shown in Figure 3, the exterior member 58 of the sheet processing device 200 is positioned on the +Z side of the upper roller 52. It is desirable to form the exterior member 58 such that its lower end on the -Z side is positioned close to the upper roller 52. Even in this case, it is possible to prevent the user's hand from coming into contact with the upper roller 52.

[0055] As detailed above, the sheet processing apparatus 200 of the embodiment includes a lower roller 51, an upper roller 52, and a cover. The lower roller 51 is rotatable around a lower rotation axis 51c. The upper roller 52 is rotatable around an upper rotation axis 52c which is above the lower rotation axis 51c and on the first horizontal side of the lower rotation axis 51c. The upper roller 52 can contact the lower roller 51 to form a nip N, and the saddle-folded booklet Q can be transported diagonally downward by gripping the booklet Q in the nip N and rotating it. In a cross section perpendicular to the upper rotation axis 52c, the line containing the contact line of the nip N is defined as the first line L1, and the line parallel to the first line L1 and passing through the upper rotation axis 52c is defined as the second line L2. The cover 55 covers the outer circumference of the upper roller 52 on the first horizontal side of the upper roller 52, and its lower end 55d is positioned between the first straight line L1 and the second straight line L2.

[0056] The upper part Qu of the booklet Q discharged from the nip N bounces up towards the +Z side of the nip N. The lower end 55d of the cover 55 is positioned near the +Z side of the nip N. The lower end 55d of the cover 55 restricts the upward bouncing of the upper part Qu of the booklet towards the +Z side. The entire booklet Q is more likely to fall towards the -Z side of the nip N. This suppresses improper loading of the booklet Q and prevents a decrease in the processing quality of the sheet processing device 200. Since the cover 55 covers the outer circumference of the upper roller 52, it is possible to prevent the user's hand from coming into contact with the upper roller 52.

[0057] In a cross-section perpendicular to the upper rotation axis 52c, the third straight line L3 is defined as a straight line parallel to the first straight line L1 and tangent to the outer circumference of the upper roller 52 above the upper rotation axis 52c. The upper end portion 55u of the cover 55 is positioned above the third straight line L3. As a result, most of the upper roller 52 is covered by the cover 55. Therefore, it is possible to prevent the user's hand from coming into contact with the upper roller 52.

[0058] The cover 55 extends over the entire axial range of the upper roller 52. This prevents the user's hand from coming into contact with the upper roller 52.

[0059] Of the lower roller 51 and the upper roller 52, one is a driven roller and the other is a driven roller. The sheet processing device 200 further includes a second control unit 95 and a damming member 44. The second control unit 95 controls the rotation of the driven roller. The leading edge of the booklet Q discharged from the nip N can come into contact with the damming member 44. The second control unit 95 continues to rotate the driven roller after at least an A5-sized booklet Q has been discharged from the nip N, until the leading edge of the booklet Q comes into contact with the damming member 44.

[0060] As a result, the lower roller 51 and the upper roller 52 continue to rotate until booklets of all sizes Q come into contact with the damming member 44. The rotation of the lower roller 51 scrapes the booklets Q to the -Z side. This suppresses improper loading of booklets Q and prevents a decrease in the processing quality of the sheet processing device 200.

[0061] The direction in which the lower rotation axis 51c and the upper rotation axis 52c are aligned is defined as the Z direction. The cover 55 is movable in the Z direction together with the upper roller 52. When the thick booklet Q enters the nip N, the cover 55 moves to the +Z side together with the upper roller 52. Since the cover 55 does not block the +X side of the nip N, the inability to eject the thick booklet Q is suppressed.

[0062] According to at least one embodiment described above, the upper roller 52 has a cover 55 that covers the outer circumference of the upper roller 52 on the first horizontal side of the upper roller 52, with its lower end 55d positioned between the first straight line L1 and the second straight line L2. This makes it possible to suppress a decrease in the processing quality of the sheet processing device 200.

[0063] While several embodiments of the present invention have been described, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These embodiments can be carried out in a variety of other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims and their equivalents. [Explanation of symbols]

[0064] L1...First straight line, L2...Second straight line, L3...Third straight line, N...Nip, Q...Booklet, 44...Borestation member, 51...Lower roller (first roller), 51c...Lower rotating shaft (first rotating shaft), 52...Upper roller (second roller), 52c...Upper rotating shaft (second rotating shaft), 55...Cover, 55d...Lower end, 55u...Upper end, 95...Second control unit (control unit), 200...Sheet processing device.

Claims

1. A first roller that can rotate around a first rotation axis, A second roller is rotatable around a second rotation axis located above the first rotation axis and on the first horizontal side of the first rotation axis, capable of contacting the first roller to form a nip, and capable of transporting a saddle-folded booklet diagonally downward by gripping the booklet in the nip and rotating it. In a cross-section perpendicular to the second axis of rotation, when the line containing the contact line of the nip is defined as the first line, and the line parallel to the first line and passing through the second axis of rotation is defined as the second line, The second roller has a cover that covers the outer circumference of the second roller on the first horizontal side of the second roller, with its lower end positioned between the first straight line and the second straight line, Sheet processing device.

2. In a cross-section perpendicular to the second axis of rotation, when a third straight line is defined as a straight line parallel to the first straight line and tangent to the outer circumference of the second roller above the second axis of rotation, The upper end of the cover is positioned above the third straight line. The sheet processing apparatus according to claim 1.

3. The cover extends over the entire axial range of the second roller, The sheet processing apparatus according to claim 1 or 2.

4. Of the first roller and the second roller, one is a driving roller and the other is a driven roller. A control unit that controls the rotation of the drive roller, The system further includes a damming member to which the leading edge of the booklet discharged from the nip can make contact, The control unit continues to rotate the drive roller after at least an A5-sized booklet has been ejected from the nip, until the leading edge of the booklet contacts the damming member. The sheet processing apparatus according to claim 1 or 2.

5. When the direction in which the first axis of rotation and the second axis of rotation are aligned is defined as the first direction, The cover is movable in the first direction together with the second roller. The sheet processing apparatus according to claim 1 or 2.

Images