JP2012051298A - Saddle stitch bookbinding device, and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To arrange and bind sheets.SOLUTION: The saddle stitch bookbinding device 23 includes: a creasing unit 4 that creases a middle portion of a sheet orthogonally to a sheet conveying direction; a control roller pair 31 that conveys the sheet creased by the creasing unit; a stopper that matches the ends in the sheet conveying direction of a plurality of creased sheets conveyed by the control roller pair; a saddle stitch stapler that binds a portion being the spine of the sheet matched by the stopper when the sheet is bent; and a bending mechanism that bends the creased portion of the sheet. The control roller pair flattens the creased portion while conveying the sheet. Therefore, the sheet is matched by the stopper, to be easily superimposed, arranged and bound.

Description

  The present invention relates to a saddle stitch bookbinding apparatus that performs saddle stitching after folding a sheet and then folds the fold, and an image forming apparatus including the saddle stitch bookbinding apparatus.

  2. Description of the Related Art Conventionally, there is a sheet post-processing apparatus as a saddle stitch binding apparatus that performs saddle stitching, bookbinding in a U-shape, and flattening the back (square saddle) (Patent Document 1). This paper post-processing device collects one sheet at a time or several sheets, makes the binding portion U-shaped, hooks and stacks on a paper stacking section with a triangular cross section, and saddle-stitches into a U-shape. It is supposed to be bound.

JP 2006-219296 A

  However, in the conventional paper post-processing device, when the sheet binding portion is formed in a U shape and is stacked on a paper stacking portion having a triangular cross section, the portions folded in a U shape may be displaced from each other. Sheets may be bound in a state where the sheets are not aligned.

  For this reason, the conventional paper post-processing apparatus has a problem to be solved that the sheets are bound together in an irregular manner.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a saddle stitch bookbinding apparatus capable of aligning sheets and binding and an image forming apparatus including the apparatus.

  The saddle stitch bookbinding apparatus according to the present invention is a saddle stitch bookbinding apparatus that binds and folds an intermediate portion of a sheet, and a crease unit that folds the intermediate portion of the sheet perpendicular to the sheet conveyance direction, and a crease formed by the crease unit. A pair of conveying rollers for conveying the attached sheets, an aligning unit for aligning ends of the plurality of creased sheets conveyed by the pair of conveying rollers in the sheet conveying direction, and aligned by the aligning unit. And a folding means for folding the creased portion of the sheet, and the conveying roller pair is creased while conveying the creased sheet. It is characterized by flattening the part.

  An image forming apparatus according to the present invention includes: an image forming unit that forms an image on a sheet; and the saddle stitch bookbinding device that processes the sheet, and the saddle stitch bookbinding apparatus forms an image by the image forming unit. The sheet is folded, aligned and bound, and the fold portion is folded.

  The saddle stitch bookbinding apparatus of the present invention flattens a creased portion of the sheet while the pair of conveying rollers conveys the creased sheet to the aligning means, and the aligning means flattens the creased portion of the sheet. The ends in the transport direction are aligned. For this reason, the saddle stitch bookbinding apparatus eliminates the rise of the folds and aligns the sheets by the aligning means, so that the sheets can be bound with less shift in the relative positional relationship between the folds of the sheets. Therefore, the saddle stitch bookbinding apparatus of the present invention can bind and bend the sheet with less deviation between the sheets.

  Since the image forming apparatus of the present invention includes the saddle stitch bookbinding apparatus that can bind sheets together, it is not necessary to form an image on the sheet again, and the image forming efficiency can be improved.

FIG. 3 is a cross-sectional view of the image forming apparatus according to the embodiment of the present invention and a sheet processing apparatus including the saddle stitch binding apparatus according to the embodiment of the present invention connected to the apparatus main body of the image forming apparatus along the sheet conveying direction. It is a cross-sectional schematic diagram along the sheet conveyance direction of the creasing unit of the saddle stitch bookbinding apparatus in the embodiment of the present invention. It is an external appearance schematic perspective view of a creasing unit. It is operation | movement explanatory drawing of a creasing unit. It is operation | movement explanatory drawing of the creasing unit following FIG. It is explanatory drawing of the saddle stitching operation | movement and folding operation | movement of a saddle stitch bookbinding apparatus. It is a perspective view of a U-shaped bookbinding formed by the saddle stitch bookbinding apparatus. It is a figure which shows the dimensional relationship of the bending part of a sheet | seat. It is a control block diagram of a saddle stitch binding apparatus. It is a flowchart for operation | movement description of a saddle stitch bookbinding apparatus.

  Hereinafter, a sheet processing apparatus including a saddle stitch binding apparatus according to an embodiment of the present invention and an image forming apparatus including the sheet processing apparatus will be described with reference to the drawings. In addition, a numerical value is a reference numerical value, Comprising: It is not a numerical value which limits this invention.

  In FIG. 1, a sheet processing apparatus 2 is connected to the apparatus main body 1 </ b> A of the image forming apparatus 1. The sheet processing apparatus 2 is separate from the apparatus main body 1A, but may be incorporated in the apparatus main body 1A.

  The apparatus main body 1A of the image forming apparatus 1 has an automatic document feeder 5 and an image reading device 6 for reading a document automatically supplied by the automatic document feeder 5 placed on top of each other.

  The apparatus main body 1A of the image forming apparatus 1 is configured to copy an image on a sheet based on read information obtained by the image reading apparatus 6 reading a document. Read information obtained by reading the document by the image reading device 6 is formed as a latent image on the photosensitive drum 8 by the laser scanner 7. The latent image is developed with toner by the developing device 9 to become a toner image.

  On the other hand, the sheet P stored in the cassette 10 is sent out from the cassette 10 by the pickup roller 11 and is sent between the photosensitive drum 8 and the transfer roller 12. The transfer roller 12 transfers the toner image on the photosensitive drum 8 to a sheet. The sheet to which the toner image has been transferred is heated and pressed by the fixing device 13 to fix the toner image.

  Thereafter, the sheet is discharged to the in-body discharge tray 14 or sent to the sheet processing apparatus 2 through the communication path 15. When a toner image is also formed on the other side of the sheet, the sheet is conveyed switchback using the communication path 15 and sent to the reversing path 16 in an inverted state, and again with the photosensitive drum 8. It is fed between the transfer roller 12. As a result, a toner image is also formed on the other side of the sheet, and the sheet is discharged to the in-body discharge tray 14 or conveyed to the sheet processing apparatus 2.

  The sheet processing apparatus 2 includes a sheet discharge path 21, an end binding bookbinding device 22, a saddle stitch bookbinding device 23, an upper tray 24 and a lower tray 25 that can be raised and lowered, a bookbinding tray 26, and the like.

  The sheet discharge path 21 guides a sheet on which an image is formed by the apparatus main body 1A of the image forming apparatus to the upper tray 24 or the lower tray 25.

  The edge binding apparatus 22 sequentially stacks sheets on which images are formed by the apparatus main body 1 </ b> A of the image forming apparatus onto the processing tray 27, binds the edges, binds the sheets, and discharges them to the upper tray 24 or the lower tray 25. It is like that.

  The saddle stitch bookbinding apparatus 23 sequentially stacks sheets on which an image is formed by the apparatus main body 1A on a stopper 28, binds an intermediate portion thereof, folds it into a booklet, and discharges it to a bookbinding tray 26.

  The saddle stitch bookbinding apparatus 23 will be described.

  The saddle stitch bookbinding apparatus 23 (FIG. 1) binds and bends the middle part of the sheet to perform saddle stitch bookbinding. The saddle stitch bookbinding apparatus 23 mainly includes the following constituent elements. A crease unit 4 serving as a crease unit that creases a middle portion of the sheet perpendicular to the sheet conveyance direction. A control roller pair 31 as a pair of conveyance rollers that can convey the sheet to the crease unit 4 and stops conveyance of the sheet when the crease unit 4 creases the sheet. A stopper 28 as an aligning unit that aligns the ends of the plurality of creased sheets conveyed by the control roller pair 31 in the sheet conveying direction. A saddle stitch stapler 32 as a binding means for binding an intermediate portion of the sheet aligned by the stopper 28, that is, a portion that becomes a back when the sheet is folded. A folding means and a folding mechanism 33 for folding a creased portion of the sheet; These components and the like are controlled by a CPU 34 as control means shown in FIG.

  The CPU 34 (FIG. 9) temporarily stores predetermined information of the sheet processing apparatus, for example, the ROM 36 for storing the control sequence based on the flowchart shown in FIG. 10, the occasional information of the sheet processing apparatus, and the like. And a RAM 37. The CPU 34 is connected to a tip detection sensor 20 described later and crease plate HP (home position) sensors 48U and 48D.

  The CPU 34 is also connected with a control roller pair conveyance motor M1 and crease motors MU and MD, which will be described later.

  Further, the CPU 34 receives information such as sheet size data information and sheet count information. The sheet size data information is sent when the user starts the image forming apparatus and selects the sheet size and inputs it to the operation panel 17 (FIG. 1). The sheet count information is sent by a counter (not shown) provided in the apparatus main body 1A of the image forming apparatus. Note that the sheet count information may be detected by a sensor (not shown) provided in the CPU 34 based on the detection information of the sensor. Since the number of sheets is previously input to the operation panel 17 by the user, the CPU 34 stops the saddle stitch binding process when the input number and the number of sheets according to the sheet count information become the same. Yes.

  The sheet processing apparatus 2 has a sheet conveyance path 35 (FIG. 2) for guiding the sheet P conveyed from the apparatus main body 1A of the image forming apparatus 1. On both upper and lower sides of the sheet conveying path 35, an upper crease portion 41U and a lower crease portion 41D of the sheet crease unit 4 are arranged.

  The upper crease portion 41U and the lower crease portion 41D have a vertically symmetrical shape with the sheet conveyance path 35 therebetween. Therefore, in the upper crease portion 41U and the lower crease portion 41D, the same number is given to the member having the same shape, the member of the upper crease portion 41U is given U at the end of the number, and the lower crease The member of the attaching portion 41D is marked with D at the end of the number.

  The upper crease 41U and the lower crease 41D have U-shaped casings 42U and 42D arranged at right angles to the sheet conveying direction A. In the casings 42U and 42D, a pair of side guides 44U and 44D, which are brought into contact with each other by pressing springs 43U and 43D, are provided.

  The casings 42U and 42D are provided with crease plates 45U and 45D as crease members that crease the sheet by protruding the sheet in the thickness direction so as to be movable in the vertical direction. The pair of crease plates 45U and 45D are arranged with their tips spaced apart and opposed to both sides of a sheet conveyance path 35 as a path through which the sheet passes. As will be described later, the sheets are alternately projected from both sides. It is designed to make a crease.

  As shown in FIG. 3, the casings 42U and 42D, the creasing plates 45U and 45D, and the side guides 44U and 44D are long members that are arranged at right angles to the sheet conveying direction.

  The creasing plates 45U and 45D (FIG. 2) are urged in a direction away from the side guides 44U and 44D by the return springs 46U and 46D, and the rear ends thereof are turned to cams 47U and 47D rotated by the creasing motors MU and MD. Always in contact.

  A control roller pair 31 that is rotated by a control roller pair transport motor M1 is provided downstream of the creasing unit 4 in the sheet transport direction A. The control roller pair 31 is also a registration roller pair that receives the leading edge of the sheet before creasing and corrects the skew of the sheet in a state where the rotation is stopped.

  A tip detection sensor 20 as a detection unit is provided downstream of the control roller pair 31. The leading edge detection sensor 20 detects the leading edge of the sheet, and detects that the control roller pair 31 has conveyed the creased portion of the sheet to the leading edges of the creasing plates 45U and 45D of the creasing unit 4. It has become.

  The operation of the saddle stitch binding apparatus 23 will be described.

  The user inputs information necessary for forming an image on the sheet, such as the sheet size and the number of sheets to be processed, and information necessary for processing the sheet, on an operation panel 17 (FIG. 1) provided in the apparatus main body 1A. Then, the CPU 34 receives such information (S1 in FIG. 10).

  Then, the sheet on which the image is formed is sent from the apparatus main body 1A (FIG. 1) of the image forming apparatus to the sheet processing apparatus 2. The leading end (downstream end in the sheet conveying direction) of the fed sheet P is guided through the sheet conveying path 35 (FIG. 2), passes through the creasing unit 4 and reaches the control roller pair 31. The control roller pair 31 not only conveys the sheet but also serves as a registration roller pair, and therefore receives the leading edge of the sheet in a state where the rotation is stopped. Since the rear end portion of the sheet continues to be conveyed, the sheet is looped to correct skew (S2 in FIG. 10). After the skew of the sheet is corrected, the CPU 34 starts the control roller pair conveyance motor M1 to rotate the control roller pair 31. The control roller pair 31 conveys the sheet.

  Here, based on FIG. 8, the position where the sheet is creased by the crease plates 45U and 45D will be described. FIG. 8A is a diagram of a state when the sheet is bent. FIG. 8B is a diagram of the state when the sheet is not bent.

  As shown in FIGS. 7 and 8, the saddle stitch bookbinding device 23 binds the sheets and folds them into a U-shape to perform bookbinding. Therefore, the saddle stitch bookbinding apparatus 23 is configured to attach two folds to the sheet in order to easily fold the sheet into a U-shape. The saddle stitch bookbinding apparatus 23 has two folds at the same distance (L1) between the center PC (FIG. 8) in the sheet conveyance direction and the upstream and downstream in the sheet conveyance direction (positions of symbols PA and PB). The sheet is attached at a right angle to the sheet conveying direction. The central PC in the sheet conveyance direction of the sheet is a position that is half (L / 2) of the total length L in the sheet conveyance direction of the sheet. In this case, since the sheets are stacked, according to the thickness of the sheet, the interval between the two folds (2 · L2) of the outer sheet P2 is the interval between the folds (2 · L1) of the inner sheet P1. It is necessary to set wider (2 · L2> 2 · L1).

  In the present embodiment, the sheet P is bent in a direction shown in FIGS. 6D, 7 and 8A by a thrust plate 52 of a bending mechanism 33 (FIGS. 1 and 6) described later. Yes. Therefore, the leading edge PS (FIG. 8) of the sheet is received by the stopper 28 (FIG. 6B).

  The sheets are fed into the stopper 28 sequentially from the inner sheet when folded by the folding mechanism 33. For this reason, it is necessary to feed the crease unit 4 first from the inner sheet. Further, the crease unit 4 needs to attach a crease (first crease) PA close to the leading end of the sheet to the sheet first, and then attach a distant crease (second crease) PB to the sheet.

  Accordingly, the control roller pair 31 rotates until the portion to which the first crease PA is attached is conveyed between the front ends of the crease plates 45U and 45D after the front end detection sensor 20 detects the front end PS of the sheet P1. And convey the sheet. The control roller pair 31 stops the conveyance of the sheet when the portion where the first crease PA is attached reaches between the leading ends of the crease plates 45U and 45D (S2 in FIG. 10). The sheet conveyance amount at this time can be detected by the CPU 34 detecting the number of rotations of the control roller pair conveyance motor M1. Further, the distance L3 from the leading edge PS of the sheet P1 to the first fold line PA is obtained from ((total length L / 2 of the sheet) −L1).

  Thereafter, the CPU 34 starts the lower crease motor MD (FIG. 2) to rotate the cam 47D. Then, the cam 47D is a long-diameter portion, and raises the lower crease plate 45D against the return spring 46D (FIG. 2) (FIG. 4A). The creasing plate 45D passes between the pair of side guides 44D that are opposed to each other by the pressing spring 43D, and enters between the upper pair of side guides 44U. At this time, the creasing plate 45D is guided by the inclined guide surface 44Ua (FIG. 2) of the side guide 44U and pushes the sheet into the side guide 44U. At this time, the sheet, together with the crease plate 45D, pushes away the pair of side guides 44U against the pressing spring 43U and slightly enters between the pair of side guides 44U. (S3 in FIG. 4A and FIG. 10).

  The cam 47D continues to rotate so that the creasing plate 45D can be restored at the short diameter portion. The crease plate 45D is pulled out of the side guides 44U and 44D by the return spring 46D and returned to the original position, and is detected by the crease HP sensor 48D. The CPU 34 stops the rotation of the crease motor MD by the detection operation of the crease HP sensor 48D. The side guides 44U and 44D return to the original attached state by the pressing springs 43U and 43D.

  Thereafter, the CPU 34 starts the upper crease motor MU (FIG. 2), rotates the cam 47U, and resists the upper crease plate 45U against the return spring 46U (FIG. 2) at the long diameter portion of the cam 47U. And descends (FIG. 4B). At this time, the sheet remains stopped without being conveyed to the control roller pair 31.

  Similarly to the lower crease plate 45D, the upper crease plate 45U pushes the side guides 44U, 44D against the press springs 43U, 43D, and enters between the side guides 44U, 44D to enter the seat. Is pushed between the side guides 44D (FIGS. 4B and 4C). A guide surface 44Da for guiding the creasing plate 45U is also formed on the lower side guide 44D. The upper side guide 44U also comes out of the side guides 44D and 44U by the return spring 46U and returns to the original position (FIG. 4D).

  As a result, the sheet is projected from the upper side to the lower side by the upper crease plate 45U, and the first crease is given to the portion that is projected from the lower side to the upper side by the lower crease plate 45D. . In other words, the sheet is alternately projected from the lower side and the upper side by the crease plates 45U and 45D, and the first crease PA is reliably attached (S4 in FIG. 10).

  When the crease plate HP sensor 48U detects that the upper crease plate 45U has returned to the original position, the CPU 34 starts the control roller pair conveyance motor M1 to rotate the control roller pair 31. In the CPU 34, the control roller pair 31 conveys the sheet P1 (FIG. 8B) by a distance 2 · L1 (conveys a predetermined distance), and the second crease portion is located between the crease plates 45U and 45D. At the time, the control roller pair conveyance motor M1 is stopped (S5 in FIG. 10).

  The CPU 34 causes the crease unit 4 to push the sheet downward by the upper crease plate 45U (FIG. 5A, S6 in FIG. 10). Thereafter, the CPU 34 pushes the sheet upward by the lower crease plate 45D (FIG. 5B). The sheet is alternately projected from the upper side and the lower side by the crease plates 45U and 45D, and the second crease PB is reliably attached (S7 in FIG. 10).

  In the above operation, when the first and second folds PA and PB are formed on the sheet by the crease plates 45U and 45D protruding from the sheet, the position of the sheet is shifted by the pushing operation of the crease plate. In some cases, the crease cannot be placed at the proper position.

  Therefore, the control roller pair 31 of the present embodiment can hold the sheet when the crease is made by the crease unit 4 with a nip pressure that stops the rotation and does not cause the sheet to be displaced. Thus, the sheet can be creased at a normal position without being displaced by the pushing operation of the crease plates 45U and 45D.

  When the crease HP sensor 48D detects that the crease plate 45D with the second crease PB has returned to the original position, the CPU 34 starts the control roller pair conveyance motor M1 (FIG. 5C). The control roller pair 31 conveys the creased sheet to the folding mechanism 33 (FIG. 1), at which time the control roller pair 31 nipping the nip while rotating and conveying the sheet. The sheet is creased by the pressure (nip pressure) to flatten the slightly raised portion (FIG. 5D, S8 in FIG. 10) In this case, the rollers 31a and 31b of the control roller pair 31 (FIG. 3) is a continuous cylindrical roller that can hold the entire direction (sheet width) perpendicular to the sheet conveying direction of the sheet, and the entire creased portion. Can be flattened. And flattening the other words, the habit folding crease attached to the sheet by creasing unit 4 is to weak.

  In the creasing unit 4, after the control roller pair 31 feeds the first sheet P1 to the folding mechanism 33 (FIG. 1), the subsequent second sheet P2 is also applied to the second sheet P2 in the same manner as the first sheet P1. First and second fold lines PA and PB are provided at the positions shown in FIG.

  In this case, in the present embodiment, the second sheet P2 is superposed on the outside of the first sheet P1 (outside of the first sheet when folded by the folding mechanism 33). Yes. For this reason, the interval (2 · L2) between the two folds of the outer sheet P2 is wider (2 · L2) depending on the thickness of the sheet than the interval (2 · L1) of the inner sheet P1. > 2 · L1). Therefore, based on the control of the CPU 34, the control roller pair 31 sets the distance to convey the sheet between the first crease and the second crease after the crease plate makes the first crease (the first sheet ( It can be changed between the preceding sheet) and the second sheet (following sheet). Thus, the crease unit 4 can change the distance between the first fold and the second fold by changing the distance for conveying the sheet.

  Thereafter, the subsequent sheets are also creased in the same manner with the interval between the first crease and the second crease being sequentially increased. Note that the interval between the first crease and the second crease may not be widened for each sheet, but may be widened for every several sheets.

  When the number of sheets to be creased reaches the number input by the user, the CPU 34 stops the operations of the crease unit 4 and the control roller pair 31 because the sheets are not sent from the apparatus main body 1A.

  The creased sheet is received by the stopper 28 of the folding mechanism 33 with the front end PS facing downward (FIG. 6A). The sheets are sequentially stacked on a pair of folding rollers 53 (to be described later) to form a bundle.

  In this case, since the creased portion of the sheet is flattened by the control roller pair 31, the sheet is free from shrinkage of the sheet length caused by the crease and rising. Further, when the sheets are overlapped, the crease is raised, so that almost no gap is generated between the sheets. Therefore, the leading edges of the sheets are aligned and the central PCs (FIG. 8) are aligned at the same position. Further, the first creases PA and the second creases PB are also shifted and aligned with each other by the thickness of the sheet.

  Since the stopper 28 stands by at a position where the center PC (FIG. 8) of the sheet coincides with the binding position of the saddle stitching stapler 32, the center PC of the sheet is bound when the saddle stitching stapler 32 is operated. The saddle stitching stapler 32 does not necessarily have to bind the center PC of the sheet, and when the sheet is folded, a portion that becomes a back PW (FIG. 7) between the first fold line PA and the second fold line PB. Can be bound. In FIG. 7, the code | symbol 51 shows the needle | hook which bound the sheet | seat.

  Thereafter, the stopper 28 descends and stops descending when the center PC of the sheet faces the tip of the pushing plate 52 of the bending mechanism 33 (FIG. 6B). The distance between the first fold and the second fold is 2 mm for the first to fifth sheets, 3 mm for the sixth to tenth sheets, and 4 mm for the eleventh to fifteenth sheets. For this reason, in this embodiment, the thickness of the veneer 52 is set to 2 mm in accordance with the crease interval from the first sheet to the fifth sheet.

  The thrust plate 52 approaches the sheet by a motor (not shown), projects between the first and second folds of the sheet, and pushes the sheet into the nip of the pair of folding rollers 53 (FIG. 6C). ). Since the thickness of the abutting plate 52 is the same as the distance between the first and second folds of the first to fifth sheets, the abutting plate 52 is caused by the pressure contact pressure (nip pressure) of the pair of folding rollers 53. The sheet can be folded in a U shape.

  It is necessary to push the pushing plate 52 into the nip until the portion of the back PW (FIG. 7) of the folded sheet passes through the nip of the folding roller pair 53. After the portion of the sheet that has become the back PW passes through the nip, the abutting plate 52 moves backward and comes out of the nip of the pair of folding rollers 53. If the thrust plate 52 moves backward from the nip before the portion of the sheet that has become the back PW of the sheet passes through the nip of the pair of folding rollers 53, the portion of the sheet that has become the back PW of the sheet becomes the pair of folding rollers 53. When crushed, the sheet cannot be folded into a U-shape. For this reason, the pushing plate 52 cannot be retracted until the portion of the back PW (FIG. 7) of the folded sheet passes through the nip of the pair of folding rollers 53.

  In this way, the sheet is formed into a U-shaped book with a flat back and a saddle stitch bookbinding (square saddle), and is discharged to the bookbinding tray 26 by the discharge roller pair 54 (FIG. 10 (S9, S10). )).

  In the above description, the sheet is fed into the stopper 28 first from the sheet that becomes the inner side when folded. For this reason, the space | interval of a 1st crease | fold and a 2nd crease | fold is extended gradually. However, when the sheet is fed to the stopper 28 first from the sheet that becomes the outer side when folded, and sequentially stacked on the veneer 52 side, the distance between the first fold line and the second fold line. May be narrowed sequentially.

  In the above description, the crease unit 4 is configured to make two creases on the sheet. In this case, the sheet is bound in a U shape. At this time, the thickness of the veneer 52 is preferably thinner than when the two creases are provided. Further, when the fold line is at one place, the saddle stitch stapler 32 needs to bind the center PC of the sheet, and the center part of the sheet is the back.

  One pair of creasing units is provided in the upper and lower sides, but only one of the upper and lower sides may be provided. In this case, the sheet can be folded only from one side by the creasing plate.

  As described above, the saddle stitch bookbinding apparatus 23 folds the sheet with the crease unit 4, flattens the creased portion with the control roller pair 31, and aligns the leading edge with the stopper 28. It has become. For this reason, when the sheets are bound by the saddle stitching stapler 32, the folds of the sheets can be aligned, and can be easily folded when the sheets are folded by the folding mechanism 33. As a result, it is possible to finish the bundled sheet into a book with a good appearance.

  Further, when the sheet can be bent easily by aligning the folds, it is possible to reduce the force by which the thrust plate 52 pushes the sheet and the nip pressure for the folding roller pair 53 to sandwich the sheet and bend it. it can. As a result, it is possible to reduce the size of the bending mechanism 33, save the driving force, and reduce the operation noise.

  P: sheet, NP: nip of control roller pair, PW: spine, 1: image forming apparatus, 1A: apparatus main body of the image forming apparatus, 2: sheet processing apparatus, 4: crease unit (crease unit), 6: Image forming apparatus, 20: leading edge detection sensor (detection means), 23: saddle stitch bookbinding apparatus, 28: stopper (alignment means), 31: control roller pair (conveying roller pair), 32: saddle stitch stapler (binding means), 33: bending mechanism, 34: CPU, 41U: upper crease part, 41D: lower crease part, 45U, 45D: crease plate (crease member), 51: needle, 52: thrust plate, 53: folding roller versus

Claims (9)

In the saddle stitch bookbinding device that binds and bends the middle part of the sheet,
A crease means for making a crease perpendicular to the sheet conveying direction in an intermediate portion of the sheet;
A pair of conveying rollers that conveys the sheet that has been creased by the crease unit;
An alignment means for aligning ends of the plurality of creased sheets conveyed by the conveyance roller pair in the sheet conveyance direction;
Binding means for binding an intermediate portion of the sheets aligned by the alignment means;
Folding means for folding the creased portion of the sheet,
The conveying roller pair flattens the creased portion while conveying the creased sheet.
A saddle stitch binding apparatus characterized by the above. The pair of conveying rollers can hold the sheet when the crease is creased by the crease unit with a nip pressure that stops rotation and does not cause a positional deviation of the sheet.
The saddle stitch bookbinding apparatus according to claim 1, wherein: The conveyance roller pair is a registration roller pair that receives the leading edge of the sheet before crease in a state where rotation is stopped, and corrects the skew of the sheet.
A saddle stitch bookbinding apparatus according to claim 1 or 2, The crease unit includes a crease member that folds the sheet in the thickness direction, the first crease is made by the crease member, and the sheet is transported by a predetermined distance by the pair of transport rollers. Crease,
The saddle stitch bookbinding apparatus according to any one of claims 1 to 3. The crease members are arranged in pairs, with the tips spaced apart from each other on both sides of the path through which the sheet passes, and crease the sheet by alternately protruding from both sides.
The saddle stitch bookbinding apparatus according to claim 4. The conveying roller pair is capable of changing a sheet conveying distance between the preceding sheet and the succeeding sheet between the time when the crease attaching unit makes the first crease and the time when the second crease is made, The crease forming means can change the distance between the first crease and the second crease by changing the distance.
A saddle stitch bookbinding apparatus according to claim 4 or 5, wherein Each roller of the conveying roller pair is one continuous roller.
A saddle stitch bookbinding apparatus according to any one of claims 1 to 6. A detection unit that detects that a portion of the sheet that is creased by the pair of conveyance rollers is conveyed to the crease unit;
A saddle stitch bookbinding apparatus according to any one of claims 1 to 7, Image forming means for forming an image on a sheet;
A saddle stitch bookbinding device according to any one of claims 1 to 8, wherein the sheet is processed;
The saddle stitch bookbinding device folds and aligns the sheet on which the image is formed by the image forming unit, aligns and binds, and folds the fold.
An image forming apparatus.

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