Abstract:
A sheet post-processing apparatus that performs a cutting process on a booklet formed by a bundle of center-folded sheets of paper includes: a conveying member that conveys the booklet; a leading edge stopper capable of reciprocating in a booklet conveying direction and used for setting a cutting position by abutting on a center-folded portion of the booklet; and a supporting member that supports the booklet when the cutting position of the booklet is to be set. When the booklet is being conveyed, the conveying member and the conveyed booklet are located in a contact position, and when the cutting position of the booklet is to be set, each of the conveying member and the conveyed booklet is located in one of separated positions, and the cutting position of the booklet is set by the leading edge stopper while the conveyed booklet is supported by the supporting member.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    The present application claims priority to and incorporates by reference the entire contents of Japanese Patent Application No. 2010-278927 filed in Japan on Dec. 15, 2010. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to a sheet post-processing apparatus used for cutting off an edge of a booklet produced by performing center folding in a process to bind sheets of paper, and an image forming apparatus and an image forming system that include the sheet post-processing apparatus. 
         [0004]    2. Description of the Related Art 
         [0005]    In the related art, in the field of printing, a sheet post-processing apparatus that includes a cutting device is practically used in which the cutting device cuts off an edge of a booklet that has passed through a saddle stitching process and a center folding process and performs edge alignment. In addition, recently, a sheet post-processing apparatus that includes a cutting device has been produced. The sheet post-processing apparatus receives sheets of paper with images thereon formed by an image forming apparatus such as a copying machine or a printer, performs a saddle stitching process and a center folding process, performs binding to produce, for example, a weekly magazine-like form, and allows the cutting device to cut off the edge of the booklet and to perform edge alignment. 
         [0006]    In the cutting device described above, a booklet that has been produced through a saddle stitching process and a center folding process is conveyed by a conveying unit such as a belt such that a folded portion of the booklet becomes a leading edge in a conveying direction. Then, the booklet is stopped by abutting on an abutting member, and pressed at a portion near the folded portion by a first pressing unit and a portion near the edge by a second pressing unit, respectively. In this state, the edge is cut off by the cutting device. As a method for setting a position of the booklet when cutting is to be performed in this kind of an apparatus, there is a known position setting method according to which the booklet is stopped when the folding portion of the booklet abuts on a leading edge stopper, the leading edge stopper is moved toward the folded portion of the booklet, and the position of the booklet is set while posture of the booklet is corrected. 
         [0007]    However, in the position setting method in the cutting device of the related art, there has been a problem in that the frictional force occurring between the conveying member and the booklet when the booklet slides on the conveying member is strong to cause defects such as cover peeling or an opposite arrangement between a right page and a left page when the booklet is opened after the edge has been cut off, thereby impairing the finishing quality of a sheet bundle. 
         [0008]    Japanese Patent Application Laid-open No. 2010-195582 discloses a center-folded booklet conveying apparatus having a simplified mechanical structure capable of setting a position of a saddle-stitched and center-folded booklet to a predetermined position by a simplified conveying operation. The center-folded booklet conveying apparatus includes a booklet conveying unit that conveys a booklet having a saddle-stitched and center-folded portion and made of a plurality of sheet members in a state where the booklet is stacked on a booklet stacking member and a booklet position setting unit having a booklet abutting member for abutting on the center-folded portion and capable of reciprocating in a booklet conveying direction. The booklet is stopped when the position of the center-folded portion of the booklet having been conveyed by the booklet conveying unit is set at a downstream side of a predetermined position in the booklet conveying direction, and thereafter, the abutting member is moved the downstream to an upstream side in the booklet conveying direction to abut on the center-folded portion and further to press center-folded portion backwards in the booklet conveying direction, thereby to set the position of the booklet to the predetermined position by sliding the booklet on the stacking member. 
         [0009]    However, the problems caused by the strong frictional force between the conveying member and the booklet have not been unresolved yet. That is, defects such as cover peeling or an opposite arrangement between a right page and a left page when the booklet is opened after the edge has been cut off deteriorates the finishing quality of a bundle of sheets. 
         [0010]    Therefore, there is a need to improve the quality of a booklet by retracting a conveying member with a large coefficient of friction when the position of the booklet in the cutting device is to be set, by reducing a frictional force associated with the conveyance of the booklet accomplished by letting the booklet slide on a different supporting member than the conveying member, and by achieving stability in conveying the booklet. 
       SUMMARY OF THE INVENTION 
       [0011]    It is an object of the present invention to at least partially solve the problems in the conventional technology. 
         [0012]    A sheet post-processing apparatus that performs a cutting process on a booklet formed by a bundle of center-folded sheets of paper includes: a conveying member that conveys the booklet; a leading edge stopper capable of reciprocating in a booklet conveying direction and used for setting a cutting position where the cutting process is to be performed by abutting on a center-folded portion of the booklet; and a supporting member that supports the booklet when the cutting position of the booklet is to be set. When the booklet is being conveyed, the conveying member and the conveyed booklet are located in a contact position where the conveying member and the conveyed books are in contact with each other, and when the cutting position of the booklet is to be set, each of the conveying member and the conveyed booklet is located in one of separated positions that are separated from each other, and the cutting position of the booklet is set by the leading edge stopper while the conveyed booklet is supported by the supporting member. 
         [0013]    An image forming apparatus includes a sheet post-processing apparatus that includes: a sheet cutting device that performs a cutting process on a booklet formed by a bundle of center-folded sheets of paper and that includes: a conveying member that conveys the booklet; a leading edge stopper capable of reciprocating in a booklet conveying direction and used for setting a cutting position where the cutting process is to be performed by abutting on a center-folded portion of the booklet; and a supporting member that supports the booklet when the cutting position of the booklet is to be set. When the booklet is being conveyed, the conveying member and the conveyed booklet are located in a contact position where the conveying member and the conveyed books are in contact with each other, and when the cutting position of the booklet is to be set, each of the conveying member and the conveyed booklet is located in one of separated positions that are separated from each other, and the cutting position of the booklet is set by the leading edge stopper while the conveyed booklet is supported by the supporting member. 
         [0014]    An image forming system includes a sheet post-processing apparatus that includes: a sheet cutting device that performs a cutting process on a booklet formed by a bundle of center-folded sheets of paper and that includes: a conveying member that conveys the booklet; a leading edge stopper capable of reciprocating in a booklet conveying direction and used for setting a cutting position where the cutting process is to be performed by abutting on a center-folded portion of the booklet; and a supporting member that supports the booklet when the cutting position of the booklet is to be set. When the booklet is being conveyed, the conveying member and the conveyed booklet are located in a contact position where the conveying member and the conveyed books are in contact with each other, and when the cutting position of the booklet is to be set, each of the conveying member and the conveyed booklet is located in one of separated positions that are separated from each other, and the cutting position of the booklet is set by the leading edge stopper while the conveyed booklet is supported by the supporting member. 
         [0015]    The above and other objects, features, advantages and technical and industrial significance of this invention will be better understood by reading the following detailed description of presently preferred embodiments of the invention, when considered in connection with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0016]      FIG. 1  is a schematic diagram illustrating a configuration of a sheet post-processing apparatus according to an embodiment of the present invention and a configuration of an image forming system that includes an image forming apparatus equipped with the sheet post-processing apparatus; 
           [0017]      FIG. 2  is a schematic diagram illustrating a mechanical configuration of a cutting device illustrated in  FIG. 1  and a saddle-stitching stacking tray attached to the cutting device; 
           [0018]      FIG. 3A  is a diagram illustrating an operation method for separating a booklet from a conveying member according to a first embodiment; 
           [0019]      FIG. 3B  is a diagram illustrating an operation method for separating the booklet from the conveying member according to the first embodiment; 
           [0020]      FIG. 3C  is a diagram illustrating an operation method for separating the booklet from the conveying member according to the first embodiment; 
           [0021]      FIG. 3D  is a diagram illustrating an operation method for separating the booklet from the conveying member according to the first embodiment; 
           [0022]      FIG. 4A  is a diagram illustrating an operation method for separating a booklet from a conveying member according to a second embodiment; 
           [0023]      FIG. 4B  is a diagram illustrating an operation method for separating the booklet from the conveying member according to the second embodiment; 
           [0024]      FIG. 4C  is a diagram illustrating an operation method for separating the booklet from the conveying member according to the second embodiment; 
           [0025]      FIG. 4D  is a diagram illustrating an operation method for separating the booklet from the conveying member according to the second embodiment; 
           [0026]      FIG. 5A  is a diagram illustrating an operation method for separating a booklet from a conveying member according to a third embodiment; 
           [0027]      FIG. 5B  is a diagram illustrating an operation method for separating the booklet from the conveying member according to the third embodiment; and 
           [0028]      FIG. 5C  is a diagram illustrating an operation method for separating the booklet from the conveying member according to the third embodiment. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0029]    In the present invention, a conveying member (belt) having a high frictional coefficient is separated from a booklet when a position of the booklet is set in a cutting device, and the booklet is made to be supported by and slide on a supporting member that has a low frictional coefficient, thereby to reduce a frictional force when the position of the booklet is to be set. Therefore, booklet conveyance is stably performed, and a quality of the booklet can be improved. That is, because the conveying member has functions of stopping and conveying the booklet with static friction, the conveying member has a high frictional coefficient. When the booklet is made to set a position by a sliding motion, the booklet is separated from the conveying member that has a high frictional coefficient, and the booklet is made to slide on the supporting member that has a low frictional coefficient, thereby the frictional force applied to the booklet is reduced and deformation of the booklet is decreased. 
       Embodiment 
       [0030]    First Embodiment 
         [0031]    A first embodiment will be described in detail with reference to the drawings. 
         [0032]      FIG. 1  is a schematic diagram illustrating a configuration of a sheet post-processing apparatus according to the embodiment and a configuration of an image forming system that includes an image forming apparatus equipped with the sheet post-processing apparatus. In  FIG. 1 , the image forming system according to the embodiment basically includes an image forming apparatus  1 , an inserter device  3 , a paper folding apparatus  6 , a binding apparatus  7 , a post-processing apparatus  9 , and a cutting apparatus  11 . 
         [0033]    In the embodiment, the image forming apparatus  1  is configured as a digital Multi-Function Peripheral (MFP) and includes an automatic document feeder (ADF)  2  and an operation panel  20  attached with a liquid crystal display  20   b.  The image forming apparatus  1  is connected to an inserter device  3  at a downstream side in a sheet conveying direction. 
         [0034]    The inserter device  3  has two sheet trays  4  and  5  and can insert a sheet on which an image has been formed or a sheet that cannot pass through the image forming apparatus  1  independently, before or after a sheet output from the image forming apparatus  1 , or between arbitrary sheets. A sheet folding apparatus  6  that can perform various kinds of folding such as Z folding or tri-folding is connected at the downstream of the inserter device  3 . 
         [0035]    In addition, a binding apparatus  7  is connected at the downstream of the sheet folding apparatus  6 . The binding apparatus  7  includes a binder such as a tape binder, a ring binder, or a glue binder. The booklet on which the binding has been performed is to be discharged on a binding tray  8 . 
         [0036]    In addition, the post-processing apparatus  9  is connected to a position in the downstream side of the sheet folding apparatus  6 . As described later, the post-processing apparatus (finisher)  9  includes a punching unit and a stapling unit capable of performing punching and staple binding, respectively. In addition, the post-processing apparatus  9  in the image forming system is also configured to have a function capable of producing a saddle-stitched booklet. Various well-known techniques may be employed to implement these functions. 
         [0037]    The sheet to which general discharging or edge binding by staple stitching is performed is discharged on a post-processing tray  10 , and the cutting apparatus  11  is connected to a position on the downstream side thereof. The cutting apparatus  11  has a function of receiving the booklet that is saddle-stitched by the post-processing apparatus  9  and cutting off and aligning the edge of the booklet. After cutting, the booklet is discharged on a stacking tray  12  to be stacked thereon. 
         [0038]      FIG. 2  is a schematic diagram illustrating a mechanical configuration of the cutting apparatus  11  and the stacking tray  12  attached to the cutting apparatus  11  according to the embodiment. In the image forming apparatus  1  illustrated in  FIG. 1 , sheets fed from a main body of the image forming apparatus  1  or the inserter device  3  are saddle-stitched and bound as a bundle of sheets by the post-processing apparatus  9 , so that a booklet  25  is formed. The booklet  25  is discharged from the post-processing apparatus  9  in the direction along which the back side (folded side) is set as a leading edge. The cutting apparatus  11  is provided to be adjacent to the post-processing apparatus  9  in the downstream side and receives the discharged saddle-stitched booklet  25 . 
         [0039]    The cutting apparatus  11  is configured to include a feeding unit  31 , a position setting unit  44 , a cutter unit  41 , and a tray unit  54 . The feeding unit  31  includes an inlet guide plate  32 , feeding guides  33  and  34 , a carrying-in sensor  35 , and a feeding side conveying motor  36 . The saddle-stitched booklet  25  is conveyed from the inlet guide plate  32  to the feeding unit  31  and conveyed by being interposed between the upper and lower feeding guides  33  and  34 . 
         [0040]    As for the feeding guides  33  and  34 , the upper feeding guide  34  is a belt having a circular cross-section, the lower feeding guide  33  is a flat belt, and the booklet  25  is conveyed by being interposed therebetween. In order to accept booklets  25  with various amounts of thickness, the upper feeding guide  34  can oscillate about a fulcrum provided at the inlet side, so that a gap between the upper and lower feeding guides  33  and  34  can be widened according to the thickness of the booklets  25 . 
         [0041]    The position setting unit  44  includes a conveying member  44   a,  an abutting member  44   b,  and a supporting member  44   c.  In addition, with respect to the driving of the elements, a position-setting side inlet roller pressing motor  45 , a position-setting side inlet roller pressing sensor  46 , a position-setting home position (HP) sensor  47 , an abutting member unit press motor  48 , an abutting member HP sensor  49 , an abutting member unit moving motor  50 , an abutting member unit sheet sensor  51 , a position-setting side carrying-out motor  52 , and a discharging sensor  53  are provided therein. 
         [0042]    The booklet  25  that has been conveyed from the feeding unit  31  is conveyed to the position setting unit  44 . The conveyed booklet  25  is stopped at a position downstream from a cutting position, and the booklet  25  is separated from the conveying member  44   a  and supported by the supporting member  44   c.  Next, the abutting member  44   b  abuts on the center-folded portion of the booklet  25  to make the booklet  25  slide to reach the cutting position, thereby performing position setting. In addition, after the position setting, the booklet  25  is pressed and flattened by using a press mechanism that includes the abutting member unit press motor  48  and the like to prepare for cutting. 
         [0043]    A cutter unit  41  is provided between the feeding unit  31  and the position setting unit  44 . A cutter type is so-called a guillotine type, where an upper blade is a movable blade that has an acute, shearing angle, and the lower blade is a fixed blade having an obtuse angle of about 90 degrees at an edge. The booklet  25  of which the cutting position has been set by the position setting unit  44  is cut by the operation in which the upper blade of the cutter unit  41  is driven by a cutter motor  42  to move down. In order to prevent deviation of a bundle of the sheets at the time of cutting, a press mechanism is provided for pressing the sheets. Before the upper blade moves down, the press mechanism strongly presses the booklet  25  at a portion near the cutting portion, and thereafter, the booklet  25  is cut by a downward motion of the upper blade. In addition, reference numeral  43  denotes a home position sensor for detecting a home position of the cutter. 
         [0044]    Cutting waste generated from the cutting operation by the cutter unit  41  falls by gravity to be inserted into a trash receptacle  37  provided below the cutting device. The trash receptacle  37  is provided with a sensor  38  for detecting whether or not the trash receptacle is full of the cutting waste and a sensor  39  for detecting whether a trash can is set. 
         [0045]    The tray unit  54  includes a discharging lever  55 , a first full-capacity sensor  56 , a second full-capacity sensor  57 , a remaining-sheet sensor  58 , and a tray conveying motor  59 . The pressing pressure is released from the booklet  25  which the edge has been cut, the conveying member  44   a  is returned from a booklet separating position to a booklet conveying position, thereby starting the conveying process. The booklet is conveyed to the discharging portion and discharged on the stacking tray  12  by a discharge roller (not shown). At this time, the abutting member  44   b  is brought into contact with the trailing edge of the booklet for assisting to discharge the booklet, so that the booklet is prevented from being not completely discharged with the trailing edge remaining in the apparatus. A pair of flat belts  24 , and a driving mechanism for driving the flat belts  24  are provided on the stacking tray  12  so that the conveyance of the booklet  25  and the adjustment of the stacked posture can be performed. Therefore, when the booklet  25  is discharged, the flat belts  24  are moved, so that the booklet  25  is conveyed little by little. 
         [0046]      FIGS. 3A to 3D  are diagrams illustrating an operation method of separating a booklet from a conveying member according to the embodiment. The position setting unit illustrated in  FIGS. 3A to 3D  includes a conveying member  44   a,  an abutting member  44   b,  and a supporting member  44   c.  In addition, with respect to the driving of the elements, a conveying member lifting motor  60 , a conveying member lifting mechanism  61 , an abutting member lifting motor  62 , an abutting member lifting mechanism  63 , an abutting member conveying direction moving motor  64 , and an abutting member conveying direction moving mechanism  65  are provided therein. 
         [0047]    As illustrated in  FIG. 3A , the booklet  25  on which the center folding process has been performed by the post-processing apparatus  9  is conveyed slightly downstream from the cutting position by the conveying member  44   a.  Next, the driving of the conveying member  44   a  is stopped, and as illustrated in  FIG. 3B , the conveying member  44   a  is lifted down until an upper surface of the conveying member  44   a  becomes lower than an upper surface of the supporting member  44   c  by the conveying member lifting motor  60  and the conveying member lifting mechanism  61 , and thereafter, the conveying member is stopped. Therefore, the booklet  25  becomes supported by the supporting member  44   c.  Next, as illustrated in  FIG. 3C , the abutting member  44   b  is lifted down to a position to be equal to or lower in height than a contact surface between the booklet  25  and the supporting member  44   c  by the abutting member lifting motor  62 . Next, as illustrated in  FIG. 3D , the abutting member  44   b  is moved to an upstream side in the conveying direction by the abutting member conveying direction moving motor  64  and the abutting member conveying direction moving mechanism  65  so as to abut on a center-folded surface of the booklet  25 , and the booklet  25  is further moved to the cutting position by maintaining sliding posture. Therefore, the position setting can be performed without sliding on the conveying member that has a high frictional coefficient, and it becomes possible to prevent cover peeling or an opposite arrangement between a right page and a left page when the booklet is opened after cutting off an edge ob the booklet  25 . Next, cutting is performed by the cutter unit  41 , and after the cutting, the conveying member  44   a  is returned from the separation position to the conveying position by the conveying member lifting motor  60  and the conveying member lifting mechanism  61 , and the conveyance is restarted. 
         [0048]    Second Embodiment 
         [0049]      FIGS. 4A to 4D  are diagrams illustrating an operation method for separating a booklet from a conveying member according to a second embodiment. In  FIG. 4 , the position setting unit includes a conveying member  44   a,  an abutting member  44   b,  and a supporting member  44   c.  In addition, with respect to the driving of the elements, a supporting member lifting motor  66 , a supporting member lifting mechanism  67 , an abutting member lifting motor  62 , an abutting member lifting mechanism  63 , an abutting member conveying direction moving motor  64 , and an abutting member conveying direction moving mechanism  65  are provided therein. 
         [0050]    As illustrated in  FIG. 4A , the booklet  25  on which the center folding process has been performed by the post-processing apparatus  9  is conveyed slightly downstream from the cutting position by the conveying member  44   a.  Next, the driving of the conveying member  44   a  is stopped, and as illustrated in  FIG. 4B , the supporting member  44   c  is moved up so that an upper surface of the supporting member  44   c  becomes higher than an upper surface of the conveying member  44   a  by the supporting member lifting motor  66  and the supporting member lifting mechanism  67 , and thereafter, the supporting member  44   c  is stopped. Because the upper surface of the supporting member  44   c  is moved up so as to be higher than the upper surface of the conveying member  44   a,  the booklet  25  is in the state that the booklet  25  is supported by the supporting member  44   c.  Next, as illustrated in  FIG. 4C , the abutting member  44   b  is lifted down to a position lower than a contact surface between the booklet  25  and the supporting member  44   c  by the abutting member lifting motor  62  and the abutting member lifting mechanism  63 . Next, as illustrated in  FIG. 4D , the abutting member  44   b  is moved to an upstream side in the conveying direction by the abutting member conveying direction moving motor  64  and the abutting member conveying direction moving mechanism  65  so as to abut on a center-folded surface of the booklet, and the booklet  25  is moved to a cutting position while sliding posture is maintained. Therefore, position setting can be performed without sliding on the conveying member  44   a  with high friction, so that it becomes possible to prevent cover peeling or an opposite arrangement between a right page and a left page when the booklet is opened after cutting off an edge ob the booklet  25 . Next, cutting is performed by the cutter unit  41 , and after the cutting, the supporting member  44   c  is returned from a booklet abutting position to a separation position by the supporting member lifting motor  66  and the supporting member lifting mechanism  67 , and conveyance of the conveying member  44   a  is restarted. 
         [0051]    Third Embodiment 
         [0052]      FIGS. 5A to 5C  are diagrams illustrating an operation method for separating a booklet from a conveying member according to a third embodiment. As illustrated in  FIG. 5A , after cutting the booklet, the booklet  25  is conveyed toward a discharging portion by the conveying member. When a leading edge of the booklet reaches a discharging roller, as illustrated in  FIG. 5B , an abutting member is lifted down to a conveying surface to abut a trailing edge of the booklet that is in a process of discharging. Next, as illustrated in  FIG. 5C , the trailing edge of the booklet discharged by the discharging roller is pushed by the abutting member to assist the discharging operation. Therefore, incomplete discharging of the booklet with the trailing edge remaining in the apparatus can be prevented. 
         [0053]    According to the embodiments, a frictional force associated with a position setting of a booklet in a cutting device can be reduced, and booklet conveyance is stably performed, thereby a quality of the booklet can be improved. 
         [0054]    Although the invention has been described with respect to specific embodiments for a complete and clear disclosure, the appended claims are not to be thus limited but are to be construed as embodying all modifications and alternative constructions that may occur to one skilled in the art that fairly fall within the basic teaching herein set forth.