Patent Publication Number: US-10322901-B2

Title: Sheet processing apparatus

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 15/094,385, filed on Apr. 8, 2016, which is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2015-115805, filed on Jun. 8, 2015, the entire contents of each of which are incorporated herein by reference. 
    
    
     FIELD 
     An embodiment described here generally relates to a sheet processing apparatus. 
     BACKGROUND 
     A post-processing apparatus that performs post-processing on sheets transported from an image-forming apparatus is known. The post-processing apparatus includes a processing tray and a standby tray. In the processing tray, post-processing is performed. The standby tray is provided above the processing tray. During the post-processing performed on sheets in the processing tray, the standby tray temporarily retains subsequent sheets. When the processing tray becomes empty, the standby tray drops the retained sheets toward the processing tray. Further, the post-processing apparatus includes a pressing mechanism that presses the sheets toward the processing tray when the sheets are moved from the standby tray to the processing tray. The pressing mechanism presses the sheets toward the processing tray and thus can quickly move the sheets from the standby tray to the processing tray. Incidentally, the sheets transported by the standby tray may have curls. In the case where the sheets have curls, depending on the configuration of the pressing mechanism, the sheets may be pushed out in an unintentional direction. If the sheets are pushed out in an unintentional direction, the movement of the sheets may be made unstable. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a front view showing an example of an overall configuration of an image-forming system according to an embodiment. 
         FIG. 2  is a block diagram showing an example of the overall configuration of the image-forming system shown in  FIG. 1 . 
         FIG. 3  is a cross-sectional view showing a configuration example of a post-processing apparatus according to the embodiment. 
         FIG. 4  is a perspective view showing a standby unit and a processing unit shown in  FIG. 3 . 
         FIG. 5  is a cross-sectional view showing the standby unit and the processing unit shown in  FIG. 3 . 
         FIG. 6  is a plan view showing a transport guide shown in  FIG. 5 . 
         FIG. 7  is a cross-sectional view of the transport guide taken along the line F 7 -F 7  shown in  FIG. 6 . 
         FIG. 8  is a cross-sectional view showing an operation of the post-processing apparatus according to the embodiment. 
         FIG. 9  is a cross-sectional view showing an operation of the post-processing apparatus according to the embodiment. 
         FIG. 10  is a cross-sectional view showing an operation of the post-processing apparatus according to the embodiment. 
         FIG. 11  is a cross-sectional view showing an operation of the post-processing apparatus according to the embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     According to one embodiment, a sheet processing apparatus includes a first tray, a second tray, and a pressing member. The first tray supports a transported sheet. The second tray is provided below the first tray and houses the sheet moved from the first tray. The pressing member includes a turning shaft, the turning shaft being located on a downstream side of a transport direction of the sheet relative to an end of an upstream side of the sheet supported in the first tray. When the sheet is moved from the first tray toward the second tray, the pressing member rotates about the turning shaft. The pressing member rotates about the turning shaft to press the sheet toward the second tray at a position on the upstream side relative to the turning shaft. 
     Hereinafter, a sheet processing apparatus of an embodiment will be described with reference to the drawings. It should be noted that in the following description, configurations having an identical or similar function are denoted by an identical reference symbol, and overlapping description thereof may be omitted. 
     A sheet processing apparatus of an embodiment will be described with reference to  FIGS. 1 to 11 . First,  FIG. 1  and each show an example of an overall configuration of an image-forming system  1 . The image-forming system  1  includes an image-forming apparatus  2  and a post-processing apparatus  3 . The image-forming apparatus  2  forms an image on sheet-like media such as paper (hereinafter, described as “sheets”). The post-processing apparatus  3  performs post-processing on the sheets transported from the image-forming apparatus  2 . The post-processing apparatus  3  is an example of a “sheet processing apparatus”. 
     The image-forming apparatus  2  includes a control panel  11 , a scanner  12 , a printer  13 , a paper feed unit  14 , a paper discharge unit  15 , and an image-forming control unit  16 . 
     The control panel  11  includes various keys that receive user&#39;s operations. For example, the control panel  11  receives an input on a type of post-processing performed on sheets. The control panel  11  transmits information on the input type of post-processing to the post-processing apparatus  3 . 
     The scanner  12  includes a read section that reads image information of an object to be duplicated. The scanner  12  transmits the read image information to the printer  13 . The printer  13  forms an output image (hereinafter, described as “toner image”) by a developer such as toner on the basis of the image information transmitted from the scanner  12  or an external device. The printer  13  transfers the toner image onto a surface of a sheet. The printer  13  applies heat and pressure to the toner image transferred onto the sheet, to fix the toner image onto the sheet. 
     The paper feed unit  14  supplies sheets to the printer  13  one by one at a timing at which the printer  13  forms a toner image. The paper discharge unit  15  transports the sheets, which are discharged from the printer  13 , to the post-processing apparatus  3 . 
     The image-forming control unit  16  controls an overall operation of the image-forming apparatus  2 . In other words, the image-forming control unit  16  controls the control panel  11 , the scanner  12 , the printer  13 , the paper feed unit  14 , and the paper discharge unit  15 . The image-forming control unit  16  is a control circuit including a CPU (Central Processing Unit), a ROM (Read Only Memory), and a RAM (Random Access Memory), for example. 
     Next, the post-processing apparatus (sheet processing apparatus)  3  will be described. First, an overall configuration of the post-processing apparatus  3  will be described. As shown in  FIG. 1 , the post-processing apparatus  3  is disposed adjacently to the image-forming apparatus  2 . The post-processing apparatus  3  executes post-processing on sheets transported from the image-forming apparatus  2 , the post-processing being specified through the control panel  11 . The post-processing includes stapling processing or sorting processing, for example. The post-processing apparatus  3  includes a standby unit  21 , a processing unit  22 , a discharge unit  23 , and a post-processing control unit  24 . 
     The standby unit  21  temporarily retains (buffers) sheets S (see  FIG. 3 ) transported from the image-forming apparatus  2 . For example, the standby unit  21  keeps subsequent sheets S waiting during post-processing performed on preceding sheets S in the processing unit  22 . The standby unit  21  is provided above the processing unit  22 . When the processing unit  22  becomes empty, the standby unit  21  drops the retained sheets S toward the processing unit  22 . 
     The processing unit  22  performs post-processing on the sheets S. For example, the processing unit  22  aligns the sheets S. The processing unit  22  performs stapling processing on the aligned sheets S. As a result, the sheets S are bound together. The processing unit  22  discharges the sheets S, which are subjected to the post-processing, to the discharge unit  23 . 
     The discharge unit  23  includes a fixed tray  23   a  and a movable tray  23   b . The fixed tray  23   a  is provided to an upper portion of the post-processing apparatus  3 . The movable tray  23   b  is provided to a side portion of the post-processing apparatus  3 . The fixed tray  23   a  and the movable tray  23   b  hold the sheets S that are subjected to the sorting processing and then discharged, for example. 
     The post-processing control unit  24  controls an overall operation of the post-processing apparatus  3 . In other words, the post-processing control unit  24  controls the standby unit  21 , the processing unit  22 , and the discharge unit  23 . 
     Further, as shown in  FIG. 2 , the post-processing control unit  24  controls an inlet roller  32   a , an outlet roller  33   a , a paddle unit  34 , and a drive mechanism  90 , which will be described later. The post-processing control unit  24  is a control circuit including a CPU, a ROM, and a RAM, for example. 
     Next, configurations of the sections of the post-processing apparatus  3  will be described in detail. It should be noted that in description on the following embodiment, a “sheet transport direction” means a transport direction D of the sheets S to a standby tray  41  of the standby unit  21  (entry direction of the sheets S to the standby tray  41 ). Further, in the description on the following embodiment, an “upstream side” and a “downstream side” mean an upstream side and a downstream side in the sheet transport direction D, respectively. Further, in the description on the following embodiment, a “front end” and a “rear end” mean an “end of the downstream side” and an “end of the upstream side” in the sheet transport direction D, respectively. Additionally, in the description on the following embodiment, a direction that is substantially parallel to an upper surface (transport surface)  45   b  of the standby tray  41  and is substantially orthogonal to the sheet transport direction D is described as a sheet width direction W. 
       FIG. 3  schematically shows a configuration of the post-processing apparatus  3 . As shown in  FIG. 3 , the post-processing apparatus  3  includes a transport path  31  for the sheets S, a pair of inlet rollers  32   a  and  32   b , a pair of outlet rollers  33   a  and  33   b , the standby unit  21 , the paddle unit  34 , and the processing unit  22 . 
     The transport path  31  is provided inside the post-processing apparatus  3 . The transport path  31  includes a sheet supply port  31   p  and a sheet discharge port  31   d . The sheet supply port  31   p  faces the image-forming apparatus  2 . The sheets S are supplied from the image-forming apparatus  2  to the sheet supply port  31   p . Meanwhile, the sheet discharge port  31   d  is located near the standby unit  21 . The sheets S that have passed through the transport path  31  are discharged from the sheet discharge port  31   d  to the standby unit  21 . 
     The inlet rollers  32   a  and  32   b  are provided near the sheet supply port  31   p . The inlet rollers  32   a  and  32   b  transport the sheets S, which have been supplied to the sheet supply port  31   p , toward the downstream side of the transport path  31 . For example, the inlet rollers  32   a  and  32   b  transport the sheets S, which have been supplied to the sheet supply port  31   p , to the outlet rollers  33   a  and  33   b.    
     The outlet rollers  33   a  and  33   b  are provided near the sheet discharge port  31   d . The outlet rollers  33   a  and  33   b  receive the sheets S transported by the inlet rollers  32   a  and  32   b . The outlet rollers  33   a  and  33   b  transport the sheets S from the sheet discharge port  31   d  to the standby unit  21 . 
     Next, the standby unit  21  will be described. The standby unit  21  includes the standby tray (buffer tray)  41 , an opening and closing drive unit  42  (see  FIG. 4 ), a transport guide  43 , and discharge rollers  44   a  and  44   b.    
     The standby tray  41  is an example of a “first tray”. The rear end of the standby tray  41  is located near the outlet rollers  33   a  and  33   b . The rear end of the standby tray  41  is located to be slightly lower than the sheet discharge port  31   d  of the transport path  31 . The standby tray  41  is tilted with respect to a horizontal direction so as to gradually increase in height toward the downstream side of the sheet transport direction D. During post-processing performed on preceding sheets in the processing unit  22 , the standby tray holds subsequent sheets S in an overlapping manner in order to keep the subsequent sheets S waiting. 
     The standby tray  41  includes a bottom wall  45  and side walls (not shown). The bottom wall  45  includes a lower surface  45   a  and the upper surface (transport surface)  45   b . The bottom wall  45  supports the sheets S from below. The side walls support side portions of the sheets S in the sheet width direction W. 
     The bottom wall  45  will be specifically described. For example, the lower surface  45   a  of the bottom wall  45  is formed in a substantially flat surface. Meanwhile, the upper surface  45   b  of the bottom wall  45  includes a first area  45   ba  and a second area  45   bb . The first area  45   ba  is provided adjacently to the rear end of the standby tray  41 . The first area  45   ba  is tilted with respect to the lower surface  45   a  so as to gradually increase a distance from the lower surface  45   a  toward the downstream side of the sheet transport direction D. Meanwhile, the second area  45   bb  is provided between a front end of the standby tray  41  and the first area  45   ba . The second area  45   bb  has a fixed distance from the lower surface  45   a  or a reduced distance from the lower surface  45   a  even toward the downstream side of the sheet transport direction D. The upper surface  45   b  includes a boundary portion  45   bc  between the first area  45   ba  and the second area  45   bb . The bottom wall  45  has the maximum thickness in the boundary portion  45   bc.    
       FIG. 4  schematically shows the standby tray  41 . As shown in  FIG. 4 , the standby tray  41  includes a first tray member  46   a  and a second tray member  46   b . The first tray member  46   a  and the second tray member  46   b  are separated from each other in the sheet width direction W. The first tray member  46   a  and the second tray member  46   b  are movable in a mutually approaching direction and a mutually separating direction. 
     The opening and closing drive unit  42  can drive the first tray member  46   a  and the second tray member  46   b  in the mutually approaching direction and the mutually separating direction. In the case where the sheets S wait in the standby tray  41 , the opening and closing drive unit  42  drives the first tray member  46   a  and the second tray member  46   b  so as to approach each other. As a result, the sheets S are supported by the first tray member  46   a  and the second tray member  46   b . Meanwhile, in the case where the sheets S are moved from the standby tray  41  toward a processing tray  61  of the processing unit  22 , the opening and closing drive unit  42  drives the first tray member  46   a  and the second tray member  46   b  so as to separate from each other. As a result, the sheets S supported by the standby tray  41  drop toward the processing tray  61  from a gap between the first tray member  46   a  and the second tray member  46   b . As a result, the sheets S are moved from the standby tray  41  to the processing tray  61 . 
     The transport guide  43  (assist guide) is an example of a “first member (first pressing member, first biasing member)”. As shown in  FIG. 3 , the transport guide  43  is provided above the standby tray  41 . For example, the transport guide  43  has a length substantially equal to or larger than the half length of the standby tray  41  in the sheet transport direction D. In this embodiment, the transport guide  43  has substantially the same length as the standby tray  41  in the sheet transport direction D. The transport guide  43  is a plate-like member extending over the standby tray  41  (see  FIG. 6 ). The sheets S discharged from the outlet rollers  33   a  and  33   b  enter a gap between the transport guide  43  and the standby tray  41 . The sheets S that have entered the standby unit  21  are guided by the transport guide  43  and the standby tray  41  and proceed toward the depth of the standby unit  21 . It should be noted that the transport guide  43  will be described later in detail. 
     As shown in  FIG. 3 , the discharge rollers  44   a  and  44   b  are provided near the front end of the standby tray  41 . In the case where the sheets S are directly discharged from the standby tray  41  to the discharge unit  23 , the discharge rollers  44   a  and  44   b  transport the sheets S toward the movable tray  23   b  of the discharge unit  23 . 
     Next, the paddle unit  34  will be described. As shown in  FIG. 3 , the paddle unit  34  is provided between the standby tray  41  and the processing tray  61 . In other words, the paddle unit  34  is provided below the standby tray  41 . In the case where the sheets S are moved from the standby tray  41  toward the processing tray  61 , the paddle unit  34  rotates and thus presses the sheets S toward the processing tray  61 . Additionally, the paddle unit  34  moves the sheets S, which have dropped on the processing tray  61 , toward a stapler  62  that will be described later. Specifically, the paddle unit  34  includes a rotating shaft  49 , a rotating body  50 , first paddles  51 , and second paddles  52 . 
     The rotating shaft  49  is the center of rotation of the rotating body  50  of the paddle unit  34 . The rotating shaft  49  is located below the standby tray  41 . The rotating shaft  49  extends in the sheet width direction W. The paddle unit  34  is rotated about the rotating shaft  49  in a direction of an arrow A in  FIG. 3 . The rotating body  50  is cylindrically formed. The rotating body  50  is rotated about the rotating shaft  49 . The rotating body  50  is provided with the first paddles  51  and the second paddles  52 . 
     The first paddles  51  and the second paddles  52  protrude from the rotating body  50  in a radial direction of the rotating body  50 . The first paddles  51  and the second paddles  52  are each formed of an elastic member such as rubber. For example, the first paddles  51  are rotated at a timing at which the sheets S are moved from the standby tray  41  toward the processing tray  61 , to press the sheets S toward the processing tray  61 . As a result, also in the case where the sheets S stick to the transport guide  43 , the sheets S are reliably removed from the transport guide  43 . 
     The second paddles  52  are located behind the respective first paddles  51  in the rotation direction of the rotating body  50  of the paddle unit  34 . The length of each second paddle  52  is larger than that of each first paddle  51  in the radial direction of the rotating body  50 . The second paddles  52  are rotated to come into contact with the upper surface of a sheet S, which is located in the uppermost position in the sheets S that have dropped on the processing tray  61 . The second paddles  52  are further rotated in the state of being in contact with the upper surface of the sheet S, and thus moves the sheets S toward the stapler  62 . It should be noted that a detailed operation of the paddle unit  34  will be described later. 
     Next, the processing unit  22  will be described. The processing unit  22  includes the processing tray  61 , the stapler  62 , transport rollers  63   a  and  63   b , and a transport belt  64 . 
     The processing tray  61  is an example of a “second tray”. The processing tray  61  is provided below the standby tray  41 . The processing tray  61  is tilted with respect to the horizontal direction so as to gradually increase in height toward the downstream side of the sheet transport direction D. For example, the processing tray  61  is tilted substantially parallel to the standby tray  41 . The processing tray  61  aligns the sheets S, which have been moved from the standby tray  41 , in the sheet width direction W and the sheet transport direction D by an alignment plate or the like. 
     The stapler  62  is provided to an end of the processing tray  61 . The stapler  62  performs stapling (binding) processing on a batch of a predetermined number of sheets S located on the processing tray  61 . 
     The transport rollers  63   a  and  63   b  are disposed with a predetermined interval therebetween in the sheet transport direction D. The transport belt  64  is stretched over the transport rollers  63   a  and  63   b . The transport belt  64  is rotated in synchronization with the transport rollers  63   a  and  63   b . The transport belt  64  transports the sheets S between the stapler  62  and the discharge unit  23 . 
     Next, the transport guide  43  and the paddle unit  34  will be described in detail.  FIG. 5  shows the transport guide  43  in an enlarged manner. The transport guide  43  of this embodiment has a function of pressing (biasing) the sheets S toward the processing tray  61  in the case where the sheets S are moved from the standby tray  41  toward the processing tray  61 . Specifically, the transport guide  43  is movable between a standby position (see  FIG. 8 ) and a protruding position (see  FIG. 9 ). The standby position is an example of a “first position”. In the standby position, the whole of the transport guide  43  is located above the standby tray  41  and faces the standby tray  41 . Additionally, in the standby position, the transport guide  43  guides the transported sheets S to the standby tray  41 . In other words, the standby position is a guide position at which the transport guide  43  guides the sheets S. The protruding position is an example of a “second position”. In the protruding position, at least a part of the transport guide  43  protrudes downward below the lower surface  45   a  of the standby tray  41 . In the case where the sheets S are moved from the standby tray  41  toward the processing tray  61 , the transport guide  43  can press the sheets S toward the processing tray  61  by moving from the standby position to the protruding position. 
     Specifically, as shown in  FIG. 5 , the transport guide  43  includes a first end  43   a  and a second end  43   b  in the sheet transport direction D. The first end  43   a  is an end of the downstream side in the sheet transport direction D. The second end  43   b  is an end of the upstream side in the sheet transport direction D. 
     The first end  43   a  includes a turning shaft  81 . The turning shaft  81  is a pivot point of turn (center of turn) of the transport guide  43 . The turning shaft  81  of this embodiment is provided at substantially the same position as the front end of the standby tray  41  in the sheet transport direction D. Thus, the turning shaft  81  is located on the downstream side of the sheet transport direction D relative to a rear end Sa (see  FIG. 8 ) of the sheets S housed in the standby tray  41 . In this embodiment, the turning shaft  81  is disposed near the discharge roller  44   a  located above the standby tray  41 . Further, from a different perspective, the turning shaft  81  is located on the downstream side of the sheet transport direction D relative to the boundary portion  45   bc  (portion having the maximum thickness) of the upper surface  45   b  of the standby tray  41 . Additionally, from a different perspective, the turning shaft  81  is located on the downstream side of the sheet transport direction D relative to a drive member  91  that will be described later. 
     The second end  43   b  includes a pressing portion  82  that comes into contact with the sheets S. In this embodiment, the pressing portion  82  is located on the upstream side of the sheet transport direction D relative to the turning shaft  81 . In the case where the sheets S are moved from the standby tray  41  toward the processing tray  61 , the transport guide  43  is rotated about the turning shaft  81 , so that the pressing portion  82  presses the sheets S toward the processing tray  61  at the position on the upstream side relative to the turning shaft  81 . 
     As shown in  FIG. 5 , the pressing portion  82  is located near the sheet discharge port  31   d  of the transport path  31 . For example, the pressing portion  82  overlaps with at least a part of the rotating shaft  49  of the paddle unit  34  in a vertical direction (see a virtual line L 0  in  FIG. 5 ). In this embodiment, the pressing portion  82  extends to a position close to the sheet discharge port  31   d  beyond the virtual line L 0  passing through the rotating shaft  49  of the paddle unit in the vertical direction. In this embodiment, the pressing portion  82  is located above the rear end Sa of the sheets S housed in the standby tray  41  (see  FIG. 8 ). The pressing portion  82  presses the rear end Sa of the sheets S toward the processing tray  61 . The pressing portion  82  presses the rear end Sa of the sheets S at a position that is as close to a rear edge Se of the sheets S as possible. For example, the pressing portion  82  presses an area located at a distance of less than 20 mm from the rear edge Se of the sheets S. 
     For example, the pressing portion  82  descends to a position aligned with at least a part of the rotating shaft of the paddle unit  34  in a direction substantially parallel to an upper surface  61   a  of the processing tray  61  (see a virtual line L 1  in  FIG. 9 ). In other words, the pressing portion  82  presses the rear end Sa of the sheets S to a position aligned with at least a part of the rotating shaft  49  of the paddle unit  34  in the direction substantially parallel to the upper surface  61   a  of the processing tray  61 . It should be noted that the upper surface  61   a  of the processing tray  61  is an example of a “sheet placing surface” on which the sheets S are placed. 
     Further, from a different perspective, the pressing portion  82  descends to a position lower than a base  54  of at least one of the paddles  51  and  52  in the direction substantially parallel to the upper surface  61   a  of the processing tray  61 . It should be noted that the base  54  of each of the paddles  51  and  52  is a boundary portion between each of the paddles  51  and  52  and the rotating body  50 . In other words, the pressing portion  82  descends to a position lower than an upper end of the rotating body  50  (see a virtual line L 2  in  FIG. 9 ) in the direction substantially parallel to the upper surface  61   a  of the processing tray  61 . 
       FIG. 6  is a top view of the transport guide  43 . The width of the second end  43   b  in the sheet width direction W is larger than the width of the first end  43   a  in the sheet width direction W. For example, the second end  43   b  has a width that is sufficient to cover the rear end of the sheets S having various standards (for example, postcard size, B5 size, and A4 size). 
     Here, as shown in  FIG. 6 , the paddle unit  34  includes the first paddles  51  and the second paddles  52 . The first paddles  51  are provided to be separated from one another in the sheet width direction W. Similarly, the second paddles  52  are provided to be separated from one another in the sheet width direction W. For example, the first and second paddles  51  and  52  are disposed separately at positions corresponding to both ends of the sheets S having the various standards in the sheet width direction W. 
     As shown in  FIG. 6 , the second end  43   b  is provided with notches  83 . The notches  83  are provided separately from one another in the sheet width direction W. The notches  83  are provided at positions corresponding to the first and second paddles  51  and  52 . Each notch  83  extends from a rear edge of the second end  43   b  in the sheet transport direction D. The first and second paddles  51  and  52  pass through the notches  83  respectively corresponding thereto, and thus can rotate without interfering with the transport guide  43 . In other words, the transport guide  43  and the first and second paddles  51  and  52  have a pectinate shape. 
     As shown in  FIG. 6 , the transport guide  43  of this embodiment extends to the upstream side of the sheet transport direction D beyond at least a part of the rotation trajectories (rotation pathways) of the first paddles  51  and the second paddles  52 . Thus, the transport guide  43  of this embodiment can press the rear edge Se of the sheets S or a portion close to the rear edge Se of the sheets S toward the processing tray  61 . 
     The first paddles  51  of this embodiment pass through the notches  83 , and thus can press the sheets S being pressed by the transport guide  43 . In other words, the first paddles  51  can press the rear end Sa of the sheets S more downward in the state where the transport guide  43  is pressing the rear end Sa of the sheets S downward. 
     Next, the shape of the notch  83  will be described in detail. As shown in  FIG. 6 , each notch  83  includes a first tilted surface  83   a  that is tilted with respect to the sheet transport direction D. With the first tilted surface  83   a , the width of the notch  83  in the sheet width direction W is gradually reduced toward the downstream side of the sheet transport direction D. When the first tilted surface  83   a  is provided, the sheets S that have entered the notch  83  are guided by the first tilted surface  83   a , and thus are easy to come out of the notch  83 . 
       FIG. 7  is a cross-sectional view of the transport guide  43  taken along the line F 7 -F 7  shown in  FIG. 6 . As shown in  FIG. 7 , the transport guide  43  includes an upper surface  43   f , a lower surface  43   g , and a second tilted surface  43   h . The second tilted surface  43   h  is provided to the rear end of the transport guide  43 . The second tilted surface  43   h  is provided between the upper surface  43   f  and the lower surface  43   g . The second tilted surface  43   h  is tilted so as to approach the lower surface  43   g  toward the downstream side of the sheet transport direction D. The second tilted surface  43   h  is provided to both the notches  83  and portions excluding the notches  83 , in the transport guide  43 . When the second tilted surface  43   h  as described above is provided, the sheets S being in contact with the transport guide  43  are guided by the second tilted surface  43   h  and thus are easy to orient to a gap between the transport guide  43  and the standby tray  41 . 
     Next, the drive mechanism  90  that drives the transport guide  43  will be described. As shown in  FIG. 5 , the drive mechanism  90  includes the drive member  91 , a drive source  92  (see  FIG. 6 ), a driving force transmission mechanism  93  (see  FIG. 6 ), and a spring  94 . 
     The drive member  91  is a member to move the transport guide  43  from the standby position to the protruding position. As shown in  FIG. 5 , for example, the drive member  91  is a cam. The drive member  91  has the center of rotation C located above the standby tray  41 . The drive member  91  is a cam having an outer circumferential surface that is eccentric relative to the center of rotation C. The drive member  91  comes into contact with the upper surface  43   f  of the transport guide  43  by being rotated about the center of rotation C. The drive member  91  presses the transport guide  43  downward by being further rotated in a state of being in contact with the upper surface  43   f  of the transport guide  43 . As a result, the drive member  91  moves the transport guide  43  from the standby position toward the protruding position. As shown in  FIG. 6 , the drive member  91  is connected to the drive source  92  via the driving force transmission mechanism  93 . The drive source  92  is a motor, for example. The drive source  92  rotates the drive member  91  via the driving force transmission mechanism  93 . 
     As shown in  FIG. 5 , the spring  94  is provided on the upper side of the transport guide  43 . The spring  94  biases the transport guide  43  upward. Thus, the transport guide  43  that has moved to the protruding position returns to the standby position by the biasing force of the spring  94 , when depression by the drive member  91  is released. 
     Next, an operation flow in which the sheets S are dropped from the standby tray  41  toward the processing tray  61  will be described.  FIG. 8  shows a state where the sheets S enter the standby tray  41 . In the case where the sheets S enter the standby tray  41 , the transport guide  43  is located above the standby tray  41 . The sheets S are transported to the depth of the standby tray  41  by being guided by the standby tray  41  and the transport guide  43 . 
       FIG. 9  shows a state where the sheets S are moved from the standby tray  41  toward the processing tray  61 . In the case where the sheets S are moved from the standby tray  41  toward the processing tray  61 , the post-processing control unit  24  controls the drive of the drive source  92  to rotate the drive member  91 . When the drive member  91  rotates, the transport guide  43  is pressed downward. 
     The transport guide  43  pressed downward rotates about the turning shaft  81 , and thus presses the rear end Sa of the sheets S toward the processing tray  61 . The transport guide of this embodiment presses the sheets S toward the processing tray  61  at a position on the upstream side of the sheet transport direction D relative to the turning shaft  81 . 
     Additionally, the post-processing control unit  24  rotates the paddle unit  34  in a state where the transport guide  43  is pressing the sheets S. In other words, the post-processing control unit  24  rotates the paddle unit  34  in a state where at least a part of the transport guide  43  protrudes downward below the standby tray  41 . For example, the paddle unit  34  is rotated such that the first paddles  51  pass through the notches  83  in a state where the transport guide  43  is moved to the lowermost position. As a result, the first paddles  51  press the rear end Sa of the sheets S being pressed by the transport guide  43 . 
     When the paddle unit  34  is rotated in a state where the transport guide  43  is pressing the sheets S, a contact direction T of the first paddles  51  with respect to the sheets S is unlikely to be oriented in the opposite direction to the stapler  62 . For example, the first paddles  51  press the sheets S in a state where the transport guide  43  descends to a position aligned with the rotating shaft  49  of the paddle unit  34  in a direction substantially parallel to the upper surface  61   a  of the processing tray  61 . When the first paddles  51  press the sheets S in such a manner, the contact direction T of the first paddles  51  with respect to the sheets S is substantially orthogonal to the upper surface  61   a  of the processing tray  61 . Thus, it is possible to prevent the sheets S from being pressed by the paddle unit  34  toward the opposite direction to the stapler  62 . 
       FIG. 10  shows a state immediately after the first paddles  51  press the sheets S. As shown in  FIG. 10 , the first paddles  51  come into contact with the falling sheets S while rotating about the rotating shaft  49 . As a result, the first paddles  51  causes a force oriented to the stapler  62  to act on the falling sheets S. 
       FIG. 11  shows a state where the sheets S on the processing tray  61  are transported toward the stapler  62 . As shown in  FIG. 11 , the second paddles  52  of the paddle unit  34  are rotated with respect to the sheets S that have dropped on the processing tray  61 . As a result, the sheets S on the processing tray  61  are transported toward the stapler  62  by the second paddles  52 . Further, in this case, the transport rollers  63   a  and  63   b  and the transport belt  64  of the processing tray  61  are driven to transport the sheets S toward the stapler  62 . As a result, the sheets S on the processing tray  61  are transported toward the stapler  62 . 
     According to the post-processing apparatus  3  having the configuration as described above, the stability of movement of the sheets S can be improved. 
     Here, for the purpose of comparison, a pressing mechanism will be conceived, in which a pressing portion that presses the sheets S is located on the downstream side of the sheet transport direction D with respect to the turning shaft. In such a configuration, the turning shaft of the pressing mechanism is likely to be located above the rear end Sa of the sheets S, which are housed in the standby tray  41 , in the sheet transport direction D. Thus, the pressing portion of the pressing mechanism is likely to be located above a portion on the downstream side of the sheet transport direction D relative to the rear end Sa of the sheets S. For that reason, in the pressing portion of the pressing mechanism, it is difficult to press a portion close to the rear edge Se of the rear end Sa of the sheets S. 
     Here, as shown in  FIG. 8 , the rear end Sa of the sheets S may have an upward curl Ca. For example, the rear end Sa of the sheets S may have a relatively large curl Ca. In the case where the sheets S have such a curl Ca, in the pressing mechanism of the comparative example described above, it is difficult to press a portion close to the rear edge Se of the sheets S. Thus, it is difficult to appropriately press the curl Ca. When the rear end Sa of the sheets S is hit by the paddle unit  34  in a state where the curl Ca is hard to press appropriately, the paddle unit  34  comes into contact with the sheets S at a relatively higher position than the case where the sheets S do not have the curl Ca. When the paddle unit  34  comes into contact with the sheets S at a relatively higher position, a contact direction of the paddle unit  34  with respect to the sheets S is likely to be oriented in the opposite direction to the stapler  62 . Thus, in the case where the sheets S have the curl Ca, the paddle unit  34  may push out the sheets S in the opposite direction to the stapler  62 . When the sheets S are pushed out in the opposite direction to the stapler  62 , the movement of the sheets S becomes unstable. Additionally, the time necessary to transport the sheets S, which have dropped on the processing tray  61 , to the stapler  62  is increased. 
     Further, the post-processing apparatus  3  is demanded to achieve high-speed processing. Here, if a drop between the sheet discharge port  31   d  of the transport path  31  and the standby tray  41  is large, a certain period of time is necessary in order to move the sheets S from the transport path  31  to the standby tray  41 . Further, if a drop between the sheet discharge port  31   d  of the transport path  31  and the standby tray  41  is large, the curl Ca of the sheets S housed in the standby tray  41  may become large. If the curl Ca of the sheets S becomes large, the transport of subsequent sheets S may be inhibited. 
     In this regard, in the post-processing apparatus  3  of this embodiment, in order to reduce a drop between the sheet discharge port  31   d  of the transport path  31  and the standby tray  41 , the standby tray  41  is disposed to be slightly lower than the sheet discharge port  31   d . According to such a configuration, it is possible to shorten the time to move the sheets S from the transport path  31  to the standby tray  41 . As a result, it is possible to achieve speed-up of the post-processing apparatus  3 . Further, according to the configuration described above, a gap between the standby tray  41  and the transport guide  43  is relatively reduced. Thus, it is possible to prevent the curl Ca of the sheets S housed in the standby tray  41  from becoming large. 
     However, according to the configuration described above, the standby tray  41  is disposed at a relatively higher position than the paddle unit  34 . So, in the case where the sheets S have the curl Ca, the paddle unit  34  may come into contact with the sheets S at a relatively higher position. In other words, the sheets S are highly likely to be pushed out in the opposite direction to the stapler  62 . 
     In this regard, the post-processing apparatus  3  of this embodiment includes the standby tray  41 , the processing tray  61 , and the transport guide  43 . The processing tray  61  is provided below the standby tray  41 . The transport guide  43  includes the turning shaft  81 . The turning shaft  81  is located on the downstream side of the sheet transport direction D relative to the rear end Sa of the sheets S housed in the standby tray  41 . In the case where the sheets S are moved from the standby tray  41  toward the processing tray  61 , the transport guide  43  rotates about the turning shaft  81 , and thus presses the sheets S toward the processing tray  61  at a position on the upstream side relative to the turning shaft  81 . 
     According to such a configuration, the pressing portion  82  of the transport guide  43  can be disposed above the rear end Sa of the sheets S. Thus, it is possible to press the rear end Sa of the sheets S by the pressing portion  82  of the transport guide  43 . Thus, even in the case where the sheets S have a relatively large curl Ca, the pressing portion  82  of the transport guide  43  can appropriately press the curl Ca of the sheets S. Thus, in the case where the sheets S are moved from the standby tray  41  toward the processing tray  61 , a possibility that the paddle unit  34  comes into contact with the sheets S at a relatively higher position can be reduced. In other words, it is possible to prevent the sheets S from being pushed out in the opposite direction to the stapler  62 . As a result, the stability of movement of the sheets S can be improved. 
     In this embodiment, the transport guide  43  is movable between a first position at which the transport guide  43  is located above the standby tray  41  and a second position at which the transport guide  43  protrudes downward below the standby tray  41 . 
     According to such a configuration, the sheets S can be reliably guided to a position lower than the standby tray  41  by the transport guide  43 . As a result, a possibility that the paddle unit  34  comes into contact with the sheets S at a relatively higher position can be further reduced. As a result, the stability of movement of the sheets S can be further improved. 
     In this embodiment, the post-processing apparatus  3  includes the paddle unit  34 . The paddle unit  34  is provided below the standby tray  41 . In the case where the sheets S are moved from the standby tray  41  toward the processing tray  61 , the paddle unit  34  presses the sheets S toward the processing tray  61 . The paddle unit  34  rotates in a state where at least a part of the transport guide  43  protrudes downward below the processing tray  61 . As a result, the paddle unit  34  presses the sheets S toward the processing tray  61  in a state where at least a part of the transport guide  43  protrudes downward below the processing tray  61 . 
     According to such a configuration, the paddle unit  34  can press the sheets S more downward in a state where the sheets S are pressed by the transport guide  43 . In other words, even in the case where the sheets S have the curl Ca, the paddle unit  34  can press the sheets S in a state where the curl Ca is pressed by the transport guide  43 . Thus, it is possible to further reduce a possibility that the paddle unit comes into contact with the sheets S at a relatively higher position. As a result, the stability of movement of the sheets S can be further improved. 
     For example, the paddle unit  34  is driven to press the sheets S at a timing at which the transport guide  43  reaches the lowermost position. However, a timing at which the paddle unit  34  presses the sheets S is not limited to the above example. For example, the paddle unit  34  may hit the sheets S at a timing before the timing at which the transport guide  43  moves to the lowermost position, or at another timing. 
     In this embodiment, the processing tray  61  includes the sheet placing surface (upper surface  61   a ) on which the sheets S are placed. The paddle unit  34  includes the rotating shaft  49 . The transport guide  43  descends to a position aligned with at least a part of the rotating shaft  49  of the paddle unit  34  in a direction substantially parallel to the sheet placing surface. 
     According to such a configuration, the sheets S can be reliably guided to a position close to the rotating shaft  49  of the paddle unit  34  by the transport guide  43 . When the sheets S are guided to a position close to the rotating shaft of the paddle unit  34  by the transport guide  43 , the paddle unit  34  can come into contact with the sheets S at a relatively lower position. When the paddle unit  34  comes into contact with the sheets S at a relatively lower position, a contact direction T of the paddle unit  34  with respect to the sheets S is likely to be oriented in a direction substantially orthogonal to the upper surface  61   a  of the processing tray  61  or a direction oriented to the stapler  62 . Thus, it is easy to efficiently transport the sheets S, which have dropped on the processing tray  61 , toward the stapler  62 . If it is easy to efficiently transport the sheets S, which have dropped on the processing tray  61 , toward the stapler  62 , the speed-up of the post-processing apparatus  3  can be achieved. 
     However, the transport guide  43  is not limited to one that descends to the position aligned with the rotating shaft of the paddle unit  34  in the direction substantially parallel to the sheet placing surface. For example, the transport guide  43  may descend to a position lower than the base  54  of at least one of the paddles  51  and  52  in the direction substantially parallel to the sheet placing surface. Further, the transport guide  43  may descend to a position lower than an upper end of the rotating body  50  in the direction substantially parallel to the sheet placing surface. In those configurations as well, the sheets S can be guided to a relatively lower position by the transport guide  43 . As a result, it is possible to prevent the sheets S from being strongly pressed by the paddle unit  34  toward the opposite direction to the stapler  62 . 
     In this embodiment, the paddle unit  34  includes the paddles  51  and  52  that are provided separately from one another in the sheet width direction W. The transport guide  43  includes the notches  83  at positions corresponding to the paddles  51  and  52 . The paddles  51  and  52  can pass through the notches  83 . 
     According to such a configuration, it is possible to provide a transport guide  43  that extends to the upstream side of the sheet transport direction D beyond at least a part of the rotation trajectories (rotation pathways) of the paddles  51  and  52 . According to the transport guide  43  as described above, it is possible to press a portion closer to the rear edge Se of the rear end Sa of the sheets S housed in the standby tray  41 . If the portion close to the rear edge Se of the rear end Sa of the sheets S can be pressed, even in the case where the sheets S have the curl Ca, a curve of the curl Ca can be further reduced. As a result, a possibility that the paddle unit  34  comes into contact with the sheets S at a relatively higher position can be further reduced. As a result, the stability of movement of the sheets S can be further improved. 
     From a different perspective, the pressing portion  82  of the transport guide  43  is located near the sheet discharge port  31   d  of the transport path  31 . The pressing portion  82  of the transport guide  43  extends to a position that overlaps with at least a part of the rotating shaft  49  of the paddle unit  34  in the vertical direction. According to such a configuration, the pressing portion  82  can press a portion closer to the rear edge Se of the rear end Sa of the sheets S housed in the standby tray  41 . 
     In this embodiment, the transport guide  43  has a length substantially equal to or larger than the half length of the standby tray  41  in the sheet transport direction D. The turning shaft  81  is provided to the front end of the transport guide  43 . The pressing portion  82  is provided to the rear end of the transport guide  43 . In other words, according to the configuration described above, a distance between the turning shaft  81  and the pressing portion  82  is relatively large. When the distance between the turning shaft and the pressing portion  82  is relatively large, the transport guide  43  moves between the standby position and the protruding position in a relatively gentle arc. When the transport guide  43  moves in a relatively gentle arc, it is possible to prevent the transport guide  43  from causing a strong force oriented in the opposite direction to the stapler  62  to act on the sheets S. 
     In this embodiment, the transport guide  43  has a length substantially the same as the standby tray  41  in the sheet transport direction D. According to such a configuration, the distance between the turning shaft  81  and the pressing portion  82  is further increased. Thus, according to the configuration described above, it is possible to further prevent the transport guide  43  from causing a strong force oriented in the opposite direction to the stapler  62  to act on the sheets S. 
     From a different perspective, in this embodiment, the turning shaft  81  of the transport guide  43  is located at substantially the same position as the front end of the standby tray  41  in the sheet transport direction D. Further, the turning shaft  81  of the transport guide  43  is located on the downstream side of the sheet transport direction D relative to the boundary portion  45   bc  of the upper surface  45   b  of the standby tray  41 . Further, the turning shaft  81  of the transport guide  43  is located on the downstream side of the sheet transport direction D relative to the drive member  91 . According to those configurations, the distance between the turning shaft  81  and the pressing portion  82  is relatively large. Thus, according to those configurations, it is possible to further prevent the transport guide  43  from causing a strong force oriented in the opposite direction to the stapler  62  to act on the sheets S. 
     The configuration of the sheet processing apparatus is not limited to the examples described above. For example, an example of the sheet processing apparatus may be an image-forming apparatus including an inner finisher within a casing. 
     According to at least one embodiment described above, the post-processing apparatus  3  includes the standby tray  41 , the processing tray  61 , and the transport guide  43 . The processing tray  61  is provided below the standby tray  41 . The transport guide  43  includes the turning shaft  81 . The turning shaft  81  is located on the downstream side of the sheet transport direction D relative to the rear end Sa of the sheets S housed in the standby tray  41 . In the case where the sheets S are moved from the standby tray  41  toward the processing tray  61 , the transport guide  43  rotates about the turning shaft  81 , and thus presses the sheets S toward the processing tray  61  at a position on the upstream side relative to the turning shaft  81 . As a result, the stability of movement of the sheets S can be improved. 
     While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Indeed, the novel embodiments described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the embodiments described herein may be made without departing from the spirit of the inventions. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the inventions.