Abstract:
A sheet post processing device receives, sheets on an inverter structure which causes initial sheets supplied to the inverter to be overlayed first sheet on the second sheet, and moves the overlayed first and second and subsequent sheets to a sheet transport path for delivery to a sheet sending device adapted to be indexed vertically between selective gates and fixed outlets into selected trays, and has a stapler for stapling sheets in sets, before sending the sets to the outlet and into a tray.

Description:
BACKGROUND OF THE INVENTION 
   This invention is related to the sheet post processing device that sorts continuously transported sheets onto several trays. 
   Previously, a movable tray type with vertically movable trays and a fixed tray type with fixed trays are known to be employed in this type of sheet post processing device. The movable tray type has an outlet in the fixed position to eject continuously transported sheets. Several trays are disposed in a vertically spaced direction and selectively move to the receiving position for the sheets ejected from the outlet. On the other hand, the fixed tray type has several transport paths that transport sheets to the respective tray. By switching those transport paths, sheets are selectively transported onto several trays. 
   However, among the previous sheet post processing devices, the movable tray type requires a large drive mechanism to move up and down heavily loaded trays due to accumulated sheets. If a sheet is ejected onto a lower tray among several trays that are located in vertically spaced direction, upper trays will significantly move to the top of the sheet infeed expanding large moving space to upper area. On the contrary, the fixed tray type requires several transport paths, complicating and enlarging the composition of the entire device. 
   There have been devices that transport the sheets that are continuously ejected from a host machine such as a copier or a printer, reverse the transport direction of the sheet, and transport the sheet into the sheet post processing portion of the device that staples and sorts the sheets. Generally, this type of sheet reversing device is incorporated into the sheet post processing device such as a stapler or a sorter. 
   The previous sheet reversing devices transport each sheet onto the stage, reverse the sheet transporting direction, and transport sheets one by one by converting the trailing end of the sheet to the leading end. After transporting one sheet onto the stage, the device transports the sheet in its reversed transporting direction. Then, after the sheet is transported, the next sheet is transported onto the stage. 
   However, since the previous sheet reversing device repeats transporting sheets one by one and in a reversed direction on the stage, the next sheet could not be transported onto the stage unless the previously transported sheet on the stage is ejected. Therefore, for example, the sheet reversing device that reverses the sheet ejected from a host machine such as a copier or a printer and transports the sheets into the sheet post processing portion for stapling or sorting takes time. If the sheet is temporarily delayed to be transported into the sheet post processing portion from the stage, the next sheet cannot be transported onto the stage and the host machine such as a copier or a printer has to be temporarily stopped. That is, due to a delay of the movement timing of the transporting destination of the sheet transported from the sheet reversing device, the transportation of the sheets into the sheet reversing device had to be stopped and therefore the speed of sheet processing decreased. 
   SUMMARY OF THE INVENTION 
   The sheet post processing device to sort continuously transported sheets into several trays has features of a top infeed to an inverter, a transport path that transports sheets continuously from the inverter, several gates from which a sheet can be taken out along the path, several outlets that can eject sheets from each corresponding fixed location of receiving trays, and the sheet sending device that selectively moves between the several transport gates and the several outlets and sends the sheets transported from the transport gates to the outlets on the other side. 
   In the sheet post processing device described herein, the sending device is disposed for vertical movement. Sheets can be taken out almost horizontally from several transport gates above the sending device. The several trays are located in fixed positions in a vertical direction. The several outlets are established in fixed positions in a vertical direction corresponding to each tray. The sheet sending device selectively moves up and down between the several transport gates and the several outlets. 
   The sheet post processing device also has a feature that the transport gates and the outlets open and close by the sheet sending device. 
   The sheet post processing device, in addition, includes a feature that the sheet sending device accumulates several sheets of papers that have been transported from the transport gate and sends them to the outlets. 
   The sheet sending device of the sheet post processing device, as described above, has a stapler to staple several sheets of accumulated sheets. 
   An objective of this invention is to provide the sheet post processing device that can sort several sheets onto several trays while simplifying and reducing the size of the composition of the entire device. 
   The sheet post processing device described above has a sheet inverting device that reverses the transporting direction of the continuously transported sheets and then sends them by the transport path to the sending device. 
   Another objective of this invention is to provide a sheet reversing device that can continuously transport sheets without any effects of delayed transporting timing and therefore to process sheets effectively. 
   The sheet reversing device of this invention establishes upper and lower sheet transporting positions on one side of the stage that can load sheets. After transporting the sheet on the stage, it ejects the sheet from the rear end of the transporting direction as the front end. The device has features of the sheet repositioning device that temporarily reposition the rear end of the transporting direction of the sheet upwardly overlays the next or second received sheet, and the sheet transporting mechanism that simultaneously transports several sheets overlaid on the stage. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a side view of the entire device of this invention in one operation format; 
       FIG. 2  is a side view to explain the outlined internal composition of the device in  FIG. 1 ; 
       FIG. 3  is a perspective of the transport gate portion of  FIG. 2 ; 
       FIG. 4  is a perspective showing the indexer portion of  FIG. 2 ; 
       FIG. 5  is a perspective of the sending mechanism portion of the indexer of  FIG. 4 ; 
       FIG. 6  is a perspective of the sending mechanism portion of  FIG. 5  in another movement mode; 
       FIG. 7  is a perspective of the sending mechanism portion of  FIG. 5  in a further movement mode; 
       FIG. 8  is a perspective of the sheet transport path portion of the indexer of  FIG. 4 ; 
       FIG. 9  is a perspective of the shutter drive mechanism of  FIG. 8 ; 
       FIG. 10  is a perspective of the outlet portion of  FIG. 8 ; 
       FIG. 11  is a view of the sheet arrangement mechanism installed in the indexer of  FIG. 4 ; 
       FIG. 12  is a view of the movement mechanism of the stapler installed in the indexer of  FIG. 4 ; 
       FIG. 13  is a flow chart to show stapling and sending movement of a pile of sheets; 
       FIG. 14  is a flow chart to show the sheet sending movement of the device in  FIG. 1  without stapling; 
       FIG. 15  is a timing chart to show the movement when the first movement mode of the device in  FIG. 1  is established; 
       FIG. 16  is a timing chart to show the movement when the second movement mode of the device in  FIG. 1  is established; 
       FIG. 17  is a side view to show another installation format of the tray in the device of  FIG. 1 ; 
       FIG. 18  is a side view to show still another installation format of the tray of the device in  FIG. 1 ; 
       FIG. 19  is a side view of the sheet reversing device of this invention; 
       FIG. 20  is a side view of the main part to explain the movement when the first sheet is transported into the sheet reversing device in  FIG. 19 ; 
       FIG. 21  is a side view of the main part to explain other movement when the first sheet is transported into the sheet reversing device in  FIG. 19 ; 
       FIG. 22  is a side view of the main part to explain the movement when the second sheet is transported into the sheet reversing device in  FIG. 19 ; 
       FIG. 23  is a side view of the main part to explain the movement when the first sheet is released from the sheet reversing device in  FIG. 19 ; 
       FIG. 24  is a side view of the main part to explain the movement when the first and second sheets start to be transported into the sheet reversing device in  FIG. 19 ; 
       FIG. 25  is a side view of the main part to explain the movement when the first and second sheets are transported into the sheet reversing device in  FIG. 19 ; 
       FIG. 26  is a perspective of the main part when the first sheet is transported into the sheet reversing device in  FIG. 19 ; 
       FIG. 27  is a perspective of the main part when the second sheet is transported into the sheet reversing device in  FIG. 19 ; 
       FIG. 28  is a flow chart to explain the movement of the reversing guide; 
       FIG. 29  is a flow chart to explain the transportation of the first and the second sheets by the sheet reversing device; and 
       FIG. 30  is a timing chart to explain the movement of the sheet reversing device. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENT 
   As seen generally in  FIGS. 1 and 2 , body  1  of the sheet post processing device, in this example, sorts the sheets that are transported in a reversed direction due to the sheet inverting device  2 . That is, a sheet ejected from a host machine such as a copier or a printer is first transported into the sheet reversing device  2  from a direction indicated by the arrow A in FIG.  2 . The transport direction of the sheet is reversed by the sheet reversing device  2  and the sheet is transported downwardly in a direction indicated by the arrow B by the transport path  10  on the right side of  FIG. 2  of the body  1 . 
   The sheet reversing device  2  transports the sheet from the direction of the arrow A onto the top of the stage  3 . It reverses the transporting direction of the sheet by converting the trailing end portion of the sheet to the leading end portion, entering the transport path  10 . 
   The transport path  10  has several pairs of rollers  11  and  12  to transport the sheet by holding it on both sides as indicated in  FIG. 3  for movement in the direction of the arrow B. In fixed positions in the transport path  10 , there are several transport gates  13  that can direct the sheet into the left side of  FIG. 2  from the transport path  10 . The transport gates  13  freely pivot around the horizontal shaft line  01  (as indicated in FIG.  3 ). L-shaped arms  14  are located on both ends of the transport gates  13  and the front end of L-shaped arms swing. The transport gates  13  are set to be in the mode not to collect the sheet without taking it out of the path when its arms  14  are placed in the first rotation position. When its arms  14  are pushed up to the second rotation position as mentioned later, it is set to be in the sheet collection mode to take the sheet out of the path and turning the sheet almost horizontally. In  FIG. 3 , the second gate from the top is set to be in the sheet collection mode. The sheet S is taken out almost horizontally in the arrow C direction while being guided by the inside  13 B of the gate  13 . The upper gate  13  in  FIG. 3  is set to be in the mode not to collect the sheet. The sheet S is transported downward while being guided by the outside  13 A of the gate. 
   Several outlets  4  that can eject the sheet as shown in  FIG. 8  are formed in the fixed position on the left side of  FIG. 2  of the body  1 . The shutter  5 A that can freely rotate around the horizontal shaft line  02  and the link  5 B that can freely rotate around the shaft line  03  are located in each outlet  4 . When the link  5 B is in the first rotation position P 11 , the shutter  5 A closes the outlet  4 . When the link  5 B is pushed upward to the second rotation position P 12  as mentioned later, the shutter  5 A opens the outlet  4 . Multiple tray installation parts are formed in the positions each corresponding to several outlets  4 . 
   Tray  6  can be selectively installed into these tray installation parts. The tray  6  receives the sheet from the outlet  4  corresponding to its tray installation and accumulates sheets. Also, the lever  7  that rotates by the accumulated sheets S as indicated in  FIG. 10  is located under each outlet  4 . This lever  7  rotates by the sheet (as indicated by the two point chain line in  FIG. 10 ) when the sheets are accumulated to its corresponding position. Then, the rear end portion  7 A causes the sensor SN 7  to turn on switch. This sensor SN 7  operates to recognize the fullness of the sheets S and moves the indexer or sending device  20  one step upward to move the outlet  4  that ejects the sheets S one step upward. 
   The indexer or sending device  20  is located between the transport gate  13  in the transport path  10  and the outlet  4  inside of the body  1  to move up and down. The indexer or sending device  20  transports the sheet S from the arrow D direction through the sheet transport path  21  on the right side of  FIGS. 2 and 4 . It loads the sheet S on the belt or stage  23  (see  FIG. 4 ) and transports the sheet toward the arrow E direction and through the sheet transport path  22  on the top left portion in  FIGS. 2 and 4 . 
   In this case, the indexer  20  can be set in the first operation mode (stapling stack mode) that staples and transports several sheets S accumulated on the stage  23  and the second operation mode (simple stack mode) that simply transports the sheets one by one. The sheet path  21  selectively faces to the transport gates  13  according to up and down movement of the indexer or sending device  20 . The sheet path  21  transports the sheets S that are taken out toward the arrow C direction from the transport gate  13  on the opposite side. Also, the sheet transport path  22  selectively faces the outlet  4  according to up and down movement of the indexer or sending device  20 . 
   The transport path  21  consists of upper and lower rollers  21 A and  21 B and upper and lower guide plates  21 C and  21 D. The roller  21 B is rotated by the entrance motor (M 4 ) that is not shown.  21 E in  FIG. 4  is a ribbed hitting roller to push down the rear end of the sheets S that are transported from the sheet transport path  21  in a transport direction onto the stage  23 . SN 5  in  FIG. 4  is the entrance sensor to detect the transportation of the sheet S in to the sheet transport path  21 . 
   The gate drive mechanism  30  (seen in  FIG. 3 ) to set the transport gate  13  facing the sheet transport path  21  into the sheet collection mode is located near the sheet transport path  21 . The gate drive mechanism  30  has the slider  31  to slide left to right in a horizontal direction by the solenoid SL 3 . The connections  31  on the both ends of the slider  31  set apart from the connection to the arm  14  of the transport gate  13  when the slider  31  is moved to the arrow F 1  direction by the spring  33 . In this case, the indexer  20  moves up and down without interference of its connection  32  with the arm  14 . On the other hand, the connection  32  moves to the connection to the arm  14  when the link  34  rotates around the shaft line  04  and the slider  31  slides toward the arrow F 2  direction. At this time, the indexer  20  moves upward and the connection  32  lifts up the arm  14  of the transport gate  13  facing the transport path  21 . The transport gate  13  is set to be in a sheet collection mode. 
   The sheet transport path  22  of the indexer  20  has the lower drive roller  22 A that is moved on the belt by the transport motor M 12  as indicated in FIG.  4  and the upper pinching roller  22 B that is moved up and down by the pinching pressure motor M 9 . The pinching roller  22 B creates pinching pressure by moving downward due to regular rotation of the pinching pressure motor M 9 . It releases the pinching pressure by moving upward due to the reverse rotation of the pinching pressure motor M 9 . The drive roller  22 A transports the sheets S on the stage  23  in the arrow E direction by rotating by the transport motor M 12 . 
   Referring to  FIGS. 8 and 9 , the shutter drive mechanism  50  to open the shutter  5 A of the outlet  4  facing the sheet transport path  22 , is located near the sheet transport path  22 . The drive mechanism  50  has the pin  51  that is caused to slide left to right horizontally by the solenoid SL 4 . 
   When the pin  51  slides toward the arrow X 2  direction, its front end portion is set apart from the connection to the link  5 B. In this case, the indexer  20  moves up and down without interference of the front end portion of the pin  51  with the link  5 B. On the contrary, when the pin  51  slides in the arrow X 1  direction, its front end portion moves into connection with the link  5 B. At this time, the indexer  20  moves upward and the front end portion of the pin  51  lifts up the link  5 B of the outlet  4  facing the sheet transport path  22  as indicated by the solid line in  FIG. 8  to open the shutter  5 A of the outlet  4 . 
   Referring to  FIGS. 4 through 7 , the sending mechanism  40  to send the transported sheets S is located on the stage  23  of the indexer or sending device  20 . Belts  41  in  FIGS. 5 ,  6  and  7  are left and right sending belts and are hung between the drive pulley  42  and the follower pulley  43 . The sending belt  41  has pins  41 A in 2 positions in equal distance in a lengthwise direction. The sending belt  51  pushes the rear end of the sheet S to the arrow E direction by sending pins  41 A in their standing position on the stage  23  to the arrow H direction.  43  is a free rotating guiding roller to guide the middle portion of the sending belt  41 . 
   At  44  is the slide plate that has the standing portion  44 A on the rear end. It is located almost on the same side as accumulating stage  23  and can slide in the arrow J 1  and J 2  directions. The slide plate  44  is connected to the belt  45  and the belt  45  is hung between the drive pulley  46  and the free rotating follower pulley  47  (see FIG.  6 ). The slide plate  44  slides in the arrow J 1  and J 2  directions between the stapling position P 21  in FIG.  5  and the sending start standard position P 22  in  FIG. 1  according to the moving direction of the belt  45 . At  48  is the spring that moves the slide plate  44  toward the arrow J 2  direction. Also, SN 12  in  FIG. 4  is a sending belt home sensor and turns on when the standing portion  44 A of the slide plate  44  moves to the prepared position. 
   The drive pulley  42  of the sending belt  41  and the drive pulley  46  of the slide plate  44  are rotated by separate drive systems (“the first drive system” and “the second drive system” respectively) that have the same sending motor M 8 . 
   The first drive system consists of a gear series L 1  with a one direction clutch. It transfers only the rotation of the pulley  49  to the drive pulley  42  when the sending motor M 8  rotates in the arrow K 1  direction. Therefore, the drive pulley  42  rotates in the arrow L direction only when the sending motor M 8  rotates in the regular arrow K 1  direction. It does not rotate when the sending motor M 8  rotates in a reverse arrow K 2  direction. On the contrary, the second drive system consists of left and right gear rows L 2 - 1  and L 2 - 2  and the one direction clutch is incorporated in the gear row L 2 - 2 . The drive pulley  46  rotates in the arrow M 2  direction only when the sending motor M 8  rotates in a reverse arrow K 2  direction and the slide plate  44  slides in the arrow J 1  direction. On the contrary, when the sending motor M 8  rotates in the arrow K 1  direction, the drive pulley  46  can freely rotate in the arrow M 1  direction and the slide plate  44  returns to the arrow J 2  direction by the spring  48 . 
   Also, as seen in  FIGS. 4 ,  11  and  12 , the indexer  20  has the sheet arrangement mechanism  70  to arrange the sheet S on the stage  23  from left and right directions. In  FIG. 11 ,  71 A and  71 B are left and right guide plates and they are guided to be able to slide in the left and right arrows P 1 , P 2  and Q 1 , Q 2  directions by the guide slots  72 A and  72 B. The left guide plate  71 A is connected to the belt  75 A that is hung between the pulleys  73 A and  74 A. It slides to left and right arrows P 1  and P 2  directions by being rotated by the sheet arrangement motor M 3 -A. Similarly, the right guiding plate  71 B is connected to the belt  75 B that is hung between the pulleys  73 B and  74 B. It slides to left and right arrows Q 1  and Q 2  directions by being rotated by the sheet arrangement motor M 3 -B. 
   Motors M 3 -A and M 3 -B are relatively controlled. When each motor rotates in a regular direction, left and right guiding plates  71 A and  71 B slide to the arrows P 1  and Q 1  directions that are closely connected to arrange the sheet S. When each motor rotates in a reverse direction, left and right guiding plates  71 A and  71 B slide to the arrows P 2  and Q 2  that are apart from each other to release the sheet arrangement. 
   Furthermore, the indexer  20  has the stapler  80  to staple the rear end of the sheets accumulated on the stage  23 . The stapler  80  in this example can selectively move to a position to staple the rear right end of the sheets as indicated by the solid line in FIG.  12  and to a position to staple the rear left end of the sheets as indicated by the two point chain line in FIG.  12 . That is, the stapler  80  is equipped to be freely rotated around the shaft line  05  on the slider  81 . The slider  81  is guided to be able to slide in left and right directions by the guiding slot  82 . The slider  81  is connected to the belt  84  that is hung through the pulleys  83 A,  83 B,  83 C and  83 D and slides left and right when the pulley  83 A is rotated by the motor M 1  seen in FIG.  12 . 
   Reference characters  85 A and  85 B are left and right stoppers that are fixed in the fixed positions. As indicated by the solid line in  FIG. 12 , when the slider  81  slides to the right, the right stopper  85 B directly connected to stapler  80  and the stapler  80  rotates to the position to staple the rear right portion of the sheet. Also, as indicated by the two point chain line in  FIG. 12 , when the slider  81  slides to the left, the left stopper  85 A directly connects to the stapler  80  and the stapler  80  rotates to the position to staple the rear left portion of the sheet. 
   The indexer  20 , as mentioned before, selects the transport gate  13  that transports the sheet S and the outlet  4  that ejects the sheet S according to the movement position in up and down direction. That is, the indexer  20  receives the sheet S from a corresponding transport gate  13  and then ejects the sheet S from the corresponding outlet  4  according to the first and second movements as mentioned later. Therefore, by installing the tray  6  to the outlet  4 , the indexer  20  can sort the sheet S or a pile of sheets onto the multiple trays  6 . For example, the indexer can also cause each tray  6  to function as a mailbox. In the cases of  FIGS. 1 and 2 , a total of five trays  6  are installed and the bottom tray  6  is a large capacity tray. When the sheet S or a pile of sheets fill up on the tray  6 , the sensor SN 7  detects the fullness. 
   Also, by assigning several outlets  4  to one tray  6  to store the sheet S or a pile of sheets ejected from these outlets  4  in one tray  6 , the storage capacity of the tray  6  can be expanded. In that case, by using several sensors SN 7  corresponding to each outlet  4  that is assigned to one tray  6 , the outlet  4  that should eject the sheet S or a pile of sheets can be selected to switch from the bottom, in order, according to the increase of accumulated amount of the sheet S or a pile of sheets on one tray  6 . 
     FIG. 15  is a time chart to explain the movement of the indexer  20  at the time of establishment of the “first movement mode”. 
   When establishing the first movement mode, the slide plate  44  is located in the stapling position P 21  as shown in FIG.  7  and the nail  41 A of the sending belt  41  is located on the bottom of the stage  23 . The rear end of the sheet S that is transported onto the stage  23  of the indexer  20  is located in the stapling position P 21  by the standing portion  44 A of the slide plate  44  as indicated by the two point chain line in FIG.  7 . The sheets S that are transported onto the stage  23  in this manner accumulate and form a pile of sheets. 
   Regarding the final sheet S of the pile of sheets, the transportation of the final sheet S is detected by the entrance sensor SN 5  (see  FIG. 4 ) as shown in  FIG. 15  at (a). Then, the entrance motor M 4  (not shown) to rotate the roller  21 B of the sheet transport path  21  is turned on as shown in  FIG. 15  at (b) and the final sheet S is transported onto the stage  23 . After the specified time from the declining point t1 of the detection signal of the entrance sensor SN 5 , the sheet arrangement motors M 3 -A and M 3 -B rotate in a regular direction and the guiding plates  71 A and  71 B of the sheet arrangement mechanism  70  move toward one another to arrange the sheets. 
   The stapler  80  staples a pile of sheets that has been arranged by the guiding plates  71 A and  71 B as shown in  FIG. 15  at (d). then, the sheet arrangement motors M 3 -A and M 3 -B rotate in a reverse direction, as shown in  FIG. 15  at (c). After the guiding plates  71 A and  71 B separate and release the sheet arrangement, the pile of sheets that have already been stapled is sent in three stages. 
   In other words, first of all, during the first stage, the sending motor M 8  rotates in a reverse direction, as shown in  FIG. 15  at (e) and the slide plate  44  slides to the sending start standard position P 22  to send a pile of sheets as indicated in FIG.  6 . 
   During the second stage, the sending motor M 8  rotates in a regular rotation and the pin  41 A of the sending belt  41  moves to the sending start standard position P 22  that is indicated by the two point chain line in FIG.  6 . Then, it further moves to the arrow H direction to send a pile of sheets. Then, the sending motor M 8  further rotates in a regular direction to the point t3that turns on the sending belt home sensor SN 12  (see FIG.  4 ), and a pile of sheets is definitely sent to the sheet transport path  22 . At step  57 , at this point, since the transport motor M 12  turns on as shown in  FIG. 15  at (g) and the pinching pressure is created when the pinching pressure motor M 9  rotates in a regular direction as shown in  FIG. 15  at (h), the sheet transporting path  22  can be activated, and, therefore, during the third stage, the sheet transport path  22  sends the sheets. 
   The pinching pressure motor M 9  rotates in a reverse direction to release pinching pressure and the sending motor M 8  rotates in a regular direction to return the sending belt  41  to the initial position in FIG.  7 . That is, one of two nails  41 A on the sending belt  41  that was previously sending a pile of sheets in the second stage as indicated in  FIG. 7 , and the other nail  41 A positions itself to be a waiting position to send the next pile of sheets as indicated in the right side of FIG.  7 . 
   The sheet S that consists the next pile of sheets is transported onto the stage  23 . Sheet arrangement motors M 3 -A and M 3 -B arrange sheets by repeating regular and reverse rotations every time when the sheet S is transported as indicated in  FIG. 15  at (c). 
     FIG. 13  is a flow chart to explain the stapling in the described above “first movement mode” and the sending movement of a pile of sheets. That is, when the final sheet S composed of a pile of sheets is transported (step S 1 ), the sheet S is stapled while being arranged (steps S 2  and S 3 ), then the sheet arrangement movement is released (step S 4 ) and a pile of sheets is sent to the third stage as described above (steps S 5 , S 6  and S 7 ). 
     FIG. 16  is a time chart to explain the movement when the indexer  20  is in the “second movement mode”. 
   When the second movement mode is being established, the slide plate  44  moves away to the staple P 21  position as indicated in FIG.  5  and the nail  41 A of the sending belt  41  positions itself on top of the stage  23  in the sending start position P 22 . Therefore, the rear end of the sheet S transported onto the stage  23  of the indexer  20  is positioned in the sending start position P 22  by the nail  41 A of the sending belt  41  as indicated in the two point chain line in FIG.  5 . Then, the sheet S is transported onto the stage  23  in this manner one by one. 
   First of all, the transportation of the sheet S is detected by the entrance sensor SN 5  (see  FIG. 4 ) as indicated in  FIG. 16  at (a). The entrance motor M 4  to rotate the roller  21 B of the sheet transport path  21  is then turned on as indicated in  FIG. 16  at (b) and the sheet S is transported onto the stage  23 . Then, after the specified time passes after the starting time t11 when a detection signal of the entrance sensor SN 5  is activated, the sheet arrangement motors M 3 -A and M 3 -B rotate in a regular direction, then in a reverse direction as indicated in  FIG. 16  at (c) and the sheet arrangement mechanism  70  arranges the sheet and releases the sheet arrangement. 
   That is, first of all, the sending motor M 8  reverses in a regular direction as indicated in  FIG. 16  at (d) during the first stage and the nail  41 A of the sending belt  41  moves toward the arrow H direction from the sending start position P 22  in  FIG. 5  to send the sheet S. Then, the sending motor M 8  further rotates in a regular direction until the sending belt home sensor SN 12  (see  FIG. 4 ) is turned on (t13) and the sheet S is sent into the sheet transport path  22 . At this time, since the transport motor M 12  is turned on as indicated in  FIG. 16  at (f) and the pinching pressure motor M 9  rotates in a regular direction to create pinching pressure, the sheet transport path  22  has already been in the transportable condition. Therefore, the stage  23  is to send the sheet by the sheet transport path  22 . 
   Then, the pinching pressure motor M 9  rotates in a reverse direction to release pinching pressure and the sending motor M 8  rotates in a regular direction to return the sending belt  41  to the initial position in FIG.  5 . That is, one of two nails  41 A on the sending belt  41  that was sending the sheet S during the first stage positions itself as indicated in the left side of FIG.  5  and the other nail  41 A positions itself to wait for the next sheet to be sent in the sending start position P 22  as indicated in the right side of the same figure. 
   Similarly, the sheet S to be transported onto the stage  23  is transported one by one. 
     FIG. 14  is a flow chart to explain the sheet sending movement in the “second movement mode” described above. That is, when the sheet S is transported (step S 11 ) the sheet is arranged. After the sheet is arranged and then that arrangement is released (steps S 12  and S 13 ), the sheet S is transported to the second stage as described above (steps S 14  and S 15 ). 
   There are other constructions possible.  FIG. 17  is an example of the installation of the tray  6  and  FIG. 18  is an example of a total of two trays  6 . The trays  6  are installed to several tray installation portions each corresponding to several outlets  4  and the sheet S or a pile of sheets can be sorted into these trays  6 . 
   As described above, the sheet post processing device of this invention can selectively move the sheet sending device in the opposite directions to several outlets that are fixed in the same position as several fixed transport gates. The sheet sending device of the sheet post processing device sends the sheet that was transported from the transport gate according to its position and sorts the sheet onto the fixed tray corresponding to the outlet. Since it can sort sheets by moving the sheet sending device without moving the tray, it helps to simplify and minimize composition of the entire device and it can also sort sheets like a fixed tray functioning as a mailbox. 
   The sheet reversing device  2  is constricted to keep the sheet S retained on the stage  120  on the top right diagonal direction in FIG.  19 . In this example, this stage  120  is composed of the first section  21  with the inclined angle on the right side of FIG.  19  and the second stage  122  with the larger inclined angle on the left side of FIG.  19 . As indicated in  FIG. 26 , the first stage  121  is a flat section  121 A and a second is a ribbed section  122 A. 
   In  FIG. 19 , P 1  is a sheet transport established between upper and lower rollers  131  and  132  located near the top of the stage  120 . P 2  is also a sheet transport established between upper and lower transporting rollers  141  and  142  located at the low end of the stage  120 . The transporting rollers  131  and  132  compose the sheet transport mechanism  30  along with upper and lower rollers  133 ,  134 ,  135  and  136 . They send the sheet S as indicated by the two-point chain line in  FIG. 19  that was ejected from a host machine such as a copier or a printer in the arrow A direction and transport it from the sheet transporting position P 2  on the stage  120 . SN 1  is a transporting position sensor to detect the passage of the sheet S transported from the sheet transport position P 2 . SN 2  is a transporting position sensor to detect the passage of the sheet S transported from the sheet transport position P 2 . The sending rollers  141  and  142  compose a sheet transport mechanism  140  to send the sheet S located in the sheet transport position P 2  into the sheet transport path  10  along the arrow B direction in FIG.  2 . 
   A reversing guide  151  is a rotary body located in the left of the sheet transport position P 1  of rollers  131  and  132 . It is located in the repositioning device  150  (see  FIG. 26 ) to temporarily reposition the rear end of the sheet S transported from the sheet transport position P 1  on the top of sheet transport position P 1 . The section of that reversing guide  51  is a half moon shape that can rotate around the horizontal shaft line  01 . It is also divided into several guides along the shaft line  01  and they rotate through a gear row by the reversing guide motor M 1 . The reversing guide  51  rotates between the waiting position as indicated in  FIG. 20  or the stock position (usually the same position as the transporting position) as indicated in FIG.  21 . The stock waiting position is the first position with the swelled portion  151 A in a diameter direction of the reversing guide  151  located in the lower portion as indicated in FIG.  26  and the cut-out portion  151 B located in the upper portion. The normal position (usually the same position as the transport position) is the second position rotated 150 degrees to the right from the waiting position as indicated in FIG.  27 . The reversing guide  151  guides the sheet S from the sheet transport position P 1  onto the top of the stage  120  through its cut-out portion  151 B as mentioned later. Its swelled portion  151 A reposition the rear end of the transporting direction of the sheet S upward. 
   The friction roller (elastic material)  111  is located on the top of the reversing guide  51 . The shaft  111 A of this friction roller  111  is guided freely up and down in the guide slit  112  on the body side of the sheet reversing device  2  as indicated in FIG.  20 . It is also pushed downward by the spring  13 . 
   A stopper  114  is located on the right end of  FIG. 20  of the first stage  121  and can move up and down to position the front end of the infeed direction of the sheet S. This stopper  114  moves up and down by rotating around the supporting shaft  114 A by the stopper solenoid SL 1 . 
   The sheet transporting mechanism  60  is located on the stage  120  to send the sheet S that is transported onto the stage  120  toward the sheet transport position P 2 . The sheet transporting mechanism  160  in this example has the pusher  164  that guides the second stage  122  to be able to slide in the arrows C 1  and C 2  directions by the guide bodies  161 ,  162  and  163  as indicated in FIG.  26 . This pusher  164  is a flanged section of the guide block  165  that is guided to freely slide in the guide body  161 , the guide blocks  166  and  167 , that is, it guides to freely slide in the guide slits  162 A and  163 A of the guide bodies  162  and  163 . The pusher  164  is connected to the belt  168  that moves by the pusher motor M 2  and the belt  168  is hung between the drive pulley  169  of the pusher motor M 2  and the guiding pulleys  170 ,  171  and  172 . The pusher  164  is driven on the belt in the arrows C 1  and C 2  directions by the pusher motor M 2 . 
     FIG. 30  is a timing chart to explain examples of the movements of the sheet reversing device  2 . In this example, the sending mechanism  20  accumulates three pieces of the sheet S, staples that pile of sheets by the stapler  80 , and transports them onto the tray  6 . In such a sheet post processing, due to the time required for stapling after the third sheet S is accumulated in the sending mechanism  20 , the sending mechanism  20  may not be able to continuously transport the first sheet S of the pile from the sheet reversing device  2 . Examples of the movements of the sheet reversing device  2  in  FIG. 30  are applications of such sheet post processing. 
   The sheet S is transported into the sheet reversing device  2  from the sheet transport position P 1  and is detected by the transport position sensor SN 1  as indicated in FIG.  30 . If the final or the third sheet S of the pile is transported, the reversing guide motor M 1  rotates in a regular direction for the specified amount after waiting for the third sheet S to be completely transported onto the stage  120  from the time when the detection signal of the transport position sensor SN 1  is activated (t1). The reversing guide  51  rotates 150 degrees to the left from the regular transport position as indicated in FIG.  19  and sets itself in the stock waiting position as indicated in FIG.  20 . After the time t2 when the reversing guide  151  rotates to the stock waiting position in  FIG. 20 , the pusher motor M 2  rotates in a regular direction and then in a reverse direction. By the regular rotation of the pusher motor M 2 , the pusher  164  moves from the position in  FIG. 19  to the arrow C 1  direction, pushes the third sheet S on the stage  120 , and sends it toward the sheet transport position P 2 . The third sheet S is transported from the sheet transport position P 2  by the sheet transporting mechanism  140 . Therefore, the third sheet S is transported from the sheet transport position P 2  from the rear end of the transporting direction as the front end and the transporting direction is reversed. The pusher  164  moves in the arrow C 2  direction by the reverse rotation of the pusher motor M 2  and return to the waiting position in FIG.  19 . 
   The third sheet S that is transported from the sheet transport position P 2  is detected by the transport position sensor SN 2  as indicated in FIG.  14 ( b ). After the time when the detection signal of that sensor SN 2  is activated, that is, after the third sheet S is transported, the stopper solenoid SL 1  moves out and the stopper  114  elevates to be in the set mode as indicated in  FIG. 22  (see FIGS.  14 ( f ) and ( g )). In this example, the transporting speed of the sheet S by the sheet transporting mechanism  140  is established slower than the transporting speed of the sheet transporting mechanism  30 . In  FIG. 30 , the ejection position sensor SN 2  detected the third sheet S before the regular rotation of the pusher motor M 2  starts. This is because the third sheet S is transported from the sheet transport position P 1  and naturally reached at the sheet transport position P 2 . 
   Then, if the first sheet S of the next pile of the sheets (“the first sheet S-I”) is transported, it passes over the reversing guide  151  and is transported onto the stage  120  as indicated in FIG.  20 . After the time t4 when the detection signal of the transport position sensor SN 1  activated, the reversing guide motor M 1  rotates in a reverse direction, the guide  151  rotates 150 degrees to the right from the stock waiting position in FIG.  20  and is set in the stock position as indicated in FIG.  21 . The rear end of the transporting direction of the first sheet S- 1  is lifted upward by the reversing guide  51  as indicated in  FIG. 21 , is repositioned on the top of the sheet transport position P 1 , and is held between the reversing guide  151  and the friction roller  111 . 
   Then, the second sheet S transported from the sheet transport position P 1  (“the second sheet S- 2 ”) is transported onto the stage  120  as it is being inserted under the first sheet S- 1 . And, after the time t5 when the detection signal of the transport position sensor SN 1  is activated, the reversing guide motor M 1  rotates in a regular direction, the reversing guide  151  rotates 360 degrees to the left as indicated in  FIGS. 23 and 24  from the stock position in  FIG. 22 , and it returns to the regular transport position in FIG.  19 . As indicated in  FIGS. 23 and 24 , the upward repositioning of the first sheet S- 1  by the reversing guide  151  is released and the sheets are accumulated on top of the second sheet S- 2 . 
   And, after the time t6 when the reversing guide motor M 1  stops rotating, the pusher motor M 2  rotates in a regular direction over two stages as indicated in FIG.  14 ( c ) and the pusher  164  sends the first and second sheets S- 1  and S- 2  in two stages. That is, the first stage transportation is to push small amounts of the sheets S- 1  and S- 2  to the arrow C 1  direction and push the front end of the transporting direction to the stopper  114  to arrange those sheets. After the time t7 when this stage transportation is completed, the stopper solenoid SL 1  returns as indicated in FIG.  14 ( f ) and the stopper  14  comes down to be in a release mode as indicated in  FIG. 24  (see FIG.  14 ( g )). The second stage transportation is conducted after the time t8 when the stopper solenoid SL 1  returns and the pusher  164  sufficiently moves to the arrow C 1  direction to send the sheets S- 1  and S- 2  to the transport position P 2 . Those sheets S- 1  and S- 2  are simultaneously transported from the sheet transport position P 2  by the sheet transport mechanism  140 . 
   Then, the third sheet S that is transported onto the stage  120  is transported to the sheet transport position P 2  by the regular rotation of the pusher motor M 2 . 
     FIG. 28  is a flow chart to explain the movement of the sheet reversing guide  151 . The sheet reversing guide  151  rotates to the stock waiting position from the regular transport position (steps S 1  and S 2 ) after transporting the final sheet (the third sheet). Then, the first sheet S- 1  of the next sheet pile is transported and is rotated to the stock position (steps  3  and  4 ) and then the sheet reversing guide  151  rotates to the regular transport position after the second sheet S- 2  is transported (steps S 5  and S 6 ). 
     FIG. 29  is a flow chart to explain the transportation of the first and the second sheets S- 1  and S- 2  that are accumulated on the stage  120 . After the final sheet (the third sheet) of the previous sheet pile is transported, the stopper  14  moves upward to be in a set mode (steps S 11  and S 12 ), then the sheets S- 1  and S- 2  are accumulated on the stage  120  (step S 13 ) and are transported over two stages as mentioned before. that is, the pusher  164  arranges the sheets S- 1  and S- 2  in the first stage transportation, then pushes down the stopper  114  (step S 15 ) and the pusher  164  transports the sheets S- 1  and S- 2  to the sheet transport position P 2  in the second stage transportation (step S 16 ). 
   The sheet reversing device  2  transports the first sheet S- 1  and the second sheet S- 2  together and delays the transportation of the sheet S- 1  until the sheet S- 2  is transported. It extends the period between the transportation of the final sheet (the third sheet) of the previous sheet pile and the transportation of the first and the second sheets S- 1  and S- 2  of the following sheet pile. 
   Stapling time of the sheet pile by the stapler  80  is secured within the extended period. By delaying the transportation timing of the sheet S to the sending mechanism  20  by the sheet reversing device  2 , the sheet post processing delay due to stapling is compensated and the host machine can continuously transport the sheets S regardless of the delay in sheet post processing. Also, since the sheet reversing device  2  transports the first sheet S- 1  over the second sheet S- 2 , the second and the third sheets S are accumulated over the first sheet S in the sending mechanism  20 . Its accumulation order does not change. 
   As explained above, the sheet reversing device of this invention reposition the rear end of the transporting direction of the sheet transported previously on the stage upward, overlays the transported sheet on top of the next transported sheet, transports these sheets from the rear end of the transporting direction as the front end, continuously transports the sheet without being affected by the delay in movement of the sheet transporting destination, and effectively processes the sheets.