Sheet post-processing apparatus

Abstract

A sheet post-processing apparatus includes a saddle tray on which are stacked bundles of sheets having undergone center folding processing and a movable tray that ascends and descends while sheets having undergone post-processing other than center folding are stacked thereon. The saddle tray is coupled to the movable tray and a mechanism to allow the saddle tray to ascend and descend in association with the movable tray is provided. The movable tray is driven to a lower position before the bundles of sheets are discharged for the bundles of sheets to be stacked on the saddle tray. After the bundles of sheets are discharged, the movable tray is driven to an upper position for the stacking portion of the saddle tray to standby at a high position.

1 . A sheet post-processing apparatus, comprising:
 a movable tray allowed to ascend and descend and configured to stack thereon sheets having undergone post-processing;   discharge means for discharging bundles of sheets having undergone center folding processing; and   a saddle tray provided at a lower position from the movable tray and configured to stack thereon the bundles of sheets discharged via the discharge means,   wherein the saddle tray is coupled to the movable tray.   
     
     
         2 . A sheet post-processing apparatus, comprising:
 a movable tray allowed to ascend and descend and configured to stack thereon sheets having undergone post-processing;   discharge means for discharging bundles of sheets having undergone center folding processing;   a saddle tray provided at a lower position from the movable tray and configured to stack thereon the bundles of sheets discharged via the discharge means; and   an arm member configured to press the bundles of sheets stacked on the saddle tray in a direction of a stacking surface of the saddle tray,   wherein the saddle tray and the arm member are coupled to the movable tray.   
     
     
         3 . The sheet post-processing apparatus according to  claim 1 , wherein:
 the saddle tray includes a sheet stacking unit configured to stack the bundles of sheets and a stopper configured to prevent the bundles of sheets stacked on the sheet stacking unit from falling off; and   the stopper is formed to stand on the sheet stacking unit at a tip end portion on a downstream end in a transportation direction of the bundles of sheets.   
     
     
         4 . The sheet post-processing apparatus according to  claim 2 , wherein:
 the saddle tray includes a sheet stacking unit configured to stack the bundles of sheets and a stopper configured to prevent the bundles of sheets stacked on the sheet stacking unit from falling off; and   the stopper is formed to stand on the sheet stacking unit at a tip end portion on a downstream end in a transportation direction of the bundles of sheets.   
     
     
         5 . The sheet post-processing apparatus according to  claim 2 , wherein:
 the arm member has an oscillation supporting point between the movable tray and the saddle tray and is configured to be able to oscillate in response to a height of the bundles of sheets stacked on the saddle tray.   
     
     
         6 . The sheet post-processing apparatus according to  claim 2 , wherein:
 the arm member includes a guide member on the paper discharge means side that is configured to guide the bundles of sheets in the direction of the stacking surface of the saddle tray; and   the guiding member is configured to oscillate upon contact with the bundles of sheets discharged from the paper discharge means so as to be capable of absorbing a force in the transportation direction of the bundles of sheets.   
     
     
         7 . The sheet post-processing apparatus according to  claim 2 , wherein:
 the arm member includes a rotatable guide roller at a tip end portion on a downstream end of a transportation direction of the bundles of sheets.