Sheet processing apparatus

Abstract

A sheet processing apparatus includes a processing tray; a conveyance roller for conveying a sheet towards a downstream side in a sheet conveyance direction; a pinch roller for moving between a first position away from the conveyance roller and a second position close to the conveyance roller, and to sandwich the sheet with the conveyance roller at the second position when the sheet is conveyed by the conveyance roller. The apparatus further includes an extruding member for extruding an upstream end of the sheet from the upstream side towards the downstream side to convey the sheet placed on the processing tray. The apparatus additionally includes a controller for conveying the sheet with the extruding member after the sheet is conveyed by the pinch roller and the conveyance roller when the sheet on the processing tray is conveyed to the downstream side in the sheet conveyance direction.

1 .- 18 . (canceled) 
     
     
         19 . A sheet processing apparatus, comprising:
 a processing tray configured to stack a plurality of sheets;   a conveyance roller, arranged on a downstream side in a sheet conveyance direction with respect to the processing tray, configured to convey the plurality of sheets towards the downstream side in the sheet conveyance direction;   a pinch roller configured to move between a first position distal from the conveyance roller and a second position proximate to the conveyance roller, and to sandwich the plurality of sheets with the conveyance roller at the second position when the plurality of sheets are conveyed by the conveyance roller;   an extruder configured to extrude ends of a plurality of upstream sheets in the sheet conveyance direction from an upstream side towards the downstream side in the sheet conveyance direction to convey the plurality of sheets placed on the processing tray; and   a controller configured to
 control the conveyance roller, the pinch roller and the extruder to move the pinch roller to the second position when the plurality of sheets placed on the processing tray are conveyed to the downstream side in the sheet conveyance direction, move the pinch roller to the first position from the second position after the plurality of sheets are conveyed by the pinch roller and the conveyance roller, and then convey the plurality of sheets with the extruder; 
 switch a selection between a roller discharge process for conveying the plurality of sheets only with the pinch roller and the conveyance roller and a combined discharge process for conveying the plurality of sheets with the pinch roller, the conveyance roller and the extruder; and 
 switch the selection based on whether a number of sheets is less than a predetermined value. 
   
     
     
         20 . The sheet processing apparatus according to  claim 19 , wherein
 the controller is configured to apply a force towards the second position to the pinch roller when the plurality of sheets are conveyed by the pinch roller and the conveyance roller.   
     
     
         21 . The sheet processing apparatus according to  claim 19 , wherein
 the controller is configured to switch a selection between the roller discharge process or the combined discharge process and an extrusion discharge process for conveying the plurality of sheets only by the extruder, based on whether a sheet size is less than a threshold value.   
     
     
         22 . The sheet processing apparatus according to  claim 19 , wherein
 the controller is configured to drive the conveyance roller to rotate in the sheet conveyance direction prior to conveyance of the plurality of sheets by the extruder.   
     
     
         23 . The sheet processing apparatus according to  claim 20 , wherein
 the controller is configured to drive the conveyance roller to rotate in the sheet conveyance direction prior to conveyance of the plurality of sheets by the extruder.   
     
     
         24 . The sheet processing apparatus according to  claim 19 ,
 wherein the conveyance roller is configured to convey the plurality of sheets in the conveyance direction along a conveyance path,   wherein the conveyance path includes a first conveyance path, a second conveyance path, and a third conveyance path, the second and third conveyance paths being bifurcated from the first conveyance path.   
     
     
         25 . The sheet processing apparatus according to  claim 24 ,
 wherein the first conveyance path is arranged to guide the plurality of sheets to a standby section, the second conveyance path is configured to guide the plurality of sheets to a discharger, and the third conveyance path is arranged to guide the plurality of sheets to the processing tray.   
     
     
         26 . The sheet processing apparatus according to  claim 19 , wherein the first position is a standby position and the second position is a rotational position. 
     
     
         27 . A sheet processing method, comprising:
 arranging a conveyance roller on a downstream side in a sheet conveyance direction with respect to a processing tray in which a plurality of sheets are stacked,   causing the conveyance roller to convey the plurality of sheets towards the downstream side in the sheet conveyance direction;   providing a pinch roller to move between a first position distal from the conveyance roller and a second position proximate to the conveyance roller, and to sandwich the plurality of sheets with the conveyance roller at the second position when the plurality of sheets are conveyed by the conveyance roller;   causing an extruder to extrude ends of a plurality of upstream sheets in the sheet conveyance direction from an upstream side towards the downstream side in the sheet conveyance direction to convey the plurality of sheets placed on the processing tray;   controlling, by a controller, the conveyance roller, the pinch roller and the extruder to move the pinch roller to the second position when the plurality of sheets placed on the processing tray is conveyed to the downstream side in the sheet conveyance direction, move the pinch roller to the first position from the second position after the plurality of sheets are conveyed by the pinch roller and the conveyance roller, and then convey the plurality of sheets with the extruder; and   switching a selection between a roller discharge process for conveying the plurality of sheets only with the pinch roller and the conveyance roller and a combined discharge process for conveying the plurality of sheets with the pinch roller, the conveyance roller and the extruder,   wherein the switching is performed based on whether a number of sheets is less than a predetermined value.   
     
     
         28 . The sheet processing method according to  claim 27 , further comprising:
 applying a force towards the second position to the pinch roller when the plurality of sheets are conveyed by the pinch roller and the conveyance roller.   
     
     
         29 . The sheet processing method according to  claim 27 , further comprising:
 switching a selection between the roller discharge process or the combined discharge process and an extrusion discharge process for conveying the plurality of sheets only by the extruder, based on whether a sheet size is less than a threshold value.   
     
     
         30 . The sheet processing method according to  claim 27 , further comprising:
 driving the conveyance roller to rotate in the sheet conveyance direction prior to conveyance of the plurality of sheets by the extruder.   
     
     
         31 . The sheet processing method according to  claim 28 , further comprising:
 driving the conveyance roller to rotate in the sheet conveyance direction prior to conveyance of the plurality of sheets by the extruder.   
     
     
         32 . The sheet processing method according to  claim 27 , further comprising:
 conveying, by the conveyance roller, the plurality of sheets in the conveyance direction along a conveyance path,   wherein the conveyance path includes a first conveyance path, a second conveyance path, and a third conveyance path, the second and third conveyance paths being bifurcated from the first conveyance path.