Patent ID: 8752819

Claim:
A sheet processing apparatus comprising: a conveyance unit configured to convey a sheet; a stacking unit configured to stack a plurality of sheets that are conveyed by said conveyance unit; a grasping member configured to perform a grasping operation that grasps a sheet surface in a rear end side of the sheets stacked on said stacking unit and a contact operation that contacts a rear end of the stacked sheets; a driving unit configured to move said grasping member; and a control unit configured to control said driving unit so that said grasping member performs the contact operation after the sheets are stacked on said stacking unit so as to align the sheets stacked on said stacking unit in a sheet conveyance direction, and to control said driving unit so that said grasping member performs the grasping operation when a following sheet is stacked on the stacked sheets, wherein said control unit makes said grasping member perform the grasping operation so as to grasp the sheet surface in the rear end side of the sheet of the stacked sheets when the following sheet is stacked on said stacking unit, and makes said grasping member perform a release operation, which separates from the sheets grasped by the grasping operation, before starting the contact operation.