Patent ID: 7717414

Claim:
A sheet processing apparatus comprising: a sheet feeding tray capable of aligning and storing plural sheets; a discharging member for discharging a sheet at a top of a bundle of the sheets aligned from the sheet feeding tray; a retracting member for moving the sheet at the top of the sheet bundle to a position retracted in a direction opposite to a direction of the discharge; and a control unit configured to control operations of the discharging member and the retracting member, wherein when plural pieces of plural types of sheets are stacked and stored in the sheet feeding tray, the control unit controls the operations of the discharging member and the retracting member according to the types and the number of the sheets, discharges, for each of the types, a sheet located at the top of the sheet feeding tray and retracts remaining sheets, performs alignment again at a point when the discharge and the retraction are finished for all the types, and repeats this series of operations to sequentially discharge the sheets of the respective types.