Patent ID: 8714538

Claim:
A sheet stacking apparatus comprising: an acquisition unit configured to acquire information about a weight of a sheet to be conveyed; an overlapping unit configured to overlap the sheet to be conveyed with another sheet and convey the overlapped sheets; a stacking tray onto which a sheet bundle conveyed as overlapped sheets by the overlapping unit, or a sheet conveyed without being overlapped with another sheet by the overlapping unit, is discharged; an alignment unit configured to align sheets stacked on the stacking tray; and a control unit configured to discharge the sheet onto the stacking tray by overlapping with another sheet by the overlapping unit if information about the weight of the sheet acquired by the acquisition unit indicates weight less than predetermined weight, and discharge the sheet onto the stacking tray without overlapping with another sheet by the overlapping unit if the information about the weight of the sheet acquired by the acquisition unit indicates weight not less than the predetermined weight.