Patent ID: 8038138

Claim:
A finisher comprising: a standby tray configured to temporarily hold a plurality of sheets to form a first sheet bundle and to drop the first sheet bundle after the first sheet bundle is formed; a processing tray configured to receive the first sheet bundle dropped from the standby tray; a stapling unit configured to staple the first sheet bundle on the processing tray; a discharge unit configured to discharge the first sheet bundle stapled by the stapling unit from the processing tray; and a control unit configured: to control the standby tray to form a part of a second sheet bundle subsequent to the first sheet bundle until the discharge unit discharges the first sheet bundle, to control the standby tray to receive a sheet of the first sheet bundle and the subsequent sheet of the first sheet bundle within a first period, to control the standby tray to receive the last sheet of the first sheet bundle and a first sheet of the second sheet bundle within a second period as same length as the first period, and to control the standby tray to receive a sheet of the second sheet bundle and the subsequent sheet of the second sheet bundle within a third period that is equal to the first and second periods in time length if the discharge unit has discharged the first sheet bundle and is different from the first and second periods in time length if the discharge unit has not discharged the first sheet bundle.