Patent ID: 8196915

Claim:
A sheet processing apparatus including a staple tray on which sheets conveyed from a previous unit are stacked temporarily and stapled after being aligned together and from which the stapled sheets are discharged to a discharge tray, the sheet processing apparatus comprising: a discharging unit configured to discharge a sheet to the staple tray; a rear end reference fence against which a rear end of the sheet is abutted to be aligned; a sheet returning unit configured to return the sheet discharged by the discharging unit and to align the sheet in a sheet conveying direction based on the rear end reference fence; a lifting unit configured to lift and lower the sheet returning unit with respect to the sheet; and a guiding unit configured to guide the sheet toward the rear end reference fence when the sheet is returned and to be lifted and lowered in synchronization with the lifting and lowering by the lifting unit, wherein the guiding unit is provided coaxially with the lifting unit.