Patent ID: 8915492

Claim:
A sheet finishing apparatus comprising: a processing tray on which a sheet conveyed from an image forming apparatus is stacked; a finishing section configured to apply a finishing process to the sheet on the processing tray; a sheet discharging section configured to discharge the sheet subjected to the finishing process to a stack tray via a discharge port; a roller attached to a shaft provided in parallel to the discharge port and configured to rotate in a first direction for guiding the sheet in a direction of the finishing section and in a second direction for discharging the sheet; and an arm attached to the shaft and extending radially from the shaft, the arm rotating in accordance with a rotation of the shaft in a first direction to a first position where the arm contacts a regulating member provided on the processing tray and not rotating further in the first direction after contacting the regulating member even if the shaft continues to rotate in the first direction, and the arm rotating in accordance with a rotation of the shaft in a second direction to a second position where the arm contacts a trailing portion of a sheet stacked on the stack tray and not rotating further in the second direction after contacting the location even if the shaft continues to rotate in the second direction.