Patent ID: 8038147

Claim:
A sheet processing apparatus which processes a sheet conveyed from an image forming apparatus, the sheet processing apparatus comprising: an aligning member which is movable in a widthwise direction orthogonal to a sheet conveying direction to align the conveyed sheet in the widthwise direction, and is movable more outwardly than an end portion of the stacking portion in the widthwise direction; a stacking portion which is provided below a position of the conveyed sheet to be aligned by the aligning member and on which the aligned sheet is stacked; and a controller which controls the aligning member so that a standby position of the aligning member, where the aligning member is on standby when said sheet processing apparatus is at power-on or between jobs, is at a position more inwardly by a predetermined amount than the outermost position in the widthwise direction, within the range through which the aligning member is movable, and so that the aligning member moves from the standby position to the outermost position when the controller receives a print signal from the image forming apparatus, and then moves inwardly from the outermost position to receive the conveyed sheet.