Patent ID: 8011654

Claim:
A sheet stacking apparatus comprising: a sheet stacking portion on which sheets are stacked; a sheet conveying portion which conveys the sheets to discharge the sheets successively onto the sheet stacking portion; a first aligning member which aligns a position of a downstream edge in a sheet conveying direction of a sheet stacked on the sheet stacking portion by a movement of the first aligning member from a standby position to an aligning position along the sheet conveying direction of the sheet conveying portion; a second aligning member which aligns a position in a width direction of the sheet stacked on the sheet stacking portion by a movement of the second aligning member from a standby position to an aligning position in the width direction crossing the sheet conveying direction; and a controller for controlling said sheet stacking apparatus, wherein said controller controls said sheet stacking apparatus so that when sheets conveyed by the sheet conveying portion are successively discharged onto the sheet stacking portion, an aligning operation in which an uppermost sheet of the sheets discharged onto the sheet stacking portion is aligned first by the second aligning member and aligned second by the first aligning member is performed with the stacking of each sheet, and said controller controls said sheet stacking apparatus so that after the second aligning member, which has been moved to the aligning position to align the uppermost sheet, is returned to the standby position and during the movement of the first aligning member between the standby position and the aligning position to align the uppermost sheet, the sheet conveying portion conveys a next sheet to discharge the next sheet onto the sheet stacking portion.