Patent ID: 8454016

Claim:
A sheet stacking apparatus comprising: a plurality of stacking portions arranged side by side, each stacking portion having a tray on which a sheet is stacked and which can move up and down separately ; a discharging portion configured to discharge a sheet from one of a plurality of discharging positions to a corresponding stacking portion of the plurality of stacking portions selectively, each discharging position provided to correspond with each of the plurality of stacking portions; a guiding unit which can move across the plurality of stacking portions and has a stopper that overlaps the tray on which there is no sheet so that a regulating surface of the stopper, regulating the sheet discharged from the selected discharging position to the tray of the corresponding stacking portion, intersects with a stacking surface of the tray and a guiding member that guides a downstream end in a discharge direction of the discharged sheet to the stopper; and a controller configured to control movement of the guiding unit so that the guiding unit is moved to a position where the stopper regulates the sheet discharged from the selected discharging position to the corresponding stacking portion.