Patent ID: 8505911

Claim:
A sheet discharging tray device comprising: (a) a discharging section from which a sheet is discharged; (b) a discharging tray on which the sheet discharged from the discharging section is stacked sequentially; (c) a tray drive section which drives the discharging tray in a tray shift direction that is perpendicular to a sheet discharging direction from the discharging section with reference to a sheet surface; (d) a controller which conducts a tray shift operation that shifts a position of the discharging tray under a condition of the number of sheets stacked on the discharging tray; and (e) a sheet detection section which detects an alignment deviation in the tray shift direction, wherein the controller changes an operation status of the discharging tray when a tray shift operation is conducted and changes a discharging operation of the sheet to the discharging tray, based on a detected result of the sheet detection section; and when an alignment deviation of the sheets is detected by the sheet detection section, the controller changes the operation status of the discharging tray so that movement of the discharging tray is reduced, and changes the discharging status so that a distance between adjoining sheets discharged to the discharging tray is increased.