SHEET STACKING DEVICE

PROBLEM TO BE SOLVED: To provide a sheet stacking device capable of detecting the sheet stacking state with excellent accuracy without any improper operation even when a user carelessly re-feed sheets in a tray. SOLUTION: The sheet stacking device comprises a movable lever 14 which is provided in a vicinity of a sheet discharge port 12 to discharge sheets on a tray 11, abutted on an upper side of the sheets stacked on the tray, and turned, a sensor to detect the stacking state of the sheets stacked on the tray 11 as the movable lever 14 is turned, and a first preventive means 16 which is provided in an upper space part of the tray 11 on the downstream side of the sheet discharging direction of the movable lever 14 to prevent insertion of the sheets above the movable lever 14 in the direction opposite to the sheet discharging direction. Any sheet is not inserted above the movable lever 14. COPYRIGHT: (C)2007,JPO&INPIT