| 摘要 |
A sheet stacking device (25) includes a device main body (23), a sheet discharge unit (135), a sheet stacking portion (26) and a sheet detector (7). The sheet discharge unit discharges sheets. The sheet stacking portion includes a sheet stacking surface on which the sheets are to be stacked. The opening (252) is formed in the sheet stacking surface. The sheet detector includes a detection piece (721B) capable of projecting upwardly of the sheet stacking surface from the opening. The sheet detector detects a first state, a second state and a third state. The first state is a state where no sheet is placed on the sheet stacking surface. The second state is a state where a first number of the sheets discharged are placed on the sheet stacking surface. The third state is a state where a second number of the sheets larger than the first number are placed on the sheet stacking surface. |
