Patent ID: 7766315
Filing Date: 2010-08-03
Classification: B65H

Abstract:
1. A sheet stacking apparatus comprising: first and second sheet-stacking units configured to stack sheets discharged from an image forming apparatus thereon; lifting driving units configured to cause lifting and lowering operations of said first and second sheet-stacking units; a control unit configured to cause selective execution of one of a first stacking mode in which sheets are caused to be stacked on one of said first and second sheet-stacking units, and a second stacking mode in which sheets are caused to be stacked in a state extending on said first sheet-stacking unit and said second sheet-stacking unit; and an abnormality determination unit configured to determine whether or not any of said first and second sheet-stacking units is abnormal in a lifting/lowering operation by said lifting driving units, wherein when said abnormality determination unit determines that one of said first and second sheet-stacking units is abnormal in the lifting/lowering operation, said control unit inhibits execution of the second stacking mode, and permits execution of the first stacking mode using the other of said first and second sheet-stacking units.