Patent ID: 6962331
Filing Date: 2005-11-08
Classification: B65H

Abstract:
1. A sheet stacking apparatus comprising: a first sheet stacking device that stacks sheets; a first discharging device that discharges a sheet conveyed from an upstream side thereof toward said first sheet stacking device; a second sheet stacking device provided downstream of said first sheet stacking device, wherein a leading end of a sheet laid on said second sheet stacking device is lower in level than a highest portion of a trailing end thereof laid on said first sheet stacking device when the trailling end of the sheet is discharged from said first discharging device; a second discharging device that discharges the sheets stacked on said first sheet stacking device to said second sheet stacking device, said second discharging device being selectable between a catching state in which a sheet discharged to said first sheet stacking device is caught by said second discharging device, and a non-catching state in which a sheet discharged to said first sheet stacking device is not caught by said second discharging device; and a controller that controls said second discharging device to assume the non-catching state when said first discharging device starts discharging a sheet, and switch to the catching state before a trailing end of the sheet discharged by said first discharging device passes said second discharging device; wherein said controller provides control to change at least one selected from the group consisting of a discharging speed of said first discharging device, swinging start timing of said second discharging device, a swinging speed of said second discharging device, and a swinging acceleration of said second discharging device; wherein said second discharging device is swingable between a waiting position in which said second discharging device does not interfere with a sheet discharged by said first discharging device, and a catching position in which said second discharging device can catch the sheet discharged by said first discharging device, and wherein said controller comprises a comparison device that compares a swinging time period over which said second discharging device swings from the waiting position to the catching position and a sliding time period of a trailing end of a sheet discharged by said first discharging device calculated from a distance between a discharging position of said first discharging device and the catching position and a discharging speed of the sheet discharged by said first discharging device, and wherein said controller controls the swinging time period to a time period not more than the sliding time period.