Patent ID: 7918450

Claim:
A sheet processing apparatus comprising: a conveying unit that conveys a sheet from an upper-level apparatus; a conveyance control unit that changes a conveying speed of the sheet from a first conveying speed to a second conveying speed to extend an interval between a current sheet and a next sheet from the upper-level device increases; a first tray unit that stacks therein the sheet conveyed by the conveying unit; an aligning unit that aligns sheets stacked in the first tray unit; a second tray unit that stacks therein a stack of sheets discharged from the first tray unit; a discharging unit that discharges the stack of sheets from the first tray unit to the second tray unit; and a holding unit that holds a trailing end of the stack of sheets stacked in the second tray unit, wherein when a sheet is conveyed to an acceleration position where the conveying speed can be changed from the first conveying speed to the second conveying speed while the discharging unit is discharging a preceding stack of sheets, the conveyance control unit calculates a third conveying speed for conveying the sheet based on a first conveyance time to be taken until a leading end of the stack of sheets reaches the second tray unit and a second conveyance time to be taken until a current discharging operation of the stack of sheets is completed from a start of the current discharging operation, and changes the conveying speed from the first conveying speed to the third conveying speed, wherein after changing the conveying speed from the first conveying speed to either one of the second conveying speed and the third conveying speed, the conveyance control unit changes the conveying speed from either one of the second conveying speed and the third conveying speed to a fourth conveying speed before the sheet is conveyed to the first tray unit.