Patent ID: 7717422

Claim:
A sheet processing apparatus that processes recording sheets conveyed from an image forming apparatus, comprising: a conveying device that conveys the recording sheets conveyed from the image forming apparatus, which conveys the sheet at a first conveying speed, one by one; a first tray on which the recording sheets conveyed by said conveying device are stacked; an aligning device that aligns the recording sheets stacked on said first tray; a second tray to which a set of the recording sheets stacked on said first tray is discharged; a discharging device that discharges the set of recording sheets stacked on said first tray as a bundle to said second tray; a controller that controls said conveying device to increase a conveyance speed of a recording sheet being conveyed by said conveying device to a second conveying speed that is greater than the first conveying speed so that a distance between the recording sheet and a succeeding recording sheet being conveyed by said conveying device is increased, wherein when a recording sheet preceding the recording sheet being conveyed by said conveying device is not a last recording sheet of a preceding set of recording sheets, said controller controls said conveying device to increase the conveyance speed of the recording sheet being conveyed by said conveying device to said second conveying speed at first timing in order to secure the time period for said aligning device to align the recording sheets stacked on said first tray, wherein when a sheet preceding the recording sheet being conveyed by said conveying device is a last recording sheet of the preceding set of recording sheets, said controller controls said conveying device to increase the conveyance speed of the recording sheet being conveyed by said conveying device to said second conveying speed at second timing later than the first timing before said recording sheet being conveyed is stacked on said first tray in order to secure the time period for said aligning device to align the recording sheets stacked on said first tray and for said discharging device to discharges the set of recording sheets stacked on said first tray, and wherein said first timing is timing at which the recording sheet being conveyed by said conveying device reaches a first position, and said second timing is timing at which the recording sheet being conveyed by said conveying device reaches a second position downstream of the first position.