To provide a sheet processing device capable of correctly overlapping sheets during the buffering even when the intervals of the sheets to be discharged from an image forming device are reduced.
A paper sheet P1 at the first page of the second set to be discharged from an image forming device body 10 is carried at the same speed as the discharging speed V1 of the body 10 by a pair of inlet rollers 502 to be driven by an inlet motor M1. When a rear end of the paper sheet P1 passes through the body 10, the speed of the inlet motor M1 is accelerated to the carrying speed V2 higher than the discharging speed V1. The paper sheet P1 to be carried at the carrying speed V2 is guided to a buffer path 523 by the buffer roller 505. When the paper sheet P1 is carried by the predetermined distance, the drive of a buffer motor M2 is stopped in a waiting mode. When the next paper sheet P2 to be discharged from the body 10 reaches a predetermined position, the speed of the buffer roller 505 is increased to the carrying speed V1. The overlapped paper sheets P1 and P2 are guided to a sort path 522 at the equal speed.
MIYAKE NORIFUMI
FUKATSU YASUO
MORIYAMA TAKESHI
HANADA TAKAKO
