Patent ID: 7900912

Claim:
A sheet processing apparatus connected to an image forming apparatus, comprising: an intermediate process tray which receives sheets delivered from the image forming apparatus; a process unit which applies a predetermined process for the sheet stack received on the intermediate process tray; a pair of rollers which nips and delivers the sheets as a sheet stack subjected to the predetermined process by the process unit; a stack tray which receives the sheet stack delivered by the pair of rollers; and a controller which positions one roller of the pair of rollers to a first standby position, after a last sheet of the sheet stack is delivered onto the intermediate process tray and while the process unit applies the predetermined process, so that the one roller of the pair of rollers does not contact the sheet stack in the first standby position; wherein the first standby position corresponds to a thickness of the sheet stack to be delivered onto the stack tray; wherein the controller causes the one roller of the pair of rollers to contact the sheet stack after the process unit applies the predetermined process; and wherein until the last sheet of the sheet stack is delivered onto the intermediate process tray the controller positions the one roller of the pair of rollers to a second standby position where an opening amount of the pair of rollers is larger than that the one of the pair of rollers is in the first standby position.