Patent ID: 6991225

Claim:
A sheet process device comprising: first stack means for stacking thereon sheets discharged from an image forming apparatus; second stack means for stacking thereon the sheets transferred from said first stack means; a transfer unit for transferring the sheets as a sheaf of sheets from said first stack means to said second stack means; and transfer control means for controlling, in a case where a size of the sheet discharged to said first stack means is equal to or smaller than a predetermined size, said transfer unit to transfer the sheets as the sheaf of sheets from said first stack means to said second stack means every time a first predetermined number of sheets are stacked on said first stack means, and for controlling, in a case where the size of the sheet discharged to said first stack means is larger than the predetermined size, said transfer unit to transfer the sheets as the sheaf of sheets from said first stack means to said second stack means in response to that a second predetermined number of sheets are stacked on said first stack means, wherein the second predetermined number is smaller than the first predetermined number.