Patent ID: 8727331

Claim:
An image forming apparatus comprising: an image forming unit configured to formed an image on a sheet; a sheet conveyance unit configured to convey a sheet formed by the image forming unit; a sheet stacking unit configured to stack a plurality of sheets conveyed by the sheet conveyance unit; a post-processing unit configured to perform post-processing for a sheet bundle including the plurality of sheets stacked by the sheet stacking unit; a buffer unit arranged upstream of the sheet stacking unit and configured to perform a buffer processing that retains one or more sheets and to overlay the one or more sheets retained and a succeeding sheet; an acquisition unit configured to acquire sheet information for determining whether a sheet is inhibited from the buffer processing by the buffer unit; and a control unit configured to control, based on the sheet information of an (N+1)th sheet, the buffer unit regarding whether the buffer unit should retain an Nth sheet, in a case where an Nth sheet is not inhibited from the buffer processing by the buffer unit.