Sheet processing apparatus, image forming apparatus and sheet buffering device that maintain alignment of sheets of sheet bundle

摘要

A sheet processing apparatus capable of maintaining alignment of sheets of a sheet bundle on a processing tray even in a job uses sheets including particular sheets. In the sheet processing apparatus (finisher), a sheet conveyed along a conveying path is retained in a buffer path. The sheet and the following sheet are stacked on a processing tray in a state superposed with a shift in a conveying direction. A finisher controller determines in advance, before a conveyed sheet reaches the buffer path, whether or not the sheet is a particular sheet having a protrusion. When the sheet retained in the buffer path and the following sheet are to be superposed one upon the other, the amount of the shift between the sheets in the conveying direction is controlled according to a result of the determination by the finisher controller.