Patent ID: 8141863

Claim:
A sheet processing apparatus, comprising: a sheet aligning part that accumulates and aligns sheets so as to generate a bundle of sheets; an edge stitching processor that performs an edge stitching process by which the bundle of sheets generated in the sheet aligning part is stitched together at one edge of the bundle of sheets; an apparatus housing that includes an opening portion through which the bundle of sheets is discharged to an outside of the apparatus housing; a saddle stitching processor that performs, outside of the apparatus housing, a saddle stitching process by which the bundle of sheets discharged through the opening portion is stitched together at a center portion of the bundle of sheets in a transporting direction of the bundle of sheets; and a stacking tray that is provided below the opening portion and outside the apparatus housing, and on which the bundle of sheets subjected to the edge stitching process in the edge stitching processor is capable of being stacked, and the bundle of sheets subjected to the saddle stitching process in the saddle stitching processor is also capable of being stacked, wherein when the bundle of sheets subjected to the edge stitching process in the edge stitching processor is discharged through the opening portion and stacked on the stacking tray, the saddle stitching processor is retracted so as not to interfere with the stacking of the bundle of sheets and wherein the saddle stitching processor is disposed to a stitching position on a transport path for the bundle of sheets when performing the saddle stitching process and the saddle stitching processor moves from the stitching position in a direction perpendicular to the transporting direction of the bundle of sheets being discharged through the opening portion when the bundle of sheets is to be stacked on the stacking tray upon the completion of the saddle stitching process.