Sheet processing apparatus and image forming system

An image forming system comprising:

• an image forming apparatus configured to form an image on a sheet;
• and
• a sheet processing apparatus configured to stitch a bundle of sheets, on which an image is formed by the image forming apparatus,
• the sheet processing apparatus including
• a sheet stacker configured to stack thereon multiple sheets;
• a staple-containing stitching unit configured to stitch the sheets using one or more staples;
• a staple-free stitching unit configured to stitch the sheets without using a staple;
• a first drive source configured to drive the staple-containing stitching unit;
• a second drive source separate from the first drive source and configured to drive the staple-free stitching unit;
• a frame including at least a first frame member and a second frame member respectively disposed outside both ends of the sheet stacker in a direction perpendicular to a sheet conveying direction in which the sheets enter the sheet stacker, the first frame member being disposed on a side where the staple-containing stitching unit is disposed, the second frame member being disposed on a side where the staple-free stitching unit is disposed, and the second frame member including a hole section;
• and
• an outer cover including at least a first cover member and a second cover member respectively disposed further outside the first and second frame members in the direction perpendicular to the sheet conveying direction, wherein
• the staple-free stitching unit is disposed on a back side of the sheet processing apparatus, and the staple-containing stitching unit is disposed on a front side of the sheet processing apparatus,
• at least a part of the first cover member is openable and closable, and at least a part of the second cover member is detachable, and
• the staple-free stitching unit located between the second frame and the second cover member when the staple-free stitching unit stands by at a home position.