Patent ID: 7950643

Claim:
A sheet finisher comprising: a saddle-stitching unit configured to stitch a center of a sheet bundle; a folding unit configured to fold the center and to form a fold; first and second rollers that move along a direction of the fold while nipping and pressing the fold of the sheet bundle conveyed from the folding unit and reinforce the fold; and a drive section configured to move the first and second rollers along the direction of the fold from a standby position apart from an edge of the sheet bundle, wherein the first and second rollers are separate from each other in a thickness direction of the sheet bundle at the standby position, and after the first and second rollers reach a position where the first and second rollers pass the edge of the sheet bundle of a processable maximum size, the first and second rollers come close to each other in the thickness direction and nip the fold.