Patent ID: 7922161

Claim:
A sheet finisher comprising: a saddle stitch unit configured to stitch a center of a sheet bundle, in which printed sheets are bundled, with a staple; a fold unit configured to fold the center stitched by the saddle stitch unit to form a fold line; a roller unit that includes a reinforce roller for reinforcing the fold line and moves along a direction of the fold line while applying pressure by the reinforce roller to the fold line of the sheet bundle transported from the fold unit; a drive unit configured to move the roller unit along the direction of the fold line; and a control unit configured to control a movement speed of the roller unit, the control unit causing the roller unit to move at a first speed in an outside of a specified range including the edge of the staple, and causing the roller unit to move at a second speed not higher than the first speed in the specified range including the edge of the staple, the second speed being set to decrease a difference between the second speed and the first speed when the sheet bundle is thick, and the second speed being set to increase the difference between the second speed and the first speed when the sheet bundle is thin.