Patent ID: 8894057

Claim:
A sheet processing apparatus comprising: a sheet transport unit configured to transport a sheet; a sheet sensing unit including two or more sensors, each of the sensors being configured to sense the sheet, disposed in a widthwise direction of the sheet intersecting a sheet transport direction by the sheet transport unit; a driving unit configured to move said sheet sensing unit in the widthwise direction; a drive force transmission unit configured to transmit a driving force of said driving unit to said sheet sensing unit; and a position deviation detecting unit configured to detect a position deviation amount of the sheet in the widthwise direction based on a moving distance of said sheet sensing unit through said driving unit until at least one of the two or more sensors senses the sheet, wherein said position deviation detecting unit invalidates a sensing result of the sheet by the at least one of the two or more sensors of said sheet sensing unit from when said driving unit starts driving until said sheet sensing unit moves by a predetermined distance, and determines the position deviation amount of the sheet using a detection result of the sheet after said sheet sensing unit moves by the predetermined distance.