Sheet processing apparatus, method for detecting lateral position deviation amount of sheet, and image forming system

A method of detecting a lateral position deviation amount of a sheet in a sheet processing apparatus comprising a sheet transport unit configured to transport a sheet in a sheet transport direction, 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 the sheet transport direction, a driving unit configured to move said sheet sensing unit in the widthwise direction, and a drive force transmission unit configured to transmit a driving force of said driving unit to said sheet sensing unit,

• the method comprising:
• a moving step of moving said sheet sensing unit using said driving unit and said drive force transmission unit;
• and
• a detecting step of, in a case where at least one of the two or more sensors senses the sheet from when said driving means starts driving until said sheet sensing unit moves by a predetermined distance, invalidating a sensing result of the sheet by the at least one of the two or more sensors of said sheet sensing unit and detecting a position deviation amount of the sheet in the widthwise direction based on a moving distance of said sheet sensing unit until the other sensor of two or more sensor detects the sheet after the sheet sensing unit moves by the predetermined distance.

An image forming system including

• an image forming apparatus configured to form an image on a sheet, and
• 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 detection result of the sheet by said sheet sensing unit in the widthwise direction 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.