Patent ID: 8196923

Claim:
A sheet processing apparatus comprising: a sheet-conveying unit configured to convey a sheet in a sheet-conveying direction; a conveying path through which a sheet conveyed by the sheet-conveying unit is conveyed; a skew-correcting member having a contacting portion that contacts with an end of the sheet conveyed and configured to correct skew of the sheet by contacting the end of the sheet, the skew-correcting member is movable so that the contacting portion moves along the conveying path in the sheet-conveying direction; a rotatable puncher, provided between the sheet-conveying unit and the skew-correcting member, configured to punch the sheet, a driving unit configured to move the skew-correcting member so that the contacting portion of the skew-correcting member contacts the end of the sheet being conveyed in the sheet conveying direction by the sheet-conveying unit, and the driving unit moves the contacting portion of the skew-correcting member along the conveying path in the sheet-conveying direction at a speed that is different from a sheet-conveying speed of the sheet-conveying unit in a state in which the contacting portion of the skew correcting member contacts the end of sheet being conveyed in the sheet conveying direction, and wherein the rotary puncher punches the sheet contacting the contacting portion of the skew-correcting member moved by the driving unit.