Patent ID: 7578498
Filing Date: 2009-08-25
Classification: B26D,B26F,B65H,G03G,Y10T

Abstract:
1. A sheet processing apparatus comprising: a skew detecting unit configured to detect a quantity of skew at a forward edge and a quantity of skew at a rear edge of a sheet conveyed along a conveying path; a hole punching section arranged downstream from the skew detecting unit and orthogonally to the conveying path of the sheet, having a tilt angle changeable with respect to the conveying direction of the sheet, and configured to perform punching processing to the sheet that is conveyed; and a control unit configured to change the tilt angle of the hole punching section in accordance with each of the quantity of skew at the forward edge and the quantity of skew at the rear edge, carry out skew correction at the forward edge within a first correction range, and carry out skew correction at the rear edge within a second correction range that is narrower than the first correction range; wherein the control unit carries out skew correction at the forward edge by tilting the hole punching section within the second correction range, in the case where the detected quantity of skew at the forward edge is a tilt angle exceeding the second correction range, and then carries out skew correction at the rear edge by tilting the hole punching section in accordance with a difference between the quantity of skew at the forward edge after the correction and the quantity of skew at the rear edge.