Patent ID: 8678369

Claim:
A skew correction device for aligning a booklet that is a folded bundle of sheets on a conveying path, the skew correction device comprising: a first member against which a leading end of the booklet abuts in a conveying direction, the first member being configured to project in the conveying direction; a second member configured to push a trailing end of the booklet in the conveying direction so that the leading end of the booklet abuts against the first member; a deflection generating member including a lower surface and upper surface between which the booklet is conveyed, the deflection generating member configured to provide a deflection force along at least a center portion of the booklet with respect to the conveying direction for an entity of the booklet's travel in the conveying direction toward the first member to deflect the center portion of the booklet downward when the trailing end is pushed toward the first member; and a processor configured to, set a distance between the lower surface and the upper surface of the deflection generating member to a first distance, when the second member pushes the trailing end of the booklet in the conveying direction, the first distance being a distance that provides a minimal frictional force sufficient to convey the booklet, the first distance being determined based on a thickness of the booklet, stop the sheet from being conveyed in the conveying direction and set the distance between the lower surface and the upper surface to a second distance, when the leading end of the booklet reaches a desired distance short of the first member, the second distance being less than the first distance and such that the frictional force is increased to a level that forces the sheets to align upon further movement in the conveying direction, and set the distance between the lower surface and the upper surface to a third distance, when the leading end of the booklet abuts against the first member, the third distance being less than the second distance such that the booklet is compressed after the booklet abuts against the first member.