Patent ID: 7637502
Filing Date: 2009-12-29
Classification: B42C,B65H

Abstract:
1. A sheet processing apparatus comprising: a stacking tray on which the sheets to be processed are stacked, and which provides a return member for aligning the stacked sheets in a sheet conveying direction and a reference wall against which rear ends of sheets in the sheet conveying direction are abutted by the return member; a discharge roller pair which discharges a sheet on the stacking tray, and which rollers can move apart from each other and close to each other; a first path in which a sheet is conveyed to the discharge roller pair, wherein a length of the first path is shorter than the length of the minimum sheet size being conveyed in the sheet conveying direction; a second path branched from the first path at a branching point and meeting with the first path at an upstream side in the sheet conveying direction of the discharge roller pair; a first conveyance roller, disposed at one end of the first path, which is disposed upstream of the branching point in the sheet conveying direction; a path switching member, disposed at the branching point, which guides a sheet selectively to the first path or the second path; and a controlling device which controls, sheet conveyance, wherein the controlling device controls so that, after a first sheet is guided into the first path by the path switching member and the front end of the first sheet is projected from the discharge roller pair, the rollers of the discharge roller pair are apart from each other and the first sheet is held in the first path, and then the path switching member is changed over and a second conveyed sheet is guided into the second path with the first sheet kept to project the front end of the first sheet from the discharge rollers, and wherein the controlling device controls, so that when the front end of the second sheet projects from the front end of the first sheet by a prescribed length, the rollers of the discharge roller pair are brought close to each other, the first and second sheets are discharged onto the stacking tray by the discharge roller pair in a state that the second sheet is superimposed on the first sheet, the front end of the second sheet leading ahead by the prescribed length from the front end of the first sheet, and the first and second sheets are aligned in the sheet conveying direction by action of the return member on the top of the second sheet; wherein the path switching member is changed over after the rear end of the first sheet has passed over the first conveyance roller.