Sheet processing device

Abstract

In a sheet processing device in the form of an offset stacker, a sheet fence ( 103, 104 ) is provided on a side of sheets (S) to be processed stacked on a stack tray ( 3 ) opposite from a jogger ( 101, 102 ) so that the sheet fence accurately defines a final offset position of the sheets. Thereby, even when a transient offset position at which the sheets are stacked on the stack tray varies from one sheet to another, the side edges of sheets selected for offset stacking can be lined up without fail owing to the jogging action of the jogger and the supporting action of the sheet fence. A pair of joggers may be arranged on either side of the sheets, along with a pair of corresponding sheets fences on the opposing sides. The jogger and sheet fence on a same side may be supported by a common moveable frame ( 107, 108 ) so that the jogging action and sheet fence adjustment can be achieved by a common structure and a common drive unit.

1 . A sheet processing device for transporting sheets having first side edges and second side edge in a sheet transporting direction and stacking the sheets on a stack tray selectively at a regular position and at least one transversely offset position, comprising:
 an offset transport unit configured to eject sheets onto the stack tray selectively at the regular position and a first transitional offset position which is more transversely offset than a first final offset position;   a first jogger provided on a first side of the stack tray to jog the first side edges of first selected sheets; and   a first sheet fence provided on a second side of the stack tray to support the second side edges of the first selected sheets;   wherein the first sheet fence is positioned to support the first selected sheets at the first final offset position when the first side edges are jogged by the first jogger.   
     
     
         2 . The sheet processing device according to  claim 1 , further comprising a second jogger provided on the second side of the stack tray to jog the second side edges of second selected sheets; and
 a second sheet fence provided on the first side of the stack tray to support the first side edges of the second selected sheets;   wherein the offset transport unit is additionally configured to eject sheets to a second transitional offset position which is more transversely offset than a second first final offset position, the second final offset position being offset from the regular position opposite to the first final offset position; and   the second sheet fence is positioned to support the second selected sheets at the second final offset position when the second side edges are jogged by the second jogger.   
     
     
         3 . The sheet processing device according to  claim 2 , wherein the second jogger is located transversely further away from the sheets than the first sheet fence, and the first jogger is located transversely further away from the sheets than the second sheet fence, the first and second sheet fences being configured to be raised selectively so as not to interfere with transportation of sheets to the stack tray. 
     
     
         4 . The sheet processing device according to  claim 3 , wherein the first and second sheet fences comprise fence members each provided with an upper end pivotally supported by a moveable frame and a free end that can be placed on a sheet stack of the stack tray, each fence member extending obliquely downward in a downstream direction. 
     
     
         5 . The sheet processing device according to  claim 2 , wherein the first jogger and second sheet fence are both attached to a first moveable frame configured to be moved transversely with respect to the sheet transporting direction to effect a jogging movement of the first jogger and to adjustably define the second final offset position; and
 the second jogger and first sheet fence are both attached to a second moveable frame configured to be moved transversely with respect to the sheet transporting direction to effect a jogging movement of the second jogger and to adjustably define the first final offset position.