Patent ID: 7922164

Claim:
A sheet finishing device comprising: an aligning unit that collects a recording sheet on which an image forming unit has formed an image and aligns rear end of the recording sheet, the aligning unit having a sheet supporting surface that is shorter in length than a length of the recording sheet in a conveying direction; and a collecting tray in which the recording sheet aligned by the aligning unit is collected, the collecting tray including a fixed collecting member that collects and houses the recording sheet in a bottom portion thereof having a level difference in the conveying direction with respect to the sheet supporting surface of the aligning unit; and a movable supporting member that is rotatably attached to an intermediate portion of the fixed collecting member along the conveying direction by a base member such that a front portion of the movable supporting member is able to move closer to or far from the recording sheet, wherein when the aligning unit collects the recording sheet, the front portion of the movable supporting member rotates toward the recording sheet and abuts against a front portion of the recording sheet to control position of the rear end of the recording sheet in the aligning unit.