Patent ID: 7216863

Claim:
A sheet processing apparatus mountable on an upper surface of an image forming apparatus which forms an image on a sheet, comprising: a first sheet stacking portion, which temporarily stacks sheets discharged from said image forming apparatus; an alignment member, which supports and aligns the sheets discharged on said first sheet stacking portion, movable in a direction perpendicular to the sheet discharging direction; a sheet processing unit which performs a predetermined process on the sheets stacked and aligned on said first sheet stacking portion; and a second sheet stacking portion which receives the sheets from said first sheet stacking portion, wherein said second sheet stacking portion is located substantially vertically below said first sheet stacking portion, wherein said alignment member drops the supported sheets to said second sheet stacking portion by movement of said alignment member in the direction apart from the supported sheets, and wherein the sheet processing apparatus is mounted on the upper surface of the image forming apparatus and is substantially within an area of installation of the image forming apparatus.