Patent ID: 7976000

Claim:
A sheet stacking apparatus, comprising: first and second guide plates each having an inclined guide surface and forming a gap therebetween, the gap at an open state of the guide plates having a first spacing, the gap at a closed state of the guide plates having a second spacing narrower than the first spacing; a sheet take-in portion disposed under the first and second guide plates to support sheets dropped from the guide surfaces, a leading edge of the sheets in a conveying direction being directed downward when the sheets are supported by the sheet take-in portion; a sheet conveying path configured to convey the sheets downward from above, curving at a position where the sheets are guided by the guide surfaces, and configured to curve the sheets together with the guide surfaces; and a controller configured to permit the first and second guide plates to enter the closed state and guide additional sheets by the guide surface thereof, the additional sheets being conveyed following the sheets supported by the sheet take-in portion, and then to enter the open state and drop the additional sheets through the gap onto the sheets supported by the sheet take-in portion.