Patent ID: 8170463

Claim:
A sheet processing apparatus comprising: a sheet stacking portion on which sheets are stacked; a conveying portion which conveys a sheet onto the sheet stacking portion; a reference wall against which an upstream end portion in a sheet conveying direction of the sheet, conveyed onto the sheet stacking portion, is abutted; a first restriction member which has a first restriction portion crossing the reference wall, the first restriction portion preventing lift of the upstream end portion of the sheet stacked on the sheet stacking portion; and a second restriction member which has a second restriction portion located downstream of the reference wall, the second restriction portion preventing lift of the upstream end portion of the sheet stacked on the sheet stacking portion, wherein each of the first restriction member and the second restriction member is moveable, by a pushing force of a sheet being conveyed, between respective restricting positions in which the lift of the upstream end portion of the sheet stacked on the sheet stacking portion is prevented and respective retracting positions to which each restriction member is retracted from each restricting position, wherein the second restriction member moves from the restricting position to the retracting position after the first restriction member moves from the restricting position to the retracting position as the sheet is introduced to the sheet stacking portion, and wherein each of the first restriction member and the second restriction member moves from each retracting position to each restricting position as the sheet passes.