Patent ID: 8662488

Claim:
A post-processing device comprising: a staple-less binding unit that forms a cut in a sheet stack and cuts a part of the sheet stack into a predetermined shape to form a tongue portion in the sheet stack, the tongue portion having a part where one end part of the tongue portion is not separated from the sheet stack, and binds the sheet stack by bending the tongue portion and inserting the other end part of the tongue portion into the cut; and a sheet stack transport unit that transports the sheet stack, wherein the binding unit binds an end portion of the sheet stack which is perpendicular to the sheet stack transport direction such that the one end part of the tongue portion in the sheet stack bound by the binding unit is on a upstream side of the other end part of the tongue portion in the sheet stack transport direction, wherein the binding unit comprises a cut forming unit and a tongue portion forming unit, and wherein the tongue portion forming unit is disposed on a downstream side in the sheet stack transport direction with respect to the cut forming unit.