Patent ID: 8690143

Claim:
A post-processing device, comprising: a processing tray on which sheets are to be stacked; a transport portion for transporting, toward the processing tray, a sheet introduced through an introduction port; a delivery mechanism for delivering the sheets stacked on the processing tray to a delivery tray on a boundary between copies; a turn-aside portion for turning aside the sheet to delay arrival of the sheet at the processing tray, and then sending out the sheet to the processing tray; and a control portion, wherein, when a remaining number of sheets of one copy unstacked on the processing tray exceeds a maximum number of stacked sheets that is an amount of sheets stackable on the processing tray, the control portion makes the delivery mechanism deliver a sheet bundle corresponding to the one copy a plurality of times so as to avoid delivery of only one sheet on a last page of the one copy, and the control portion makes the transport portion transport toward the turn-aside portion a sheet on a first page to be stacked on the processing tray after delivering the sheet bundle so that the turn-aside portion turns aside the sheet on the first page to be stacked on the processing tray after delivering the sheet bundle in order to delay arrival of the sheet at the processing tray and then send out the sheet that has been turned aside to the processing tray.