Folded portion flattening device, post treatment apparatus and image forming apparatus

摘要

A folded portion flattening device has: a sheet conveying section that conveys a booklet of folded sheets in a predetermined conveyance direction with a folded portion ahead; a sheet stopper that stops the booklet conveyed by the sheet conveying section at a fixed position; a pair of booklet holding members that hold the booklet stopped by the sheet stopper by gripping the booklet at both faces of the booklet; a pressing member that presses the front end of the folded portion of the booklet held by the booklet holding members in an opposite direction to the conveyance direction, so that a curve at the front end of the folded portion is flattened to form a flat face; and a wrinkle preventing member that prevents wrinkle from being generated in the flat face when pressed by the pressing member.