Patent ID: 7631858

Claim:
A folded portion flattening unit comprising: a sheet conveyance unit that conveys a booklet including a folded sheet with a folded portion in a lead toward a predetermined conveyance direction; a sheet stopper that stops the booklet at a predetermined position, the booklet being conveyed by the sheet conveyance unit; a pair of booklet grasping members that clamp and grasp the booklet stopped by the sheet stopper at both faces of the booklet; a pressing member that substantially flattens a curve at a front end of the folded portion of the booklet being grasped by the booklet grasping members, by pressing the front end of the folded portion toward a direction opposite to the conveyance direction; and a grasping force adjustment unit that adjusts grasping force, the grasping force being generated by the pair of booklet grasping members when the pair of booklet grasping members grasp the booklet stopped by the sheet stopper, wherein the folded portion flattening unit is incorporated into a post-treatment device, the post-treatment device receiving the sheet that an image is formed on by an image forming apparatus connected to the folded portion flattening unit, the post-treatment device folding and delivering the sheet, the folded portion flattening unit includes a booklet information receiving unit that receives booklet information from the image forming apparatus, the booklet information forming the basis for adjusting the grasping force, and the grasping force adjustment unit adjusts the grasping force based on the booklet information received by the booklet information receiving unit, wherein the booklet information is a combination of the number of sheets, a sheet size, a sheet thickness, and a type of sheet.