Patent ID: 8191882

Claim:
A spine formation device comprising: a sheet conveyer that conveys a bundle of folded sheets with a folded portion of the bundle of folded sheets forming a front end portion of the bundle of folded sheets; a pressing unit disposed downstream from the sheet conveyer in a sheet conveyance direction in which the sheet conveyer conveys the bundle of folded sheets, the pressing unit including a first pressing member movable according to a pressing load applied thereto in a pressing direction perpendicular to the sheet conveyance direction to press opposed sides of the front end portion of the bundle of folded sheets conveyed with the sheet conveyer, and a second pressing member attached to the first pressing member and disposed closer to the bundle of folded sheets than the first pressing member, to press the front end portion of the bundle of folded sheets, the second pressing member movable in the sheet conveyance direction in conjunction with movement of the first pressing member; and a spine formation member disposed downstream from the pressing unit in the sheet conveyance direction at a predetermined distance from the pressing unit, the spine formation member including a contact surface against which the folded portion of the bundle of folded sheets is pressed with a predetermined spine-forming load to form a spine of the bundle of folded sheets with the second pressing member in conjunction with the first pressing member moving in the pressing direction wherein each of the first pressing member and the second pressing member comprises an oblique contact surface oblique to the pressing direction of the first pressing member, and the first pressing member and the second pressing member are in sliding contact with each other at the oblique contact surface of the first pressing member.