Patent ID: 7431683

Claim:
A sheet bending apparatus for performing a center-folding processing to a stack of plurality of recording sheets which are placed on a sheet holding member and whose both side ends are aligned, the center-folding processing being performed by a pair of center-folding rollers and a bending blade facing each other and positioned in a vicinity of a central portion in a sheet conveyance direction of the sheet holding member, the sheet bending apparatus comprising: a pair of upper side end aligning members positioned upstream in the sheet conveyance direction on the sheet holding member and being movable equally in opposite width directions of the sheet holding member, the pair of upper side end aligning members approach from opposite width sides of the sheet placed in the sheet holding member upstream of the pair of center-folding rollers and the bending blade; a pair of lower side end aligning members positioned downstream in the sheet conveyance direction on the sheet holding member and being movable equally in opposite width directions of the sheet holding member, the pair of lower side end aligning member approach from opposite width sides of the sheet placed in the sheet holding member downstream of the pair of center-holding rollers and the bending blade; and a controller, wherein the controller performs: a first processing of making the upper side end aligning members approach a recording sheet in course of being conveyed into, the sheet holding member a predetermined distance shorter than a predetermined approaching distance; a second processing of making the upper side end aligning members approach the recording sheet placed in the sheet holding member a remainder of the approaching distance; and a third processing of making the lower side end aligning members approach the recording sheet placed in the sheet holding member a predetermined approaching distance within a period when the second processing is performed.