Patent ID: 8534660

Claim:
A sheet processing apparatus that forms folding lines at a set position of a sheet after image formation and outputs the sheet, the apparatus comprising: a contact unit with which a tip end or a rear end of the conveyed sheet comes into contact and by which a deflection is formed at a middle part of the sheet; folding units that form the folding lines by conveying the middle part of the sheet, at which the deflection is formed by the contact unit, between the folding units; and a deflection controlling unit that controls the deflection at the middle part of the sheet formed by the contact unit, wherein a conveyance path is formed between the contact unit and the folding units, wherein the deflection controlling unit is provided to the conveyance path, and includes a pair of elastic substances extending in a conveyance direction of the sheet, the pair of elastic substances have a smooth front surface and are provided on the conveyance path having a set space in which the sheet is conveyed between the contact unit and the folding units, and wherein the pair of elastic substances are provided such that an interval between the pair of elastic substances gets smaller from an upstream side to a downstream side of the conveyance path.