Patent ID: 8459630

Claim:
A sheet processing apparatus comprising a processing portion which moves along a spine of a folded sheet bundle while pressing the spine of the folded sheet bundle to deform the spine into a square shape, wherein the processing portion includes: a first rotary member which moves along the spine of the folded sheet bundle while rotating, and nips the folded sheet bundle such that the spine of the folded sheet bundle projects by a predetermined amount from an end in an axial direction of the first rotary member; a pressing rotary member which (i) is provided corresponding to the first rotary member in a moving direction of the processing portion when the processing portion performs a deforming process on the spine, (ii) moves along the spine of the folded sheet bundle while rotating, and (iii) presses the spine projecting from the end in the axial direction of the first rotary member; and a second rotary member which (i) is provided downstream of the first rotary member in the moving direction of the processing portion, (ii) moves along the spine of the folded sheet bundle while rotating, and (iii) nips the folded sheet bundle including the spine, wherein the end of the first rotary member from which the spine projects is displaced, in the axial direction, relative to a corresponding end of the second rotary member.