SHEET PROCESSING APPARATUS AND IMAGE FORMING APPARATUS HAVING THE SAME

A sheet processing apparatus includes a conveying portion， a stack portion on which sheets are stacked， a first binding portion moving in a crossing direction crossing a conveying direction， a first regulating portion regulating a position of a sheet bundle stacked on the stack portion in the crossing direction， a first rack moving in the crossing direction with the first regulating portion， a first pinion forming a rack-pinion mechanism with the first rack， a second regulating portion regulating a position of a sheet bundle stacked on the stack portion in the crossing direction， a second rack moving in the crossing direction with the second regulating portion， a second pinion forming another rack-pinion mechanism with the second rack， a third regulating portion regulating a position of a sheet bundle stacked on the stack portion， and a second binding portion which binds a corner portion of a sheet bundle without a staple.