Sheet processing apparatus and image forming apparatus having the same

An image forming apparatus, comprising:

• an image forming device which forms an image on a sheet;
• a conveying portion which conveys sheets;
• a conveying path which is a path for sheets conveyed by the conveying portion;
• a stack portion on which sheets discharged from a discharging port of the conveying path by the conveying portion in a conveying direction are stacked;
• a first binding portion which moves in a crossing direction crossing to the conveying direction so that the first binding portion moves from a first side of the sheet processing apparatus to a second side of the sheet processing apparatus and moves from the second side to the first side;
• a first regulating portion which regulates a position of a sheet bundle, stacked on the stack portion, in the crossing direction by contacting an end of the first side of the sheet bundle in the crossing direction and moves in the crossing direction;
• a second regulating portion which regulates a position of a sheet bundle, stacked on the stack portion, in the crossing direction by contacting an end of the second side of the sheet bundle in the crossing direction and moves in the crossing direction;
• a third regulating portion which regulates a position of a sheet bundle, stacked on the stack portion, in the conveying direction by contacting an upstream end of the sheet bundle in the conveying direction;
• and
• a second binding portion which binds a corner portion of a sheet bundle without a staple, the corner portion including an end where the first regulating portion has contacted and an end where the third regulating portion has contacted, the corner portion being on the first side of the sheet bundle,
• wherein the first binding portion binds a corner portion of a sheet bundle by a staple, the corner portion including an end where the first regulating portion has contacted and an end where the third regulating portion has contacted, the corner portion being on the first side of the sheet bundle,
• an upstream end of a sheet bundle in the conveying direction when the upstream end of the sheet bundle is bound by the second binding portion is located at a downstream side relative to an upstream end of a sheet bundle in the conveying direction when the upstream end of the sheet bundle is bound by the first binding portion, and
• the first regulating portion includes a contact portion which contacts a sheet bundle on the stack portion, and
• a binding position where the second binding portion binds a sheet bundle on the stack portion is located upstream, in the conveying direction, of an upstream end of the contact portion in the conveying direction.