Sheet processing apparatus and image forming apparatus

A sheet processing apparatus that crimp-binds a sheet bundle by pressurizing the sheet bundle from front and back sides of the sheet bundle, comprising:

• a plurality of pressure tooth parts that has a concave-convex surface to pressurize a predetermined crimp-binding range of the sheet bundle and sequentially pressurizes the predetermined crimp-binding range in a direction crossing a pressurizing direction;
• a receiving tooth part that has a concave-convex surface to pressurize the predetermined crimp-binding range of the sheet bundle and is disposed opposite to the plurality of pressure tooth parts so as to receive pressure from the plurality of pressure tooth parts;
• a drive part moving the plurality of pressure tooth parts and the receiving tooth part such that a distance between each of the plurality of pressure tooth parts and the receiving tooth part is reduced to crimp-bind each other;
• a moving part moving the plurality of pressure tooth parts and the receiving tooth part, along one side of the sheet bundle, to binding positions in which a binding process is performed;
• and
• a control unit controlling the drive part and the moving part,
• wherein the control unit controls the plurality of pressure tooth parts to sequentially pressurize divided portions in which the predetermined crimp-binding range is divided in the direction crossing the pressurizing direction of the plurality of pressure tooth parts, at the binding positions.