Binding apparatus and image forming apparatus

An image forming apparatus comprising a binding apparatus that binds a sheet bundle, the binding apparatus comprising:

• an accumulating unit where a plurality of sheets having an area that serves as a binding margin is to be accumulated as the sheet bundle, in which toner is fixed onto all of, or a part of, the area;
• a pressure unit that sandwiches the binding margin of the sheet bundle stacked on the accumulating unit therebetween and applies a pressure to the binding margin;
• and
• a heating unit that heats the toner on the binding margin that is receiving the pressure applied by the pressure unit, wherein
• the pressure unit is configured to apply the pressure to the binding margin while forming a plurality of grooves and ridges in the binding margin in a direction in which the pressure is applied.