Heating unit, method of manufacturing the same, fixing apparatus, and electrophotographic image forming apparatus using the fixing apparatus

A method of manufacturing a heating unit for a fixing apparatus, the method comprising:

• preparing a support member having a recess;
• disposing current-supply electrodes respectively at both ends of a length of the recess;
• filling the recess with a solution in which a polymer precursor and an electrically-conductive filler are distributed;
• and
• by hardening the polymer precursor through a heat treatment process, forming a heating element including a base polymer and an electrically-conductive filler distributed in the base polymer to form an electrically-conductive network in a base polymer, in the recess.

A fixing apparatus comprising:

• a endless belt which is rotatable and flexible;
• a back-up member which is disposed outside the endless belt and moves the endless belt;
• and
• a heating unit which is located inside the endless belt to face the back-up member and form a fixing nip, and heats the endless belt at the fixing nip,
• wherein the heating unit comprises
• a support member in which a recess is provided at a location corresponding to the fixing nip;
• and
• a heater which comprises current-supply electrodes respectively disposed at both ends of a length of the recess, and a heating element which is formed in the recess to contact the current-supply electrodes, the heater including a base polymer and an electrically-conductive filler distributed in the base polymer to form an electrically-conductive network in a base polymer.