Heat roller assembly for image forming apparatus

An electrophotogrphic image forming apparatus having a fixing unit and a driver rotating the fixing unit, the fixing unit having: a heat roller assembly with a heat roller, a gear cap coupled to an end of the heat roller and transmitting rotation to the heat roller, and an elastic member coupling the gear cap with the heat roller; and a pressing roller pressing a recording medium passing between the pressing roller and the heat roller toward the heat roller, the gear cap having an insertion portion inserted in the heat roller, and a gear portion integrally provided adjacent to the insertion portion and rotated by the driver, and the elastic member being provided between an outer circumferential surface of the insertion portion of the gear cap and an inner circumferential surface of the heat roller, and coupling the gear cap with the heat roller.