Fusing device, image forming apparatus having the same, and control method thereof

An induction heating type fusing device to reduce the size of an induction coil and an image forming apparatus having the same, and a control method thereof. The image forming apparatus includes a printing device to form an image on a recording medium, and a fusing device to fix the image to the recording medium. The fusing device includes a heating member arranged to transfer heat to the recording medium and having a main heater and a sub heater, and an induction coil having a width equal to or less than a width of the recording medium and arranged in an axial direction of the heating member to generate a magnetic field acting on the main heater. The sub heater is arranged inside the heating member to heat both ends of the main heater.