An image forming apparatus is provided. The image forming apparatus includes a fuser configured to fuse a print sheet on which toner is developed and a fuser driver configured to supply a heating element of the fuser with a power source supplied from an external alternating current (AC) so as to enable the fuser to have a preset target temperature. The fuser driver performs a control of the number of waveforms hours of an AC power source supplied to the heating element by varying a control cycle according to a temperature of the fuser.