Apparatus and method to control temperature of heating roller used in fusing device of image forming apparatus

An apparatus to control the temperature of a heating roller used in a fusing device of an image forming apparatus, the apparatus comprising:

• the heating roller that generates heat to melt toner attached to a printing medium;
• a first induction coil that is disposed outside the heating roller and heats the heating roller by using induced current generated according to current flowing through the first induction coil;
• two second induction coils that are disposed at upper portions of both ends of the first induction coil and heat the heating roller by using induced current generated according to current flowing through the two second induction coils;
• a power supply unit that supplies current to the first induction coil and the two second induction coils;
• and
• a control unit configured to control the power supply unit to supply current flowing in the same direction to the first induction coil and the second induction coils or in a different direction to the first induction coil with respect to the second induction coils according to the size of paper fed into the heating roller,
• wherein, if the size of paper fed into the heating roller is less than a preset size, the control unit controls the power supply unit to supply current flowing in different directions to the first induction coil and the second induction coil so that the direction in which the current flows through the first induction coil is opposite to the direction in which the current flows through the second induction coils.