Image forming apparatus and control method therefor

An image forming apparatus that operates by an electric power supplied from a commercial power source, the image forming apparatus comprising:

• a fixing unit adapted to fix a toner image transferred onto a sheet;
• a voltage detection unit adapted to detect an input voltage of the commercial power source;
• a setting unit adapted to set a fixing electric power supplied to said fixing unit from the commercial power source;
• and
• a control unit adapted to:
• suspend an operation of the image forming apparatus when the fixing electric power set by said setting unit is less than a predetermined electric power and when the input voltage detected by said voltage detection unit is less than a first voltage;
• and
• continue supply of power to said fixing unit while reducing the fixing electric power set by said setting unit when the fixing electric power set by said setting unit is not less than the predetermined electric power and when the input voltage detected by said voltage detection unit is less than a second voltage.