Image forming apparatus

An image forming apparatus comprising:

• an image forming unit that forms an image on a printing medium;
• a fuser that has a heating unit to which an alternating voltage is applied from an alternating power supply so as to perform heating, the fuser thermally fixing the image that is formed on the printing medium by the image forming unit;
• a zero-cross pulse generating unit that generates a zero-cross pulse in accordance with a period when an absolute value of the alternating voltage is less than a predetermined value;
• a voltage estimating unit that estimates the alternating voltage on the basis of a width of the zero-cross pulse generated by the zero-cross pulse generating unit;
• a temperature detecting unit that detects the temperature of the fuser;
• an operation control unit that controls the heating unit until the temperature detected by the temperature detecting unit reaches a regulation temperature by applying the alternating voltage from the alternating power supply to the heating unit when the image forming apparatus is activated;
• a time-out time setting unit that sets a time-out time related to the control of the operation control unit on the basis of the alternating voltage estimated by the voltage estimating unit;
• and
• a fixation abnormality determining unit that determines abnormalities in the fuser when the temperature detected by the temperature detecting unit does not reach the regulation temperature after the operation control unit starts the control of the heating unit and the time-out time set by the time-out time setting unit has elapsed.