Power supply device and image forming apparatus

An image forming apparatus comprising:

• a transfer unit configured to transfer a toner image to a sheet;
• and
• a fixing unit including a heater and a power supply device, and configured to fix, to the sheet, the toner image transferred to the sheet by the transfer unit, with use of heat generated by the heater;
• wherein the power supply device includes:
• a first circuit connected to a predetermined power source;
• the first circuit including:
• the heater;
• an adjustment unit configured to adjust electric power to be supplied from the predetermined power source to the heater;
• a first controller configured to control the adjustment unit;
• a first detector configured to detect a parameter about electric power supplied to the heater;
• and
• a first communication unit connected to the first controller;
• a second circuit insulated from the first circuit, the second circuit including:
• a second communication unit insulated from the first communication unit, and configured to perform wireless communication with the first communication unit;
• and
• a second controller connected to the second communication unit;
• and
• a discriminator configured to discriminate whether the first circuit is in an abnormal state or not;
• and
• a second detector configured to detect a temperature of the heater,
• wherein the first controller is operated by electric power supplied thereto by a voltage generated in the first communication unit due to a voltage output from the second controller to the second communication unit,
• wherein the first controller transmits information about a result of detection by the first detector to the second controller by the wireless communication,
• wherein the second controller supplies, to the first controller via the first communication unit and the second communication unit, a first signal for reducing a deviation between a target temperature of the heater and the temperature detected by the second detector based on the information transmitted from the first controller to the second controller,
• wherein the first controller controls the adjustment unit based on the first signal, and
• wherein, in a case where the temperature detected by the second detector is higher discriminator discriminates that the first circuit is in the abnormal state, supplying of the electric power to the first controller is blocked off.