an image forming apparatus has a fixing unit that fixes a developer transferred onto a print medium . the apparatus includes a temperature detector and a movement detector . the temperature detector has a thermistor that detects a temperature of or near a fixing member . the movement detector detects that the thermistor has moved relative to the fixing member . the movement detector includes a first , second , and third electrically conductive members . the first electrically conductive member and a second electrically conductive member are connected to each other via the thermistor . the third electrically conductive member cooperates with the first electrically conductive member to form a first switch , and with the second electrically conductive member to form a second switch . when the thermistor moves out of contact engagement with the fixing member , at least one of the first switch and the second switch is closed .