An image forming device comprising a fixing unit for thermally fixing a developer on a recording sheet, a control unit that controls the temperature to maintain the fixing unit at one of a fixing temperature and a stand-by temperature lower than the fixing temperature, and a transport unit that transports the recording sheet to the fixing unit, wherein, when the temperature of the fixing unit has dropped from the fixing temperature to the stand-by temperature, and a printing command is received, the control unit controls the transport unit so as to set a stand-by time to wait before starting to transport the recording sheet after the printing command is received as a second time interval, which is longer than a first time interval of time required for the temperature of the fixing unit to reach the fixing temperature based on information relating to the current temperature of the fixing unit.