| 摘要 |
PROBLEM TO BE SOLVED: To improve maintenance performance by instantly judging the cause of faulty of temp. detecting means by providing a means capable of judging as first faulty when resistance value of the temp. detecting means is lower than the first resisting value, and judging as the second faulty when the resistance value of the temp. detecting means is higher than the second resisting value. SOLUTION: This image forming device is composed so as to output rectangular waves from an oscillation circuit 401, and when the output (point B) is H, switches 402 and 405 are turned on, while the switches 403 and 404 are turned off, a resistor 407 is connected between a thermistor 410 and a grounding, and a voltage on the grounding side as the one side of the thermistor 410 is input to a COMP 409 as comparing means. When the output of the oscillation circuit 401 is L, the resistor 408 is connected between the thermistor 410 and the high voltage side by turning on the switches 403 and 404, and turning off the switches 402 and 405, while the voltage of the high voltage side as the other side of the thermistor 410 is input to the COMP 409 as the comparing means. A state of the former is judged as the first faulty (abnormal heating-up), and the state of the latter as the second faulty (discontinuity). |
