| 摘要 |
PURPOSE:To securely use a device in supply voltage in a wide range by changing a setting area according to the supply voltage in a device which decides the abnormality of a heating means in case of detecting a numerical value different from the specified set area by digitizing the thermal characteristic of a heating device. CONSTITUTION:A voltage detection circuit 2 detects the voltage of a power source 1 and transmits it to a CPU 3. An electric heater 5 installed in a heating fixing unit 10 is connected to the power source 1 through a heater control circuit 4 and made to heat according to the signal of the CPU 3. When the application of current to the electric heater 5 is continuously executed for specific time, T seconds or above, for example, it is decided that abnormality occurs in the heating device and the application of current to the electric heater 5 is stopped. And an abnormality detection means like software which displays a warning is provided and the current applying time constant T is made to be changed according to the used supply voltage. Thus, an image forming device which can be used in the supply voltage in wide range and whose security is high can be obtained. |
