To provide a heating element incorporating a safety device, which can monitor with precision abnormalities of all portions of the heating element, of the one constituted so as to maintain a given temperature range with a temperature control device or a self-temperature control function.
By constituting the heating element with a heating resistor element 4 and a flat protective resistor element 5 thermally linked with the heating resistor element and electrically connected in series having a large figure number of change of resistance values by positive resistance temperature characteristics, a state of even surface heating is shifted to a state of linear voltage-centered heating when the heating resistor element generates heat exceeding the normal heating temperature, when, the resistance value of the protective resistor element 5 gets far larger than that of the heating resistor element 4 to greatly restrain current of the series connection circuit, substantially putting the heating resistor element in a state of suspension.
OBARA KAZUYUKI
YONEYAMA MITSURU
ISHII TAKAHITO
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