| 摘要 |
PROBLEM TO BE SOLVED: To increase surge resistance quantity of an element and improve reliability by making distribution of the rush current in the element uniform and reducing thermally repeating stress due to the rush current, in a negative resistance thermistor which is inserted, in series with a circuit, in order to reduce a rush current of a halogen lamp used in a fixing device of a laser printer or the like, using thermal fusion fixing toner. SOLUTION: A shape of a thermistor electrode 102 of a thermistor is made into a doughnut shape or a rectangular structure, whose central part is eliminated, or the electrode is made into a multilayered structure. Shape of some layers in the multilayered structure is made into doughnut shape or rectangular structure, whose central part has been removed. It is also possible that the electrode is made a structure where a central part of the electrode is thinned, thereby distribution of increase of the internal temperature of a negative resistor 101 is made uniform, the density of current which is caused by local temperature increase is prevented, and improvement of surge endurance and reliability is enabled.
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