Heater having heat generating resistors

摘要

A heater apparatus includes an electrically insulative base plate and a plurality of independent resistors, extending along a length of the base plate, for producing heat upon electric energization thereof. A temperature detecting element detects a temperature of the base plate, and a controller controls a supply of electric power to the plurality of independent resistors so that the temperature detected by the detecting element approaches a predetermined temperature. A selecting device selects at least one of the resistors to be energized to change a resultant resistance of the selected resistors in accordance with an output of the detecting element.