Patent ID: 6875960

Claim:
A heating system comprising: a main heating element generating heat by supplying an electric power and having a heating surface for heating an object; a plurality of auxiliary heating elements generating heat by supplying an electric power, said auxiliary heating elements being stacked with respect to said main heating element so as to oppose only a peripheral portion of said main heating element in the stacked direction, and also being positioned centrosymmetrically with respect to the center of said main heating element; a main power source for supplying said electric power to said main heating element; an auxiliary power source for supplying said electric power to said auxiliary heating elements; and a power source controller for controlling said electric power supplied to said main heating element and said electric power supplied to said auxiliary heating elements respectively and independently, wherein said electric power supplied from said main power source to said main heating element is controlled by said controller within a first power range, said electric power supplied from said auxiliary power source to said auxiliary heating elements is controlled by said controller within a second power range, and said second power range has a width smaller than that of said first power range so as to control temperature distribution on said heating surface.