PURPOSE: To suppress thermal interference between both heat rollers by controlling their temperatures in a manner that the lower limit value of the surface temp. of one of the heat rollers which are pressure-contacted with each other produces a temp. difference of more than 10°C with respect to the upper limit value of the surface temp. of the other.
CONSTITUTION: In the case of controlling temperatures by mutually pressure- contacting the two heat rollers 1 which control the electric power of heaters 2 by detecting the elongation or contraction owing to the temp. change of temp. detecting bars 10 by means of detecting pieces 12 and controlling switches 9, the temperatures are so set that the lower limit value of the surface temp. of one heat roller produces a temp. difference of more than 10°C with respect to the upper limit value of the surface temp. of the other heat roller, whereby the mutual thermal interference of both heat rollers may be prevented and the abnormal temp. rise of the roller surfaces may be prevented. Since one end of the bar 10 is fixed by means of screws, the rate of projection on the free end side may be set freely, and the temperatures of the heat rollers 1 may be selected freely.
IMADA EIJI
KATOU SHIYOUSHICHI
