Abstract: A temperature control device with high accuracy and stability comprising a heating device and a cooling device which are controlled by separate control circuits for performing proportional control, integral control, derivative control and the like. A ratio of energy supply periods to predetermined control periods is thereby varied, on the basis of a controlled variable calculated from direction, size, change velocity and the like of deviation of actual temperature of a controlled medium from desired set temperature so as to control heating and cooling energy supplies for the heating and cooling devices. The heating energy and cooling energy supplies for the heating and cooling devices can be separately controlled by means of different proportional bands.

Abstract: A method of controlling an injection molding machine wherein a purging operation for changing a raw material resin, a warming up operation for warming up the machine until a condition at which a mass producing operation can be started are preset, and metal mold temperatures corresponding to successive operations and metal mold temperatures corresponding to successive purging and warming up operations are preset so as to successively perform the purging and warming up operations and then begin the mass producing operation, characterized in that at the time of restarting the injection molding machine, after removal a trouble which caused a temporal pause of the operation of the machine, a pause time and the metal mold temperature are detected from the warming up operation corresponding to the set mold temperature, the restarting being commenced in accordance with the set metal mold temperatures which vary depending upon a length of the pause time.