Patent ID: 7067078

Claim:
A control method of an injection molding machine, comprising the steps of: a) setting a range of an accumulating hydraulic pressure that is a hydraulic pressure of oil accumulated in an accumulator and is supplied to an actuator in order to actuate the actuator; b) supplying oil from a hydraulic supply source at a certain amount and a certain pressure; c) detecting an actuating hydraulic pressure that is a hydraulic pressure of oil actuating the actuator and the accumulating hydraulic pressure; d) determining whether or not the detected accumulating hydraulic pressure is sufficiently higher than the detected actuating hydraulic pressure; and e) reducing the accumulating hydraulic pressure range in a case where the detected accumulating hydraulic pressure is sufficiently higher than the detected actuating hydraulic pressure, wherein the accumulating hydraulic pressure is controlled in the range defined by an on-setting pressure for making the accumulator control part ON and an off-setting pressure for making the accumulator control part OFF.