INJECTION DEVICE OF INJECTION MOLDING MACHINE

摘要

PROBLEM TO BE SOLVED: To provide an inline type plunger type injection device capable of preventing the back flow of molten resin in a measuring step and an injection filling step without complicating the structure.SOLUTION: The injection device of an injection molding machine comprises: a heating cylinder 15; a screw rotatably arranged in the heating cylinder 15; a plunger 17 arranged at the hollow part of the screw 16 coaxially rotatably with the screw 16 an also movably to the axial direction; a flight 17a formed in the prescribed range of the outer circumferential face on the injection nozzle side of the plunger 17; a check ring 18 arranged at the injection nozzle side of the plunger 17; a first resin flow passage 10 formed between the inner circumferential face of the heating cylinder 15 and the outer circumferential face of the screw 16; and a communication resin flow passage 11 communicating the resin flow passage 10 with the outer circumferential face of the plunger 17 at which the flight 17a is formed in a measuring step.