| 摘要 |
<p>An injection nozzle of an injection molding machine, in which a heating unit for heating an injection nozzle body (3) projecting from the front end of a heating cylinder (1) consists of a plurality of heating elements (7, 10) provided around and extending in the lengthwise direction of the injection nozzle body (3), the temperatures of the portions of the nozzle body which are heated with these heating elements being detected (9, 11) independently, the heating elements (7, 10) being controlled independently of each other on the basis of the detected temperatures. The temperatures of various portions of the nozzle body can be controlled independently of each other to desired optimum levels. For example, the temperature of the front end portion of the nozzle body, which tends to decrease when this portion contacts a mold, can be controlled to a higher level, and the temperature of the intermediate and rear portions of the nozzle body, which tends to increase since these portions are close to the heating cylinder, to a lower level. Therefore, the trickling and threading, which are apt to occur at the front end portion of the injection nozzle, and scorching of a resin, when a single nozzle heating means is used, can be prevented, and a pressure loss of the resin passing the front end portion of the nozzle can be lessened.</p> |
