MOLD MONITORING DEVICE OF INJECTION MOLDER

PURPOSE:To prevent the detection performance of a device from deteriorating due to external noise by a method wherein the lights emitted from light emitting elements provided in the interior of the control unit main body of a molder are applied on a mold and the resultant thrown lights are received by optical fibers and lead to light receiving elements provided in the interior of the control unit main body of the molder. CONSTITUTION:After the opening of a mold 30, by successively putting a plurality of light emitting elements 21, 21,... within the control unit main body of a molder into actuation, the light signals of the elements are transmitted through optical fibers 24, 24,..., fiber connectors 26a and 26b to optical fibers 27, 27,... in order to be thrown from the tips of optical fibers 27a, 27a,... If any residual molded items present i the mold, the lights from the optical fibers 27a, 27a,... are shielded and do not enter opposing optical fibers 28a, 28a,... and consequently no light receiving signals from light receiving elements 22, 22,... are outputted. When the residual molded items are detected in the above-mentioned manner, a monitoring control circuit 23 circuits a signal to stop the following mold clamping, and at the same time an alarm signal in outputted.