| 摘要 |
PURPOSE:To generate an alarm when the counted value of the operation of a frame or frame-group key reaches a prescribed value, and to prevent malfunction of retrieval, by counting the operation of the advance key when retrieving a desired information frame or frame group on a microfilm. CONSTITUTION:Frame marks MK or subject marks MC provided corresponding various information frames K and information groups of a microfilm 1 are detected by a frame mark detector 67 and a subject mark detector 68, and detection signals from those detectors 67 and 68 are counted by a film control circuit to retrieve a desired information frame K and information frame group of the film 1. When the counted value of the control circuit reaches a maximum countable value, the film is advanced by one frame with a +1 frame key 14 and by one subject with a +1 subject key 22. During this operation, if a malfunction deciding means 101 which inputs the output of a counter 100 counting frame mark and subject mark signals detects malfunction, a movement inhibition signal is outputted to the retrieval control circuit and a buzzer 97 sounds for warning. |
