| 摘要 |
PROBLEM TO BE SOLVED: To detect the presence or absence of a recording medium without using a mechanical switch by controlling the light emitting operation of an optical means, inputting a light receiving signal by linking with the control operation and judging the present or absence of the recording medium based on the intensity of lights. SOLUTION: The MCU 14a of a control part 14 confirms whether a magnetic recording and reproducing device 1 is in executing a recording operation or a reproduction operation or the like not by an internal memory 14h. When the device does not execute the recording operation or the reproduction operation, plural lights are made to be emitted from an optical unit 82 by driving a light emitting part 82a with a laser driver 14g. When reflected lights are present, the light receiving part 82b of the unit 82 outputs a light receiving signal having the intensity in accordance with the intensity of the reflected lights to the MCU 41a, which judges the presence or absence of an FD 50 by the intensity of the light receiving signal from the light receiving part 82b while referring the preliminarily recorded table between the intensity of the light received signal and the intensity of reflected lights based on the light receiving intensity.
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