| 摘要 |
<p>PURPOSE:To prevent malfunction due to disturbing light by projecting light from a light emitting body on a photo detection part continuously by a body of revolution, etc., with a slit. CONSTITUTION:Light emitting body 7 and photo detector 8 are arranged with tape 6 interposed. Light emitting body 7 is inserted into reference pin 9 and then fixed. Reference pin 9, having slit 9a formed, revolves on light emitting body 7 through pulley 10 fixed under pin 9 and belt 12 as capstan 5 rotates. At the time of the opaque magnetic surface of tape 6, no light reaches photo detector 8. At the time of its transparent leader tape, intermittent light is detected by photo detector 8 and then converted into an electric signal and band-pass filter 2o filters only its electric signal, thereby performing automatic stop and reversing operations through mechanism control circuit 22. Here, an electric signal generated due to disturbing light is cut off. Therefore, malfunction caused by disturbing light can be prevented.</p> |
