| 摘要 |
<p>PURPOSE:To stop the head of a magnetic tape at a specific position by running a magnetic tape in a normal direction when the leader part provided to the head of the magnetic tape is detected while the magnetic tape travels in the reverse direction, and stopping its run when the boundary between the magnetic tape and leader part reaches a detection position. CONSTITUTION:A hole into which a light emitting element is inserted is formed at a position a little close to the opening part in the middle of reels 2S and 2T of a cassette 1, and the transparent leader tape is provided at least to the head part of a tape 3. Then, light emitted by the light emitting element 30 inserted into the hole is photodetected by a photodetector 31 through a transparent window provided to the leader tape and a side wall of the cassette 1. Therefore, when the boundary o the magnetic tape 3 and leader tape reaches an alternate long and short dash line connecting the light emitting element 30 and a photodetector 31, that is detected. Further, when the leader tape 3L reaches an optical path, that is detected by the photodetector 31 to generate a tape top signal, which is supplied to the interruption terminal of a microcomputer 41 which performs system control.</p> |
