| 摘要 |
<p>PURPOSE:To detect the beginning and/or the end of a magnetic tape wound around one pair of reels by using an optical signal giving and receiving means consisting of one set of light emitting element and a light receiving element. CONSTITUTION:A hub part 6a of a supply reel 6 is formed with a material for transmitting light emitted from the light emitting element 40, and moreover, the supply reel 6 is rotatively supported by fitting a rotary driving body 30 into a hole 6a1 of an inner circumferential part of the hub part 6a. A reel engagement member 35 of the rotary driving body 30 is formed with a reflecting surface 35b, providing a function of changing directions of an optical path of the light from the light emitting element 40. Then, the light emitting element 40 is arranged outside flange parts 6b and 6c of the supply reel 6, while the light receiving element 41 is fixed to a chassis 21 fitted with the rotary driving body 30. Then, when the magnetic tape is not wound around the hub part 6a, the light from the light emitting element 40 is transmitted through the hub part 6a and received by the light receiving element 41 via the reflecting surface 35b of the reel engagement member 35.</p> |
