| 摘要 |
PURPOSE:To easily measure the residual capacity of a tape by providing a light emitting/receiving part at a part where rotational discs having the same interval slits and a prescribed shape of notch interlocking with a supplying reel and a take-up reel respectively are superposed, and counting a generated pulse. CONSTITUTION:The first and the second discs 1 and 2 turn at the same speed as the supplying reel and the take-up reel respectively, and at the disc 1, radialized slits 11a-11n having equiangular intervals are provided and at the second disc 2, a notch having an angle H' which satisfies a correction value a(P) in the expression that changes up to a linear notch angle H. And by moving a light emitting element and a light receiving elements 8 and 9 corresponding to a tape position wound on the supplying reel, and counting the number of pulses resulted from the above, a counted value represents the residual capacity of the tape as it is without performing a complicated calculation. As a result, the residual capacity of the tape can be easily measured. In the expression, N(P) represents the number of pulses which change non-linearly against a tape having the radius of r(P) at the supply reel, and N'(P) represents the number of pulses which change linearly.
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