| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a residual quantity detection device and the like which can detect the residual quantity of a recording medium wound around a medium roll as the length of the recording medium.SOLUTION: An ultrasonic transducer 32 transmits and receives an ultrasonic wave in a radial direction toward and from the center of a tape roll 24. A distance measurement part 51 measures propagation time from transmission to reception of the ultrasonic wave and measures the separation distance from the ultrasonic transducer 32 to the outermost surface of the tape roll 24 on the basis of the measured propagation time. A length calculation part 52 calculates the residual length of a printing tape 22 in the tape roll 24 on the basis of the measured separation distance, the diameter of a tape core 21 and the thickness of the printing tape 22.</p> |
