| 摘要 |
PURPOSE:To detect the passage of an article surely without limiting the form and the quality of the article, by detecting the article by an acoustic pulse reflective detector in an optical reader where the radiation of light beams is controlled by the signal from a device for detection of the passage of the article. CONSTITUTION:An article 1 is moved in the direction of an arrow. An acoustic pulse reflective detector consists of wave transmitters 20a and 21a and wave receivers 20b and 21b. When the article 1 comes near that part above the line connecting the wave transmitter 20a (21a) and the wave receiver 20b (21b), acoustic pulses are reflected and reach the wave receiver 20b (21b). In this case, the article is always surely detected without limiting its shape and quality. |
