| 摘要 |
PURPOSE:To reduce a space occupied by a sensor, by a method wherein a detecting means, outputting a speed signal in accordance with the passing speed of respective slits of a slit plate only during a period when the slit plate, provided on a carrier, is detected, is provided in the title detector. CONSTITUTION:When light beams, generated by a light emission diode D1, are intercepted by the upper area UA of a slit plate 16, the potential of the collector of a phototransistor Tr1 becomes a H-level. When the light beams, generated by the light emission diode D2, are intercepted intermittently by the lower area LA of the slit plate 16, in which slits 16a are formed, the potential of the collector of the phototransistor Tr1 becomes H-level intermittently. The output terminal of an AND gate 18 becomes H-level intermittently in accordance with the intermittent H-level of the potential of the collector of the phototransistor Tr1 whereby the ON/OFF operations of the transistor Tr2 may be effected with a period in accordance with the moving speed of the slit plate 16. |
