| 摘要 |
PROBLEM TO BE SOLVED: To provide a double feed detection method capable of enhancing the double feed detection accuracy while simplifying and miniaturizing a circuit. SOLUTION: In a double feed detection device, an ultrasonic transmitter 2 and an ultrasonic receiver 3 are arranged across a conveying passage of a sheet-like member. When the ultrasonic outgoing pulse signal is received by the ultrasonic transmitter 2, the ultrasonic wave is transmitted, and when the sheet-like member is present between the ultrasonic transmitter 2 and the ultrasonic receiver 3, the ultrasonic wave transmitted through the sheet-like member is received by the ultrasonic receiver 3. Reference numeral 4 denotes a control means, which feed the pulse signal of 200 kHz to a driving means 5. Reference numeral 5 denotes a driving means for driving the ultrasonic transmitter 2. The driving means 5 has an intensity control means 50 for controlling the intensity of the pulse signal according to the pulse number of the pulse signal fed from the control means 4. More specifically, the intensity control means 50 amplifies stepwise the amplitude of the ultrasonic pulse signal to be output according to the pulse number of the pulse signal fed from the control means 4. COPYRIGHT: (C)2008,JPO&INPIT
|
