SYSTEM AND METHOD FOR SENSING A PAPER ROLL ULTRASONICALLY

摘要

A system includes an ultrasonic transducer positioned to be in contact with the outer surface of a paper roll. The system further includes a transmitter circuit and a receiver circuit in communication with the ultrasonic transducer. The transmitter circuit provides a transmit signal to the ultrasonic transducer for generating an ultrasonic signal, which is transmitted into the paper roll. The receiver circuit provides a received signal indicative of an ultrasonic return echo from the paper roll. The ultrasonic return echo resulting from the ultrasonic signal interacting with the paper roll. The system also includes a processor circuit for determining an amount (length or diameter of roll) of paper remaining on the paper roll in response to the transmit signal and the receive signal. The processor provides an output signal when the amount of paper remaining falls below a threshold. A method of sensing paper on a paper roll is also presented. The method includes transmitting an ultrasonic signal into a paper roll and detecting an ultrasonic return echo from the paper roll. The ultrasonic return echo resulting from the ultrasonic signal interacting with the paper roll. The method further includes determining an amount of paper remaining on the paper roll in response to the ultrasonic return echo transmit signal.