Patent ID: 7191655
Filing Date: 2007-03-20
Classification: G01N

Abstract:
1. A material determination system, comprising: an oscillator adapted to generate an alternating signal while repeatedly varying a freguency over a freguency band in the range of 40 kHz to 100 kHz; a modulator adapted to output a rectangular wave signal using an output signal from said oscillator; a driver adapted to amplify the output signal from said modulator and output an amplified signal; an ultrasonic transducer including a transmitter and a receiver, said transmitter adapted to transmit the amplified signal over a predetermined frequency band toward a plurality of sheets of paper, and said receiver for adapted to receive reflected signals from said plurality of sheets of paper; an amplifier that amplifies an output signal from said receiver; a wave-shaping circuit that shapes said amplified output signal into a binary signal; a counter that measures an elapsed time between a start signal and said binary signal, said elapsed time corresponding to a distance to said plurality of sheets of paper; a distance detection section adapted to receive said elapsed time from said counter, said distance detection section adapted to detect a quantity of said sheets of paper based on said elapsed time; a material database for storing information that represents a reception signal on a material basis; and material determination device for defining a type of paper by its material based on the information stored in the material database and the signals received by the ultrasonic transducer.