Patent ID: 9429892
Filing Date: 2016-08-30
CPC Classification: G03G

Claim Text:
1. A recording medium determination apparatus, comprising: a transmission unit configured to transmit an ultrasonic wave; a receiving unit configured to receive an ultrasonic wave transmitted from the transmission unit via a recording medium and output a first signal according to the received ultrasonic wave, and receive an ultrasonic wave transmitted from the transmission unit not via the recording medium and output a second signal according to the received ultrasonic wave; a detection unit configured to detect a value of the first signal and a value of the second signal output from the receiving unit; a control unit configured to determine basis weight of the recording medium based on the value of the first signal detected by the detection unit; a measurement unit configured to measure a period of time from when the transmission unit transmits the ultrasonic wave to when the detection unit detects the value of the second signal; and a moving unit configured to move between an opening position in which an inside of the recording medium determination apparatus is opened and a closing position in which the inside of the recording medium determination apparatus is closed, wherein the transmission unit or the receiving unit moves according to movement of the moving unit, wherein the control unit is configured to calculate, based on a reference period of time in a first condition in which the moving unit is at the closing position and a period of time measured by the measurement unit in a second condition in which the moving unit moves from the closing position to the opening position and from the opening position to the closing position at least one time after the first condition, a variation of a distance between the transmission unit and the receiving unit from the first condition to the second condition, to thereby determine the basis weight of the recording medium in accordance with the calculated variation of the distance and the value of the first signal.