RECORDING MEDIUM DETERMINATION APPARATUS AND IMAGE FORMING APPARATUS

摘要

The recording medium determination apparatus includes a transmission unit for transmitting an ultrasonic wave, a receiving unit for outputting a signal corresponding to the ultrasonic wave, a peak extraction unit for detecting a value of the signal output from the receiving unit, a control unit for determining basis weight of a recording medium based on the value of the signal, and a timer for measuring a period of time from when the transmission unit transmits the ultrasonic wave to the detection by the peak extraction unit. The control unit calculates, based on a period of time measured by the timer at the time of factory shipment and a period of time measured by the timer after the factory shipment, variation of a distance between the transmission unit and the receiving unit after the factory shipment.

主权项

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; and 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, wherein the control unit is configured to calculate, based on a period of time measured by the measurement unit in a first condition and a period of time measured by the measurement unit in a second condition different from the first condition, 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.