Ultrasonic wave sensor and image forming apparatus

摘要

A sensor is attached to an apparatus having a fixing unit which fixes an image on a recording medium by heating the recording medium. The sensor includes: a transmission unit transmitting an ultrasonic wave to the recording medium; a reception unit receiving the ultrasonic wave via the recording medium, and output a signal corresponding to the received ultrasonic wave; and a detecting unit detecting information relating to a state of the recording medium which has changed by passing through the fixing unit, based on a first signal which the reception unit has output upon having received the ultrasonic wave before the recording medium has passed through the fixing unit, and a second signal which the reception unit has output upon having received the ultrasonic wave after the recording medium has passed through the fixing unit.

主权项

1. A sensor to be attached to an apparatus having a fixing unit which fixes an image on a recording medium by heating the recording medium, the sensor comprising:
a transmission unit configured to transmit an ultrasonic wave to the recording medium; a reception unit configured to receive the ultrasonic wave via the recording medium, and output a signal corresponding to the received ultrasonic wave; and a detecting unit configured to detect information relating to an amount of moisture which the recording medium contained prior to passing through the fixing unit or information relating to change in temperature of the recording medium due to having passed through the fixing unit, based on a first signal which the reception unit has output upon having received the ultrasonic wave before the recording medium has passed through the fixing unit, and a second signal which the reception unit has output upon having received the ultrasonic after the recording medium has passed through the fixing unit.