In an imaging device for forming a visible image on a recording medium by pressurizing the recording medium, provided are means for detecting a certain position of the recording medium to be pressurized before the recording medium is pressurized, and means for controlling timing of beginning and stopping to pressurize the recording medium based upon a result of the detecting operation.Thus, the recording medium is accurately begun to pressurize at the leading end and stopped to pressurize at the trailing end regardless of a variation of a travelling speed for the recording medium.