<p>A pair of registration rollers (5) align a leading edge of a recording medium (T) having a transparent section (T1) and a non-transparent section (T2). A boundary sensor (73) detects a boundary between the transparent section (T1) and the non-transparent section (T2). The boundary sensor (73) is provided on a downstream side of a direction of conveying the recording medium (T) by the registration rollers (5).</p>
