Position information is formed on a recording surface of a recording medium. The position information is constructed from first line segments, which are parallel to each other, and a second line segment, which crosses the first line segments. On the basis of a distance between (i) an intersection of one of the first line segment and a scan line and (ii) an intersection of another of the first line segments and the scan line, the intersection and an intersection of the second line segment and the scan line are measured or calculated. By this, a position of a head is recognized.