| 摘要 |
PURPOSE:To arbitrarily alter the relative position of a recording medium and an optical sensor by placing one or a plurality of sensors on a printing carrier, and laterally tracing on the medium controlled to be conveyed under the carrier to arbitrarily set it at a recording position. CONSTITUTION:The position of a printed line is specified by an optical sensor 13 for optically detecting the printed line 14 of a medium 1 to be introduced into an apparatus by rollers 3-3', the medium 1 is conveyed toward a position to be updated and printed with it as a reference, and updated and printed by a printing head 8. The sensor placed on a printing head carrier can be laterally moved on the medium 1 in a direction of an arrow. That is, it is so controlled as to stop at a specific character row of the printed line 14 on the medium 1, and the printed line can be detected by a spot sensor 12 by conveying the medium 1 via the rollers 3-3'. |
