PURPOSE: To eliminate a switch dedicated for detection of opening/closing and to realize the cost down of component simple substance and the improvement of assembling capability by detecting the opening/closing of a recording paper cover by an image reading part.

CONSTITUTION: Data light L read by a CCD 19 is printed out on roll paper (recording paper) 22 at a plotter part comprised of a thermal head 20 and a platen roller 21. A roll paper cover (recording paper cover) 23 opened and closed when the roll paper is exchanged, etc., is provided as a cover or main body armor at the upper part of a housing part in which the roll paper 22 is housed. An actuator 24 blocks or passes the data light L from a light irradiation area by interlocking with the opening/closing of the roll paper cover 23. The CCD 19 detects the opening/closing of the roll paper cover 23 in accordance with the presence/absence of the data light L by the actuator 24.