SLIT PLATE FOR OPTICAL POSITION DETECTION SENSOR

摘要

PURPOSE:To enhance the detection accuracy of the position of a printing unit by enhancing dust preventing effect in the slit plate used in an optical position detection sensor for controlling the printing position of a dot type printer. CONSTITUTION:An optical position detection sensor is equipped with a slit plate 31 moved in a first direction in synchronous relation to a printing unit and a fixed detection part. The slit plate 31 is constituted by parallelly providing a large number of fine slits 33 to a thin plate 32 in the first direction and providing a dust accumulating recessed part 34 to the thin plate 32. The detection part detects the slits 33 of the slit plate 31 when the slit plate 31 is moved through the detection part and the recessed part 34 is formed to the part shifted from the detection part.