| 摘要 |
PROBLEM TO BE SOLVED: To provide a printer in which ejecting position of dot can be corrected during scanning motion. SOLUTION: PPS variation (53) along a scan axis (17) is found by shining (20, 20', 20") a light beam (22, 22', 22") from pen carriage to (d<SB>1</SB>) print-medium position (15) and back (d<SB>1</SB>) to detector (21, 21'), and applying a pathlength/ intensity correlation (44). Sensing is done while scanning (17), to find relative PPS profile (53) along the track. With no medium in place (Fig. 4) this measures mechanical imperfections- and can be corrected by later deducting thickness (42) of a medium. If medium is present (Fig. 5), adjustment is omitted. For absolute values a plural-lamp (20', 20") sensor is calibrated for each lamp, at the PPS design point (Fig. 7). Pagewide/webwide variants are included. COPYRIGHT: (C)2003,JPO
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