Patent ID: 6494558
Filing Date: 2002-12-17
Classification: B41J

Abstract:
An incremental printer for forming an image on a printing medium; said printer comprising:plural printheads each marking a swath on such medium to cooperatively form an image portion, each head being subject to directional error that alters its swath length; first portions of at least one processor operating each head to print swaths of a test pattern onto such medium; an optical sensor reading the test pattern; second portions of at least one processor analyzing sensor signals to measure, for each head, two values: the swath length, and relative spacing of the swaths; and said second processor portions also comparing, for each head, the swath length against the relative spacing, to find the directional error for that head; and said second processor portions also comparing, for at least one head, the directional error against a predetermined limit representing a selected coarsest-acceptable line-length accuracy.