Patent ID: 6312082
Filing Date: 2001-11-06
Classification: B41J

Abstract:
A method for determining positional correction factors for at least one ink-jet clear fluid writing instrument and at least one ink-jet colorant writing instrument respectively mounted for printing on an adjacently positioned print medium and using a predetermined pattern of printing, the method comprising:mounting the ink-jet clear fluid writing instrument and ink-jet colorant writing instrument in predetermined fixed positions relative to each other for printing pixels on the adjacently positioned print medium;mounting an optical sensing device in a predetermined fixed position relative to the ink-jet clear fluid writing instrument and ink-jet colorant writing instrument;printing a first predetermined pattern in predetermined target regions on a blank print medium by firing from one writing instrument;printing a second predetermined pattern on the print medium by firing from the other writing instrument such that first regions of print occur superjacent the first predetermined pattern and second regions of print occur substantially adjacent the first regions such that the first regions wherein the first and second regions have differences in reflectivity recognizable by the optical sensing device;sensing the first regions and the second regions with the optical sensing device to obtain data representative of the differences in reflectivity;determining positional difference between the first regions and the second regions compared to predetermined target regions positions of the first predetermined pattern; andscanning the ink-jet clear fluid writing instrument across the print medium and firing clear fluid droplets toward predetermined target pixels to form a pattern of a series of positional-calibration indicia.