Patent ID: 6478401
Filing Date: 2002-11-12
Classification: B41J

Abstract:
In a printer including first and second print heads mounted for movement across a paper path along a defined horizontal axis, a method for determining vertical misalignment between the print heads along a defined vertical axis which extends substantially perpendicular to the horizontal axis, the method comprising the steps of:(a) printing a test pattern of first and second alternating slanted blocks extending horizontally across a media, the first and second slanted blocks slanted relative to both the horizontal axis and the vertical axis, each first slanted block printed by the first print head and each second slanted block printed by the second print head, a known edge angle of the first and second slanted blocks being substantially the same; (b) moving a sensor horizontally over the test pattern and producing an output signal therefrom; (c) identifying edges of each first slanted block and each second slanted block based upon the sensor output signal; and (d) determining vertical misalignment of the first and second print heads based upon the edges identified in step (c), the known edge angle, and a known horizontal misalignment of the first and second print heads.