Patent ID: 8104861

Claim:
A method for aligning image planes in a multiple print-head system, wherein each print-head has an associated image plane, the method comprising the steps of: (a) defining a test pattern having marks 1 , 3 and 5 at three intended locations a, c and e in a first image plane associated with a first printhead in which the location c is aligned to a first axis of the image plane relative to the location a, and the location e is aligned at a first predetermined distance between the locations a and b and offset from the axis by a second predetermined distance along a second axis of the image plane; (b) further defining the test pattern with a mark 4 at an intended location d in the second image plane associated with a second printhead such that the location d of the second image plane corresponds to a position aligned along a first axis with one of the mark locations a, b and c and aligned along the second axis, but not aligned along the first axis, with a second one of the mark locations a, b and c; (c) printing the test pattern using the multiple print-head system on the test media; (d) using an imaging detector to capture an image of the printed test pattern; (e) determining detected locations a′, c′, and e′ of the printed marks 1 , 3 , and 5 in the first image plane and detected location d′ of printed mark 4 in the second image plane in the printed test pattern; (f) determining deviation of the detected location d′ of the mark 4 of the second image plane relative to the detected locations a′, b′ and c′ of the marks 1 , 3 , and 5 of the first image plane from the captured image.