Patent ID: 6450607
Filing Date: 2002-09-17
Classification: B41J

Abstract:
A method for aligning multiple color inkjet printheads to provide ink droplet placement within about {fraction (1/600)} inch of a desired droplet location which comprises:providing an ink jet printer containing a printhead carriage for retaining a black ink printhead and a multi-color ink printhead thereon, the black ink printhead containing a black ink pen and the color ink printhead containing at least two pens for providing ink droplets on a print media; setting the carriage to an initial first position with respect to a first swath direction across the print media; moving the carriage across the print media in the first swath direction with respect to the initial first position, while depositing ink droplets from a first color ink pen to provide a series of first vertical line segments across a width of the print media, each of the first vertical line segments being spaced a first constant separation distance from a previously printed first vertical line segment, and while depositing ink droplets from a second color ink pen to provide a series of second vertical line segments across the print media, each of the second vertical line segments being spaced a second constant separation distance from a previously printed second vertical line segment, the first and second series of vertical line segments providing a first alignment pattern; resetting the carriage to the initial first position with respect to the first swath direction across the print media; moving the carriage across the print media in the first swath direction with respect to the initial first position, while depositing ink droplets from the first color ink pen to provide a series of third vertical line segments across a width of the print media, each of the third vertical line segments being spaced a first constant separation distance from a previously printed third vertical line segment; moving the carriage across the print media in the first swath direction from an initial second position, while depositing ink droplets from the black ink pen to provide a series of fourth vertical line segments across the print media, each of the fourth vertical line segments being spaced a fourth constant separation distance from a previously printed fourth vertical line segment; the third and fourth series of vertical line segments providing a second alignment pattern; visually inspecting the printed vertical line segments of the first alignment pattern; selecting a set of line segments from the first alignment pattern which are in substantial horizontal alignment with one another; selecting a set of line segments from the second alignment pattern which are in substantial horizontal alignment with one another; and providing the selected set of line segments from the first and second alignment patterns to a substantially permanent printer memory location.