Print cartridge alignment in paper axis

[54] PRINT CARTRIDGE ALIGNMENT IN PAPER AXIS

[75] Inventors: Robert D. Haselby, San Diego, Calif.;

Michael A. Nguyen, Singapore,
Singapore

[73] Assignee: Hewlett-Packard Company, Palo
Alto, Calif.

[21] Appl. No.: 785,650

[22] Filed: Oct. 31,1991

[51] Int. CI.' B41J 2/01; B41J 25/308

[52] U.S. CI 346/1.1; 346/139 R;

346/140 R; 400/59; 400/82

[58] Field of Search 346/1.1, 140 R, 139 C,

346/139 R; 400/82, 323, 55, 59; 395/105, 108,

104

[56] References Cited

U.S. PATENT DOCUMENTS

4,626,867 12/1986 Furukawaetal 346/1.1

4,916,638 4/1990 Haselby et al 364/519

FOREIGN PATENT DOCUMENTS

0145159 8/1984 Japan 346/140 R

0027270 2/1986 Japan 400/82

62-227757 10/1987 Japan 400/323

0290567 12/1987 Japan 400/82

OTHER PUBLICATIONS "Print Registration Test for Bidirectional Printer" IBM

Apparatus and techniques are disclosed for aligning the operation of the ink jet printhead cartridges of a multiple printhead ink jet swath printer that includes a print carriage that is movable along a horizontal carriage scan axis, (b) first and second ink jet printhead cartridges supported by the movable carriage for printing onto a print media that is selectively movable along a vertical media scan axis, and (c) an optical sensor supported by the movable carriage. Alignment of the operation of the printheads along the media scan axis is performed by determining with the optical sensor the relative positions of horizontal test line segments printed by selected nozzles of the printhead cartridges. The relative position information is utilized to calculate a vertical alignment correction which is implemented by enabling selected ink jet nozzles of the printheads and adjusting the position of one printhead cartridge relative to the other such that the nozzles of the ink jet printheads are properly spaced along the media scan axis.

11 Claims, 22 Drawing Sheets