Patent ID: 7784897

Claim:
A method of measuring print accuracy of a print mechanism of a printer, the method comprising the steps of: printing a chart on a print medium using said print mechanism, said chart comprising: at least a first and a second region printed using first and second sets of nozzles respectively, said first and second sets of nozzles being a predetermined distance apart; and at least a third region printed using said first set of nozzles, wherein the printing of said first and second regions, and the printing of said third region, are separated by a print medium advance operation, and each region comprising a spread spectrum pattern; imaging said chart to form a chart image; determining the positions of said regions appearing in said chart image; and calculating the accuracy of the print mechanism of the printer using said predetermined distance, the distance in the direction of said print medium advance operation between said first and second regions, and the distance in the direction of said print medium advance operation between said first and third regions.