Patent ID: 8721025

Claim:
A computer-implemented method of measuring spatial characteristics of an inkjet printer, said method comprising the steps of: printing groups of marks in accordance with a first predetermined pattern on a print medium using a first group of nozzles of a print mechanism of the printer to form a first printed pattern; printing groups of marks in accordance with a second predetermined pattern on the print medium using a second group of nozzles of the print mechanism of the printer to form a second printed pattern, wherein the printed groups of marks in the first printed pattern and second printed pattern form a test chart and a region of overlap of the printed groups of marks in accordance with the first and second printed patterns are formed on the print medium; imaging at least a portion of the printed test chart having the groups of marks printed thereon to form an image of the printed test chart; selecting from the image of the printed test chart in the region of overlap a first group of marks from the first printed pattern and a second group of marks from the second printed pattern; for each of the first and second groups of marks, determining a position representative of that group printed on the print medium; and determining an offset for measuring spatial characteristics of the printer between the first and second printed patterns dependent upon the representative position of each of the first and second groups of marks, wherein the offset is a displacement between patterns in the test chart and the image of the printed test chart.