Method of multi-color pagewide printing with optimized nozzle hydration

A method of multi-color printing in a single pass using a fixed pagewide array of monochrome inkjet printheads, the printheads being aligned with each other in a media feed direction, the method comprising the steps of:

• feeding print media along the media feed direction past a first printhead positioned furthest upstream in the array, a third printhead downstream of the first printhead and a second printhead positioned furthest downstream in the array;
• printing a yellow ink onto the print media using the first printhead;
• printing a black ink onto the print media using the third printhead;
• and
• printing a cyan or magenta ink onto the print media using the second printhead,
• wherein:
• each of the first, second and third printheads prints a respective keep-wet pattern onto print media;
• each keep-wet pattern is defined by a plurality of dots printed at a frequency sufficient to maintain hydration of each nozzle of a respective printhead;
• all nozzles of the first printhead print a first keep-wet pattern at a first average frequency, all nozzles of the second printhead print a second keep-wet pattern at a second average frequency, and all nozzles of the third printhead print a third keep-wet pattern at a third average frequency;
• and
• the first average frequency is higher than the third average frequency.