If the printhead sits inactive for a period of time, ink may dry in the nozzles. Printing may not remove these ink plugs from the nozzles. White streaks appear in printed text or graphic. To improve print quality, these ink plugs need to be forced out or purged. A purge print routine is built into the printer to clear the nozzles.
To purge the nozzles:
UPDATED: June 29, 2020