US Patent 7604315 Method for maintaining printhead performance

A method of operating an ink jet apparatus to print a print job on print media with a printhead having a supply of ink and an initial printhead operating frequency is disclosed. The method comprises receiving the print job for printing on the media, determining the volume of the supply of ink, comparing the volume of the supply of ink to a predetermined level, calculating a revised printhead operating frequency in response to the comparison, and operating the printhead at the revised printhead operating frequency to print the print job.