Patent ID: 8287066

Claim:
A method for maintaining a plurality of ink jets used in a printing apparatus that forms a selected ink image on a print medium by relatively moving the plurality of ink jets and the print medium in a process direction while ink drops are ejected by the plurality of ink jets, the printing apparatus forming a selected ink image in response to selected image data specifying the deposition of ink dots at selected predetermined pixel locations on a plurality of image scanlines aligned with and extending in the process direction a predetermined image length on the print medium, the method comprising the steps of: (a) constructing purge image data that specifies the deposition of at least one ink dot on at least one predetermined pixel location on each of the plurality of image scanlines within the predetermined image length; (b) storing the purge image data in a purge image memory accessible by the printing apparatus; (c) receiving selected image data specifying a selected ink image; (d) logically combining the purge image data and the selected image data to create print image data that specifies the deposition of ink dots at every predetermined pixel location based on the purge image data or the selected image data; (e) printing the print image data on the print medium and wherein the print medium has an average base optical density, the purge image data specifies a printed purge image of substantially uniformly distributed ink dots along and among the image scanlines, and the printed purge image has an average purge image optical density less than about 0.01 OD above the print medium average base optical density.