After the front end area of the print medium has been printed and when the printing is to be continued following the front end area, a preliminary ejection is performed, prior to the current scan, on the nozzles that have not been used in preceding scans but begin to be used in a current scan, in order...http://www.google.com.au/patents/US6871934?utm_source=gb-gplus-sharePatent US6871934 - Ink jet print head and ink jet printing apparatus
