Each nozzle of an ink-jet head has heaters having different heating capacities, and in accordance with the heater driven, a diameter of an ink dot formed by ink which is discharged from the nozzle is changed, thereby printing a large dot or a small dot. When multi-value image data is inputted, the multi-value...http://www.google.com/patents/US6305775?utm_source=gb-gplus-sharePatent US6305775 - Ink-jet printing method and apparatus therefor
