A method of multi-tone printing employs a drop-on-demand printing apparatus 100 for depositing ink droplets from an array of channels 104 on printing element areas of a substrate 111 which is movable relatively to said apparatus. The channels length and nozzle location and dimensions afford each channel...http://www.google.com.au/patents/US5512922?utm_source=gb-gplus-sharePatent US5512922 - Method of multi-tone printing
