Photo-Realistic Ink Jet Printing Through Dynamic Spot Size Control

A method has been developed for dynamically modulating the drop volume created by an array piezoelectric drop-on-demand ink jet printhead. A 4:1 range of volume modulation has been achieved to date, resulting in an approximately 4:1 range in printed spot area. The modulation is continuous (i.e., not discrete) over a significant part of the total range, and is achieved with a minimal decrease in throughput. Optical densities for modulated spots have been measured at 300 and 600 dpi for several printhead configurations. Algorithms have been designed to use a combination of continuous modulation and halftoning (using modulated drops) to produce photo-realistic images.