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, resulting in approximately a 4:1 range in printed spot area. The modulation is continuous (i.e., not discrete) over a significant part of the total range, and it 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 photorealistic images.
David B. Wallace, Virang Shah, Donald J. Hayes, Michael E. Grove, "Photorealistic Ink-Jet Printing Through Dynamic Spot Size Control" in Journal of Imaging Science and Technology, 1996, pp 390 - 395, https://doi.org/10.2352/J.ImagingSci.Technol.1996.40.5.art00005