INK-ON-DEMAND TYPE INK-JET PRINTING.

Ink-on-demand type ink-jet printing is a potential technique for facsimile application because of the ease of ink-handling and the compact size of the printing head, although it has several undefined operating characteristics to be improved before obtaining ultimate performance. This article describes the results of experimental investigations through observation of behavior of ink droplets during ejection in terms of optimizing geometry, vibration characteristics and incorporation of an air-flow scheme to improve the mechanical design and dynamic characteristics of the ink-on-demand printing head. Experimental investigation of recording materials is also described. Considerable improvement has been achieved, especially by the incorporation of the air-flow scheme. This improved design makes it possible to print at high speed (about 10 times faster than a conventional design) and results in high-quality reproduction with the ink-jet facsimile system.