MATERIALS AND PROCESSING STUDIES FOR THERMAL INK-JET DEVICES.

Abstract

The use of thin film heaters to thermally generate gas bubbles that eject ink through a nozzleplate has been employed to develop Drop-On-Demand printheads by Hewlett-Packard and Canon. Products using this transducing effect require very reliable heaters functioning under highly adverse stress conditions. The thermal barrier serves to retard heat flow to the substrate when the resistor is heated to a few hundred degrees in several microseconds for bubble formation, and permits heat flow during the rest of the duty cycle. The resistor must meet a variety of demands which will be discussed below. The passivation layers must be thermally conducting, electrically insulating and protect against corrosion, bubble cavitation and fatigue effects. The authors report here some ongoing materials investigations of such device structures.