Overview of thermal ink jet technology

Abstract

In the recent years, thermal ink jet (bubble jet) has emerged to become a fast growing printing technology with market applications first aimed at the low end, high quality and color workstation printers. The break-through in this ink jet technology came in the areas of low cost/high volume manufacture using semiconductor thin-film processing, improved apparent reliability and the ability of high quality printing on wide range of office papers. Although the print head technology appears simple and compact, the underlining thin-film structures, micro fluid channels and drop generation process are by no mean straight-forward. In fact, the ink chemistry, the material integrity and the device physics are closely coupled to provide the proper functionality of the print engine. Hence optimization of the technology can only be achieved through complete device integration. In this paper, the basic implementations of the thermal ink jet technology is presented. The physics of bubble/drop formation process is described using results obtained from our experimental studies. Different failure modes of the electro-thermal drop generator (in particular, the thin-film resistive heater) are discussed. Results can be extrapolated to obtain a basic understanding in the requirements of the ink media and the material structure. Based on the current knowledge of this printing method, projections of the technology limitations in practical implementations can be made to support a view that thermal ink jet will become the dominant low end printing technology in the near future. © 1989 SPIE.