Characteristics of an electro-rheological fluid valve used in aninkjet printhead

Abstract

The demand for non-impact printers has grown considerably with theadvent of personal computers. For entry-level mass production, twodrop-on-demand techniques have dominated the market - piezoelectric impulseand thermal-bubble types. However, the high cost of the piezoelectricprinthead and the thermal problems encountered by the thermal-bubble jetprinthead have restrained the use of these techniques in an array-typeprinthead. In this study, we propose a new design of printhead with anelectro-rheological (ER) fluid acting as a control medium. The ER fluid valvecontrols the ink ejection. As a first step toward developing this newprinthead, the characteristics of an ER fluid valve which controls thedeflection of the elastic diaphragm are investigated. First, the response of aprototype is tested experimentally to prove the feasibility of using this ERvalve for the inkjet printhead. Then, the discretized governing equation ofthe ER valve is derived. Finally, the prototype of the ER valve is fabricated.The experimental measurement based on the sinusoidal response verifies boththe theoretical analysis and the controllability of the response of the ERvalve by the applied electric field.