Mechanism of drop constriction in a drop-on-demand inkjet system

In this paper, results of an investigation on the process of drop formation in piezoelectrically driven drop-on-demand inkjet systems are presented. The focus is on theoretical hydrodynamical aspects of the process with special attention to drop constriction. It is shown that the inception of drop constriction has its origin in acceleration forces in contrast to the well-known phenomena in the field of interfacial instability such as pendant drop, end pinching and capillary wave break-up. Some results from computer simulations and from experimental investigations are also added to illustrate relevant processes preceding and following drop constriction.