Effects of Meniscus Motion on Ejection Performance in Thermal Inkjet Print Heads by 3-D Numerical Simulation and 1-D Lumped Modeling

Undesired meniscus motion at the nozzle exti can cause detrimental effects on ejection performance of an inkjet print head, resulting in degradation of printing quality at high frequency operation. In this study, visulization of droplet ejection and meniscus motion was performed experimentally, and the results were compared with those of numerical simulations. Effects of design factors on themeniscus motion, such as material properties of ink and geometric dimensions of head structure, were investigated by three-dimensional (3-D) numerical simulations. The result demonstrated that the ejection performance and the following menicus motion might be affected significantly due to changes in the design factors. For simple and fast computation, one-dimensional (1-D) lumped model was constructed, and its results were meaningful for the intuitive understanding of ejection performance and meniscus oscillation. Also, effects of different meniscus conditions on the subsequent ejection were investigated by 3-D numerical computations. The results showed that a stabilizing time, e.g., 70μs, was needed for uniform reproducible ejection. The results of this study will be helpful for development of the inkjet print heads of higher performance.