이동소재가 Single-Pass형 디지털섬유인쇄 시스템에서의 액적거동 메커니즘에 미치는 영향

The inkjet printing technology, which was originally developed to apply conventional computer printers, has also received considerable attention in the digital textile printing (DTP) system. The printing quality in single-pass type DTP system is influenced by the substrate movement and distance between nozzle exit and substrate as well as the nozzle shape and ink properties. In the present work, the mechanisms of droplet formation and its ejection of the piezoelectric actuated droplet generator are investigated numerically. To predict the droplet ejection phenomenon in simulating interfacial flow fields involving inertia, capillarity, free-surface movement, and unsteady state, a commercial CFD software of STAR-CCM+ was utilized in numerical calculation. The mechanisms of formation and ejection of main droplet included the satellite one were studied and the effects of the moving substrates (i.e., textiles for printing) and actuator frequency on the printing performance were also investigated numerically. Especially, the Couette flow, which is caused by a moving substrate in the DTP system and influenced the amount of mismatched target, could be found from the point of flow characteristics view.