Computational Fluid Dynamics of Dispersed Mist Phenomenon in a Thermal Ink Jet Printer

摘要

The dispersed mist phenomenon occurs when small ink droplets are blown up and contaminate the inside of the printer. In this paper, we numerically predict the motion of ink droplets in a confined space through Computational Fluid Dynamics to better understand this phenomenon. Our numerical calculations correlate well with our experimental results. A vortex is generated by the interaction of ink droplets and the flow field through momentum exchange. Consequently, ink droplet behavior can primarily be defined by the velocity relative to the surrounding flow field. Experiments reveal that the optical density of the dispersed mist has a minimum peak for jetting frequency. We investigate the effects of jetting frequency on misting and find that air current generated by main drops tends to transport small mist particles to the paper at higher frequencies. This explains why misting is high at low frequencies. It is shown that the nonlinear coupling between the flow field and ink droplets defines the property of the dispersed mist phenomenon in detail.