Numerical Simulation of Hydro-Acoustic Flow of Liquid in Piezo Inkjet Print Head

This paper presents numerical and theoretical studies of acoustic wave interactions in slightly compressible liquids within piezoelectrically driven inkjet print heads. The interconnected flow channels may cause jet cross-talk, resulting in poor printing quality. Thus, it should be reduced by modifying the channel structure with the acoustic wave interactions considered. Compressible gas flow driven by the sudden movement of a top wall in the channel is calculated using Flow3D and is validated with the result obtained by using the narrow gap theory. For the calculation of pressure waves in the ink flow, a limited compressibility model of the Flow3D is used. It is found that reducing the restrictor width can damp out the jet cross-talk by inhibiting the pressure wave propagation. The degree of cross-talk has been quantified using the maximum values of cross-correlations between neighboring channels and a critical channel dimension for acceptable cross-talk has been proposed. This finding is verified by drop visualization experiments using silicon-micromachined piezo inkjet print heads that are fabricated by our group.