Dynamics of entrained air bubbles inside a piezodriven inkjet printhead

Abstract

Entrained air bubbles inside a piezoelectric inkjet printhead cause a malfunction in the droplet formation and deteriorate the reliability of inkjet printing. The dynamic motion of the entrained air bubbles is investigated optically by utilizing a high-speed imaging system. Air bubbles, ingested through the inkjet nozzle, are surrounded by a pulsating pressure field inside the inkjet printhead. The bubbles oscillate and move along the inner wall of the printhead as they are subjected to the Bjerknes force. As the bubbles attract each other, they continuously coalesce and grow due to rectified diffusion until they reach the equilibrium condition.