Nozzle-Driven Self-Priming Piezoelectric Inkjet Based on Capillary Action for Variable Angle Printing

Inkjet printing is an efficient noncontact on-demand printing technology. However, traditional piezoelectric inkjet printing uses pressure waves generated by cavity deformation to jet droplets, air entering the cavity will lead to the failure of inkjet printing. Conventional gravity or pressure ink supply method also has problems such as difficulty in ink supply or difficulty in controlling pressure. These are very unfriendly to variable angle printing, especially at elevation angles. Aiming at the above problems, in this work, we propose a nozzle-driven inkjet with the ability of variable angle printing based on piezoelectric microjet technology and capillary constant pressure ink supply. It does not depend on the deformation of the cavity to jet droplets, so it can avoid the problem of performance reduction due to the bubble entering the cavity and enhance the fluid-solid coupling strength of jetting. We carry out the multiphysics coupling analysis to reveal the ejection mechanism of the proposed microjet head. The method to control the ejecting performance is proposed. Experiments results show that the proposed microjet printing can achieve variable angle printing of 360° in the horizontal direction and ±30° in the vertical direction, and the minimum spreading diameter is 293.6 μm when the nozzle diameter is 300 μm.