Suppression of secondary droplet for high-definition drop-on-demand inkjet by actively regulating the channel acoustic waves

Drop-on-demand inkjet technology has played an irreplaceable role in various cutting-edge fields in the gaseous environment, which relies on the acoustic waves in the channel to dispense droplet. The droplet diameter is about 20–100 µm and is difficult to be further reduced. For the emerging high-resolution inkjet technology in a liquid environment based on the confined interface vibration triggered by acoustic waves in the printhead, the droplet size can be 10 times smaller than the orifice, which can also be facilely regulated. However, the residual vibrations of the confined interface will dispense secondary droplets when the stimulation is significant, interfering the uniformity of the printing results. Herein, a strategy that can regulate the interface behavior by manipulating the acoustic waves in the channel is proposed, which can achieve a significant main vibration while the residual vibrations are effectively suppressed. A mathematical model is constructed based on the experimental phenomenon to explain how the interface behavior is regulated. The influence of echo time on the interface vibrations, the mechanisms of how the residual vibrations affect the subsequent main vibration and primary droplet are revealed. This work provides a theoretical guidance for regulating droplet size and improving the printing resolution of inkjet in a liquid environment by regulating the acoustic waves in the channel, and demonstrates its practical application potential.