调控管道声波以主动抑制高精度喷墨打印中的次级液滴

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

按需喷墨打印技术主要依赖于通道内的声波来实现液滴的喷射,其在气体环境中的各前沿领域发挥了不可取代的作用.喷墨打印液滴直径通常在20–100微米范围内,难以进一步减小.对于管道声波触发的受约束界面的振动而开发的新兴的液中高精度打印技术,其可以产生小于喷嘴直径数十倍的液滴,并可以灵活地调整液滴尺寸.然而,当激励很强的时候,受约束界面的残余振动会产生次级液滴,进而影响打印的均一性.在此,本文提出了通过调控管道声波进而调控界面行为的策略,在实现显著主振动的同时有效抑制残余振动.基于实验现象构建了数学模型以描述界面行为是如何调控的,回波时间对界面振动的影响,残余振动影响后续主振动和主液滴的机制都得到了较好的解释.本文的工作为通过调控管道内的声波来调控液滴尺寸和改善打印精度提供了理论指导,并证实了其实际应用的潜力.

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 20–100µm 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.