Research on Driving Waveform and Residual Oscillation in Piezo Inkjet

Abstract Piezoelectric driving system is an important part in inkjet printing equipment. The driving waveform, the structure of print head, and etc., directly affect the ejection characteristics and the printing accuracy of droplets. In this paper, the driving waveform was taken as the research object, then established a finite element analysis model for driving droplet ejection, the influence of each time component (voltage rise time trise, voltage falling time tfall and voltage dwell time tdwell ) of trapezoidal wave on the displacement of the driver and the pressure at the nozzle orifice was studied and optimized. According to the two-phase flow model of the nozzle developed, the relationship between driving parameters (voltage amplitude, voltage dwell time tdwell, and operating frequency) and jetting characteristics (droplet velocity and volume) was obtained. Finally, a bipolar driving waveform was designed to suppress the residual oscillation. The results show that the damping waveform can effectively suppress the residual vibration of the pressure wave and greatly improve the working frequency and printing accuracy of the inkjet printing head.