Current characteristics of various ejection modes in electrohydrodynamic printing

The real-time observation of electrohydrodynamic printing (EHDP) process is of importance in practical applications. The electric current is a reflection of charge transfer and might provide a potential method to detect the liquid behavior. In this paper, current during EHDP process is measured and studied to investigate the relationship with liquid behaviors. Experimental results show that the liquid ejection can be accurately reflected by the current signal. Current of various ejection modes in EHDP are then examined, and various characteristic numbers are summarized to identify the present liquid ejection mode. This work proposes a simple and efficient method by combining current detection and visual observation to achieve better real-time monitoring and controlling of EHDP process.