Inkjet jet failures detection and droplets speed monitoring using piezo self-sensing

The jetting reliability of the inkjet printhead is a key factor for successful usage of the printer. It is known that the monitoring method using self-sensing signal can detect jetting failures to ensure jetting reliability. However, a monitoring technique using self-sensing signal to identify different failure types with the ability to calculate the droplet speed has not been reported so far. In order to identify failure type accurately, different self-sensing signal features are investigated in the present study, including the improper driving voltage, fluid viscosity and the backpressure control. Furthermore, the self-sensing signal is applied to extract the characteristic parameters and explore the droplet speed monitoring pattern. In order to evaluate the effectiveness of the proposed detection method, a monitoring system consisting of the self-sensing signal acquisition module and the monitoring software interface is also developed in the present study. Experimental results indicate that the monitoring system recognizes jetting failures accurately. It is found that during the normal operation of the printhead, the average error for the single nozzle and the multi-nozzle is 5.03 % and 7.37 %, respectively. (C) 2020 Elsevier B.V. All rights reserved.