In this study, the authors propose a new design for an external counter electrode for electrohydrodynamic (EHD) printing by considering two important aspects: robustness of EHD jetting and real-time monitoring for jetting reliability. For this purpose, the authors investigated the EHD jetting behavior in both cases: the external counter electrode positioned below and that positioned above the nozzle tip. It is well known that the ring electrode should be symmetric around the nozzle tip to ensure jet straightness. However, they found that a non-symmetric electrode can also produce straight jetting in the case when the external electrode is installed above the nozzle tip. In this way, real-time jetting monitoring based on the external camera view can be implemented by cutting part of the electrode without affecting jetting performance.
Thanh Huy Phung, Kye-Si Kwon∗, Hayeong Park, Zhao Lu, "A Counter Electrode Integrated Electrohydrodynamic Head with Capability of Real-Time Monitoring" in Journal of Imaging Science and Technology, 2018, pp 040403-1 - 040403-9, https://doi.org/10.2352/J.ImagingSci.Technol.2018.62.4.040403