抄録
Applying micro spray of electrostatic inkjet to precision film coating was examined experimentally. Using a single nozzle, high quality coating was demonstrated by the authors elsewhere. A critical issue, however, lies in terms of productivity; the amount of liquid jetted from a nozzle was too small to obtain sufficiently high coating speed. To overcome the situation, a possibility of a multi-nozzle was tried in this report. The liquid was dilute dispersion of photo-sensitive pigment. As results, from seven nozzles of stainless steel multi-nozzle, jetting direction was fanned out toward the opposite plate electrode. By clogging the both end nozzles and making them as electrodes, the direction was remedied and parallel jets were obtained. According to the increment of applied voltage, jetting mode was varied from dripping mode to cone-jet mode. Although the variation of jetting mode was qualitatively the same as that of a single nozzle, the higher voltage was required for a multi-nozzle. Furthermore, the mode change and uniform distribution of droplets always started from the end nozzles. Again, high voltage was required to alleviate the fluctuation of the droplet size distribution. From simple line-coating experiments suggested that the multi-nozzle with dummy electrodes at high applying voltage could jet well-oriented fine and uniform droplets to acquire quality film coating.
