The Fabrication of Monolithic Micro Droplet Ejector using MEMS

This paper presents the fabrication of a micro droplet ejector for the application of digital printing system. The ejector makes the ink droplets of approximately 80 squaremum diameter on demand. The ejecting system is the type of face-shooter. The method of actuating membrane is bending mode using d31 of PZT. The size of ejector is 27.6 mm x 27.75 mm x 1.1 mm, and the pitch between nozzles is 2.54 mm, 10 npi. The nozzle and restrictor are very important part for the performance of the ejector such as droplet size and velocity. Therefore, the roundness and straightness of nozzle and depth profile of the restrictor have an influence on the characteristic of droplet. Those are made by deep silicon etching technique for the accuracy and uniformity. The ejector is successfully operated and the measured ejection speed, size of droplet and the ejection frequency are 1 m/s, 80 mum and 1 kHz, respectively.