Electrostatic droplet ejection using planar needle inkjet head

Droplet ejection technique has been expected to apply in various disciplines such as electronics devices, bio-system devices and so on. The technique has mainly three kind of methods; piezoelectric inkjet, thermal inkjet and electrostatic inkjet. Especially, electrostatics inkjet has great advantages that it can eject fine droplets and its structure is simple compared with other method. Most observation of electrostatic droplet ejection has carried out on capillary-shaped needles[ 13. On the other hand, ejection from cone-shaped needle has not been analyzed in detail because of the difficulty to survey the microscopic area with 3-D configuration needles[2,3]. In the present paper, observation of electrostatic droplet ejection is described using planar needle inkjet. The use of planar needle head can model the 3-D needle and, therefore, the results provides further understanding of the electrostatic droplet ejection.