ANALYSIS OF ELECTROSTATIC EJECTION OF LIQUID DROPLETS FOR PRINTING DEVICES

摘要

An electrostatic inkjet head can be used for manufacturing processes of large display systems and printed circuit boards (PCB) as well as inkjet printers because an electrostatic field provides an external force which can be manipulated to control sizes of droplets. The existing printing methods such as thermal bubble and piezo inkjet heads have shown difficulties to control the ejection of the droplets for printing applications. Thus, the new inkjet head has been proposed using the electrostatic force. A numerical analysis has been performed to calculate the intensity of the electrostatic field using the Maxwell's equation. Also, experiments have been carried out by high-speed camera to investigate the droplet movement using a downward capillary with outside diameter of 500μm. Gravity, surface tension, and electrostatic force have been analyzed with high voltages for a drop-on-demand ejection. Metal particle suspended inks have been patterned for a type of dots on PET and glass substrates.