The present study has focused on the characteristics of droplet formation from an inkjet nozzle driven by a piezoelectric actuator. As an operating fluid, ethylene glycol was used and the physical properties of it such as viscosity, surface tension, contact angle and shear stress were measured. During the experiments, various temperatures and driving voltages are imposed on a capillary tube. These conditions result in a proper drive condition or an overdrive condition. In case of the proper drive condition, an image processing technique is applied to measure the diameter of a single free drop. As a result, the size of droplet is increased when the driving voltage is increased from 160 V to 190 V at 25$^{circ}C$ In the overdrive condition where temperature or driving voltage becomes higher than the proper drive condition, satellites and the misdirected jets happen.