A Novel Method for Evaluating Ink-Jet Print Head Directionality

摘要

Directionality of droplet ejection is an important character for the ink-jet printing process in many of the industrial applications. The conventional strobe system can only be used for roughly estimating the average directionality of a group of consecutive droplets. Other apparatuses available in the market are both costly and time-consuming for multi-nozzle measurement. This study reveals a fast and economic method for measuring the directionality of a multi-nozzle print head based on every single droplet behavior. The apparatus includes an X-Y table for supporting the printed media, a drop on demand print head for ejecting droplets, and a set of optical system for capturing dot images of droplets on printed media. Software programming based on the statistic and optimization theory is also developed for calculating the ejection directionality in this study, which includes two kinds of measurement method. One is the deflection of droplets ejected from every single nozzle. The other is the deviation of the average droplet position from its ideal position. Consequently, this new measurement technique is a powerful tool for developing highly accuracy and quality of inkjet print head.