Investigation on the Droplet Ejection of a Piezo-Printhead

• Main Authors: Liu, Hsin-Yi, 劉欣怡
• Other Authors: Chen Ping-Hei
• Format: Others
• Language: zh-TW
• Published: 1997
• Online Access: http://ndltd.ncl.edu.tw/handle/43154963775372086250

碩士 === 國立臺灣大學 === 機械工程學系 === 85 === The present study aims to investigate the pressure rise in the ink flow channel and the ink droplet formation process of a piezoelectric printhead after an electrical pulse is applied to the printhead. The ink flow channel is simplified as a straight circular pipe followed by a convergent nozzle. Both numerical analysis and experimental observations are performed in this study. In the numerical analysis, a characteristic method is used to solve the one-dimensional wave equation with nonuniform cross-section area for obtaining the transient pressure and velocity variations in the flow channel of the printhead. In addition, an inexpensive flow visualization system was set up to observe the ink droplet injection process. After the piezoelectric material is driven by the input electric pulse, the ink droplet images can be immediately captured by a charge- couple device (CCD) camera and stored in a computer through a frame grabber. The results obtained from the experimental observations are also compared with the numerical prediction. The effects of electric pulse shape and voltage for driving the piezoelectric material on the ink injection length and the ejected droplet weight are also presented.