Investigation of Water Jet Phenomenon and its Application for Imaging Technology

对液滴的静电形成进行了研究。在充满水的绝缘毛细管和金属板电极之间施加高压。在适当的电压和水位条件下，观察到暗放电时水滴的形成。虽然静电吸引库仑力很小，在低于电晕起始电压时只有10 μN左右，但在一定条件下，它足以在表面张力的作用下将水滴分离到毛细管中。水滴的直径约为一毫米。而在电晕放电开始时，由于带电雾的库仑斥力，水雾从管尖呈宽角度分散。观察到在管的尖端形成了一个泰勒锥，在电晕放电开始时，锥的尖端被打破，形成一个非常小的液滴。当外加电压进一步增加时，水雾变得像喷雾一样分散，因为离子风阻止了水滴的分离和扩散。通过施加脉冲电压控制小液滴的形成。液滴的直径取决于施加的电压和管的直径。液滴的体积大约有几百皮升。在纸上进行了初步的喷墨打印，并成功地打印了1,270 dpi的汉字。建立了另一个实验装置来控制液滴的下落位置。在毛细管和平板电极之间设置环形电极来控制液滴的下落位置。然而，由于该系统只有一个喷嘴，打印速度非常慢。因此，我们一直在开发一种多喷嘴系统，该系统由两个平行的填充油墨的管和金属板电极组成。利用有限差分法对电场进行了三维计算，推导出电极间的串扰，并提出了一种通过调整外加电压波形来消除相邻喷嘴间串扰的新系统。我们也一直在开发利用静电喷墨系统的微电子电路的无掩膜印刷技术。通过静电力将含有银纳米颗粒的膏体滴注到衬底上形成电极图案。通过在板电极和含有银浆的细管之间施加脉冲电压来控制液滴的形成。结果表明，在玻璃衬底上成功地打印出了间距为200 μm的线电极。通过在电极上涂覆玻璃浆料，实现了多层印刷。综上所述，这一现象有望用于新型喷墨打印头。少

An investigation was conducted on electrostatic formation of a liquid drop. High voltage was applied between an insulative capillary tube filled with water and a metal plate electrode. Formation of a water drop was observed at the dark discharge under conditions of appropriate voltage application and water level. Although the electrostatic attractive Coulomb force is small, in the order of 10 μN at the voltage lower than the corona onset, it is large enough to separate the water drop to the capillary tube against surface tension at certain conditions. The diameter of the drop was about one millimeter. At the beginning of corona discharge, however, water mist was dispersed at wide angle from the tip of the tube due to the Coulomb repulsive force of charged mist. It was observed that a Taylor cone of water was formed at the tip of a tube and the tip of the cone was broken to form a very small droplet at the beginning of the corona discharge. When the applied voltage was further increased … More , water mist became to be dispersed like spray, because the ionic wind prevented the separation and spread of the droplet.The formation of a small droplet was controlled by the application of pulse voltage. The diameter of the droplet, depended on the applied voltage and the tube diameter. The droplet volume was in the order of several hundred picoliters. Preliminary inkjet printing on a paper was also demonstrated and succeeded in printing 1,270 dpi kanji character. Another experimental set-up was constructed to control the dropping position of the droplet. A ring electrode was settled between the capillary tube and the plate electrode to control the dropping position of the droplet.However the print speed was deadly slow because this system had only single nozzle. Therefore we have been developing a multi-nozzle system that consisted of two parallel tubes filled with ink and the metal plate electrode. Three-dimensional calculation of the electric field was conducted by the Finite Difference Method to deduce the cross-talk between the electrodes and it is proposed that a new system that the waveform of the applied voltage was adjusted to cancel the cross-talk between the adjacent nozzle.We have been also developing a mask-less printing technology for microelectronic circuits utilizing an electrostatic inkjet system. Drops of paste that contained Ag nano-particles were injected on a substrate by the electrostatic force to form electrode patterns. The formation of the drop was controlled by the application of pulse voltage between the plate electrode and a fine tube that contains Ag paste. It was demonstrated that line electrodes of 200 μm pitch were successfully printed on a glass substrate. A multi-layered printing was also realized by over coating glass paste on the electrode.I conclusion, this phenomenon is expected to be utilized for a new inkjet print head. Less