A New Nozzle for Continuous Inkjet Printers

The shape of a nozzle for high-quality printing was optimized by using a standard, robust design method, and a method for fabricating the optimized nozzle was established. Several fabrication methods were tested, and the best fabrication method, which consists of three drilling steps and a punching step, was selected in terms of productivity, cost, and manufacturing accuracy. As for the shape-optimization process, eight parameters defining the shape of the nozzle were selected, and their influence on the stability of the driving voltage of the ink was evaluated. It was found that the length of the straight-line part in the exit part of the nozzle (defined as the “straight length” of the nozzle) is the most influential of the parameters. After this evaluation, to find the optimum fabrication condition a nozzle was fabricated by drilling and punching under various conditions. Under the optimum condition, it is possible to fabricate a nozzle with accuracy in diameter of 1 µm or less. According to the results of accelerated wear-out tests, it is forecast that the new nozzle can be used for more than 50,000 hours and meet its target usage lifetime.