| 摘要 |
PURPOSE:To enable easy removal of bubbles without maintenance tools or separation of an ink jet head from a device by applying an operational signal which causes a sequential regular change of frequency to the ink jet head and eliminating bubbles through their discharge with ink. CONSTITUTION:The basic waveform of an input signal to be applied to an ink jet head is a sine wave with a wavelength of 50mus. In other words, it is a waveform starting with a phase pi and ending with (-)pi. Oscillations with frequencies of 20, 10, 6.67, 5, 4, 3.33 and 2.86kHz are applied to ink in a pressure chamber by sequentially supplying a signal which pauses by an amount equal to N wavelength (N is an integer of 0, 1, 2...6, 7) after an operation equal to an amount of a single wavelength, at an interval of 6ms. When a signal close to a resonance frequency is input, the ink and bubbles in the pressure chamber oscillate violently, and the bubbles are split and suspended in the ink with some of them being discharged. In this way, the resonance frequency changes each time the bubbles are discharged, and the bubbles are gradually eliminated. Thus the ink is completely restored to its original condition. |
