| 摘要 |
PURPOSE:To make the acquisition of a constant stable normal concentration for a long time possible, by specifying the pulse of an optimum discharge state according to the critical point of ink discharge from an ink discharge opening. CONSTITUTION:The pressure of ink in the ink discharge opening 6 is established at a value slightly larger than the air pressure near the ink discharge opening 6 and a potential difference is provided between an electrode plate 2 and the ink 7 in the ink discharge opening 6 with a signal source 8. Then, the ink 7 in the ink discharge opening 6 is drawn out with the force of electric field, the meniscus of ink 7 generated at the ink discharge opening 6 being elongated onto the air discharge opening 3 side, pulled off and the drop of ink is discharged from the ink discharge opening 6. Then, the presence of the ink discharge from the ink discharge opening 6 is detected and the pulse of an optimum discharge state is controlled to be specified. Therefore, by detecting the change of the threshold value of ink discharge without direct measurement of the concentration of a substance to be recorded, the printing density of the substance to be recorded can be made constant for a long term. |
