| 摘要 |
PURPOSE:To achieve a charge phase control at a high accuracy with a simple construction by a method wherein a part of a nozzle contacting an ink column is grounded through a detection resistance and the breaking time of the ink column is detected according to changes in the current flowing through the detection resistance to control the charge phase. CONSTITUTION:An ink column injected from a nozzle 3 is given a vibration synchronizing the frequency of an excitation signal S1 and broken into ink drops. In such a condition, when a charge voltage E of a fixed voltage +V is applied to a charge electrode 5 beforehand, a current (i) flows through a detection resistance 9 each time the ink column is broken into ink drops to balance the charge of the ink column and a drop formation detecting signal (v) is applied to a generation circuit 10, which shapes the drop formation detecting signal (v) so that the phase control signal is generated to be positioned almost in the center between the rising and the falling of a time pulse signal S2 and sent to a phase control circuit 12. This enables the setting of the optimum phase relationship in the charge without providing a means of detecting charged ink drops. |
