| 摘要 |
PURPOSE:To obtain a charge detecting method having no unstability due to ink contamination by grounding a partly conductive gutter via a resistor and amplifying a voltage presented at the resistor. CONSTITUTION:An ink injected from a head 5a is isolated into ink particles at a position advanced at the prescribed distance. A charging electrode 6 is disposed at the isolated position, and when a charging voltage is applied to the electrode 6 at the isolating time point, the ink particles are charged in the polarity opposite to the charging voltage polarity. A gutter 9 is a conductor, and is secured to a gutter holder 13 of the insulator. One end of the core wire of a shielded wire 15 is connected to the gutter 9, and the other end is connected to a charge detector 20. In the detector 20, the gutter 9 is grounded with a resistor having a resistance much smaller than the resistance between the gutter 9 and the earth of the filter 10, and the voltage across the resistor is detected. |
