| 摘要 |
PURPOSE:To detect whether the ink drop is ejected from the ink jet head or not by rotating an impeller or vane wheel with the ink drops which fly and come, and converting this rotary motion into an electric signal of pulse form. CONSTITUTION:When the ejection ink of nozzle head 4 is recorded on recording paper 7 via electric charge electrode 5 and deflecting electrode 6, impeller 1 rotatable by the ink drops, slit plate 2 secured to the impeller 1, and photo-sensor 3 are disposed. Pulse a synchronous with the output pulse of the photo-sensor is given to monomutivibrator MMB, and it is arranged that the pulses a and b are applied to AND gate AND. Therefore the detection of high S/N ratio can be performed by continuing the recording when the signal c appears at AND gate AND in a predetermined time since the voltage of an opposite polarity is applied to the electric charge electrode 5, and by suspending the recording when it does not appear. |
