| 摘要 |
PURPOSE:To detect whether the injection of ink drops is done or not at a high accuracy by building a charged electrode and a detection electrode provided at the position in noway blocking the flying of ink drops on the surface of the same insulation substrate to check an induced current generated with the flying of charged in drops. CONSTITUTION:A voltage of several tens - several hundreds V is applied between a charged electrode 14 of an electrode plate 18 in which a detection electrode 15 is connected to a detection circuit 16 and additionally, the charged electrode 14 and the electrode 15 are built on the surface of the same insulation substrate 17 in a space so arranged as not to block the flying of ink drops 13 positioned opposite to the nozzle 11 and the nozzle 11 to have ink drops injected from the nozzle 11 flying as charged in ink drops 13 and as they approach the electrode 15, an electric charge is induced in the electrode 15 opposite in the polarity to the charge of the drops 13. The moment the charge passes a plate 18, the maximum current flows and is amplified to a positive voltage about 100 times higher by an amplifier of the circuit 16 to be compared with the reference voltage by a comparator in the circuit 16. When it exceeds the reference voltage, the detection circuit 16 outputs the detection signal whereby possible injection of ink drops, namely, nozzle clogging can be detected. |
