| 摘要 |
PURPOSE:To keep the function of ink end detecting operation even when a polarized film is formed by electrolysis by arranging one electrode to a part of an ink tank and forming the other electrode into a hollow needle to detect the change of the resistance between both electrodes and using the electrode also used as the hollow needle on an earth side. CONSTITUTION:An ink droplet is emitted from the nozzle of a recording head 3 corresponding to a recording command to be recorded on recording paper. An ink tank 7 having foam 6 composed of a porous member received therein is provided above the recording head 3 and a hollow needle 5 is inserted in the ink chamber 12 provided to the lower end of the ink tank 7 to be allowed to communicate with the recording head 3. One electrode S1 is provided to the inner wall surface of the ink tank 7 to apply reference voltage to the electrode S1 and a resistance change quantity detection circuit is connected to the electrode S1 and, when a resistance value exceeds a definite level, an output signal is generated. The hollow needle 5 coming into contact with ink is used as the other electrode S2 to be set on an earth side and the ink tank is replaced before the formation of a polarized film on the electrode is advanced to prevent the detection inferiority of an ink end. |
