| 摘要 |
PURPOSE:To detect an ink near end by providing an ink reservoir which communicates with a print head at the lower end of an ink tank containing a porous material impregnated with a water-soluble ink, arranging an electrode at a part of the porous material and a part of the ink reservoir and detecting a resistance variation between electrodes. CONSTITUTION:An ink reservoir 12 which stores and holds water-soluble ink in a foam 7 is formed in an ink tank 8 filled with a foam consisting of a porous material such as foamed urethane resin internally. An electrode S1 is provided on the inner wall surface of the ink tank 8 in such a manner that the electrode S1 comes in contact with the foam 7. On the other hand, the other electrode S2 extends into a communication hole 13 passing through a rubber stopper 14 so that the electrode S2 comes in contact with water-soluble ink. If ink in the foam 7 decreases and a gas which has entered begins to decrease an area of a part where the ink connects to the ink reservoir 12, an electric resistance increases rapidly, then the increase is detected as a value of variation by a differential circuit 16 and a warnig lamp 18 lights. |
