PURPOSE: To detect the rest of ink having high specific resistance with high precision by detecting the electric resistance or current value between two conductive foil sheets.
CONSTITUTION: When an ink tank 1 is full of the ink 2, the two conductive foil sheets 4 are dipped in the ink 2 and in an open state. If the ink 2 is oily and has high specific resistance in this state, high electric resistance of a low current value is obtained. As the ink 2 decreases in amount, the two conductive foil sheets 4 come closer to each other by the surface tension of the ink 2 and nearly contact each other below the certain amount of ink, thereby obtaining extremely small electric resistance or an extremely large current value. The variation in the electric resistance of current value is detected by a detecting means to detect the rest of the ink 2. Therefore, the rest of ink which has high specific resistance, specially, like oily ink is detected precisely.
ITO YOSHIMASA
MIURA MASAYOSHI
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