INK RESIDUAL AMOUNT DETECTOR

PROBLEM TO BE SOLVED: To provide an ink residual amount detector which reduces an actually-remaining ink in the state of having detected that the ink residual amount reached a predetermined lower limit. SOLUTION: The ink residual amount detector is equipped with an ink cartridge 20 having a concave member 41 in which a hollow part 41a is formed at the bottom 40 of an ink tank 23, a float member 30 which is held in the ink tank 23 and has a float part 31 surfacing on the ink level and a magnet part 32 which projects downward from the float part 31 while being able to be fitted to the hollow part 41a of the concave member 41 in one piece, a magnetic sensor 51 for detecting the magnetism of the magnet part 32, and an electronic control unit 52 for making the information showing the emptiness of the ink residual amount of the ink tank 23 indicated on a display part 12 according to the output change of the magnetic sensor 51 for the cases before and after the magnet part 32 is fitted to the hollow part 41a. COPYRIGHT: (C)2008,JPO&INPIT