| 摘要 |
PURPOSE:To enable to detect the accurate ink remainder by an inexpensive cost by turning OFF a voltage applied to a heating resistor at the time of detecting the remainder of the ink. CONSTITUTION:An ink discharging heater 2 is provided in an ink passage having an outlet 1B of an ink reservoir 1, and a switch 4 for turning ON and OFF the supply voltage and a driver 5 for energizing the heater 2 are provided between the heater 2 and a power source 3. Electrodes 6, 7 for detecting the remainder of the ink are provided in the reservoir 1, and connected to the negative and positive input terminals of an operational amplifier 9 through interlocking switches 8, 10. Further, the value of the current flowed to the ink is amplified by the amplifier 9, and outputted from the current/voltage conversion output 11 for detecting the remaining amount. Then, the supply voltage to the heater 2 is paused in the state that the switch 5 and the driver 5 are turned OFF when the remainder of the ink is detected. |
