US Patent 6994417 Liquid discharge detection method and apparatus and ink-jet printer apparatus

In a liquid discharge detection method and apparatus which detect a liquid discharged from a liquid discharge head, an electrode is placed at a position where the liquid discharged from the liquid discharge head comes into contact with the electrode while being in contact with the head. When a liquid is discharged, and the head is connected to the electrode through the liquid, the circuit becomes a closed circuit. A voltage generated between the two ends of a resistor is obtained from a current flowing in the closed circuit. When this voltage becomes equal to or higher than a predetermined voltage, liquid discharge can be detected.