| 摘要 |
PURPOSE:To prevent further temperature rise at the printing head and pressurize ink to remove dust or the like thereat and restore the head to the initial state automatically by a method wherein a temperature detecting element is provided on the ink jet head to shut off the oscillation of the head upon temperature rise due to the blocking of the head. CONSTITUTION:Ink in an ink reservoir 12 is fed by pressure to the printing head 1 and is injected by oscillating a piezo oscillator 2 with an oscillating section 16. The droplet of ink is charged electrically by a charging electrode 5 and is deflected by deflecting electrodes 7a, 7b to print on printing paper 10. On the other hand, a heat sensitive element 3 detects the temperature of the oscillator 2 and the signal thereof is compared with a standard voltage at a comparating section 14. If it is higher than a standard value, the signal is sent into a command controlling section 19 to output respective control signals for a relay 18 and a motor 21. By these signals, the oscillation is shut off to reduce the temperature of the oscillator 2 and the oscillation is started again when the temperature is arrived within a safety temperature range. On the other hand, the number of revolutions of the motor 21 is increased through a motor control section 20 and the pressure of the ink is increased to remove dust or the like which is blocking the head 1. |
