| 摘要 |
PURPOSE:To obtain stable operation by preventing air from mixing, by a method wherein the nozzle part is magnetized and sealed with magnetic ink in non-flight of ink. CONSTITUTION:When electric power is applied to electromagnets 18a and 18b, nozzles 19a and 19b are magnetized and magnetic ink 22 is strongly attracted to the edge part having high density of magnetic magnetic force 26. When driving signal 21 is applied to piezo-diaphragm 13 under the state where nozzle 19 is not magnetized, because keeping force is not operated at the opening part of nozzle 19, magnetic ink 23 is discharged from meniscus 20. When the driving signal 21 applied to piezo-diaphragm 13 is turned off and magnetic ink drop 24 is separated from nozzle 19, the nozzle 19 is magnetized with electromagnet 18. Then, the opening part of nozzle 19 is again operated with the force keeping magnetic ink 23 and air is not mixed even though rapid pressure decrease of inner ink chamber 15 is generated. Therefore, the driving signal of piezo-diaphragm 13 can steadily operate even though the falling time of voltage is very rapid. |
