| 摘要 |
PROBLEM TO BE SOLVED: To improve a print quality by providing a first and a second voltage application means with different dot size control methods for applying a pulse voltage of a specified form to a piezoelectric element when applying, for printing a dot of a desired size selected from among dots of varying size. SOLUTION: A voltage value is controlled in a small diameter area as shown by (A) to change a dot gradation. On the other hand, in a large diameter area as shown by (B), a pulse frequency control is performed to change a dot diameter. The voltage value control means controlling the volume of a discharged ink while time in which a pulse voltage is applied is the same. On the other hand, the pulse frequency control to be performed in the large diameter area is such that a pulse is output 5 times at an interval of 10μsec, between the fall and the rise of the pulse in the gradation 10, twice in the gradation 7, three times in the gradation 8 and 4 times in the gradation 9. To print a dot of a large size, a high voltage need not be applied to a piezoelectric element. |
