| 摘要 |
PROBLEM TO BE SOLVED: To prevent the deterioration of various characteristics of a laminate type piezoelectric element by simple circuit constitution by applying drive pulses to the laminate type piezoelectric element to subject the laminate type piezoelectric element to repolarization processing by a re-polarization processing means. SOLUTION: When re-polarization processing is designated to a CPU 45 also used as a re-polarization processing means and a heating control means, a timing signal is generated from a timing signal generation circuit 43. At the same time, required power supply voltage is applied to a head driving circuit 42 from a power supply control circuit 44 to apply required drive pulses to the respective laminate type piezoelectric elements of an ink jet head 41. By performing re-polarization processing as mentioned above, the lowering of displacement quantity by the deterioration of the laminate type piezoelectric elements with the elapse of time can be restored and a change of a dot diameter or the irregularity of a dot position is reduced. |
