PURPOSE: To correct a change generated in a graining process of a nozzle as a result of a change in a nozzle shape due to electrolytic corrosion, by regulating an exciting voltage of a printing head in accordance with a time spent in a printing.

CONSTITUTION: A graining region of a nozzle varies with the number of printing papers covering over a long period of time. A change is produced at an upper limit A and a lower limit B of an exciting voltage Vp of a piezo-electric vibrator of a printing head for a change control type ink jet recorder in which a dystuff system solution serves as ink and a metal nozzle is used. For example, if the exciting voltage Vp of the piezo-electric vibrator is set to a center of a workable region C, in an initial exciting vibration voltage Vp, the exciting vibration voltage, produced after 70,000 copies of standard originals of an A4 size are printed, attains 42V, and it increases by about 2V each time 10,000 sheets are printed. Thus, if the exciting vibration voltage Vp is regulated by 2V each time 10,000 sheets are printed, this causes insuring of reliability of a printing covering a long period of time.