An ink composition is prepared in such a manner that a difference between a dynamic surface tension (mN/m) measured by a maximum bubble pressure method at a temperature of 24 to 26.degree. C. and a static surface tension (mN/m) is within a range from 0 to 7 (mN/m). The ink composition is stored in an ink tank of an ink head, and is supplied from the ink tank to an ink chamber having a discharge port, and a voltage is applied to partitions formed by a piezoelectric material to apply a pressure by the partitions to the ink composition stored in the ink chamber, whereby a liquid droplet of the ink composition is discharged from the discharge port and the liquid droplet is deposited on a recording material to record an image.