| 摘要 |
<p>In the ink jet printer, a pressure generation chamber 11 is expanded in a stepped manner, which enables a high speed discharge of a very small ink droplet. Prior to the ink discharge, the pressure generation chamber is contracted so as to enable a high-accuracy gradation printing with a wide range of ink droplet size. A control unit 20 generates: a first contraction signal for contracting the pressure generation chamber 11 without discharging any ink droplet 17; a first expansion signal for expanding the pressure generation chamber 11 to discharge the ink droplet 17; and a second expansion signal to further expand the pressure generation chamber 11 so as to break off an ink column discharged from a nozzle 12 and pull an unnecessary portion of the ink back into the nozzle 12. <IMAGE></p> |
