| 摘要 |
PURPOSE:To effectively remove bubbles, dust or the like from the interior of a recording head, by discharging an ink by simultaneously driving a means for forcibly discharging the ink from the recording head and the recording head while varying a driving frequency for the head. CONSTITUTION:A recording operation is started by depressing a printing switch in a switch group, and a recovering operation is carried out when another switch in the switch group is depressed. A negative pressure in a pump 31 is exerted on an ink in a liquid passage in an ink jet head through a tube 112, and the ink in the liquid passage is sucked by the pump. Simultaneously with the suction of the ink, a signal is applied to a head driver, whereby the head is driven. Since the ink is vibrated, removal of minute bubbles or the like sticking to the inner wall of the liquid passage in the head and being difficult to remove is facilitated. The bubbles present in the liquid passage of the head can be discharged irrespective of the size of the bubbles by forcibly discharging the ink while performing or repeating an operation of varying, for example continuously, a driving frequency for the head. |
