| 摘要 |
<p>PURPOSE: To expand the operation range corresponding to the environment of a system by providing an ink sump having two parts to an ink jet printing head and setting a fixed vol. part to a strong chamber while setting a variable vol. part to the flexible bag within the wall of the strong chamber. CONSTITUTION: An ink sump 12 is filled with ink at first through an opening part 42 and, thereafter, the opening part 42 is hermetically closed by a plug 44. When printing is performed at first by a pen, the ink ejected from a printing head leaves the partial vacuum or reduced pressure corresponding to the inside of the ink sump 12 and a flexible bag 27 begins to collapse. When the bag 27 collapses, the vol. of the ink sump is reduced and the speed partially establishing a vacuum becomes slow by the continuous ejection of the ink. In spite of the speed reducing action by the bag to the pressure of the ink sump, reduced pressure increases continuously along with the continuous ejection of the ink. This increase is continued until the pressure difference between the ink sump 12 and an aerated overflow sump becomes the difference sufficient to draw air bubbles to the ink sump through an air bubble forming orifice 36.</p> |
