| 摘要 |
<p>The Niyama number of a flow path for phase change ink is the ratio of cooling rate of the ink to the thermal gradient of the ink along the ink flow path. Print head assemblies can be designed and configured to achieve ink flow paths having Niyama numbers that are greater than a critical Niyama value, These designs reduce entrapment of air in the ink as the ink is changing phase and provide optimal bubble and void mitigation for phase change ink. The thermal gradient of the ink flow path can be achieved using passive and/or active thermal elements disposed along the ink flow path. A print head assembly for an inkjet printer thus comprises:
one or more components (131,220) fluidically coupled to define an ink flow path; and
one or more thermal elements (543-547) disposed along the ink flow path and configured to maintain a ratio of cooling rate to thermal gradient along the ink flow path to be above a critical Niyama value for the ink flow path.</p> |
