Coordination of pressure and temperature during ink phase change

A method of operating an ink jet printer, comprising;

• applying pressure to ink in an ink flow path of the ink jet printer;
• and
• coordinating the pressure applied to the ink with temperature of the ink during a time that the ink in the ink flow path is undergoing a phase change;
• and
• forcing air out of the ink through a free surface of the ink flow path in response to coordinating the pressure applied to the ink with the temperature of the ink.

An ink jet printer, comprising:

• a print head assembly comprising:
• a print head with ink jets configured to selectively eject ink toward a print medium according to predetermined pattern;
• an ink flow path, the ink flow path configured to allow passage of a phase-change ink along the ink flow path to the ink jets;
• a pressure unit configured apply pressure to the ink;
• and
• a control unit configured to control the pressure applied to the ink and to coordinate the pressure applied to the ink with temperature of the ink during a time that the ink in the ink flow path is undergoing a phase change, the coordination of the pressure applied to the ink with the temperature of the ink configured to push air out of a free surface of the ink flow path;
• and
• a transport mechanism configured to provide relative movement between the print medium and the print head.

A print head assembly for an ink jet printer, comprising:

• one or more components that define an ink flow path of the ink jet printer, the ink flow path configured to allow passage of a phase-change ink along the ink flow path;
• a pressure unit configured to apply pressure to the ink;
• and
• a control unit configured to coordinate the pressure applied to the ink with temperature of the ink during a time that the ink is transitioning form a liquid phase to a solid phase and a portion of the ink in the ink flow path is in a solid phase and another portion of the ink in the ink flow path is in a liquid phase, wherein coordination of the pressure applied to the ink with the temperature of the ink is configured to push air out of a free surface of the ink flow path.

A method of reducing voids in the ink of an ink jet printer, comprising:

• determining temperature of ink in an ink flow path of the ink jet printer during a time the ink is undergoing a transition from a liquid phase to a solid phase, wherein a portion of the ink in the ink flow path is in liquid phase and another portion of the ink in the ink flow path is in solid phase;
• coordinating pressure applied to the ink with the temperature of the ink during the transition;
• and
• forcing air out of the ink through a free surface of the ink flow path in response to coordinating the pressure applied to the ink with the temperature of the ink.