Ink is flowed through an ink flow channel of an inkjet print head, in a volume far greater than the volume required for printing purposes. The excess ink cools the print head and also aids in purging bubbles from the head. Ink for printing is extracted from the flow channel by capillary channels and conveyed to the ejection mechanism of the print head. In operation, ink from a stationary reservoir is circulated by a low-pressure pump through a particle filter and gas separator, and to the print head by a low-pressure trailing tube system, with the excess ink returned to the reservoir. The pressure of the ink at the capillary is maintained below atmospheric pressure, preferably utilizing hydraulic pressure created by locating the vented ink reservoir at a level below the print head. Leakage of ink from the print head is thereby prevented, and a positive ejection force is required.