Primers for print heads

A method for delivering at least two distinct pressurised air flows in a primer apparatus for a print head structure of an inkjet printer, the method comprising:

• generating an air flow using a pump;
• providing a control valve in fluid communication with and disposed between the pump and an outlet valve of the primer apparatus, the outlet valve comprising a venting structure to reduce the pressure of a flow of air supplied to the print head structure by the pump;
• when the control valve is closed, supplying a first pressure to the print head structure that purges the print head structure;
• and
• when the control valve is open, supplying a second, lower pressure to the print head structure that circulates fluid through the print head structure.

A print head structure for an inkjet printer, the print head structure including a primer apparatus comprising:

• a pump to supply a flow of air to the print head structure;
• an outlet valve;
• and
• a control valve that is switchable between a closed state and an open state, the control valve in fluid communication with and disposed between the pump and the outlet valve, the outlet valve comprising a venting structure to reduce the pressure of a flow of air supplied to the print head structure when the control valve is open;
• the primer apparatus having a priming mode, in which a first pressure is supplied to the print head structure by the pump with the control valve in the closed state, and a fluid circulation mode, in which a second lower pressure is supplied to the print head structure by the pump with the control valve in the open state.