70 downward to the position shown in fig3 at the same time the air inlet 98 to the other cylinder is pressurized to drive the corresponding piston downward thereby pulling the control rod and seal body up to the position shown in fig4 in this position liquid ink will only flow to the first reservoir 20 once the first high pressure reservoir 20 is charged the control system may then implement a coordinated action as depicted in the flowchart of fig5 on the first pass through series of steps the reservoir u201c x u201d is the first reservoir 20 while the reservoir u201c y u201d is the second reservoir 22 when a call is made for ink to be supplied to the printhead s the first step is depressurize the u201c inactive u201d reservoir which in this first pass is the second reservoir 22 the inlet of the u201c active u201d reservoir u201c x u201d in this case the first reservoir 20 is then closed and the outlet of that reservoir opened substantially concurrently the inlet of reservoir u201c y u201d or in this case the second reservoir 22 is opened and the outlet closed in the next step reservoir u201c x u201d that is now in communication with the printhead s is pressurized and pressurized ink is jetted through the outlet 40 to the printhead s in a suitable manner as the ink is being utilized by the printheads the u201c offline u201d reservoir is being refilled consequently.