Fludically controlled inkjet printhead

An inkjet printer comprising:

• an ink manifold having an ink inlet and an ink outlet;
• one or more printhead ICs attached to the ink manifold such that ink is distributed from the ink manifold to said printhead ICs, said printhead ICs arranged to extend across the width of a printhead assembly for pagewidth printing and having an array of ink ejection nozzles;
• an upstream ink line connected to the ink inlet;
• an accumulator for holding a volume of ink such that the volume of ink is ejected when the accumulator is activated to cause a positive pressure pulse, the accumulator being positioned in the upstream ink line such that the positive pressure pulse primes the printhead ICs with ink from the ink manifold;
• a downstream ink line connected to the ink outlet;
• and,
• a downstream pump in the downstream ink line for fluid communication with the ink outlet;
• a gas inlet that can be:
• opened to establish fluid communication between the ink manifold and a supply of gas so as to de-prime the ink manifold by forcing residual ink from the ink manifold through the nozzles;
• and
• closed to form a gas tight seal for priming the ink manifold;
• -wherein,
• the downstream pump is independently operable.