Patent ID: 7524016

Claim:
A cartridge unit for an inkjet printer, the cartridge unit comprising: a printhead assembly having an array of ink ejection nozzles; an ink storage compartment sealed from atmosphere, the ink storage compartment having a variable storage volume and a displaceable wall section biased to expand the variable storage volume to generate a sustained negative pressure, whereby an ink pressure at the array of ink ejection nozzles is reduced; an ink feed system for connecting the ink storage compartment to the printhead assembly; and, a printhead maintenance assembly, the printhead maintenance assembly having a capper spring biased against the array of ink ejection nozzles for covering the array of ink ejection nozzles, wherein, the printhead maintenance assembly includes a catch element engaged with an actuator, the catch element being movable by the actuator in a direction to counteract the biasing of the capper against the array of ink ejection nozzles.