Provided is an ink storage module for a printer cartridge having a number of ink storage modules. Each module operatively stores a different colored ink for delivery to a printhead of the printer. The module includes upper and lower plate members having an ink bag located between the plate members to define an ink volume, said plate members displaceable towards and away from each other. The module also includes a bag constrictor assembly engaged with said plate members and configured to act on the bag when the plate members are displaced towards each other to reduce the ink volume, as well as a valve insert having an inlet valve to facilitate refilling of the bag with ink and an outlet valve to facilitate ink delivery to the printhead. The module further has a filter cover positioned between the valve insert and the ink bag to filter contaminants and air bubbles passing between the ink bag and said valve insert.