A printer cartridge for an inkjet printer includes a body configured for user insertion in, and removal from, a cradle of the inkjet printer; a pagewidth printhead incorporated with the body, the pagewidth printhead having an array of nozzles for ejecting printing fluids onto a media substrate; a flexible membrane attached within the body and defining a plurality of pockets each serving as a printing fluid reservoir, each pocket of the flexible membrane being adapted to expand and contract with a volume of printing fluid stored therein; a cover molding for covering the body and sealing the flexible membrane within the body; and a refill port provided on the cover molding and having a plurality of inlets each respectively in fluid communication with one of the pockets, the refill port being configured to removably receive therein a refill cartridge.