A printhead module is provided for an inkjet printhead assembly. The printhead module includes a support. An elongate carrier is mounted to the support. The carrier defines a plurality of transverse ribs and an ink channel located between the ribs. A subassembly includes a micro-electromechanical integrated circuit (IC) configured to eject ink. The subassembly is mounted to the carrier so that the support, carrier and subassembly define a plurality of sealed ink chambers which can feed ink to the IC via the ink channel.