A printhead cartridge is inserted in a printer in accordance with a particular protocol. The printer has a cradle with a reference surface for engaging a datum point on the printhead cartridge to support the nozzle face at a precise spacing from a media feed path. The printer also has a latch for securing the printhead cartridge in the cradle. The protocol involves the steps of placing the printhead cartridge in the cradle such that the datum point rests on the reference surface, moving the latch to the closed position to secure the printhead cartridge in cradle, providing a mechanical linkage between the latch and a fluid interface to ink tanks in the printer. The fluid interface sealingly engages the fluid coupling upon moving the latch to the closed position without urging the reference surface to disengage from the datum point.