at least two printhead modules each comprising at least two, separate printhead integrated circuits, each printhead integrated circuit having nozzles formed therein for delivering printing fluid onto the surface of print media, and a one-piece support member commonly supporting the printhead integrated circuits of the respective printhead module and having at least one longitudinally extending printing fluid channel and associated apertures for distributing printing fluid to the supported printhead integrated circuits; and

a casing in which the at least two printhead modules are arranged so as to be removably mounted in linearly aligned relationship through removable engagement of the support member of each printhead module with a support frame of the casing, the support member of each printhead module having a first tab received in a recess of the support frame and a second tab clamped between the support frame and a mounting element mounted to the support frame so as to allow constrained movement of the printhead modules relative to the casing, the printing fluid channels of the linearly aligned support members of the modules being configured to communicate said printing fluid with one another,

wherein the assembly has an aggregate length and a number of printhead modules predetermined to provide for selected pagewidth printing.