Abstract: An adjustment assembly adjustably mounts opposite ends of elongated guide members on opposite side panels of a printhead carrier support frame of a printer to establish a desired mounting relationship between the guide members and opposite side panels and thereby establish a desired print gap between a sheet of print media passing through a print zone and a printhead supported on a carrier reciprocally moving on the guide members. In addition to the opposite side panels, the adjustment assembly includes a pair of adjustment plates each for placement in a facing relationship with an outside surface of one of the opposite side panels and a plurality of mounting elements associated with the adjustment plates and opposite side panels that enable aligning and mounting them at the opposite ends of the guide members in the desired mounting relationship that establishes the desired print gap.