A printer is provided comprising an elongate printhead for printing across the pagewidth of print media, a rotatable, elongate platen arranged to support the print media being printed on by the printhead, a sensor for sensing a thickness of the print media, and a controller arranged to rotate the platen. The platen can support the print media at a plurality of predetermined distances from the printhead with the rotation of the platen providing selection of the plurality of predetermined distances. The controller rotates the platen in response to the sensed print media thickness so as to select a predetermined distance of the plurality of predetermined distances which accommodates the print media.