Abstract: A printer having of a printhead having first and second elongate printhead modules, the printhead modules being parallel to each other and being disposed end to end on either side of a join region, wherein the first printhead module is longer than the second printhead module. At least first and second printer controllers configured to receive print data and process the print data to output dot data for the printhead, wherein the first printer controller outputs dot data to both the first printhead module and the second controller; and the second printer controller outputs dot data to the second printhead module, wherein the dot data output by the second printer controller includes dot data it generates and at least some of the dot data received from the first printer controller.