US Patent 7296867 Printing apparatus having printhead chips with overlapping end portions

A printing apparatus includes an array of at least two printhead chips, an end portion of a first printhead chip overlapping an end portion of a second, consecutive printhead chip. Each printhead chip includes a plurality of ink ejection nozzles. A sensing means is operatively arranged with respect to the printhead chips to generate overlap data representing an extent of overlap of the end portions. The apparatus includes means for generating continuous tone print data for the array of printhead chips and an initial dither matrix to be applied to the continuous tone print data. A summation means applies the overlap data to the initial dither matrix to generate an output value. A processing means applies the output value to the continuous tone print data.