Method of compensating for malperforming nozzles in an inkjet printer

A method of compensating for malperforming nozzles in an inkjet printing device having a nozzle performance detector and a printhead with a plurality of nozzles, including a first nozzle which prints along a first path, and at least a second nozzle which is capable of printing along substantially the same path as said first path, said nozzles adapted to printing image pixels containing two or more states according to a swath data signal, wherein each state corresponds to a volume of ink that is desired to be emitted by a nozzle, comprising the steps of:

• a) assigning a state importance value to each state, said state importance value indicating the relative importance of printing the given state compared to printing other states;
• b) computing nozzle performance data for each nozzle responsive to a signal from the nozzle performance detector;
• c) assigning a nozzle malperformance value to each nozzle, said nozzle malperformance value responsive to the nozzle performance data, said nozzle malperformance value indicating the relative image quality penalty of using the given nozzle compared to using other nozzles;
• d) computing a modified swath data signal responsive to the swath data signal, the state importance value, and the nozzle malperformance value;
• and,
• e) printing the image pixels according to the modified swath data signal.