Method and system for providing evidence of printing in event of print head failure

摘要

Systems and methods for providing evidence of printing in metering systems even in the event of a print head failure are provided. Along with generating a primary image for an indicium that evidences payment, a secondary image for the indicium, identical to a corresponding portion of the primary image but at a lower density, with physical boundaries that are within the boundaries of the primary image, is also generated. The primary image is printed by a first nozzle array (46a), and the secondary image is printed by a second nozzle array (46b). Because the primary image completely overlaps the secondary image, the secondary image is undetectable if the primary image is properiy printed. The secondary image provides evidence of printing of the indicium that can be used to obtain a refund for the indicium in the event that the primary image was not printed due to failure of the first nozzle array (46a).