Efficient identification of predicted printer defects for anamorphic

Abstract

Every printing system has characteristic defects which detract from high quality printing. Xerographic printing systems show defects such as banding, mottled colors in large fill areas, trail-edge deletion and starvation where toner concentrations drop at certain color edges, misregistration, and so on. Ink jet printing systems can show ink bleeding, streaking in the direction of head movement, and so on. One approach to reducing predictable printer defects is to modify the digital data being sent to the printer to pre-compensate for the defect. One pre-compensation method identifies runs of color which meet the criteria likely to cause a printing defect and applies a function f(edge-distance, object-type) to such runs to modify them appropriately. However, if multiple defects are being corrected, an efficient method is needed to identify potential defects since a normal search procedure performed on a band of collected runs one at a time for each defect is time-consuming. Instead, a method is described by which modules responsible for detecting and correcting each defect register patterns of runs with a search module that are predicted to trigger defects. These registered patterns can then be applied as keys to a lookup table to quickly find if a printer defect pattern has been found, and which correction module to call to pre-compensate for the defect.