Electronic auto-correction of misaligned segmented printbars

摘要

A method and apparatus for automatically adjusting the quality of printing made by a scanning type printhead or printbar upon a recording medium advanced perpendicularly to the scanning direction. The scanning printbar includes sequentially printed segments in which the dots or pixels in a segment are printed simultaneously. A source of illumination is passed across a test pattern having features indicative of printhead alignment and discernible under the illumination. The source of illumination is connected to circuitry with determines the variation in light intensity of the test pattern. A value indicative of the misalignment is calculated and used to correct the timing of firing signals between the sequentially fired banks of nozzles of a printbar.