Abstract: Data describing an image to be printed on a print medium is transferred to an ink jet print head. The print head has n number of nozzles in a vertical array for sequentially ejecting vertical columns of ink droplets onto the print medium as the print head scans horizontally across the print medium. The vertical columns of ink droplets ejected during a single pass of the print head collectively comprise a swath of the image. As the data is received from a data source, a required memory space is determined which would accommodate a portion of the data describing a swath of the image to be printed using all n of the nozzles. A current available capacity of a memory device is determined and the amount of image data received from the host is determined. A portion of the data that describes a swath of the image to be printed using a number m of the nozzles is transferred to the memory device.

Abstract: A system identifies faulty ink jet nozzles among a plurality of ink jet nozzles in an ink jet print head based on evaluation of a test pattern printed by the print head. The printed test pattern consists of test images, where each of the test images is printed by a corresponding one of the plurality of ink jet nozzles. The test images occupy locations within the test pattern indicated by location coordinates. The test pattern is visually inspected to identify empty locations within the test pattern, where an empty location is a location in the test pattern not occupied by a test image. The empty locations are designated according to the location coordinates of the empty locations. The location coordinates of the empty locations are then correlated to ink jet nozzles that, if functioning properly, would have printed test images at the empty locations. The ink jet nozzles that, if functioning properly, would have printed test images at the empty locations are designated as faulty.