Abstract: A pictorial ink jet printer is disclosed. The printer uses a linear array of nozzles each of which records a segment of a row of pixels in a given raster pattern. The pixel segment is recorded by electrostatically deflecting the ink drops from a nozzle to the pixels contained within the segment. The drops from adjacent nozzles are "stitched" or aligned to these ideal pixel positions by aligning the ink drop streams to drop position sensors. Two sensors are used for each nozzle. Preferably, adjacent nozzles share sensors. The sensors are spaced relative to each other to very close tolerances. Consequently, alignment of each nozzle to its two drop position sensors means that the drops from adjacent nozzles are aligned or "stitched.

Abstract: A system for screening image data provided in digital format. The image data is first electronically examined to determine whether or not the data is comprised of highlight, shadow, or midtone. Where the image data is determined to be midtone, the data is processed using a high frequency electronic screen. Where the image data is determined to be highlight or shadow, the data is processed using a low frequency electronic screen.

Abstract: A system for processing halftone image data in digital format. The image data is electronically screened to provide a binary output suitable for storage or printing, the image data being processed in discrete blocks or cells. The error between actual and printed average gray values of each image cell processed is determined and the electronic screen thresholds are modified in accordance with such error (if any) prior to processing the next image cell. At the beginning of the aforesaid process and at the beginning of processing each line, the error is set at zero.

Abstract: A system for processing halftone image data in digital format. The image data is electronically screened to provide a binary output suitable for storage or printing, the image data being processed in discrete blocks or cells. The error between actual and printed average gray values of each image cell processed is determined and the electronic screen thresholds are modified in accordance with such error (if any) prior to processing the next image cell. At the beginning of the aforesaid process and at the beginning of the processing each line, an error is randomly chosen.