Method and apparatus for aligning multiple image print bars in a single pass system.

摘要

An image bar recording system which utilizes a plurality of LED image bars to provide a plurality of latent images which may subsequently be developed in different colors. The print bars are initially aligned so that each color image is precisely registered at the same relative position along the exposed area of a photoreceptor belt (46). The alignment is accomplished by adding non-image fiduciary pixels (51,55) to the ends of each print bar and by forming a pair of opposed alignment apertures (40,42) in the surface of the belt. Y-axis alignment of the print bars is accomplished by detecting edge locations of a first pixel (P1) and using this location to select a centrally located fiduciary pixel (PF). The X-axis alignment is then obtained by rotating the print bar to bring a second selected image pixel into alignment as sensed through a second aperture. Once the initial X and Y-axis alignments are complete, subsequent alignment is maintained through subsequent passes by checking the positions of the previously identified pixels as they advance past additional lead edge apertures formed in the process direction along the belt surface.