Patent ID: 7889223

Claim:
A method of aligning printing of a bi-directionally scanning electrophotographic device, comprising: scanning scan lines of a latent image in a first scan direction and a second scan direction opposite the first scan direction on a photoconductive member of the electrophotographic device, wherein the step of scanning further comprises: forming a first diagnostic pattern having no intentional pel mismatch and forming a second diagnostic pattern having intentional pel mismatch; repeatedly tiling the first diagnostic pattern and the second diagnostic pattern to define a first portion of the latent image, the repeated tiling thereby creating a latent calibration page having a plurality of latent bars on the photoconductive member of the electrophotographic device; printing a calibration page from the latent calibration page; observing bars in the calibration page, and based on the observation determining at least one of line length mismatch between scan lines in the first scan direction and scan lines in the second scan direction in which a scan line in the first scan direction has a different length than a scan line in the second scan direction, and differential pel nonlinearity between the first and second scan directions in which spacing between locations of one or more pels in the first scan direction is different than spacing between locations of the one or more pels in the second scan direction; and implementing a correction for altering future scan lines in the first and second scan directions based upon the determining.