Patent ID: 7277111

Claim:
An electrophotographic device comprising: at least two laser sources, each laser source independently controllable to emit a laser beam; a photoconductive surface operable at two or more image transfer rates; a scanning device having a plurality of deflecting surfaces, said scanning device arranged to direct said laser beams so as to sweep in a scan direction across said photoconductive surface such that, for each sweep, scan lines written by said laser beams are spaced from one another on said photoconductive surface in a process direction that is nominally orthogonal to said scan direction by a predetermined beam scan spacing; and a controller arranged to maintain a desired image characteristic independent of a selected one of said image transfer rates by controlling said laser beams so as to write image data only at select scan lines that have been identified from candidate scan lines wherein: said image characteristic comprises at least one of a total or average exposure energy of said photoconductive surface for a given image; a rotational velocity of said scanning device is set to a predetermined rotational velocity based upon said selected one of said image transfer rates; said candidate scan lines are defined by positions along said photoconductive surface that are determined at least in part, by one or more of: said selected one of said image transfer rates, said predetermined rotational velocity of said scanning device, the number of independently controllable laser beams that may be swept across said photosensitive surface and their corresponding beam scan spacing; and a process direction spacing between adjacent candidate scan lines for a first one of said image transfer rates is an amount other than double the process direction spacing between adjacent candidate scan lines for a second one of said image transfer rates.