White vector adjustment via exposure using two optical sources

An electrophotographic image forming device, comprising:

• at least one photoconductor unit;
• and
• a laser operative to form a latent image on said photoconductive unit by selective optical illumination of areas of said photoconductive unit to be developed by toner;
• and
• a non-laser optical source operative to selectively optically discharge areas of said photoconductive unit not be developed with toner.

A method of adjusting the voltage of a photoconductive unit relative to an associated developer roller in an image forming device, comprising:

• uniformly charging the surface of said photoconductive unit to a first voltage;
• selectively optically discharging the surface of said photoconductive unit, with a first laser source generating coherent optical energy at a first wavelength, to a second voltage at predetermined locations to be developed by toner;
• and
• biasing the surface of said developer roller to a third voltage that is intermediate to said first and second voltages;
• and
• selectively optically discharging the surface of said photoconductive unit, with a second laser source generating coherent optical energy at a second wavelength, to a fourth voltage at selected locations not to be developed by toner, said fourth voltage being intermediate to said first and third voltages.