Raster scanner with a selectable spot dimension

A marking machine comprised of:

• a photoreceptor having a photoconductive surface which moves in a cross-scan direction;
• a charging station for charging said photoconductive surface to a predetermined potential;
• a raster scanner assembly for exposing said photoconductive surface to produce a first electrostatic latent images on said photoconductive surface by sweeping a modulated laser beam across said photoreceptor in a fast scan direction which is substantially perpendicular to said cross-scan direction;
• a first developing station for depositing developing material on said first electrostatic latent image so as to produce a first toner image on said photoconductive surface;
• and
• a transfer station for receiving said first toner image from said photoconductive surface and for transferring said first toner image onto a substrate;
• wherein said raster scanner assembly includes:
• an electronic subsystem for producing both image data and a spot size control signal;
• a laser assembly for generating a polarized laser beam having a first beam dimension, wherein said polarized laser beam is modulated in accord with said image data;
• a variable aperture assembly operatively connected to said electronic subsystem and receiving said laser beam from said laser assembly, said variable aperture assembly for changing said first dimension of said laser beam in accord with said spot size control signal;
• a rotating polygon having a plurality of facets receiving the spot size controlled laser beam from said variable aperture assembly, said rotating polygon for sweeping said spot size controlled laser beam in a sweep plane;
• and
• a scan lens receiving said laser beam from said rotating polygon, said scan lens for focusing said spot size controlled laser beam onto said photoconductive surface.