Abstract: A self contained, demountable, unitary modular optical system for a Solid State Laser Diode Printer/Copier utilizes a folded light beam path whereby laser light is collimated through a compound four element collimating objective lens assembly, passed through a cylindrical lens focussing the beam to a horizontal line image onto the facets of a rotatable polygon mirror assembly. The beam is then passed through a cylindrical meniscus lens focussing the beam to a small dimension in the scanning or horizontal direction. A pair of cylindrical-spherical lenses with the corresponding centers of the cylindrical and spherical surfaces located near the facet of the polygon provide cross-scan focussing in the vertical direction as well as approximating a pair of toridal lenses. Horizontal and vertical spot size can thus be independently focussed.