Double-resolution optical system for electrophotographic printer

摘要

Light emitted from an array of light-emitting elements in an electrophotographic printer is transmitted through a birefringent plate that deflects light polarized in a first plane but does not deflect light polarized in a second plane perpendicular to the first plane, and through a polarization switching device that is controlled by an electrical signal so as to selectably transmit light polarized in either the first plane or the second plane. The transmitted light illuminates a photosensitive medium. Each light-emitting element can illuminate two dots on the photosensitive medium, depending on the state of the polarization switching device, thereby doubling the dot resolution.