Two-beam scanning optical system

摘要

A two-beam scanning optical system comprising two laser beams each having a polarization characteristic, a first polarization beam splitter for compounding the two laser beams into one laser beam, a rotary polygonal mirror for scanning the compounded laser beam, a second polarization beam splitter for separating the compounded laser beam into two laser beams, and a lens system for focusing the separated laser beams onto a surface of a sensitive drum of a laser printer and onto a surface of an original document to be read, respectively, so that said two separated laser beams scan the respective surfaces of the sensitive drum and the original document.