Theoretical Analysis and Realization of Beam-Splitting Laser Scanning System

Abstract

Beam-splitting laser scanning systems can halve the required number of light sources and lead to low-cost and space-saving color electrophotographic apparatus. However, the presence of ghost lights can result in imaging errors in the system. There are two methods for preventing ghost lights. One method is to shift the timing of the ghost light from the image region. Another method is to remove the ghost light using optical elements. We analyzed the exposure timings of full-color organic photoconductors (OPCs) and clarified a condition in which the ghost light is suppressed theoretically. To satisfy the condition, it is necessary to slow the print speed and increase the size of the laser scanning system. Therefore, we devised an optical system to remove the ghost light and realize a beam-splitting laser scanning system without slowing the print speed and increasing the system size. By utilizing this new system and 40-ch (40-channel) vertical-cavity surface-emitting laser (VCSEL) arrays, we delivered high-speed, high-resolution, low-cost, and compact color multi-function printers (MFPs).