LED signature elimination in specular-mode LED illumination having a light diffuser between an illuminator array and an image bearing surface

摘要

A system for detecting reflectance from an image bearing surface in a printer or electronic copier includes an illuminator array, positioned adjacent to the image bearing surface, comprising a plurality of discrete illuminator elements that are spaced in a linear arrangement; a light diffuser positioned between the illuminator array and the image bearing surface, the light diffuser being positioned with respect to the illuminator array to receive the light beams emitted by the illuminator elements and to diffuse the light beams for transmission to the image bearing surface at an incidence angle; and a linear sensor array positioned adjacent to the image bearing surface such that specular and diffuse portions of the light beams reflecting off the image bearing surface at a reflectance angle bearing are received by the sensors.