Diffuse light collector which minimizes streak artifacts

In a laser scanning apparatus, including means for scanning a laser beam across a substantially horizontally directed scanning region and means for translating an information medium through said scanning region, a diffuse light collector located below and adjacent to said scanning region for receiving light transmitted through said information medium, said collector comprising:

• a horizontally disposed, hollow collector member extending the length of said scanning region, having diffusely reflecting interior surfaces forming a diffusely reflecting light cavity and having an elongated slot adjacent to said laser scanning region for receiving light from said information medium into said cavity, wherein said hollow member has a slanted light impingement opposite said slot and a lower region below said face, whereby dirt which falls into said cavity through said slot, cascades off of said face into said lower region;
• and
• a photodetector communicating with said collector cavity for detecting light received into and diffusely reflected by said light cavity.