Illuminating system for a copying machine

Claim 1

In a copying machine for producing copies of an original document on light sensitive copy material, an illumination system for illuminating said document to project an image thereof to an exposure plane for the purpose of imaging light sensitive copy material located thereat, said illumination system comprising: a light reflecting chamber having an upper chamber portion formed by upper and lower horizontally extending walls and vertically extending supporting walls, and having a rectangular cross section, the interior surface of said walls being diffusedly reflective to visible radiation, said upper and lower walls each including an aperture therein, said apertures being aligned with respect to each other and the aperture in said upper horizontal wall having a specular reflective, transparent platen mounted therein for receiving said original to be copied, a lower channel-like chamber portion having a cross sectional area less than said upper chamber portion and apertures at opposing ends thereof, the interior surface of said lower chamber portion also being diffusedly reflective to visible radiation, said lower chambEr portion being joined at a first end with said upper chamber at said lower wall with the apertures of said chamber portions being in alignment to provide communication between said chamber portions, lens means mounted at the free end of said channel portion for projecting an image of an original document placed on said platen to said exposure plane, thereby to image said light sensitive copy material positioned thereat, the field of view of said lens means including said platen, and a pair of elongated lamps mounted within said first chamber portion directly beneath and at opposite sides of said platen outside the optical field of view of said lens means to prevent rays from said lamps from passing directly through said lens means thereby to minimize glare at said exposure plane, said lower wall of said upper chamber portion spaced a predetermined distance from said upper wall to provide maximum and uniform illumination of said original receiving platen by light rays reflected from said lower wall, said aperture in said lower wall of said upper chamber portion dimensioned to permit the surrounding lower wall portion to intercept and reflect light rays emanating from said elongated lamps which would otherwise pass directly through said lens, said channel-like member portion having a pyramidal shape and including a pair of opposing side wall members extending substantially in the direction of said exposure plane converging towards said lens means and the remaining interconnecting opposing walls extending substantially in vertical planes substantially perpendicular to the exposure plane and the wall furthest from said exposure plane includes a non-reflective area to prevent light rays which would normally be reflected therefrom to said exposure plane thereby preventing said light rays from impinging on said exposure plane.