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Copier Illumination Apparatus

IP.com Disclosure Number: IPCOM000083499D
Original Publication Date: 1975-Jun-01
Included in the Prior Art Database: 2005-Mar-01
Document File: 2 page(s) / 38K

Publishing Venue

IBM

Related People

Maddox, RA: AUTHOR

Abstract

This copier illumination apparatus uses a flat-ribbon filament to reduce the illumination magnification associated with an elliptical cylinder reflector.

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Copier Illumination Apparatus

This copier illumination apparatus uses a flat-ribbon filament to reduce the illumination magnification associated with an elliptical cylinder reflector.

In the illumination system of Fig. 1, which employs an elliptical cylinder reflector 10, shown in cross section and in a front view in Fig. 2, if a coiled cylindrical filament light source 11 is used it is difficult to collect a large portion of its light, and to concentrate it into a narrow footprint 12 at the plane 13 of a document to be illuminated. This is true because this type light source radiates equal intensity in all directions, as viewed in Fig. 1, and the size of the coiled filament becomes magnified at plane 13. To reduce these magnification effects a larger reflector must be used, or a narrow aperture must be provided in the light path prior to plane 13, thereby reducing the illumination efficiency. .

If light source 11 is replaced with a similar light source 14 having a flat-ribbon filament, as in Fig. 3, the magnification is reduced. As with Fig. 1, the light source is located at one focus of the reflector 10 and plane 13 is located at the other focus. The ribbon filament 14 is oriented to lie on axis 15 of the reflector 10.

This type of light source does not radiate equally in all directions, but rather has a radiation pattern as shown in Fig. 4. As a result, at points on the reflector where magnification is large,
i.e., near apex 16, the reflector 10 sees a low lig...