APERTURE CONTROL OF INTEGRATING CAVITY FLASH LAMP EXPOSURE
Original Publication Date: 1986-Apr-30
Included in the Prior Art Database: 2004-Apr-04
Xerox Disclosure Journal
The figure shows an integrating cavity housing 10 suitable for flash-exposing documents placed on the top (platen) surface. A first, full power flash lamp 12 IS mounted on one wall of the cavity. A second, smaller flash lamp 14 is mounted on a second wall. When a document is in the copying position, an exposure measurement is made by firing lamp 14 and measuring the resultant light by means of photodetector 16. An attenuator I$ is moved into position beneath lens 20 mounted in the cavity floor. Attenuator 18 can be an iris-type aperture, a disc coated with a varying density profile, or a multiple-leafed attenautor. The position of the attenuator controls the amount of exposure at a photoreceptor moving along the focal plane of the lens. Once the attenuator is positioned, lamp 12 is fired to provide full document exposure.