Automatic exposure control

Details Automatic exposure control Automatic exposure control

1976-06-01

1978-06-06

Hix, L. T.

Photocopying

Projection printing and copying cameras

Illumination systems or details

355 69, 250205, G03B 2778

Patent

active

040933768

ABSTRACT:
The disclosure relates to an automatic exposure control system for use in a document recorder of the type which makes a photographic reproduction of each of a series of documents and which has a document transport for feeding the documents along a predetermined path and an exposure station within the predetermined path including an exposure light source for illuminating each document as each document is presented to the exposure station to facilitate the photographing of the documents. The automatic exposure control system controls the illumination intensity of the exposure light source in response to the reflectivity of each document to assure proper exposure of each document. It includes a first light source arranged relative to the predetermined path in advanced relation to the exposure station relative to document travel for projecting light onto the documents, a first light sensitive element arranged relative to the predetermined path for receiving the light reflected from the documents originating from the first light source for providing a first control signal having a magnitude directly related to the intensity of the reflected light, a feedback arrangement coupled between the first light source and the first light sensitive element for controlling the intensity of the first light source in response to the first control signal to render the intensity of the reflected light received by the first light sensitive element substantially constant, and control means coupled to the exposure light source and responsive to the light output intensity of the first light source for controlling the illumination intensity of the exposure light source as each document is presented to the exposure station.

REFERENCES:
patent: 3728023 (1973-04-01), Stevko et al.
patent: 3775009 (1973-11-01), Collins
patent: 3947117 (1976-03-01), Basu et al.

Affiliated with

Also associated with

Rating

Automatic exposure control does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Automatic exposure control, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Automatic exposure control will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-1490222