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Copy Quality Enhancement Method and Apparatus

IP.com Disclosure Number: IPCOM000048107D
Original Publication Date: 1981-Dec-01
Included in the Prior Art Database: 2005-Feb-08
Document File: 2 page(s) / 44K

Publishing Venue

IBM

Related People

Queener, CA: AUTHOR

Abstract

Shadowgraph techniques in a xerographic copier/ duplicator enhance the output copy quality from conventional originals (line copy and large areas of solid blacks) by making the characters broader in line copy and the blacks more dense. The characters on line copy are made broader and black areas in general are made more dense by projecting a line screen pattern on the photoconductor through a self focusing fiber-optic array either immediately following or prior to the conventional exposure step of xerography.

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Copy Quality Enhancement Method and Apparatus

Shadowgraph techniques in a xerographic copier/ duplicator enhance the output copy quality from conventional originals (line copy and large areas of solid blacks) by making the characters broader in line copy and the blacks more dense. The characters on line copy are made broader and black areas in general are made more dense by projecting a line screen pattern on the photoconductor through a self focusing fiber-optic array either immediately following or prior to the conventional exposure step of xerography.

The environment of a conventional black and white xerographic office copier employing photoconductor surfaced drum 10 as well as a magnetic brush developer or developer/cleaner (not shown) is assumed. However, the apparatus of Fig. 1 is added just after or just prior to the conventional xerographic exposure step or station. The intensity of small fluorescent exposure lamp 12 is automatically or manually controllable to achieve optimum results. Fiber-optic array 15 is mounted by a light shield 18 to receive light from lamp 12 after passage through line screen 20 and to direct this light onto the surface of drum
10. Note that line-screen 20 is any light filter-type element have a large number of closely spaced line segments that are alternately opaque and transparent.

Fig. 2 shows a schematic voltage profile produced on areas of the photoconductor corresponding to black and white areas of the original in a conventi...