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Optical Document Scanner Apparatus for Alternatively Single-Side Scanning of Full-Size Documents Or Two-Sided Scanning of Half-Size Documents

IP.com Disclosure Number: IPCOM000120832D
Original Publication Date: 1991-Jun-01
Included in the Prior Art Database: 2005-Apr-02
Document File: 3 page(s) / 105K

Publishing Venue

IBM

Related People

Olson, PL: AUTHOR

Abstract

Disclosed is an optical scanning device that uses a common document transport and common electronics to function in two modes - one to scan either one side of a full-size document, or both sides of a half-size document in a single pass.

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This is the abbreviated version, containing approximately 52% of the total text.

Optical Document Scanner Apparatus for Alternatively Single-Side
Scanning of Full-Size Documents Or Two-Sided Scanning of Half-Size
Documents

      Disclosed is an optical scanning device that uses a
common document transport and common electronics to function in two
modes - one to scan either one side of a full-size document, or both
sides of a half-size document in a single pass.

      Fig. 1 shows the basic optical components of the scanner.  Two
scanning arrays A and B are used to span the width of a full size
document D.  (Or, a single scanning array with a tap at the half-way
point could be used.)  On the opposite side of the transport path,
another scanning array C spans half the width of a full-size
document.  This array C is positioned opposite array A but is staged
at a different point in the transport path, not directly opposite A,
in order to avoid potential "bleed-through" problems when
simultaneously scanning the front and back.  Also shown are
illumination sources E, and F for the front and back scanning arrays.
Not shown are the required optics for proper focusing and pel (or
dot) resolution.

      For single-side, full-size document scanning, arrays A and B
are used, and the scanner functions basically like other page
scanners.

      For two-sided scanning of smaller documents (width up to half
the full page size), arrays A and C are used.

      Fig. 2 shows how the basic mode selection logic is configured.
The data from arrays B and C is input to a selector G.  The mode
select signal selects data from array B if the scanner is in
full-page scanning mode, or from array C if the scanner is in
two-side, half-size scanning mode.

      Array A is shown positioned in the transport "ahead" of array C
(to avoid "bleed through" as mentioned previously). The data from
array A is then processed bef...