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Counter Rotating Spiral Disks for Scanning

IP.com Disclosure Number: IPCOM000085598D
Original Publication Date: 1976-May-01
Included in the Prior Art Database: 2005-Mar-02
Document File: 2 page(s) / 38K

Publishing Venue

IBM

Related People

Bruce, GD: AUTHOR

Abstract

In Fig. 1, a document 10, which may be a color document, is scanned by lens 12 projecting the document onto the counterrotating spiral disks 14 and 16. Each of the disks 14 and 16 contain four spirals -- one spiral for each primary color and one for black and white. Light passed by the counterrotating spirals strikes four elongated photodiodes 18.

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Counter Rotating Spiral Disks for Scanning

In Fig. 1, a document 10, which may be a color document, is scanned by lens 12 projecting the document onto the counterrotating spiral disks 14 and 16. Each of the disks 14 and 16 contain four spirals -- one spiral for each primary color and one for black and white. Light passed by the counterrotating spirals strikes four elongated photodiodes 18.

The relationship between the spirals on the scanning disks and the photodiodes is shown in Fig. 2. Each of the photodiodes 18A through 18D are scanned by a separate pair of counterrotating spirals. Thus, the intersection of spiral 14A on disk 14 and spiral 16A on disk 16 form a spot scan of a line on document 10 that moves down the length of photodiode 18A. Similarly, spirals 14B and 16B form a spot that scans a line of document 10 and moves down the length of photodiode 18B. The same is true of spirals 14C, 16C and 14D, 16D.

Each of these pairs 14A/16A through 14D/16D of spirals are displaced one element width of the photodiodes, so that each photodiode 18A through 18D sees a different line scan of document 10 at any given instant. Of course, as document 10 is moved in the direction of arrow 20 of Fig. 1 each of the photodiodes will see all of the document on a line scan basis.

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