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Variable Traverse Control for Document Reader With Line Marking Capability

IP.com Disclosure Number: IPCOM000075242D
Original Publication Date: 1971-Aug-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 2 page(s) / 50K

Publishing Venue

IBM

Related People

Anderson, TH: AUTHOR [+2]

Abstract

Optical reader 10 includes a transport for incrementing a document 11 and for stopping it at lines of print 12 which are to be read. Scan head 13 then moves across print line 12 under the control of reversibly driven lead screw 14. Timing marks 15-18, in two marginal tracks on document 11, identify the lines to be read. The sensing of a mark in either track by photodetectors 19, 20 will stop the document and start scan head 13.

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Variable Traverse Control for Document Reader With Line Marking Capability

Optical reader 10 includes a transport for incrementing a document 11 and for stopping it at lines of print 12 which are to be read. Scan head 13 then moves across print line 12 under the control of reversibly driven lead screw 14. Timing marks 15-18, in two marginal tracks on document 11, identify the lines to be read. The sensing of a mark in either track by photodetectors 19, 20 will stop the document and start scan head 13.

The use of two timing-mark tracks also controls the beginning and ending positions of the path traversed by scan head 13. To achieve this format control, photodetectors 21,22 are mounted on guide shaft 27, detectors 23,24 on shaft 28, and detectors 25,26 on shaft 29. Detectors 21-26 are manually positionable along their respective shafts 27-29. Mask 30 is mounted to scan head 13 such that its occultation of each detector produces a signal indicating the location of head 13. Other forms of detectors, such as proximity detectors, may be substituted for photodetectors 21-26 and mask 30. Since the use of two timing- mark tracks provides three possible mark combinations, up to three preassigned line locations may be specified. If, for instance, mark 15 appears by itself, the presence of a signal from photodetector 20 and the absence of a signal from detector 19 causes head 13 to begin scanning print line 12 at a location determined by the preset position of detector 21, and to terminate scanning (and increment document 11 to the next line) determined by the position of detector
22. When mark 16 is detected, the presence of a signal in detector 19, but no signal in detector 20, causes head 13 to scan between the position of detector 23 and the position of detector 24. Subsequently, t...