Browse Prior Art Database

Facsimile Compatibility with Different Resolution

IP.com Disclosure Number: IPCOM000081995D
Original Publication Date: 1974-Sep-01
Included in the Prior Art Database: 2005-Feb-28
Document File: 2 page(s) / 48K

Publishing Venue

IBM

Related People

Fowler, RL: AUTHOR

Abstract

Compatibility is established between a 240 line/inch facsimile machine and machines with resolutions of 96 and 88 lines/inch. Another article of interest also entitled "Facsimile Compatibility with Different Resolutions", R. L. Fowler, appears in this issue of the IBM Technical Disclosure Bulletin, Vol. 17, No. 4, September 1974, pp. 1104 and 1105.

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Facsimile Compatibility with Different Resolution

Compatibility is established between a 240 line/inch facsimile machine and machines with resolutions of 96 and 88 lines/inch. Another article of interest also entitled "Facsimile Compatibility with Different Resolutions", R. L. Fowler, appears in this issue of the IBM Technical Disclosure Bulletin, Vol. 17, No. 4, September 1974, pp. 1104 and 1105.

The facsimile printer shown has a drum 1 for mounting paper 2 and is set up for 240 lines/inch resolution (i.e., during one revolution of the drum, the lead screw 3 advances the carrier 4 1/240 inch). Such a printer is assumed to be receiving signals from an 88 line/inch scanner. To make the printer compatible with the scanner, the printer's lead screw is slowed down by 10/11 and the scanner signal is repeated for three revolutions of the printer drum 1.

For signals from a 96 line/inch scanner, lead screw 3 is slowed down by 10/12 and the signal repeated three times. For 64 lines/inch signals, lead screw 3 is speeded up by 5/4 and the signal repeated three times. As an example of the speed change, the 88 lines/inch is used as follows: 240 lines/inch over 3(88) lines/inch = 240 over 264 = 10 over 11 = 0.090909.

This scheme always uses the 3-to-1 ratio, which helps when a 240 line/inch scanner talks to an 88 lines/inch printer, for example because only the center scan of the three can be called "the signal", while the other two outside scans can be ignored.

By judiciously...