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Film Flattening Device

IP.com Disclosure Number: IPCOM000094732D
Original Publication Date: 1965-May-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 2 page(s) / 42K

Publishing Venue

IBM

Related People

Helle, RB: AUTHOR [+2]

Abstract

In order to accurately photoelectrically scan or record an image on photographic film, the film must be held flat to within a close tolerance without touching the emulsion side of the film. Conventionally, this is accomplished by forcing the nonemulsion side of the film against the surface of a backup plate having vacuum holes in it mounted flush with the film. However, this results in pockets or ripples on the film tending to distort the recording and it is necessary to switch off the vacuum to advance the film.

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Film Flattening Device

In order to accurately photoelectrically scan or record an image on photographic film, the film must be held flat to within a close tolerance without touching the emulsion side of the film. Conventionally, this is accomplished by forcing the nonemulsion side of the film against the surface of a backup plate having vacuum holes in it mounted flush with the film. However, this results in pockets or ripples on the film tending to distort the recording and it is necessary to switch off the vacuum to advance the film.

This apparatus includes a film gate containing glass plate 1 recessed with respect to surface 3 of the film by a distance slightly less than the allowable tolerance of film flatness. The resulting air chamber between the glass and the film is vented to a vacuum system through vacuum ports 5 to allow evacuation of the entire area. Since the area of the chamber is relatively large with respect to the film, a vacuum less than 1. 5 inches of water is sufficient to draw the film flat against the glass surface as shown in dotted form in the upper drawing, section AA, while the resulting pressure from the emulsion side holds the film flat against the glass plate.

Due to the low vacuum employed, the force exerted upon the film when it is drawn against the surface of the glass plate thus has a negligible influence on the ability to thread or advance the film through the gate, no damaging effect is produced upon the glass or the film. As a c...