US 7,093,939 B2Granted

High-speed continuous linear film transport system

AssigneenextScan, Inc.

InventorsKurt Breish, Dennis Sand

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Abstract

A stable, continuous, high-speed roll film media path is established between supply and take-up film reels. Supply and take-up path segments isolate a core transport path section from significant non-linear forces, thereby enabling continuous, high-speed, high-accuracy scan line imaging of the media. The supply and take-up path segments each operate to continuously maintain open decoupling loops in the film media while accurately controlling the speed, tension and alignment of the film media as transported through the core transport path section. A microcontroller operates two motor driven capstans to establish the film media speed and tension within the core transport path section. Optical sensors provide feedback to the microcontroller in managing two additional motor driven capstans to maintain the decoupling loops. The film media within the core transport path section is thereby isolated from frictive, inertial, and skewing forces that could otherwise degrade the media imaging.

Claims17

Dependent claims

A continuous film transport assembly providing a stable, high-speed core transport path for scanning roll film media transported between supply and take-up reels, said continuous film transport assembly comprising:

a) a first transport path section providing for the establishment of a first decoupling loop in film media as continuously transported through said first transport path section;
b) a core transport path section coupled to continuously receive film media from said first transport path section, said core transport path section including a first capstan driven by a first speed controlled motor to define a fixed transport speed for film media as transported through said core transport path section, a second capstan driven through a friction slip connection by a second speed controlled motor to define a fixed tension on film media as transported through said core transport path section, wherein the direction of rotation by said second speed controlled motor being counter to the transport direction of film media transported through said core transport section, and wherein said core transport path further provides for the passive transport of film media between said first and second capstans;
and
c) a second transport path section coupled to continuously receive film media from said core transport path section, said second transport path section providing for the establishment of a second decoupling loop in film media as continuously transported through said second transport path section;
whereby variable forces associated with the supply and take-up reels are isolated by said first and second decoupling loops from said core transport path.

2 more elements

A continuous feed roll microfilm media transport system enabling high-speed, high-accuracy scan line digitization of document images present on the media, said transport system comprising:

a) a supply reel tensioning system operable to provide a continuous supply of microfilm media;
b) a take-up reel tensioning system operable to take-up a continuous supply of microfilm media;
and
c) a microfilm gate system coupled between said supply and take-up reel tensioning systems, said microfilm gate system including first and second microfilm media transport path segments disposed respectively at the feed and take-up ends of a microfilm gate transport path segment, wherein said first and second microfilm media transport path segments respectively maintain controlled, open-air decoupling loops in the microfilm media, wherein the height of said decoupling loops is maintained within predetermined tolerances by speed adjustment of first and second motor driven capstans located at the outer ends, relative to said microfilm gate transport path segment, of the first and second microfilm media transport path segments, wherein said microfilm gate transport path segment includes third and fourth motor driven capstans located at the ends of said microfilm gate transport path segment that exclusively define the speed and tension on microfilm media transported between said third and fourth motor driven capstans, said microfilm gate transport path segment further including first and second passive rolling scroll bars located between said third and fourth motor driven capstans and define a gate region within which microfilm media is supported for digitization of document images and wherein the speed of said third and fourth motor driven capstans is controlled independent of the speed of said first and second motor driven capstans such that the speed of said third motor driven capstan accurately determines the speed of the microfilm media through said microfilm gate transport path segment.

1 more element

A method of performing a high-speed, continuous digital scan of a linear film media that enables accurate digital reproduction of images from the film media at high transport speeds, said method comprising the steps of:

a) decoupling non-linear forces operative on a linear film media by creating and maintaining open loops in said linear film media at the entry and exit of a core film media path;
b) controlling the speed of said linear film media through said core film media path using closed-loop speed control of a media drive capstan;
c) maintaining a constant tensioning force on said linear film media as said linear film media traverses a film gate portion of said core film media path using a tensioning capstan driven by a closed-loop speed controlled tensioning motor through a friction slip connection;
and
d) supporting said linear film media at the entry and exit of said film gate portion with scroll bars disposed in a gate plane parallel to and raised above a base plane containing said media drive capstan and said tensioning capstan.

2 more elements

Dependencies are inferred from the claim text.