US 5,326,011 AGranted

Reduced-skew web drive between rollers of differing coefficients of friction, particularly to transport paper, metal or film in a laser imager

AssigneePrintware, Inc.

InventorsDonald V. Mager, Daniel A. Baker

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Abstract

A web of material, typically paper, metal or film and most commonly roll photographic plate material, passes between a first, driven, roller made from material with a high coefficient of friction, typically neoprene rubber, and a second, driven, roller made from material with a low coefficient of friction, typically metal or nylon. The high-friction drive roller (only) is positionally adjustable. The web is driven straight ahead, without appreciable undesirable steering or skew, over a broad range of adjustments of the separation, and the parallelism, between the two rollers. The web motion is responsive substantially to only the high-friction drive roller, and the web speed may accordingly be regulated, including so as to be maintained highly uniform, in response to the drive roller (only).

Claims19

Dependent claims

In an imager for marking a web of photosensitive medium with light, the imager having a plurality of pairs of opposed rollers for guiding the web through the imager with at least one roller of each pair serving to drive the web, the improvement wherein at least one of the plurality of pairs of opposed rollers comprises:

a first roller with a surface made of a first material having a predetermined coefficient of friction;
and
a second roller, opposed to the first roller so that the web may past between the first and the second roller, with a surface made of a second material having a coefficient of friction relatively lower than the predetermined coefficient of friction;
and wherein at least three succeeding ones of the plurality of pairs of opposed rollers comprise:
a first roller pair located first in the direction in which the web is driven where the surface of the first material is disposed to a first side of the web;
a second roller pair located second in the direction in which the web is driven where the surface of the first material is disposed to a second side of the opposite to the first side;
and
a third roller pair located third in the direction in which the web is driven where the surface of the first material is again disposed to the first side of the web.

5 more elements

Multiple pairs of opposed rollers for guiding a web of photosensitive medium through an imager that serves to mark the medium with light, each pair of the multiple pairs of opposed rollers comprising:

a first roller with a surface made of a first material having a predetermined coefficient of friction;
and
a second roller, opposed to the first roller so that the web may past between the first and the second roller, with a surface made of a second material having a coefficient of friction relatively lower than the predetermined coefficient of friction;
and succeeding ones of the multiple pairs of opposed rollers comprising:
a roller pair where the surface of the first material is disposed to a first side of the web;
alternating in line with the movement of the web with
a second roller pair where the surface of the first material is disposed to a second side of the web opposite to the first side.

4 more elements

Dependencies are inferred from the claim text.