| 摘要 |
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).
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