Evacuated printing platen
AssigneeInternational Business Machines Corporation
InventorsFloyd A. Gregory, Donald F. Manning, William Oranchak, Joseph J. Student, deceased
Life of this patent
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Abstract
Printing platen for positioning a recording medium such as paper which includes an evacuated chamber having a slotted face plate for attracting, holding and guiding the paper. Slots are arranged parallel to each other and the direction of paper travel, and the vacuum attraction causes temporary deformation of the paper so that the slots can effect guiding and tension on the paper during advancement. Effective platen length can be varied to accommodate different paper widths.
Claims4
Apparatus for positioning a web of recording medium comprising:
- tractor means engaging opposite edges of said web for moving said web;
- a chamber extending across the width of said web;
- a face plate serving as one wall of said chamber adjacent said web, said face plate having a plurality of parallel slots extending longitudinally in the direction of motion of said web;
- and
- means for evacuating air from said chamber to thereby attract said web against said face plate to provide frictional restraint during the motion of said web, with said slots being formed to provide decreasing frictional restraints from one edge of said web to the other.
In a machine for feeding a web and having means for pulling said web from a source of supply past a recording station, platen means comprising:
- a chamber extending across the width of said web;
- means for evacuating air from said chamber;
- a face plate at said station serving as one wall of said chamber adjacent to the plane of travel of said web, said face plate having a plurality of parallel slots through which air is drawn into said chamber, said slots extending longitudinally in the direction of web motion and being formed in said face plate to gradually decrease the frictional restraint imposed on said web from one edge to the other by vacuum attraction.
Dependencies are inferred from the claim text.