Friction-feed plotter with laterally-movable drive roller, and related method for plotting on sheets of different widths

An apparatus for plotting on sheets of different widths, comprising:

• first means for supporting a sheet;
• second means spaced apart from and movable in a first coordinate direction relative to the first means for plotting on the sheet;
• third means rotatably mounted on a first shaft and defining an abrasive surface for rotatably engaging a first marginal portion of the sheet and driving the sheet in a second coordinate direction;
• and
• fourth means rotatably mounted on a second shaft spaced laterally relative to the third means and defining an abrasive surface for rotatably engaging a second marginal portion of the sheet and further driving the sheet in the second coordinate direction, wherein at least one of the third and fourth means is movable laterally relative to the other for engaging first and second marginal portions of sheets of different widths;
• fifth means for rotatably driving the third means to thereby drive the sheet in the second coordinate direction;
• and
• sixth means for rotatably driving the fourth means to thereby further drive the sheet in the second coordinate direction;
• wherein the fourth means and sixth means are both movable laterally relative to the third means.

A method for plotting on sheets of different widths on a plotter having a sheet-supporting surface, and a plotting tool spaced apart from and movable in a first coordinate direction relative to the sheet-supporting surface, comprising the following steps:

• providing a first drive roller rotatably mounted on a first drive shaft and defining an abrasive surface for engaging a first marginal portion of a sheet and driving the sheet in a second coordinate direction;
• providing a second drive roller rotatably mounted on a second drive shaft and defining an abrasive surface for engaging a second marginal portion of the sheet and further driving the sheet in the second coordinate direction;
• moving at least one of the (i) the first drive roller and a first drive motor, and (ii) the second drive roller and a second drive motor, in the first coordinate direction relative to the other drive roller and motor to align the first drive roller with the first marginal portion of the sheet and align the second drive roller with the second marginal portion of the sheet;
• frictionally-engaging the first and second marginal portions of the sheet with the first and second drive rollers, respectively, and rotatably driving the first and second drive rollers to drive the sheet in the second coordinate direction;
• and
• moving the plotting tool in the first coordinate direction over the sheet to create relative movement at the interface of the plotting tool and sheet and thereby plot on the sheet.