Plotter paper sizing system

摘要

A method and apparatus for providing automatic paper edge finding and sizing in a graphics plotter system having a platen over which paper is moved longitudinally to create one axis, penholding apparatus moved transversely across the platen and the paper to create the other axis, and a controlled raising and lowering mechanism connected to the penholding apparatus for lowering a pen being held therein into contact with, for raising it from contact with the paper, and for providing a relative vertical position value signal. Vertical sensing apparatus is connected to the penholding apparatus for sensing the top surface of the platen. First logic is operably connected to the vertical sensing apparatus and to receive the vertical position value signal from the controlled raising and lowering mechanism for calculating and saving a plurality of values indicating the distance to the platen top surface at a plurality of spaced points across the platen. There is edge sensing apparatus carried by the penholding apparatus and cooperating with the vertical sensing apparatus for sensing the edges of paper, third logic for automatically moving the paper from end to end over the platen and for saving the positional values of the ends of the paper as found by the edge sensing apparatus, and fourth logic for automatically moving the penholding apparatus from side to side over the paper and for saving the positional values of the side edges of the paper as found by the edge sensing apparatus.