Spatial Information Theory A Theoretical Basis for GIS

An improved document support system for use in a character by character printer of the type that employs a rear striking hammer to drive the document, at the printing position, into contact with a selected symbol on a rotating type font. Typically, the type font would be on the surface of a constantly rotating wheel. In application, a front paper guide is provided which limits and defines the normal spacing between the document and the type font in the area of the printing position; the said spacing normally being quite small. A rear paper guide is supported by the hammer structure and is spring biased towards the front paper guide. Both paper guides include cutouts or openings so that the printing hammer can drive the document towards the selected character of the font to effect a printing action. The paper guides cooperate to maintain the document in a fixed location, relative to the type font, and serve to compress the document pack which may comprise an original document, carbons, and multiple copies, so that there are no separations, or air pockets, therebetween at the printing position. The paper guides enable the production of a more uniform appearing print of improved quality. Supporting and holding the document in a known position allows a constant portion of the kinetic energy of the print hammer to be available for affecting a print action, thus increasing the quality of the print.