Platen to print head gap adjustment arrangement

摘要

A system for automatically adjusting the print head gap of an impact printer, particularly for paper stocks of differing thicknesses and multi-layer forms, provides for measurement of an absolute distance between an undeflected platen position and a home position of the print head. Paper stock thickness is measured by measuring the distance to the home position from a position of the print head when a predetermined force is exerted by the print head against the platen. Since a similar measurement is made when paper stock is not present in the printer and using the same force against the platen, platen flexure is removed as a source of error and a standardized force is available for compression of the paper stock during measurement. Improved accuracy is achieved at high speed while avoiding the use of position encoder/decoder arrangements. A wider range of manufacturing variations in printer geometry and rigidity can be accommodated with uniformly improved print quality.