International Business Machines Corporation

William M Doumas

Jean-Claude Fouere

Ralph S Colby

Robert M Rectenwald

A printing machine with control device for identifying solid areas to be imaged. The printing machine is regulated on a picture element (pel) basis to produce pels representing the interior of solid areas with an intensity sufficient to create a relatively large development vector and to produce non-solid area pels, such as the edges of solid areas, text, and line pels with an intensity sufficient to create a smaller development vector. In that manner, toner deposit densities are balanced for solid interiors, the edges of solids, test, and lines. A control method is provided for establishing the desired line stroke width, toner density, and exposure level for an electrophotographic printer, and thereafter establishing the exposure level needed to balance toner density in the solid areas with the line toner density.

Printing machine with toner density balance in solid areas and line

A method for improving the quality of raster imaging in which an array of pels is selected having a pattern of filled and unfilled pel positions. In the selected array, an assumed line is determined based on its pel pattern by comparing the pel pattern of the selected array with respect to a plurality of predetermined pel patterns each having a predetermined associated line and angle. When a match is found, the assumed line of the selected array is determined as the associated line of the matched predetermined array. The intensity of the pel at the center of array is selected in accordance with the angle of the line. The line, at the predetermined angle, is positioned to bisect the pel to be enhanced. Intensity is determined by the relative areas of the portions of the bisected pel.

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Boulder, CO, United States of America

William M Doumas