Patent ID: 6433807
Filing Date: 2002-08-13
Classification: B41J

Abstract:
An identification card printing system adapted to improve contrast of an original image represented by an array of pixels each having a pixel level representing an intensity of the pixel, the system comprising:a substrate feeder mechanism adapted to transport a substrate along a printing path; a thermal printhead in line with the printing path and having a plurality of resistive heaters arranged in a line on a substrate; a microcomputer; a memory; and a printer driver stored in the memory and including instructions executable by the microcomputer to perform steps of: (a) selecting a pixel of the pixel array; (b) calculating an adjusted pixel level for the selected pixel based upon its pixel level and at least one proximal pixel level defined as the pixel level of a pixel located proximate to the selected pixel; and (c) repeating steps (a) and (b) for substantially all of the pixels of the pixel array to form an adjusted pixel array that represents an adjusted image having greater contrast than the original image, wherein some of the adjusted pixel levels constitute increases from their previous pixel levels and some constitute decreases from their previous pixel levels.