Patent ID: 6072591
Filing Date: 2000-06-06
Classification: B41B,H04N

Abstract:
A printing system, including a processor preparing documents for printing at a color printer, said documents defined by plural separations, each separation including a set of color separation image signals describing optical density therein with c density levels, for a destination color printer rendering density with d density levels, comprising:a color printer;a source of separation image signals representing optical density within the separation at one of c levels, for a discrete area therein;a halftone processor receiving a group of separation signals from each separation from said source, said group of separation signals defining optical density for corresponding discrete areas of the document at c levels in each separation, including:a first calculating arrangement having an integration function of at least two combinations of said group of separation signals receiving as inputs a group of separations of a separation signal so as to determine the number of image signals that should be printed for comparing an output of the integration function to a series of threshold values for said discrete area of the document,a second calculating arrangement, responsive to said determined number of image signals that should be printed, and the values of each separation image signal, and determining which printer colorants should be deposited at said discrete area of the document, and generating print signals responsive thereto,an error distribution arrangement, determining any differences between said received image signals and said print signals, and adding the determined difference, if any, to image signals corresponding to areas adjacent to said discrete area, to be processed;an image processor directing signals processed at said halftone processor to said printer to print a halftoned image.