Patent ID: 6731401
Filing Date: 2004-05-04
Classification: G06K

Abstract:
A printing system with a printing head that successively forms dots along scanning lines in a predetermined scanning direction on a printing object and records an image through a distribution of dots based on an error diffusion technique, said printing system comprising:input means for inputting print data including tone information regarding an image to be recorded by a pixel unit; a single line buffer storage having a plurality of storage areas and a total capacity to a number of pixels included in only one scanning line, each said storage area storing a sufficient to store only a cumulative error of pixels in a single scanning line, the cumulative error allocated to each pixel according to the error diffusion technique; diffused error registration means for registering said cumulative error into each of said storage area; corrected tone data computing mean s for computing corrected tone data with respect to a target pixel that is subjected to determination of formation or non-formation of a dot, based on tone information of said print data regarding said target pixel and said cumulative error regarding said target pixel and being registered in a storage area corresponding to said target pixel; density error computing means for calculating a difference between a printing density corresponding to said corrected tone data and a printing density realized by formation or non-formation of a dot as a density error; error distribution determination means for determining distribution of said density error into non-processed peripheral pixels in the vicinity of said target pixel with predetermined weights; storage control means for storing errors allocated to adjacent pixels following said target pixel on an identical scanning line in a primary scanning direction into storage areas of said single line buffer storage corresponding to said adjacent pixels following said target pixel, and storing errors allocated to pixels existing on a next scanning line at positions corresponding to said target pixel and preceding pixels before said target pixel in the primary scanning direction into storage areas said single line buffer storage corresponding to said target pixel and said preceding pixels before said target pixel, based on the distribution of said density error determined by said error distribution determination means; and updating means for clearing the error allocated to the target pixel and storing the error allocated to the pixel existing on the next scanning line at the position corresponding to the target pixel.