Patent ID: 7564586

Claim:
A method for compressing and transmitting image raster data of pages, comprising the steps of: generating a data stream of image raster data from language elements of a graphics language, said data stream containing gray image areas in a form of dither cells whose gray scale values correspond to model dither cells; dividing said image raster data of each one of pages into tiles of a two-dimensional grid, each of said tiles include a plurality of said image raster data; identifying ones of said tiles that contains only dither cells, and marking said tiles that contains only dither cells to produce marked tiles; identifying position data and gray scale values and corresponding model dither cells for said marked tiles as characterizing data for said marked tiles, and transmitting said image raster data of pages including transmitting said characteristic data of said marked tiles for printing of said image raster data without transmitting image raster data of said marked tiles having gray scale values of a predetermined model dither cell.