Patent ID: 6701847
Filing Date: 2004-03-09
Classification: B41C,B41F,B41M,B41N,B41P

Abstract:
A method of varying the ink density of a full tone in printing within a rotary printing machine with an ink application system that supplies a constant quantity of ink, said method comprising the steps of:setting a binary image on a printing plate, the binary image including a basic raster of raster points for variable-area image information on the printing plate, the raster points determining the area coverage of the basic raster; and superimposing the basic raster on a fine microraster such that the area coverage of the basic raster on the printing plate is reduced by a desired variation from the ink density of a full tone of the basic raster corresponding to a percentage within the range including 0% to 100%, the microraster being produced in regions of the area of the binary image on the printing plate by laser exposures for producing a fine pattern of holes in the basic raster which reduces the area of coverage of the basic raster by a proportion which corresponds to the desired variation in the ink density from the full tone of the basic raster, wherein a desired characteristic that is different from the real characteristic of the basic raster is used as a basis for determining the microraster.