Patent ID: 7151618

Claim:
A halftone dot producing apparatus for producing a plurality of halftone dot data representative of a plurality of monochromatic images in which a color image is separated, by applying threshold matrixes associated with colors to a plurality of multi-tone level image data representative of a plurality of monochromatic images in which a color image is separated, said halftone dot producing apparatus comprising: a phase selection section for selecting a phase between at least a first threshold matrix of said threshold matrixes and a first monochromatic image represented by a multi-tone level image data to which said first threshold matrix is applied; a phase control section for controlling a relative phase between said first threshold matrix and said first monochromatic image to implement the phase selected by said phase selection section; and a data producing section for producing a plurality of halftone dot data representative of a plurality of monochromatic images in which a color image is separated, by applying threshold matrixes associated with multi-tone level image data representative of monochromatic images excepting said first monochromatic image, of said plurality of multi-tone level image data, to the multi-tone level image data representative of said monochromatic images excepting said first monochromatic image, of said plurality of multi-tone level image data, with a phase determined on a fixed basis, and applying said first threshold matrix to multi-tone level image data representative of said first monochromatic image, of said plurality of multi-tone level image data, with the phase controlled by said phase control section.