Process for printing a halftone image

Claim 1

A process for printing a half tone image from original image data represented as a plurality of respective halftone steps of a halftone dot of a model image, said process comprises the steps of: (a) defining a plurality of processing flames each having corresponding positions for image data represented by a plurality of adjacent halftone dots, wherein each of the positions are assigned a position number; (b) adopting the original image data in accordance with a selected one of the plurality of processing frames in correspondence to the positions of the plurality of adjacent halftone dots; (c) associating a corresponding reference pattern with each of the halftone steps, wherein the reference pattern has a plurality of predetermined color step values in correspondence to an arrangement and the position numbers of the positions of the selected one of the plurality of processing frame; (d) obtaining corresponding color step values from the image data adopted in step (b) in accordance with the corresponding reference pattern for each of the position numbers of the positions of the selected processing frame, the color step value contained in the corresponding reference pattern associated with the halftone step at a position with the corresponding position number is associated with a print position corresponding to each of the image data; and; (e) printing color dots with graduated color gradations at the print positions to produce the halftone step, wherein the color gradation of each of the color dots is adjusted in accordance with the color step value corresponding to the print position.