Image forming device which can form an image by printing a plurality of pixel unit areas which are composed of multiple sub pixels

摘要

An image forming device which can form an image by printing a plurality of dots based on an image information that contains a plurality of density data corresponding to a plurality of pixels defined by the fractionalization of the original image, and which can express the density of an image by controlling the number of dots to be printed within a predetermined tone unit area. The image forming device includes a threshold pattern generator for generating a threshold pattern which is a repetition of a basic pattern including a predetermined number "L" of thresholds, a comparator for comparing respective density data with a predetermined number "M" of thresholds selected from all "L" of the thresholds in which "L" is not an integer multiple of "M", and for producing a predetermined number "M" of print data corresponding to the respective density data; and a printer for printing on a printing sheet dots corresponding to the "M" print data in a line along a main scanning direction.