Patent ID: 7480063

Claim:
A printing system that eventually converts original image data to be printed into dot data as data in unit of dots and prints an image in unit of raster lines as arrays of dots created according to the dot data, said printing system comprising: a print head that has multiple dot formation elements to create dots on a printing a print head control module that prints each raster line included in the image by at least two dot formation elements; an image data conversion module that converts the original image data into convened data, which is in a form prior to expansion into dot data corresponding to the multiple dot formation elements and is in a more compressed form than the dot data; a convened data storage module that stores the convened data; a data expansion module that successively reads out the stored convened data and expands the converted data into dot data for actuating the multiple dot formation elements; and an output module that outputs the expanded dot data to said print head control module, wherein said image data conversion module collects a preset number of multiple pixels in the image into each pixel group and specifies a number of dots to be created in each pixel group based on the image data, so as to obtain the convened data, said convened data storage module stores data representing the specified number of dots to be created in each pixel group as the convened data, and said data expansion module converts the stored data representing the specified number of dots into the dot data and comprises a dot data storage module, which simultaneously stores the converted dot data at least once with respect to M pixel sets included in each pixel group, where M is an integer of not less than 2 but of less than N, which is a total number of pixel sets included in the pixel group.