IMAGE PROCESSING DEVICE, PRINTING CONTROL DEVICE, IMAGE PROCESSING METHOD, AND RECORDED MEDIUM

摘要

Image data is converted into data of an expression type according to presence/absence of a dot for each group of a predetermined number of rasters adjacent to each other. The gradation error caused in each pixel of the last raster of a raster group is dispersed to peripheral pixels and stored in a first storage unit. For the first raster of the next group next to the above last raster, it is judged whether or not a dot is present by reading the gradation error from the first storage unit, and the gradation error caused as a result of the judgment is stored in a second storage unit the reading/writing speed of which is faster than that of the first storage unit. For the other rasters than the first raster, in parallel with the conversion of the first raster into a dot string, it is judged whether or not a dot is present in each pixel of the other rasters while reflecting the gradation error caused in each pixel of the first raster, and the other rasters are converted into dot strings.