Patent ID: 6850339

Claim:
A method for enhancing the resolution of black image regions rendered at a resolution of color image regions, the black image regions and color image regions being represented by pixels, the black image regions and color image regions having a first resolution, the first resolution being lower than a maximum black printing resolution of a printer, the method comprising: generating black pixels and color pixels at said first resolution; separating the black pixels from the color pixels to form a black pixel field: for each original pixel of the black image region of the black pixel field having the first resolution, multiplying said pixel in two dimensions to obtain a first array of pixels, so as to represent the original pixel by a plurality of target pixels in the first array; forming a sub-array of the first pixel array that includes said target pixels and a plurality of neighboring pixels constituting a pixel window; applying the pixels in the pixel window of the sub-array to a logic circuit having a plurality of logical conditions; creating enhanced resolution pixels by modifying the target pixels based on whether said pixel window meets one of the plurality of logical conditions; and printing said enhanced resolution pixels at a second resolution as well as said color pixels at said first resolution.