1. An electrophotographic image forming apparatus having a print engine to form an image onto a printable medium, the apparatus comprising: a storage unit to store a plurality of dot patterns representing print characteristics of the print engine; a data area dividing unit to divide halftoned print data, obtained from image data to be printed on the printable medium, into data areas having the same size as the dot patterns; a pattern extraction unit to extract an appropriate dot pattern from the storage unit with respect to each of the data areas by comparing dots in the data areas to the dot patterns; and a pattern converter to convert the data areas to the appropriate dot pattern.