US Patent 8009338 Image processing apparatus

An image processing apparatus that reduces a color of a document image to be printed. An image generation unit scans a document to generate image data. A hue determination unit determines a specific hue included in the image data and a hue becoming a complementary color of the specific hue. A color reduction unit reduces a color of the image data based on the specific hue and the hue becoming the complementary color of the specific hue. An output unit outputs the image data whose color is reduced on a recording medium. Image data that is of a hue in a predetermined range from the hue becoming the complementary color is replaced with the hue becoming the complementary color, and image data that is outside of the predetermined range is replaced with the specific hue.