Patent ID: 7616343

Claim:
An image data conversion apparatus comprising: a color space information acquiring unit that acquires color space information of a pixel contained in image data; a saturation determination unit that determines the saturation of the pixel whose color space information is acquired on the basis of the color space information acquired by the color space information acquiring unit; a color space information conversion unit that converts the color space information of the pixel whose saturation is determined not to exceed a predetermined threshold value by the saturation determination unit out of the pixels contained in the image data into the color space information to be printed with black toner by a predetermined image forming apparatus; wherein the saturation determination unit determines that the saturation of the pixel which has color space information: | R−G|<Th 1 , |G−B|<Th 2 , |B−R|<Th 3 where the color space information acquired by the color space information acquiring unit is represented by RGB signals including R value, G value and B value, and Th 1 , Th 2 and Th 3 represent predetermined threshold values, does not exceed the predetermined threshold value; an image type determination unit that determines the type of the image of the image data whose color space information is acquired by the color space information acquiring unit; and a threshold value setting unit that sets the predetermined threshold value on the basis of the type determined by the image type determination unit.