1. An image processing apparatus which performs, when output image data is generated from input image data having a plurality of color components, a process for superimposing a pixel having the plurality of color components with respect to an edge extracted based on the input image data, comprising: a first resolution judgment section for judging whether or not resolution of input image data is not less than a predetermined value; a first conversion section for converting resolution of the input image data to resolution less than the predetermined value when the first resolution judgment section judges that the resolution of the input image data is not less than the predetermined value; a process judgment section for judging whether or not the process for superimposing a pixel having a plurality of color components is performed with respect to an edge extracted based on the image data after conversion by the first conversion section; a determination section for determining a color component of the pixel to be superimposed when the process judgment section judges that the process for superimposing is performed; a second conversion section for converting resolution of pixel data based on the color component determined by the determination section to the resolution of the input image data; and a superimposing section for performing a process for superimposing the input image data on the pixel data after conversion by the second conversion section.