An image processing device includes a detecting unit and a pre-processing executing unit. Before image data is generated for a printer, the detecting unit detects first density information per image element, and detects, for the image elements, whether or not overprinting is set. If the detecting unit detects that the overprinting is set at an image element and the image element has a basic color of which first density information is set 0%, the pre-processing executing unit executes a pre-processing which changes the first density information of the image element into second density information which is greater than 0% and which is capable of being recognized as white by the naked eye.