An image processing apparatus includes a document image generating section, a medium ID generating section, a correspondence information storing section and an image output section. A document image generating section generates a document image based on a managed data in the apparatus. A medium ID generating section generates a medium ID for identifying a medium on which the document image is printed. A correspondence information storing section stores correspondence information by which the managed data and the medium ID are correlated with each other. An image output section outputs an image in which a code image indicating the medium ID is superimposed on the document image.