IMAGE FORMING APPARATUS, IMAGE FORMING METHOD, AND PRINTED MATERIAL

An image forming apparatus (IF) includes an image forming unit (GU) and developing containers (51). The image forming unit (GU) includes developing stations (18) to form an image on a print medium with toners, based on input image data. The developing containers (51) contain the toners and are attachable to and detachable from the developing stations (18). The developing containers (51) include a first developing container containing a first toner and a second developing container containing a second toner having a higher luminescence intensity under invisible light than the first toner. The first toner and the second toner are toners that form an image having a higher luminescence intensity under the invisible light than under visible light. The image forming unit (GU) adheres the second toner to the print medium before adhering the first toner when the image forming unit (GU) superimposes the first toner and the second toner one atop another on the print medium.