Image forming apparatus, image forming method, and printed material

An image forming method comprising:

• adhering, to a print medium, a first toner contained in a first container of a plurality of containers attachable to and detachable from a plurality of developing stations of an image forming unit of an image forming apparatus, the image forming unit being configured to form an image on the print medium with toners contained in the plurality of containers;
• superimposing, on the first toner adhered to the print medium, a second toner contained in a second container of the plurality of containers;
• and
• superimposing, on the second toner, a third toner contained in a third container of the plurality of containers such that the first, second, and third toners are adhered to the print medium in this order,
• the second toner having a higher luminescence intensity under invisible light than the first toner and third toner having a higher luminescence intensity under invisible light than the second toner,
• the first toner, the second toner, and the third toner being toners that form an image having a higher luminescence intensity under the invisible light than under visible light,
• wherein the first toner is an invisible blue toner that forms a blue image having a higher luminescence intensity under the invisible light than under the visible light;
• the second toner is an invisible red toner that forms a red image having a higher luminescence intensity under the invisible light than under the visible light;
• and the third toner is an invisible green toner that forms a green image having a higher luminescence intensity under the invisible light than under the visible light.

A printed material comprising:

• a print medium;
• and
• an image formed with a first toner, a second toner, and a third toner superimposed one atop another in this order on the print medium,
• wherein the second toner has a higher luminescence intensity under invisible light than the first toner on the print medium,
• wherein the third toner has a higher luminescence intensity under the invisible light than the second toner on the print medium,
• wherein the first toner, the second toner, and the third toner are toners that form an image having a higher luminescence intensity under the invisible light than under visible light, and
• wherein the first toner is an invisible blue toner that forms a blue image having a higher luminescence intensity under the invisible light than under the visible light, the second toner is an invisible red toner that forms a red image having a higher luminescence intensity under the invisible light than under the visible light, and the third toner is an invisible green toner that forms a green image having a higher luminescence intensity under the invisible light than under the visible light.