PURPOSE: To overcome the problem of difficulty of forming a clear and vivid image caused by breaking the equilibrium of electric charge existing between two components to deflect the equilibrium to one pole side when a fluorescent component is introduced into a two component system of a preceding technique.

CONSTITUTION: A single component conductive toner is used for a non-impact printer fluorescent color developing with UV or black light. The toner is constituted so as to express the usual appearance as black characters at the time of being image formed on a web but to fluorescent color develop at the time of being exposed with UV or black light. Then the toner has the availability as security property indicating the alteration or the forgery of a document.