| 摘要 |
PROBLEM TO BE SOLVED: To easily check that information is embedded in a print with an invisible toner. SOLUTION: When a print 500 formed by printing a code image and a document image in an overlapped state is output, the code image is printed using a special color material. The special color material includes a first material which has absorption wavelength in an invisible region and is invisible, and a second material which has absorption wavelength in a visible region, undergoes a change in its absorption curve under light and becomes invisible. The second material undergoes a change in its absorption curve upon irradiation with visible light for a certain period of time or undergoes a change in its absorption curve upon irradiation with light of a specific wavelength. The code image can be checked with eyes immediately after printing, but after a period of time or by illuminating light of the specific wavelength, the phenomenon that the code image disappears occurs. COPYRIGHT: (C)2007,JPO&INPIT |
