| 摘要 |
PROBLEM TO BE SOLVED: To readily discriminate a printed matter from a forged one by formulating a light-storing material in an ink used for ink jet recording to form an image on a recording medium by jetting the ink. SOLUTION: Preferably, the light-storing material is made primarily of a compound represented by M-Al-O, M-Al-O-B or M-A-Si-O wherein M represents a rare earth element; and A represents an alkaline earth metal element, and should preferably have a particle size of 50 to 200 μm, a specific surface area of 50 to 300 m2/g, and a DBP(dibutyl phthalate) oil absorption of 50 to 200 cc/100 g. The light-storing material may be dispersed in water with the aid of a dispersant, to which an additive and/water is added, if necessary, with or without further addition of a colorant, or the light-storing material may be added to an ink for ink jet. The light-storing material should preferably be compounded in an ink or a pattern-forming solution in an amount of 0.1 to 5 wt.%. |
