When choosing the UV fluorescent anti-counterfeit printing ink, you must be careful. In generally, when the printing system has produced its complementary color light ink or there exists some printing inks whose wavelengths are longer than the selected fluorescent ink printing ink, this kind of fluorescent ink should not to use or can’t reach a certain amount of anti-counterfeiting effect after use.
The use of UV fluorescent ink type is quite important for packaging anti-counterfeiting effect. If the selection is inaccurate, the anti-counterfeit effect may be not obvious even none. For instance, long and medium wavelengths absorb short wavelengths, according to the color of light color theory and the principle of light absorption.
Now I will analyze fluorescent ink on the specific situation in the actual product structure. If we are printing the colorless fluorescent blue ink on the full version of the golden color, Fluorescent blue ink layer renders blue (B) light under the uv lamp at first, Then it coats with the golden yellow (Y) in the bottom coating layer. From the theory analysis of color additive method, the mixture of yellow and blue light appears white. The complementary color is yellow, and blue light. That is to say, the effect of anti-ounterfeit is not good or in some cases, we don't see any security role.
From the theory of bottom of the light absorption, this is because long wavelength yellow light absorbs part of short wavelength light blue in the spectrum, so we don't see the color which fluorescent blueprint should be present.
Thus we can draw a knot theory, when choosing the UV fluorescent anti-counterfeit printing ink, we must be careful. In generally, when the printing system has produced its complementary color light ink or there exists some printing inks whose wavelengths are longer than the selected fluorescent ink printing ink, this kind of fluorescent ink should not to use or can’t reach a certain amount of anti-counterfeiting effect after use. Therefore fluorescent anti-counterfeit printing ink is used in the production of medicine packing industry, the selection of fluorescent ink is especially important in a variety of printing coating, aimed at the bottom of the printing system material. Moreover, The use of fluorescent ink is more strict for printing process. Due to the particularity of ink system, in generally we should pay attention to consider the following influencing factors in use process:
1. Because the drug packaging and printing technology usually adopts gravure printing, so the selection of the solvent in the gravure printing is very important. solvent dye is one of the important components of the gravure printing, which has solubility and. The volatile speed is to determine volatile type of ink drying speed and is an important factor of printing quality. If the speed of Solvent volatility is slow, the reproducibility is excellent for printing image. But if volatility speed is too slow, thus volatility is not completely finished on the print, the fluorescent ink layer are prone to conglutination, which causes blur anti-counterfeiting image, dirty pages, the anti-counterfeit effect and the overall appearance of the products. On the other hand, if the speed if ink solvent volatilization in the process of printing is too fast, it will produce the phenomenon such as inky white, sticky roller, laying inked layer back problems, which causes the dirty on the back of packaging materials and bright spots overlapping clearly in ultraviolet light F. consumers will feel unsanitary. In severe situation, the phenomenon may affect the next coating and composite process. Due to various printing equipments, operating environment in manufacturers each are not identical, such as the speed of printing machine, the structure of drying system, the characteristic of substrates, indoor temperature and humidity which all should be considered, the solvent used in the process of printing comprehensively consider all factors. Combined with the above requirements, we usually choose two or three different boiling point solvents, which can achieve expected effect of complete security pattern, compared with dissolved parameters of vehicle resin material resin dissolved parameters.
2. The proportion of fluorescent ink in anti-counterfeit printing is quite small. A little UV fluorescent ink can produce a large number of security products. In the production of fluorescent ink products, we should follow the specification of orders as far as possible: the number indicated, the amount of ink reasonably, one-time used up, no unnecessary waste.
Generally, fluorescent ink products cannot be repeatedly used for a long time. One reason is that layout becomes dirty easily. a long solvent washing, fluorescent pigments diluted in ink system, reduce greatly the effect of fluorescent anti-counterfeit. Even under irradiation of ultraviolet light, pictures or text presents a dull glow, which cannot achieve the expected effect of anti-count
