UV inks contain opaque solid pigments. These pigment particles strongly absorb ultraviolet light, making it impossible for UV light to reach the surface of UV inks to pass directly through. . There are about a thousand pigment particles in a 2μm UV ink. A UV light beam has to be reflected many times and absorbed many times before it reaches the bottom of the UV ink and the UV light oil. Therefore, the UV light Must have enough strength to reach the bottom of the ink layer to cure the UV ink. If the light intensity is not enough, only the surface of the ink layer can be solidified, and the solidified layer strongly absorbs ultraviolet rays, so that the bottom ink can not be ultraviolet light, and cannot be cured. This is like cooking outside the end of the cooked rice, and then with more ultraviolet radiation, the ink will not be cured.
The UV varnish is a transparent body, and there is no obstacle for the ultraviolet rays to shine from the upper layer to the lower layer, so the ultraviolet light intensity required for curing is weak.
According to the above analysis, the curing UV ink needs to use the focus reflector, fast curing with high power lamps; and curing UV Varnish can use astigmatism, parallel light reflector, low power lamp slow curing, like gentle fire grilled fish The effect is better. ("Printing Technology")