UV ink is also called UV-curable ink, which uses ultraviolet radiation of a certain wavelength to instantly turn liquid ink into a solid state through photochemical reaction. The viscosity of flexo UV inks ranges from 250 to 2000cP (25°C), which is much smaller than that of offset UV inks. At present, UV ink has entered a mature stage, and is recognized by the world as a pollution-free ink variety, and its safety has been recognized by the US Environmental Protection Agency. Flexo UV inks are general-purpose and can be used when printing various substrates such as plastic, aluminum foil, and paper. The printing quality of flexo UV ink is better than that of water-based ink and alcohol-soluble ink, so its development and application have been paid attention to by all aspects.