During the offset print,uv ink shows weak polarity,the emulsion phenomenon appears if water and ink are not balanced well.which will cause ink film become non-transparent.then directly affect the transmittance of Ultraviolet,slowing down the UV ink curing speed further.as a result of that.the inside of ink film can not be cured entirely.the scratch and peeling comes out on the surface when the printed products are folded and rubbed together under this condition.
Thus，controlling the water and ink ratio is an important factor to ensure the UV ink curing quality.because the adhesion force is stronger between relative big Uv ink molecules，the ink can resistant the water stronger.therefore,in order to reduce the emulsion of UV ink，we must ensure the principle that the water should be least to ensure the colors to be brilliant、ink drop thick and firm、net dot is unambiguous and rich.