Spot UV is a special finishing in book printing china, and a very important part of printing, in order to keep the UV bright we must follow the standard production process to operate, let's introduce what should pay attention to.

1 Light source: High pressure mercury lamp or metal halide lamp is usually used for Uv irradiation light source, and the output power of the light source should be stable. The output power of high pressure mercury lamp is 80~120 W/cm, to guarantee the curing speed of UV coating & lt;0.5s..

2 Ink: Pay attention to UV paint and ink contact, if necessary apply a layer of bottom glue first.

3 Paper: UV coating is not suitable for simple soaked paper in book printing china. Because the low molecular data in the UV is easy to soak into the paper, the paper becomes dark and even soaked. If you use this paper, you can speed up the printing, and add the number of lamp tubes; you can also first coating the bottom to prevent coating UV coating when the appearance of immersion.

4 Coatings： If the coating layer is too thick, the drying time is relatively prolonged under the irradiation of the same power light source; it will also decrease the water content of the paper, make it brittle and easy to break, and affect the wear resistance of the UV oil layer。

5. Poor brightness： on Poor paper quality or rough appearance, large amount of oil absorption, should be used to high grade paper; If the coating is not uniform or the varnish is too thin, the varnish viscosity should be adjusted. UV varnish should be used special diluent, dilution control at 1:0.5~1.

6. The upper layer of light is white and the coupling density is low. If summer alcohol solvent evaporation fast, should use cool or special diluent; coating yellow, may be the oil coating too thick, viscosity is too large, should reduce viscosity.

7 Poor adhesion. Printing ink layer crystallization or ink additives and anti-skid agents are not appropriate, printing technology should be improved, no or less ink additives