Book, labels, packages, foils and forms are printed and then coated with protective paint utilizing a number of different methods. The common element among them is that the print ink must be fully dried. This is called curing. This must be done prior to the products can be stacked, folded, cut, or any other kind of processing. The ink can be dried by UV lamps or the IR emitters. The ink can be dried via a combination of both as well. Automated solutions are best adjusted to individual printing process needs. 

Drying, advantages, and disadvantages 

UV inks are a special variety of inks used primarily in professional silk screen printing. These inks dry only when they get exposed to ultra-violet or UV light of proper intensity. A certain amount of time is also needed to make the ink fully dry.. 

UV inks, like all chemical products in the printing industry, has a number of advantages and also disadvantages. One notable advantage is the UV inks do not incorporate dangerous solvents which must undergo evaporation to cure. When UV inks get exposed to strong ultra-violet light, the ink gets cured by a chemical reaction. UV inks are suitable only for professional printers and not for hobbyists. Unlike conventional thermal techniques, UV radiation cures the printing inks and paints within a short span of seconds. 

Strong light not recommended 

The UV ink should print on light colored substrate. The common way to do this is to use silk screen. A few special ink-jet printers come with or can accommodate UV ink cartridges. It is an excellent idea to expose UV ink to strong UV light for a period from one second to three seconds. Exposure to UV light will cure light colored inks within a second. Darker colors take about three seconds of total exposure to be cured. 

You should remove material which in printed with the UV inks from UV light source after a maximum period of three seconds. Excess exposure could result in the inks getting excessively dry. These may result in the inks flaking off from the substrate on which they were printed. It is to be remembered that objects printed with the UV inks must be treated with comparatively more care. This is as these inks are  much thinner than standard inks. The UV inks are susceptible to be damaged by abrasion. Long exposure to the sun can also damage the finished work.