Drying offset printing ink has taken on several different directions. Each method has different advantages.
Heastset drying – This is a form of evaporative drying whereby the ink passes through a gas oven and the solvents in the ink reach a flashpoint and evaporate. Once evaporated, the inks are cooled down by means of chilling rollers and the pigment solidifies in the resin.
See this article for a detailed explanation of this process.
Electron beam drying – This is the method of drying or curing offset printing inks by means of an electronic beam. These lamps are installed after each printing unit and cured immediately after leaving he printing unit.
Ultraviolet drying – Otherwise known as UV curing, this method employs ultraviolet light to cure inks. The printing inks are especially formulated to reach to this frequency of light and solidify.
Absorption drying – This is the most common method of drying for sheetfed and newspaper printers. The vehicle is absorbed into the paper and the film rests on the top. Drying can take days or weeks depending on the printing ink type. There is also a small amount of evaporation drying as the ink is exposed to the air.
There are many drying processes for offset printing inks. The method used really depends upon the desired finished product, the speed of production, and economy of the process. Each type of offset printing ink is formulated to facilitate different types of ink drying.
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