Types of Offset Printing Inks

Regular process inks consist of the ingredients above.  However there are many specialty offset printing inks that have unique properties and characteristics.  These are made by means of special additives or modifying the quantities of the basic ingredients. They include the following:

Quick-set inks – The most common type of printing ink used in the world today. For example, many newspapers and business cards are printed this way.  The formula for this ink is a high resin and solvent mixture that absorbs into the paper right after being printed.  When the solvent absorbs into the paper, pigment and resin lay on the surface to dry and solidify (oxidize and polymerize)

Quick-set inks.

Heatset inks* – Also very popular in commercial offset printing.  These inks have a solvent based vehicle with a high boiling point.  After being printed, the substrate passes through an oven and the solvents evaporate from the ink.  This leaves the pigment and resin.  The ink and paper are then cooled and the pigment solidifies inside the resin. 

Heatset printing inks

UV printing inks – This printing ink dries when exposed to a mercury vapor lamp that emits ultraviolet light.  Many commercial printers and even newspaper printers have adopted these inks. Polymers and initiators are added to this ink so that it reacts with the UV light and dries. 

Electron beam inks – These inks are similar to UV printing inks. It contains polymers but does not require expensive initiators like UV printing inks do.  The polymers do not dry, but are chemically changed to solidify the pigment.

Mirror inks – Many in companies make this with a special aluminum powder and resin.  It prints on the back side of a transparent surface. It can be used in offset printing, but is used more often in screen printing.

Fourescent inks – These inks differ in that they have specially derived pigments from organic and inorganic sources.  They have become more popular among offset printers recently as they can be printed over top of colors to enhance them.  They must be printed on white paper to have any effect.

Metalic inks – The pigment of these inks have gold, silver or bronze metallic powders in them. They work well in most offset printing processes and have the usual 4 main components mentioned above.

Wax free inks – These inks have the most common components but lack the additive of wax.  This allows varnishes or other inks to be applied overtop and bind to the printing ink.  This application is mostly used in heatset printing*.

Scratch off inks – This ink is more of a paste than a fluid. It consists of the usual basic components of ink except that it contains rubber. 

Magnetic inks – This offset printing ink only differs in that the pigment can be magnetized.  These inks can have magnetite as their pigment.  However the actual magnetizing of the ink comes after being printed.

Opaque white inks: These inks are derived from titanium oxide which is not a pigment, but gives the desired effect – very high opacity.  This achieves a covering effect in sheetfed offset printing products. Offset printers find that this ink runs quite differently as the particles are larger and harder.  Due to it’s contents, this ink is not appropriate for food packaging unless there is some type of barrier.