How Much Do You Know About The Most Common Types Of Printing Inks On The Market Today?

How much do you know about the most common types of printing inks on the market today?

The history of ink goes back a long way, according to Wikipedia, the earliest known surviving documents date back to the 26th century BC.

Today, there are many types of printing machines, each with its own advantages and markets. Letterpress, which was a staple of printing until the 1940s, is rarely seen today. The following are the main types of inks used in today's printing presses:

Offset (paste) ink

Letterpress ink was eliminated by offset ink. While letterpress inks are printed from sheet, offset presses can print large numbers of pages with roll-to-roll or sheet-fed presses. The three main types of offset printing inks are sheetfed, thermoset and coldset inks. Inks are usually oil based and dry after printing. However, there is an increasing emphasis on using renewable resources, such as soy products.

Until the 2010s, offset printing was the dominant printing process for about seven decades. They are ideal for publications; the coldest (or news ink) is the primary ink for newspapers, phone books, etc. They consist of carbon black and a binder unless color pigments are required.

Magazines can often be printed on heatset presses (or publication gravure). These are roll-to-roll presses capable of running at 2,500 feet per minute. Also, thermoset inks are similar in composition to coldset inks.

However, with the widespread use of the Internet, the newspaper and magazine market has been affected. News and sales of thermoset inks were affected accordingly.

This brings us to sheetfed ink. Sheetfed inks appear in magazines and annual reports and have declined in recent years. However, since the sheets are fed into the printing press, they can also be thicker substrates, allowing the production of folding cartons. These presses can now run up to 20,000 sheets per hour.

Packaging has proven to be a growing market for sheetfed printers. Sheetfed inks are usually UV cured. According to a recent study by Smithers, offset printing is facing change as technology redefines the industry.

Liquid ink for packaging

Liquid ink, mainly flexo and gravure ink, is the dominant technology for packaging, and flexo is the dominant process. Flexo and gravure printing machines are roll-to-roll printing machines. Depending on the substrate and application, the inks cover all areas of water-based, solvent-based and UV technology.

For example, since solvent-based inks are dried to remove the solvent, they are often found on plastic substrates and more often on flexible packaging. In contrast, water-based inks are the primary inks for corrugated paper because they can be dried to corrugated board or kraft paper. Digitization is gaining ground in these markets, but we'll get to that shortly.

As for the composition of liquid ink, the main difference between paste ink and liquid ink is the type of resin and additives. Paste inks use hydrocarbon resins, while liquid inks will use acrylic, nitrocellulose, polyamide, and other types of resins.

digital ink

Digital printing is the fastest growing area of printing. It has taken over a market previously dominated by screens (billboards, tiles) and offset printing (direct mail). It is also growing in markets such as textiles and folding cartons. Digital ink has also expanded into the corrugated printing market.

The key to the development of digital printing is the technological advantage; it is only on digital printing presses that small batches can be produced cost-effectively, whether it be personalized mailings, prototypes or custom projects, or regional or targeted events. There are hybrid presses that combine digital technology with flexo or sheetfed, allowing printers to personalize projects or add unique tracking codes.

As far as the composition of digital inks is concerned, a variety of colorants can be used. Dyes were originally used for most applications, but pigments have become more common than ever because of their lightfastness. The key is that the pigment must be properly dispersed, as the viscosity required to jet the ink without clogging the printhead is critical. For this reason, traditional resins are not commonly used. In terms of traditional additives, surfactants, defoamers and rheology modifiers are commonly used in inkjet inks.

Energy Curable Ink

Energy-curable inks have made considerable progress in packaging and digital printing over the past two decades. These are broken down into Ultraviolet (UV), Electron Beam (EB) and, more recently, UV LEDs, whose use is growing rapidly as it does not require the mercury-based lamps used in traditional UV.

The advantages of energy curing are reflected in the curing process. The ink cures instantly when exposed to UV, UV LED or EB light. This reduces the footprint, as there is no need for an oven to heat ink, solvent capture equipment, or a huge space for inventory to dry. UV inks tend to be more expensive than water-based or solvent-based inks. Because there are no solvents or volatile organic compounds (VOCs), UV and EB are considered more environmentally friendly technologies.

The binders used in energy-curable inks differ from conventional inks. For UV and UV LEDs, photoinitiators are essential to crosslink the ink to the substrate. EB is cured using acrylic monomers.

Conductive ink

Conductive inks have grown into a sizable niche for ink suppliers. Conventional PV is the largest market for conductive inks because the backsheet is screen printed. Sensors are an evolving field.

Screen printing is the main process, followed by inkjet. It depends on the application. For example, screen printing allows manufacturers to apply a thick layer of conductive ink or paste, which increases conductivity. In contrast, if the idea of a printer is to use a small amount of ink in a targeted area (such as a conductive trace), the printer may use inkjet.

The most interesting difference in composition is the type of conductive material used for these inks and pastes. Silver is by far the most common because it conducts electricity very well. In terms of cost, copper oxide would be ideal, but the disadvantage is that copper will oxidize very quickly. Carbon-based inks are making progress in this area.