Monday, 17 Feb 2020 21:01 GMT

Ink Technology

Like a pen to paper, ink and print go hand in hand. Without this trusty consumable, the print industry simply wouldn’t be able to exist. Carys Evans takes a look at this technology

The vital ingredient

The use of ink dates right back to many ancient cultures around the world for the purpose of writing and drawing. The earliest ink of all is believed to have derived from a kind of soot as a result of fire-making.

The Egyptians used ink to write on papyrus and Chinese inks are believed to date as far back as three millennia to the Chinese Neolithic period where plants, animals and mineral inks were used. Indian ink was used by Buddhists to compile their sutras using a sharp painted needle. Henna dye is also still traditionally used to temporarily dye hair, skin and fingernails as well as fabrics.

The traditional CMYK colours


In the 15th century, a new form of ink was developed in Europe especially for the printing press by Johannes Gutenberg. This was made of indelible, oil-based dye made from soot, varnish and egg whites. After some trial and error, an ‘oily, varnish-like’ ink using soot, turpentine and walnut oil was created to withstand printing surfaces without creating blurs.

The industry’s lifeblood

Today in printing, there are several different types of ink used for different applications. Aqueous inks are water-based in dye and UV varieties. While pigment inks are generally more colour-fast, they are more expensive and can be less colour consistent with a smaller colour range. Dye-based inks are stronger and can produce more colour but tend to soak into paper and risk bleeding at the edges.

Solvent inks use volative-organic compounds rather than water and are relatively inexpensive and flexible on certain types of surfaces. They are also waterproof, UV resistant and can achieve high-quality colour, and are very durable.

Solvents are used to rapidly dry the ink, but this causes problems with chemicals. These types of inks pose environmental issues and regulatory bodies have set standards for the amount of heavy metals in inks, as well as a shift towards vegetable oils over petroleum oils.

Inkjet technology has become a popular method in digital fabrication


An environmental solution to solvent inks, latex inks have recently been developed and can be used on different surfaces such as vinyl without the production of harmful chemicals. However, this does still use chemicals. Originally developed for the publishing industry, inkjet technology has become a popular method in digital fabrication.

Looking at the state of the ink market, a report by Futurewise Market Research, found that the global printing inks market is forecasted to be valued at more than $25.5bn (£19.55bn) by 2026 while registering a CAGR of 4.5% between 2019-2026.

The report shows that a growing demand from packaging, publication and commercial printing is driving the market, as well as consumer demand for the production of eco-friendly solutions. As a result, water-based inks are expected to lead the market growth with packaging and labels deemed the fastest growing segment due to growing consumer demand for better food packaging.

A growing demand from packaging, publication and commercial printing is driving the market


A period of change

The British Coatings Federation (BCF) is the trade association for printing ink manufacturers in the UK. The group works to protect the interest of the UK printing ink industry by defending the use of biocides and HDDA (hexanediol diacrylate) as a UV technology. The BCF also provides joint lobbying through the industry supply chain through groups such as the Graphi, Print and Media Alliance in the UK and the EuPIA in Europe.

Reflecting on how ink technology has evolved over the years, Peter Baird, non-executive director of the BCF says many things have happened over the past century with two prominent factors being sustainability and a need for increased speed.

Publications are a factor that is driving the market

Baird explains: “The ink industry is committed to further reducing its carbon footprint, wherever technically possible. At the same time it is addressing the continuing challenge of manufacturing products that will successfully transfer to the substrate to be printed, then dry and be available to send to customers at ever increasing turnaround speeds.”

Baird describes digital printing as a “rapidly growing segment” with recent advancements in digital ink technology opening up new possibilities for wide-format signage, commercial and packaging print converters. “The most recent development, UV-LED curing ink for litho, flexographic and digital print applications enables printers to offer high quality on a wider range of substrates, including uncoated papers, and opens up the possibility to print on thin films that may otherwise not be practical to print on.”

Enormous evolution

Barry Moss, research and development manager of global distributing ink and varnish manufacturer, Needham Inks, agrees that digital printing is still the main driver in new ink technologies. He says: “Traditional printing presses will always be a dominant force in the industry, but digital printing will continue to increase its share of the market.

“The increase in demand for inkjet inks has resulted in more exacting specifications for both raw materials and finished inks. Tighter tolerances are now required and expected.”

Ricoh UK is no stranger to the world of inks and provides services for all aspects of the industry. From various inkjet heads, to ‘kits’ which include software for controlling the waveforms that control the nozzles, through to customised modules which strap the heads together into configurations that attach them to other systems with the controllers and ink. This digitises a previously analogue process. The firm also provides full high speed printing systems with end-to-end integration software solutions and round the clock customer service support.

Most recently, Ricoh has developed and invested in resources to create its latex and UV ink formulas. Its latex formula offers a high colour reproducibility and jetting-reliability for inkjet printers, and its UV ink is designed to reduce skin sensitisation which can lead to itching or irritation of the skin.

Developments in UV-LED curing ink for litho, flexographic and digital print enables printers to offer high quality on a wider range of substrates


For Simon Isaacs, national sales director of Ricoh UK, there has been an “enormous evolution” with water-based pigment and dye inks, solvents and latex. Describing how far ink technology has come, he says: “Ink technology has become more versatile over the years, with growing suitability for multiple media types and applications such as indoor and outdoor. It also offers a greener approach which is at the heart of Ricoh.”

Describing the latest developments in ink technology, Isaacs lists UV inks as one of the industry’s latest trends. He says: “They have a low curing print temperature; they reduce energy consumption and offer the same high productivity and possibility to print on a more extensive media range without any issues with media curing temperature.

“Also, from Ricoh’s side, the latest LS inks that we announced on the VC70000 platform this, allow us – in combination with our patented dryer technology – to print a 120m per minute, directly onto litho coated stocks, without the need to pre- or post-treat the paper.”

Addressing the gaps

In terms of gaps in the current market of ink technology, Isaacs describes these as limitless. He says: “Hence our strategy to not only develop solutions where we spot a gap but to open up our technology foundations of heads, controllers and additives to work with others to potentially enter markets we’d not even thought about.

“In general, there is a growing need to increase automation and increase the ability to support production phases via robotics and remote printing control.” He lists packaging, textile and sublimation as the significant upcoming trends.

For Moss, the area which is lacking is that not all water-based inks can provide the quick dry time and high adhesion that solvent-based inks can provide. He predicts that new developments in monomers could provide a space for UV inks to replace solvent-based systems.

O Factoid: In the 15th century, a new form of ink was developed in Europe specially for the printing press O


Looking forward, Baird confirms that research and development is underway to find solutions to these issues. He explains: “A significant area that work has already begun on relates to the need for more recyclability. The growth of UV/LED printing has added to this challenge since UV/LED printed material has traditionally been a headache for the recycling industry.

“The cross-linked ink particles of UV/LED inks can not be fully removed from the substrates, usually leaving dirt deposits in the recycled paper, which are visible and thus reduce the whiteness of the recycled paper. Work is underway to tackle this issue and we expect to see activity around this topic in the coming months and years.”
 

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