The factors that influence the printer in the decision-making process when purchasing a new ink technology also include price, durability, adhesion, colour brightness and coverage. What’s more, the ink type must perfectly match the application you are looking to provide your customer.
Ink plays a key role in technology and the standard of print quality. Printers need the ink to deliver outstanding and consistent performances, with minimal disruption to the production floor.
Here we provide a lowdown on the key ink technologies:
Print technologies: An overview
Types
Colorants
Pigment inks are used more frequently than dyes because they are more color-fast, but they are also more expensive, less consistent in color, and have less of a color range than dyes.
Pigments
Pigments are solid, opaque particles suspended in ink to provide color.[1] Pigment molecules typically link together in crystalline structures that are 0.1–2 µm in size and comprise 5–30 percent of the ink volume.[1] Qualities such as hue, saturation, and lightness vary depending on the source and type of pigment.
Dyes
Dye-based inks are generally much stronger than pigment-based inks and can produce much more color of a given density per unit of mass. However, because dyes are dissolved in the liquid phase, they have a tendency to soak into paper, making the ink less efficient and potentially allowing the ink to bleed at the edges of an image.
To circumvent this problem, dye-based inks are made with solvents that dry rapidly or are used with quick-drying methods of printing, such as blowing hot air on the fresh print. Other methods include harder paper sizing and more specialized paper coatings. The latter is particularly suited to inks used in non-industrial settings (which must conform to tighter toxicity and emission controls), such as inkjet printer inks. Another technique involves coating the paper with a charged coating. If the dye has the opposite charge, it is attracted to and retained by this coating, while the solvent soaks into the paper. Cellulose, the wood-derived material most paper is made of, is naturally charged, and so a compound that complexes with both the dye and the paper’s surface aids retention at the surface. Such a compound is commonly used in ink-jet printing inks.
An additional advantage of dye-based ink systems is that the dye molecules can interact with other ink ingredients, potentially allowing greater benefit as compared to pigmented inks from optical brighteners and color-enhancing agents designed to increase the intensity and appearance of dyes.
A more recent development in dye-based inks are dyes that react with cellulose to permanently color the paper. Such inks are not affected by water,alcohol, and other solvents.[citation needed] As such, their use is recommended to prevent frauds that involve removing signatures, such as check washing. This kind of ink is most commonly found in gel inks and in certain fountain pen inks
Water based inks
If a printing business is looking to move into fine art and photo quality like products, dye or pigment based inks are generally used for these types of applications. Water carries the colourant in both inks, which comprises of tiny particles in dye inks. Dye inks produce more detailed images with smooth tones and vibrant colour reproduction, but they are not water and UV light resistant. Therefore, they are mainly used for indoor environments and short term use in UV lighting.
Pigment inks have slightly bigger particles, are more stable in UV light and are water resistant. Their particles settle into the fibres of paper, canvas or similar substrates. Window displays, posters, pop-up or longer term promotional jobs, together with short term outdoor projects, are some of the possible applications that can be explored with pigmented inks. They can last for several months before fading, or even for some years if protected against sunlight.
Solvent Ink?
Simply put, solvent ink is a relatively inexpensive type of ink made to work in inkjet printers. In the world of ink the term solvent is used to mean any ink that is, in fact, not made with a water base.
Uses
Solvent ink’s greatest application is in the printing of products that are to be used outdoors because of its ability to adhere to non-absorbent materials. Solvent ink also has the advantages of being fade proof, water proof and scratch resistant. These qualities enhance its usefulness in outdoor printing.
Components
There are three parts to solvent ink: the carrier fluid, pigment and resin. Technically, solvent ink refers only to the oil-based carrier portion of the ink that keeps the other components in liquid form and once applied to a surface through jetting dissolves. Pigments used to produce color in solvent ink are applied in powder form to produce the best quality color and they are adhered to the printing materials by mean s of resin which both makes the color stick and protects it from damage.
Eco-Solvent
Eco-solvent is a form of the non-water based ink that is made from ether extracts taken from refined mineral oil; the cognitive implication of the term “eco” which brings to mind the idea of an ecologically sound product is an inaccurate assumption when applied to this form of solvent ink because neither the material used in making it nor the creation process are ecologically conscious choices. Eco-solvents are also known as soft or mild ink; this form makes the creation of a reliable printer easier because of its slow dry time and the need for multiple heaters in the printer.
Aggressive Solvent
Aggressive solvent Ink, known too by hard or true solvent, is a fast drying form of the ink which uses a quickly absorbing solvent formula, allows prints to be made on surfaces that cannot handle a lot of heat. Aggressive solvent ink is also more scratch resistant and weatherproof than eco-solvent.
Costs
The cost for both the mild and aggressive forms of solvent ink are comparable when purchased in ink cartridges, but manufactures of printers made for use with the aggressive form have made bulk ink insert options that overtime save on ink costs in order to offset the fact that aggressive ink printers use 10 percent more ink than mild ink printers.
UV INKS
A type of radiation-curing ink that dries, or “sets,” with the application of ultraviolet light. UV curing ink vehicles are composed of fluid oligomers (small polymers), monomers (light-weight molecules that bind together to form polymers), and initiators that, when exposed to ultraviolet radiation, release free radicals (extremely reactive atoms or molecules that can destabilize other atoms or molecules and start rapid chain reactions) that cause the polymerization of the vehicle, which hardens to a dry ink film containing the pigment. UV curing inks are designed to replace heatset inks whose solvents emit potentially toxic gaseous emissions. However, UV curing inks are as much as three times the cost of regular heatset inks, and are used only in specialty printing, such as liquor cartons, cosmetic packaging, metal decoration, screen printing, and flexography.
The most common configuration of UV curing equipment is a mercury vapor lamp. Within a quartz glass tube containing charged mercury, energy is added, and the mercury is vaporized and ionized. As a result of the vaporization and ionization, the high-energy free-for-all of mercury atoms, ions, and free electrons results in excited states of many of the mercury atoms and ions. As they settle back down to their ground state, radiation is emitted. By controlling the pressure that exists in the lamp, the wavelength of the radiation that is emitted can be somewhat accurately controlled, the goal being of course to ensure that much of the radiation that is emitted falls in the ultraviolet portion of the spectrum, and at wavelengths that will be effective for ink curing. UV radiation with wavelengths of 365:366 nanometers provides the proper amount of penetration into the wet ink film to effect drying. (See Photo-Reactive Vehicle.) A newer variation of radiation curing inks, Electron Beam (EB) Curing Inks, have some advantages over UV curing inks, but although the formulation of the inks is less expensive, the EB curing equipment is more expensive.
Latex inks
Up until recently, HP had the exclusive patent for latex inks. However, Mimaki’s latex ink, launched just before FESPA Digital 2012, has significantly opened up this market space. This new development could see even more manufacturers creating new latex ink technologies in the near future.
Latex inks produce odourless and high quality prints across a wide range of media, delivering eye-catching indoor and outdoor applications. Latex inks are scratch and water resistant and can print on low cost and uncoated substrates, such as paper and polyester. Wall coverings, POP displays, soft signage, posters and banners are just a few examples of what it’s possible to achieve with these inks.
There’s no need for an air purification system, because latex inks emit extremely low levels of VOCs. This process evaporates the ink system and causes the latex polymer particles to form a continuous polymer layer that adheres to the print media and create a durable colourant film.
Water is a major component of latex inks, offering benefits to production environments because it doesn’t require special handling and is not toxic, flammable or combustible. Latex inks are positioned as a viable and eco-friendly alternative to solvent and eco-solvent inks. They provide many of the benefits of solvent-ink technology—such as outdoor durability—without imposing the typical environmental, health, and safety restrictions.
Mimaki’s latex ink is an aqueous, odourless resin based technology which has reasonable sustainability credentials. Their latex inks boast similar features and environmental advantages to HP inks. They also have the additional benefit of white ink to the traditional four colour process. The white ink increases the spectrum of applications and provides more versatility, with the flexibility to print on a wide range of media including transparent PET, window decoration and shatterproof window film.
As the above demonstrates, print technology is a complex topic, and one that a single feature cannot explain fully. We are in the process of building a “knowledge bank” of backgrounders to help you increase your understanding of an area that is going to remain fundamental to PSPs’ drive for increased profit and productivity.
We live in exciting times in the world of print technology. The innovation we are seeing is transforming the way we do business. The opportunities to expand into new areas by providing customers with product solutions, is a real possibility.
UV flatbed printing technology 