Digital Inkjet Printing and Printing Development

In the past 10 years, the printing industry has undergone considerable changes, most notably the introduction of new digital printing technologies and complex processes adapted to a range of different printing applications. However, when the printing process becomes more mature, people tend to forget that the printing ink market has also had to change to adapt to those new automatic printing technologies.

In many cases, with the development of new digital printing technologies, ink is no longer treated as a single commodity, but as an integral part of the printing process. Today, no matter in the printing of promotional brochures or large-scale outdoor posters, or in the printing of simple barcodes or complex packaging trademarks, a considerable amount of time and resources are being devoted to the development of ink to optimize the printing process. The operation, while providing the best terminal effect.

Some time ago, it was a turbulent period for the Indian ink market. The pressure of price drop and environmental protection issues posed a heavy burden on manufacturers. From the point of view of transmission, printing methods such as screen printing, offset printing, flexo printing, and gravure printing do not rely on the use of certain special inks to run their printers. Therefore, in the past it was decided which printer to buy. Therefore, what kind of printing press was decided in the past is mainly influenced by the price, and it is not always determined by the quality.

Digital technology has begun a new trend because technologies such as digital inkjet have a great dependence on the type of ink used. This feature of the printing process means that printer manufacturers must now work closely with the ink manufacturers to develop an ink that can optimize the printing technology and the performance of the substrate material and specifically adapt to the individual needs of the end user.

With the accelerated development of the ink printing market, there is currently a large series of ink products that can be adapted to each type of printer and give the best results for specific applications. In the digital inkjet printing market, there are now four major types of inks that are widely used, namely waterborne, oil based, solvent and UV curable inks.

The value of this type of ink is that they can be used for the flexibility of ever-increasing substrate materials and for applications on high-performance printers. Each ink type is different and has its own set of unique properties. It is this distinction that separates ink from each other and shows that printing ink is not just a printing tool.

For example, oil-based inks are pigment systems based on substantially dry, low-volatile oils. They are only suitable for a limited base material, namely paper and board, and are ideally suited for packaging printing applications. This type of ink is rapidly "dried" on the porous permeable material by absorption, but due to the properties of the oil, it does not "dry" on the non-porous permeable or semi-porous permeable sheet-based material. Therefore, the oil-based printing ink is mainly used in industrial printing applications, such as outsourcing box bar code printing, etc., and has an excellent drying time in the printing nozzle, thereby greatly reducing the maintenance needs of the nozzle. For Merlin Alpha Dot series printers equipped with XAAR printheads, oil-based inks can be used to print extremely clear and precise color or black-and-white quality effects on different base materials, from wood to plasterboard.

In wide-format printing applications such as outdoor billboards, banners, etc., the use of oil-based inks is limited due to the lack of surface-smoothing base materials capable of quickly absorbing ink, despite the use of inexpensive absorbent papers to print traditional ones. Posters can also get good results.

In comparison, solvent-based inks are relatively inexpensive and can be printed directly on non-painted substrate materials such as vinyl banners, self-adhesive vinyl, mesh fabrics, and paper, and therefore have a wide range of applications in picture printing. The use of high-quality pigments can provide good outdoor UV stabilization without the use of a film, and the ink's volatile characteristics can also make the dried ink film lighter.

DGI's Wistarjet Digital Inkjet Printer uses solvent-based printing ink to achieve high picture quality in the printing of large banners specifically for outdoor use.

This type of printing ink took time and effort in formulating a balance between the drying time characteristics of the base material and the drying time during printing. Daily maintenance is also required for the print head, and the print head must be covered when not in use. In addition, when non-porous, pervious sheet-based materials are used, preheating may also be required to speed up drying and prevent ink from forming mottled areas in high-density areas. These show that the ink-based printing ink can indeed provide high-quality images, and is still a popular ink selection for many digital presses.

However, solvent printing ink also brings some environmental problems. Due to their characteristics, they have a high level of volatile organic compounds and can have an adverse effect on the environment. Therefore, the use, storage, and disposal of solvent-based inks need to be controlled, and they must also be used under good ventilation conditions.

Compared to solvent-based inks, UV-curing inks are increasingly becoming a popular alternative, and it is becoming a major new-generation platform for digital presses. These machines are designed to be used in batches. Printing is performed on a flexible and rigid base material. Light, tough, and long-lasting effects can also be obtained on non-painted substrates, so they no longer need to be applied outdoors. The combination of UV-curing inks and digital stage printers allows us to print more reliable, efficient, and ultimately faster, outdoor media such as poster boards, billboards, banners, etc. Technology has stimulated the printing industry because of its tremendous impact and its increasing application.

For example, Inca has decided to choose a UV curing ink system for its Inca Eagle 44 platform digital press. This machine has been designed to print promotional materials. Since UV inkjets are primarily composed of 100% acrylic-based densities, Eagle printers can print on a wide range of materials including cardboard, wood, and plastics such as PVC.

As the first digital printer to print on cylindrical objects, Canpet Printomat 400 also uses UV-curing inks and XAAR's piezoelectric drop-on-demand inkjet technology to make them on beverage cans. The direct printing became a reality. Its short-lived, variable-printing capabilities make this machine more adaptable and personalized, and attractive for those packagers who seek market competitive advantage and try to print directly on the product. .

In addition, UV-cured inks contain no volatile organics and remain in a liquid state until solidified by ultraviolet light. This allows the showerhead to have a long dry-out time and low maintenance requirements. When the ink is exposed to ultraviolet light, it can be "dried" on the substrate material almost instantaneously. However, UV-cured inks suffer from surface "oxygen inhibition", resulting in stickiness after printing. Higher ink film weight can also result in incomplete curing, which in turn can cause adhesion failure. The use of light sources through fine recipes, combined with accurate spectral and light output characteristics, can reduce or eliminate these two disadvantages.

Although the UV curing ink is not subject to the VOC emission regulations, the curing process is related to the disappearance of ozone, so there are still environmental problems. In addition, because inkjet printing requires low-viscosity inks, the monomer composition characteristics of UV-curable inks that meet this need, but also people need to be careful when handling it, because many formulas cause skin allergic reactions. Danger.

One of the latest developments in the industrial ink market is the development of water-based inks. It has the characteristics of low cost and environmental harmlessness. Whether it is dye base formulation or pigment formulation, it has always been advantageous in the desktop printing market. This type of ink is suitable for printing on porous permeable base materials, but it requires the use of expensive special substrate materials and lamination in order to obtain the best results and outdoor supportability. Due to the special water, the water-based ink requires a relatively long drying time on the substrate, but there is a tendency for the ink to dry in the nozzle of the print head. Therefore, the nozzle needs frequent maintenance, and the printer needs to be used when not in use. Sprinklers cover.

Looking ahead, cationic systems will be widely used in food packaging, as well as water-based UV curing systems. The latter will provide a lower ink film weight, as well as a higher proportion of high molecular weight and low irritation oligomers, thereby improving health and safety characteristics. These inks will also be more suitable for use on porous and semiporous porous substrates, with better cure and less odor.

Obviously, various requirements are changing the ink market. Ink manufacturers are working harder to develop more advanced and safer products, while at the same time continuously improving product quality and improving performance to meet the needs. The digital printing industry is constantly advancing, and the ever-changing digital devices increasingly require new and enhanced ink media. The development of printing equipment and printing ink is dependent on each other. With the advancement of technology, we can be sure that in the near future, there will be better and more interesting new products.

Reprinted from: Ink Information