As an important member of the eco-friendly ink family, UV inks are occupying the digital inkjet printing market step by step, thanks to their attractive advantages such as fast drying speed and low VOC (volatile organic compound).
UV technology development
UV curing technology has been used in the printing industry for more than 20 years. The key advantage of this technology is the absence of solvents, which reduces VOCs. Its working principle is: UV ink is selectively absorbed by UV light, and its curing is affected by the total energy of the UV light source radiating light and the distribution of light energy of different wavelengths. Under the irradiation of UV light, the photopolymerization initiator in the UV ink absorbs photons of a certain wavelength and is excited to an excited state to form radicals or ions. Then, a polymer such as a polymerizable prepolymer and a photosensitive monomer is brought into an excited state by energy transfer between molecules, and a charge transfer complex is produced. These complexes are continuously crosslinked and eventually cured into a film. Because it avoids the environmental impact of traditional solvent inks, it is considered a "green technology." Another advantage of UV technology is that it can reduce production costs, mainly in terms of improving production efficiency, saving energy, and reducing solvent recovery costs. Based on these excellent properties, the application of UV technology in the ink field has made considerable progress. According to statistics, from 1999 to 2004, the growth rate of U.S. UV ink applications was 25% to 50%. Among them, flexographic printing inks accounted for 32%; offset inks accounted for 50%; screen printing inks accounted for 25%. It is expected that the use of UV inks in these three printing markets will continue to grow.
The development of the inkjet market
Since the 1950s, the United States ABDick company successfully developed inkjet printing, inkjet printing market has developed rapidly, has become the printing technology in the corner. At present, the digital inkjet market in some developed countries is quite mature; in China, although the digital printing market has not yet been fully standardized, there is still no standard industry standard concerning product quality, but it is when the market is developing rapidly.
Inkjet printing is generally divided into continuous printing and on-demand printing in two ways. It is directly connected with the computer to solve the needs of high-speed, small-batch printing and on-demand printing, because it is a non-contact printing method, can be in the three-dimensional Printing on the object, this is actually its greatest merit. Moreover, most of the equipment for inkjet printing is provided for office work and household occupation. In the future, it is estimated that in addition to expanding in these areas, the printing sector will also grow accordingly.
The potential of inkjet printing technology is endless and it has a very broad market prospect. According to a survey report by ITStrategy, screen printing currently accounts for approximately 50% of the entire POP market. Digital inkjet printing and flexo printing almost equally divide the rest of the market. However, by 2008, the market demand for large-format inkjet print will double compared to 2003. In 2003, about 1.1 billion square feet of material was used for inkjet printing, and by 2008, this demand is expected to increase to $3.3 billion. The corresponding sales value of the market is expected to increase from 2.03 billion U.S. dollars in 2003 to 5.13 billion U.S. dollars in 2008. Obviously, digital inkjet printing technology will show its edge in the flourishing printing industry.
UV ink application
With the emergence and development of UV technology, printers have tried to bring UV technology to the gate of digital ink jet printing. However, due to the constrained ink viscosity of the continuous squeegee (IJ) nozzle, the application of UV ink jet technology has been limited. The restrictions apply only to the label, cable and wire printing industry. Until the advent of drop-on-demand (DOD, also known as intermittent ink jet) nozzles, the scope of the ink viscosity needs to be expanded, providing great convenience for the development of UV inks. For a time, many manufacturers of inkjet heads, including Spectra, Xaar, HKIS, IJT, Brother, Canon, Konica, Seiko, Trident, Sharp, etc., have developed such nozzles that can be applied to higher viscosity inks, and some even It is possible to eject ink with a viscosity of up to 100 cps at room temperature. Since then, UV inks have begun to appear in the inkjet printing market.
The emergence of on-demand inkjet heads has expanded the range of materials for UV inks. Many ink manufacturers have focused on this opportunity to vigorously research and develop UV inks. They have been successfully applied to the printing of flexible materials and rigid materials. Subsequently, digital inkjet equipment manufacturers have also developed wide-format flatbed ink jet printers that can use UV-jet ink. With the advent of this equipment, the demand index of UV inks has been rising in a straight line in recent years. In the United States, the market share of UV inks in all ink products has increased from 25% in 1999 to 2004. 30%.
There is no doubt that UV technology will become a key factor in wide-format digital printing.
Since UV printing can be printed on rigid materials as well as on flexible materials, print resolution up to 600 dpi, production efficiency in excess of 1,000 square feet per hour, durable printed images, ability to print unprocessed substrates, and price Many leading advantages, such as lower, make it have a good application prospects. Numerous screen printers have begun to use this technology to seize new market opportunities for short-run printing and apply it to the growing number of personalized, regional advertising prints. At the same time, commercial photo agencies and commercial printers have begun to purchase UV printers to compete with screen printers in the field of short-run printing.
UV ink advantage
The ideal UV-jet ink can make the printed image waterproof, anti-fade and other characteristics, its advantages over other types of inkjet ink include: low VOC; low energy requirements; instantaneous drying; suitable for a variety of substrates; before curing Will not dry; does not block the nozzle; does not need to clean the nozzle; ink composition is stable; printing quality is high (lightfastness, rub resistance); no pollution.
One of the most worth mentioning is the instant curing characteristics, which make the UV ink from the nozzle after the ejection of no ingredients into the surface of the substrate, and no contact with the substrate, so do not worry about the ink will penetrate the substrate and thus the surface of the substrate Performance affects.
The biggest advantage of UV inks for inkjet devices is that they do not cure at the nozzles. This eliminates the need to clean the nozzles to remove insoluble components. From an industrial point of view, due to the shortened maintenance time of inkjet equipment, inkjet printing using UV inks can achieve greater production efficiency.