Special Digital Printing Effects in Tile Decoration
Tile decorated with special effects are more striking, help drive increased margins, and can still be printed at productive speeds.
The introduction of digital printing for the decoration of ceramic tile has brought with it the same opportunities and challenges that inkjet has brought to other product areas. On the positive side for ceramic tile manufacturers, digital printing has eliminated pattern repeats, always a limitation on drums from a traditional press. With digital printing, pattern length is limited only by the memory of the PC workstation. This has allowed designers to create more realistic natural patterns and finishes. For example, stone tile are printed with realistic veins and imperfections.
Digital printers also have a faster setup, eliminating waste and economically allowing for much shorter runs. High-quality, fine finishes are virtually indistinguishable from natural materials. Digital inkjet printheads can work on textured surfaces because no physical contact with the tile is necessary, and the printheads can decorate right to the edge of a tile.
Unfortunately, once digital printing becomes prevalent in an industry, it also becomes a commodity. With all due respect to designers who can create extraordinary work, what differentiates your tile designs from others? If a business cannot differentiate, it will be necessary to compete on price.
This always leads producers to seek new opportunities. One that is beginning to take hold is the general trend for even greater creativity, which is only possible with greater detail, stronger colors, and the use of special effects such as gloss and adhesive, which modify the surface finish of the tile. Tile decorated with special effects are more striking and help drive increased margins. The best part is that effects can still be printed at high, productive speeds.
Fine Details and Strong Colors
Technology has reached the point where printheads can deliver greater detail combined with strong colors. This is achieved by doubling up on the rows of nozzles: double the quantity of ink at the same line speed leads to more intense colors. Concurrently, the resolution is doubled. High-resolution 720 dpi delivers fine detail that can accurately capture even the smallest features, such as rock veins and grains of sand. It enables smooth gradients in areas of low ink coverage (0-10% range), allowing replication of the subtle tones found in onyx, for example. It can also produce vibrant designs with strong colors for tile that require maximum impact.
For example, if a certain color tone requires 13 g/m2, the printhead on the left in Figure 1 can achieve that at 720 x 720 using 12 picolitre drops. To achieve the same color, a printhead that delivers 360 dpi would need to use the arrangement shown on the right, with larger drops placed on a more widely spaced grid. The 720 dpi image uses four times the number of dots, and each one is four times smaller.
Higher amounts of ink are typically required for printing effects vs. colors. If enough ink isn’t deposited, the effect will not be very visible. This is the case particularly with gloss, adhesive (glue), luster and metallic; these effects benefit from greater ink quantity. Light effects such as matte typically require 30-40 g/m2, while intense effects such as gloss and luster typically require 40-80 g/m2. The most intense effects such as adhesives and metallics benefit from 80 g/m2 or more.
High Laydown Technology can be used to print high levels of ink, even at high speeds. The same printhead can be operated in greyscale mode to achieve fine details when used with colored inks, or it can be operated in High Laydown mode to achieve high ink deposition rates when used with effects inks (see Figure 2). The technology enables special effects such as gloss, adhesive, luster and metallics, with the Xaar 2001+ printhead reaching an ink laydown of up to 120 g/m2 at 35 m/min line speed, or 170 g/m2 at 25 m/min line speed. In fact, some effects have been produced with even greater amounts, up to 250 g/m2 at that speed. Most offerings typically achieve half these laydown values at the same line speed.
Another option is to use the printhead in dual-color mode. Each printhead can then be used to deliver two different effects, each one providing up to 85 g/m2 at 25 m/min. For example, matte and gloss effects can be printed from the same printhead. To do the same with most printheads would require an extra printbar in the machine and double the number of printheads, a considerable increase in complexity and cost.
Special Effects in Production
Scientifica Tiles LLP was the first company in India to adopt the Xaar 2001+ C printhead and High Laydown Technology. Based in Morbi, India, Scientifica Tiles is a newly established, family-run business that manufactures high-quality glaze-vitrified floor tile for markets in India, South America, the Middle East and Israel.
Scientifica Tiles uses a KERAjet Master printer with Xaar 2001+ printheads to accurately replicate natural marble and stones, which are currently much in demand in the market. The manufacturer is benefiting from the printheads’ combination of 2,000 nozzles with 720 dpi resolution, which together deliver fine details, smooth gradients and strong colors. Scientifica Tiles has also used Xaar’s High Laydown Technology for special effects such as gloss, adhesive, luster and metallics.
“The printheads can reproduce the subtle color gradients of marble and stones, making it ideal for these designs,” says Hiren Vadaviya, director of Scientifica Tiles. “The print quality we are getting is extremely high, and we have been very impressed. A vast difference can be seen between the color gradation of the marble and granite tiles we have produced with the Xaar 2001+ and that of tiles we have seen elsewhere.”
Inol Group in China previously struggled to differentiate its tile from those of other manufacturers. However, using an inkjet printer with Xaar 2001+ printheads, this is no longer the case. Lighter-colored tile, such as jade designs, now stand out, while the boost in print quality has enabled the company to make more complex designs. In addition, Inol has found that designs with a significant use of black, which require very high ink laydown, are easily produced.
The upgrade to the Xaar 2001+ has allowed Inol to expand its product range while producing a significant improvement in cost efficiency. In addition, a stronger emphasis on creativity has enabled the business to serve the market with higher quality products and helped to enhance its brand image, reinforcing its status in China as a leading tile manufacturer.
“The new printhead has helped us achieve true product differentiation by allowing us to create more unique and innovative designs,” says Wo Wai Hao, deputy general manager of Inol.
Change is inevitable. While a major watershed moment occurred when digital inkjet was introduced as a new ceramic tile decorating technology, improvements will continue to be developed. As the technology for printing colored inks has become mainstream, tile manufacturers are looking to incorporate special effects such as gloss, adhesive, luster and metallic into their products. These provide the tile manufacturer with an opportunity to differentiate itself from others, offering greater creativity and higher profit margins as well.