- THE MAGAZINE
Recently, a new technology* has been developed that enables this same printing process to be used on ceramic tile. Using an ink jet printing machine and four specially designed inks**, the technology can be used to create an unlimited number of high-quality patterns and decorations on ceramic tile, with fewer materials, less waste, and less development and production time than conventional processes.
Conventional PrintingCeramic tile is typically decorated using either screen or roller printing. With either method, the process begins by scanning the original image or tile to be duplicated into a computer, where any necessary changes are made to create the final decoration.
With screen printing, the final electronic decoration is separated into the individual colors that compose the design. These colors are then transferred to film, which is used to make each required screen. These screens are tested in the lab to ensure that they accurately produce the required design or pattern, and several modifications are often needed. Once the screen is deemed acceptable, it is then used to make production screens, and a squeegee runs across those screens to produce the decorated tile. The process is time-consuming and generates a great deal of waste, including the film, fixative, chemicals and emulsions used during the process, as well as any excess screen material.
With roller printing, each of the individual colors in the design are applied using individual rolls made of a soft polymer compound instead of screens, and any pattern used to create the design must be cut into each roll. These rolls are then lab-tested, and final rolls are created for the production process.
While roller printing provides a higher-resolution image than screen printing, it also requires more fine tuning. The rolls are typically very expensive—costing hundreds of dollars each for both lab and production rolls—so the design and testing operations must be as precise as possible to avoid expensive mistakes. Designs are difficult to change because of the time and expense involved in creating the initial design, and any mistakes made in the early stages of the process can be costly in terms of wasted materials.
With both screen and roller printing, a different glaze must be used for each color. A design that uses five different colors, for instance, requires that five different glazes be mixed, and those glazes often have to be stored in case the design needs to be reproduced later. For tile manufacturers with 10 or 12 different production lines and a broad range of tile designs, the cost of mixing and storing colored glazes can be staggering. Some companies have to store hundreds or even thousands of different glazes to manufacture their products.
Ink Jet PrintingThe new ink jet technology greatly simplifies the entire decorating process (see Figure 1). The image is scanned and modified, as with screen and roller printing, but the similarities end there. Instead of embarking on the time consuming process of making screens or modifying rolls to create the design, the electronic image is transferred almost instantaneously to the ink jet printing machine, which is already equipped with the four required inks. The design can be immediately output to one or several pieces of tile for testing. If the design is acceptable, it can be transferred to production using the same machine. If the design is not acceptable, the original digital image can be changed as needed, and additional tests can be run.
With the ink jet process, no screens, rolls or chemicals are wasted, and very little time is required to go from design to production. Additionally, since only four colors are used to create an unlimited number of patterns and designs, no mixing or storage of multiple glazes is required. The machine is self-cleaning, so no additional maintenance is needed. While production modifications are required to use the new technology, the savings in both materials and time can be significant compared to the conventional processes.
Enhanced Speed, Accuracy and FlexibilityWith conventional processes, the screen or roll has to physically come in contact with the tile to apply the decoration. The production line has to pause as the decoration is applied to each tile, limiting production speeds to around 10 meters (~32 ft) per minute. Additionally, these processes often create a “no-printing” effect, where the squeegee or roller doesn’t go all the way to the edge of the tile and a white box or line remains after the decoration is applied. Either an extra production step must be added to trim off this white space, or the white space can be left on, relegating the tile to a lower quality and therefore a lower price.
The conventional processes are also limited in terms of design flexibility. Decorating relief tile and trim pieces, for instance, is nearly impossible because the raised designs and decorations prevent the squeegee or roller from coming in contact with the entire surface of the tile. Although some modifications have been made to the roller printing process using softer, more flexible materials such as silicon, decorating relief tile with this process is still challenging and does not always produce the desired results.
Additionally, the designs and patterns created on the tile are limited by the number of inks or colors required and by the process itself. Some of today’s most popular ceramic tile designs seek to imitate natural stone, marble and other natural materials, which are inherently variable in their decoration. While such effects can be partially achieved with screen or roller printing, the process is difficult and affords only limited variability.
The new ink jet process has overcome all of these challenges. Because it is a non-contact decorating process, the tiles exit the machine as quickly as they enter, making speeds as high as 50 meters (~164 ft) per minute possible with photographic-quality reproduction.
Additionally, the decoration is applied all the way to the edge of each tile, unbounded by any mechanical limitations. And decorating relief tile is as easy as decorating flat tile. The relief design is simply entered into the computer and sent to the machine with the touch of a button. The machine adjusts itself accordingly and applies the design to compensate for the relief.
Finally, the new technology enables manufacturers to achieve an almost infinite design variability. The standard ink jet printing machine is equipped with enough memory to create a unique pattern that is 9 meters long and 36 centimeters wide—large enough to decorate about 30 12 x 12 in. tiles in a row before a design has to be repeated. The computer can be instructed to sample any tile from any point in that row and reproduce it later on. For companies that want a larger design space—to reproduce a large slab of marble, for instance—additional memory can be added to the machine. Since the new technology is based on a digital design system, the possibilities are endless—the system can be programmed to do whatever the manufacturer wants it to do.
New OpportunitiesThe new technology does require an initial investment in new equipment, and specially formulated inks must be used with the process to ensure high-quality results. But the opportunities afforded by the new technology are virtually unlimited. Ink jet printing offers a greatly reduced color palette, high versatility, ultrafine resolution, 100% edge-to-edge decoration, full relief decoration, completely random designs and computer control over the entire process.
With this new process, tile design and decoration can be easier, less time consuming and less costly, giving manufacturers the chance to increase their range of products and designs while remaining competitive—and profitable.
Editor’s NoteFerro Corp. is based in Cleveland, Ohio. The new ink jet printing technology was developed by Ferro’s Spanish subsidiary, Ferro Enamel Española, S.A. Ten machines have undergone extensive testing in production operations by various tile manufacturers in Castellon, Spain, with positive results. In July 2001, Ferro announced the beginning of its European commercialization of the ink jet printing system. The company plans to begin a phased worldwide commercialization of the new technology starting in the second or third quarter of 2002.
For More InformationFor more information about the new ink jet printing technology, contact Xavier Sanchez, Manager, Ferro Application Systems, Ferro Enamel Espanola, Ctra N340, km 61.5, 12550 Almazora, Castellon Spain; (34) 964-50-44-50; fax (34) 964-50-44-21; e-mail Sanchezx@ferro.com; or visit http://www.ferro.com.
*KERAjet, developed by Ferro Corp.
**QUICKpaint Inks, developed by Ferro Corp.