White paper related to HD Flexo from Esko expert 6th Feb., 2011

Flexo 2.0 Efficient, High Quality Packaging EskoArtwork white paper David Harris, Product Manager December, 2010 Table of Contents Flexo 2.0 Efficient, High Quality Packaging......................................................................................................... 1 1    Introduction ....................................................................................................................................................... 4 2    Removing the limitations on imagery ............................................................................................................... 4 3    Removing the limitations on color .................................................................................................................... 5 4    Running the gamut – doing more with less ...................................................................................................... 6 5    Consistency in print and color .......................................................................................................................... 7 6    Efficiency drives sustainability and reduces time to market ............................................................................ 7 3 1 Introduction Brand packaging production today has its challenges but also opportunities. Trends in the market are towards more product variations and also to produce the packaging regionally closer to the point of use. This naturally leads to shorter print runs – so converters, printers and all those in the production chain seek ways to become more efficient. Time to market must be reduced, while delivering packaging with the increased shelf impact that the customers, brand owners, desire. At the same time, all stakeholders are looking for improvements in sustainability by cutting out waste and adopting processes with a reduced environmental footprint. Flexography has a major role to play in this story. Coming to prominence only in the second half of the 20th century, the flexo process was originally used only for simple line work. Flexo has long been seen as the poor relation of other printing methods such as gravure and offset, with limitations on its quality and consistency. Many improvements have been made to flexo during the last few years, in all aspects such as printing presses, plates, inks and imaging technology. In this paper we will focus on one of these: “HD Flexo” technology from EskoArtwork. “Flexo 2.0” is changing expectations, allowing strides in flexo quality and efficiency. It becomes possible for flexo to displace other printing methods, leading to benefits for the printer and his customer. 2    Removing the limitations on imagery Flexo printing uses a polymer plate with the image formed in relief, in other words, using elements raised above the surface of the plate. Because imagery is formed out of many small elements (screening dots), there have always been limitations on how finely the images can be printed, both in smoothness and the range of tones possible. HD Flexo contains an enhancement to the plate imaging hardware, allowing 3 times as many image elements (known as “pixels”) than before; this is combined with a new technique for image dot construction (“screening”). The result of these enhancements is that imagery can be printed more smoothly (using a higher “screen ruling”) and with a wider tonal range – the lightest and darkest aspects of the image can be clearly shown. More technical background on these aspects of HD Flexo is explained in the earlier white papers “Resolution does matter” and “Quality on qualified plates”. The result is that image quality is equal or better than other industry standard print processes such as gravure and offset. This also allows printers and their customers to select the most efficient print process for the job, without the need to compromise quality. Flexo 2.0: Efficient, High Quality Packaging – December 2010    4 3    Removing the limitations on color Another limitation of flexo in the past was on the density and saturation of color that could be applied to the print. Consider the printing of an area such as a logo or brand design that should appear in a bright recognizable color. The printing ink is transferred to the package by the flexo plate, but during printing the ink has a tendency so “self organize”, i.e. not to spread smoothly on the print surface but instead to form small clusters. When the print is seen under a magnifying glass a distinctive pattern can be seen, which is known as “pinholing” or “reticulation”. Typical pinhole pattern The overall effect of this pattern is to render an inferior quality of image and to reduce the density of color – leading to colors that are not as bright and saturated. To solve this, HD Flexo includes a technique known as “microcell screening”. Small cells (microcells) are applied to the plate surface that counteract this behavior of the ink, with the result that a smoother print is obtained having no pinholing. The resulting color is clearly brighter and more saturated. This improvement to color has been very important in raising the quality of flexo so that it can match gravure printing. In flexible packaging it is often necessary to make a white “underprint” as a background to the design. In many cases today, the printer has to apply the white ink twice (using more plates and print stations) in order to achieve an opaque white without pinholing. The improvement made by HD Flexo means that in many cases the white can be printed just once, giving a smooth opaque result. Flexo 2.0: Efficient, High Quality Packaging – December 2010    5 4    Running the gamut – doing more with less HD Flexo has a wider color gamut with more Pantone colors Standard printing, known as “process color” is usually made with a combination of four inks – Cyan, Magenta, Yellow and Black (CMYK). All colors on the print are then made out of combinations of these, controlled by the imaging areas on the printing plate. The range of colors that are possible is known as the “gamut”; a larger gamut on the print simply means that more colors are available. As well as the inks used, gamut is also influenced by the flexo plate and the way that it is imaged. When a color must be printed that is outside of the normal gamut, the usual solution is to add an extra ink to the print, formulated to match the color. This is known as a special color or spot color. This solution is effective, but its implications are that the extra ink has to be mixed and stored, and a printing station on the press must be prepared for it. As different print jobs will use different colors, preparing the press for the new ink results in lost time on press and is a less efficient approach for short print runs. HD Flexo increases the gamut while using the same inks. This is caused by two factors. First, the increased density means that more saturated colors are possible. The gamut will now include a range of richer, brighter colors that were not printable before. The second factor relates to accuracy of color matching. The package often contains specific brand colors that will be made from combinations of the process CMYK inks – the right combination is needed to accurately match the color. Because HD Flexo provides a full tonal range, a much wider range of combinations are possible. Analysis of color measurements (profiles) has shown that while the typical gamut of flexo printing would include around 55% to 65% of the Pantone colors, an HD Flexo setup on the same inks can include up to 80% of the colors. The accuracy delivered by the expanded tonal range was found to be a much bigger factor than simply having more print density. It is possible by adding additional process inks to expand this gamut still further, but that subject is beyond the scope of this paper. With a large gamut, printers can avoid using so many spot colors. This means that print jobs can be run without having to prepare additional ink stations on the press, or even that several jobs using different brand colors can now be combined into one print run (known as “ganging” the jobs, or “co-printing”). All of this greatly increases the efficiency of the printer as well as the overall process leading to shorter time to market. Flexo 2.0: Efficient, High Quality Packaging – December 2010    6 5    Consistency in print and color An aspect that must not be forgotten is the consistency of this whole process. Fortunately, the improvements to plate making that are part of HD Flexo result in a more stable printing plate. Imaging elements on the plate formed from three times as many pixels are more robust during the print run resulting in much less variation in color and less need to stop the press to clean the plates. For more detail on this, see “Pixels – resolution does matter”. The increased color density delivered by HD Flexo also gives the printer more latitude when operating the press. On press, the printer can apply more or less pressure (“impression”) between the printing plate and the substrate. Traditionally, a higher impression has to be used to get a good density on the print, but the extra pressure can have a detrimental effect on smaller elements of the plate causing them to suffer wear as the run progresses, which can lead to color variations. Because the HD plate naturally gives more density, the printer can choose less impression, thereby avoid this problem. Available as an option along with HD Flexo, the “Inline UV” plate exposure system can deliver even more consistency. Typically once the plate has been imaged it is developed by exposure to ultraviolet light in an exposure frame: a set of fluorescent lamp tubes (as you might find in your house). This system works and can give very good quality, but the lamp tubes are subject to natural variation in their light output which affects the plate and hence the color on print. In fact, a recent survey found that about 50% of the measured color variations on flexo prints were not related to the press at all, but simply to variability of the exposure lamps. The Inline UV option replaces the lamps by a computer controlled diode light source built into the plate making device – this is not only simpler to operate but is much more consistent. 6    Efficiency drives sustainability and reduces time to market We have seen how HD Flexo is enabling flexo to reach new levels and to challenge the historical perception around its quality and ease of use. Along with other developments in flexo in the fields of plate material, inks and presses, flexo is poised to displace other print processes that were formerly used. For example, this has already been seen by the increase in the use of flexo instead of gravure for flexible packaging print, which brings benefits in both efficiency and a reduced environmental footprint. A life cycle analysis of gravure and flexo carried out by DuPont showed that flexo has 50% of the CO2 emissions of gravure and also 50% of the energy consumption during the package printing process. These savings arise principally because a flexo press is more efficient to operate, producing less waste and using less Flexo 2.0: Efficient, High Quality Packaging – December 2010    7 energy. In the past, displacement of gravure was not feasible because of the limited quality of flexo but now that the limitation is removed print buyers are free to choose flexo when it is the optimum for the job in hand. In a project for a major coffee line, brand agency Wallace Church created the new designs for the product range taking advantage of the scope allowed by HD Flexo. Needless to say the design had to meet high and exacting quality requirements bearing in mind that the previous version was printed with gravure. Russ Napolitano of Wallace Church stated, “The flexo-based HD printing process delivers the added benefits of lower developmental and production costs found in traditional flexo printing. The process also fosters shorter print runs compared to rotogravure, allowing for smaller order quantities and reducing the risk of obsolete inventory”. The agility and increased quality of today’s flexo means that it is playing a large part in delivering packaging that is of higher quality but also more efficiently produced. This reduces time to market and contributes to an improved sustainability profile for the industry. David Harris, December 2010 EskoArtwork Kortrijksesteenweg 1095 9051 Gent Belgium Tel. +32 9 216 92 11 info.eur@esko.com EskoArtwork 8535 Gander Creek Drive Miamisburg, OH 45342 USA Tel. +1 937 454 1721 info.usa@esko.com EskoArtwork Block 750C Chai Chee Road #01-07/08 Technopark @ Chai Chee Singapore 469003 Tel. +65 6241 21 26 info.asp@esko.com EskoArtwork Rm 2704-07, Unicom International Tower, 547 Tian Mu Road West Shanghai 200070 China Tel. +86 21 6327 7799 info.china@esko.com EskoArtwork Shinjuku i-LAND Tower 7F 5-1 Nishishinjuku 6, Chome, Shinjuku-ku Tokyo, Japan 163-1307 Tel. +81 3 5909 7631 info.japan@esko.com Flexo 2.0: Efficient, High Quality Packaging – December 2010    8