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Irrespective of whatever challenges are thrown its way, offset still has the ability to run faster and look smarter than the rest of the pack. But is it safe, asks Sam Cole

The global market for printed folding cartons is currently estimated to be worth around €39 billion/year, the greater proportion of it printed via the offset process, which in itself accounts for approximately 25% of the worldwide €209 billion printed packaging market.

Whilst quality of reproduction, flexibility and running speed are the key components that have helped to secure offset’s dominance hitherto – especially so in the food packaging sector – the trend towards reduced run lengths has allowed digital to gain a small but significant toe-hold. It’s a challenge that has been largely countered, however, by improvements at the front-end resulting in faster makeready and changeover between jobs.

Many of the innovations on KBA presses have been developed to offer sustainable print that delivers optimum performance, scheduling flexibility and cost efficiency, says UK and Eire executive sales director Mark Nixon. “Developments in latest-generation systems have focused upon cutting B1 makeready times and enabling faster and more efficient production.

“Firstly, there is its intelligent software-based solution that supports simultaneous plate changing in less than 60 sec, regardless of the number of printing units. Flying job change is another technological development that could enable carton printers to boost their productivity. It allows plates to be changed on dormant units while the press continues to print its current job, and sequence into production of the new job without stopping and with as few as 20 waste sheets. This results in significant production gains – especially as typical runs become shorter and shorter.”

Speed and efficiency

In response to a much-vaunted digital advantage, the technology is perfect for multiple language versions, claims Nixon. “For example, on a 6-colour Rapida 106, with the process colours for the layout and images on the first four printing units, printing of the different language text can then take place on the fifth and sixth units.”

Further time saving is achieved via the CleanTronic Synchro system, which allows the blanket and impression cylinders to be washed simultaneously, thereby cutting washing times by three minutes; and the DriveTronic SIS infeed that reduces both makeready time and downtime between jobs per shifts by dispensing with setting and marking.

These levels of efficiency provide a direct environmental gain, says manroland UK sales director Adam Robotham. “As well as accelerating production speeds to on average 18,000 sheets/hour while allowing equally fast turnaround, advanced offset technology will also tick any number of sustainability boxes.

“Anything that reduces time or resource is an environmental benefit, as it saves energy and cuts back on waste. So, although direct-drive technology uses more power, it achieves makeready within a fraction of the time taken on a conventional press. Likewise, the inline colour control facility on a Roland 700 reduces waste from 300 sheets down to below 80.”

Special effects

GlaxoSmithKline has used 3D Fresnel lenses to create a series of holographic images on the outer cartons of its Aquafresh and Sensodyne oral healthcare products. Produced by Chesapeake’s Nottingham-based pharmaceutical packaging division, the cartons were printed on a Komori Lithrone S40 offset press in five colours plus both matt and gloss varnishes.

The 3D feature simulates the effect of looking at a life-like model of a tooth as well as close-up images that help to describe the benefits of using the product. The combination of the Fresnel lens and positional control achieved through its lamination allows the process to register the inks to the lenses to create a unique brand identity. The resulting perspective produces the impression of depth, which gives the pack a tactile quality, further enhanced by the carton’s bevelled edge.

The net result is some highly distinctive and differentiated on-shelf impact which has generated a dramatic commercial response. As of the beginning of the year, the cartons have been launched in 29 different countries across Europe, the Middle East and Asia, becoming the top-selling toothpaste brand in Tesco stores after just one month’s exposure.

Manroland UK is anticipating an equally impressive impact once its Prindor inline coldfoiling technology is fully up and running in the domestic market early next year, when the system is fitted to a Roland 707 being installed at Leicester-based Qualvis Packaging. While the technology has established itself in a number of overseas markets, this will mark its UK debut, says Adam Robotham.

“It’s a unique effect that you get by printing CMYK on top of foil that’s already been laid down with the same accuracy as with printing with ink.

“The system’s capability to effectively ‘spot foil’ has important cost implications and could easily achieve the same result as a Metpol laminate, but 40% less expensively. The ability of designers to understand what the technology can achieve is fundamental to its onward adoption, and that’s what’s held it back hitherto.”

Already well-established in the commercial graphics sector, the independent PrintCity Alliance is extending its remit to encompass packaging by demonstrating a wide range of special effects achievable through offset via its VaPack initiative, including coldfoiling on a Roland 700 using only three colours. “We’re communicating with the brand owners, with designers and with the converters themselves; mostly via a rolling seminar programme initially in Latin America, but also in Europe as well,” says design and production manager Alex Dort.

“It’s a large potential value chain and it’ll be those people and those companies who want to explore new ways of doing things and develop further that will win out: the brand owner in terms of image and the printer in terms of production capability.”

Food safety

The only cloud on offset’s horizon is a lingering concern that resurfaced earlier in the year about the potential threat to food safety caused by migration of toxins from recycled board, and which has prompted the publication of a series of guidelines issued by trade bodies – most recently, the European Carton Manufacturers Association.

Ink manufacturers are understandably treating the issue with caution. “There are a number of potential sources of mineral oil in food packaging, including the substrate, process lubricants, printing inks, secondary corrugated packaging and even the food itself,” says Sun Chemical Europe sheetfed systems product manager Dr Bernhard Fritz. “Sun only recommends the use of low migration conventional sheetfed offset and UV curable inks and coatings for use on food packaging unless a functional or absolute barrier to migration is present. The choice of how to print sensitive packaging is defined by its design and visual appearance; the workflow at the converter and by the costs. Low migration solutions exist for all applications.” (See also Last Word, p35).

Behind the diplomacy and reassurance, however, some press manufacturers are critical of the ink manufacturers’ response.

“Basically, our customers are required to guarantee that there’s no migration happening, but they’re not being given a full understanding of exactly what it is that they’re putting on the sheet because the ink manufacturers aren’t willing to share formulation knowledge,” says Heidelberg’s head of product marketing Jürgen Grimm.

“The only process from a technical perspective where you can guarantee to a certain degree that no migration is happening is UV, provided that it’s 100% cured; if not, it can be more dangerous than a conventional ink.”

Machinery manufacturers have responded to the situation by increasing the number of drying units installed on the press. “Atypically, a packaging printer will set up for each unit to have a UV dryer: so six inter-deck dryers on a 6-colour press plus a bank of three additional UV dryers at the end,” says Adam Robotham.

“The most recommended method currently is to use UV-cured inks with a conventional emulsion coating over the top,” says Alexir Packaging’s CEO Robert Davison.

Outside the UK, however, the use of UV tends to be cyclical and inconsistent: currently out of favour in Germany, for example, and banned for food packaging applications in Switzerland.

There is a sneaking suspicion that the entire issue might have been over-egged.

“As it’s now possible to measure down to a level of less than one part per billion (hitherto it had been one part per million) it was pretty obvious that something was going to show up,” says Davison, “but if you look very carefully at the wording there is no proven link between any of these essential oils migration issues and anything that’s causing a problem to people.

“Not only are the contents invariably packed in a bag for added protection, but even if you use the finest virgin cartonboard, as soon as you put it into a corrugated box for transit there’s a further potential for migration to come through from that source.

“It’s a nightmare of a subject, and common sense within the EU hasn’t yet prevailed.”

KBA’s Rapida 106 offset press Rapida Inline coldfoiling (manroland) Manroland Sensodyne toothpaste carton produced by Chesapeake Pharmaceutical & Healthcare Sensodyne Aquafresh toothpaste carton by Chesapeake Pharmaceutical & Healthcare Aquafresh Fresh fruit carton (Alexir Packaging) Fresh fruit Convenience meals range by Alexir Packaging Convenience

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PrintCity Alliance
Sun Chemical