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While Drupa is mainly targeted at the commercial print sector, there is plenty to interest the packaging printer. Demonstrations of the latest kit in the three main print processes will be foregrounded, together with plenty of interesting developments in post-press and value-added finishing.

At Drupa 2004, packaging experts predicted that at the next Drupa the flexographic process would match other packaging print processes for quality and cost-effectiveness. Four years later, it’s debatable whether that has actually happened, but Drupa will certainly be a showcase for several developments that promise to push flexo closer to pole position in the near future, taking market share from both offset and gravure.

The Flexo4All strategic alliance – 19 of flexo’s most influential suppliers and manufacturers from around the world – will promote flexo for packaging at Drupa. Its members read like a ‘who’s who’ of the packaging industry: Bobst, DuPont, EskoArtwork, Fischer & Krecke, Gallus, Sun Chemical, Uteco and Windmöller & Hölscher among others. The group, which is the latter-day incarnation of DuPont’s 20-year-old Flexo – The Alternative initiative, will seek to encourage networking within the flexo industry, connecting competence and promoting flexo as “the best technology to satisfy all printing needs”. DuPont’s EMEA marketing manager for packaging graphics, Pier Luigi Sassanelli, believes that flexo is “ideal for almost all substrates, all segments, all applications and all budgets, and more.”

Versatile flexo
There have been improvements in flexo technology over the past five years – a massive boost with the introduction of digitally imaged plates, together with parallel improvements in inks and anilox systems. It is certainly a versatile process, with the ability to print onto absorbent and non-absorbent, flexible and rigid substrates.

It is also fast, with speeds of 500 metres per minute common. Its claim to cost-effectiveness rests partly on the relatively inexpensive levels of investment compared with offset and gravure, and partly on the fact that some finishing processes can be added inline, eliminating inter-process handling costs and time. There is even the claim that flexo presses are more environmentally friendly, although this assertion is not about energy use so much as the fact the process can use water-based and solvent-free inks.

But even with all these manifest advantages, Flexo4All’s claims to supremacy may remain optimistic, given that the quality of flexo printing has traditionally come a poor second, or even third, to offset litho and gravure. Flexo print is known to suffer from fluting and ghosting due to poorly formed dots on the printing plate. The problem is that an ordinary flexo platemaking process produces dots that look like a range of mountain peaks, due to oxygen that is hard to eliminate from the polymerisation stage of the process. A peak-shaped dot does not transfer ink precisely from its top face because the peak compresses during contact with the substrate and transfers ink from the sides as well as the pointed tip – hence the ‘fluted’ effect. To combat this, most studios apply a tonal curve that effectively makes the smaller dots bigger and the bigger dots smaller. But the effect of that is to allow only a limited tonal range to be printed.

However, several initiatives are underway to combat the limitations of the flexo platemaking process. The aim is to eliminate oxygen, thereby creating a plate with a flat-topped dot that can reproduce a full range of grey levels. The three companies working on this process have taken different approaches. US trade platemaking house PRP Flexo has a proprietary process for supplying flat-top-dot plates to other flexo printers. Kodak offers a complete system encompassing Flexcel digital plate, thermal top layer, platesetter, laminator and even a workflow. UK flexible packaging film printer TCL Packaging’s proprietary Fotoflex process has focused on the screening process with additional adjustments on the press for optimum results.

UV flexo is also an established technology, particularly in the labelling sector. The process uses minimal Volatile Organic Compounds (VOCs) and gives faster makereadies, besides doing away with the need for pressroom climate control, thereby cutting energy costs. And because of brighter colours and superior scuff, fade and chemical resistance, UV flexo has also gained wide acceptance by packaging buyers. Gidue will be at Drupa to show off its UV flexo mid-width webs; likewise Carint, Edelmann, Focus Label Machinery, KPG Europe and Muller Martini all have offerings in the UV flexo area. Windmöller & Hölscher is staying on after its appearance at Interpack to show the Miraflex C press, a common-impression flexo machine with eight to 10 colour decks and printing widths from 1-1.45m.

Developments in ink (see box on page 51) are also pushing up flexo’s quality, cost-effectiveness and green credentials. Fischer & Krecke’s WetFlex will be shown: entirely without inter-deck drying, the WetFlex uses inks developed by Sun Chemical that allow wet-on-wet printing with only a single drying shot delivered last in the line by an electron beam (EB) curing unit.

Digital delights
Digital technology made its first forays into the packaging sector more than a decade ago, with the launch of HP Indigo’s first web-fed label press. The uptake of digital has since accelerated to make it the sector’s biggest growth area. Digital’s impact on the packaging sector has been partly due to its substrate flexibility – everything from light-gauge board to flexible films can be printed digitally – and for its variable data capacity, which no other print process can replicate. In the short-run arena, digital continues to take work from offset and gravure. The technology also continues, through its innovatory attributes, to create entirely new markets that simply did not exist before – such as metal can decorating in runs as short as one, exemplified by Impress’s dPrint digital system.

Digital’s original capability for only a limited-gamut colour reproduction from four-colour toners or inks initially held it back in packaging, with the sector’s demand for vivid and precisely-matched colours. But this year’s Drupa will demonstrate that this gap has been closed: HP Indigo, Xeikon, Océ and Canon now all number four-colour-plus printing among their machines’ capabilities.

Many are hailing this year’s exhibition as ‘the inkjet Drupa’, and while most of these developments will concern commercial printers, packaging printers will be particularly interested that several wide-format digital inkjet manufacturers have turned their attention to the packaging market, offering a press for the purpose. Raster Printers, of Bicester, has targeted carton printers with its new Daytona H7000UV wide-format flatbed that can print onto any rigid or flexible material at speeds up to 29m2 per hour. If packaging printers can find a use for this type of technology, other wide-format printer manufacturers may follow: there are applications in short-run carton work, model-making and variable-data packaging. Cambridge-based Tonejet also has designs on the digital packaging sector with its new wide inkjet head, which it intends for food and drink carton print.

Meanwhile, there are fringe developments of inkjet technology that are directly aimed at the packaging sector. At Drupa, Nilpeter will demonstrate Caslon, a modular digital print solution for labels and narrow web packaging using four-colour process UV inkjet technology. Caslon can be integrated into Nilpeter’s conventional flexo press lines, or can function as a stand alone roll-to-roll system. Developed jointly by Nilpeter and FFEI, Caslon uses the latest Xaar 1001 printheads. This variable drop (greyscale) printhead features Xaar’s patented Hybrid Side-Shooter platform with TF Technology designed to produce dynamically variable drop sizes needed for fine detail and readable small text and smooth tones reliably and consistently in single-pass applications. Inks manufacturer Sun Chemical is also getting involved in hardware, with its new SolarJet UV flexo label press for short runs: the press is intended for runs of up to 10,000 labels for the pharmaceutical and health and beauty sectors, and uses Xaar 760 inkjet printheads.

On the non-inkjet digital score, there are plenty of new packaging-led developments at Drupa. HP will show a new web-fed Indigo for label and packaging work, the ws6000. This big brother to the well-known ws4500 is designed mainly for high-volume customers, printing at up to 30 metres per minute. Like other HP Indigos, the ws6000 can print up to seven colours, together with a new improved white, which label and flexible packaging printers will find useful. Xeikon will also launch a new web-fed press, the 8000, capable of printing onto a wide range of substrates including flexible films and self-adhesive label stocks – this builds on the corporation’s initial foothold in the digital packaging market through the original 6000 press.

The slow but ineluctable decline in CD and DVD sales in favour of downloadable digital content is responsible for a corresponding decline in machines for printing CD/DVD packaging. Here, however, digital press manufacturers are experiencing growth in sales as runs become shorter and have less lead time: printers specialising in this area are turning their attention to digital as a cost-effective answer to a changing market demand.

An interesting fusion between workflow and digital print will be in evidence at this year’s Drupa, with front-end controllers for digital presses being shown by workflow developers: EskoArtwork’s Labels and Packaging SmartStream PrintServer has been developed especially for HP Indigo’s digital presses, and there is evidence that the web-to-print boom, riding high in commercial print, may also find some limited, customer-specific footholds in the labels and packaging sector in the next two years.

Finishing school
The post-press sector looks a little different at Drupa this year, due to the continued drive among manufacturers to keep as much finishing as possible inline to the press, thereby eliminating handling time and costs, together with floorspace and the extra capital investment in separate post-press machines. This trend has always been marked among narrow web and flexo press manufacturers, and this year’s Drupa backs up the point with new launches from Gallus among others, which link die-cutting units inline for integrated production.

Sheetfed litho press manufacturers could be said to have taken a leaf out of the flexo press manufacturers’ book: Komori is one of several press manufacturers to be launching a new sheetfed press with inline cold foiling, UV coating and embossing at Drupa. Like all inline processes, the added-value units on the Komori machine slow it down by about 15-20%, but that still makes the processes much cheaper than offline equivalents. Other sheetfed packaging presses that aim to incorporate processes inline include Heidelberg’s new super-size 145 and 162cm presses, MAN Roland’s new size 7, 7b and 8 presses, and KBA.

The theme of automated, integrated production is continued into standalone post-press machinery. Heidelberg will launch a new folder-gluer, the Diana X 115: not only is the line capable of processing 200,000 cartons per hour, it also boasts a new auto-feed and a delivery packer. Die-cutting is also moving towards integrated production, with a raft of machines newly extended to incorporate functions such as embossing and foil-blocking in a single pass – these include Heidelberg’s Varimatrix 105CSF die-cutter with foiling and embossing and Blumer’s Atlas label cutters, which will be hitched inline to a label press. Chinese manufacturer Masterwork will launch a new ‘hybrid finishing line’ – effectively a die-cut, foil and stripping line – while Saroglia will show an integrated die-cutter, foiler and embosser. Ehret Control will show a label finishing line for die-cutting or strip cutting.

There also appears to be a continued trend towards short- and ultra-short-run cutting at Drupa. EskoArtwork will show Kongsberg XP digital cutters, while Saroglia will also show a new laser cutter for packaging applications.

Elsewhere in post-press, technology developments focus on minimising makereadies and the reduction of waste. Bobst, famously taciturn about its exhibition launches before any show opens its doors, has said that it will launch a new generation of its Power Register technology – a dynamic registration control software that uses photocell technology to reduce unplanned stops due to misregistration of the die to the sheet.

Also of interest is Japanese sheetfed press manufacturer Shinohara’s Casting Curing Unit (also known as C2): this offline UV coater flash-cures a varnish by projecting UV light through a patterned film to achieve a subtly imaged effect on the varnish, for decorative or security applications.

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SCREEN
Packagers’ choice

The depth of ink the screen process can lay down makes it a good choice for specialist packaging print applications – heavy metallic solids on alcohol and cosmetics packaging, for instance. Labels, too, continue to be pre-screen-printed with solid colours laid down by a rotary screen unit at the beginning of a hybrid-process narrow web press.

Specialist applications, such as Braille overprinting, have traditionally been a niche area for the screen process. Screen is also a popular choice for opaque print onto films, including stretch sleeves, which are printed by rotary screen presses and then stretched around their containers.

Screen is not limited to printing on flat surfaces – cylindrical screen print machines have been popular, especially in the drum and tank container sector, for the past 30 years – but these machines cannot resolve fine register work and must often be hand-loaded and unloaded, which contributes to high operating costs.

Screen’s ability to lay down a heavy ink film explains why it is finding a new lease of life in RFID work: it remains the only process capable of printing in a single pass the heavy film weight of conductive inks required by high- and ultra-high-frequency RFID antennae, on films, board or paper.

There are also signs that screen is the print technology of choice for applications of textured inks: working with special meshes and new formulations of inks, screen units on narrow web presses can produce tactile effects that are becoming popular in food packaging in particular.

But the quality of the screen process can be limited: four-colour process screen printing cannot resolve a fine screen ruling, and the registration between colours remains an issue. And for large-format flatbed machines, speed is limited – an average 2x1m bed machine might typically produce 500 to 800 sheets per hour in a single colour, which keeps the price of screen printing relatively high.

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INKS
Electron beam curing set to steal the show

Ink developments in the packaging industry continue thick and fast, with several ink manufacturers coming to Drupa to show developments that lend themselves to pack security and attractiveness, and offer environmental benefits. PrintCity in particular will show a four-way alliance between paper, ink, press and security graphics with a demonstration of security printing in food packaging.

The drive towards greener printing is responsible in part for the latest developments in so-called ‘energy friendly’ inks that cure faster, and use less energy to do so. The excitement at Drupa centres on electron beam (EB) curing inks. EB inks will be demonstrated on several presses, including Fischer & Krecke’s WetFlex flexo press, and Drent Goebel’s EB-variant VSOP offset presses: the VSOP will use an EB EZCure curing unit from US company Energy Sciences to deliver more operator-friendly ink drying. Like UV, EB uses electrons to crosslink at a molecular level a combination of monomers, oligomers and other chemical compounds in the ink. Its use is not new in the packaging print sector, but previous incarnations of the technology have had a high-acceleration voltage cure that has seriously degraded some types of film, including PPs. The latest breakthrough, however, is a lower-acceleration voltage EB unit that is claimed to have “largely” overcome this problem.

Sun Chemical leads the way with its work in EB curing inks. The company’s UniQure energy curable, no-VOC, liquid flexo ink system is generating a lot of interest from flexo printers – the ability to print wet-on-wet not only keeps energy and running costs low, but also allows the press to be speeded up (Sun claims top running speeds of 350 metres per minute in trials so far). While at the moment UniQure and the WetFlex process are only available for the F&K press mentioned above, Sun is working to develop retrofit kits for other CI presses. UniQure is currently available in seven colours, adding violet, orange and green to the standard CMYK mix.

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WORKFLOW
Post-press integration

Workflow has been a significant trend within the general commercial sector of the print industry for the past decade, but it has been slower to make inroads into the packaging sector. Information analyst and researcher InfoTrends’s study on workflow last year was prefaced by president Charlie Pesko’s assertion that “every time a human touches a job, you lose money”, and the packaging industry is now beginning to acknowledge the truth of that axiom. More packaging printers are getting switched on to the benefits of greater automation in their production chain, and developers are beginning to respond to the growing demand.

At Drupa, Heidelberg will showcase the extension of its Prinect JDF-based workflow to packaging and label print. It’s a move that has not been possible before now, as Prinect has only recently enfranchised the post-press and an electronic job planning board function with JDF capabilities. The full capabilities of the Prinect system will only be unveiled at Drupa. In the meantime, packaging printers must content themselves with the knowledge that the new workflow will make costs more transparent, and that it is also modular, and can be implemented one area at a time if necessary.

EskoArtwork has long been a JDF pioneer; its workflow systems are acknowledged as among the most sophisticated in the industry, and at Drupa the company will demonstrate its newest product, an end-to-end JDF workflow put together with the aid of industry partners Lauterbach (MIS developer), MAN Roland and Bobst.

It will be interesting to note whether Heidelberg’s and EskoArtwork’s moves in extending a JDF workflow to packaging printers will be reflected in other manufacturers’ machines – will they be JDF compatible? At the moment, the majority of packaging machines are not compatible, but there are signs that this might change.