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Conventional and digital press trends

Bobst M1 shaft-driven press connected live to IoT network

Current developments in the flexo press sector point to a blurring of the boundaries between conventional and digital, greatly increasing the range of options open to label converters faced with shorter run lengths and the need for greater production flexibility.

Related to these developments, the last Labelexpo shows in Europe and America revealed a new drive to integrate conventional presses into Industry 4.0 workflows. This means repetitive manual operations are taken over by ‘intelligent’ servo-assisted systems, while press control systems exchange data with factory-wide management information systems (MIS).

Automated pressure setting is a good example of this trend. The technology has moved from wide web CI to narrow/mid-web presses, with Bobst leading the way with its ‘Digital Flexo’ press lines, where cameras continuously monitored the density of a patch of pixels, feeding information back to servo motors. At Labelexpo Americas 2018, automated pressure setting was seen on most major manufacturers’ high-end presses. 

Omet announced auto-pressure setting on its XFlex X6 press line, and Nilpeter demonstrated a range of ‘Clean Hand’ automation technologies on its new FA line, implemented by seven direct drives on each print head. Edale’s FL-3 press was demonstrated at the show with a full AiiR automation package which includes automated pressure setting.

At the show Bobst took flexo automation a step further with a demonstration on an M5 press of simultaneous exchange of plate cylinders followed by a ‘hands free’ makeready with automated pressure and register setting.

Looking forward, we could see other automation technologies make the transition from wide web to the narrow/mid web sector. For example RFID-equipped anilox rolls which allow the press control system to check the correct tooling has been fitted and aid automated inventory management.

Another key Industry 4.0 concept is ‘Big Data’, analyzed and implemented by artificial intelligence systems. The first area we are seeing this become reality is on-press inspection.

Press cameras linked into cloud-based data networks will learn about common print problems and help operators spot them before they happen and either auto-correct press parameters or alert operators to the probable cause.

Data exchange 
The final piece in the automation jigsaw will be two-way data exchange between flexo press and MIS. Up to now press control systems have been based on proprietary operating systems, requiring information to be double keyed from the MIS into the press console – for example material type and run length. 

This is now starting to change. MPS demonstrated its Talk To Me open interface at the Labelexpo Automation Arena, allowing two-way communication with a Cerm MIS. Bobst demonstrated integration of both its high-end M5 and entry-level, shaft-driven M1 presses into a browser-based Internet of Things (IoT) network, where a number of productivity and bench-marking apps are available. 

On the digital side, HP continues to develop its PrintOS cloud-based operating system, which now includes a suite of benchmarking and workflow tools including Site Flow for Labels and Packaging, OEE (Overall Equipment Efficiency) monitoring and EPM Analyzer. PrintOS is open to compatible third party applications, and it was notable that just across the aisle at Labelexpo Americas AB Graphic was demonstrating a cloud-based OEE app which monitors its finishing equipment and ties into the Cerm MIS.

Xeikon is developing its own suite of bespoke apps – the aXelerate services program – and at Labelexpo Americas added an OEE component which automatically collects data from presses and peripheral equipment and shows current productivity status.

An end to operator skills? 
Do these developments mean that skilled flexo operators will no longer be needed? Absolutely not. Automated systems will get 98 percent of the way towards an in-specification job set-up, but operator skill will always be required to make those final makeready adjustments before ramping the press to full speed and producing sellable labels. 

The key phrase in Industry 4.0 is ‘cyber assisted’. The skilled operator is helped by the intelligent machine to achieve an optimum result. Once the job is running to specification, the intelligent machine monitors itself using sensors to measure and adjust registration, print pressure, web tension, UV lamp power (measured at the web surface), while cameras and sensors check for developing print faults and measure density and color throughout the run. Once the correct number of in-specification labels have been printed, the press can even ramp down automatically – a system already implemented on digital presses. 

So the role of the skilled operator changes. They can now monitor multiple machines from a smart mobile interface from any point in the print plant, accessing a wide range of production status information in real time. This frees up time to concentrate on other value-added activities such as assembling the elements for the next job change. 

Converting developments 
Automation on the print and web transport sections is being matched by more efficient tooling systems at the converting end of the press. We are now seeing the deployment of semi-rotary die-cut systems able to operate at full press speeds of up to 150m/min. The key advantage of semi-rotary is that the same magnetic cylinder is used for every repeat size, and with semi-automatic die loading and ejection on units such as ABG’s Fast Track, there is minimal downtime between jobs. Mark Andy’s system allows the die module to be switched between semi- and full rotary operation depending on run length.

Nilpeter is currently developing the semi-rotary die station seen for the first time on its Panorama hybrid press at Labelexpo for the new FA series press. Omet has its own take on the die-cutting format issue. The company’s MonoTwin Cut system uses differential pacing between two fixed diameter cylinders to achieve the same result.

The increasing efficiency of highly automated flexo presses married to fixed-palette printing – which eliminates the need for washups between jobs – has seen flexo start to encroach on the shorter run territory of digital. This blurring of lines has only increased with the dawn of the age of the hybrid press.

Hybrid comes of age 
With digital printing taking an increasing share of the new press market from the early years of the 21st century, manufacturers of conventional presses felt the need to develop their own digital offering while not throwing away the expertise gained over many years of designing high-specification flexo presses. 

The route chosen was to ally with UV inkjet press manufacturers and incorporate their print engines into existing flexo press lines. As the chemistries of flexo and digital UV inks are similar, digital has slotted easily into the in-line format of the narrow web industry. 

This is not a new phenomenon of course. Nilpeter launched its Caslon program in 2012 with FFEI as its inkjet integration partner. But the first generation of single-pass inkjet systems were not really up to the job of matching flexo in terms of print quality or speed. 

Today, print resolutions have increased up to 1,200 DPI and speeds have reached as high as 100m/min, though a more typical speed range is 50-75m/min. Printing white generally entails a reduction in speed to allow the ink to properly whet. 

These are certainly speeds and resolutions capable of fully complementing the flexo process, while the scalability of inkjet allows it to handle standard web widths of 13in/330mm. The opacity of today’s UV white inks certainly matches flexo whites and in some cases approaches screen. 

Surveying hybrid press sales, it is interesting to note the wide range of configurations – indeed, we can say that there is no standard configuration for a hybrid press. Most presses in the field are equipped with a flexo unit before the digital engine, either for priming the substrate or to put down a first white, and 1-2 flexo units after the digital, allowing a spot color and/or varnishing. 

But some converters are ordering configurations which more closely resemble a full scale conventional press with up to eight flexo units and a digital engine inserted in the middle. In these cases the press can be used either as a digital press – bypassing the flexo print units – or as a digital press for shorter run jobs, as well as any combination in between.

Given the higher costs of UV inkjet inks, hybrid printing holds out the possibility to print far longer runs than is economic with digital-only presses. With an appropriate color management system, the dominant color in an image can printed with a UV flexo spot ink, while the digital engine handles variable print and complementary color elements. Similarly, using a flexo applied first down white is more economical than using a digital White on longer runs. The development of faster semi-rotary die-cutting units which we noted above also helps the efficiency of hybrid presses on both longer and short runs. 

Flexo with digital capability 
Another way to achieve hybrid capabilities on a flexo press is to rail mount a full web width mono or full color module. 

Labelexpo Americas saw a range of mono retrofit units such as the Graphium Printbar. This uses Xaar’s latest 1003 heads specified for either fine detail or heavier coatings and capable of operation at a maximum speed of 246ft/min (although high opacity white runs at 40m/min).

Domino showed its established K600i mono unit, while Mark Andy demonstrated its latest Digital Screen Plus model on the new P7E press. FujiFilm introduced the Samba 42000 Printbar at Labelexpo Europe in 2017, imaging at 1,200 DPI at speeds up to 90m/min. 

Web-wide mono retrofit modules have a range of possible applications. They can act as a ‘digital black plate’ providing a variable data capability; can apply a first down white; or act as a variable imaging spot color station. Properly specified inkjet heads capable of handling higher viscosity functional coatings without clogging allow converters to apply variably imaged spot matte or gloss coatings. Jetting UV-curable adhesive will also allow variable cold foiling, replacing the static flexo coating plate.

Inkjet embellishment units can simulate 3D-type tactile effects such as embossing and debossing, although full-specification Braille is not yet possible on single pass systems. A press can now be designed to digitally print, create raised image areas, digitally cold foil and follow the design with spot matt or gloss varnish, all without any plates and with variable imaging possible at each point.

In Chicago we even saw the addition of mono retrofit modules to a hybrid press, demonstrated by Edale and its US partner FujiFilm on the Graphium X hybrid press. At the show Gallus announced that its Digital Embellishment Unit, now undergoing beta testing as part of the Gallus LabelFire hybrid press, could be made available as a module on an ECS or Labelmaster flexo press at some point. 

Digital presses 
The debate about whether off-line or in-line finishing is more efficient continues in the digital press market. From recent Labelexpo shows we see a clear trend for digital press manufacturers to offer in-line operation as an option. Examples include the HP Indigo GEM inkjet embellishment unit, seen in-line with a 6900 press at Labelexpo Americas, and now also incorporating digital cold foiling. 

Xeikon has long been an advocate of in-line processing and at Labelexpo Americas demonstrated both in-line laser in the Automation Arena and an all-in-one entry level print and converting system called Label Discovery combining a Xeikon 3000 press and entryCoat finisher – which can also be used as a near line finisher. Colordyne’s compact 2800 Series Mini Laser Pro launched at Labelexpo Americas includes full color print, lamination and laser die-cutting in one line. 

Konica Minolta demonstrated its AccurioLabel 190 dry-toner electrophotographic digital press at Labelexpo with a near-line GM finishing unit, but is also looking at options for fully integrated finishing.

Special requirements
With half of all PS label volume in industrial labels, mostly using variable print, digital press suppliers have pushed hard the robustness of their print processes for harsh environment applications.

HP Indigo showed at Labelexpo Americas its Pack Ready for Labels program, using a new primer which gives added robustness to labels printed on the 6900 press. Flint announced at the show UL certification, in partnership with Flexcon, for the Panther UV inkjet technology which drives its PX press series.

Another area of active development for UV inkjet is low migration. This has taken a major R&D effort since LM formulations require larger particle sizes and it is critical these do not clog the fine jetting nozzles. An example is Screen’s Truepress Jet L350UVLM press seen at Labelexpo Americas, which uses the company’s LM inkset combined with nitrogen inerting to flush oxygen from the curing chamber.

Water-based developments
Not all inkjet developments have involved UV. Memjet has made strides in water-based technology for its OEM partners resulting in a new pigment-based aqueous ink system called Duralink.

The technology was first run out with a Chinese OEM partner, but Colordyne also announced plans at Labelexpo Americas for a second-generation 3600 Series AQ retrofit module using Duralink technology to be rolled out in the second half of 2019. 

(Colordyne is not abandoning development of its UV retrofit systems. At the show it also announced a partnership with UV ink developer Kao Collins to offer bespoke formulations to users of the 3600 Series UV-Retrofit unit which will increase printhead life, improve durability and give a wider color gamut).

Konica Minolta has partnered with Memjet and at Labelexpo displayed equipment developed by the two companies which Konica Minolta will sell to label converters. The Precision Label Series 475i – shown with the matching PKG-675L laminator – uses Memjet technology to produce finished corrugated materials, including folding cartons, displays and traditional cardboard boxes. It allows short-run, customized and personalized packaging production for label converters looking to diversify. 

Epson has its own take on aqueous technology with its popular L-4033AW, now superseded by the L-4533AW, which was launched at Labelexpo Americas. The show machine included a beta version of an in-line spectrophotometer and a robotic automated head cleaning system. Currently, spectrophotometric calibration is carried out off-line. The new system will allow fully closed loop color management. 

New players 
A significant trend is the addition of new players to the digital label press sector. Wide web CI specialist Uteco has made a major foray into the narrow web market in partnership with ebeam Technologies and INX Digital, demonstrating the modular Gaia electron beam inkjet printer. The press offers food compliant short run print capability for the food and pharma markets and prints on a wide range of substrates including aluminum, paper and films at speeds up to 320ft/min. It can be configured up to 36 inches wide. 

Uteco has also collaborated with Kodak to bring to market the 650mm-wide Sapphire Evo digital press for labels and flexible packaging. The press uses water-based inks to print on films and paper at speeds up to 900ft/min. 

Another key wide web player, Bobst, has stepped into the narrow digital web arena through its acquisition of Mouvent. Mouvent’s key technology is the 3D-printed ‘Cluster’ which brings together imaging units, ink supply and alignment systems, and provide the basis for a wide range of possible system configurations including sheet-fed (under development) and web-fed press systems for applications ranging from textiles to labels and folding cartons. 

Its label-specific machines are the L701 (170mm-wide) and 702 presses (340mm) using either UV or water-based inks and available in six colors plus white. Mouvent is now working with Bobst on developing in-line finishing. These presses will soon be joined by the LB705 for flexible packaging. 

And 2018 saw another major player from the commercial print digital sector launch a dedicated label system, as Canon entered the market with its Océ LabelStream 4000 series 5-color UV inkjet press (CMYK+W) with a print speed of 48m/min. The press is available in print widths of 330mm (13in) or 410mm (16in) with an optional performance mode of 68m/min for less demanding print jobs. The press uses Xaar 2001 UV inkjet printheads, with a resolution of 720 x 600 DPI. 

Suppliers from outside Europe and the US are also starting to make an impact. Chinese company Shenzen Handway has launched the LabStar330 drop-on-demand digital press with a print speed of 100m/min and resolution of 1,200 x 1,200 DPI. The press is available in 4-7 colors including optional white and spot color. Print width is up to 50mm (13.7in). The company is currently exploring hybrid options. Another Chinese supplier, Spande – long-time agency for Pantec – is launching a sophisticated hybrid press with automated print pressure setting in partnership with Domino.

Although we have long predicted the impending consolidation of the digital print sector, it seems that hybrid is opening up a range of niche options for new suppliers, suggesting the vibrancy of this fast developing sector still has some way to run.

ABOUT THE AUTHOR

Andy Thomas is strategic director of Labels & Labeling.

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