19 November 2019 Digital Printing Technologies

Labels stride towards automation

Whatever the print technology, press providers are increasing levels of automation to cope with a dynamic landscape for labels, sleeves, pouches and other flexible packaging.

On the one hand there was the Bobst Master M5, the acme of flexo printing, automated from head to toe, employing digitally controlled inking unit and closed loop colour controls. On the other was the Domino N610i, linked to an ABG Digicon finishing line, running at 100m/minute with inline foiling, fast change die cutting and inline inspection.

Both have been designed with the understanding that in future production runs a label printer copes with will be shorter, that turnaround times are vanishing, that no level of waste is really acceptable, either for the printer or the client.

Either printing press would perform for the label print business able to make the investment and to keep working flowing to them. Both were stars at Labelexpo. Both represent the future of the sector.

There were other futures on show in Brussels: wider webs and pouch production; water based inkjet on the cusp of becoming viable; lower cost entry level inkjet presses and more. Despite the growth in flexible packaging opportunities, label production remains core to the show and its visitors. And demand for labels is growing.

Forecasts from Infotrends reckon on a 5% annual growth for digital label press sales to 2023 and within that for toner to continue to hold the lion’s share, despite stronger growth rates for inkjet printing. Figures from Finat indicate that in Europe this year, more converters are investing in flexo than in digital presses. And there is the highly visible third category of hybrid presses, machines which combine flexo units along with digital printing, or digital presses with flexo stations.

The definition is broad and its edges are blurred, and Labelexpo’s own research points to a population of 160 hybrid machines around the globe. Some are old flexo presses with an inkjet print bar added, some are digital presses with a flexo unit to apply an opaque white or varnish. A few are from the ground up hybrid machines.

Bobst has one machine that fits the hybrid description: the Master DM5, combining the flexo print units from the Master M5 with a Mouvent UV inkjet press section. Bobst calls it the most advanced label pressing the world. The Master M5 it describes as “the ultimate digitised flexo press”.

Federico D'Annunzio, hybrid programme manager, says: “The guideline was to achieve digital automation, to create the highest possible up time. The role of the printing press is different to what it was in the past. The past was about the skills of the operators, today the press makes the quality and it is workflow that makes the difference.”

However, not all presses are like the Master M5. Bobst uses sensors and cameras to measure register, to control plate pressure and cameras to monitor print quality. This is not the first flexo press with these features. “We were missing an important part of what we could control,” says D'Annunzio. “Colour.”

Colour quality has been down to the operator, even with the Revo fixed palette of seven colours and fixed selection of consumables to avoid the need to keep switching to spot colours. “Now we have a true closed loop system for the first time in flexo with an inline spectrophotometer.

“We needed a new printing unit design because nothing else was capable of adjustment. The aim is to provide consistency, digital control and automation. Brand owners obsess about colour. Now we can go further and give traceability because we are reading and measuring what we are printing. This can start to change the relationship between printer and brand owner. The printer can sell the data of what has been printed, the proof of quality and volumes, as well as making a profit from what is printed.”

The new printing unit will eject the plate cylinder in one direction to allow the next plate cylinder, perhaps with a different print length to roll into place and then is locked into position. Servo motors make final adjustments for register and pressure.

The inking unit holds two versions of the same colour, darker and lighter. By adjusting the amount of each in a small mixing unit ahead of the ink being piped to the plate, the closed loop system can change density of the ink film and so the final colour.

The system also eliminates the ink trays that more conventional flexo print units use. Even the most parsimonious of these will need to throw out 30g of ink with each colour change. The DigiColor unit will escape with just 2g thrown out at a wash up between jobs and colours. And the nozzle application system applying a film of ink directly to the plate means no doctor blade.

Other servo motors control settings in the finishing line, a die plate is changed with the same approach as changing a litho plate on a sheetfed press; an adjustable vacuum system is used to take off the unwanted matrix and so on. It is all about minimising down time between job changes and increasing available up time to around 80% or more says D'Annunzio. In comparison he reckons a good OEE will be 50-60% for other flexo presses. As the number of job changes increases, efficiency on a standard press drops, increasing the performance gap to the new Bobst. It is built for these fast change short runs.

Domino is approaching the same target with the N610i shown at Labelexpo. This includes a flexo unit for opaque white, varnishing, foiling, slitting and re-reeling, automating every aspect of the digital press line. “We have focused on the end to end process,” says Philip Easton. “If you print and rewind before putting it into a finishing line, you lose the benefits of digital production. What we have is a single process that prints, finishes and completes the product, checked and ready for shipping. This has further been developed to minimise waste at a job change.”

This means that instead of losing all the material in the press that has passed the print heads and is in the finishing section after the required number have been printed, perhaps causing100 metres or more to be discarded, the Domino creates just seven metres of waste. This is because once the required number of labels is printed, the unprinted web will reverse back through the press ready for the next job, while settings for finishing are adjusted on the fly. A series of festoon rollers acts as buffer while any changes are implemented. “You can be printing the next job while the first is in the finishing section thanks to the festoon unit,” says Easton.

This was put to the test at the show with a demonstration that ran through three different jobs on different materials and changes amounting to ten different Skus in less than 20 minutes with 20 second changeover between each.

The development has required close collaboration with ABG which has developed digital foiling units and varnishing for the line. It is completed with an AVT inspection system to verify that the labels on the roll are within the quality parameters set by the customer. “The more automation that you have, the less waste you create and less manpower you need,” says Easton. “We think that the future for label production is same day or next day delivery, not telling the customer he has to wait two weeks.”

In the other direction there is integration with a Cerm MIS to manage the flow of jobs in the right sequence to the press, changing schedules on the fly. The first time the line’s operator may be aware of a new job is when it appears in the queue, arriving there via a web portal, online approval and order placement and potentially payment.

There is a challenge for flexo machines in meeting this kind of turnaround simply because of the limitations around plate making. Flexo plates are not as straight­forward to produce as litho plates and certainly not as fast. Repeat jobs can stay mounted on cylinders, much as gravure cylinders are stored for labels and packaging printed in this way, though robotic storage and retrieval systems may become necessary should the cylinder library become overstocked.

Equally the speed of print, finishing and delivery, is only part of the overall creation of a new label. The design and approval process is not affected, lending on demand production and supply chain economics to repeat existing artwork rather than create new jobs.

If the converters are ready to adopt digital processes, are the brands, design agencies and marketers in the same position? Having a label turned around in short order will certainly save time, but if the overall concept to delivery time is 45 days and digital print saves just two days in the process, more can be done.

The drawn out supply chain means too that the sweet spot for digital and that for flexo are not as clear cut as in commercial printing. In labels and the wider arena of flexible packaging speed is everything.

Bobst also showed off the Mouvent LB702-WB inkjet press. This is a press developed to run water based inks and stirred huge interest as a prototype two years ago. That is even more important today with the growth of interest in sustainability. No brand can afford to ignore the environment and water based inks point to an easier way to achieve food safe packaging than the use of low migration inks on UV inkjet.

It is designed to run at 100m/minute though at first will operate at around half that speed while drying is optimised and different substrates trialled. A coating unit has been developed for the press as well as priming unit ahead of printing. “This is not a press with which to print 100 copies – it is a press for long runs,” says D'Annunzio.

There were plenty of presses around the exhibition halls developed for short runs: the were 17 Memjet partners alone spread around the Brussels exhibition centre used for Labelexpo. On top of these there were entry level machines from OKI and Epson introduced a new series of Colourworks printers for in-house supply chain printing as well as a faster version of its UV Surepress. The SP 6534 was shown with an inline finishing unit running with the PrecisionCore print head and UV inks.

Stepping up again, Konica Minolta introduced the Accuriolabel 230, its fastest press yet at 23m/min. It has become the second most popular digital label press in Europe with 450 installations, says KM citing research from Infotrends.

KM is less forthcoming about the fact that the machine is also sold by Mark Andy as the Digital One, both as a standalone roll to roll machine and as one with integrated flexo unit to print white and with inline finishing to deliver customer ready rolls of labels.

This was Konica Minolta’s third visit as an exhibitor, each time demonstrating a more powerful machine and catching the attention of more serious label converters. This time around the company collected 11 sales and doubled the number of follow up leads over the 2017 show. Mark Andy was close behind with ten sales of digital presses at the event.

“KM is selling the press into non label markets, and where they have existing relationships,” says Mark Andy’s Chandler Davis. “We are selling it in the pay for print world and this is giving people more options where people do not know what their volumes will be.”

There is a Global Graphics Fundamentals Rip which delivers a more sophisticated level of control over colour management than through Konica Minolta. “We want people to realise that high end technology does not need to be crazy expensive,” she says. “This is highly affordable.”

This press was at the head of a trend towards lower cost digital presses with a number of machines pitched as presses to run alongside flexo or high speed inkjet or even alongside HP Indigo presses, particularly the high speed Indigo 8000 series. The old Indigo 6000 generation are being used for the shorter runs where up to seven colours, perhaps including white and silver are required.

The KM machine also demonstrates that inkjet is not the answer to every application. UV inkjet struggles with food packaging, though Screen offers low migration inks with its L350 UV LED press as does Durst on its Tau machines, and it can struggle with some outdoor applications where resilience and light fastness are essential.

These attributes have helped secure Xeikon's leading position in the dry toner market, yet it is expanding, both into pouch production and other flexible packaging areas, and into inkjet.

Its PX3000 had been announced two years ago along with acquisition by Flint. It has been joined by the Panther PX2000 as an entry level version with a narrower web width. At Labelexpo 2019, its inkjet technology was promoted for healthcare and beauty markets where tactility, achieved through UV cured inkjet varnish, is desirable and beyond the reach of toner. Sometimes these effects are unwanted. UV can leave a raised image when printing on top of a layer of white ink for example. Xeikon's software will knock this back to even out the finished image only where white is not needed. It runs counter to current wisdom that the best way to achieve an opaque white is to apply a layer using a flexo unit ahead of the inkjet.

The company participated in the pouch production demonstration using its FlexFlow technology that is being used by CS Labels. Its digital line was operating next to the Bobst flexo press showing how a label machine can print flexible packaging.

HP and Screen were also talking pouches, the one showing the technology the other pointing to a very neat development at one of its customers. Screen also had a new machine to show. This is the latest version of the L350 UV LED SAI, but as the press is not yet ready to launch, it was for discussion only and presented behind a translucent screen. This will take throughput to 80m/minute, uses seven colours including blue, and has a slot for an eight colour at some point. Colour management comes courtesy of a tie up with CGS and a rewind option is present to save material, running either to a rewind to a finishing unit. First machines will ship in Q1 next year.

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