These are alternatives to conventional separate labels, decals, shrink sleeves and in-mould labels, or analogue direct printing methods such as screen, dry offset or pad printing.
This has especially big potential in the packaging sector, where we’re seeing the first serious take-up of DTS printing for drinks bottles, sleeves and cans, with the likelihood that this will soon spread to similar packaging items, such as more irregularly shaped personal care bottles and tubs.
Heidelberg, meanwhile, thinks it’s mostly balls, so far. Its ‘4D’ Jetmaster Dimension DTS robo-inkjet is already used commercially to knock out personalised footballs. The company has big ambitions to print onto all sorts of objects and expects to develop applications for retail, web-to-print and industries such as automotive and aviation in the future.
DTS can be thought of as the opposite of 3D printing. Instead of creating a shaped object by additive or subtractive manufacturing, it takes an existing shape created elsewhere and adds a surface decoration. While technologies are much more in their infancy than the over-hyped 3D (which is in reality some 30 years old), digital DTS techniques and applications are more obviously suited to serve existing printing requirements.
Jets for PETs
In August, Martens Brouwerij in Belgium installed a personalised digital bottle printing line. Called ‘Direct Print Powered by KHS’ the line has been developed by KHS, a large German filling and packaging system maker and commercialised via its NMP Systems subsidiary.
Martens uses the system to offer personalised short runs of PET beer bottles while keeping up with the standard bottle filling line: 12,000 bottles per hour. It uses Xaar 1002 GS6 printheads to jet high-resolution text and images in five colours, using food-certified low-migration LED-cured inks developed by Agfa.
An early job at Martens was a TV tie-in that saw different actors from a Belgian sitcom portrayed on the bottles. A dedicated smartphone app uses augmented reality to make the actors come to life and interact if two bottles are placed next to each other.
“Direct printing onto empty PET bottles is breakthrough technology that enables beverage companies to change graphics within minutes instead of weeks,” says Phil Johnson, managing director of NMP. “The ability to create designs and print them directly onto bottles quickly virtually ‘on-the-fly’, is a powerful marketing tool which will give brands the ability to localise, personalise and customise their products to drive highly-effective promotional campaigns. Brand owners are looking for deeper consumer engagement and digital printing will make it a reality.”
Another German bottle filling line maker, Krones, has developed a direct digital print system for empty bottles made from PET, PP or PE, also using Xaar 1002 GS6 heads and UV inks. Heidelberg was involved in the project and supplied the inkjet system, which uses aspects of its 4D technology. This is called DecoType and has a print height of 200mm. The bottles don’t have to be cylindrical: a demo video of a field test system shows it printing on oval and indented plastic bottles, such as for shampoo.
Developer talk
While most end-users and in some cases the printer developers aren’t saying much in public, component and electronics developers are far more forthcoming. For example, Industrial Inkjet (IIJ) in Cambridge is a partner of Konica Minolta’s inkjet printhead operation and develops and integrates printing systems, often for other developers.
“We do a lot of direct product decoration,” says managing director John Corrall. “It was probably about a third of our business last year. We are selling Konica Minolta heads to machine builders and also building machines ourselves. If you look at the head customer projects at the minute, a very high percentage are some kind of tube printing.
“A couple of people have announced systems. If you look at Wifag-Polytype, it’s what they call cups, but they are margarine tubs really – a vaguely square trapezoidal margarine tub with a big lip, a return on the top where the lid clamps on.”
Wifag-Polytype’s DigiCup was announced in 2013 and there have been commercial installations. It prints on round, oval and multi-sided cups at speeds of 40 to 120 cups per minute.
Tubular sells
Hinterkopf in Germany reckons it was first to market with a cylindrical object digital printer. Its D240.2 inkjet costs about €2.5m (£1.8m) depending on spec. This can print plastic tubes, aluminium tubes, aluminium cans, cartridges, bottles, cups and other containers, with 16 mounting mandrels. White ink can be used with clear materials.
In July its first machine went into Ritter, located south of Augsburg, which makes plastic products for sectors such as medical technology and road construction and landscaping. Ritter used screen and thermo transfer printing, but job changes were getting too time-consuming.
“Customers buy ever smaller quantities to be delivered in shorter periods, so that we have to offer the service of stock keeping and just-in-time deliveries,” says joint managing director Ralf Ritter. “We want to be trend-setters in the print-on-demand business of plastic cartridges.” The company has now verbally agreed to take a second machine.
IIJ helped with the head development for the Italian Martinenghi Michelangelo KX48P metal tube printer, launched at the Metpack show in Germany last year. “It’s a huge thing weighting 30 tonnes,” says Corrall. “It’s a beast but really quite sexy – it has Star Trek doors that open when you walk up to them!”
With a footprint of 4.5x5.6m the big Michelangelo can accept tubes from 13.5 to 66mm diameter and 50 to 280mm lengths. It can print in up to seven colours including white. Feeding uses linear motors.
On the ball
Heidelberg unveiled its 4D concept at at Drupa 2012 in Düsseldorf. Jason Oliver, Heidelberg’s senior vice-president of digital print solutions, describes the process as taking a 3D object and adding a fourth dimension: print. The development of the robotics and 3D shape handling has all been done in-house, he says.
Last year the company announced its first commercial 4D system, the Jetmaster Dimension. Two of which were installed by the end of 2014. These are Liechtenstein-based BVD Druck & Verlag and German Druckhaus Mainfranken, a print partner of web-to-print company Flyeralarm. Both are so far only offering online ordering of personalised footballs, with up to three lines of text. BVD’s online ball shop at www.balleristo.com offers personalised balls at around £65.
The Jetmaster Direct uses Xaar heads and initially only prints in black UV-cured ink. At next month’s InPrint show in Munich a four-colour version will be launched. Oliver says the Jetmaster Direct can be fitted with holders for other objects than balls, and next year there will be a larger system with a wider range of holders, including a flexible manipulator and a six-axis rotator.
He says that there’s no real purchase price for the Jetmaster Direct, as the company plans to supply it on a click charge model. He says Heidelberg is talking to retail organisations to install Jetmaster Directs in-store to personalise objects while customers wait. An order from a large German retailer is close to announcement, he says.
In the longer term the company envisages printing on very large three-dimensional objects, with a different robotic system. “In the future we will also be able to print large-scale advertisements on airplanes, trucks, buses, trams, etc,” says Oliver. “This will revolutionise supply chains.”
Nearly all the systems being developed for DTS are some form of inkjet. However, there are alternatives. Since 1994 Cambridge based Tonejet has been plugging away with a nozzleless electrostatic ink droplet projection system that’s particularly suited to non-porous media. The liquid pigment inks are made by Sun Chemical and INX. In theory it can print on virtually anything, although to date it’s been used for beverage cans.
Until recently the only announced commercial user has been Ball Packaging Europe in one of its German sites, which uses a Tonejet to print directly to unfilled beverage cans. However marketing manager Simon Edwards says that a second machine is being installed at US contract printer Bev Can Printers, which will use it to supply the booming craft brewing sector with relatively short runs of up to 100,000 pre-printed, unfilled cans.
Edwards is confident this will lead to other orders in the States. At least two more component sets are with integrators in Germany already, he says. “It’s about to take off,” he predicts.
Technical challenges
A big challenge for making an inkjet print onto a variable shape is that inkjets work best at a fixed, usually very short throw distance for the drops to fly before hitting the substrate. Some DTS systems try to get round this by rotating the object as much as possible to keep the gap small and constant. However, printheads are straight with linear nozzles, so some parts of a curve are closer than others. The ink droplets may do different things as they hit.
Cambridge based Global Inkjet Systems develops electronics cards and driver software for OEMs, that sit between the RIP and the head and work out when to fire droplets. It has done a lot of development work on controllers and software for DTS.
It has worked out methods to handle inkjet printing onto conical-section objects (for instance paper cups). When rotated under a printhead the wide and narrow ends move by a different distance for every degree of rotation. So the drop density and the resolution of the print varies continuously along the length.
“Normal screening doesn’t work, and you get graininess that looks horrible,’’ says managing director Nick Geddes. “Then there’s dot gain. Colour calibrating with greyscale is a nightmare. We correct for all those effects, so all that’s left is the distortion. We’ve only done it for a small number of heads so far but we can do it for any. It’s not yet perfect but you can get quite a long way towards making something look pretty good.”
Drinks bottles are basically combinations of cylinders and cones (sometimes with waists and ridges), while square tubs for margarine and the like have flat sides and conical-section corners. GIS has worked out methods for these with a combination of geometry and variable throw distances for the droplets.
Printing round corners
The ceramic tile industry has seen an amazingly rapid adoption of digital printing over just a few years, replacing screen printing. At least 60% of decorated tiles (70% to 80% by some reckoning) are now printed by inkjet, with the global industry spread across southern Europe and Turkey, Brazil, India and China.
There are about 20 digital tile printer makers worldwide. Cambridge based Xaar’s 1001 and newer 1002 inkjet print heads are used in many these, thanks to their abilities to handle the gloopy fluids and large pigment particles needed for ceramic ink. Toshiba TEC and Seiko also make ceramic-friendly heads.
Most tiles are flat, so where’s the shape connection? Well, some tiles are curved and used on edges, so the pattern needs to wrap around the curve. Projecta Engineering in Italy has developed the first tile printer to print round corners. Its EvoMoving system prints on small ceramic tiles, such as bullnose mouldings, frame mouldings, decorative pieces and step tiles. By tilting and angling the Xaar printheads, it adapts the projection angles to the tile surface and minimises the throw distance.
In the longer term, DTS may be adapted for short-run decoration of ceramic table and drinks ware, which is mainly done by transfers, pad and screen today. Straight-sided mugs and flat plate centres would be relatively easy to handle, although heavily concave and convex dishes, plates and glasses lie beyond today’s technology.
Affordable DTS
You don’t have to pay a million and find room for a giant industrial printer to get into DTS. It is possible to buy a small flatbed for a much smaller outlay.
At Drupa 2008 Mimaki announced the UJF-3042, a compact A3 format UV flatbed that would fit on a (reinforced) desktop. This started with a modest price around £22,000 (since reduced to about £17,000), high resolution and the ability to print on thick objects up to 50mm high. It can print onto golf balls, pens, phone covers and other promotional items as well as flat items. Small items are held in jigs.
Buyers queued up and since then Mimaki has refined the original design with six colours and a primer plus a 150mm object depth and an optional ‘Kebab’ accessory to rotate cylindrical bottles under the heads. It also launched the A2 UJF-6042 for £39,995 and has just announced the larger UJF-7151 with a 710x510mm bed.
Third parties have developed accessories, for instance Innovative Digital Systems in the US makes risers to increase the UJF-3042/6042 bed height to 300mm, plus jigs including larger cylinder rotators and a rotating jig to print wraparound sides for multiple phone cases. It has also developed its own Revolution 360 UV-LED inkjet for printing on single cylindrical objects up to 75 mm long/high, with 150mm optional.
Mimaki’s rivals have since launched similar machines: Roland DG with the £19,999 A3-plus VersaUV LEF-20 and more recently Mutoh with the £15,000 A3-plus ValueJet 426UV.
These printers certainly count as DTS. Personalised promo goods are booming and these devices also work with flat items such as glass, wood, Perspex, leather and card as well as industrial applications such as switch and instrument panels.
Dawning awareness
While DTS systems are still rare enough to be news when a big one goes in, awareness is growing, says Phil Jackman, product manager at inkjet ink maker SunJet. This was particularly noticeable at last year’s InPrint show in Berlin, he says. “People used to come to us at the end of a project when they thought ‘oh dear, I need some ink’. At the show we had brand owners coming to us with different products saying ‘I make these analogue, how can I do it digitally?’ It ranged from washing machines to coffee machines, flooring, car parts, catheters. It was almost boundless, the number of things people brought to the stand. A lot of the time our answer was ‘Why?’ or ‘no.’ But it led some to interesting projects.”
