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Inkjet printing – evolution or revolution?

The Mike Fairley Column

It is easy to regard digital inkjet printing as a new and disruptive technology that is only recently having an impact on the label and package printing sectors. In practice, inkjet printing was being used for producing address labels as far back as the early 1970s. By the late 1970s, through the 1980s and the beginning of the 1990s, new inkjet print head and press manufacturers were fast emerging.

Many of these start-ups were spin-offs from Cambridge Consultants in the UK, with a whole cluster of inkjet companies being formed in the Cambridge area, including Xaar, Domino, Epson, Danaher (Videojet, Elmjet, Willet), Linxs and Xennia. Names that are still at the forefront of inkjet evolution (perhaps revolution?) for the label and package printing markets. 

Of these early inkjet companies, Elmjet was responsible for the development of the binary array, a curtain of droplets produced extremely fast by using hundreds of nozzles instead of just one. 

Later came ‘drop-on-demand’ inkjet, developed by Xaar, in which ink was only squirted when it was needed. Certainly, a number of these pioneer inkjet companies in the 1980s were undertaking various market research projects (some in conjunction with Labels & Labelling Consultancy) to look at the applications for the use of digital inkjet printing for printing ‘best before’ dates, barcoding, variable text, garment labels and overprinting on label applicator lines. All this is at least 30 years ago.

By the 2000s, other key inkjet developments were taking place. Labelexpo in 2002 saw the introduction of the Chromas Argio single color inkjet system. Developed by the Digital Label Alliance, it printed labels with UV inkjet at 600 DPI. Mark Andy also showed the DT 2200, a combination of 6-color inkjet and flexo printing which used the Dot.Factory Spice (Single Pass Inkjet Color Engine) with Xaar inkjet heads. Both the Argio and Spice machine were installed in a number of beta label plants. Hybrid presses were already seen as having interesting potential for label production.

New generations of higher performance inkjet presses and combination machines, such as those from EFI Jetrion, Atlantic Zeiser, Nilpeter/Caslon, Impika Solutions, SolarJet, Stork Prints, Konica Minolta, Mimaki Engineering and Xennia, all came into the label market in the period up to the end of 2009. That year also saw Durst and Domino – two of today’s inkjet market leaders – enter the UV inket label press market. By 2012 the third generation of inkjet presses with a resolution of 600-720 DPI was being widely used.

Today
Today, inkjet label and package printing technology is growing faster than any of the other print technologies. It’s getting ever closer to the running speeds of flexo presses – making hybrid presses easier to develop. Inkjet inks have improved considerably; color control and color management has been enhanced; resolution is getting steadily higher; web and print widths are getting wider; integration with ever-more sophisticated MIS, inspection and finishing requirements is taking place, and the quality and performance of the latest inkjet presses is close – if not equal to – flexo. 

To understand the change in the world of inkjet it is useful to look at the latest statistics. Since the emergence of inkjet label presses around 1,800 machines have been installed. This includes a few hundred hybrid flexo/inkjet presses. Still considerably lower than the installed base of 3,000 or so toner presses – but growing much faster. Over 90 percent of the inkjet presses currently installed use UV curing. Water-based inks make up the remainder, but may be seen to be more attractive in the growth of flexible packaging.

The industry is now seeing installations with an inkjet resolution of up to 1,200 DPI. A typical print head construction will contain the driver electronics, ink feed attachments, and at least one and usually hundreds of ink chambers leading to the inkjet nozzles themselves. These are simply holes in the nozzle plate. Each ink input channel is typically 20-50 micron. By comparison, a human hair is around 80 micron. 

In terms of operating speeds we can find inkjet label presses commonly running at 75 or 78 m/min, or even more. Web widths for inkjet label printing can be found up to 400mm. Many of the high-end inkjet presses are now currently available with CMYK + OGV + White as standard options. 

Indeed, digital inkjet white can be used to create interesting textures on plain papers, while UL-approved inkjet inks for durable label applications have also become available. Spot varnish, matt and different gloss levels are also possible, as well as inkjet cold foiling and inkjet printable metallic inks.

It also provides the possibility to use standard flexo substrates without priming and varnishing, and the ability to run variable data printing at high speed. Being a non-contact printing process enables textured materials to be printed, with the texture being maintained. 

Interesting to see in recent years has also been the capability to retrofit inkjet units to existing flexo presses to obtain low cost entry into digital printing, as well as the combining of inkjet and conventional technology into hybrid press lines. 

Inkjet advances have been over a long period of innovative change (now almost 50 years), but has it been a revolution? Probably not.

ABOUT THE AUTHOR

Mike Fairley is Labels & Labeling's strategic consultant.

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