Commentary & Analysis
Drupa 2012, the Inkjet Drupa…again? Cut Sheet: Breaking the rules or being creative?
By David Zwang
Published: October 1, 2012
At Drupa there were a lot of cut sheet inkjet offerings, some either already installed, and others just shown as demonstrations in this category. While there were some hints prior to the event, there were a significant number of offset and EP press manufacturers who have begun to embrace sheetfed inkjet. They are all primarily targeted at the lucrative general commercial printing market.
In many cases, commercial printers have embraced EP or liquid toner as a way to address the time and costs associated with shorter runs as well as new variable data requirements. However, many of them have started looking for a lower cost, higher performance, more flexible solution to the EP and liquid toner products currently in the market. Most of the production inkjet offerings shown at Drupa were B2, which not only increased the throughput over current sheetfed EP and liquid toner presses, but also reduced the unburdened print cost. And some even addressed flexibility requirements by creating solutions that would meet the wide range of media requirements of a commercial printer.
What was interesting was how each decided to address the new market with product engineering in their own unique way, utilizing a mix of technologies that have roots in other types of systems. There is no doubt that using successful technology and lessons learned from other types of printing systems makes cost and time-to-market sense. What's also interesting is how differently and creatively each of them are doing that.
If we look at the various production inkjet offerings, as we have established there are three primary different print head technologies; thermal, piezo electric, and continuous. But essentially they all do the same thing; they spray drops of ink directly on the surface of the media as it passes by them. Granted, I am making it sound much simpler than it really is. First of all, imagine trying to get drops of water to an exact spot on moving media. Especially when those drops are very light, and there is an airflow created between the moving media and the printheads. And if you add the air pushed by the front edge of the sheet to that mix, you can see it is even more complex than trying to do it on a web of paper. The ink is usually water based, so you want to keep it up high on the paper surface, and it needs to dry quickly, while keeping the media flat. That is a significant challenge.
Enter Landa Nanographics with a creative solution that borrows basic technology from offset imaging, and marries it with inkjet. Landa's unique solution to address these problems is to use a modified version of offset. The Landa technology jets the water-based ink onto a continuous warmed blanket and then uses the blanket to offset the image droplets to the paper. The benefits are multiple. First of all, it allows them to run a much wider selection of papers and paper weights. Second, they actually use heat on the blanket to evaporate the water, which means that when the dots image on the paper, they sit much closer to the surface and don't wick into the paper fibers. This creates a sharper dot with more saturated color, in addition to other benefits. It also overcomes some of the issues associated with interrupted airflow caused by the paper transport.
In the case of cut sheet presses, you would think there are really only a few reliable ways to move media through a press and retain registration. However, even with that, there has been a lot of creativity in equipment design. When you look at competing sheetfed offset presses, while there are some differences in their feed and transport technology, for the most part they are very similar. Yet with the new entries into cut sheet inkjet, we see an array of very different systems. The same can be said for the actual imaging technologies.
MGI has a strong focus on specialty applications for commercial printing, so they need to support many different kinds of media. The MGI production inkjet presses use a fairly creative and unique transport system for their sheetfed presses that includes both friction and vacuum feed, depending upon the press, to support media from 135gsm to 600gsm (50 to 220lb). All of their machines have a unique media registration system that automatically senses and adjusts the media feed, including skew.
Screen offers the TP J SX press which uses a feeder and delivery very similar to that of an offset press. However, on this press the transport is more like those used in an electrophotographic press than an offset press. Screen uses a linear motor drive rotary vacuum table, with head stops and a side guide to move the sheets through the press. This transport, according to Screen, allows support for board media up to 20 pt. It offers duplex mode, in which it uses a paper-reversing unit consisting of a transfer drum and a belt drive that brings the printed sheet back to the front of the machine to be sent back through again to print the reverse side.
And then there are the types of transports you would expect. The Komori and Konica Minolta press is built on a standard offset frame transport, albeit with inkjet imaging instead of rollers. But you would expect that from Komori. Interestingly though, the Fujifilm J Press 720 also has a feed, delivery, cylinders and grippers for transport just like an offset press. If you recall, the J Press was initially shown at the 2010 Graph Expo, and had its first NA unit installed at Gilson Graphics, a commercial printer in Michigan. Again, what we saw was a modified offset transport with inkjet imaging. This transport strength enabled them to introduce a new model at drupa, the Jetpress F, which was designed to target the packaging market with 24 pt. board, and variable imaging capabilities.
As you can see, they are all very different, yet they all generally support the same weights of paper with about the same throughput.
With continuous feed, since we are moving a web of paper through a press, there are also different approaches to address the challenges associated with inkjet, but we will save that discussion for another article.
Usually when there is desire to change or update a process, the first reaction is to start from where you are and incrementally change the process. In the case of the sampling of inkjet developments I have identified here, you can see some very creative and different approaches to addressing this new emerging and exciting print process. Since production inkjet is still a comparatively new field, many of the vendors are watching the others and learning from their experiences, so it will be interesting to see how this all unfolds over time.
Now the most important piece is how you can use the same kind of creativity to take advantage of the new sheetfed inkjet technologies in your business.
Don't be afraid to break the rules, and let your creativity show…
In the next article, I will continue this production inkjet educational series by looking at KBA production inkjet technology and futures. In each subsequent article we will look at a different vendor's offerings, and how they are being used in production.