Xaar joins the Si-MEMS printhead club

It’s been a few years since Xaar announced the development of a silicon-MEMS thin film piezo printhead to form the basis of their P4 (platform 4) product range. So has it been worth the wait? On 2 June, 2016 we got first details at the product launch and it certainly looks both impressive and competitive. Here I’ll explain why.

But first let me just explain what silicon MEMS (abbreviated to Si-MEMS) actually means and why it’s being increasingly seen as the future for piezo printheads. The use of silicon as a base for developing powerful computer chips, memory and other electronic devices has revolutionised industry and our lives. These devices are made by the diffusion and coating of materials in layers at extremely high resolutions. MEMS technology is making structures in and on silicon using similar techniques. This involves etching as well as depositing materials. Over the past decade or so etching techniques have become much better, faster and cheaper, making the mass production of MEMS devices viable. The technology is used for a very wide range of applications, and one of those is in ink jet printheads. Thermal or bubble jet heads can be considered MEMS devices in that physical processing is often required in the manufacturing process, and Memjet takes the process much further by building CMOS circuitry with the actuator structure on top.

But the other term often heard in conjunction with Si-MEMS is thin film piezo, and they go hand in hand. Si-MEMS allows a printhead manufacturer to make actuator chambers and ink passageways at a finer scale than previous techniques. The material is much stiffer too, so that the walls between chambers can be made thinner. Unfortunately as the chamber dimensions are reduced, you need to make a thinner and more flexible piezo actuator layer to flex into the chamber to displace a drop from the nozzle. Until recently ink jet devices used bulk piezo, made from wafers of the material. Thick film deposition of piezo has also been used, forming layers around 20 microns thick. For the use in Si-MEMS devices much thinner coatings are used, with piezo layers 2-5 microns thick on top of flexible diaphragm layers only half that.

For Xaar, moving to Si-MEMS offers many benefits. Perhaps the biggest one is it will finally allow them to work with aqueous inks which are becoming increasingly important for commercial and packaging printing, and are of course essential for textile printing. It will also operate at much higher linear speeds than possible with Xaar’s previous designs.

Xaar 5601 GS3p0 printhead
The new printhead consists of 4 chips mounted in a Z-shaped module. Each module can print over roughly a 4.5 inch (115 mm) width at 1,200 dpi and at 120 metres per minute. Alternately the printhead can be supplied with 2 colour inks and print at 600 dpi. Inks can be either aqueous or solvent-based and the printhead can be operated in binary or greyscale mode with drop sizes ranging from 3-21 pl.

The actuators are thin film piezo configured in roof mode, with nozzles at a pitch of 300 per inch. That equates to a pitch between nozzles of 85 microns. Each row of nozzles is offset, with each pair at 1/600th of an inch and the pairs offset by 1,200 of an inch. This allow single or 2 colour printing.

Xaar 5601Although later to the game than some of their competitors, Xaar has taken the opportunity to use the latest technology internally. For instance the connection technology used is state of the art. They have also focussed on producing a design that is easy to implement. The head has alignment features to allow easy replacement, with the final nozzle alignment taking place in software. As the head covers a wide width there are fewer ink and electrical connections reducing costs and complexity. The Z shape enables printheads to be assembled in wide arrays with stitching also taken care of by software. The heads are also reasonably narrow in width, so stacking heads together for a full colour system will be compact – Xaar claims only 200 mm for 4 colours.

The printhead has been designed with a high drop velocity – a figure of 9 metres per second was quoted at the press conference but I understand higher velocities are possible. This should allow wider spacing between printhead and substrates while maintaining print quality.

Drop placement accuracy will also be high – Ramon Borrell, CTO of Xaar, stated they were achieving 3 sigma within 5 micron at 1 mm spacing.

One of the design considerations with a high density piezo printhead is thermal management. The heat from the actuators heats the ink, and if the temperature of the ink varies then so does its viscosity and therefore the drop volume. So Xaar has incorporated its high flow rate technology which will equalise and stabilise the temperature across the printhead, and which will also keep ink fresh at the nozzles and rapidly remove bubbles by passing ink right behind the nozzles.

AcuDrp Technology
A new feature incorporated into the printhead design compensates for manufacturing variations between nozzles. It allows the printhead to be calibrated to equalise drop volume and velocity across each printhead and all of the printheads in an array. It claims to do this dynamically, so perhaps can also be used to reduce crosstalk and maximise printhead life.

Partnership with GIS
Xaar also announced a partnership with Global Inkjet Systems who will supply drive electronics and ink supply systems for the 5601. Xaar’s overall aim is to minimise the total cost of ownership by reducing development and integration costs and time to market.

Product introduction
Xaar aims to be manufacturing the printhead at the end of 2016 with the first product – a textile press – appearing mid-2017. A version capable of handling UV-curable inks is due in September this year, and some manufacturers will be adopting the printhead for 3D printing with a major vendor launch in 2017. Xaar is out-sourcing the silicon MEMS manufacturing, focussing on final module assembly and testing, so won’t be investing in expensive silicon fab facilities.

So, will the Xaar 5601 printhead family succeed? It does seem to tick all the right boxes for high quality ink jet printing at speed. In terms of linear speed and print resolution it is up there with the Fujifilm Dimatix Samba and Kyocera printheads, while being easier to integrate into a process. Landa Digital claimed 300 metres/minute with Samba printheads but like others this is achieved by doubling up the printheads, which Xaar could also do. HP is running web presses at 120 metres in ‘quality’ mode, but their claimed 2,400 nozzles per inch is actually 1,200 dpi with 2 nozzles in line to get 4 grey levels.

A modest yet significant product announcement at Drupa 2016

You expect at the Drupa trade show, currently running at Düsseldorf, a certain amount of showmanship. Demos with lots of loud music, Xerox has Ministry of Sound shows 3 times a day, and the show everyone wants to hear is of course from Benny Landa about Nanography.

imageBut tucked away at the end of Hall 8a is a prototype machine easily missed. Not just the machine but the significance of it too. The machine is the Canon Voyager, demonstrated every hour with the usual display of print samples under glass close by. Canon is not really keeping it quiet, it is a public display and they have a page advertisement for it in every issue of the Drupa Daily. But that’s pretty modest compared to others.

So what’s so special about it? Well, at Drupa 2012 Landa Digital showed their presses for the first time. Instead of ink jetting the image directly onto the substrate, they printed onto a flexible belt, dried the image, and then transferred the image to the substrate. The advantage of using intermediate transfer is that the process becomes almost substrate independent, one of the concerns of direct printing. Of course there is a major problem to be overcome, as you need the intermediate transfer surface to be non-wetting at the transfer stage, yet wetting when you jet the image.

I track all of the ink jet patent applications published, and can tell you that Canon probably has the most relating to intermediate transfer, with others with IP in this area such as Xerox, Ricoh, Seiko Epson and Fuji Xerox.

By now you should have worked out that the significance of the Canon Voyager is that it also uses liquid intermediate transfer, this time using a drum rather than a belt. It’s a B2+ press capable of 3,000 sheets per hour. New fixed array bubble jet printheads print 7 colours using pigment-based inks onto a drum covered with the intermediate transfer blanket. The image is then dried and transferred to the final substrate.

Little information has been given about Canon’s intentions for the press. It is planned for a launch in 2018 and will be aimed at high-end commercial printing applications demanding the highest print quality.

Canon already has experience of producing high quality from fixed ink jet arrays in the DreamLabo photofinishing machine, although in that case printing is directly onto coated photo paper.

So with a confident Landa Digital announcing the building of factories ready for volume production of the Nanographic presses, and now Canon also planning intermediate transfer, what will we see in 3 years time at Drupa 2019. My prediction is we will see ink jet presses, both direct and intermediate transfer, vying side by side for customers. If anyone thinks ink jet is close to the limits yet they are wrong.

Mist, missing nozzles and condensation – Challenges for high speed ink jet printing

Mike Willis, Managing Director of Pivotal Resources, explains that it’s a lot more than just printheads and inks

It’s easy to focus on inks and printheads when thinking about ink jet presses as they are essential components and go a long way to determining performance and applications. When I bump into contacts next week at Drupa 2016 we’ll be swapping notes on what printheads are being used or who’s ink. This tends to mask all the other vital sub-systems and issues that need to be optimised to achieve a reliable and stable press.

Those who know me, or who have attended the Ink Jet academy course that I jointly present with Dr Alan Hudd, know that I’ve been a great advocate of taking ink supply and nozzle maintenance seriously during the concept phase of developing a new product. They are certainly key components of desk-top products, and their careful design and optimisation can lead to reliable industrial presses too.

The use of ink jet for high-speed printing applications – commercial and packaging printing in particular – has required the development of page-wide fixed array printheads. Printing at high-speed with ten’s of thousands of nozzles leads to some other problems too, and I’m going to explore three of them in this blog.

Are you wondering how I know about these problems? They don’t get mentioned in public most of the time. Do I hang around in bars close to manufacturers R&D labs hoping to overhear discussions at the end of a hard day’s development? No, nothing that exciting. I read patent applications.

Ink misting
Printhead manufacturers and ink formulators try and optimise the jetting process between them, often not an easy partnership as they almost always work for different companies. But no matter how elegant the drop formation process might appear, using an optical drop monitoring system, there will be microscopic drop fragments created at the point where the tail of the drop breaks away from the nozzle. These very small, often sub-micron fragments of ink, have little momentum and drift with the prevailing air currents around the printhead. In high-speed printing the substrate passes underneath the printheads, drawing air along with it. The turbulence this creates distributes the ink mist throughout the rest of the machine.

Condensation
Aqueous inks are the choice for many of the new presses under development. But these require extensive dryers within the press. At very high speeds it may be necessary to heat the web before, or immediately after, printing. Driving off the water carrier can improve the print quality by preventing excessive bleed and absorption into the substrate. But it also leads to the creation of large amounts of water vapour. Just like your kitchen windows when you are cooking, this water vapour will condense on anywhere cold enough; like the printheads and mountings within the press. And as it builds up it will drip onto the substrate and ruin the beautiful printing.

Drop detection and missing/misaligned nozzle correction
When you have tens of thousands of nozzles, you have the problem that the failure of just one of them could conceivably affect the high print quality demanded by these applications. There are some great technologies for hiding any artefact caused by a missing or misaligned nozzle – for instance by increasing the dot size each side of the missing nozzle, or substituting a different colour. But you can only play these tricks if you know which nozzles are causing the problems. Technology is therefore being developed to either check the drops in flight, or the printed image, to look for these defects. Taking into account the number of nozzles involved and the print speed this is not a trivial issue to overcome.

So when you see the impressive new ink jet presses at Drupa 2016 think of the difficulties that the engineers have had to tackle. Some of problems are not very glamorous, but they all require satisfactory solutions to provide reliable systems.

Drupa 2016 – no surprises? What have the ink jet engineers been up to?

Mike Willis, Managing Director of Pivotal Resources believes this year’s show will be evolution not revolution

drupa-3

So far pretty much all of the pre-announcements of digital press technology at this year’s Drupa trade show are similar to those made in 2012. So what have the industry suppliers been doing for the past 4 years?

Back in 2012 many ‘launches’ were, in reality, technology demonstrations. There is nothing new about this; I’ve seen the same thing since the first Drupa I attended in the 1980’s. At the last show the big story was Landa Digital’s Nanography. A few print samples were shown, demonstrating potential for the process but far from saleable print quality. This year Landa is back with what should be machines close to being ready for sale.

The same goes for Xeikon, who demonstrated their liquid toner press in 2012. This year we are promised a full colour version. And there are many other examples of this: demonstration at one Drupa, commercialisation at the next.

So why does it take 4 years from showing a working prototype to having a machine ready for launch? What on earth do engineers get up to for 4 years? Well, for a start there may be many changes made to the machines over that time in response to 3 factors:

Feedback from customers
At the last Drupa, potential customers will have made comments on what they liked or didn’t like about a press. This feedback may provoke extensive revision of a machine. As an example, we know from Landa Digital that the large touch screen controls on the side of the presses were not liked, and the panel is now more conventional, and at the delivery end of the machines.

Process development
Building an ink jet press is relatively straightforward. You just source ink jet printheads and ink and most of the job is done! Well, there are still a few people who think that way, but most have learnt that the reality is very different. There are a wide range of areas requiring careful design and development, such as head mounting and alignment, nozzle maintenance, ink supply, data paths, drying or curing… the list is long. If the process involves fundamental new technology, like the Landa Nanoinks and intermediate transfer belts, they don’t develop themselves either, but require considerable work. There are many other issues that are special or critical for high-speed single pass printing too, but I’m saving that for a later blog.

Changes to the design
As demonstrations for a Drupa show come closer and closer corners are cut to get everything working. After the show a major ‘post mortem’ takes place. Are we using the best technology now? With hindsight what would we do differently? What changes should we make to meet the manufacturing cost budget? Now we are aware of the competition what changes should be made to remain competitive?

I’d like to point out that the engineers don’t get 4 straight years to do these redesigns and developments. Ideally it’s much better to get to the next Drupa having been through beta testing at selected customer sites and to have made further revisions in the light of operational experience. So allow perhaps a year for this and we are down to 3 years.

So a development engineer’s job is pretty tough. And it’s going to get worse. The next Drupa is 3 years away, not 4. So if you meet an ink jet development engineer at the upcoming Drupa be sympathetic!

Landa steals the biggest print show on earth

For the past couple of months we’ve heard snippets of information about Benny Landa’s new digital printing technology nanography. Yesterday at Drupa, the biggest printing industry show in the world, while everyone else was desperately trying to finish building their stands and get their machines working ready for today’s opening, Landa revealed his technology to the world’s press.

Standing between two large digital presses with huge touch screen interfaces for their front covers, the charismatic Benny Landa claimed “its great to be back”. “It was all meant to be a big secret and surprise” said Benny, but in March an Israeli finance company had let slip that Landa Labs was preparing to launch digital presses. Since then we’ve been told that Nanography uses aqueous ink containing nano particle pigments. Ink ejectors are used to print at high resolution.

Yesterday we learnt much more. The ink is capable of being jetted by any type of ink jet printhead, piezo or thermal, but for the moment piezo heads are used. Benny says the heads are modified to suit the ink, which we believe may mean tuning for the optimum drop volume and drop break-off and perhaps ensuring materials compatibility. The printheads print vertically downwards depositing the drops on to a moving heated transfer belt. This is kept at a surface temperature of around 120C and most of the carrier liquid water is driven off. The aim is to work towards a target life of 500,000 impressions life for the belt, which will be operator changeable.

There is provision for up to 8 printheads and hence colours. The belt is brought into contact with the paper sheets or web during its reverse pass and the image, said at this stage to be like a thermoplastic film just 500 nm thick, is totally transferred to the paper. No further fixing of the image is required, nor any post treatment or coating. Duplex printing is achieved in the sheet-fed machines by printing the front and back images successively along the belt, transferring the front image to the sheet, reversing the sheet and then making a second transfer onto the reverse side. With the web press the front and back of the web is printed side by side on the belt, and the web makes two contacts with the transfer belt with a turning bar in between.

The process is claimed to work well on any type of paper – coated or uncoated – as well as a range of common plastic films and foils making it suitable for packaging printing. Benny explained that at this stage many image defects are visible as the machines are still in development. Having learnt from previous mistakes these machines will not be shipped until everything is working and the technology reliable, which realistically means 18 months time at the earliest.

Landa Corporation will be selling presses themselves, but has also announced three partners – there are more on the way – who will use the technology within their own machines. Komori, Manroland Sheetfed and Heidelberg have been announced so far. In all cases Landa will manufacture and supply the ink and other consumables, such as the transfer belt.

Landa’s strategy is as follows. Businesses aren’t buying conventional presses like they used to – sales have dropped by 50% in the past 5 years. Although growth in pages printed digitally is huge and there’s a choice of digital presses on the market, at present only 2% of pages are printed digitally. Although digital media will take over from print in commercial markets over the next few decades, other areas like packaging will remain. So overall there is still a huge potential market for digital presses. The tough economic times, the poor outlook for print against social media and the rapid obsolescence of digital technology hold the market back. By offering the same technology from multiple vendors the fear of buying the “wrong” technology disappears, just as VCR sales took off once there was a clear winning format.

The economics of the Nanographic process will also help. There is a clear aim to match the cost of ownership and cost per page of offset presses, so there will be no need for printing companies to chase personalisation-type jobs, they can use these machines for any run length. The cost of the presses is forecast to be similar to high-end offset presses of similar throughput. Full details of the initial range of Nanographic presses can be found on the Landa web site at www.landanano.com .

Although the current presses will be aimed at commercial printing and packaging markets, Benny also expects the process will move eventually to office markets too.

So, where did the funding come from for 10 years of development? Well, it’s effectively self-funded by Benny Landa himself from the proceeds he made with his previous generation technology. Landa Corporation has four units – the Landa Fund helping economically disadvantaged youth, Landa Ventures investing in technologies of the future, Landa Labs working on energy harvesting, drug delivery and personal care, and Landa Digital Printing.

There is still plenty of work to do behind the glossy exterior of the machines. The banding visible in the image indicates there is more optimisation of the ink for the printhead and perhaps transfer belt. Over the past two decades we have seen many times in the patent literature proposals to print aqueous-based inks onto a transfer surface, drive off the water, then transfer the image to paper, but none has been commercialised. But heated belts and transfer were at the heart of Landa’s Indigo technology too, so if anyone can succeed Landa can.

Far from relaxing, Benny Landa is obviously enjoying the development of this new technology. Asked when he might consider retiring Benny immediately responded “never!” “One day someone will find me lying by the side of a machine!” Let’s hope that doesn’t come anytime soon.

Anticipating 2012, in particular Drupa

It’s that time of year when we reflect on the past year and wonder what the new year will bring.  In the area of ink jet, 2011 has brought some interesting product launches, in particular the commercialisation of the Memjet technology by Lenovo, LG, Lomond, Xante, OWN-X and others.  At the recent IMI Europe Ink Jet Conference in Lisbon, we heard that ink jet textiles are a fast-growing application, and ceramic tile printing is also rapidly gaining market share.

So what will 2012 bring?  Well most eyes are focussed on Drupa, the printing industries trade show held every 4 years in Dusseldorf, Germany.  Although many of us in the industry associate Drupa with expensive hotel rooms miles from the city and the terrible Drupa song, it really is the pinnacle of the printing industry calendar.

Ink jet is increasingly demonstrating great potential for use within the commercial print industry.  The main applications for the ink jet web presses launched so far has been books, coupons, transpromo, newspapers on demand and the like.  But ink jet ink technology is evolving and the capabilities of ink jet are being extended.  So far Fujifilm and Screen with their sheet-fed presses, and Kodak with their web press have claimed the ability to print on to paper types used for general printing in the industry.  It’s quite a challenge, as we have been seeing at Pivotal Resources from the patent applications being filed.

We can also see from patent applications that other vendors are likely to join the market for high-speed printing.  For instance Ricoh has many patents on page arrays of their own printhead technology.  At present, Ricoh subsidiary Infoprint uses engines from Screen that in turn incorporate Epson printhead technology.  Canon is another potential player in this market.  It now owns Océ who make high-speed web-feed ink jet prises using Kyocera printhead technology.  But we can see from the patent literature that Canon is developing page arrays using thermal ink jet, similar to the technology used in HP’s web presses.

But lets go back to the beginning and to Memjet.  Back in April 2011 it was announced that Delphax plans to launch a Memjet-powered ink jet press at Drupa.  The technology certainly has the potential print speed and cost structure to make a breakthrough product.  But let’s hope they haven’t forgotten all the other industry needs, in particular the ability to print onto a variety of paper types.  So far we have only seen Memjet-based products working on absorbent or coated substrates.  Is there a new ink technology coming up for Memjet?  That would make it a very interesting breakthrough for this market, but it would also really improve the capabilities of the Memjet technology in desk-top and wide format markets as well.