Xaar has announced a new Aquinox printhead capable of handling water-based fluids, which fills a major gap in the company’s portfolio and will help it expand into new markets.
The Aquinox builds heavily on Xaar’s existing technology, particularly around the 2002 series. As such it’s a bulk piezo printhead. It has four rows of 500 nozzles each, grouped together in two pairs. It has a 70.5mm print swathe, giving it 720 nozzles per inch resolution. It can be configured with one channel at 720npi or two channels at 360npi each. It has a maximum 48khz frequency, which equates to producing 100mpm at 720npi resolution. It’s possible to run it at higher speeds but with the usual trade off of lower resolution. The Aquinox is available in two versions, one with a 6pl native drop size and one with 12pl. It’s a greyscale head with up to eight grey levels. However, Xaar will write the waveforms for customers.
One of the problems in handling aqueous fluids is that water is conductive. This has been a problem for Xaar in the past where electrodes have been exposed to the ink, forcing it to redesign the internal architecture to get around this issue. Xaar has also changed some of the materials used to construct the head to optimise it for aqueous inks with high PH levels, mainly with the textile market in mind. There’s also a new drive system to optimise the drop ejection.
The Aquinox can handle a range of aqueous fluids including Acid and reactive dye, dye sublimation, dispersive and pigment inks. It’s primarily aimed at the textile market, which Xaar has missed out on up to now.
But Xaar is hoping that the Aquinox will help open up the next layer of the ceramic market, particularly finishing steps such as glazing. Graham Tweedale, Xaar’s chief operating officer notes: “We are seeing a lot of interest in people looking at differentiation and particulars more furniture related ceramics like table tops and kitchen tops.”
Xaar is also looking at the packaging market, mainly in terms of corrugated printing where speed and the ability to operate in an industrial environment is more important than resolution and 720dpi should be more than adequate.
In many ways this new printhead is an evolution of Xaar’s existing bulk piezo designs. Xaar has bought in or licensed some technology to get around particular issues though the company is coy about discussing this. Nonetheless it makes good use of a number of Xaar’s signature technologies.
This includes the ability to handle high viscosity fluids up to 100cP. This is a major differentiator for Xaar since most other comparable printheads operate at around 10-12cP. This opens up interesting possibilities for industrial printing with functional fluids. From an ink point of view, higher viscosity allows for a higher pigment loading in the ink, leading to increased colour gamut while at the same reducing the amount of ink that has to be laid down, and therefore the amount of water that subsequently has to be dried off. Tweedale points out: “That gives ink formulators a better range of tools they can work with to optimise fluids to reduce other systems, meaning less energy to dry their fluids or to have different properties to adhere to materials.”
Naturally, the Aquinox uses Xaar’s Through Flow TF recirculation. Tweedale says that some recirculation systems are better than others, adding: “We are recirculating directly behind the nozzle which enables more recirculation within the nozzle. That’s relevant to those water-based fluids that are very sensitive to humidity.”
This recirculation is combined with a very high flow rate, which results from the open structure of Xaar’s head design. This high flow is particularly useful for inks with heavier particles as it helps keep the pigment in suspension within the ink, prevents sedimentation and nozzle blockages and should lead to greater reliability.
Earlier this year Xaar introduced a new feature, SureFlow, which the Aquinox also benefits from. This is a self-cleaning mode for use in very harsh environments. The idea is that cleaning the head in situ saves a lot of time in not having to remove the head from the press. Tweedale explains: “It’s used with our waveform technology. We move the walls* quite aggressively and then the Through Flow sweeps away anything that we dislodge.”
The Aquinox also makes use of High Laydown, a technique that can deposit large quantities of fluid in a single pass and is useful for things such as a high build varnish or tactile effect.
The Aquinox also offers a very long open time – the amount of time that the nozzles can be left unused. Most inkjet printheads have a very short open time, meaning that ink can dry out and block the nozzles if it’s not being constantly jetted, so the heads have to be parked and capped to avoid this. But Xaar has left the Aquinox heads uncapped over a weekend and been able to start printing straightaway on a Monday morning without any issues. That’s an important consideration for any kind of industrial applications where the printing might be ancillary to a wider manufacturing process and the operator may not be fully focused just on the needs of the printing system.
A long open time also allows ink formulators to avoid using humectants, which in turn makes it easier to dry the ink once its landed on the substrate. That in turn means that the press will consume less energy for drying, and that there’s less danger that the drying requirements will slow down the printing speed.
In addition, the Aquinox includes all the features that we’ve seen in the rest of the ImagineX portfolio. Thus it’s built with Tuned Actuator Manufacturing or TAM2, which involves making each nozzle individually so as to deliver more uniform flat colour and tone. It includes AcuChp, which allows the heads to be tuned in increments of 9mm of print width to match each other and to give better colour uniformity across each head, as well as between multiple heads on a print bar. This in turn makes it easier to replace printheads with little additional calibration needed.
The Aquinox printhead also includes Xaar Dot, which is a greyscale technique to tune the drop in the ink to get the number of greys and also to allow a customer to run the head in a binary mode should they prefer. The head also features Xaar Guard, which protects the nozzles from physical contact and minimises build-up of ink on the nozzle plate, which in turn reduces the need for maintenance.
The Aquinox comes with a development kit that gives OEMs everything they need to get up and running. This includes the ink supply system and printhead drive electronics.
John Mills, CEO of Xaar, commented: “The Aquinox seamlessly combines all Xaar’s proven technologies and innovations into a truly transformational and reliable aqueous printhead, providing a real step change in reliable aqueous inkjet printing.” He added: “From textiles to ceramics and packaging, we see the Xaar Aquinox breaking new ground, enabling new water-based print applications, many of which were previously not possible with inkjet.”
I’ve seen the Aquinox head running at Xaar’s R&D facility in the UK. The samples that I’ve seen look very promising, with strong vibrant colours and plenty of detail. Xaar currently has Aquinox heads being tested by at least one OEM as well as several ink manufacturers. These heads should start shipping by the end of the year but it’s likely to be another year or two before we see new printers available with these heads.
Tweedale says that Xaar has extensively tested the Aquinox over the last two years to be confident that these heads should offer a lifetime of several years, noting: “There’s a big problem with highly pigmented inks in direct to garment where heads are having to be replaced in a short time cycle.” He adds: “We have looked at what problems people have and these add up to people having to replace heads quite often. So having something that has a long life span, we think we are going to be in a good competitive position from a pricing perspective.”
Finally, I think that its worth making one last point. Two years ago John Mills outlined a roadmap for Xaar. Now, plans change and technologies don’t always work as expected, and CEOs often over-sell things when talking to journalists. But looking back at Xaar’s subsequent announcements, and particularly the Aquinox, it strikes me that Xaar is pretty much bang on schedule. Tweedale concludes: “Within the next two years we will have higher resolution and higher speed printheads in the market as well.”
You can find further information on the Aquinox printheads from xaar.com.
*Xaar uses a shared wall architecture with each ink channel having two walls that can be flexed to eject the ink through the nozzle.