Xaar\'s 70mm-wide 180dpi printhead, the XJ500, jets two million drops of ink per second.
Inkjet printing is key to many packaging solutions. Greg Lockett provides an insight into the intricacies of leading developer Xaar’s printhead production Despite all the technological advances today, we are still unable to purchase a car that will run on a variety of different fuels. The fate of our car engines still relies on us choosing the right fuel at the pumps and we all face the consequences if, by mistake, we fill our cars up with the wrong fuel. Yet, this is just the sort of demand that is being made of digital inkjet technology, with printers expecting printheads to be able to accept a whole range of different ink types. However, with precise research and pioneering production techniques involving a combination of high-tech electronics and chemistry, Xaar plc has developed a manufacturing process to produce piezo-electric drop on demand inkjet printheads which use a variety of ink types with definitive success.
For Xaar, innovative concepts, specialist research and controlled conditions are key to the production of its printhead technology, involving processes that are extremely far-reaching and exceptionally precise. Manufacture and production is not just about simply gluing and piecing together a variety of electronic components, it’s about successfully merging highly divergent technologies to achieve an optimum result – a versatile, working inkjet printhead that is capable of producing millions of droplets of ink per second (for instance, Xaar’s 70mm-wide 180dpi printhead, the XJ500, jets two million drops of ink per second).
There are two scientific disciplines that are applied during printhead production – physics and chemistry. By encouraging electronics to operate in conjunction with inks you are faced with a difficult integration process which lacks practicality but which produces an astounding print effect. Managing and integrating these highly divergent processes is extremely challenging and is something that Xaar has honed to a high level of precision and reliability on a mass production scale, manufacturing over two million printheads to-date.
The manufacturing process involved in printhead production is extremely complex. In fact, the generic build stage is so extreme that it needs to be carried out within highly controlled "clean" environments.
These "clean rooms" ensure that the wafer-thin ink channels, which are finer than human hair, and the print nozzles through which the ink is ejected are not contaminated by minute dust particles or other affected matter. If a mere pinprick of dust was to interfere with the printheads’ assembly process this could be enough to deem it inoperable and it is for that reason a strict environment is required where all materials can be handled unaffected.
Xaar has explored many filtration systems to filter the particles that pose a threat to its clean room environment, but has encountered the same problem – the filter sizes. Systems currently on the market have been designed for the medical and aeronautical industry which you would expect would be sufficient for the printing industry. Yet the filters supplied to these markets are just not powerful enough. The medical sector, for example, is not overly worried about the size of particles passing through the air as long as they’re kept sterile. And sterile is very different to clean. To overcome this problem, Xaar has designed its own special filtration system which maintains the clean environment that is required for the manufacture of its printheads.Although production of the printheads may take place in exceptionally "clean" surroundings, the ink development work carried out in the research and development stages of the printheads’ life is undertaken in ink laboratories which are by no means "clean". Here, chemical procedures and testing are undertaken to determine whether or not a printhead can easily channel ink through its electronic mechanism, which is key to determining the products’ success. A variety of inks including solvent-based, UV and oil-based are pumped through the minute ink channels to achieve the desired print effect.
Xaar’s printheads are all designed to use a variety of ink types and this versatility is one of the qualities that make them an extremely popular choice in the marketplace. For example, the XJ500 printhead uses oil-based ink in the "Ultramark 2000" coding and marking device from US company Fas-Co Coders, UV curable ink in New Systems’s "Newprint" industrial PCB printing device and solvent-based ink in the Scitex XLjet, a graphic arts printer which is manufactured by Scitex Vision. All versions of the printhead undergo the same manufacturing process but the software of each type is set up slightly differently to accommodate specific inks types for specific applications.
Meticulous care is vital during production and assembly, but once in the market, the printheads must withstand the rigours of factory production environments. Take for example the Kerajet printer, built by Kerajet and distributed by Ferro, which uses XJ500 printheads and has to withstand the extremes of the ceramic tile printing industry. Not only do these printheads have to be capable of accepting inks with a high metallergic content, they also have to maintain 24 hour print production in a very dusty environment, which is a far cry from the carefully controlled "clean" surroundings from where these printheads first started life.
Given the product design complexities and careful patenting of each printhead design, few companies have been able to achieve what would seemingly appear to be a simple print component. Such was the situation when a global branded printer manufacturer failed to produce a working printhead, despite its attempts to painstakingly breakdown and rebuild one of Xaar’s printheads. These difficulties, encountered in producing such products, accentuate the need for a controlled quality programme to ensure that quality checks are undertaken during each stage of the printhead production and testing process.
The recent achievement by Xaar’s Swedish manufacturing facility of ISO9001:2000 accreditation underlines the importance of combining precise manufacturing processes with carefully controlled quality procedures. Evaluating its quality procedures by addressing its manufacturing and production processes has enabled Xaar to ensure supply meets demand, while at the same time making sure that the quality of the output is not compromised. In doing so, it has witnessed a 700 per cent increase in the monthly production rate of its sought-after XJ500 printhead over the past 12 months.
It is easy to overlook the complexity of the new innovations and technologies that are required in order to maintain the printing industry’s position as being at the forefront of technological development. This is now a high-tech industry, where sophisticated electronic components are integral in our press designs and are expected to deliver outstanding performance and print quality. By successfully combining electronic and chemical processes, digital inkjet technology offers one of the most exciting and versatile print solutions, capable of handling a range of different applications. If the printing industry is capable of successfully delivering such sophisticated yet versatile products, perhaps the concept of the multi-fuelled car isn’t so far away.
