WELCOME TO THE INK-JET AGE
WELCOME TO THE INK-JET AGE
2006-01-09 at 10:28:00 am #13722
Welcome to the ink-jet age
the term ink jet and most people will probably think of printers.
Indeed there can be few computer owners who have not possessed one, and
although the cartridges can be rather expensive, the printers
themselves are cheap and give a high quality full colour print out.
when the engineers at HP Laboratories first developed the ink jet back
in 1979 printing was far from being their number one application for
the new technology. These engineers had visions of using the device in
applications as wide ranging as medicine and materials science, but, as
so often happens it was the marketing department that decided upon the
application, printing would yield bigger profits and take far less
So it has come about that ink jet technology is now
firmly associated in the minds of most people with printing. But the
vision that those engineers had back in 1979, of ink jets being used
for a wide range of other applications, was not forgotten.
are increasingly realising that although an ink jet is a deceptively
simple technology – an array of nozzles that moves back and forth
depositing tiny droplets of ink onto a sheet of paper – it is the fact
that those ink droplets are so precisely measured and placed which
means that the range of such a device extends far beyond merely
printing on paper.
“Inkjet technology is no longer just being
harnessed to print coloured fluid inks, but also functional fluids, for
applications such as electronic circuits, displays, fuel cells, RFID
tags, live tissue engineering and rapid manufacture.” says Rob Harvey,
business development manager of inkjet manufacturer Xaar. “Inkjet, and
Xaar’s solution enables manufacturer’s to take a ‘product’ concept,
which utilises functional fluids, and build it rapidly from prototype
to one-off manufacture through to quite large volumes, economically and
with greatly reduced development time.”
understand why this is so, we need to look at the basics of ink jet
technology. The secret of the ink jet’s versatility lies in the ability
of manufacturers to drill an array of very small nozzles, just a few
micrometers in diameter, in a silicon or composite printhead. The size
of the nozzle determines the size of the droplets that can be produced.
each nozzle in the printhead lies a small ink chamber with a connecting
channel that allows it to be filled from an ink reservoir. At the other
end of the ink chamber from the nozzle lies a piezoelectric crystal
that is connected to the ink jet control circuitry. When an electric
current bends this piezoelectric crystal it forces the liquid ink down
the nozzle at high velocity, and as it comes out of the nozzle it forms
a small droplet travelling at speed. Each droplet produced is exactly
the same size and travelling at exactly the same velocity.
jet should not therefore be though of as a printer but is a general
purpose tool for creating very small precisely measured droplets of
Over the last twenty years ink jet technology has been
greatly refined, the number of nozzles in a head has increased from
just 12 to over 3,000 in some industrial devices. Droplet sizes have
been reduced to just a couple of micrometers in diameter and the number
of droplets that can be produced per second has increased considerably.
innovators are realising is that the ink jet allows the engineer to
precisely place an exactly measured minute quantity of liquid onto a
surface. In a printer the liquid is coloured ink, but it could be
anything that comes as a liquid or is suspended within a liquid medium
- from suspensions of metal particles to living cells. Similarly in a
printer the head is simply moved from side to side and the paper
gradually inched up, however, the printhead could equally well be
mounted on a mechanism that allows a minute drop of liquid to be
precisely positioned in three dimensions.
It is the development over
the last decade of a wide range of substances that can be used as
‘inks’ in ink jet print heads, together with developments in printhead
positioning and control systems that has made possible the developments
that are now starting to come onto the market.
One of the first
applications to use the unique capabilities of ink jet technology has
been in the electronics industry where special industrial printers are
being used to print the very high density multi-layer circuit boards
that are increasingly required by the electronic equipment that we now
take for granted.
Printed circuit board
technique involves printing very fine lines in a conductive ink made
from very fine silver or copper particles onto a rigid or flexible
substrate. By using an insulating ink in another print head it is
possible for the printer to quickly and accurately lay out a printed
circuit board with conductors just a few micrometers wide.
manufacturing technique not only provides the next step in
miniaturisation – Seiko Epson of Japan recently demonstrated a 20 layer
ink jet printed board that was just 200µm thick – it also helps to
reduce the amount of pollution produced by the electronics industry.
Existing circuit board manufacturing techniques rely upon the use of
photomasks and acid etching, neither of which are required by ink jet
printers which produce circuit boards using an additive process.
have already recognised ink jet as a key, enabling technology with the
potential of becoming the deposition method of choice,” says John
Attard, a business development manager with Xaar. “Inkjet is ideal for
applications where the material to be deposited is expensive;
management of waste fluid is an issue; manufacturing simplicity, yield
and cost effectiveness is key; and where variable patterns are
required, particularly on short runs.”
big advantage of this manufacturing technique is the flexibility that
it offers manufacturers and designers. Changes to the design can be
made by simply changing the CAD file that drives the printer, with no
need to create new photomasks. This makes design and development
quicker, it makes it possible to economically produce very short runs,
even one-offs. In fact the combination of all these advantages means
that many in the electronics industry expect ink jet printed circuit
boards to be the norm by 2007.
The techniques for printing circuit
boards using ink jet printers and conductive ink are giving rise to a
whole new industry for manufacturing devices using printed electronics.
These devices include RFID tags – used for wireless identification of
everything from clothes to automotive components – as well as
pharmaceuticals and event tickets. With printed electronics such tags
can be produced on a continuous roll-to-roll basis at extremely low
cost, a technology that is being pioneered in Germany in a partnership
between BASF Future Business and Lucent Technologies’ Bell Labs.
tags are not the only product from the printed electronics industry
that is set to revolutionise the world, an even more significant
product is the flexible e-paper display. Within three years people may
well be routinely reading newspapers, magazines and books on light
weight flexible screens many of which the user will simple roll up and
slip into a pocket when not in use.
Such flexible displays are built
using advanced ink jet printers with inks made from special organic
electronic polymers. Today dozens of companies around the world are
racing to commercialise.the technology of flexible plastic screens, in
the full knowledge that such displays will probably be the key
component of the next generation of mobile electronic gadgets.
such company is Philips, which is using a four-head industrial inkjet
printer with 256 piezoelectric nozzles to print the fine arrays of
organic light emitting diodes that will be used on paper thin computer
and television screens. In Korea Samsung have already announced that
they will be in volume production of 15.5inch OLED displays by May
2006, and Epson have said that they will be launching a 40inch OLED
screen at about the same time. Other companies working in the same area
include Toppan Printing of Japan, Cambridge Display Technology of the
UK, and Universal Display Corporation of the US.
In another approach
to the construction of flexible plastic displays, HP engineers in
Bristol are using inkjets to print arrays of tiny liquid-crystal cells
onto a flexible plastic substrate, an array of electrodes printed onto
the flexible plastic turn the LCD cells on and off. The result is a
full-colour display manufactured entirely using ink jet technology that
the researchers believe could, around 2010, rival the printed page in
flexibility, lightness of weight, colour and resolution.
Organic electronic circuits
in Cambridge, Plastic Logic have just demonstrated the first
engineering samples of a flexible display that uses an organic
electronic active matrix backplane and electrophoretic frontplane. The
company expect such displays to be in commercial use in e-publication
readers by 2007. Once again the ink jet is a crucial technology in
their manufacture, industrial ink jets from Xaar and Litrex are used in
Plastic Logic’s production line to print the matrix of very small
organic electronic circuits directly onto a flexible plastic substrate.
When bonded to the flexible frontplane the result is a thin, light,
flexible display that can be viewed, like paper, from all angles and in
any type of light.
Sensors are another area where printed
electronics and the ink jet are opening up new markets. In Austria a
new factory is being built by Nanoident Organic to produce organic
photo-detectors using ink jet printers. This new generation chip
factory will use intelligent, highly efficient manufacturing
the light of these developments researchers around the world are now
asking the question – if ink jet printers can be used to create
electronic circuitry, why not do away with conventional assembly and
build complete devices using an ink jet printer? At the University of
California at Berkeley engineering professor John Canny is
experimenting with ways of doing just this using a concept he calls
flexonics. Research which could soon lead to a 3D ink jet being used to
print out complete devices, including the case, electronics, battery,
and all mechanical components such as switches and plugs.
3D ink jet printers from companies like 3D Systems, Z Corporation and
Stratasys are in fact already being used to ‘print out’ prototypes of a
wide range of manufactured products. Hundreds of companies around the
world are now using them, Motorola used one to produce prototypes of
the casing for its latest mobile phone, and Hyundai have used a 3D
printer to make prototype vehicle dashboards.
Some companies in
Europe and the US are even using them as ’3D data faxes’ to send design
prototypes between their design and marketing departments and their
Asian manufacturing facilities. “Communication is so much more
effective when you can get a physical product into a customers hands
rather than a drawing or text,” says Marina Hatsopoulos.
typical 3D printer costs about $30,000 and uses a 448-nozzle print head
to deposit a pattern of bonding glue onto a layer of powder dusted onto
an aluminium plate in microscopically thin layers, the glue bonds the
powder and forms the object, whilst the un-bonded powder acts as a
physical support for the object as it is built. By dusting and printing
layer after layer the machine slowly builds up the object using data
provided by the CAD software running on the attached computer.
the printing process has finished, which typically takes about an hour,
the supporting powder is dusted off leaving a hard finished plastic
object at an average cost of about $10. This can then be further
machined, painted, or used as a mould or pattern for casting plastic or
“Time to market is extremely important it is no good
just having a good idea it is how quickly you can get that to idea to
market otherwise somebody beats you to it, you can try ten different
designs with 3D printing allowing you to quickly get customer
reaction,” says Dr Walter Bornhost, chairman Z corporation comments.
rapid prototyping systems, as 3D printers were known when first
developed back in 1986, have advanced enormously. The rather rough
jagged products of early machines have given way to smooth surfaced
products of almost commercial quality. The machines in use today are
desktop devices that can be used in any office environment says
Motorola’s global prototyping manager Mike Jahnke. “It is so quiet and
its so simple anyone can use it.”
Today with several competing
companies fighting for market share commercial 3D printer prices are
rapidly dropping and could soon hit a level that most businesses can
afford. There are even rumours of a sub-$1000 home model.
Build living organs
the price of ink jet based 3D printers drops and the quality of the
objects produced improves, the latest generation can even produce
multicoloured objects, so the range of applications for such printers
grows. Architects are using them to build models of their designs,
geologists are using them to build models of geological structures, and
surgeons are using them to plan complex surgical operations by
producing plastic replicas of the patient’s internal organs using data
derived from 3D CAT scans. Some biomedical researchers are even using
3D printers to build living organs from an ‘ink’ of live cells.
than build small plastic models of buildings, an engineer at the
University of Southern California’s Contour Crafting Centre, Behrokh
Khoshnevis, is using a giant 3D ink jet printer to print entire
buildings straight from the electronic blueprints using an ink of quick
setting liquid concrete. The university has partnered with architects,
and construction companies to help Khoshnevis develop this concept.
This system he believes will, within a couple of years, be capable of
constructing a 200m² building in a single day, including all walls,
roof, and conduits for electricity and plumbing. This is an innovation
that could completely change the construction industry.
The ink jet
is thus rapidly becoming an important manufacturing tool from
nanotechnology to construction, and one that will be increasingly
important in an era of manufacturing flexibility and product
personalisation. It is also a tool that further increases the
productivity of manufacturers by facilitating greater automation of the
Above all, however, the ink jet is a tool
which is changing the fundamental process of manufacturing away from
the reductive process of cutting an object from a solid block or sheet
- whether this is a silicon circuit board or the cylinder block of a
car engine – to an additive process where material is added in small
quantities to build up an object. It is a change that will not only
shake the manufacturing sector to its core, but will also make
manufacturing far less polluting and far more responsive to consumer