Everyone knows ink jet technology is used in the personal printers we use in our homes and offices, and most know about the large format printers used to print posters, building wraps and point of sale material also based on this technology. But what about creating 3D structures? Or printing directly on to boxes with a hand-held printer? Or even printing conductive tracks and electrical components? The possibilities are endless.
With its ability to print or deposit materials without contact onto a wide range of substrates, ink jet is becoming the printing or deposition process of choice. The amount of waste is minimised, because only the material required is printed - and because the imaging is digital, the flexibility for product variation is infinite.
Back when I began working with ink jet technology over 25 years ago you had to develop all of the technology yourself. Over the last decade everything has become much easier, with an array of suppliers of printheads, inks, test equipment, software and integration services to help you. So what could be easier - find a printhead, go to an approved ink supplier, put together some pipes and mechanics and you have a new product or process!
Not surprisingly it isn’t that straightforward. We may have much more advanced components and fluids than ever before, but there are always some things you have to do for yourself, and there are plenty of potential pitfalls to prevent you succeeding. Also, you want your product or process to work better than your competitors, or to have some special features to gain competitive advantage. Therefore you probably need some customisation of the standard issue components.
Most companies looking to use ink jet technology in their new products or processes consider the printhead technology first. Certainly it is a critical component and to a large extent will determine the print speed, resolution and cost of the final system. However, the ink is perhaps more important for many new and emerging applications and should be looked at first. Those new to ink jet technology are often surprised at the constraints placed on ink jet ink formulation as materials compatibility, pigment loading and viscosity are very different from conventional analogue printing inks or pastes. To develop an ink that will be jettable and yet still retain the right functional and optical properties can be challenging.
Even if an ink matches the required printhead fluid parameters, does it actually jet properly? To see what is going on, by far the best thing to do is to watch the ink jetting from the nozzles. Then you can clearly see if the drops are being produced cleanly and flying in the right direction. But how do you see thousands of drops per second per nozzle 20 microns in diameter travelling at up to 15 metres/second? The answer is development tools that are now available for the common printheads used. These use strobe systems to freeze the view of drops in flight, high magnification cameras to capture the images and computers to analyse the images and present the data.
Printhead technology for non-office applications has improved considerably over the past few years. Some heads are adapted from desktop technology, which makes them low-cost to purchase and can reduce maintenance costs as you can afford to replace them regularly. Dedicated industrial printheads cost more, but normally have a better capability as far as jetting ink is concerned, and last longer – and the choice is wider than ever before, with new players entering the market, so it’s important to research what is available.
The process development for your chosen application is also critical. What substrate is to be used? Porous, non-porous? How will the ink or material stick to it? Will it need surface treatment, such as a pre-coat or corona? How will the ink be dried or cured? – which can be particularly challenging in roll-to-roll or high speed applications. What properties of the image or material deposited are important?
UV-curable inks are being increasingly used for industrial applications as they have the advantage of never drying out in the nozzles, yet can be controllably fixed on the substrate using a UV-lamp or LED array. Several vendors have been advancing the capabilities of UV curing recently, and again off the shelf and customised systems are available.
Once all the ink/substrate issues have been resolved, you also need to control the printhead or printheads to print the images or patterns. This requires a way of getting from a vector or bitmap image to the right pulses at the right times at the printhead. Datapaths and image control software to do this are now available off the shelf, and several vendors will customise solutions to suit your needs.
All of these components or sub-systems are available to those wishing to develop ink jet products or processes. But many companies have no experience of putting such systems together. Even if they have they may lack the resources to do the job quickly and efficiently. So this is where the ink jet integrators and system builders come in. These companies have developed many systems in the past and have the skills, know-how and technology to get a product to market or a process integrated with production within a short time.
So is that it? Well, all of these companies are willing to help you, but they are looking for customers with vision, who want to revolutionise their industry by offering something new or better than ever before. Is that you or your competitor?
You can meet key ink jet industry suppliers at the IMI Europe Ink jet Technology Showcase Conference in Zürich, Switzerland June 2-3, 2009. Full details and on-line registration at www.imieurope.com