It seems that those of us in the personalization business are always looking for the “next BIG thing” in our industry. Years ago, lasers were the “next BIG thing,” then inkjet sublimation made a huge impact on the industry. So what’s next? What magical innovation will come along that, once again, will revolutionize the personalization industry? Could it be UV printers? Truth is, it just might be, and here’s why. |
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UV inkjet printing is different from conventional solvent inkjet printing. Instead of having solvents in the ink that evaporate into the air and absorb into the substrate, UV inks are exposed to UV lights that are built into the printer which quickly cure the ink to turn it from a liquid to a solid. This technology has several advantages, including eliminating environmental and workplace health issues, the ability to print on a wide variety of substrates, high print speeds and a wide range of printing applications ranging from outdoor signage to golf balls. |
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Printing on clear or dark backgrounds can be quite a challenge for most processes and with some, such as sublimation, it’s almost impossible. UV printing is also more forgiving than other methods when it comes to the type of substrates that it works with. Sublimation, for example, nearly always requires a special polyester-coated substrate to work at all. UV printing, on the other hand, can be used to print on a wide variety of substrates of all colors, textures, shapes and sizes. But, just like other processes, it doesn’t work on everything. In fact, there are many substrates that UV inks will not adhere to without first applying a bonding or adhesion agent. Some printers can actually spray an adhesion agent on the substrate through the printer nozzles while with other printers, you need to hand apply it. Either way, there is no guarantee the ink will bond until it is tested. Adhesion then, in my opinion, becomes the biggest problem in the UV world since every printer manufacturer offers their own inks and adhesion additives, and each is different. This means it is ultimately important that you test both the inks and the printer to make sure they will work on the substrates you want to print prior to making any kind of buying decision or promises to customers. Along with having to learn about adhesion with UV inks, it is also important that a potential buyer learn about the various properties of the inks. Some companies offer multiple inks to be considered but most try to offer a “one size fits all” recipe that may or may not work for you. At one time, I presumed that an ink cured with UV light would then be UV safe and thus I printed a job for exterior use. Unfortunately, I was wrong and the signs faded into nothingness within months. Lesson learned? Well, some printer manufacturers claim their inks are UV safe and although I would certainly not doubt their word, it would make me cautious—once burned and all that. One of the most popular features of UV printers recently has been the introduction of cylindrical devices for printing items like water bottles. I believe that cylindrical devices are offered as an option for every printer with enough throat to accommodate one. This brings at least two questions into the light: One, how user-friendly is the software for setting up a cylindrical job and, two, do I need another specialized ink? Although metal water bottles can be successfully printed with most UV inks, there is a different story with plastic bottles that can be squeezed. These require a flexible ink, so some of the printer manufacturers now offer an ink that stretches up to 200 percent. |
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The flexible ink option opens up other applications, such as printing banners. Magnetic signs are another possibility and some manufacturers have built their printers so there are no paramagnetic (steel) parts that would interfere with printing a magnetic material. With the multitude of inks available, a major decision you need to make is choosing the best ink for your applications. Inks can’t easily be changed so once an ink is selected you are pretty much stuck with it for the duration. Ink changes are possible if you thoroughly clean the printer, but this can be time-consuming and is not recommended for job-to-job use. Inks are usually specific to the manufacturer, and so are the print heads and rails (the bars the heads and UV light run on). Some companies manufacture their own print heads and rails, while many others use assemblies from other inkjet manufacturers, such as Ricoh and Epson. Depending on the print head, the printer may be capable of varying the size of the ink dot from as little as a couple of picoliters to as much as 20 picoliters. By varying the dot size, the printers are better able to manipulate ink density, which results in sharper images and colors that smoothly change from one shade to another. Variable-dot printing is controlled by firmware from within the printer and its software. All UV printers come with some kind of RIP (Raster Image Processor) software to drive and control these firmware options. Usually, the RIP software is developed by the manufacturer for a specific printer and has various functions, such as translating images from your computer into raster images for the printer and enhancing color consistency. Although you may not be able to talk and understand RIPs in any great detail, you can see the results in the printed image, such as vivid reds, bright white and the ability to smoothly transition from one color to another. When you are considering purchasing a printer, it’s very important to look closely, compare results and ask questions when you see something that doesn’t look right. If it doesn’t look right at the demo, it won’t look right when you get it home! So where is the money in UV printers? What kinds of products produce enough return to make them worth the $20,000 to $80,000 or more investment attached to these devices? It couldn’t possibly be the ability to make one-up products as is the case with sublimation. Clearly, UV is for the bulk production shop. Although 1,000 water bottles could be personalized as they are printed, the true contribution of the UV printer is printing lots of products with the same imprint—what we will call production.
One new $80,000 printer reports it can print 225,000 flash drives in a 40-hour period. That’s a lot of flash drives and that’s where these printers shine. Obviously, most of us have no need to print so many flash drives in a week, but that is why there are smaller machines. The key is finding a printer that is just the right balance between what you can afford and what you can justify with demand.
Again, this is a choice you will need to make, but most users can easily do without the Lc and Lm, and just rely on the CMYK to produce a stunning image. White is, of course, the difficult color. Because white ink needs to be opaque, it is typically very thick which presents issues with clogging the print heads fairly quickly. To compensate for this, most printers include some type of circulation (agitation) system. This is very important. Some printers circulate only the white and/or clear inks while others circulate (or agitate) all the ink colors. Regardless, a word from the experienced is to print something daily with your printer if possible. These printers are made to be used often and long idle periods can bring about some painful lessons. Mimaki printers include a feature called a “nozzle recovery system” to monitor nozzles and, according to the manufacturer, automatically identify and recover clogged print heads. I have no personal experience with this feature, but it sounds like a great one.
Ink has already been mentioned but it is worthy of another note. Some companies offer only one type of ink so it is important that you understand the capabilities of that ink. Will it stretch? Will it stick to glass (even with an adhesion promotor)? Is it fade resistant for exterior use? What kind of color pallet is available? Other companies offer multiple inks that deal with each of these issues but, as mentioned, you can’t just swap inks whenever you want to.
Finally, and perhaps most important of all, is service and support. I have already mentioned that these printers require some tender loving care. They can be somewhat finicky and they definitely require ongoing maintenance. This means your ability to contact someone for help when things don’t go the way they should is imperative! This isn’t something that can be placed on a chart. It has to be learned the hard way. But that doesn’t mean you can’t figure out which companies or distributors give good service and which ones don’t. Customers are usually more than happy to “spill the beans” about any company that isn’t living up to its promises. Just ask your sales representative for the phone numbers of several of their customers who are willing to be references. Quick responses to calls of help, quick shipment of repair parts and supplies and, of course, friendly, supportive service are invaluable for your UV experience to be a pleasant one. |