A veteran of the sign and large-format industry, Eric has 13 years of experience in the areas of printing, production, operations, and management. He is currently the Operations Manager for Signs First in Nashville, Tenn.
The hair stands up on your arms, you feel the charge building, and you brace yourself for the inevitable...ZAP!
It seems that sign shops could quite possibly be some of the most statically charged places in the world (although I am a bit biased). With many shops embracing flatbed printing capabilities, static not only inflicts physical pain, but it can also wreak havoc on your prints. This is especially true when printing on rigid plastic substrates (Sintra, corrugated plastic, styrene, etc.). However, there are many options available to help minimize printing defects due to static and improve the quality of your output.
A more permanent solution to static is to install a programmable humidifier into the shop’s central heating and cooling system. (Image courtesy of Honeywell)
The Problem of Static
To better understand the cause and solutions of static, let’s venture all the way back to elementary school science class. Every physical object is made up of atoms, which contain protons (positive charge), neutrons (neutral charge), and electrons (negative charge). Static electricity is the result of an imbalance between positive and negative charges. These charges build up on the surface of an object until they find a way to be released or discharged.
In the realm of digital printing, there is sometimes a charge imbalance between substrate and ink, causing printing defects due to attraction and repulsion. Ink particles are attracted to the charged areas of the substrate like a magnet, deflecting them from their intended path. This results in printing complications such as clogged nozzles, dust attraction, and overspray. The crisp, tight dot pattern you are trying to achieve becomes an unacceptable product, resulting in frustration, costly reprints, and delays in production. To prevent this issue, the substrate needs to be neutralized prior to printing to assure the ink stays on target, providing consistent, high-quality output.
One of the most effective ways to combat static is by controlling the humidity in your printing environment. Humidity represents the amount of water vapor present in the air. Because water is a conductor, it helps remove any excess static charges from objects. Humidity control is especially important during winter months when the air is cold and dry. For the best results, humidity levels should stay between 40 percent 60 percent. To maintain these levels, consider investing in a humidifier. Available at home improvement stores, most humidifiers are available as stand-alone floor units that require water to operate. For a more permanent and consistent solution, you can also install a humidifier to tie into your existing ductwork. By setting the humidifier to the desired level, the increased moisture in the air will reduce static buildup and improve the quality of your prints.
The Ion Wand from Staticure attaches to a flatbed printer with a grounding magnet. (Image courtesy of Staticure)
This is a double-sided ion wand. (Image courtesy of Staticure)
The Hands-On Approach
In addition to a passive solution such as humidity control, you could also take a more hands-on approach to static elimination. There are a wide variety of tools available specifically for this purpose. Ionizing wands are hand-held anti-static rods attached to bare metal via grounding magnet and static elastic cord. Passing the wand over the substrate before printing will neutralize charged areas of the material. Some models have two static eliminating bars, allowing the material to pass between, neutralizing both sides of the substrate simultaneously.
If you have an air compressor in your shop, an ionized air gun would provide a great anti-static solution. By connecting the ionized air gun to your compressor, you can neutralize your substrate while removing dust and other contaminants in one quick spray.
There are also ion gloves, sprays, wipes, and brushes available. Simply spray or wipe the charged material to eliminate static attraction. An added benefit of these products is their ability to be washed and reused without losing their static-eliminating properties.
There is also a simple household solution hidden on your laundry room shelf: standard drier sheets. Just as they remove static from your clothes, they can help eliminate static buildup on rigid plastic substrates. All of these products are particularly useful because they serve a dual purpose, helping keep substrates clean while eliminating static charges.
Wide Format Kits from Staticure are designed to work with flatbed, hybrid, roll-to-roll printers and laminators. (Image courtesy of Staticure)
If you’re looking to improve efficiency and minimize operator interactivity, consider anti-static cords such as Static String or Static Elastic. These products attach directly to the printer, requiring minimum thought and effort. By attaching Static Elastic across a flatbed printer’s belt feed mechanism, charged substrates are neutralized before entering the printer. These can also be placed where the material exits the printer to minimize painful shocks to operators.
A great source for many of these products is Staticure (www.staticure.com). Specializing in the digital printing industry, Staticure provides a full range of static control solutions for sign shops, including kits designed specifically for flatbed, hybrid, and roll-to-roll printers as well as laminators.
In response to static control issues, some flatbed manufacturers have provided more permanent solutions by integrating static eliminating technology into their printers. If your printer isn’t equipped with this technology, consider having it retrofitted with specialized static elimination bars. These bars deliver high positive and negative ion output, virtually eliminating static charges. While this solution may require a greater investment, it provides maximum effectiveness, efficiency, and productivity by putting static control on autopilot. Meech (www.meech.com) and TAKK Industries (www.takk.com) are great resources for industrial static control equipment, with products ranging from static eliminating bars to ionizing air guns.
One way to control static is to keep humidity level between 40 percent to 60 percent. You can get a good room humidifier at your local home improvement store. Most humidifiers are available as stand-alone floor units, such as this one.
An Ionizing Air Gun, such as this model from TAKK, provides static elimination by attaching to your compressor. (Image courtesy of TAKK Industries)
Static is just one of the many variables that impact the quality of digital prints. As client demands continue to evolve with advances in digital printing technology, it’s important to overcome these variables and improve product quality in order to maintain a competitive edge in today’s business climate. By investing in static-eliminating solutions, not only will your output quality improve, your shop will also become a more efficient, productive, static-free environment. Happy printing!