For the label printer, there is nothing shocking about static, and converters know this simple scientific phenomenon can ruin a label run. A static electric charge is created whenever two surfaces contact and separate, and at least one of the surfaces has a high resistance to electrical current. In the label converting workflow of rolls of stock becoming unwound and processed through a web, two surfaces are perpetually contacting and separating, hence, static is a constant – and something that must be kept in check.
“Think about a label printing line. Here, a massive static charge can be generated both during the printing process, and as the film or paper is unwound from a roll,” explains Matt Fyffe, vice president and general manager for Norton, OH-based Meech USA. “These charges are capable of attracting dust to the web from several feet away, and once it has deposited onto the material, it will negatively affect the final print quality,” he says.
“Static is capable of attracting considerable amounts of dirt and dust to the web’s surface. Not only will this result in a series of labels with poor print quality, it also means the label press will require frequent cleaning, thus slowing down production. A label company cannot effectively provide fast turnaround if press operators have to keep stopping machines to clean them because of the build-up of contamination attracted by static charges. Or, if labels are rejected at the inspection stage, not only is there excess wastage but also added expense,” he says, adding that static control is perhaps most critical if the end use for the label is in a medical or clean environment.
In addition to static attracting debris and resulting in label contamination, it can cause operator shocks and machine jams, says Kim West, marketing manager for Simco-Ion, Hatfield, PA, USA. “Operator safety is critical since high static charges can cause electrostatic shock to personnel, or worse, can become a fire hazard. All of these challenges affect the manufacturers’ end product, and ultimately customer satisfaction.”
With controlling static being so important for label converters, there are dedicated suppliers that manufacture a variety of equipment that take on this critical task.
“What we’ve noticed recently is that end users are demanding more sophisticated standards in the goods they purchase than they may have done a number of years ago,” Fyffe says, noting that filmic materials are being used more commonly today as they are pleasing to the eye, but at the same time they tend to generate higher static charges.
Narrow web presses used by label converters traditionally adopt tacky roller contact systems to efficiently remove contamination. “This method provides excellent cleaning and is mainly used for filmic substrates. For other substrates such as paper or board, which typically carry higher contamination levels, contact vacuum systems or non-contact systems are used,” says Fyffe.
Meech’s contact cleaning systems, the TakClean (tacky roller) and VacClean (vacuum), are employed mostly in the print and label printing sectors. Tacky roller contact cleaning systems, in particular, use elastomer rollers to remove dry, unbonded contamination from a moving web, which is then transferred onto adhesive rolls where it is trapped. The design of the system also allows operators to see the contamination being collected on the adhesive roll. “However, there are some drawbacks to this method,” Fyffe says. “While contact systems provide excellent cleaning, contamination will build up on the adhesive roll unless it is checked and changed on a regular basis. This results in a gradual deterioration until the adhesive is refreshed and performance returns to 100%. As a result, tacky roller contact web cleaning may not be the ideal choice for more heavily contaminated materials.”
In this case, Fyffe explains, non-contact or vacuum contact cleaning provide an alternative solution, as the system performance is not affected by the contamination level and no consumables are required, which helps reduce ongoing costs. CyClean, Meech’s latest non-contact web cleaning system, is capable of removing contamination to below one micron and incorporates fluid dynamic principles to deliver higher levels of cleanliness for label printing applications.
“Despite static being a common phenomenon, we believe that some industries may not be fully aware of the impact it can have on their business. Meech has long recognized the issues caused by static and our most recent bars, the 971IPS and 929IPS, were developed as a response to customer feedback and provide efficient ionization from a 24V power supply. Combined with our range of web-cleaners, we are able to provide customers with the excellent standards of static elimination they have come to expect from the Meech brand.”
Simco-Ion, in developing its static control products for the label industry, has taken into account the prevailing trends affecting the greater label industry. One of these trends is the demand for presses that print at faster speeds, while maintaining efficiency and quality. “With these increased speeds comes the risk for higher contamination caused from static charges,” explains Marketing Manager Kim West. “Markets such as medical and food packaging demand high standards for cleanliness; therefore, it is imperative that these companies utilize products that will ensure contamination is removed,” she says.
Another trend West points out is the continued desire to print labels on flexible substrates. “As new flexible materials are introduced into the label converting process, manufacturers are under pressure to increase productivity and reduce costs, without compromising product quality. Unmanaged static electricity on flexible materials can cause print defects, machine jams, and prevent manufacturers from producing a product that meets their customers’ needs.”
Simco-Ion’s IQ Power is its most advanced static neutralizing system. West describes the IQ Power as “ideal for label converters who need smarter, more integrated, yet easy-to-use solutions to static issues.”
Offering upstream and downstream charge readings, IQ Power is a fully integrated system designed to provide exceptional ionization performance, with many patented features. IQ Power Static bars range from being engineered to neutralize static charges on webs traveling up to 3,000 fpm to providing powerful ionization for distances up to 30 inches from the web. The IQ Power system also offers complete monitoring intelligence. Through the user-friendly interface, the operator is easily notified if a bar needs cleaning or is in a fault condition. Data logging options are available with simple retrieval via USB or FTP.
If space is a concern, Simco-Ion’s Easy static neutralizing system offers superior performance with its high voltage power supply and static bar all in one integrated design. The system is IP66-rated for protection against particulate and splash.
Contact cleaning is the preferred method for the removal of debris, West says. The Teknek NWP is specifically designed for label and narrow web cleaning. She adds, “With the exclusive Teknek cleaning core, this product truly separates itself from others. The cleaning rollers efficiently control contamination, and the built-in static bar further eliminates static charges created from a web passing through the rollers. Teknek is ISO certified for increased confidence in safety, reliability and quality.”
Exair, Cincinnati, OH, USA, offers multiple static control systems for the narrow web market. According to Kirk Edwards, application engineering manager, choosing the best product for the application generally depends on two characteristics of the application. “First,” he says, “do you need compressed air assistance due to high speeds, or distance from the target? Second, what size area do you need to cover with the static eliminating ions?”
Edwards notes that non-air assisted products like Exair’s Ion Bars and the Ion Point should be mounted within 2" of the target. “These products are typically best for slower web speeds and are offered from 3" to 96" lengths. They do well on narrow webs because they have a small footprint and can be mounted in the tight quarters of many narrow web applications.”
For applications that run at high speeds, or when products cannot be mounted within 2" of the target, some air assistance is necessary, Edwards says. “The Super Ion Air Knife, Ion Air Cannon and Ion Air Jet are air assisted and supply air flow to break the boundary layer of air created by the high speed web. They are also capable of covering larger areas than an Ion Point or Ion Bar. Choosing the product to cover the right sized area is the next step – a Super Ion Air Knife to cover the width of your web or an Ion Air Cannon mounted remotely to flood an area where operators are getting shocked,” he says, adding that Exair’s most popular items for narrow web applications are Ion Bars and Super Ion Air knives.
Edwards also emphasizes that another major factor for a successful application is proper positioning. “Static elimination is a surface treatment and the ions generated by these products must come into contact with the surface holding a static charge. So, mounting strategy is important. Static will also regenerate with more vibration and friction of insulating materials. For this reason it is important to mount a static eliminator at the last place possible prior to the problem in the process for maximum effectiveness. If the static eliminator is positioned too far from the problem area, static may regenerate and continue to be a problem. If the narrow web or label process is long, more than one static eliminator can remove static from specific problem areas. Exair Static Eliminators can keep your web stock and rollers clean, they can remove and control contamination and provide a safe environment for narrow web press operators,” he says.
As more a narrow webs and labels are coated or made from films and run at higher speeds, Edwards believes static will continue to be on the rise. He says, “And since static electricity will cause a variety of problems, including contamination, reduced print quality and improper web feeding, static elimination will continue to be high on your priority list. If you want to keep up in this highly competitive market, the quality of your product may depend upon removing static from your process.”
Hurletron, based in Libertyville, IL, USA, represents Spengler AG exclusively in North America. Together, Hurletron and Spengler present a full line of active non-contact anti-static devices specifically designed to aid label printers. The company carries multiple products for the discharge of moving webs, from the traditional bar with power supply to its new TR line.
The Antistatic BEL transformer from Hurletron is an easy-to-use high voltage transformer for all ionizing systems. The Bel transformer is suitable for high-speed machines for discharging any kind of web or textile. The system is equipped with an automated overload shut-off, and sparks and cleaning detector. Optional on the Bel is an external on/off indicator for overload, sparks and cleaning.
Discharging with a distance of 20-30 mm, Hurletron’s new DC Ionizer TR operates with a pulsating DC voltage generated by an integrated power supply. Ions of both polarities are generated for contactless neutralizing of undesirable static charges on surfaces. Integrating a high voltage power supply eliminates the need for an HV cable with connector – the DC ionizer is connected directly to the power supply and is ready for use.
ElectroStatics, Inc., Hatfield, PA, USA, builds on its extensive experience designing static control products to deliver the latest technology web cleaner available. Standard widths are 8", 12",16", 18", 21" & 24". Custom sizes up to 30" in the narrow style are available. “Interest in web cleaning in the narrow web market – especially in the digital printing area – has been very high and we expect this to continue,” says Peter Mariani, president of ElectroStatics.
To meet the demand for static control products for the digital converting space, ElectroStatics has developed a line of web cleaners specifically designed for digital printing. The equipment features a grooved face plate that allows for the low web tension typically found in many digital presses. An enclosed dust collection system has a 0.5 micron filter, air compressor and power supply for the static bars in the hood assembly. “The dust collector system is very quiet, requires little maintenance and is on casters to make it easy to move,” Mariani says. “Web cleaners from ElectroStatics are the most cost effective way to insure your value added step is adding value and not creating scrap because of dirt on the web.”
ElectroStatics also features static bars, known as static eliminators or anti-static bars, products designed to be the most cost effective way to remove static electricity on a web of material in plastics, paper, glass, textile or film converting applications. “All of our static bars are bi-polar ionization generators (produce both positive and negative ionization) to remove static electricity.
Static bars from ElectroStatics come in four basic models, and with options such as air boost, can solve all static electricity-related problems. ElectroStatics offers a broad and cost effective line of static neutralizing bar equipment to control electrostatic charges and increase efficiency and productivity. The air boost option increases ionization range and assists in contamination control.