The proper handling of flexographic supplies, such as anilox rolls and plates, is often one of the most overlooked aspects of high-quality label printing. Degradation in printing results can often be attributed to improper storage and handling of  “the heart of flexo” – the anilox roll.

According to Paul Teachout, technical marketing and content specialist, Harper Corporation of America, 80% of the rollers Harper remanufactures are damaged and not warn – and mishandling is a
prime suspect.

“The ceramic compounds of the roller measure over 1,200 Vickers in hardness,” explains Teachout. “They are very dense, hard materials and are very wear resistant, but they do not like impacts due to the brittle nature of the ceramic. Implementing the proper storage and handling practices will protect your rollers and extend their life.”

But where and how should anilox rolls be stored? There are a number of considerations in preventing damage to these critical tools.

“In many cases, if anilox rolls are not stored properly, they could easily get nicked or dropped, which could be prevented if the roller was properly stored and wrapped,” remarks Aaron Lessing, VP of business development, Apex International. “We strongly recommend that anilox rolls or sleeves are stored in a low traffic area and also covered with either a hard plastic cover or a heavy vinyl cover. The hard plastic covers allow the operators to load the roller into the press (which is a concern for damage) with the cover on. In other words, many times a roll will get damaged as it is going in and out of the machine.”

Andy’s Roll Covers, a Fort White, FL-based supplier, was established in 1985 to provide impact protection for cylinders in the print, package, and impression industry. The company offers a wide range of solutions for anilox maintenance care. According to the company, the covers are cost effective, solvent-resistant, and easy to install. 

“Andy’s Roll Covers provide a custom fit first-line of defense that perfectly fits the diameter and face length of the roll or sleeve,” says Jessica Phelan, senior operations manager, Andy’s Roll Covers. “Andy’s Roll Covers are a soft, thick, pliable vinyl and come padded (Ultima) or unpadded (Standard) with or without edge protection, depending on the roll’s needs and preferences. Their use has saved the industry millions of dollars by protecting rolls from gouges, drag marks, dinks, dents, cracks, and chips. They also serve well as dust covers and prevent contamination of the roll’s surface from oil, ink, and grease. Once any roll cover becomes soiled, it is recommended they are either cleaned or replaced so the engraving surface does not get contaminated with grease, oil, or ink residue.”

Any degradation to the anilox can impact print quality. The anilox roller, by nature, is a precise tool that delivers a predetermined ink film to the substrate. This process is all done at a sub-micron level. Therefore, the slightest imperfection can be quite costly.

“Any contamination or debris can greatly affect the anilox roller performance on-press,” says Teachout. “This can relate to volume and/or color loss or finding blemishes in the print. We must remember that anything on the anilox roller surface, be it contamination, plugged ink or surface blemishes, will surely show up in the print. This will relate to unwanted downtime and material waste. Anytime a roller is put back in storage it should be properly cleaned, inspected, covered, and logged of its condition. There is no worse feeling for an operator than to find the anilox required for the job is either dirty or damaged and returned to the rack.”

There are a multitude of factors to consider for anilox maintenance, especially once the rolls are in storage. “While in storage, many companies leave Andy’s covers on their rolls until the rolls are needed,” explains Phelan. “When the rolls are needed, the rolls are moved from storage to the press with the covers intact.  After the rolls are installed on the press, the covers are then removed by sliding off the roll or by unfastening the Velcro enclosure. The covers are placed back on the rolls when the press job has been completed, and the rolls are then moved back into storage.”

Current print environments have become very analytical, in that the measurement and collection of data has been relied upon heavily to inform production decisions. The goal, ultimately, is to deliver a consistent and repeatable operation.

“One of the most important measurement tools a converter can implement is an anilox measurement device,” comments Teachout. “Not just a visual scope but an actual measuring device to identify proper volume and line screen. We always measure color after the fact. Would it not be wise to measure the roller that provides the color before you put it on the press or on the rack? Anilox roller measurement devices are now very affordable and practical. In my opinion, these devices will not only have a rapid ROI in waste and startup, but also streamline your anilox inventory and help meet sustainability goals.”

When considering the maintenance and care of anilox rollers, converters should feel confident in leaning on their suppliers for support.

“We at Harper have a legacy and a culture of continuous education and support,” states Teachout. “We have a complete team of FTA-certified technical representatives that are available to assist our partners with any level of production management. From roller audits to press characterizations, care and maintenance training to regional road shows,  our commitment has never wavered. We offer the highest quality product with the best technical support, and educate our partners to exceed their expectations.”

Meanwhile, Apex International has instituted numerous processes and procedures to ensure performance for their customers. “Apex can offer complete customer support with respect to advising anilox roller specification properly,” explains Lessing. “We will then take responsibility if the spec is not correct. In addition, we can partner with your print and maintenance departments to help guide them with Use & Care seminars and audits of the anilox. Periodic support from Apex helps to monitor the overall condition of the anilox.”

Andy’s Roll Covers offers a wide range of solutions that have been optimized for the modern flexographer. “Most roll storage systems can accommodate either the Standard or Ultima Andy’s Roll Covers with the edge protection,” states Phelan. “Sometimes there are room or other constraints that make it impossible to use the covers with the edge protection. When this happens, the covers without the edge protection are a perfect solution and can be custom-cut to a required, specific length.”

Evolution of anilox technology

The anilox roll has long been referred to as the “heart of flexo,” and for good reason. The purpose of the anilox is to deliver a predetermined, controlled, and even amount of ink, every time.

“To accomplish this, it is critical that the anilox supplier has quality control, not only of the corrosion barrier and ceramic spraying process but also in the engraving and finishing processes,” states Apex International’s Lessing. “If these are not done consistently from drive side to operator side from roll to roll, quality can be an issue due to the anilox manufacturer.”

Recent developments in ceramic coatings and laser technology allow Harper to offer the traditional 60-degree hexagonal geometry with a channeled application technology. This 60-degree channeled engraving offers all the traditional strengths of a measurable volume, proper dot support for process, smoother solids for spot colors and higher opacities with reduced pin holing. It also greatly reduces UV ink spitting by reducing the pressure built behind the meter blade.

According to Harper’s Teachout, the 60-degree channeled application technology is the next generation of anilox innovation. “Harper has and will continue to make significant investments into the development of surface coatings and fiber optic laser engraving,” he says. “These innovative steps have allowed us to continue the development of ceramic compounds and new engraving geometries. Harper pioneered the 60-degree hexagonal geometry almost 40 years ago, and it remains the predominant geometry for flexo printing today. There are obviously many other geometries that offer value for specific needs, but the hex is still known as the workhorse.”

As with other segments of the label and package printing industry, anilox roll technology has evolved considerably over the last decade. Therefore, proper handling is critical to ensure that the technology is transferred to print performance.

“Anilox technology in the last 10 years has improved dramatically thanks to much more consistent laser technology, more refined powders, and better finishing techniques,” says Lessing. “The mystery of making an anilox is over, and if done properly an anilox can last and perform for many years.”