Often referred to as “the heart of flexo,” the anilox roll is critical for ensuring high-quality print for discerning brands. Any issue with the anilox – or its cleanliness – can significantly impact a print run in a negative way.

The function of the anilox roll is to deliver a controlled ink volume to the plate to reproduce the intended graphics. The proper volume is what allows printers to achieve a predictable and repeatable solid ink density, and the geometry allows them to reproduce the highest levels of tonal screen values and ink transfer efficiency.

“The cleanliness of these engravings will have a direct impact on the quality of work you achieve,” remarks Paul Teachout, technical marketing and content specialist, Harper Corporation of America. “A plugged or worn anilox roller will result in poor color control, ghosting, dot bridging and a host of other print defects that will result in downtime and material waste. Employing a properly structured anilox roller cleaning and measurement procedure within your operation will increase your quality, efficiency, and sustainability goals.”

There are many variables for printers to consider when deciding which anilox cleaning method is the best for their operation. Anilox rolls, for example, come in all shapes and sizes, and they can be constructed of mild steel or aluminum bases.

According to Teachout, the construction of the base materials must be considered when identifying the proper cleaning methods. “Aggressive chemical cleaners can attack these base materials, causing corrosion, which can then affect the ceramic coating,” he explains. Here at Harper, we offer the lowest levels of ceramic porosity in the industry to alleviate this concern. Ink chemistry can vary from high PH water based, solvent or UV and all require different cleaning methods to break down or dissolve inks. These different chemistries will have a major influence in your decision process. Each chemistry will present its own set of variables that need to be identified to ensure proper cleaning of engraved cells.”

The anilox engraving specifications play a critical role in the cleaning process, as well. These specs ensure the proper cleaner is being applied effectively to the engraving geometry. “You would not select the same cleaning process for water-based inks running line work on low line screen anilox rollers as you would for UV inks running high-definition process work on very high line screen anilox rollers,” Teachout continues. “Identifying all these variables will allow you to select the most effective cleaning process for your application.”

There are multiple cleaning solutions to keep in mind for flexographers. Liquid, ultrasonic, and laser cleaning are the common practices relied upon today. Anilox cleaning methods have certainly evolved over the years, too.

“From traditional hand cleaners utilizing stainless steel brushes to the more recent laser cleaning systems, they are all very effective when applied to the proper application,” says Teachout. “They can also destroy a roller if not utilized to the manufacturer’s suggested operating procedures.”

Automation has also become prevalent with the newest anilox cleaning technologies. For example, automation has provided new levels of efficiency as rolls can now be moved to the units and cleaned while operators pursue other activities.

“Hand cleaners are still widely used for on press cleaning, but the automated cleaning systems provide the deep cleaning that the rollers require on a regular scheduled PM cycle to continue to meet graphic requirements on-press,” comments Teachout. “Regardless if it’s manual, media blast, chemical or laser, all technologies have improved over the years providing safe and effective cleaning options for all applications.”

As an anilox specialist, Harper prides itself on serving as a beacon for converters. Harper offers multiple resources to help our customers identify the proper cleaning methods for their applications. The company boasts a regionally based Harper Technical Solutions Team to provide technical consultation required to identify the variables and recommend best practices for each facility the company visits. Meanwhile, the Harper Scientific division is a business unit that provides a full complement of environmentally safe cleaners and ink proofing systems for all applications. These resources are offered to all anilox roll partners to ensure they are getting the highest possible ROI of their anilox roller investment.

When tackling a solution for a specific customer, safety is paramount. “When recommending the proper anilox cleaning system for your facility, we first consider the safety of your employees and the effectiveness of the process selected,” explains Teachout. Consult with your anilox supplier so we can ensure that the rollers provided will be manufactured with the proper coatings and barriers to match the process. Understand the construction of your anilox roller so you can make informed decisions on cleaners and their impact on the construction. Work with our team of consultants who can provide all the technical information and employee training required for the proper cleaning, maintenance, and storage of your inventory. Regardless of the cleaning process selected, have a detailed plan and schedule of anilox cleaning and measurement to ensure consistent and repeatable performance of your inventory.”