Spring Cleaning

ANILOX ROLL CLEANING is a necessary part of the printing process. Without proper care, anilox cells clog and lead to inadequate ink distribution, poor color densities, and difficulties in matching colors.

There are several cleaning systems on the market today, most suited for a variety of roll widths, diameters, and line screens. No matter what cleaning method is used, "Today's systems must be safe, effective, consistent, and efficient," said Wes Stone, technical manager at WS Packaging-Superior Label Systems (Mason, Ohio).

Chemical wash

Chemical wash systems clean aniloxes by enclosing the rolls in a washing machine where it is sprayed with a chemical cleaning agent. The detergent breaks down the medium on the roll, which is washed away by a high-pressure water rinse.

Max Daetwyler Corp. (Huntersville, N.C.), a distributor of chemical wash systems, recently introduced the Renzmann High-Pressure Washing Machine Type HA. The Renzmann HA is a closed, automatic spray jet washing machine for anilox rolls, anilox sleeves, and gravure cylinders. The Renzmann HA includes a special nozzle, which washes with a pressure of 100 bar, spraying the roller as it rotates.

Daetwyler also carries a smaller version of the Renzmann HA, called the Renzmann Washing Machine Type 50. Type 50 is a compact cleaning unit, designed specifically for label printers. The spray washer cleans ink pans, doctor blade holders, and splashguards in one 15- to 20-minute automated cycle. The

The Renzmann High-Pressure Washing Machine Type HA offered by Daetwyler

machine features the convenient "plug and wash" setup, requires no supervision while in use, and is used with eco-friendly chemistries.

Another company that provides chemical washers is Flexo Wash, LLC (Louisville, Ky.). Flexo Wash's FW Series Anilox Roll Cleaners, featuring "plug 'n play simplicity," are designed for all anilox roll sizes from 6˝ to 150˝. According to Michael Potter, general manager of the company, the FW Series Systems dissolve all types of inks, as well as adhesives, lacquers, acrylics, and other coatings with a hot, eco-friendly cleaning agent that is gently applied to the surface of the roll at low-pressure. The chemical is drained, filtered, and recirculated through the unit for use again and again. The anilox roll is then rinsed clean with a 1,400 psi blast of warm water at 100°F and dried with compressed air to eliminate corrosion. The anilox is ready for the press in 10 to 20 minutes. WS Packaging-Superior Label Systems, a primarily narrow-web printing company, uses a Flexo Wash high-pressure cleaning system as a means for safe, effective, consistent, and efficient anilox roll cleaning. "The solution we use with this equipment is non-caustic so as to protect our employees," said Stone of WS Packaging-Superior Label Systems. "This technique is low maintenance, cleans multiple rolls per cycle, and is not harmful to the anilox."

Media blast

The two most used forms of media blast systems are baking soda and plastic pellets. Blasting works by either placing the anilox in a contained, off-press machine or by enclosing the anilox on-press. Air pressure is then used to propel the media against the roll, which breaks down the anilox deposits and unplugs the cells. "This is a satisfactory method, but must be done with care," said William Jenkins, pressroom team leader at Plastic Packaging (Hickory, N.C.), which uses baking soda blasting as one way it cleans anilox rolls. "Damage can result from excess air pressure and faulty blasting machines. Media blasting works as well as the people who use it."

Anilox Roll Cleaning Systems (Hatfield, Pa.) offers baking soda blasting machines, all manufactured by Sani-Blast, Inc. (Spring Grove, Minn.). ARCS' machines are automatic, have 100 percent dust control, and use Armex Blast Media, a soft crystalline form of Arm & Hammer Baking Soda. The water-soluble Armex is blasted at the rotating anilox roll at 30 psi. Upon impact, the 70-micron baking soda particles breakdown to as small as 8 microns, acting like little knives as they get inside the smallest cells to lift the inks away, said Jim Heffer, president of ARCS. The ARCS system cleans anilox roll sizes 4˝ up to and beyond 220˝, on- and off-press.

Specializing in anilox cleaning systems using plastic media, Absolutely Micro*Clean International (Rancho Cordova, Calif.) has a new anilox cleaner for narrow-web printers. The NW 16A is a vertical, free-standing anilox roll cleaner that was "designed for a narrow footprint," said Micro*Clean President Bob Temple, "since most narrow-web printers don't have a lot of extra space to accommodate new machinery." The NW 16A cleans with the same effectiveness as the company's other enclosed, blasting systems. The NW 16A also uses the same non-hazardous, non-abrasive, recyclable plastic media, which comes in three blends: standard, used for all size rolls; heavy duty, an extra fast media for large rolls; and ultra fine, for rolls with high screen lines. "Most of our clients use a mix of these," said Temple.

Ultrasonic

Ultrasonic cleaning machines de-ink aniloxes using sound waves. For the best results, aniloxes are soaked in a cleaning solution for 90 percent of the cleaning time. Then the ultrasonics are turned on and sound waves create microscopic bubbles that implode against the roll, agitating the ink loose and away. The key to ultrasonics is the right combination of chemical soaking solution, heat, and time that the roll is exposed to the sound waves, according to Marty Cansler, national sales manager of pressroom products for Max Daetwyler.

Max Daetwyler offers ultrasonic cleaning systems that clean up to six rolls at a time. Daetwyler's ultrasonic machine comes with electronically controlled frequencies for even cleaning and automatic power stabilization circuits which monitor and adjust the generator operation to assure steady power delivery.

AAA Press International (Arlington Heights, Ill.) is another company featuring ultrasonic cleaners. AAA Press distributes ultrasonic systems from Sonic Solutions (Lockport, Ill.) that can simultaneously clean one to six rolls, ranging in length from 10˝ to 38˝. Sonic Solutions' systems are set to a specific frequency to reduce the potential of misuse, said Mark Hahn, vice president of sales and marketing at AAA Press. "Too often, people set the machine at an improper frequency and they cause damage to the roll," he said. In Sonic Solutions' machine, rolls are rotated and soaked in a solution heated to 120 to 140°F before the ultrasonics is used to dislodge the set-in media.

Brushes

Removing anilox rolls from the press to be cleaned after every job is not always an option. That's where hand cleaning with brushes is necessary. Stainless steel brushes should be used on ceramic aniloxes, while brass brushes should be used to clean chrome rolls.

While Harper Scientific (Charlotte, N.C.) offers both stainless steel and brass brushes, its Poulsonator Auto Brush helps take the elbow grease out of brush cleaning anilox rolls. The hand-held Poulsonator provides dual brush scrubbing action using compressed air that creates the desired circular cleaning motion. "The Poulsonator holds two stainless steel brushes and cuts manual cleaning time in half," said Dan Foy, technical product specialist at Harper Scientific. The Poulsonator can be used on- and off-press.

-By Kate Sharon, Associate Editor