What You Don’t Know About Ink Systems Part 2
Episode 2: Cleaning Anilox Rolls
>>Read Episode 1 on Shrinking Cell Volumes
When the last of the 60,000-foot label job was done it was time to clean the anilox rolls so they’d be ready for the job that would start the next morning. So the pressman got out the oven cleaner and went to work.
Oven cleaner? Or maybe some wheel cleaner meant to remove brake dust and road grime from alloy wheels? Or a little engine degreaser. Why not? After all, these substances are all harsh solutions intended to remove all manner of unwanted material from metal surfaces. Why not use them on anilox rolls to get inks out of those tiny ink cells?
Because they don’t do a very good job and can even seriously damage an expensive anilox roll.
“We’ve seen anilox rolls so corroded by use of improper cleaning chemicals that the doctor blades are unable to clean the ink off the roll,” says Andy Gillis, general manager of Provident. “That means the volume of ink being laid down is inconsistent and directly affects print quality.”
Provident routinely performs “ink audits” for its customers, thoroughly examining every element of a converter’s ink system, from the types of doctor and containment blades and end seals used to a company’s standard practices for press maintenance and operation to general care and feeding of anilox rolls.
Don’t try this at home
“Many shops use a single type of cleaner for almost every need,” says Randy Carter, technical sales representative at Provident. “And this is perfectly fine for a lot of applications. But anilox rolls deserve special attention.”
This is because the rolls are actually precision tools, designed to work in a certain way and do a very specific job. When any element of a roll is compromised it has a direct effect on print quality.
Gillis likens it to a common household cleaner like Simple Green. It’s a very good product, but it is not meant for use on glass. It can be used that way, of course, but it does not do as good a job as does a fluid meant specifically for glass surfaces. Many converters take a similar approach and use a single cleaner for all types of cleaning. And while those standard fluids do the job, each use still leaves a little more ink in anilox cells, a little more residue on the rolls, and before very long print quality begins to slip.
The challenge is further compounded with anilox rolls because of the many inks that are used for flexographic printing. Seemingly similar substrates, such as films, often require different inks to ensure proper adhesion and to be in compliance with various regulations, such as food contact. Because they are chemically different, those inks require may cleaning fluids that will thoroughly clean an anilox roll and its cells and not leave any residue that could compromise the next job being run.
“When we do an ink analysis we ask about all the applications and substrates and inks being used,” explains Gillis. “If they are all essentially the same we can offer a single cleaning solution that will do a fine job. But most converters have a few jobs that are sufficiently different that they should use a cleaning solution that accounts for the characteristics of the inks being used.”
Identifying the right solution
One of the challenges for converters is that the anilox roll cleaning market is a crowded space with little regulation and a low barrier to entry. “Especially at the regional level, the options abound,” says Carter. “Many of them claim to be all-purpose cleaners. Except they are not.”
Provident works with FlexoClean, a worldwide leader in cleaning chemicals, to fully analyze inks at the chemical level to determine the best mixture of cleaning fluids for a converter’s specific needs. With anilox rolls for a job costing hundreds or even thousands of dollars it makes sense to be just as careful in cleaning them as it does in handling and labeling them. To find out the best anilox roll cleaning options for your operation ask Provident for a complete ink system analysis and learn the best options for the unique mix of jobs that keep your presses running and profitable.