Chambered doctor blades are now standard on central impression (CI) presses and high definition (HD) corrugated post printers. Over time, HD flexo corrugated post printers have evolved from rubber fountain roll to 100 percent reverse angle chamber systems, as have CI presses for flexible packaging.
The reason for this has been higher print quality. On press automatic washup systems are also standard on CI machines and now are following suit on corrugated post printers.
The “Next Big Thing” is improving chamber performance to reduce ink and cleaning solution waste. On average, half of ink purchased is not applied to the substrate. This can be a large financial burden on printers. Environmental regulations will continue to get stricter, calling for better ways to reduce the cost to deal with this waste stream.
A large proportion of this ink is in waste cleaning solution, and in order to dispose of it, the majority of printers have cleaning (or flocculation) plants. This has several effects:
Photos courtesy of Novaflex
- The average cost can run up to $100,000 annually, depending on total print volume
- The costs for the chemicals to clean the ink are also expensive
- The residual waste goes to a landfill
What is Chamber Technology?
Chambers can help with these problems. There are some key points and things to consider that, taken together, will help propel the printing industry to the next level of quality and cost savings. They include:
- A high flow rate of ink and coating to significantly reduce micro bubble formation
- The ink level inside the chamber must be controlled in order to reduce air entrapment in the ink, while at the same time not over pressurize the chamber, which can cause leakage
- A small chamber cross section, which can reduce the end sealing area to minimize leakage
- Back doctoring of the containment blade, which scrapes off the residual ink on the anilox roll as it reenters the chamber
- Ink saving from the reduced volume of the chamber and special treatment of the carbon fiber surface with an antistatic resin
- On press cleaning with no contamination during color changes
- Reduced downtime through faster on press cleaning
- Faster press speeds with less chamber bounce
Carbon Fiber Vs. Aluminum
Historically, the standard ink chamber system has been made from aluminum, mainly due to its light weight and lower cost. However, because of maintenance and corrosion problems seen over time, the industry is now looking at carbon fiber chambers as costs continue to come down. Anti corrosion carbon fiber is not subject to any degradation caused by water based inks, solvents and glues. It offers the best resistance against corrosion over the long term.
Carbon fiber is 300 percent stronger than aluminum, and does not expand with heat. It offers the best contact adherence to the anilox roll and reduces vibrations, even on wide machines. And it is 70 percent lighter than aluminum, and because of this, presses can run faster.
Carbon fiber is also coated with a resin with excellent antistatic properties in order to easily remove any ink trace. As a result, the cleaning of the chambered doctor blade is very quick and easy. This also leads to a considerable reduction in water or solvent consumption while washing the ink circuit.
Managing Pressroom Efficiencies
When companies run up against machine capacity problems, they often consider working overtime, adding shifts or purchase new machines at great cost. Instead, they should consider improving the performance of their existing flexo presses.
By minimizing changeover times and improving operator performance, print quality is also optimized. In all this, the “devil is in the details.” For the older CI presses producing flexible packaging and for the corrugated market, the big push is for HD flexo post printing, which can be realized through upgrading to carbon fiber chambers and automatic washup systems.
About the Author: Wallace Nard’s career in the printing and converting industry spans more than 55 years. He started his career in flexo in 1957 and in 1989 formed Novaflex, a printing and laminating sales/service group based in suburban Chicago. Nard is the president/owner of Novaflex, located in Carol Stream, IL. He has held numerous positions in FTA’s committees and was inducted into its Hall of Fame in 1988. Learn more about Novaflex at www.novaflex-inc.com.