Treat it Right
The wide range of substrates and ink systems being used makes corona treatment a key tool for package printers.
by Tom Polischuk
PACKAGE PRINTERS ARE dealing with a multitude of market conditions that have them pushing the envelope when it comes to the materials they run. Because of the need to hold onto business, replace lost business, or grow sources of new business, package printers are routinely running a wider variety of substrates, along with new inking systems. This includes a continuing trend toward the use of film substrates (including thinner gauge films and conductive foils) and new inks such as UV and water-based systems.
Not surprisingly, many of these applications have narrower processing windows while quality and productivity demands are higher. However, one of the proven tools in the printing arsenal is the use of corona surface treaters to improve ink adhesion and overall print quality.
It is typical for film substrates to be corona treated by the supplier prior to delivery to the printer. There are several reasons why this may not be adequate says Jan Westerheim, president of Solo Systems (Rowlett, Texas).
For starters, the impact of treating dissipates over time, so material sitting in inventory for a number of weeks may not be at acceptable levels for quality printing when it is used. Add to this the variability that comes with different suppliers, some of which may be foreign companies, and Westerheim makes the case for bump treating at the printer's facility. Since bump treating is done to basically even out surface tension and re-establish previous levels, she points out that, many times, corona treaters used in these applications don't require lots of power.
Corotec's (Farmington, Conn.) VP of Sales, Ron Seaman, says that a solid part of its business is in retrofit applications, and these include both materials suppliers and printers. With more use of water-based and UV inks, surface treating is required in more applications. Throw in the wide variety of additives used in film substrates, and the addition of inline bump treating is getting more common. Seaman adds that because of the overall market trends, corona treaters are typically installed on new presses.