Assessing Inks, Dealing with DigitalThe NPIRI Conference

The National Printing Ink Research Institute (NPIRI) held its 44th Technical Conference in October in Pine Mountain, GA. The well-attended event included short course sessions in "The Basics of UV/EB-Curable Inks" and "Digital Printing Technologies for the Communications Era."

A highlight was the presentation of NPIRI's Technical Achievement award. This prestigious award was given to Walt Zawacki, Flint Ink Co. Walt has been instrumental in contributing to ISO and NPIRI committees' standardizing ink colors and moving color management to color science. It was a pleasure to see Walt receive this award as he worked with me at American Can Co. some 25 years ago, and he was instrumental in several key color projects.

Karen Chu of the Environmental Protection Agency offered an interesting paper on "Flexographic Ink Options: A Cleaner Technologies Substitutes Assessment (CTSA)." She compared solvent-based, water-based, and UV-curable inks on wide web from cost, energy, environmental, and health perspectives. More than 45 formulations were involved.

Solvent- and water-based inks were found to be competitive on the average, but the best ink performances were in the following order: 1. solvent-based; 2. UV; 3. water-based.

While cost is mainly driven by press speed, the study found that at equal speeds, water-based inks had the best economics followed by solvent-based inks, followed by UV inks.

From an environmental perspective, volatile organic compounds (VOCs) were higher for water-based inks than solvent-based inks where catalytic oxidation is used to control VOCs. Water-based inks showed the lowest energy consumption compared to UV or solvent-based inks. All the inks had systemic and developmental risks to unprotected workers.

CTSA conclusions were as follows: 1. There is no clear "winning" system.

2. Some water-based and UV-curable ink formulations offer superior environmental, health, and safety profiles.

3. We know relatively little about the toxicity of many ink chemicals.

Clearly, digital printing was on the minds of ink makers. Digital printing is a threat to conventional ink makers, and we can expect to see many of our ink suppliers take the plunge into the digital age.

An example is Toyo Ink Co. Always known as a highly technical operation, Toyo introduced the first digital prepress system in 1979. It also supported Scitex's first flatbed scanner in 1985 and the Indigo Digital Printer in 1990. Today, Toyo is involved with Elcography.

Taro Watanabe of Toyo Ink America Inc. gave a presentation on the Elcorsy Technology. Elcography was invented and developed by Elcorsy's founder and president, Adrien Castgnier. Since 1995 Toyo and Elcorsy have jointly developed this technology and have secured more than 32 issued and pending patents in Europe, Japan, and North America.

Elcography is a digital printing system that is based on the electro-coagulation of electrolytically sensitized polymeric water-based inks. The process consists of applying very short electric pulses to a conductive ink solution in between an array of negative electrode (cathode) and a passivated rotating electrode (anode). The ink adheres to the positive electrode (anode) and then is transferred onto plain paper. By modulating the electronic pulse time for each electrode, the volume of each coagulated dot is controlled in very fine increments, allowing true continuous-tone imaging at a very fast writing process speed of 4 microseconds/dot (200 fpm).

The new press, the ELCO 400, has doubled the printing speed to 400 fpm at an imaging resolution of 400 dots/in. At a resolution of 400 lines/in., the nominal writing speed of the press is 15 m/sec. You can find out more about this technology at elcorsy.com or twatanabe@toyoink.com.


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