Ink evaluation and digital application

- Assessing Inks, Dealing with Digital-the NPIRI Conference

The American Printing Ink Institute held its 44th Technical Seminar in Songshan, Georgia, in October 2000. The participants at the conference were very enthusiastic. The activities included short-term UV/EB curing inks and digital printing technology in the information era.

The release of the NPIRI Technology Achievement Award is the focus of this conference. This prestigious award was awarded to W. Zawachi of Flint, who participated in the ISO and NPIRI Committee ink color standardization and transplanted color management into color science. About 25 years ago, I started working on several key color projects.

Eco-friendly people submitted an interesting paper, “Flexographic Printing Ink Options: Evaluation of Harmless Ink Composition”. In the article, the development prospects of solvent-based inks, water-based inks, and UV-curable inks in terms of cost, energy, environment, and health are compared. It includes 45 ink formulations.

Solvent-based, water-based inks are very similar in terms of average index, but the order of ink performance is as follows: 1. Solvent type; 2. Ultraviolet curing; 3. Water-based ink.

However, the cost is mainly determined by the speed of printing. Studies have shown that at the same printing speed, water-based inks are the most economical, followed by soluble inks and again by UV-curing inks.

In terms of the environment, water-based inks contain more unstable organic compounds than solvent-based inks, and water-based inks are more costly than solvent-based inks in controlling the promotion of oxidation of unstable organic compounds. Compared with UV-curable inks and soluble inks, water-soluble inks exhibit the lowest energy consumption. All inks are harmful to unprotected workers.

The assessment of the harmlessness of the ink composition is as follows:
1. There is no system that can have a clear advantage over the ink's innocuousness.
2. Some water-based inks and UV-curable ink formulations have higher environmental, health, and safety requirements.
3. Little is known about the toxicity of many ink ingredients.

It is clear that digital printing is what ink manufacturers think. For the average ink manufacturer, digital printing is a threat. It is expected that many of our ink manufacturers will invest in the digital era.
Take Toyo Ink Co., Ltd., which is famous for its high-tech operations. In 1979, Toyo Ink introduced the first digital prepress system. It also supports Angel's first flatbed scanner in 1985 and the Indigo digital press in 1990. Toyo Ink now participates in the study of electrocoagulation imaging.

Toyo Ink Co., USA Branch introduced the electrocondensation imaging technology. Since 1995, Toyo Ink Corporation and its US subsidiary have jointly developed this technology and have published and registered more than 32 patents in Europe, Japan, and North America.

Electrocoagulation imaging is a digital printing system based on the electrocondensation of electrolytically sensitized polymeric water-soluble inks. This process involves the application of very brief current pulses to the conductive ink solution between the cathode array and the passivated rotating anode. The ink adheres to the positive electrode and is transferred to a white paper. By adjusting the current pulse time for each electrode, the volume of each coagulation point is controlled to increase in small increments, so that the continuous tone image is written at a fast rate of 4 microseconds/point (200 feet per minute).

The new ELCO 400 press has already achieved double the print speed to 400 feet per minute with an image resolution of 400 dots per inch. With a resolution of 400 lines/inch, the printer's rated write speed is 15 meters/second. See the details of this technology.