Think Ink

Although many substrates are recyclable, it is difficult to find and implement programs with recyclers that handle them. One notable Exception is Tyvek-based products for UV, solvent and water based inks for which a recycling path is provided. (Photo courtesy DuPont)

We have heard a lot of “green” words and rebranding of existing products as now being “green” or “sustainable”, but what is really being done to move away from the “evil” vinyl and solvent ink products that have been the staple of the digital sign and graphics business? It is difficult to replace vinyl with an equivalent “greener” substrate since vinyl is so cheap and durable. Solvent inks are the lowest cost inks and print directly onto uncoated vinyl with excellent results. The printed graphics resulting from the use of these components provide a very good, very low cost solution for many applications—but they are anything but “green”! Here we look at some of the serious efforts to go beyond rebranding and move toward real systems that provide greener and more sustainable solutions.

MILD SOLVENT SOLUTIONS
For several years now, work has been under way not to exactly replace solvent inks, but rather to make them less hazardous, less unpleasant to work with and/or bio-sourced or biodegradable. This category includes mild solvent, light solvent, eco-solvent and bio-solvent inks. Along with these inks came new media, in particular polyolefin media (polypropylene and polyethylene based media) as an alternative to vinyl. Often coatings or other treatments are required for the new substrates to perform adequately with these inks. The substrates tend to be more costly and sometimes provide less strength and outdoor durability than vinyl, but in many cases they are recyclable, which is a strong “green” benefit.

However, the ability to recycle and the actual process of recycling are two very different things. Very few systems are in place to recycle these materials, so they frequently end up in the land fill just like the vinyl they are trying to replace. One notable exception is Tyvek-based products for UV, solvent and water-based inks for which a recycling path is provided and readily available.

UV SOLUTIONS
Another approach is the use of UV-curable inks. These, when properly formulated, can provide a much less volatile material than any other ink technology. Their biggest drawback is the cost of the ink and the expensive equipment required to print with them. Some may say that over time the ink cost will come down, and to some extent it already has. But unlike water-based and solvent based inks where 70% or more of the ink is water or an inexpensive solvent that evaporates after application, with UV-curing inks the entire ink droplet is polymerized during curing and none goes to waste, even though UV-curable inks contain expensive ingredients.

UV-curable inks, when properly formulated, can provide much less volatile material than other ink technologies. This solution is becoming much more popular and can provide a good alternative to solvent inks even on uncoated vinyl.

Again, if you want to print onto the vinyl substitute materials, a treatment or coating is required that does increase the cost; however, the UV-cure printing solution is becoming much more popular and can provide a good alternative to solvent inks even on uncoated vinyl. This is especially true for grand-format printing where strong solvents have dominated.

This October, HP announced a new version of the Latex ink printer, as well as several new media treated to work with these inks. The Designjet L25500 printer (available in 42” and 60” versions) will be priced competitively with mild-solvent printers available in this printing width. The unit has many of the same environmental features as its grand-format brother, but also includes features from HP’s Z series of photo printers such as automatic maintenance systems, user-replaceable printheads and an embedded spectrophotometer. Unlike the mild solvent printers, these Latex ink printers require no special ventilation to meet OSHA requirements on occupational exposure to VOCs.

HP’s newly released Designjet L25500 latex-based printer series can image directly onto vinyl as well as onto many vinyl alternatives. The unit has a green footprint and output and consumables can be integrated into HP’s new recycling program, a step which addresses a major concern of print providers who are interested in becoming greener.

LATEX INK SOLUTIONS
Hewlett Packard introduced the 104”-wide Designjet L65500 printer last year, which was the first example of a new technology using what they call Latex inks to print directly onto vinyl and on many other vinyl alternatives. These inks contain about 70 percent water and the remaining liquid is a mixture of organic solvents like those in desktop printers. A family of treated or coated media was introduced, some of which can be recycled. The printer addressed the narrower range of the grand-format applications and was priced accordingly.

In addition, HP has provided a more robust recycling program, a step that addresses a major concern of print providers who are interested in becoming greener, but who do not have resources to set up their own recycling programs. In addition, HP has developed a free printhead and print cartridge recycling program along with a media take-back program for those serious about recycling.

CONCLUSION
As an industry, digital sign and graphics is making a lot of progress in replacing vinyl and solvent ink systems of the past with much greener and more sustainable solutions. It is great to see the commitment of the major printing systems providers to a serious program to reduce the use of these materials, provide the industry with cleaner and greener alternatives, and in addition, provide the systems to enable the recycling of the used consumables as well as the final printed graphics while minimizing the energy consumed. Their support of certification and commitment to programs such as the SGP (Sustainable Green Printing Partnership) is commendable.

(Click here to read Part 3 of this article series.)