It is surprising that something has common as ink that we use for writing has been innovated in so many ways but not too many innovations are successful. The purpose of ink, whether in a pen on paper or in printer on paper has been primarily used to display objects on paper and that is what it has been primarily used as, nothing fancy seems to work. There are exceptions of course: like the ink that is used in e-book displays like the Kindle, Nook or e-reader which has been very successful but that is combined with all the electronics that make it very useful. Similarly, printing inks that make defined conductive surfaces have been manufactured by many companies to serve as printed circuit boards and other and other uses but they are one specific application of a coating process, rather than just ink.
Consider, color changing inks. These were first announced in a Advanced Materials article in 2003 by Ozin and Manners from University of Toronto. This was interesting design. The ink changed color upon solvent interaction. This was enabled by spheres embedded within a solvent sensitive gel. When the gel changed shape, the distance between the spheres changed and the diffraction of light changed. This changed the reflective properties of the surface. Neat idea that needs application.
Here is another: Ink that changes resistance upon changing shape like a flex sensor. This is a good idea that has been incorporated as a suspension in a sensor like this one. However, this ink will never be used to print a book or be used in that area but it did get incorporated into flex sensors in many areas.
Conclusion: Novel ideas by themselves do not make useful articles. The fulfilling of the need or recognizing a non-vocalized need by the novel idea makes a great device or article.
