Printing paper with UV light

Thanks to an especially developed coating it is now possible to repeatedly print paper with uv light. Chinese scientists developed the coating made from 2 types of nanoparticles, Prussian blue and titanium dioxide. By mixing the two and spraying it onto paper a blue colour appears. When the paper is exposed to uv light, the titanium dioxide releases electrons which are absorbed by the Prussian blue. The blue colour then turns colourless. So, by exposing the background of the text to the uv light it becomes white and by not exposing the text to uv light the text remains blue. After printing the text remains visible for 5 days at high resolution. Deleting all text is possible by heating the paper to 120 degrees Celsius. This way the paper can be reused up to 80 times.