Photocopiers use an electrostatic drum to form the image then transfer it to the paper.
Transparent Titanium Dioxide? If you can get some samples from a supplier of sunscreen raw materials this would prove a point. BASF (Z-Cote), Croda/Uniqema(Tioviel), Mitsubishi, Merck (Eusolex-T-AVO) and others make them. Be aware that there are two different crystal types of titanium dioxide. (Rutile and Anatase)One is photocatalytic, the other inert. This was found out when in the 50's white lead was beginning to be replaced with Ti02. Using the wrong crystal type makes the paint fall apart in sunlight.
This sort of question might get a better response on the Hybridphoto.com website