' Suspect' Digital Printer Rolls
The original and approved printer rolls have a third and final top coating in order that the thermal image cannot be defaced or obliterated by solvents, liquids etc. being absorbed by the priinter paper. There are some rolls being sold that do not appear to have that top coating, in fact they appear to be ordinary till roll thermal paper. If you mark the face (the plain side) of the roll with a marker pen, it should rub off, and not be absorbed into the paper. If it does not rub off then the paper does not have the top protective coating. The paper is considered to be an integral part of the Digital Tachograph (VU) and if it does not conform to the specification of the original which was submitted with the VU when it was approved, then the whole VU is considered to be not legal. The paper submitted by SiemensVDO had the final top coating as do our Eurodisc rolls.