Ink Transfer in Flexo Evaluated by X-ray Fluorescence

Flexography has shown a dramatic rise in print quality and it is more important than ever to understand the process and to identify those parameters which affect the print result. For full control over the ink transfer it is necessary to measure the ink amount on the anilox roller, the printing plate and the paper. In this paper the use of X-ray fluorescence for measuring the amount of ink on the plate and paper is discussed. The results shows that the technique seems to be very suitable for this purpose, particularly because of its easy performance and high accuracy. Earlier studies have shown that IR-technology can be used for on-line studies of ink transfer in a flexo press. However, this paper also describes different methods that can be used for measuring the ink film thickness and suggestions concerning further investigations.