Bemis are one of the largest printing companies in the United States. They were asked by one of their customers, Kimberley Clarke, to print a 2-colour design on their children's nappies which is designed to disappear as soon as the child relieves itself. The machines which they already used for printing this material were 6-colour common impression flexographic printers. One of the colours already used was a normally invisible fluorescent dye. This was used to print a registration mark which was already used further down the production process. The solution was to add a two colour press electronically. Pan Controls supplied a control system to map the position of the main press onto the motion of two new colours. Registration control was provided by monitoring the fluorescent registration mark with an ultraviolet detector. The material which was being printed was particularly stretchy, and posed considerable control problems. Any small variations in tension stretch the material. In addition, very high throughput was required to make the whole process economic (1200 ft per min).

Pan Controls managed to achieve a tolerance of ±0.5mm at a speed of 1200 ft per min. This enabled Bemis to expand their 6 colour printer without having to do any significant mechanical modifications on the existing printer.

Pan Controls Limited