The best kept secret is an Asymmetric chamber design, in combination with thinner doctor blades!
About 10 years ago the first truly asymmetric chamber NOVA XLS was introduced by AkeBoose Graphic Products. The Swedish engineer Åke Bööse had found out that different blade angels are the key to eliminate problems with back doctoring. The results also proved to be even better when using thinner doctor blades. By using a high quality sealing/retaining blade of 0,15 mm thickness, at a flatter angle, the thin and flexible sealing blade allows superficial ink droplets on the screen roller, to re-enter the chamber, instead of dripping down or spreading side-ways to the roller ends.
The NOVA XLS Robust chamber is made from the same asymmetrical chamber body as NOVA XLS Closed, but equipped with special ink outlets, including end-houses, to prevent problems with air bubbles and ink starvation.
The combination of optimal blade angels and low pressure doctoring is the basis for high productivity. Provided with end-houses the NOVA XLS Robust chamber is very reliable and cost efficient for very long print runs (up to 1 million meters).