Patent attributes
A rotary device for high-speed printing or coating of a web substrate is disclosed. The printing system provides a gravure roll rotatable about an axis at a surface velocity, ν, and a fluid channel having a pressure drop throughout the fluid channel due to friction, Pf, disposed therein. The fluid channel is disposed generally parallel to the axis at a distance, Rin, relative to the axis. The fluid channel provides fluid communication of a fluid having a fluid vapor pressure, Pv, and a fluid density, ρ, from a first position external to the gravure roll to a web substrate contacting surface of the gravure roll. The web substrate contacting surface is located at a distance, Rout, relative to the axis. Rin is determined from the relationship:
