Enhancement of ink flow ducts with high surface energy material inclusions

An enhanced flow duct apparatus for communicating a liquid between a reservoir source and an outlet, a flow of liquid through the duct apparatus being cycled between on and off states, said off state stopping flow of said liquid and enabling formation of slugs of liquid having a longitudinal length, said slugs being trapped in the duct apparatus and separated by air pockets resulting in increased impedance to flow, the duct apparatus enhancing reestablishment of liquid flow in a subsequent on state including reduction of necessary pressure head at said reservoir source, the apparatus comprising:

• a valve for cycling the flow of liquid between said on and off states;
• a small diameter tube of a low surface energy material for communicating said liquid between said source and said outlet, said tube having an inner tube wall;
• and
• a member of a high surface energy material in the form of a spring located adjacent said inner wall and extending within said tube substantially from said source to said outlet, said member having greater surface tension and wetting forces between said liquid and said member than surface tension and wetting forces between said liquid and said inner wall to overcome the impedance of the slugs, said spring having a pitch at most equal to an average longitudinal length of said slugs.