Passive valves in a printhead

A printhead comprising:

• a plurality of jetting channels each comprising a pressure chamber, a first channel fluid passage that fluidly couples the pressure chamber to a first common manifold, and a second channel fluid passage that fluidly couples the pressure chamber to a second common manifold;
• a first passive valve disposed in the first channel fluid passage, the first passive valve configured to inhibit a back flow of print liquid from the pressure chamber towards the first common manifold and allow a flow of the print liquid from the first common manifold towards the pressure chamber;
• and
• a second passive valve disposed in the second channel fluid passage, the second passive valve configured to inhibit a back flow of print liquid from the second common manifold towards the pressure chamber and allow a flow of the print liquid from the pressure chamber towards the second common manifold, wherein
• the first channel fluid passage and the second channel fluid passage each comprise a top wall, a bottom wall, and opposing sides walls;
• the first passive valve and the second passive valve each comprise at least one fixed valve member disposed between the side walls, and physical separations between the at least one fixed valve member and the side walls are configured to form flow paths on opposing sides of the at least one fixed valve member.

A method comprising:

• operating a printhead, the printhead comprising:
• a plurality of jetting channels each comprising a pressure chamber and a channel fluid passage that fluidly couples the pressure chamber to a common manifold;
• and
• a passive valve disposed in the channel fluid passage, the passive valve configured to inhibit a back flow of print liquid from the pressure chamber towards the common manifold and allow a flow of the print liquid from the common manifold towards the pressure chamber, wherein the passive valve comprises at least one fixed valve member disposed between opposing side walls of the channel fluid passage, and physical separations between the at least one fixed valve member and the side walls are configured to form flow paths on opposing sides of the at least one fixed valve member;
• wherein the operating comprises:
• conveying the back flow of print liquid along at least a portion of a length of the channel fluid passage from the pressure chamber toward the common manifold;
• and
• inhibiting the back flow in the channel fluid passage with the passive valve by:
• dividing the back flow into the flow paths with the at least one fixed valve member;
• and
• recombining the print liquid of the flow paths to create a local vortex in the channel fluid passage that stalls the back flow in the channel fluid passage.