Hewlett-packard Development Company, L.p.

Si-Lam J Choy

Michael W Cumbie

Garrett E Clark

James Richard Przybyla

Richard W Seaver

Frank D Derryberry

Chien-Hua Chen

Alexander N Govyadinov

David N Olsen

Ronald Albert Askeland

Erik D Torniainen

Galen P Cook

Justin M Roman

Paul Mark Haines

Daniel D Dowell

Brett E Dahlgren

Jeffrey R Pollard

Ronald J Ender

Jeremy Sells

Craig L Malik

Tsuyoshi Yamashita

Blair A Butler

Hilary Ely

Jacob Lum

Seth Stephen Haddix

Jacob M Lum

Galen Cook

A fluid ejection die may include a fluid actuator, a substrate supporting the fluid actuator, a chamber layer supported by the substrate and a bypass passage in the substrate. The substrate may include a closed inlet channel having an inlet opening for connection to an outlet of a fluid source and an outlet channel having an outlet opening of a first size for connection to an inlet of the fluid source. The chamber layer includes a recirculation passage to supply fluid for ejection by the fluid actuator through an ejection orifice and to circulate fluid across the fluid actuator from the closed inlet channel to the outlet channel. The bypass passage is of a second size less than the first size and connects the inlet channel to the inlet of the fluid source while bypassing any fluid actuator provided for ejecting fluid through an ejection orifice.

Recirculation bypass

In various examples, a printbar is formed from multiple modular fluid ejection subassemblies joined together through a molding process that provides for a continuous planar substrate surface. A mold may secure the modular fluid ejection subassemblies during a molding process in which a runner conveys a molding material to seams between the joined modular fluid ejection subassemblies.

Coplanar modular printbars

A metered volume microfluidic device can include fluid flow microfluidics. The fluid flow microfluidics can include an inflow channel, a metered volume chamber positioned to receive working fluid from the inflow channel, a metered volume outflow channel positioned to receive and direct a metered volume of the working fluid when discharged from the metered volume chamber, and a capillary check valve. The capillary check valve can allow excess working fluid to exit the metered volume chamber when filling the metered volume chamber via the inflow channel. The capillary check valve can also prevent excess working fluid that has passed there through from being reintroduced into the metered volume chamber when the working fluid is discharged into the metered volume outflow channel.

Metered volume microfluidic devices

In some examples, a fluid ejection die includes a plurality of nozzles arranged in a plurality of nozzle columns, the plurality of nozzle columns distributed across a width of the fluid ejection die in a staggered manner, wherein nozzles of each respective nozzle column of the plurality of nozzle columns are spaced apart along a length of the fluid ejection die, wherein the plurality of nozzle columns includes a first pair of neighboring nozzle columns that are spaced by a first distance across the width. The plurality of nozzle columns includes a second pair of neighboring nozzle columns that are spaced by a second distance across the width, the second distance being larger than the first distance.

Nozzle arrangements

A printing fluid pen includes a plurality of fluid ports, a pressure regulator in fluid communication with a first fluid port, and a valve in fluid communication with a second fluid port. The first fluid port is to deliver printing fluid to a fluid ejection device, and the second fluid port is to direct printing fluid out of the pen. In response to negative pressure, the valve is to open to enable fluids within the pen to exit via the second port.

Printing fluid circulation

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Corvallis, OR, United States of America

Si-Lam J Choy