Hewlett-packard Development Company, L.P.

Jason Oak

Alexander N Govyadinov

Brian M Taff

Michael B Hager

A fluid ejection assembly includes a fluid slot, a recirculation channel, and a drop ejection element within the recirculation channel. A pump element is configured to pump fluid to and from the fluid slot through the recirculation channel. A first addressable drive circuit associated with the drop ejection element and a second addressable drive circuit associated with the pump element are capable of driving the drop ejection element and the pump element simultaneously.

Fluid ejection assembly with circulation pump

In an embodiment, a fluid ejection device includes a substrate with a fluid slot, and a chamber layer over the substrate that defines a firing chamber and a fluidic channel extending through the firing chamber and in fluid communication with the slot at first and second ends. The device includes a tophat layer formed as a two-layer stack over the chamber layer, and a nozzle bore over the firing chamber that comprises a greater cavity formed in a first layer of the stack and a lesser cavity formed in a second layer of the stack, the greater cavity encompasses a larger volume than the lesser cavity.

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Corvallis, OR, United States of America

Jason Oak