Fluid ejection devices with multiple activation modes are disclosed. An example printhead assembly includes a fluid ejection nozzle, a first resistor fluidically coupled to the fluid ejection nozzle, and a second resistor fluidically coupled to the fluid ejection nozzle. The example printhead also includes an addressing circuit to receive a nozzle address and an activation mode to activate the fluid ejection nozzle. The activation mode determines which of the first resistor and the second resistor are to be energized.

A microfluidic die is disclosed that includes a plurality of heaters above a substrate, a plurality of chambers and nozzles above the heaters, a plurality of first contacts coupled to the heaters, and a plurality of second contacts coupled to the heaters. The plurality of second contacts are coupled to each other and coupled to ground. The die includes a plurality of contact pads, a first signal line coupled to the plurality of second contacts and to a first one of the plurality of contact pads, and a plurality of second signal lines, each second signal line being coupled to one of the plurality of first contacts, groups of the second signal lines being coupled together to drive a group of the plurality of heaters with a single signal, each group of the second signal lines being coupled to a remaining one of the plurality of contact pads.

Influence of transform of quality to an entire liquid discharge head is suppressed when a heat resistor and a covering portion are electrically connected to each other. To address this problem, a liquid discharge head substrate includes fuse portions for respective heat resistor arrays.

A print element substrate and a liquid ejection head capable of suppressing degradation of a print quality caused by a white stripe/black stripe etc., is actualized without using a high degree of microfabrication technology. As a result of asymmetric deformation by swelling in a direction of relative movement to a print medium, print elements having different liquid droplet ejection directions are made to coexist and arrayed for that purpose.

A fluid ejection device includes a fluid slot, a fluid ejection chamber communicated with the fluid slot, a drop ejecting element within the fluid ejection chamber, a fluid circulation channel communicated at one end with the fluid slot and communicated at another end with the fluid ejection chamber, a fluid circulating element within the fluid circulation channel, and a channel wall separating the fluid ejection chamber and the fluid circulation channel. The fluid circulation channel includes a channel loop, and a width of the channel wall is based on a width of the channel loop and a width of the fluid ejection chamber.

A liquid discharging head includes a discharge port that discharges a liquid, a pressure chamber that communicates with the discharge port, and an energy generating element that is disposed in the pressure chamber. In the liquid discharging head, the discharge port is provided with a plurality of projections that project towards a central portion of the discharge port from an inner peripheral edge of the discharge port, and an interval between the projections at a location where the projections are closest to each other is 5 m or less.

A fluid ejection device includes a fluid slot, a first fluid ejection chamber communicated with the fluid slot and including a first drop ejecting element, a second fluid ejection chamber communicated with the fluid slot and including a second drop ejecting element, a fluid circulation path communicated with the first fluid ejection chamber and the second fluid ejection chamber, and a fluid circulating element within the fluid circulation path.

In a liquid ejection head, an ejection unit of a channel member includes an ejection hole, a pressurizing chamber connected to the ejection hole, a first channel and a second channel each connecting the pressurizing chamber and a first common channel, and a third channel connecting the pressurizing chamber and a second common channel. The first common channel, in the channel direction, includes a plurality of first portions, and a plurality of second portions each located between each two of the plurality of first portions and having smaller cross-sectional areas than those of the first portions in front and back of the same. In each of the plurality of ejection units, the first channel and the second channel are individually connected to two positions in the first common channel which sandwich at least one of the second portions between them.

A recording element substrate includes: a plurality of discharging ports; a plurality of nozzles connected to the plurality of discharging ports respectively; a passage forming portion in which a plurality of individual passages connected to the plurality of nozzles respectively and a common passage connected to the plurality of individual passages are formed; a plurality of supply ports disposed at positions corresponding to a plurality of nozzle groups on the common passage respectively along an array direction of the plurality of discharging ports; and a plurality of supply passages which extend from the plurality of supply ports to a rear surface of the recording element substrate in a direction intersecting with the rear surface. A plurality of heaters configured to heat liquid flowing through the common passage are provided for each of the plurality of supply ports along at least a part of a peripheral edge of the supply port.

According to an example, a fluid ejection device may include a fluid feed slot, a plurality of fluid ejection chambers in fluid communication with the fluid feed slot, a plurality of drop ejecting elements, in which a drop ejecting element of the plurality of drop ejecting elements is positioned within each of the plurality of fluid ejection chambers, a fluid circulation channel in fluid communication at a first end of the fluid circulation channel with the fluid feed slot and in fluid communication at multiple second ends of the fluid circulation channel with the plurality of fluid ejection chambers, and a fluid circulating element within the fluid circulation channel. The fluid ejection device may also include a bubble dissipating structure positioned within the fluid circulation channel outside of the plurality of fluid ejection chambers.