A liquid discharge head includes a substrate, a pressure chamber through which a first liquid and a second liquid flow while being in contact with each other, a pressure generating element configured to pressurize the first liquid, and a discharge port configured to discharge the second liquid. The substrate has a first channel and a second channel that each extend through the substrate. The first channel is used to supply the first liquid to the pressure chamber. The second channel is used to supply the second liquid to the pressure chamber. A viscosity of the second liquid is greater than a viscosity of the first liquid. An average cross-section area of the second channel is greater than an average cross-section area of the first channel.

A method of forming a print head, by forming a heater chip. Via zones having peripheries are defined on a substrate, with heaters formed along the entire peripheries of the via zones. Traces that electrically connect to each of the heaters are formed. In some embodiments, the heater chip is then stored for a period of time. After storing the heater chip, vias are formed in only a selected portion of the via zones, which is a subset of the via zones. A channel layer is formed on the heater chip by forming a first layer on the heater chip. Flow channels are formed in the first layer from the vias to only those heaters on the heater chip that are disposed along the selected portion of the via zones. Bubble chambers are formed in the first layer around only those heaters on the heater chip that are disposed along the selected portion of the via zones. A nozzle plate in formed on the channel layer by forming a second layer on the first layer, and forming nozzles in the second layer above only those heaters on the heater chip that are disposed along the selected portion of the via zones.

The control portion controls (i) a discharging operation of discharging the liquid from the plurality of nozzles by driving the plurality of energy generation elements and (ii) a pressurization operation of pressurizing the liquid from the individual flow path side in a state in which the plurality of nozzles are sealed by the sealing portion.

A pagewide printhead for printing redundantly in four colors. First and second rows of printhead chips are mounted on a common ink manifold having four ink supply channels for supplying four colors of ink to the first and second rows of printhead chips. Dedicated ink outlets interconnect one ink supply channel of the ink manifold with a pair of redundant nozzle rows in each printhead chip.

A liquid discharge head includes: a nozzle plate having a nozzle from which a liquid is to be discharged in a discharge direction, the nozzle having a cylindrical hole having periodical convex portions and concave portions on a sidewall of the nozzle in the discharge direction, a diameter of an outermost portion of the nozzle in the discharge direction being smaller than an average diameter of minimum values and maximum values of diameters of the cylindrical shape. The average diameter is obtained by: Average diameter = (Sum of minimum values + Sum of maximum values) / (Count of minimum values + Count of maximum values).

A highly reliable liquid ejection head comprises a substrate made of silicon and having a first surface and a second surface opposite to the first surface, an ejection port forming member bonded to the first surface of the substrate and formed with an ejection port for ejecting liquid, and a bonded member configured to be bonded to the second surface of the substrate. A through flow path is formed in the substrate, which is configured to pass through the substrate and to supply liquid to the ejection port. A first protective film made of a metal oxide is formed on an inner surface of the through flow path, and a second protective film made of a silicon compound is formed on all of the second surface of the substrate.

A liquid ejection module includes a pressure chamber, a supply flow channel that supplies a liquid to the pressure chamber, a collection flow channel that collects the liquid from the pressure chamber, a liquid feeding chamber connected to one of the supply flow channel and the collection flow channel, and a connection flow channel connecting the liquid feeding chamber to the other of the supply flow channel and the collection flow channel. The liquid feeding chamber includes a liquid feeding mechanism that circulates the liquid in the supply flow channel, the pressure chamber, the collection flow channel, the liquid feeding chamber, and the connection flow channel. A ratio of a sum of flow channel resistance of the supply flow channel, the pressure chamber, and the collection flow channel relative to flow channel resistance of the connection flow channel is equal to or above 0.5.

A liquid ejection head, a liquid ejection apparatus, and a liquid ejection method are capable of sufficiently suppressing the thickening of a liquid in an ejection orifice. The liquid ejection head includes a pressure chamber, a channel in which a liquid is caused to flow through the pressure chamber, an ejection orifice communicating with the pressure chamber, and an ejection energy generation element configured to eject the liquid in the pressure chamber from the ejection orifice. A meniscus of the liquid is formed at an end portion of the ejection orifice communicating with the pressure chamber.

A fluid ejection assembly may include a fluid ejection die comprising a back face and a front face through which fluid is ejected. The fluid ejection die may further include a fan-out fluid passages converging towards the back face of the fluid ejection die, the fan-out fluid passages comprising a first fan-out fluid passage and a second fan-out fluid passage and a recirculation channel extending within a polymeric material from the first fan-out fluid passage to the second fan-out fluid passage adjacent the back face of the fluid ejection die.

A thermal inkjet printing device includes a fluidic die having a thermal sensor and a processor coupled to the fluidic die. The processor is to receive temperature data from the thermal sensor and determine a flow rate of liquid printing agent through the fluidic die based on the temperature data and an operating parameter for the fluidic die.