A liquid discharge head includes a recording element configured to generate thermal energy and a discharge orifice disposed at a position facing the recording element. A bubble is generated in liquid by the thermal energy, liquid between the bubble and the discharge orifice is discharged from the discharge orifice by the pressure of the generated bubble, and the bubble communicates with the atmosphere on the outside of the discharge orifice.

Provided is a liquid ejection head and a liquid ejection apparatus capable of efficiently ejecting a liquid having a viscosity of 2.5 cp or above at high frequency. To this end, a relation L?H?0.4D is satisfied, where D is the thickness of an ejection port plate, H is the distance from an electrothermal conversion element to the outermost surface of the ejection port plate, and L is the height of an air bubble.

An inkjet head includes a head chip and an ink chamber. The head chip has a nozzle substrate provided with nozzles which discharge ink. The ink chamber is located over the head chip. In the ink chamber, the ink to be supplied to the nozzles is stored. The inkjet head is mounted on a mounting member. Between the nozzle substrate and the ink chamber, the inkjet head has a position reference substrate provided with butting parts. The butting parts are butted against the mounting member to position the inkjet head when the inkjet head is mounted on the mounting member.

Disclosed is a liquid discharge method of discharging liquid with a liquid discharge head having a heating surface that contacts and heats the liquid and a discharge port that faces the heating surface and discharges the liquid. The method includes heating the liquid through the heating surface to generate a bubble such that the bubble communicates with an atmosphere, thereby discharging the liquid. The liquid that is being discharged from the discharge port includes a trailing portion. The trailing portion moves toward the heating surface in response to a reduction in volume of the bubble and contacts the heating surface. The method further includes heating the trailing portion through the heating surface while the trailing portion is in contact with the heating surface, thereby generating a bubble.

A printing apparatus includes an ink treatment chamber having an inlet for receiving ink into the chamber. The ink is received in a non-gaseous statement. Heating elements heat the ink in the ink treatment chamber. After being heated, a nozzle ejects the heated ink. The heating of the ink may cause the ink to be changed to a gaseous ink and the gaseous ink may be ejected by the nozzle.

A liquid ejection head in which, upon heating performed by a heating element, a bubble is formed in a liquid retained in a bubble forming chamber, the liquid is ejected, and the bubble disappears without any atmospheric communication. When a length L is a length of the heating element in a liquid supply direction, when viewing in a liquid ejection direction, a position of a center of gravity of an ejection port is spaced apart from a position of a center of gravity of the heating element by L/3.5 or more in the liquid ejection direction, and when a length of an ejecting portion in the liquid ejection direction is l and a length of the bubble forming chamber in the liquid ejection direction is h, l/h is 2 or smaller.

There is provided a head module including: a case; and a head provided with nozzles through which a liquid is jetted. The head includes: two first inlets through which the liquid flows into the head; and a first outlet through which the liquid flows out of the head. The case includes: a second inlet through which the liquid supplied from an outside flows into the case; two inflow-connecting ports communicating with the second inlet and connected to the two first inlets; an outflow-connecting port connected to the first outlet; and a second outlet communicating with the outflow-connecting port and through which the liquid flows out to the outside.

A liquid discharge head includes a recording element configured to generate thermal energy and a discharge orifice disposed at a position facing the recording element. A bubble is generated in liquid by the thermal energy, liquid between the bubble and the discharge orifice is discharged from the discharge orifice by the pressure of the generated bubble, and the bubble communicates with the atmosphere on the outside of the discharge orifice.

A liquid ejection head in which, upon heating performed by a heating element, a bubble is formed in a liquid retained in a bubble forming chamber, the liquid is ejected, and the bubble disappears without any atmospheric communication. When a length L is a length of the heating element in a liquid supply direction, when viewing in a liquid ejection direction, a position of a center of gravity of an ejection port is spaced apart from a position of a center of gravity of the heating element by L/3.5 or more in the liquid ejection direction, and when a length of an ejecting portion in the liquid ejection direction is l and a length of the bubble forming chamber in the liquid ejection direction is h, l/h is 2 or smaller.

In one embodiment, a printhead includes a substrate comprising a single fluid slot with sidewall surfaces. The printhead also includes a plurality of fluid chambers in fluid communication with the fluid slot. The printhead includes a membrane disposed between the fluid slot and the fluid chambers. The membrane comprises membrane side surfaces that form fluid feed holes to provide the fluid communication between the fluid slot and the fluid chambers. A protective coating is disposed on each of the surfaces.