There is provided a liquid ejecting head which is long in a first direction and short in a second direction, including: a first introduction section; a second introduction section; a first filter chamber group having a first filter chamber and a second filter chamber; a second filter chamber group having a third filter chamber and a fourth filter chamber; a first supply flow path for supplying the liquid from the first introduction section to the first filter chamber group; and a second supply flow path for supplying the liquid from the second introduction section to the second filter chamber group, in which the first introduction section, the second introduction section, the first filter chamber group, and the second filter chamber group are arranged side by side in this order in the first direction.

A cover member includes two end regions located at two ends in a first direction, and two beam portions which extend in the first direction and connect the two end regions together and which, together with the two end regions, form a single opening that exposes a plurality of discharge ports. When a width of the opening is denoted as a [mm], a minimum length in the first direction of the end regions is denoted as c [mm], a modulus of longitudinal elasticity of the cover member is denoted as E [GPa], and a thickness of the cover member is denoted as t [mm], the following expression is established.

[00001]$c\ge \frac{10.Math.{\left(\frac{a}{25}\right)}^4}{{\left(\frac{t}{0.3}\right)}^3.Math.\left(\frac{E}{200}\right)}$

A head includes the passageway member which is configured by a plurality of plates stacked through the adhesive and in which the ink passageways are configured by communication of the through holes individually formed in the plurality of plates to each other. The plurality of plates includes the resin plate and a plurality of metal plates. The resin plate does not have a relief groove for the adhesive. The plurality of metal plates include the eighth metal plate and/or ninth metal plate which is adhered to the resin plate and includes the relief groove for the adhesive on the resin plate side.

A liquid discharge head including a first recording element substrate, a second recording element substrate, and a third recording element substrate successively arranged in a longer direction of the liquid discharge head, the first, second, and third recording element substrates each including a discharge port configured to discharge a liquid and an energy-generating element configured to generate energy used for discharging the liquid; a first support member supporting an end part of the first recording element substrate on a side of the second recording element substrate and an end part of the second recording element substrate on a side of the first recording element substrate; and a second support member supporting an end part of the second recording element substrate on a side of the third recording element substrate and an end part of the third recording element substrate on a side of the second recording element substrate.

An ink jet apparatus includes: a head that discharges liquid; a circuit substrate that has a drive circuit for driving the head; a heat sink which has a part that is in direct or indirect contact with the circuit substrate and is able to dissipate heat generated in the circuit substrate; and a fan that generates air flow capable of cooling the heat sink. The heat sink is configured such that the air flow is not directly blown against the drive circuit and such that the air flow having changed a direction after blown against the heat sink is not blown against the drive circuit.

A print head assembly comprises a print head unit, a cooling duct, and a blower arranged to pass a gaseous cooling medium through the cooling duct.

The cooling duct has an elongated closed hollow cross-section bounded on at least one side by a flat wall. The print head unit is attached to the flat wall outside of the cooling duct such that the print head unit is cooled by the gaseous medium passing through the cooling duct via thermal contact through the flat wall of the cooling duct.

A liquid ejection head includes a support member extending in a first direction, a print element board having an ejection port through which liquid is ejected, and first and second members arranged in the support member adjacent to each other along the first direction, each having a supply path extending in the first direction. The print element board element generates energy used for ejection of the supply paths supplied liquid. The first member includes an outlet port through which the supplied liquid flows out. The second member includes an inlet port through which the liquid from the outlet port flows. The outlet port is provided near a first member supply path end portion on the support member side on which the second member is provided. The inlet port is provided near a second member supply path end portion on the support member side on which the first member is provided.

A liquid ejecting head unit includes an ejecting surface in which nozzles for ejecting a liquid are formed, and a first and a second circuit substrates for ejecting the liquid from the nozzles, in which a planar shape of the ejecting surface includes a first, a second and a third portions. A center line parallel to a long side of a rectangle of a minimum area surrounding the ejecting surface passes the first portion but not the second and third portions. The second and third portions are arranged adjacently to the first portion interposed therebetween. The first circuit substrate is positioned in the first and second portions. The second circuit substrate is positioned in at least one of the first and third portions.

A liquid ejecting head unit that ejects a liquid from a nozzle, the liquid ejecting head unit including a driving portion that includes an ejection surface on which a plurality of nozzles that eject the liquid are formed; a fixing plate to which a plurality of the driving portions are fixed, and a holder that (Condition 1) is fixed to a support body, which supports the liquid ejecting head unit, and the holder has a conductive property that electrically connects the support body and the fixing plate to one another, or that (Condition 2) includes a portion that projects from the fixing plate in a direction orthogonal to the ejection surface, and houses the plurality of driving portions.

A liquid discharging head includes a support member and plural print element substrates through which a liquid is discharged. The print element substrates are disposed on the support member and provided with the liquid through a liquid supply channel formed in the support member. The sectional area of the liquid supply channel at a position corresponding to each of the print element substrates is determined in accordance with an order in which the print element substrates are provided with the liquid.