Abstract: A liquid ejection head includes: an ejection element configured to generate a pressure for ejecting the liquid; a supply channel through which the liquid is supplied to a pressure chamber; a collection channel connected to the supply channel through the pressure chamber and through which the liquid is collected from the pressure chamber; a circulation pump capable of supplying the liquid from the supply channel into the pressure chamber, and collecting the liquid in the pressure chamber through the collection channel and sending the liquid to the supply channel; a first pressure adjustment unit disposed between an outlet channel of the circulation pump and the supply channel and configured to adjust a pressure in the supply channel; and a second pressure adjustment unit disposed between an inlet channel of the circulation pump and the collection channel and configured to adjust a pressure in the collection channel.

Abstract: A liquid ejection head includes: an ejection element configured to generate a pressure for ejecting the liquid; a supply channel through which the liquid is supplied to a pressure chamber; a collection channel connected to the supply channel through the pressure chamber and through which the liquid is collected from the pressure chamber; a circulation pump capable of supplying the liquid from the supply channel into the pressure chamber, and collecting the liquid in the pressure chamber through the collection channel and sending the liquid to the supply channel; a first pressure adjustment unit disposed between an outlet channel of the circulation pump and the supply channel and configured to adjust a pressure in the supply channel; and a second pressure adjustment unit disposed between an inlet channel of the circulation pump and the collection channel and configured to adjust a pressure in the collection channel.

Abstract: In an ink jet printing method for discharging ink from a liquid discharge head, the ink contains titanium oxide having a precipitation velocity of 1.0×10?11 m/s or more based on a Stokes equation in the ink, the liquid discharge head comprises a discharge port, a pressure chamber, an energy-generating element, an upstream flow channel for supplying a liquid to the pressure chamber, a downstream flow channel communicating with the pressure chamber, and a pump communicating with the upstream flow channel and the downstream flow channel and forming a circulation path in which the ink circulates in an order of the upstream flow channel, pressure chamber, downstream flow channel, and upstream flow channel, the liquid discharge head is configured so as to perform reciprocal scan, and a scanning velocity in a region where the liquid discharge head scans at a constant velocity is higher than the precipitation velocity.

Abstract: A relation of VV<V2 is satisfied, where VV is a volume of fluid passing a communication port of a first pressure control chamber of a first pressure adjustment unit and a fourth passage communicating with a circulating pump and the first pressure control chamber, in a direction from the first pressure control chamber toward the fourth passage in a period from a time when operation of the circulating pump is stopped to a time when pressure in the first pressure control chamber and pressure in the second pressure control chamber become equal to each other, and V2 is a volume of the fourth passage.

Abstract: In an ink jet printing method for discharging ink from a liquid discharge head, the ink contains titanium oxide having a precipitation velocity of 1.0×10?11 m/s or more based on a Stokes equation in the ink, the liquid discharge head comprises a discharge port, a pressure chamber, an energy-generating element for discharging the ink, an upstream flow channel for supplying a liquid to the pressure chamber, a downstream flow channel communicating with the pressure chamber, and a pump communicating with the upstream and downstream flow channels and forming a circulation path in which the ink circulates in an order of the upstream flow channel, pressure chamber, downstream flow channel, and upstream flow channel, and a ratio of the flow rate Q of the ink in the circulation path to the maximum cross-sectional area S of the circulation path, Q/S [m/s], is higher than the precipitation velocity.

Abstract: A liquid container includes a liquid containing portion configured to contain liquid, an outlet portion including an outlet port configured to discharge therethrough the liquid contained in the liquid containing portion, and a protection portion configured to cover the outlet port of the outlet portion. The protection portion has a first opening portion located above the outlet port. Where a diameter of the opening portion is defined as D, and a distance between the outlet port of the outlet portion and the opening portion in a vertical direction is defined as L, inequality (1) is satisfied.

Abstract: A cover member configured to be removable from a liquid container. The cover member includes a resin having a haze value of 14% or more and 96% or less. A thickness of a top surface of the cover member is 3.0 mm or less. A maximum height roughness Rz of the top surface of the cover member is 50 ?m or less. When a back surface of the top surface of the cover member is defined as a first surface and a surface of the protection portion facing the first surface is defined as a second surface, an L? value of the second surface in Commission Internationale de l'Eclairage (CIE) L?a*b*color space is 5 or more and 35 or less. A shortest distance between the first surface and the second surface is 0.4 mm or more and 2.0 mm or less.

Abstract: A valve unit includes a valve including (i) a body portion to be contained in a first chamber and (ii) a penetrating portion having an outer diameter smaller than an inner diameter of a through hole and provided in the body portion to penetrate through the through hole and extend to the inside of a second chamber. The valve is movable between an open position where a flow of a liquid through the through hole can be allowed and a restricted position where a flow of the liquid through the through hole can be restricted. When La is a width of a gap between an outer peripheral surface of the penetrating portion and an inner wall surface of the through hole and Lb is a width of a gap between an outer peripheral surface of the body portion and an inner wall surface of the first chamber, La?1.2×Lb is satisfied.

Abstract: Provided are a liquid ejection head and a liquid ejection apparatus that can suppress reduction of the ejection stability. To this end, an opening of a circulation pump connected with a supply port is positioned higher than a discharge port in a vertical direction in a usage orientation of the liquid ejection head, and the discharge port is positioned higher than the supply port in the vertical direction or at the same height as that of the supply port in the vertical direction in the usage orientation of the liquid ejection head.

Abstract: A liquid ejection head includes: an ejection element configured to generate a pressure for ejecting the liquid; a supply channel through which the liquid is supplied to a pressure chamber; a collection channel connected to the supply channel through the pressure chamber and through which the liquid is collected from the pressure chamber; a circulation pump capable of supplying the liquid from the supply channel into the pressure chamber, and collecting the liquid in the pressure chamber through the collection channel and sending the liquid to the supply channel; a first pressure adjustment unit disposed between an outlet channel of the circulation pump and the supply channel and configured to adjust a pressure in the supply channel; and a second pressure adjustment unit disposed between an inlet channel of the circulation pump and the collection channel and configured to adjust a pressure in the collection channel.

Abstract: A liquid storage bottle includes a bottle body having a resin-made first cylindrical part at one end, the first cylindrical part having an opening at its front end, and a tubular nozzle for pouring out the liquid contained in the inside of the bottle body by way of the opening, the tubular nozzle having a resin-made second cylindrical part bonded to the bottle body. The inner peripheral surface of the second cylindrical part is welded to the outer peripheral surface of the first cylindrical part. The outer peripheral surface of the first cylindrical part is provided with an annular groove extending in the circumferential direction and the annular groove is made to contain a part of the resin that is molten during the bonding operation.

Abstract: A liquid storage bottle includes a bottle main body having a first cylindrical portion formed of a resin and a nozzle and has a second cylindrical portion formed of a resin and welded to the first cylindrical portion on an outer peripheral side of the first cylindrical portion. The first cylindrical portion includes an outer peripheral surface and a first annular surface extending radially outward from an axial end portion of the outer peripheral surface, the second cylindrical portion includes an inner peripheral surface facing the outer peripheral surface of the first cylindrical portion and a second annular surface which extends radially outward from an axial end portion of the inner peripheral surface and faces the first annular surface of the first cylindrical portion, and a peripheral wall portion extending in an axial direction is formed radially outside the second annular surfaces.

Abstract: A liquid storage bottle includes a nozzle which has an inlet through which a liquid is injected, a cylindrical cap which is mountable on the nozzle to open or close the inlet, a slit valve which is provided in the inlet and includes a plurality of slits intersecting each other, and a sealing unit which seals the inlet when the cap is mounted on the nozzle. The cap includes a protrusion which protrudes from a surface facing the inlet toward the slit valve when the cap is mounted on the nozzle, and a tip portion of the protrusion faces the slit valve at a position separated in a radial direction of the nozzle from an intersection of the plurality of slits in a state where the inlet is sealed by the sealing unit.

Abstract: A liquid storage bottle includes a bottle main body, a nozzle having a discharge port through which a liquid stored in the bottle main body is discharged, a cap mountable on the nozzle and a sealing unit sealing the discharge port when the cap is mounted on the nozzle. The sealing unit includes an annular first rib, an annular second rib and an annular third rib. The outer peripheral surface of the first rib is inclined with respect to the axial direction of the nozzle so that a diameter decreases toward a tip portion of the first rib and the inner peripheral surface of the third rib is inclined with respect to the axial direction of the cap so that a diameter increases toward a tip portion of the third rib.