A substrate includes a layer including a base material and an intermediate layer including a wiring layer, an element formed on a side of the intermediate layer, and configured to generate energy for discharging a liquid, an insulating layer covering the element and the layer against a liquid chamber, and a conductive layer formed on the insulating layer so as to cover the element against the liquid chamber. The substrate further includes an electric connecting portion configured to electrically connect the wiring layer and the element, a non-insulated portion formed on a side of the intermediate layer and configured to be covered by the insulating layer against the liquid chamber, and an opening portion formed in the insulating layer at a position. The non-insulated portion is connected to the conductive layer via the opening portion.

A liquid discharge head includes: a substrate, where a recording element is disposed; and a discharge orifice forming member, where a discharge orifice, facing the recording element, and configured to discharge the liquid, is formed. The liquid discharge head has a pressure chamber, a first liquid channel configured to supply liquid to the pressure chamber, and a second liquid channel configured to recover liquid from the pressure chamber. The substrate has a liquid supply channel connected to the first liquid channel to supply liquid to the first liquid channel, and a liquid recovery channel connected to the second liquid channel, to recover liquid from the second liquid channel. Pressure at an inlet portion of the liquid supply channel is higher than pressure at an outlet portion of the liquid recovery channel, and a flow velocity of liquid within the pressure chamber is 3 to 140 mm/s.

A fluidic die may include a fluid channel layer defining a number of fluid channels therein, a slot layer disposed on a side of the fluid channel layer, and a first fluid slot and a second fluid slot defined in the slot layer. At least one of the fluid channels fluidically couples the first fluid slot to the second fluid slot. The first fluid slot and the second fluid slot are defined in the slot layer along a length of the fluidic die.

A fluid propelling apparatus, including a plastic compound, a MEMS at least partially surrounded by the compound, and a heat sink next to the MEMS, to transfer heat away from the MEMS, wherein the heat sink is at least partly surrounded by the compound.

A liquid discharge head includes: a substrate, where a recording element is disposed; and a discharge orifice forming member, where a discharge orifice, facing the recording element, and configured to discharge the liquid, is formed. The liquid discharge head has a pressure chamber, a first liquid channel configured to supply liquid to the pressure chamber, and a second liquid channel configured to recover liquid from the pressure chamber. The substrate has a liquid supply channel connected to the first liquid channel to supply liquid to the first liquid channel, and a liquid recovery channel connected to the second liquid channel, to recover liquid from the second liquid channel. Pressure at an inlet portion of the liquid supply channel is higher than pressure at an outlet portion of the liquid recovery channel, and a flow velocity of liquid within the pressure chamber is 3 to 140 mm/s.

A liquid discharge head includes a substrate, pressure chambers, a pressure generating element, a discharge port, and a liquid channel. First and second communication supply channels and first and second communication collecting channels are formed in the substrate. A central axis of a first communication supply opening is located closer to the corresponding pressure chamber than a central axis of a first common supply opening, or a central axis of a second communication supply opening is located closer to the corresponding pressure chamber than a central axis of a second common supply opening, or a central axis of a first communication collecting opening is located closer to the corresponding pressure chamber than a central axis of a first common collecting opening, or a central axis of a second communication collecting opening is located closer to the corresponding pressure chamber than a central axis of a second common collecting opening.

A fluid ejection device may include fluid actuators, ejection chambers adjacent the fluid actuators, nozzles extending from the ejection chambers, and fluid feed holes to supply fluid from a fluid supply passage to the ejection chambers. The fluid feed holes have ports connected to the ejection chambers. The ports are sized to pass bubbles formed by the fluid actuators out of the ejection chambers.

A fluid ejection apparatus executes a cleaning process and an ejection operation of ejecting fluid from ejection ports while causing the fluid to flow from a supply port to a fluid collection port of a flow channel provided in a fluid ejection head. Moreover, the fluid ejection apparatus adjusts a flow rate of the fluid flowing in the flow channel to a first flow rate during the ejection operation and adjusts the flow rate of the fluid flowing in the flow channel to a second flow rate higher than the first flow rate at least during the cleaning process.

An object is to provide a liquid ejection apparatus and a method of controlling a liquid ejection apparatus capable of preventing bubbles generated by kogation removal from interfering with the kogation removal. To this end, in a long liquid ejection head with a liquid circulated therethough, a pressure chamber is pressurized and a voltage is applied to a heat applying portion and an electrode to perform kogation removing cleaning.

A liquid discharge head includes an element substrate including a plurality of discharge ports configured to discharge liquid in a discharge direction onto a recording medium, and a heating element configured to heat the liquid, and a flow path member including a supply flow path configured to supply the liquid to the element substrate and a collection flow path configured to collect the liquid from the element substrate. The supply flow path and the collection flow path extend in a longitudinal direction of the flow path member and at least a part of the supply flow path and at least a part of the collection flow path overlap each other when being viewed in the direction parallel to the discharge direction.