A fluid circulation and ejection system may include a microfluidic die, a single orifice fluid ejector having a drive chamber in the microfluidic die and a pressurized fluid source remote from the microfluidic die to create a pressure gradient across the drive chamber to circulate fluid across the drive chamber.

A fluid circulation and ejection system may include a microfluidic die, a single orifice fluid ejector having a drive chamber in the microfluidic die and a pressurized fluid source remote from the microfluidic die to create a pressure gradient across the drive chamber to circulate fluid across the drive chamber.

An inkjet printer configured to control the temperature of ink discharged from nozzles of an inkjet head is proposed. The inkjet printer includes: an inkjet head including a plurality of nozzles configured to discharge ink, an ink reservoir configured to store ink supplied to the inkjet head, a supply channel configured to supply the ink in the ink reservoir to the inkjet head, a pressure control device connected to the ink reservoir through a pressure control tube and configured to maintain the meniscus of the ink injected into the inkjet head, and the ink temperature control unit configured to control temperature of the ink discharged from the inkjet head.

A liquid ejection head with which print of good print quality can be obtained and a method of manufacturing the liquid ejection head are provided. For that purpose, warped flow path members are joined to each other as flow path members used for a print head to form a flow path member warped in a direction opposite to a direction of warpage due to a temperature rise during printing.

An example printing fluid circulation circuit for a printing system comprises a first circuit port to supply printing fluid to, or receive printing fluid from, a first fluid port of a printhead and a second circuit port to supply printing fluid to, or receive printing fluid from, a second fluid port of a printhead. The printing fluid circulation circuit is to operate in a first mode to concurrently supply printing fluid from the first reservoir to the first circuit port and from the second circuit port to a second reservoir, and in a second mode to concurrently supply printing fluid from the first reservoir to the second circuit port and from the first circuit port to the second reservoir.

An example printing fluid circulation circuit for a printing system comprises a first circuit port to supply printing fluid to, or receive printing fluid from, a first fluid port of a printhead and a second circuit port to supply printing fluid to, or receive printing fluid from, a second fluid port of a printhead. The printing fluid circulation circuit is to operate in a first mode to concurrently supply printing fluid from the first reservoir to the first circuit port and from the second circuit port to a second reservoir, and in a second mode to concurrently supply printing fluid from the first reservoir to the second circuit port and from the first circuit port to the second reservoir.

An inkjet printing system includes: (a) an inkjet printhead having a rigid elongate manifold with first and second parallel ink supply channels extending along a length of the manifold between respective ink ports positioned at opposite ends thereof; and a plurality of printhead chips mounted to a lower surface of the manifold, the ink supply channels supplying ink to the printhead chips via ink outlets defined in the lower surface. One end of the manifold has a first ink inlet port for the first ink supply channel and an ink outlet port for the second ink supply channel. The other end of the manifold has a first ink outlet port for the first ink supply channel and a second ink inlet port for the second ink supply channel. An ink delivery system is configured to flow ink along the first and second channels in opposite directions.

A liquid ejection head includes a recording element substrate having a substrate provided with a plurality of flow paths for liquid to be ejected on a recording material by a recording element and a cover member that is provided with a plurality of communication holes in communication with the plurality of flow paths and that is joined to the substrate, a liquid supply member supplying the liquid to the plurality of flow paths through the plurality of communication holes of the cover member, and an adhesive member adhering the cover member and the liquid supply member. At least a part of an abutment region of the cover member in abutment against the substrate and apart from a region provided with the plurality of communication holes has a cover member opening for contacting the adhesive member and the substrate to each other.

A head cooling device includes a refrigerant supplying portion, a switching portion, and a switch processing portion. The refrigerant supplying portion supplies a refrigerant to each of a plurality of recording heads, which ejects ink, through a supplying path. The switching portion can switch a corresponding supplying path of at least one of the plurality of recording heads. The switch processing portion controls the switching portion to switch the corresponding supplying path so as to decrease the temperature difference among the plurality of recording heads.

A printing apparatus comprises: a print head comprising, for each of a plurality of types of inks, an ejection opening and pressure chamber, and configured to perform printing operation by ejecting the ink from the ejection opening; a circulation unit capable of circulating the ink of each ink type; a determination unit configured to determine an accumulated time for which a first type of ink is circulated by the circulation unit in the printing operation using the first type of ink and not using a second type of ink different from the first type of ink; and a control unit configured to perform control based on the determined accumulated time to cause the circulation unit to circulate at least the second type of ink among the plurality of types of inks in a case where the accumulated time is longer than a predetermined time.