There is provided a liquid discharge head including a channel unit. The channel unit includes: first and second individual channel groups including a plurality of first and second individual channels; two supply manifolds and two return manifolds; and bypass channels communicating with the two supply manifolds or with the two return manifolds. A relationship of |P1|>|P2| is satisfied, wherein P1 is a first pressure of the supply manifold provided commonly for the first individual channel group, P2 is a second pressure of the supply manifold provided commonly for the second individual channel group, −P1 is a third pressure of the return manifold provided commonly for the first individual channel group, and −P2 is a fourth pressure of the return manifold provided commonly for the second individual channel group.

A liquid ejecting head has a supply opening toward which a liquid is supplied, a collection opening through which the supplied liquid is collected, a nozzle that ejects the liquid supplied from the supply opening, and a filter disposed at an intermediate point in a flow path that couples the supply opening and the nozzle together. The liquid ejecting head further has a plurality of outlets leading from an upstream chamber disposed upstream of the filter to the collection opening.

A liquid ejection apparatus includes a liquid ejection head and a controller. The controller configured to perform: determining whether a discharge failure occurs in a first nozzle; in a case where it is determined that the discharge failure occurs in the first nozzle, determining whether a certain condition is satisfied; in a case where it is determined that the certain condition is satisfied: applying a flushing signal to a second driving element; applying a driving signal to the second driving element; determining whether the discharge failure occurs in a second nozzle; in a case where it is determined that the discharge failure does not occur in the second nozzle, executing a first purge; and in a case where it is determined that the discharge failure occurs in the second nozzle, executing a second purge.

A liquid discharging head includes a nozzle plate having a plurality of nozzles from which liquid is discharged; a plurality of individual liquid chambers that are communicably connected to the plurality of nozzles, respectively; a common liquid chamber that supplies liquid to the plurality of individual liquid chambers; and a circulation common liquid chamber that leads to a plurality of circulation channels. A part of the common liquid chamber overlaps the circulation common liquid chamber from a direction in which liquid is discharged from the nozzles, and another part of the common liquid chamber overlaps the circulation common liquid chamber from a direction orthogonal to both the direction in which liquid is discharged from the nozzles and a direction in which the nozzles are aligned.

A liquid discharge head includes a plurality of pressure chambers, a plurality of individual supply channels, a plurality of common supply channel branches, a common supply channel mainstream, a plurality of individual collection channels, a plurality of common collection channel branches, a common collection channel mainstream, a supply-side filter, and a bypass channel. The common supply channel mainstream is communicated with the common supply channel branches. The common collection channel mainstream is communicated with the common collection channel branches. The supply-side filter is in the common supply channel mainstream. The bypass channel bypasses the supply-side filter and communicates the common supply channel mainstream with the common collection channel mainstream. The bypass channel is connected to the common supply channel mainstream at a downstream of the supply-side filter in a direction of flow of the liquid along a longitudinal direction of the common supply channel mainstream.

A liquid discharge head includes: a channel member having a nozzle surface and a back surface disposed separately from the nozzle surface, the channel member formed having nozzles arranged in the nozzle surface, individual channels connected to the nozzles, first and second common channels connected to the individual channels, a first opening that is opened in the back surface and communicates with an end of the first common channel, and a second opening that is opened in the back surface and communicates with an end of the second common channel, and a filter member disposed on the back surface and having a filter that covers the first opening. The second opening is not covered with the filter, and an area of the first opening is larger than an area of the second opening.

An ink head includes: a common ink chamber; a first nozzle including a first nozzle hole, a first flow channel and the common ink chamber, and a first actuator; and a second nozzle including a second nozzle hole, a second flow channel and the common ink chamber, and a second actuator, the second nozzle being adjacent to the first nozzle in a first direction. The first flow channel is linked to the common ink chamber via a first opening. The second flow channel is linked to the common ink chamber via a second opening. A center position of the first opening is shifted from a center position of the second opening in at least a third direction, the third direction crossing the first direction when viewed along a second direction, the second direction being from the common ink chamber toward the first flow channel.

Systems, methods, and software for fabricating a printhead. In one embodiment, a method comprises punching first nozzle holes in a first nozzle plate with a first punch, where each of the first nozzle holes includes a first converging section. The method further comprises punching second nozzle holes in a second nozzle plate with a second punch, where each of the second nozzle holes includes a second converging section. The method further comprises bonding the first nozzle plate and the second nozzle plate to form a nozzle plate stack, where the first nozzle holes and the second nozzle holes define nozzles of the printhead.

A liquid ejection head includes an ejection opening; a passage in which an energy generation element is disposed; an ejection opening portion that allows communication between the ejection opening and the passage; a supply passage for allowing the liquid to flow into the passage; and an outflow passage for allowing the liquid to flow out to the outside. An expression of H.sup.−0.34×P.sup.−0.66×W>1.7 is satisfied when a height of the passage is set to H [μm], a length of the ejection opening portion is set to P [μm], and a length of the ejection opening portion is set to W [μm].

There is provided a liquid discharge head including: an individual channel member including individual channel rows; a first common channel member including first common channels and a first partitioning wall, and a damper joined to the first common channel member with adhesive. The damper has first portions that are elastically deformable and overlap with the first common channels and a second portion joined to the first partitioning wall and connected to the first portions. The second portion is thicker than the first portions.