There is provided a liquid discharge apparatus configured to discharge a liquid, including a channel member for the liquid. The channel member is formed to include: individual channels; a first and second manifold channels; and a bypass channel. Each of the individual channels and the bypass channel are all connected to the first manifold channel on only one of an upper and lower sides of a central portion between upper and lower surfaces of the first manifold channel, and connected to the second manifold channel on only one of upper and lower sides of a central portion between upper and lower surfaces of the second manifold channel. A channel resistance of the bypass channel is smaller than that of the individual channels.

A channel member of a liquid ejection head includes an ejection surface, an outer peripheral surface that is connected to an outer edge of the ejection surface and that faces outside of the ejection surface in a direction along the ejection surface, and a plurality of ejection holes that open in the ejection surface. The channel member includes a plurality of concave portions in the outer edge of the ejection surface, the plurality of concave portions being recessed in the ejection surface and being recessed in the outer peripheral surface. With the configuration, it is possible to collect, in the concave portions, a liquid (such as ink mist) that has leaked out from the ejection holes.

A piezoelectric ceramic composition is represented by a composition formula A.sub.xBO.sub.3 and includes potassium sodium niobate containing K and Na that account for 80% or more of an amount of A-site elements and containing Nb that accounts for 70% or more of an amount of B-site elements. The piezoelectric ceramic composition contains Ta and Fe at a B-site.

There is provided a liquid discharge head including: a plurality of first individual channels; a first supply manifold; a first return manifold; a plurality of second individual channels; a second supply manifold; a second return manifold; and a first bypass channel communicating the first supply manifold and the second return manifold. The first bypass channel includes: a first supply connecting channel, a first return connecting channel, and a first connecting channel. Channel resistance in one of the first supply connecting channel and the first return connecting channel is greater than channel resistance in the first connecting channel.

A liquid discharge head includes a channel unit. The channel unit is formed therein with: a plurality of individual channels aligning in a first direction, a common channel extending in the first direction, a supply hole in communication with the common channel, and a damper chamber provided in a position overlapping with the supply hole in a second direction orthogonal to the first direction. The channel unit includes a first plate having a first surface where a recess is formed to constitute the damper chamber, and a second plate having a second surface attached to the first surface via an adhesive. A protrusion is provided on a bottom of such a first part of the recess as overlaps with the supply hole in the second direction.

A liquid discharge head according to an embodiment includes a head body having a first surface configured to discharge a liquid and a second surface facing the first surface, a drive IC configured to drive the head body, and a head cover configured to cover at least the second surface of the head body while housing the drive IC. The head cover includes a top plate facing the second surface of the head body and a first side plate that is connected to the top plate and that is in contact with the drive IC, and in the head cover, a thickness of the first side plate is thinner than a thickness of the top plate.

A printhead module includes a plurality of rows of printhead nozzles, at least some of the rows including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed, wherein the displaced row portions of at least some of the rows are different in length than the displaced row portions of at least some of the other rows.

A liquid discharge head includes a head body, a driver IC, a housing, a heat dissipation plate, and a pressing member. The head body includes a discharge hole configured to discharge a liquid. The driver IC controls driving of the head body. The housing is located on the head body, and includes an opening at a side surface. The heat dissipation plate is located at the opening of the housing, and is configured to dissipate heat generated by the driver IC. The pressing member presses the driver IC against the heat dissipation plate. In addition, the heat dissipation plate is fixed to the pressing member.

An inkjet head including a flow path unit and a plurality of actuator units, each of the plurality of actuator units has a parallelogram shape defined by two sets of opposing sides, which is substantially parallel to a first direction and a second direction intersecting with each other along a plane, the side of the actuator unit parallel to the second direction is substantially parallel to that of an adjacent actuator unit and is shifted from that of the adjacent actuator unit in the second direction, the plurality of actuator units are inclined with respect to two contour lines of a flow path unit, the two contour lines being parallel with each other and extending in a longitudinal direction of the flow path unit, and centers of gravity of contours of the plurality of actuator units are arranged on substantially one straight line which is parallel to the contour lines.

A liquid discharge head includes a flow channel member including a first surface and a second surface opposite to the first surface, and a pressing unit on the first surface. The flow channel member includes a first discharge hole and a second discharge hole in the second surface, a first individual flow channel connected to the first discharge hole, a first pressurizing chamber on an upstream side of the first discharge hole in the first individual flow channel, a second individual flow channel connected to the second discharge hole, a second pressurizing chamber on an upstream side of the second discharge hole in the second individual flow channel, and a manifold commonly connected to an upstream side of first individual flow channel and an upstream side of the second individual flow channel. The first individual flow channel and the second individual flow channel have an overlapping portion in plan view.