There is provide a liquid discharge head including: a supply manifold; a feedback manifold; and a plurality of individual flow channels having: a supply portion, a descender portion, and a feedback portion. The supply manifold has a plurality of supply ports, and the feedback manifold has a plurality of feedback ports. At least part of the supply manifold overlaps with the feedback manifold in the second direction. The plurality of pressure chambers have first pressure chambers forming a first pressure chamber array and second pressure chambers forming a second pressure chamber array. The first pressure chamber array is arranged at one side, of the supply manifold, in a third direction and the second pressure chamber array is arranged at the other side, of the supply manifold, in the third direction. The first pressure chamber array and the second pressure chamber array are connected to the supply manifold.

A piezoelectric actuator is provided, including a vibration plate, a piezoelectric layer, a plurality of individual electrodes arranged in two arrays, first and second common electrodes which have first and second facing portions facing parts of the individual electrodes and first and second connecting portions connecting the first and second facing portions respectively, and first and second wiring portions which are arranged on the vibration plate and which are connected to the first and second common electrodes respectively via first and second connecting wirings, wherein one of the first connecting wirings connects the first connecting portion and one of the first wiring portion while striding over the second connecting portion.

A liquid ejection head includes a channel member, a pressurizing part, a cover member, and a sealing member. The channel member includes an ejection hole, a pressurizing chamber, an ejection hole surface, and a pressurizing chamber surface. The pressurizing chamber is connected with the ejection hole. The ejection hole surface is positioned on the ejection hole side. The pressurizing chamber surface is positioned on the pressurizing chamber side. The pressurizing part is positioned in a pressurizing region in the pressurizing chamber surface. The cover member stands on the channel member. The sealing member seals the cover member and the channel member. The channel member includes a groove positioned in the pressurizing chamber surface but outside the pressurizing region. The cover member is positioned in the groove. Further, the sealing member is positioned between a fixing portion in the cover member which is positioned in the groove and the groove.

A piezoelectric printing device includes a piezoelectric plate and a substrate with at least one row of drop ejectors. Each drop ejector includes a pressure chamber on a first side of the substrate and a nozzle on a second side of the substrate. The piezoelectric plate is attached to the substrate by a bonding layer. A first electrode layer is disposed on a first surface of the piezoelectric plate proximate to the first side of the substrate. The first electrode layer includes signal lines and ground traces corresponding to each pressure chamber. A second electrode layer including signal input pads and ground return pads is disposed on an outer second side of the piezoelectric plate. Signal lines and ground traces in the first electrode layer are electrically connected to signal input pads and ground return pads respectively on the second electrode layer through conductive vias.

There is provided a liquid discharge head including: first and second common channels extending in a first direction; and a plurality of individual channels each including: a supplying part, a descender part, and a returning part. The returning part includes: a throttle part and a wide part. Each of a plurality of nozzles is located at a position at which each of the plurality of nozzles overlaps with the wide part in a second direction. At a throttle-starting position which is a boundary between the throttle part and the wide part, a length in the second direction of the throttle part and a length in the second direction of the wide part are same.

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 positioned away from the second surface of 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 extending in one direction that is a direction from the top plate toward the second surface, the first side plate includes a first portion that is in contact with the drive IC, and that extends in the one direction, and a second portion positioned in a portion closer to the second surface than the first portion, and the second portion includes a diameter expanding portion having a diameter that expands toward the second surface.

There is provided a head including: a piezoelectric layer; a plurality of individual electrodes located below the piezoelectric layer in an up-down direction; a common electrode located below the piezoelectric layer. The plurality of individual electrodes includes: a first individual electrode array including a plurality of first individual electrodes aligned in a first direction; and a second individual electrode array including a plurality of second individual electrodes aligned in the first direction. The common electrode includes: a plurality of first facing portions which are demarcated to correspond to the plurality of first electrodes, respectively; a plurality of second facing portions which are demarcated to correspond to the plurality of second electrodes, respectively; and a connecting portion located between the plurality of first facing portions and the plurality of second facing portions, and connecting the plurality of first facing portions and the plurality of second facing portions.

A liquid jetting apparatus includes: individual channels; and a manifold commonly provided for the individual channels. Each of the individual channels has: a nozzle; a pressure chamber arranged away from the nozzle in a predetermined direction to extend along a plane orthogonal to the predetermined direction and connected to the manifold, a connecting channel connected to the pressure chamber to form at least a part of a channel communicating the pressure chamber and the nozzle, and a circulation channel connected to the connecting channel to form a part of a channel communicating the connecting channel and the pressure chamber. The connecting channel has a throttle, and the throttle has a smaller diameter along the plane orthogonal to the predetermined direction than a diameter, of a part of the connecting channel except the throttle, along the plane orthogonal to the predetermined 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.

An embodiment of the present invention provides an inkjet head including: a head body having a storage chamber capable of storing ink; a first inlet pipe and a second inlet pipe connected to the head body and which extend in first different directions and inject the ink in the first different directions; a first outlet pipe and a second outlet pipe connected to the head body and which extend in second different directions and eject the ink in the second different directions; and a nozzle plate positioned under the head body and which includes a plurality of nozzles.