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 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 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 liquid discharge head including a channel unit that includes plates stacked on top of each other in a first direction and is formed having individual channels, a first common channel, and a second common channel. The first and second common channels communicate with the individual channels. Each individual channel includes a nozzle, a pressure chamber, a descender, a first throttle channel, and a second throttle channel. The plates include a nozzle plate, a pressure chamber plate, and a first plate formed having a first through hole that constitutes part of the descender. A center portion of the nozzle is positioned at a side opposite to the second throttle channel in the second direction with respect to a center portion of the descender. The descender has a protruding channel portion that is formed in the first plate, is positioned at an end at the side opposite to the second throttle channel in the second direction, and protrudes toward the side opposite to the second throttle channel beyond any other portion of the descender.

A liquid discharge head includes: a first flow path member that discharges a liquid; a second flow path member including a supply flow path for sending the liquid to the first flow path member, and a collecting flow path for collecting the liquid from the first flow path member. The supply flow path includes a supply branch flow path that branches out at a center portion of the second flow path member in the first direction and extends in a first direction and in a third direction opposite thereto. The collecting flow path includes a collecting branch flow path that branches out at the center portion of the second flow path member in the first direction and extends in the first direction and in the third direction. When viewed in plan, the supply branch flow path and the collecting branch flow path overlap each other.

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 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.

Provided is an inkjet head including a plurality of ink dischargers, a first common ejection flow path, and a second common ejection flow path. Each of the ink dischargers includes an ink storage, a pressure changer, a nozzle, and a first individual ejection flow path and a second individual ejection flow path that communicate to the ink storage and through which ink is ejected from fee ink storage but not supplied to the nozzle. The first common ejection flow path communicates to a plurality of first individual ejection flow paths of the respective plurality of the ink dischargers, and the second common ejection flow path communicates to a plurality of second individual ejection flow paths of the respective plurality of fee ink dischargers. A shape of a first section of first common ejection flow path into which ink flows from the plurality of first individual ejection flow paths is different from a shape of a second section of the second common ejection flow path into which ink flows from the plurality of second individual election flow paths.

A liquid ejection head having a channel member which includes an ejection hole surface and a pressurization chamber surface opposite thereto. An actuator substrate overlaps the pressurization chamber surface. The channel member includes a plurality of ejection holes opening in the ejection hole surface, a plurality of pressurization chambers individually communicating with the plurality of ejection holes and arranged in plan view of the pressurization chamber surface, and a plurality of dummy pressurization chambers positioned outside of the predetermined region in plan view of the pressurization chamber surface. The actuator substrate includes a plurality of pressurization portions that individually pressurize the pressurization chambers, and a plurality of dummy pressurization portions that individually pressurize the dummy pressurization chambers. The dummy pressurization chambers communicate with each other via a plurality of communication paths. A closed space including the plurality of dummy pressurization chambers and the plurality of communication paths is hermetically closed.

A liquid discharge head includes a flow channel member that includes discharge holes, pressurizing chambers that are linked to the discharge holes, respectively, a first common flow channel(s) that is/are commonly linked to the pressurizing chambers, a second common flow channel(s) that is/are commonly linked to the pressurizing chambers, a first flow channel that links the pressurizing chambers and the first common flow channel(s), and a second flow channel that links the pressurizing chambers and the second common flow channel(s), and pressurizing parts that pressurize the pressurizing chambers, respectively, wherein the first flow channel includes a first connection flow channel that connects the first common flow channel(s) and first separate flow channels that are linked to one of the pressurizing chambers, and one of the first common flow channel(s) includes sets that are composed of the first connection flow channel and the first separate flow channels.