Provided is a liquid ejection device capable of ejecting a minute liquid droplet with stability, in which a capacity of a pressure chamber facing a second partition portion increases, and a capacity of the pressure chamber facing a first partition portion decreases, at a time when a voltage is applied so that a potential of a first electrode becomes lower than a potential of a second electrode, compared to a time when a voltage is applied so that the potential of the first electrode becomes the same as the potential of the second electrode, the first electrode and the second electrode being included in an electrode formed on each of both side surfaces of partitions.

An ink jet head includes a base, walls attached to the base and defining flow paths between the walls, the flow paths including first and second flow paths alternating with one another, a nozzle plate comprising openings, each of which communicates with one of the first flow paths, an ink supply unit fluidly coupled to the first flow paths, electrodes on side surfaces of the walls, first and second wirings, each extending along the base and each being individually connected to one of the electrodes, a plurality of first protective layers on the base, the first wiring extending between a first pair of the first protective layers and the second wiring extending between a second pair of the first protective layers, and a second protective layer comprising an electrically insulating layer covering the first protective layers and the first and second wirings.

A flow path forming substrate in which an individual flow path which communicates with a nozzle opening that discharges liquid is formed; and a communication plate in which a recess portion which configures at least a part of a common flow path that is common to and communicates with the plurality of individual flow paths is provided to be open on a side opposite to the flow path forming substrate, are provided, the recess portion includes a first recess portion, and a second recess portion which is deeper than the first recess portion, the communication plate includes a supply path which is provided to be open on a bottom surface of the first recess portion, communicates with the recess portion and the individual flow path, and becomes a throttle portion that throttles a flow path with respect to the individual flow path, and a communication path which communicates with the individual flow path and the nozzle opening, and in the individual flow path, a throttle portion which throttles the individual flow path from a part that communicates with the supply path to a part that communicates with the communication path, is not provided.

The head has a passage member having a nozzle and a pressurizing chamber which is communicated with the nozzle and is positioned on the side opposite to the side where the nozzle is opened, a piezoelectric actuator substrate which is superimposed on the passage member so as to cover the pressurizing chamber, and a flexible printed circuit which faces the piezoelectric actuator substrate from the opposite side to the passage member. The piezoelectric actuator substrate has a piezoelectric body which is exposed on the flexible printed circuit side. The piezoelectric body has a via hole opened toward the flexible printed circuit and has a projection portion at the edge part of the via hole which projects to the flexible printed circuit side.

A print head includes a body, holding a droplet jetting device, a flexible electrical connection element, and an adhesive covering and securing first and second contact pad structures together. The droplet jetting device has an actuator for jetting a droplet of liquid from a nozzle of the droplet jetting device. The actuator is in electrical connection to the first contact pad structure. The flexible electrical connection element has, at one end, the second contact pad structure, which is mounted onto the first contact pad structure. The first and second contact pad structures each have an interface surface which contacts the interface surface of the other to form an electrical connection. At least one of the first contact pad structure and the second contact pad structure includes a recessed portion as compared to a wider portion positioned between the recessed portion and the interface surface.

A printing element is used, which includes a substrate, an intermediate layer, and a channel forming member layered in this order. The substrate has a common liquid chamber. The channel forming member has a second surface that is a surface facing the substrate via the intermediate layer, and a first surface that is an opposite surface to the second surface. The first surface is formed with a plurality of ejection ports that eject liquid from the common liquid chamber. The second surface is formed with a plurality of channels that make each of the plurality of ejection ports and the common liquid chamber communicate with each other, and a plurality of substantially parallel beam structures, the plurality of beam structures forming a slit portion therebetween.

An element substrate of a liquid ejection head includes an ejection element for ejecting a liquid, a plurality of electrode pads for receiving power for causing the ejection element to eject the liquid, and a sensor for detecting that the liquid has invaded the vicinity of the plurality of electrode pads. The sensor has first wiring connected with one electrode pad of the plurality of electrode pads and second wiring connected with one electrode pad different from the electrode pad connected with the first wiring.

A die for a printhead is provided in examples. The die includes a number of fluidic actuator arrays, proximate to a number of fluid feed holes. A number of address lines are disposed proximate to a number of logic circuits on a low-voltage side of the fluid feed holes. An address decoder circuit is coupled to at least a portion of the address lines to select a fluidic actuator in a fluidic actuator array for firing. The address decoder circuit is customized to select a different address for each fluidic actuator in the fluidic actuator array. A logic circuit triggers a driver circuit located in a high-voltage side of the plurality of fluid feed holes opposite the low-voltage side, based, at least in part, on a bit value for the fluidic actuator array, the fluidic actuator selected by the address decoder circuit, and a firing signal.

An electronic device includes a first member configured by single crystal silicon, in which the first member includes a first surface configured by a {110} plane in the single crystal silicon, a second surface of an opposite side from the first surface, a through-hole which spans from the first surface to the second surface, a first recessed portion which is opened in the first surface and includes a wall surface configured by a {111} plane, the wall surface being inclined by an angle greater than 0° and less than 90° with respect to the first surface in the single crystal silicon, and a second recessed portion opened in the second surface, and a level difference surface having a different inclination to that of the {111} plane is provided in the middle of the wall surface of the first recessed portion in a depth direction.

Long-term reliability of a liquid ejection head substrate and a liquid ejection head is improved by suppressing dissolution of an intermediate layer due to anodization. A liquid ejection head substrate including: a flow passage forming member having an ejection orifice and a flow passage; a heating resistance element for ejecting a liquid; an insulating layer covering the heating resistance element; a protecting layer whose surface is exposed to the flow passage; and an intermediate layer provided between the flow passage forming member and the protecting layer, in which the intermediate layer contains a material represented by a following composition formula (I): Si.sub.w1O.sub.x1C.sub.y1 (I), 39≤w1≤62 (at. %), 32≤x1≤55 (at. %), and 6≤y1≤29 (at. %), and w1+x1+y1=100 (at %).