A fluid ejection device including a printhead die having a plurality of layers, including a single metal layer, and having an integrated ink level sensor. The ink level sensor includes an ink chamber above the metal layer, a metal plate of a sense capacitor disposed in the metal layer, and a clearing resistor circuit disposed in the metal layer including four clearing resistors arranged in a surround-4 configuration about the metal plate and electrically connected in parallel between a voltage potential and ground, wherein adjacent ends of at least two clearing resistors are not directly connected to one another so as to leave a gap between the adjacent ends in the metal layer. A metal lead in the metal layer extends through the gap to the metal plate.

An electronic device includes: a first substrate having a first surface and a second surface opposite from the first surface; a second substrate facing the first surface; driven elements provided at the second substrate; a drive circuit facing the second surface; a first interconnect provided at the first surface; a second interconnect provided at the second surface; a through-substrate interconnection part penetrating the first substrate in a thickness direction thereof; a first bump part; and a second bump part. The drive circuit is capable of outputting drive signals for driving the driven elements. The through-substrate interconnection part electrically connects the first interconnect and the second interconnect. The first bump part electrically connects the first interconnect and the driven elements. The second bump part electrically connects the second interconnect and the drive circuit. The through-substrate interconnection part has an electrical resistance lower than an electrical resistance of the second bump part.

A piezoelectric device includes an actuator substrate that includes a plurality of piezoelectric element rows having a plurality of piezoelectric elements, and a wiring substrate that is disposed so as to face the actuator substrate. The piezoelectric element rows include a common electrodes common to the plurality of the piezoelectric elements. The actuator substrate includes a plurality of first common wirings connected to each of the common electrodes of the plurality of the piezoelectric element rows. The wiring substrate includes a plurality of second common wirings connected to each of the first common wirings of the plurality of piezoelectric element rows, and a plurality of auxiliary wirings buried in a groove portion formed in the wiring substrate. The auxiliary wirings are connected to each of the second common wirings, and the plurality of auxiliary wirings are not connected to each other.

In an example, a printhead includes a memristor, in which the memristor may include a first electrode, a second electrode positioned in a crossed relationship with the first electrode to form a junction, and a switching element positioned at the junction between the first electrode and the second electrode, in which the switching layer includes a via formed in the switching element to reduce an area of the switching element.

A MEMS device includes a plurality of movable regions, wiring lines extending along a first direction from the movable regions, and electrodes connected to the wiring lines. The electrodes include connection regions for connecting other electrode terminals to the connection regions. A plurality of the connection regions are disposed along a second direction intersecting the first direction. A distance between centers of connection regions that are adjacent in the second direction is longer than a distance between centers of movable regions that are adjacent in the second direction.

A wiring substrate is provided with a surface wiring on at least one surface, a through hole which passes through the wiring substrate, and a through wiring which is formed in the through hole and is connected to a surface wiring, in which an inner surface of the through hole is a rough surface, and electric resistance of the through wiring is equal to or less than the electric resistance of the surface wiring.

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 piezoelectric device includes an actuator substrate that includes two rows of piezoelectric element rows piezoelectric elements, and a wiring substrate that is disposed so as to face the actuator substrate. The piezoelectric element rows include individual electrodes disposed for each of the piezoelectric elements, and a common electrode common to the piezoelectric elements. The wiring substrate includes a core portion disposed on a surface on the actuator substrate side, an individual wiring portion disposed for each of the piezoelectric element rows that partially covers the core portion, and a common wiring portion disposed for each of the piezoelectric element rows that partially covers the core portion. The two rows of piezoelectric element rows are respectively disposed so as to interpose the core portion. The individual wiring portion and the common wiring portion are respectively electrically connected to the individual electrode and the common electrode.

Ink is circulated through a circulation flow path between a print head and an ink tank. Detection operation for detecting an ink ejection state in an ejection opening in the print head is performed. The ink circulation and the detection operation are simultaneously performed by performing the detection operation in response to a start of the ink circulation.

A print element substrate, comprising a plurality of heating elements, a plurality of detection elements, each configured to detect a temperature of a corresponding heating element, a first current generation unit, a second current generation unit, and a signal output unit, wherein one of the first and second current generation units supplies a current to a first detection element, the other supplies a current to a second detection element, and the signal output unit outputs a signal according to a potential difference between one terminal of the first detection element on a side where a potential variation occurs upon supply of the current and one terminal of the second detection element on a side where a potential variation occurs upon supply of the current.