A liquid ejection head includes: a first head unit; a second head unit disposed adjacent to the first head unit in a first direction and located on a first side of the first head unit in a second direction; and a heat uniforming unit shared by the first head unit and the second head unit. Each of the first head unit and the second head unit includes: a unit body including an actuator; and a first driver integrated circuit disposed on the first side of the unit body in the second direction. The heat uniforming unit includes a first heat uniforming member disposed on the first side of the first head unit and the second head unit in the second direction. The first heat uniforming member includes a first protrusion located next to the second head unit in the first direction and protruding toward the first head unit.

According to one embodiment, a size of an element substrate is reduced, and a printhead using the element substrate can print high-quality image. The multilayer structured element substrate comprises a plurality of print elements, and a circuit configured to input a data signal and a clock signal used for driving the plurality of print elements. And, a print element array formed by arranging the plurality of print elements in line is diagonally arranged with respect to a side constituting an outer shape of the element substrate. A print element at one end of the print element array is a dummy element not contributing to printing. The circuit is provided not only at the same position as that of the dummy element but also in a layer different from that of the dummy element.

A printed circuit board has a first coefficient of thermal expansion. A compound is molded about the printed circuit board. The compound has a second coefficient of thermal expansion different than the first coefficient of thermal expansion. An interface is between an edge of the printed circuit board and the compound. The interface has a third coefficient of thermal expansion between the first coefficient of thermal expansion and the second coefficient of thermal expansion.

A device detects at least one position of at least a part of a printing material while the printing material is transported in a printing machine. The device includes an optical sensor for establishing a distance between a printing machine component and the printing material. The distance established by the optical sensor is temperature-compensated by a computer.

A liquid ejection head includes: a liquid ejection unit including an ejection element substrate including multiple ejection elements, a first wiring substrate and a second wiring substrate connected with the ejection element substrate and arranged to face each other so as to sandwich the ejection element substrate from a facing direction, a first driving element provided on the first wiring substrate to drive the ejection elements, a second driving element provided on the second wiring substrate to drive the ejection elements, a first cooling member cooling down the first driving element, and a second cooling member cooling down the second driving element. Additionally, in the facing direction, the first cooling member, the first driving element, the second driving element, and the second cooling member are arranged in this order.

An element substrate includes a first heating element configured to generate thermal energy for discharging a liquid by supply of power, a first temperature detecting element configured to detect a temperature of the first heating element, a second temperature detecting element configured to detect the temperature of the first heating element, a first output circuit configured to energize the first temperature detecting element and output a voltage of one terminal of the first temperature detecting element as temperature information; and a second output circuit configured to energize the second temperature detecting element and output a voltage of one terminal of the second temperature detecting element as temperature information. The other terminal of the first temperature detecting element and the other terminal of the second temperature detecting element are connected to a common wire maintained at a predetermined potential.

A liquid ejecting head includes: a substrate including ejection openings configured to eject liquid; a flow-path member supporting the substrate and having a supply flow path that supplies the substrate with liquid, on one side in a first direction intersecting the arrangement direction of the ejection openings and a collection flow path that collects liquid from the substrate, on the other side; and a heating unit that heats an ejection region including the liquid ejection openings in the substrate. On both sides of the ejection region of the substrate in the first direction, the collection flow path is located on a side where the distance between the ejection region and a side of the substrate in the first direction is longer and the supply flow path is located on a side where the distance between the ejection region and a side of the substrate in the first direction is shorter.

A print element substrate, comprising a base, a heater provided on the base and configured to generate heat used to discharge ink, a flow path member, which forms an ink flow path, configured to form, together with the base, a bubbling chamber in which the ink is bubbled by the heat of the heater provided in a bottom surface of the bubbling chamber, and a temperature sensor capable of detecting a temperature of the bubbling chamber, the temperature sensor being formed of the same material as the heater and provided in the same layer as the heater on the base.

A fluid ejection die may include a fluid actuator, a substrate supporting the fluid actuator, a chamber layer supported by the substrate and a bypass passage in the substrate. The substrate may include a closed inlet channel having an inlet opening for connection to an outlet of a fluid source and an outlet channel having an outlet opening of a first size for connection to an inlet of the fluid source. The chamber layer includes a recirculation passage to supply fluid for ejection by the fluid actuator through an ejection orifice and to circulate fluid across the fluid actuator from the closed inlet channel to the outlet channel. The bypass passage is of a second size less than the first size and connects the inlet channel to the inlet of the fluid source while bypassing any fluid actuator provided for ejecting fluid through an ejection orifice.

A liquid discharge head includes a heat dissipation plate, a head body, a supply pipe, and a shielding portion. The heat dissipation plate is in contact with a heat generation source. The head body includes a discharge hole configured to discharge a liquid. The supply pipe supplies a liquid to the head body. The shielding portion is provided between the heat dissipation plate and the supply pipe and is separated from the heat dissipation plate and the supply pipe.