A method of detecting an organic residue is provided. The method comprises a step of bringing a liquid A into contact with a surface of a base material; a step of measuring the contact angle (i) of a liquid B on the surface with which the liquid A came into contact; a step of heating and drying the base material; a step of measuring the contact angle (ii) of the liquid B on the dried surface; and a step of comparing the contact angle (i) with the contact angle (ii).

To provide dummy openings having at least one of arrangement and shape determined depending on the shape of a non-effective region.

A process for forming inkjet nozzle devices on a frontside surface of a wafer substrate. The process includes the steps of: (i) providing the wafer substrate having a plurality of etched holes defined in the frontside surface, each etched hole being filled with first and second polymers such that the second polymer is coplanar with the frontside surface; (ii) forming the inkjet nozzle devices on the frontside surface using MEMS fabrication steps; and (iii) removing the first and second polymers via oxidative ashing, wherein first and second polymers are different.

A method of manufacturing a structure that includes a substrate provided with a through hole, and a resin layer provided on a front surface of the substrate to close the through hole, includes, in order, preparing the substrate including the through hole and including a support substrate on a back surface of the substrate to close the through hole, bonding a dry film to a front surface of the substrate, the dry film including a support member and a resin layer on the support member, to close the through hole with the resin layer and turn the through hole into a closed space with the substrate, the support substrate, and the dry film, opening the through hole turned into the closed space from the support substrate side, and separating the support member from the dry film while retaining the resin layer on the front surface of the substrate.

A printhead may include a nozzle, a firing chamber fluidly coupled to the nozzle, a printing fluid slot fluidly coupled to the firing chamber, and a sensor to detect a plurality of complex impedance values of a printing fluid at the printhead over a plurality of frequencies and create a printing fluid signature of the printing fluid. A method of determining at least one characteristic of a printing fluid provided to a printhead ma include, with a number of sensors, applying an alternating current at a plurality of frequencies over time to the printing fluid to receive a plurality of complex impedance values and comparing the plurality of complex impedance signals to a number of stored signals.

A method for manufacturing a liquid ejection head includes forming a water-repellent layer containing a condensate of a first hydrolyzable silane compound and a second hydrolyzable silane compound, and irradiating the water-repellent layer with light including a light ray having a wavelength of less than 270 nm, wherein the first hydrolyzable silane compound contains a fluorine-containing group but no carbonyl group between the fluorine-containing group and a silicon atom, and the second hydrolyzable silane compound contains a fluorine-containing group and a carbonyl group between the fluorine-containing group and a silicon atom.

A liquid ejection head includes an ejection opening member having an ejection opening therein through which a liquid is ejected, and a liquid-repellent layer over the ejection opening member. The liquid-repellent layer contains a fluorine-containing compound, metal oxide particles, and an amphiphilic compound.

A liquid ejection head 4 includes a substrate 1 provided with an energy-generating element 5, an ejection orifice forming member 2 that is formed on the substrate 1 and includes an ejection orifice 3 from which liquid is ejected, a reinforcing rib 10 provided in the ejection orifice forming member 2, and a recess 6 that is formed in the substrate 1 and forms a part of a flow path of liquid, wherein the reinforcing rib 10 is disposed in the inside of the recess 6.

There is provided a method for manufacturing a liquid discharge head including a liquid discharge head substrate and a flow path forming member, the liquid discharge head substrate having a base, a pressure generation portion provided at a front surface of the base to generate pressure for discharging a liquid, and a supply port for supplying the liquid to the pressure generation portion, and the flow path forming member forming a flow path for feeding the liquid supplied from the supply port to the pressure generation portion. The method includes removing a sacrificial layer by etching the base from a back surface of the base, in a state in which an end covering portion of a cover layer for covering the sacrificial layer is covered with the resin layer. The method suppresses formation of a crack in the end covering portion that covers the end portion of the sacrificial layer.

A liquid ejection head including a substrate, an energy generating element provided on the substrate, a film provided on the substrate and the energy generating element, and a flow path forming member provided on the substrate, forming a flow path of a liquid between the flow path forming member and the substrate, and having an ejection orifice at a position faced with the energy generating element, characterized in that the substrate has a supply path of the liquid communicating with the flow path, the flow path forming member has a structure protruding toward the supply path, and a peripheral shape of a distal end portion of the structure is a curved surface shape.