An ink manifold for use with a heater chip in an inkjet printhead, including a first planar surface and a second opposite planar surface, a plurality of ink channels located on the first planar surface of the ink manifold for supplying ink to the heater chip, and a plurality of ink ports located on the second opposite planar surface of the ink manifold, each of the plurality of ink ports being in liquid communication with a respective one of the plurality of ink channels, each of the plurality of ink channels having a bottom wall defined by bottom wall portions that rise from each ink port within the ink channel to a maximum height at an angle of at least 12 degrees.

An inkjet nozzle device includes a resistive heater element for ejecting ink droplets through a nozzle opening. The resistive heater element includes: an aluminide layer having a native passivating oxide and a tantalum oxide layer disposed on the native passivating oxide of the aluminide layer. The tantalum oxide layer is a relatively thin layer, which may be deposited using atomic layer deposition.

An element substrate including a base having a heat-generating resistor element which generates thermal energy used for discharging a liquid; an electrically conductive protective layer covering the heat-generating resistor element; an insulating layer provided between the heat-generating resistor element and the protective layer; and a potential applying unit for applying a potential to the protective layer such that a potential of the protective layer is lower than a potential at one end of the heat-generating resistor element and higher than a potential at the other end of the heat-generating resistor element with a voltage being applied between the one end and the other end of the heat-generating resistor element.

Provided is a recording element substrate, including: an ejection module including a heat generating resistive element; a current detection circuit including a current detection resistor connected in series between the heat generating resistive element and a voltage application terminal for applying voltage from a power supply to the heat generating resistive element, and a voltage detector for detecting a differential voltage at each end of the current detection resistor; an ejection circuit provided between the voltage application terminal and the heat generating resistive element, for applying voltage for causing the heat generating resistive element to generate heat from the voltage application terminal to the heat generating resistive element; and a control circuit for selecting any one of the current detection circuit and the ejection circuit.

Provided is a technique that enables voltages to be applied, with high precision, to an electrode layer for inhibition and removal of koge while suppressing increase in the size a substrate. A liquid ejection head substrate includes: electrothermal conversion elements that apply heat to a liquid; an upper electrode part in which a plurality of upper electrodes that protect the electrothermal conversion elements are formed at positions where the upper electrodes come into contact with the liquid; a counter electrode part which is provided to correspond to the upper electrode part and in which a plurality of counter electrodes are formed to be electrically connectable to the upper electrodes via the liquid; and a generation unit that generates a voltage to be applied to at least one of the upper electrode part and the counter electrode part.

A liquid discharge head includes: an actuator substrate; an electromechanical transducer held by the actuator substrate; a damper; and a damper holding substrate holding the damper, wherein the damper disposed between the actuator substrate and the damper holding substrate and joined to the actuator substrate and the damper holding substrate with an adhesive, the damper has a joint portion having a recess or a through hole.

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.

An object of the present disclosure is to provide a recycling method of a cartridge that has the potential to contribute to the achievement of a sustainable society, such as a decarbonized society/circular society. The recycling method of the cartridge includes: performing electrical evaluation to evaluate an electrical characteristic of a printing element substrate by supplying electric power to the printing element substrate from a wiring substrate; performing outer appearance evaluation to evaluate an outer appearance of the cartridge based on the number of ejection ports having a problem out of multiple ejection ports; and determining whether to recycle the cartridge based on a result of the electrical evaluation and a result of the outer appearance evaluation.

A liquid ejection head substrate is installed in a liquid ejection head that has a plurality of ejection nozzles for ejecting liquid. The liquid ejection head substrate includes: a plurality of element arrays configured with a plurality of functional elements which correspond to the ejection nozzles and are arranged into the plurality of element arrays placed side by side in an arrangement direction (the X direction) which intersects with an array direction (the Y direction) of the functional elements; and a dummy functional element array configured with a plurality of dummy functional elements which are not electrically driven and are arranged into the dummy functional element array along the array direction (the Y direction). The dummy functional element array is arranged at a side of the plurality of element arrays with respect to the arrangement direction (the X direction).

Provided is a liquid ejection apparatus capable of executing a kogation removal process at appropriate timing, thereby stably ejecting a liquid without shortening the lifespan of a head. For this purpose, the timing to execute the kogation removal operation of dissolving a metal in a protective layer through an electrochemical reaction with the liquid is determined based on information on an ejection characteristic of the liquid.