Patent ID: 8191988

Claim:
A liquid ejection head comprising: a liquid-ejection head substrate including an element, which generates thermal energy used for ejecting a liquid from an ejection port, and a protective layer, which covers at least the element, and in which two or more first layers and two or more second layers are alternately stacked; a flow passage member which has a wall of a flow passage communicating with the ejection port and which defines the flow passage by contacting the liquid-ejection head substrate so that the wall is disposed toward the inside; and a flow-passage electrode disposed in the flow passage, wherein in a case where a voltage is applied so that the protective layer functions as an anode electrode and the flow-passage electrode functions as a cathode electrode, a material of the first layers dissolves when in contact with the liquid and a material of the second layers is passivated when in contact with the liquid.