On a liquid ejection head substrate, an upper protective layer, as well as coming into contact with a resin layer of a path forming member having an ejection opening, comes into contact with ink in a heat generating portion inside the channel formed. The laser is operative at near infrared wavelength region, including the eye-safe region. The image display device also includes a temperature sensor to detect the variation of the ambient temperature of the display device and provide temperature data corresponding to the variation of the ambient temperature. A tool is used to evert the graft end region.