Patent attributes
A liquid ejection head includes an ejection port for ejecting liquid, a liquid chamber communicating with the ejection port, and a substrate having a heat generating resistor arranged in the liquid chamber at a position corresponding to the ejection port and a bubble detecting device arranged on the heat generating resistor for controlling driving of the heat generating resistor by detecting a bubble produced by the heat generated by the heat generating resistor. The bubble detecting device has two electrodes arranged in the liquid chamber and, as viewed in the direction perpendicular to the substrate, one of the two electrodes is arranged at a position overlapping the heat generating resistor whereas the other one of the two electrodes is arranged at a position not overlapping the heat generating resistor.