A print head die includes a storage element. The print head die includes a plurality of analog devices. The storage element is to store an authentication value. The authentication value is generated based on comparisons of the measured electrical characteristics of at least some of the analog devices.

Provided is a technique which can inspect liquid ejection energy without changing electric wiring on an ejection element substrate of a liquid ejection head or ejecting liquid from the liquid ejection head. A liquid ejection head as an ejection-energy inspection target includes an ejection element substrate having a substrate, a heat generation portion having an electrothermal converter on the substrate, a protective film covering the electrothermal converter, and an organic layer covering the electrothermal converter and the protective film. For this liquid ejection head, an electrical resistance value of the electrothermal converter is acquired as a first measurement result, and the film thickness of a film thickness measurement portion of the ejection element substrate where the protective film is exposed is acquired as a second measurement result. Further, information on ejection energy needed to eject liquid from the ejection port is obtained based on the first and second measurement results.

A technique by which deterioration of a heat resistor can be detected more accurately is provided. There are included a printing head configured to eject an ink from a nozzle provided so that the nozzle corresponds to a heat resistor and perform printing by applying a pulse voltage to the heat resistor; an obtaining unit configured to obtain a prediction resistance value of the heat resistor according to a unique value of the heat resistor and a setting value to drive the heat resistor; a measurement unit configured to measure the resistance value of the heat resistor; and a determination unit configured to determine based on the prediction resistance value and the resistance value whether deterioration arises in the heat resistor.