LIQUID EJECTION APPARATUS AND FAILURE DIAGNOSTIC METHOD FOR HEAD UNIT

A liquid ejection apparatus includes a first print head receiving a drive signal and ejecting a liquid, a temperature information output circuit acquiring a first temperature signal indicating a temperature of the first print head and outputting a temperature information signal, and a state determination circuit determining a state of the print head based on the temperature information signal, wherein the first print head includes a first temperature detection unit outputting the first temperature signal, and the state determination circuit determines that the liquid stored in a first pressure chamber is short when the temperature of the first pressure chamber corresponding to the first temperature signal exceeds a first predetermined value, and determines that the liquid stored in the first pressure chamber is not short when the temperature of the first pressure chamber corresponding to the first temperature signal does not exceed the first predetermined value.