Patent ID: 7950765

Claim:
A liquid discharge head comprising: an electrothermal transducing member for generating heat energy for discharging liquid from a discharge port upon application of electrical energy; and a temperature detecting circuit comprising a temperature detecting element for substantially measuring a temperature of said electrothermal transducing member, which increases in accordance with application of the electrical energy, said temperature detecting circuit comparing a maximum temperature of said electrothermal transducing member measured by said temperature detecting element with a reference temperature, wherein said temperature detecting element comprises a material having a resistance value varying in accordance with the temperature, said temperature detecting circuit comprises a constant current circuit for supplying a constant current to said temperature detecting element, a voltage detection circuit for detecting a voltage applied to said temperature detecting element, and a first switching element for controlling a supply of the current flowing in said temperature detecting element, and said electrothermal transducing member comprises a second switching element for controlling a supply of the electrical energy, said first switching element and said second switching element being controlled with a common signal.