Patent ID: 7722148

Claim:
A liquid discharge head comprising a plurality of electrothermal transducing members provided on a substrate to generate heat energy for discharging liquid from discharge ports, comprising: a plurality of temperature detecting elements, each temperature detecting element having two terminals, wherein each temperature detecting element is formed immediately under one of the plurality of electrothermal transducing members to sandwich an insulating film; and a temperature detecting circuit for detecting temperature information from each of the temperature detecting elements, wherein the temperature detecting circuit comprises a constant current circuit connected to one terminal of each of the plurality of temperature detecting elements via a plurality of first switching elements and commonly connected to at least the other terminal of each of the plurality of temperature detecting elements, wherein the temperature detecting circuit further comprises a voltage detection circuit for detecting a voltage between both terminals of one of the plurality of temperature detecting elements supplied with constant current from the constant current circuit when a corresponding one of the first switching elements is in an on state, wherein the temperature detecting circuit further comprises a controlling circuit controlling an on or off state of each of the plurality of first switching elements, and wherein the temperature detecting circuit further comprises second switching elements provided for each of the plurality of electrothermal transducing members, for controlling voltage supply to the plurality of electrothermal transducing members, and the controlling circuit further controls an on or off state of the second switching elements for the plurality of electrothermal transducing members.