Patent ID: 8109591

Claim:
A method of controlling delivery of electrical power to a printhead in a printer comprising: generating a first electrical signal corresponding to a temperature in a printhead; monitoring the first electrical signal with a first electronic circuit that is configured to terminate delivery of electrical power to a printhead in response to detection of a safety event; generating an over-temperature signal with the first electronic circuit in response to the temperature corresponding to the first electrical signal exceeding a temperature threshold; monitoring the first electrical signal with a second electronic circuit that is configured to regulate an amount of electrical power delivered to the printhead; generating a circuit fault signal with a third electronic circuit in response to the first electrical signal exceeding a reference signal; monitoring the first electrical signal with a fourth and a fifth electronic circuit; generating an over-temperature signal with the fourth electronic circuit in response to the temperature corresponding to the first electrical signal exceeding a temperature threshold, the first and the fourth electronic circuits being implemented with different integrated circuits; generating a circuit fault signal with the fifth circuit in response to the temperature corresponding to the first electrical signal being greater than a second reference signal, the second and the fifth electronic circuits being implemented with different integrated circuits; and decoupling electrical power from the printhead in response to the generation of the over-temperature signal or the circuit fault signal.