Printhead Nucleation Detection Using Thermal Response

A method of controlling a printer of the type having a printhead with a plurality of nozzles, a heater associated with each nozzle, and where the heater is responsive to a pulse for heating ink and jetting the ink through the nozzle, and a thermal sensor for measuring printhead temperature, comprising:

• preheating the printhead to a predetermined temperature;
• successively driving the heater with a heating interval, where each successive heating interval is characterized by shorter pulse width pulses at a higher pulse frequency;
• processing printhead temperature data received during each heating interval to identify a desired criterion;
• when the desired criterion is found, associating the desired criterion with a heating interval in which ink nucleation begins to cease and a main fire pulse width used in the heating interval in which ink nucleation began to cease;
• and
• driving the heater with the main fire pulse width during subsequent printer operations to print characters on a print medium.

A printer of the type having a printhead with a plurality of nozzles, a heater associated with each nozzle, and where the heater is responsive to a pulse for heating ink and jetting the ink through the nozzle, and a thermal sensor for measuring printhead temperature, comprising:

• a controller programmed to:
• successively drive the heater during a heating interval where each successive heating interval is characterized by shorter pulse width pulses at a higher pulse frequency;
• process printhead temperature data received during each heating interval to identify a desired criterion;
• associate the desired criterion with a heating interval and a main fire pulse width used in the heating interval;
• and
• drive the heater with the main fire pulse width during subsequent printer operations to print characters on a print medium.