Appeal 2007-0960
Application 10/066,529
use profiles to provide information useful in controlling printhead
temperature (Smith, col. 1, l. 64 - col. 2, l. 2).
In short, the thermistor’s output in Smith (i.e., the signal used to
“closely estimate” the printhead temperature) depends on, among other
things, the ejection history of the ejection elements and whether the ejection
elements have been fired. This detected temperature is inputted to
microprocessor 2 which accounts for these and other factors to control the
printhead temperature. This controlled temperature, in turn, is detected by
the thermistor and sent to the microprocessor.
Even if we assume, without deciding, that Smith’s controller is
configured to estimate the actual printhead temperature solely on the basis
measured temperature of the printhead, that measured temperature, however,
is based at least in part on the other two recited factors--namely, the thermal
response model and the ejection history. That is, both the thermal response
model and the ejection history in Smith are substantial factors in
determining the temperature sensor’s output signal. As key aspects of
Smith’s temperature control system, the thermal response model and the
ejection history directly contribute to controlling the printhead’s
temperature--and therefore the temperature detected by the sensor. The
sensor’s output signal, in turn, is used to estimate the temperature to
ultimately control the temperature.
Simply put, estimating the actual temperature of the printhead
assembly in Smith’s temperature feedback control system necessarily is
based at least in part on all three recited factors: (1) the measured or current
operating temperature of the printhead assembly; (2) a thermal response
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