Systems and methods for controlling and testing jetting stability in inkjet print heads
First Claim
1. A system for monitoring characteristics of a voltage signal provided to a PZT capacitor of a print head comprising:
- a digital driver circuit adapted to generate and transmit a signal indicating a nominal slew rate;
a probe circuit coupled to the capacitor for measuring a firing pulse voltage signal provided to the capacitor;
a comparator coupled to the digital driver and the probe circuit adapted to compare a measured slew rate as determined from the measured firing pulse voltage signal with the nominal slew rate and to generate a difference signal indicating a difference in magnitude between the measured slew rate and the nominal slew rate;
an analog driver circuit coupled to the comparator adapted to adjust the slew rate of the voltage signal provided to the capacitor in response to the difference signal received from the comparator; and
an analog/digital converter coupled to the probe circuit adapted to sample the firing pulse voltage signal output from the probe circuit and to provide a digital output signal for diagnostic purposes.
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Accused Products
Abstract
The present invention provides systems, methods, and apparatus for monitoring and controlling a slew rate of a voltage signal provided to a PZT capacitor of a print head. The system includes a digital driver circuit adapted to generate a signal indicating a nominal slew rate, a probe circuit for measuring a firing pulse voltage signal provided to the capacitor, a comparator coupled to the digital driver and the probe circuit comparing a measured slew rate with the nominal slew rate generating a signal indicating a difference between the measured slew rate and the nominal slew rate, an analog driver circuit coupled to the comparator adapted to adjust the slew rate of the voltage signal in response to the difference signal, and an analog/digital converter adapted to sample the voltage signal output from the probe circuit and to provide an output for diagnostic purposes. Numerous other features and aspects are disclosed.
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Citations
21 Claims
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1. A system for monitoring characteristics of a voltage signal provided to a PZT capacitor of a print head comprising:
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a digital driver circuit adapted to generate and transmit a signal indicating a nominal slew rate; a probe circuit coupled to the capacitor for measuring a firing pulse voltage signal provided to the capacitor; a comparator coupled to the digital driver and the probe circuit adapted to compare a measured slew rate as determined from the measured firing pulse voltage signal with the nominal slew rate and to generate a difference signal indicating a difference in magnitude between the measured slew rate and the nominal slew rate; an analog driver circuit coupled to the comparator adapted to adjust the slew rate of the voltage signal provided to the capacitor in response to the difference signal received from the comparator; and an analog/digital converter coupled to the probe circuit adapted to sample the firing pulse voltage signal output from the probe circuit and to provide a digital output signal for diagnostic purposes. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A system for monitoring and controlling a slew rate of a voltage signal provided to a PZT capacitor of a print head comprising:
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a digital driver circuit adapted to generate and transmit a signal indicating a nominal slew rate; a probe circuit coupled to the capacitor for measuring an actual slew rate of the voltage signal provided to the capacitor; a comparator coupled to the digital driver and the probe circuit adapted to compare the measured slew rate with the nominal slew rate and to generate a difference signal indicating a difference in magnitude between the measured slew rate and the nominal slew rate; and an analog driver circuit coupled to the comparator adapted to adjust the slew rate of the voltage signal provided to the capacitor in response to the difference signal received from the comparator. - View Dependent Claims (8, 9, 10, 11, 12, 13)
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14. A method for monitoring characteristics of a voltage signal provided to a PZT capacitor of a print head comprising:
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generating and transmitting a signal indicating a nominal slew rate; measuring a firing pulse voltage signal provided to the PZT capacitor; comparing a measured slew rate as determined from the measured firing pulse voltage signal with the nominal slew rate; generating a difference signal indicating a difference in magnitude between the measured slew rate and the nominal slew rate; adjusting the slew rate of the voltage signal provided to the PZT capacitor in response to the difference signal; sampling the firing pulse voltage signal; and providing a digital output signal for diagnostic purposes based on the sampling. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21)
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Specification