Method and apparatus for summing temperature changes to detect ink flow
First Claim
1. An apparatus for detecting ink flow through a thermal inkjet printhead, comprising:
- a temperature sensor for sensing a temperature of the printhead as the printhead prints; and
detector circuitry in communication with the temperature sensor for;
summing the temperature of the printhead sensed a number of times during printing of a set of dots to provide a sum;
comparing the sum to a value; and
based on such comparison determining inkflow through the printhead.
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Accused Products
Abstract
A method and apparatus for detecting ink flow through the printhead of an inkjet pen includes sensing the temperature of the printhead substrate as the inkjet pen prints a test pattern into the printer spittoon. The method includes printing a test pattern and storing data representing the temperature of the printhead. The method includes summing the change in temperature of the printhead between an initial point and points at intervals during the printing of a test pattern to provide a thermal history of the printhead. Ink flow is determined from the rate of temperature change during the printing of a test pattern, and from the change in thermal history of the printhead among test patterns.
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Citations
20 Claims
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1. An apparatus for detecting ink flow through a thermal inkjet printhead, comprising:
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a temperature sensor for sensing a temperature of the printhead as the printhead prints; and detector circuitry in communication with the temperature sensor for; summing the temperature of the printhead sensed a number of times during printing of a set of dots to provide a sum; comparing the sum to a value; and based on such comparison determining inkflow through the printhead. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. An apparatus for detecting ink flow through a thermal inkjet printhead, comprising:
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a thermal sense resistor for sensing temperature of the printhead as the printhead prints and producing a resistance proportional to the temperature; and a data processor operably connected to the thermal sense resistor for; calculating sums of temperatures of the printhead from temperature values sensed by the resistor; and determining from a change in the sums whether the ink flow through the printhead is sufficient for printing. - View Dependent Claims (11, 12, 13, 14)
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15. A method of detecting ink flow through a thermal inkjet printhead, comprising the steps of:
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sensing a temperature of the printhead as the printhead prints; summing the temperature of the printhead during the printing of a set of dots to determine a sum; comparing the sum with a value to determine whether the ink flow through the printhead is sufficient for printing. - View Dependent Claims (16, 17, 18, 19, 20)
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Specification