Apparatus and method for detecting ink in a reservoir
AssigneeXerox Corporation
InventorsMirza Sabanovic, David L. Knierim, Michael Kenneth Oehl
Life of this patent
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Abstract
A method detects the level of ink in a printhead reservoir by monitoring the power drawn by a thermistor positioned within the printhead reservoir. The method includes dissipating power in a thermistor in an ink reservoir, controlling the power dissipated in the thermistor to maintain the thermistor at a temperature that is a fixed differential above a reservoir temperature, measuring a parameter that corresponds to the power dissipated in the thermistor, and comparing the measured parameter to a predetermined value to detect ink in the reservoir contacting the thermistor.
Claims20
A method for detecting ink in an ink reservoir comprising:
- dissipating power in a thermistor in an ink reservoir;
- controlling the power dissipated in the thermistor to maintain the thermistor at a temperature that is a fixed differential above a reservoir temperature;
- measuring a parameter that corresponds to the power dissipated in the thermistor;
- and
- comparing the measured parameter to at least one predetermined value to detect ink in the reservoir contacting the thermistor.
An ink level detection system for use in a printer comprising:
- a thermistor positioned within an ink reservoir of a printer;
- a switch configured to couple a voltage to the thermistor in response to a control signal being received at the switch;
- a comparator having one input coupled to a voltage across the thermistor and another input coupled to a threshold voltage, the comparator generating the control signal received by the switch;
- and
- a digital controller coupled to the comparator and configured to measure a parameter corresponding to a dissipation of electrical power in the thermistor during a predetermined time period and to compare the measured parameter to at least one predetermined value to detect ink in the reservoir contacting the thermistor.
Dependencies are inferred from the claim text.