Ink level sensing for disposable ink jet print head cartridges
AssigneeLexmark International, Inc.
InventorMark Joseph Edwards
Life of this patent
Estimating the term…
Abstract
A printer having a disposable print head which contains a consumable ink supply includes the capability of determining the level of ink in the print head without directly measuring the ink supply. The print head includes a number of resistors which can be driven to an open circuit condition by the printer. The printer includes a counter and memory for tracking the usage of the print head and a driver for selectively driving the print head resistors to an open circuit condition based upon such usage. The printer is also capable of detecting the condition of the resistors on the print head and producing a resultant visual display.
Claims8
A printer, including a disposable print head having a plurality of resistance paths, several discrete actuators, and an ink supply, comprising:
- means for providing energization of each of the several discrete actuators of the print head to dispense ink from the ink supply onto a record medium;
- means for maintaining a cumulative record of energizations of the print head, including a counter which stores a count of said energizations of the print head, and further including a non-volatile memory;
- means for periodically adding the count from the counter into a cumulative count in the non-volatile memory;
- and
- means, responsive to the cumulative record, for changing the resistance in the resistance paths on the print head.
A method of recording an ink level on a disposable print head having a plurality of resistance paths, several discrete actuators, and an ink supply, comprising the steps of:
- providing energization of each of the several discrete actuators of the print head to dispense ink from the ink supply onto a record medium;
- maintaining a count of actuations of the print head in a counter;
- periodically adding the count from the counter into a cumulative count in a non-volatile memory;
- and,
- changing the resistance in the resistance paths on the print head in response to the cumulative count.
A printer, comprising:
- a disposable print head having an ink supply, and a plurality of resistance paths segregated from a plurality of actuator circuits, wherein each of said plurality of actuator circuits includes an actuator;
- means for providing actuation of each actuator of the print head to dispense ink from the ink supply onto a record medium;
- means for maintaining a cumulative record of actuations of the print head, including a counter which stores a count of said actuations of the print head, and further including a non-volatile memory;
- means for periodically adding the count from the counter into the cumulative record in the non-volatile memory;
- and
- means, responsive to the cumulative record, for changing the resistance in the resistance paths on the print head.
Dependencies are inferred from the claim text.