Method for controlling the over-energy applied to an inkjet print cartridge using dynamic pulse width adjustment based on printhead temperature

• US 6,302,507 B1
• Filed: 10/13/1999
• Issued: 10/16/2001
• Est. Priority Date: 10/13/1999
• Status: Expired due to Term

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Hewlett-Packard Company (HP Inc.)
• Inventors: Prakash, Satya, Holstun, Clayton L, Lassar, Noah C., Askeland, Ronald A
• Primary Examiner(s): VO, ANH T N
• Application Number:
  US09/416,800
• Time in Patent Office: 734 Days
• Field of Search: 347/5, 347/9, 347/10, 347/11, 347/14, 347/19, 347/57, 372/34
• US Class Current: 347/14
• CPC Class Codes: B41J 2/04506 aiming at correcting manufacturing tolerances
• CPC Class Codes: B41J 2/04515 preventing overheating
• CPC Class Codes: B41J 2/04543 Block driving
• CPC Class Codes: B41J 2/04563 detecting head temperature; Ink temperature
• CPC Class Codes: B41J 2/0458 controlling heads based on heating elements forming bubbles
• CPC Class Codes: B41J 2/04581 controlling heads based on piezoelectric elements
• CPC Class Codes: B41J 2/04591 Width of the driving signal being adjusted
• CPC Class Codes: B41J 2202/17 Readable information on the head

Abstract

A temperature control system for an inkjet printhead assembly includes a printhead assembly having ink ejection elements energizable by an electrical pulse having an amplitude and pulse width, a sensor coupled to the printhead assembly for generating a signal representative of a printhead temperature. A controller reads a nominal operating pulse width, pulse width calibration data and the signal from the sensor. The controller calculates an adjusted pulse width using the nominal operating pulse width, the pulse width calibration data and the signal from the sensor. The controller uses the adjusted pulse width to control the printhead temperature.

Claims

1. A temperature control system for an inkjet printhead assembly, comprising:

a printhead assembly having ink ejection elements energizable by an electrical pulse having an amplitude and pulse width;

a sensor coupled to the printhead assembly for generating a signal representative of the printhead temperature;

a controller which reads a nominal operating pulse width, pulse width calibration data and the signal from the sensor;

said controller calculates an adjusted pulse width using the nominal operating pulse width, the pulse width calibration data and the signal from the sensor;

wherein the controller uses the adjusted pulse width to control printhead temperature.

2. The temperature control system of claim 1 wherein the controller is located on the printhead assembly.

3. The temperature control system of claim 1 wherein the controller is not located on the printhead.

4. The temperature control system of claim 1 wherein the controller reads the nominal operating pulse width and the pulse width calibration data from a memory located on the printhead assembly.

5. The temperature control system of claim 1 wherein the controller reads the nominal operating pulse width and the pulse width calibration data from a memory not located on the printhead.

6. The temperature control system of claim 1 wherein the temperature sensor is an analog temperature sensor.

7. The temperature control system of claim 6 further including an analog to digital converter for generating a digital word representing the measured analog signal.

8. The temperature control system of claim 1 wherein the temperature sensor is a digital temperature sensor.

9. The temperature control system of claim 1 wherein the temperature sensor includes multiple sensors distributed around the printhead so as to provide a global measurement of the printhead temperature.

10. The temperature control system of claim 1 wherein the pulse width calibration data is in a form of an equation.

11. The temperature control system of claim 1 wherein the pulse width calibration data is in a look-up table.

12. A method of controlling a temperature of an inkjet printhead comprising:

providing a printhead assembly having ink ejection elements energizable by an electrical pulse having an amplitude and pulse width;

reading a nominal printhead operating temperature, a nominal operating pulse width and pulse width calibration data;

obtaining a current printhead operating temperature using a sensor on the printhead;

determining a pulse width adjustment factor based on the pulse width calibration data and a measured temperature of the printhead;

calculating an adjusted operating pulse width based on the pulse width adjustment factor and the nominal operating pulse width; and

applying the adjusted operating pulse width to the printhead to control the printhead temperature.

13. The method of controlling the temperature of claim 12 wherein the controller is located on the printhead.

14. The method of controlling the temperature of claim 12 wherein the controller is not located on the printhead.

15. The method of controlling the temperature of claim 12 wherein the controller reads the nominal operating pulse width and the pulse width calibration data from a memory located on the printhead assembly.

16. The method of controlling the temperature of claim 12 wherein the controller reads the nominal operating pulse width and the pulse width calibration data from a memory not located on the printhead.

17. The method of controlling the temperature of claim 12 wherein the temperature sensor is an analog temperature sensor.

18. The method of controlling the temperature of claim 17 further including an analog to digital converter for generating a digital word representing a measured analog signal.

19. The method of controlling the temperature of claim 12 wherein the temperature sensor is a digital temperature sensor.

20. The method of controlling the temperature of claim 12 wherein the temperature sensor includes multiple sensors distributed around the printhead so as to provide a global measurement of the printhead temperature.

21. The method of controlling the temperature of claim 12 wherein the pulse width calibration data is in a form of an equation.

22. The method of controlling the temperature of claim 12 wherein the pulse width calibration data is in a look-up table.