Leak detection for an ink container

• US 6,467,861 B1
• Filed: 05/17/2000
• Issued: 10/22/2002
• Est. Priority Date: 09/01/1998
• Status: Expired due to Term

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Hewlett-Packard Company (HP Inc.)
• Inventors: Wilson, Rhonda L., Haines, Paul Mark, DeVries, Mark A., Thielman, Jeffrey L.
• Primary Examiner(s): Pham, Hai
• Assistant Examiner(s): Huffman, Julian D.
• Application Number:
  US09/574,691
• Time in Patent Office: 888 Days
• Field of Search: 347/6, 347/7, 347/84, 347/85, 347/89, 347/19, 73/37, 73/378, 73/40, 73/405
• US Class Current: 347/6
• CPC Class Codes: B41J 2/175 Ink supply systems ; Circuit parts therefor

Abstract

An inkjet printing system includes an ink container adapted to hold a supply of liquid ink therein and a printhead communicating with the supply of liquid ink via a flow path. A pressure sensor measures a pressure of liquid ink disposed in the flow path and a volume detector detects a volume of liquid ink delivered through the flow path. In addition, a leak indicator communicates with the pressure sensor and the volume detector, and indicates an ink container leak based on the pressure of liquid ink disposed in the flow path and the volume of liquid ink delivered through the flow path.

Claims

1. A printing system, comprising:

a printhead;

an ink container communicating with and supplying liquid ink to the printhead, the printhead adapted to eject drops of the liquid ink during printing; and

a leak indicator communicating with and indicating an ink container leak based on a pressure of liquid ink supplied to the printhead and a volume of liquid ink supplied to the printhead.

2. The printing system of claim 1, wherein the leak indicator indicates the ink container leak when the pressure of liquid ink supplied to the printhead is less than a predetermined value and the volume of liquid ink supplied to the printhead is greater than a predetermined value.

3. The printing system of claim 1, wherein the volume of liquid ink supplied to the printhead is derived from a count of a number of drops of the liquid ink ejected from the printhead.

4. The printing system of claim 1, further comprising:

a pressurized source of gas communicating with and supplying pressurized gas to the ink container, the pressurized gas adapted to pressurize the ink container and expel liquid ink therefrom during printing, wherein the pressure of liquid ink supplied to the printhead is based on a differential pressure of liquid ink supplied to the printhead and pressurized gas supplied to the ink container.

5. A printing system, comprising:

an ink container adapted to hold a supply of liquid ink therein;

a first flow path communicating with the ink container and the supply of liquid ink;

a printhead communicating with the first flow path, the printhead adapted to eject drops of the liquid ink during printing;

a pressure sensor communicating with the first flow path and measuring a pressure of liquid ink disposed therein;

a volume detector communicating with the first flow path and detecting a volume of liquid ink delivered therethrough; and

a leak indicator communicating with the pressure sensor and the volume detector, the leak indicator indicating an ink container leak based on the pressure of liquid ink disposed in the first flow path and the volume of liquid ink delivered through the first flow path.

6. The printing system of claim 5, wherein the leak indicator indicates the ink container leak when the pressure of liquid ink disposed in the first flow path is less than a predetermined value and the volume of liquid ink delivered through the first flow path is greater than a predetermined value.

7. The printing system of claim 5, wherein the volume detector includes a drop counter communicating with the printhead, the drop counter adapted to count a number of drops of the liquid ink ejected from the printhead.

8. The printing system of claim 5, further comprising:

a second flow path communicating with the ink container; and

a pressurized source of gas communicating with the second flow path, the pressurized source of gas adapted to pressurize the ink container and expel liquid ink therefrom, wherein the pressure sensor further communicates with the second flow path and measures a pressure of gas disposed therein, and wherein the leak indicator indicates the ink container leak based on a differential pressure of liquid ink disposed in the first flow path and gas disposed in the second flow path, and the volume of liquid ink delivered through the first flow path.

9. The printing system of claim 8, wherein the ink container includes a housing defining an interior chamber adapted to hold the supply of liquid ink therein, wherein the supply of liquid ink defines an occupied portion and an unoccupied portion of the interior chamber, and wherein the first flow path communicates with the occupied portion of the interior chamber and the second flow path communicates with the unoccupied portion of the interior chamber.

10. The printing system of claim 9, wherein the ink container further includes a collapsible ink reservoir disposed within the interior chamber of the housing, wherein the collapsible ink reservoir is adapted to hold the supply of liquid ink therein, and wherein the first flow path communicates with the collapsible ink reservoir and the second flow path communicates with the interior chamber of housing.

11. A method of detecting an ink container leak of an ink container adapted to hold a supply of liquid ink therein, the method comprising the steps of:

pressurizing the ink container to expel liquid ink therefrom;

measuring a pressure of liquid ink expelled from the ink container;

measuring a volume of liquid ink expelled from the ink container; and

indicating the ink container leak based on the pressure of liquid ink expelled from the ink container and the volume of liquid ink expelled from the ink container.

12. The method of claim 11, wherein the step of indicating the ink container leak includes indicating the ink container leak when the pressure of liquid ink expelled from the ink container is less than a predetermined value and the volume of liquid ink expelled from the ink container is greater than a predetermined value.

13. The method of claim 11, wherein the step of measuring the pressure of liquid ink expelled from the ink container includes measuring a pressure differential between a pressure pressurizing the ink container and the pressure of liquid ink expelled from the ink container, and wherein the step of indicating the ink container leak includes indicating the ink container leak when the pressure differential is less than a predetermined value and the volume of liquid ink expelled from the ink container is greater than a predetermined value.

14. The method of claim 11, wherein the ink container is adapted to supply the liquid ink to a printhead, and wherein the step of measuring the volume of liquid ink expelled from the ink container includes counting ink drops ejected from the printhead during printing.

15. The method of claim 11, further comprising the step of:

discontinuing the step of pressurizing the ink container to expel liquid ink therefrom when the ink container leak is indicated.

16. The method of claim 11, wherein the ink container includes a collapsible reservoir disposed therein, wherein the collapsible reservoir is adapted to hold the supply of the liquid ink therein, and wherein the step of pressurizing the ink container to expel liquid ink therefrom includes applying pressure to the collapsible reservoir to expel liquid ink from the collapsible reservoir.

17. A printing system, comprising:

a housing having walls defining an interior chamber adapted to hold a supply of liquid ink therein, the supply of liquid ink defining an occupied portion and an unoccupied portion of the interior chamber;

a first flow path communicating with the occupied portion of the interior chamber of the housing and communicating externally of the housing, the first flow path adapted to deliver liquid ink therethrough;

a second flow path communicating with the unoccupied portion of the interior chamber of the housing and communicating externally of the housing, the second flow path adapted to deliver pressurized gas therethrough to the unoccupied portion of the interior chamber of the housing; and

a pressure sensor communicating with the first flow path and adapted to measure a pressure of liquid ink delivered therethrough, and wherein the pressure sensor further communicates with the second flow path and is adapted to measure a pressure of pressurized gas delivered therethrough.

18. A printing system, comprising:

a housing having walls defining an interior chamber adapted to hold a supply of liquid ink therein, the supply of liquid ink defining an occupied portion and an unoccupied portion of the interior chamber;

a first flow path communicating with the occupied portion of the interior chamber of the housing and communicating externally of the housing, the first flow path adapted to deliver liquid ink therethrough;

a second flow path communicating with the unoccupied portion of the interior chamber of the housing and communicating externally of the housing, the second flow path adapted to deliver pressurized gas therethrough to the unoccupied portion of the interior chamber of the housing; and

a pressure sensor communicating with the first flow path and adapted to measure a pressure of liquid ink delivered therethrough;

a volume detector communicating with the first flow path and detecting a volume of liquid ink delivered therethrough; and

a leak indicator communicating with the pressure sensor and the volume detector, the leak indicator indicating an ink container leak based on the pressure of liquid ink delivered through the first flow path and the volume of liquid ink delivered through the first flow path.

19. The printing system of claim 18, wherein the leak indicator indicates the ink container leak when the pressure of liquid ink delivered through the first flow path is less than a predetermined value and the volume of liquid ink delivered through the first flow path is greater than a predetermined value.

20. A printing system, comprising:

a housing defining an interior chamber;

a collapsible reservoir disposed within the interior chamber of the housing, the collapsible reservoir adapted to hold a supply of liquid ink therein;

a first flow path communicating with the collapsible reservoir and communicating externally of the housing, the first flow path adapted to deliver liquid ink therethrough;

a second flow path communicating with the interior chamber of the housing and communicating externally of the housing, the second flow path adapted to receive pressurized gas therethrough; and

a pressure sensor communicating with the first flow path and adapted to measure a pressure of liquid ink delivered therethrough, and wherein the pressure sensor further communicates with the second flow path and is adapted to measure a pressure of pressurized gas received therethrough.

21. A printing system, comprising:

a housing defining an interior chamber;

a collapsible reservoir disposed within the interior chamber of the housing, the collapsible reservoir adapted to hold a supply of liquid ink therein;

a first flow path communicating with the collapsible reservoir and communicating externally of the housing, the first flow path adapted to deliver liquid ink therethrough;

a second flow path communicating with the interior chamber of the housing and communicating externally of the housing, the second flow path adapted to receive pressurized gas therethrough; and

a pressure sensor communicating with the first flow path and adapted to measure a pressure of liquid ink delivered therethrough

a volume detector communicating with the first flow path and detecting

a volume of liquid ink delivered therethrough; and

a leak indicator communicating with the pressure sensor and the volume detector, the leak indicator indicating an ink container leak based on the pressure of liquid ink delivered through the first flow path and the volume of liquid ink delivered through the first flow path.

22. The printing system of claim 21, wherein the leak indicator indicates the ink container leak when the pressure of liquid ink delivered through the first flow path is less than a predetermined value and the volume of liquid ink delivered through the first flow path is greater than a predetermined value.