Ink level detection in a pressure regulated pen

• US 5,583,545 A
• Filed: 10/31/1994
• Issued: 12/10/1996
• Est. Priority Date: 10/31/1994
• Status: Expired due to Term

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Hewlett-Packard Company (HP Inc.)
• Inventors: Elgee, Steven B., Hauck, Mark, Pawlowski, Norman E. Jr., Gast, Paul D., Cowger, Bruce
• Primary Examiner(s): Fuller, Benjamin R.
• Assistant Examiner(s): HALLACHER, CRAIG ALAN
• Application Number:
  US08/331,453
• Time in Patent Office: 771 Days
• Field of Search: 347/7, 347/85, 347/87, 347/86, 73/299, 73/302, 137/393
• US Class Current: 347/7
• CPC Class Codes: B41J 2/175 Ink supply systems ; Circuit parts therefor
• CPC Class Codes: B41J 2/17513 Inner structure
• CPC Class Codes: B41J 2/17523 Ink connection
• CPC Class Codes: B41J 2/17553 Outer structure
• CPC Class Codes: B41J 2/17556 Means for regulating the pressure in the cartridge
• CPC Class Codes: B41J 2/17566 Ink level or ink residue control
• CPC Class Codes: B41J 2/17596 Ink pumps, ink valves
• CPC Class Codes: G01F 23/003 with a probe suspended by rotatable arms with floats G01F23/32
• CPC Class Codes: G01F 23/72 using magnetically actuated indicating means

Abstract

The present invention relates to Ink Level Detection in a Pressure Regulated Pen. A liquid level detector for a liquid containment device, such as an ink-jet pen, provides a signal indicative of a lowering level of liquid in the containment device. In exemplary embodiments, a refillable or replaceable ink reservoir supplies ink to the printhead of the pen under pressure. Electrical or electromagnetic devices are used individually or in combination with a pressure regulator apparatus to sense a back pressure in the containment device after the reservoir has gone dry to trigger a signal indicating a low or out-of-ink condition.

Claims

1. A level sensing device for a fluid containment chamber having a fluid inlet and a fluid outlet, said fluid inlet coupling said containment chamber to a reservoir having a supply of fluid, comprising:

controlling means for controlling flow of fluid through said containment chamber and for regulating fluid pressure within said containment chamber such that said chamber is substantially filled with fluid via said controlling means as long as a supply of fluid remains in said reservoir;

moving means, operatively combined with said controlling means, for moving said controlling means to a predetermined position as said containment chamber is drained of fluid following depletion of said supply of fluid in said reservoir; and

detecting means, cooperative with said controlling means, for providing a signal indicative of said controlling means reaching said predetermined position, wherein said controlling means has a lever with a magnet fixed thereon which moves from an inlet closed position to said predetermined position where said magnet interacts with said detecting means.

2. The device as set forth in claim 1, wherein said controlling means further comprises:

activating means adapted to close an electrical circuit for activating said detecting means.

3. The device as set forth in claim 1, wherein said controlling means further comprises:

activating means adapted to open an electrical circuit for activating said detecting means.

4. The device as set forth in claim 1, wherein said detecting means further comprises:

a Hall-effect sensor.

5. The device as set forth in claim 4, wherein said Hall-effect sensor is adapted to provide signals indicative of said closed position, said predetermined position, and at least one intermediary position.

6. The device as set forth in claim 1, wherein said moving means further comprises:

an inflatable member, adjacent said controlling means, adapted to inflate under ambient atmospheric pressure against said controlling means as said containment chamber is drained of fluid following depletion of said supply of fluid in said reservoir.

7. A fluid level sensing device for a fluid pressure regulated containment chamber, having a valve actuating means adapted for motion dependent upon fluid pressure level in said containment chamber to control ingress of fluid from a fluid supply, comprising:

means, cooperatively combined with said valve actuating means, for sensing depletion of fluid in said containment chamber and for moving said valve actuating means based upon a negative pressure condition in said containment chamber in response to a lack of a positive pressure level in said containment chamber due to lack of available fluid from said fluid supply;

detecting means for detecting when said valve actuating means has reached at least one predetermined position within said containment chamber, wherein said detecting means is affixed to said means for sensing and for moving; and

indicating means, cooperative with said detecting means, for providing a signal indicative that said detecting means has achieved said predetermined position.

8. The device as set forth in claim 7, wherein said pressure sensing means further comprises:

an inflatable bag member, and

venting means for venting said bag member to ambient atmospheric pressure, whereby said inflatable bag member inflates when a negative pressure condition exists within said containment chamber.

9. The device as set forth in claim 7, wherein said detecting means comprises:

means for closing an electrical circuit such that said indicating means provides said signal.

10. The device as set forth in claim 7, wherein said detecting means comprises:

means for opening an electrical circuit such that said indicating means provides said signal.

11. The device as set forth in claim 7, wherein said detecting means comprises:

a magnet fixedly mounted on said valve actuating means.

12. The device as set forth in claim 11, wherein said indicating means comprises:

a Hall-effect sensor adapted for predetermined positioning with respect to said valve actuating means.

13. An ink level detection apparatus for a pen system, having a pen body, an ink reservoir and means for controlling the flow of ink from said ink reservoir into said pen body, comprising:

means for regulating fluid pressure within said pen body integrated with said device for controlling the flow of ink form said ink reservoir into said pen body;

moving means, operative combined with said means for regulating, for moving said means for controlling from a relative position for controlling flow of ink from said reservoir into said pen body to at least one predetermined other position as said pen body is depleted of ink; and

detecting means, mounted with respect to said pen body, for detecting when said means for controlling has moved to said at least one predetermined other position.

14. The apparatus as set forth in claim 13, further comprising:

said means for regulating is a valve lever adapted to regulate ink flow from said reservoir into said pen body by selectively opening and closing a valve controlling said ink flow based upon fluid pressure level within said pen body; and

said moving means includes a fitment for mounting said means for regulating within said pen body and an inflatable bag member, fixedly mounted on said fitment adjacent said means for regulating, having a vent to ambient atmospheric pressure such that said bag member inflates under influence of said ambient atmospheric pressure as said fluid pressure level falls beyond a predetermined level.

15. The apparatus as set forth in claim 14, wherein said detecting means comprises:

a magnet fixedly mounted on said means for regulating; and

a Hall-effect sensor fixedly mounted with respect to said pen body such that change of relative position of said magnet within said pen body is detected by said Hall-effect sensor.

16. The apparatus as set forth in claim 13, wherein said detecting means comprises:

electrical circuitry for providing a signal indicative of said means for regulating being located at said at least one predetermined other position; and

circuit breaker means, integrated with said means for regulating, for opening and closing electrical contact through said electrical circuitry.

17. A pressure regulated ink-jet pen system comprising:

a replenishable ink supply;

a pen body having a printhead;

a liquid ink containment chamber within said pen body;

a valve coupling said containment chamber to said pressurized replenishable ink supply;

a valve actuator device adapted for motion dependent upon a predetermined positive pressure level of ink in said containment chamber to control ingress of ink from said ink supply into said containment chamber; and

an ink level sensing device, including pressure sensing means, operatively vented to ambient atmospheric pressure and combined with said valve actuator device for sensing a drop in pressure within said containment chamber below said ambient atmospheric pressure and for moving said valve actuator device to at least one predetermined position in response to said send drop in pressure; and

detecting means, operatively associated with said valve actuator means device, for providing a signal representative of said valve actuator device having reached a predetermined position.

18. The system as set forth in claim 17, wherein said detecting means comprises:

electrical circuitry wherein said valve actuator includes a selective circuit breaker.

19. The system as set forth in claim 17, wherein said detecting means comprises:

a magnet fixedly mounted on said valve actuator for motion from a predetermined position when said containment chamber is filled with ink through a series of predetermined positions representative of lowering levels of ink, including an out-of-ink condition position; and

a Hall-effect sensor fixedly mounted with respect to said valve actuator such that each of said predetermined positions is detected.

20. An out-of-ink condition signal generator for an ink-jet pen system having a pressurized ink reservoir containing a depletable supply of ink therein, a pen body having an ink chamber, a printhead mechanism, and a pressure regulator coupling said ink reservoir with said ink chamber to transfer ink from said ink reservoir to said ink chamber, comprising:

electrical means for providing a signal indicating an out-of-ink condition in said system;

a pressure sensing device mounted within said pen body ink chamber;

fitment means for coupling said pressure sensing device to said pressure regulator, having a vent that subjects said pressure sensing device to ambient atmospheric pressure such that a drop in pressure in said ink chamber below ambient atmospheric pressure causes said pressure sensing device to move said pressure regulator to a predetermined position; and

circuit breaker means operatively attached to said pressure regulator for selectively making and braking continuity of said electrical means when said pressure regulator is at or off said predetermined position, respectively.

21. An out-of-ink condition signal generator for an ink-jet pen system having a pressurized ink reservoir containing a depletable supply of ink therein, a pen body having an ink chamber, a printhead mechanism, and a pressure regulator coupling said ink reservoir with said ink chamber to transfer ink from said ink reservoir to said ink chamber, comprising:

a magnet fixedly mounted to said pressure regulator;

a pressure sensing device mounted within said pen body ink chamber;

fitment means for coupling said pressure sensing device to said pressure regulator, having a vent that subjects said pressure sensing device to ambient atmospheric pressure such that a drop in pressure in said ink chamber below ambient atmospheric pressure causes said pressure sensing device to move said pressure regulator to a predetermined position; and

a Hall-effect sensor fixedly mounted in said system with respect to said pressure regulator for detecting when said pressure regulator has reached said predetermined position.

22. An out-of-ink condition signal generator for an ink-jet pen system having a pressurized ink reservoir containing a depletable supply of ink therein, a pen body having an ink chamber, a printhead mechanism, and a pressure regulator coupling said ink reservoir with said ink chamber to transfer ink from said ink reservoir to said ink chamber, comprising:

electrical circuit means for providing a signal indicating an out-of-ink condition in said system;

a pressure sensing device mounted within said pen body ink chamber and having a first predetermined shape;

fitment means for coupling said pressure sensing device to said pressure regulator, having a vent that subjects said pressure sensing device to ambient atmospheric pressure such that a drop in pressure in said ink chamber below ambient atmospheric pressure causes said pressure sensing device to move said pressure regulator to a predetermined position; and

circuit breaker means, within said pressure sensing device, for breaking electrical continuity for said electrical circuit means when said pressure regulator has changed to said second predetermined shape.