Apparatus for providing ink to an ink-jet print head and for compensating for entrapped air

• US 5,872,584 A
• Filed: 10/31/1995
• Issued: 02/16/1999
• 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: Hauck, Mark, Pawlowski, Norman E. Jr.
• Primary Examiner(s): Metjahic, Safet
• Assistant Examiner(s): Chizmar, John
• Application Number:
  US08/550,902
• Time in Patent Office: 1,204 Days
• Field of Search: 347/7, 347/85, 347/86, 347/87
• US Class Current: 347/86
• CPC Class Codes: B41J 2/175 Ink supply systems ; Circuit parts therefor
• CPC Class Codes: B41J 2/17503 Ink cartridges
• 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: B41J 2002/17516 comprising a collapsible ink holder, e.g. a flexible bag
• 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

Apparatus for providing ink to an ink-jet print head in a print cartridge at substantially constant pressure and for compensating for air within the print cartridge. A flexible bag is maintained at atmospheric pressure within the print cartridge and actuates a pressure regulator also within the print cartridge. By expanding and contracting, the bag compensates for changes in pressure and temperature that occur while the pressure regulator is shut and that affect air entrapped within the print cartridge.

Claims

1. A back pressure regulator device for a ink-jet printing apparatus having an ink-jet print head within a print cartridge, and an ink plenum within the print cartridge in fluid communication with the print head, the device comprising:

means for providing ink to the print head at substantially constant back pressure and for compensating for air within the print cartridge, including

a pressure regulator means in fluid communication with the ink plenum for supplying ink to the print head at substantially constant pressure;

a flexible bag within the ink plenum maintained at an internal reference pressure, said bag compensates for air within the print cartridge; and

an actuator means for the back pressure regulator device and connected to said pressure regulator means, said bag directly bears against said actuator means and thereby actuates said pressure regulator device.

2. The apparatus of claim 1 further comprising:

urging means, operatively connected to the bag, for urging the bag against said internal reference pressure, thereby increasing said bag'"'"'s compensation for air within the print cartridge.

3. The apparatus of claim 2 wherein said urging means is an accumulator actuator that applies a substantially constant force against the reference pressure within said bag.

4. The apparatus of claim 1 further comprising:

valve means adapted for coupling said pressure regulator device to a supply of ink, wherein the actuator means engages said valve, said valve having a resiliently deformable valve seat such that said actuator, valve, and valve seat compensate for air within the print cartridge.

5. Apparatus for providing ink to an ink-jet print head in a print cartridge at substantially constant pressure and for compensating for air within the print cartridge, comprising:

an ink-jet print head within a print cartridge;

an ink plenum within the print cartridge in fluid communication with the print head ;

a pressure regulator in fluid communication with the ink plenum for supplying ink to the print head at substantially constant pressure;

an expandable/contractible bag within the ink plenum, said bag having two lungs maintained at an internal reference pressure and with a common axis of expansion/contraction, said lungs are coupled to communicate with each other and compensate for air within the print cartridge, wherein said axis of expansion/contraction is substantially defined by a region of coupling of said lungs; and

a pressure regulator actuating lever means for actuating the pressure regulator and connected thereto, said lever directly bears against said lungs and thereby actuates said pressure regulator, said lever means having an axis of rotation parallel with said axis of expansion/contraction of the lungs so that said lever means tracks any expansion/contraction of the lungs.

6. The apparatus of claim 5 further comprising:

an accumulator lever means for applying a substantially constant force against the reference pressure in the lungs, said accumulator lever means having a axis of rotation parallel with said axis of expansion/contraction of the lungs so that said accumulator lever means tracks any expansion/contraction of the lungs.

7. The apparatus of claim 5 wherein one lung has a region of enhanced sensitivity to differential pressure across said region and said region bears against the pressure regulator actuating lever means.

8. The apparatus of claim 6 wherein one lung has a region of enhanced sensitivity to differential pressure across said region and said region bears against the accumulator lever means.

9. The apparatus of claim 6 wherein each lung has a region of enhanced sensitivity to differential pressure across said region and each of said regions bears against an adjacent lever means.

10. The apparatus of claim 5 wherein each lung has a region of enhanced sensitivity to differential pressure across said region and each of said regions bears against the other region.

11. Ink-jet printing apparatus, comprising:

a remote ink reservoir containing ink under a pressure of P1;

an ink-jet print heads;

an ink plenum in fluid communication with the print heads;

a conduit for ink selectively connecting the remote reservoir and the plenum;

a pressure regulator in fluid communication with the ink plenum and connectable thereto for supplying ink to the print head at a substantially constant back pressure of P2, where P1 is substantially greater than P2;

a predetermined area within the print cartridge to collect air;

an expandable/contractible bag within the ink plenum maintained at an internal reference pressure, said bag being in fluid communication with the predetermined air collection area and compensates for air within the print cartridge; and

an actuator for the pressure regulator and connected thereto, said bag directly bears against said actuator and thereby actuates said pressure regulator.

12. The apparatus as set forth in claim 11, said remote reservoir further comprising:

a replaceable ink reservoir.

13. The apparatus as set forth in claim 11, said remote reservoir further comprising:

an ink reservoir refillable with a supply of ink.

14. The apparatus as set forth in claim 11, said remote reservoir further comprising:

a flaccid bag pressurized to a predetermine level.

15. The apparatus as set forth in claim 11, further comprising:

said actuator is a first lever having a range of motion limited by engagement with a first inner wall of said print cartridge; and

said regulator is a second lever having a range of motion limited by engagement with a second inner wall of said print cartridge, such that said first lever engages said first inner wall prior to said second lever engaging said second inner wall of said print cartridge.

16. An ink-jet hard copy apparatus, comprising:

a mechanism for moving print media through said printer;

at least one ink supply, said ink supply being adapted to be replaced or filled;

at least one conduit coupled to said ink supply;

at least one print cartridge;

a mechanism for scanning said cartridge with respect to a print medium positioned adjacently to said cartridge by said mechanism for moving print media through said printer;

each said at least one print cartridge having

a substantially sealed housing, said housing having an ink inlet port for coupling said conduit to said cartridge,

at least one ink accumulator chamber within said housing,

at least one print head fluidically coupled to said at least one ink accumulator chamber for receiving ink therefrom,

an ink flow and pressure control mechanism mounted within said ink accumulator chamber, said ink flow and pressure control mechanism including

a valve mechanism coupled to said ink inlet port,

an expandible and contractible bag, said bag having a vent to ambient atmospheric pressure,

a print head back pressure regulator,

an actuator,

wherein said pressure regulator and said actuator are coupled with a biased coupling tending to force said regulator and said actuator together such that a predetermined back pressure is substantially maintained at said print head and flow of ink through said valve mechanism is controlled as a function of expansion and contraction of said bag with respect to ambient atmospheric pressure against said biased coupling and a differential between a bias exerted by said biased coupling and ambient atmospheric pressure.

17. A method for delivering ink to a ink-jet pen, having a print head operating at a gauged predetermined negative pressure comprising the steps of:

providing a supply of ink in a positive pressure container;

controlling both flow of ink from said supply into said pen and said negative pressure simultaneously via balancing ambient atmospheric pressure in at least one lung mechanism within said pen against a positive bias acting to compress a pair of negative pressure control, ink flow control valving mechanisms within said pen.

18. The method as set forth in claim 17, said step of providing a supply of ink further comprising the steps of:

supplying a quantity of ink in a replenishable, flaccid bag.

19. An ink-jet pen, comprising:

a housing having an ink accumulator having an ink inlet port adapted to be coupled to a supply of ink;

a valve mounted at said port;

a ink-jet print head in fluidic communication with said ink accumulator;

a pressure regulator;

an actuator;

said regulator and actuator are coupled with a bias mounted to cause a force tending to move said regulator and said actuator together;

a counter bias acting against said bias as a function of ambient atmospheric pressure,

wherein a substantially constant negative pressure is maintained at said print head and flow of ink from said supply through said valve is controlled via a balance of said force and ambient atmospheric pressure.

20. The pen as set forth in claim 19, said supply of ink further comprising:

a pressurizable container having a replaceable or refillable supply of ink therein.

21. The pen as set forth in claim 19, further comprising:

said print head has a plurality of ink-jet nozzles,

said actuator and said regulator include a pair of levers, biased to create said substantially constant negative pressure as a predetermined back pressure to inhibit drooling from said nozzles, at least one of said levers carrying a valve seat of said valve such that motion of said levers controls flow of ink through said valve.