Claims
- 1. An accumulator apparatus comprising:
- an expandable and contractible bag;
- mounting means for mounting the bag within a fluid volume of a particular size so that expansion of the bag decreases the size of the fluid volume, the bag including an opening arranged so that an interior of the bag is in communication with ambient air outside the fluid volume; and
- a spring disposed within the fluid volume and having a first portion that assumes a curved relaxed state, part of the bag being adjacent to one side of the curved first portion, the bag part being urged by the spring to be substantially fully contracted when the spring first portion is in the relaxed state.
- 2. The apparatus of claim I wherein the first portion of the spring has a convex surface whenever the first portion is in a relaxed state, the bag part being adjacent to the convex surface.
- 3. The apparatus of claim 1 wherein the spring has a flat base connected to the first portion of the spring.
- 4. The apparatus of claim 3 wherein the spring includes a second portion connected to the base, the second portion assuming a curved relaxed state, another part of the bag being disposed adjacent to one side of the second portion and to one side of the base of the spring.
- 5. The apparatus of claim 1 wherein the spring includes a second portion that assumes a curved relaxed state, another part of the bag being disposed adjacent to one side of the curved second portion.
- 6. The apparatus of claim 1 wherein the spring is stainless steel.
- 7. The apparatus of claim 1 wherein the spring has a thickness of about 75 microns and a yield strength greater than about 5,600 Kg/cm.sup.2.
- 8. An accumulator apparatus comprising:
- an expandable and contractible bag;
- mounting means for mounting the bag within a fluid volume of a particular size so that expansion of the bag decreases the size of the fluid volume, the bag including an opening mounted so that an interior of the bag is in continuous communication with ambient air outside the fluid volume, wherein the bag is formed of flexible material and is contractible into a generally flat configuration and
- wherein the fluid volume is defined by a reservoir, the reservoir being sealed and containing ink therein under a back pressure, the back pressure being present irrespective of whether the bag is expanded or contracted.
- 9. The accumulator apparatus of claim 8 further comprising a print head connected to the reservoir for ejecting drops of ink from the reservoir.
- 10. The apparatus of claim 8 wherein the bag comprises sheets formed of heat-weldable material.
- 11. The apparatus of claim 9 wherein the bag sheets include a film of air-impermeable material attached thereto for rendering the bag substantially impermeable to air.
- 12. An accumulator for an ink-jet pen that has a substantially sealed reservoir volume, comprising:
- a spring; and
- an expandable and contractible bag attached to one side of the spring, the spring and bag being positionable within the reservoir volume, the bag including an opening arranged so that an interior of the bag is in communication with ambient air outside of the reservoir volume, the bag and spring being attached adjacent one another so that the bag expands to deflect the spring as fluid pressure inside the reservoir volume decreases relative to pressure of the ambient air outside of the reservoir volume.
- 13. The accumulator of claim 12 further comprising print head means for ejecting ink drops from the reservoir volume.
- 14. The accumulator of claim 12 wherein the spring contracts the bag as fluid pressure outside the reservoir volume decreases relative to fluid pressure inside the reservoir.
- 15. The apparatus of claim 12 wherein the spring includes a first portion that assumes a curved relaxed state, the bag being attached to one side of the curved first portion.
- 16. The apparatus of claim 15 wherein the first portion of the spring has a convex surface whenever the first portion is in a relaxed state, the bag being attached to the convex surface.
- 17. The apparatus of claim 12 wherein the spring is metal and the bag is formed of flexible material having a plastic outer surface.
- 18. An accumulator apparatus comprising:
- a sealed reservoir for containing ink and having a back pressure established therein;
- an expandable and contractible bag mounted within the reservoir, the bag having an opening therein arranged so that an interior of the bag is in communication with ambient air outside of the reservoir, the bag being arranged so that contraction of the bag increases back pressure in the reservoir; and
- a print head mounted to the reservoir and adapted for ejecting ink drops from the reservoir.
- 19. The apparatus of claim 18, further comprising a spring disposed adjacent to the bag and arranged to urge contraction of the bag for increasing the reservoir back pressure.
- 20. The apparatus of claim 19 wherein the spring and bag are configured and arranged so that the bag is substantially fully contracted when the spring is in a relaxed state.
- 21. The apparatus of claim 19 wherein the bag is attached to the spring by a fitment, and the spring includes a plurality of access holes formed therein, the bag being attached to the fitment through the access holes.
- 22. The apparatus of claim 21 wherein the fitment includes other access holes for attaching the bag to said bag through the other access holes.
- 23. A method for making an accumulator apparatus, comprising the steps of:
- attaching an expandable and contractible bag to a spring so that when the spring is in a relaxed state the bag will be substantially contracted;
- configuring the bag and spring so that the bag will expand and deflect the spring whenever a pressure difference between the fluid inside and outside of the bag exceeds a predetermined minimum level; and
- supporting the bag and spring to maintain the interior of the bag in fluid communication with fluid outside of the bag thereby to define an unobstructed path for fluid movement into and out of the bag.
- 24. The method of claim 23 wherein the configuring step includes the substep of shaping the spring to have a curved portion when in a relaxed state.
- 25. The method of claim 24 wherein the attaching step includes the substep of fastening the bag to the curved portion of the spring.
- 26. The method of claim 23 wherein the spring is metal and wherein the bag has a plastic outer surface, the attaching step including the substep of forming access holes in the spring for providing locations for attaching the bag to the spring.
- 27. The method of claim 23 wherein the accumulator is to be disposed within a fluid volume that may be subjected to a decrease in pressure, the configuring step including the step of sizing the bag to define a working volume that is equal to or greater than a change in the fluid volume attributable to the decrease in pressure.
- 28. An accumulator apparatus for an ink reservoir of a pen comprising:
- an elongated spring member mounted inside the reservoir and shaped to resile to a relaxed state and to resist deflection out of the relaxed state;
- an expandable and contractable bag mounted along the length of the spring member so that expansion of the bag deflects the spring member and so that contraction of the bag permits the spring member to resile toward the relaxed state; and
- shaping means for reducing along only a portion of the length of the spring member the resistance of the spring member to deflection caused by bag expansion.
- 29. The apparatus of claim 28 wherein the elongated spring member has a longitudinal centerline and an end and a middle portion away from the end, and wherein the first portion of the spring member is located away from the middle portion of the spring member.
- 30. The apparatus of claim 29 wherein the first portion of the spring member has an array of apertures formed therein for reducing the resistance of the spring member to deflection.
- 31. The apparatus of claim 30 wherein the first portion of the spring member is located adjacent to the end of the spring member.
- 32. The apparatus of claim 30 wherein the first portion is located on opposite sides of the middle portion of the spring member.
- 33. The apparatus of claim 30 wherein the spring member is constructed with the array of apertures shaped to reduce the mass of the spring member near the longitudinal centerline by an amount greater than the amount of mass reduced by the apertures away from the longitudinal centerline of the spring member.
- 34. The apparatus of claim 33 wherein the first portion of the spring member is located adjacent to the end of the spring member.
- 35. The apparatus of claim 33 wherein the first portion is located on opposite sides of the middle portion of the spring member.
- 36. The apparatus of claim 30 wherein the spring member is constructed with the array of apertures shaped to reduce the mass of the spring member near the end of the spring member by an amount greater than the amount of mass reduced by the apertures away from the end of the spring member.
- 37. The apparatus of claim 36 wherein the first portion of the spring member is located adjacent to the end of the spring member.
- 38. The apparatus of claim 30 wherein the spring member is configured to include a slit formed along the longitudinal centerline of the spring member to extend substantially continuously from the end of the spring member through the middle portion of the spring member.
- 39. The apparatus of claim 30 wherein the spring member is configured to include a plurality of spaced apart slits extending along the length of the spring member.
- 40. The apparatus of claim 28 wherein the first portion of the spring member is thinner than the remaining portion of the spring member.
Parent Case Info
This is a continuation-in-part of application Ser. No. 07/464,258, filed Jan. 12, 1990, now abandoned.
US Referenced Citations (30)
Foreign Referenced Citations (6)
Number |
Date |
Country |
0375388 |
Jun 1990 |
EPX |
2742633 |
Apr 1979 |
DEX |
56-92072 |
Jul 1981 |
JPX |
59-232872 |
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JPX |
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Continuation in Parts (1)
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Number |
Date |
Country |
Parent |
464258 |
Jan 1990 |
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