GB2368557A

GB2368557A - Ink cartridge including a float valve disposed in the ink outlet chamber thereof

Info

Publication number: GB2368557A
Application number: GB0026867A
Authority: GB
Inventors: Clive Drake
Original assignee: OPPORTUNITY EUROP LIMIMTED
Current assignee: OPPORTUNITY EUROP LIMIMTED
Priority date: 2000-11-03
Filing date: 2000-11-03
Publication date: 2002-05-08
Also published as: GB0026867D0

Abstract

An ink cartridge for an inkjet printer includes a main chamber 10, an ink outlet chamber 19, and a conical float valve 27 formed from a low density plastic, e.g. polyethylene, disposed within the ink outlet chamber. The valve is movable between upper and lower limiting positions to control the flow of ink from the main chamber to the outlet chamber. The valve may be provided with a spike 30 which acts a guide thereto and also reduces the rate of ink flow through an opening 18. The cartridge may include an internal fin 17 or buoyant film (32,Fig.3) to reduce swirling or sloshing of the ink within the main chamber. The shape of the valve may be varied, for example, a sphere (30,Fig.3), or a hinged door/gate (33,Fig.4). The arrangement may be modified such that the ink is contained within a flexible, metallised foil bag (35,Fig.5), which removes the need for the fin or buoyant film.

Description

INK CARTRIDGES Field of the Invention This invention relates to ink cartridges for printers, particularly inkjet printers.

Many ink cartridges currently include a main chamber within which the ink is stored, an ink outlet chamber and a sponge or other porous member interposed between the ink outlet chamber and the main chamber and/or controlling the outflow of ink from the ink outlet chamber.

It is an object of the present invention to provide an ink cartridge which includes improved means for controlling the egress of the ink from the main chamber.

In particular, it is an object of the present invention to provide an ink cartridge which does not include a sponge or other porous member for controlling the egress of the ink from the main chamber. Summary of the Invention According to the present invention there is provided an ink cartridge which includes a main chamber within which the ink is stored, an ink outlet chamber and a float valve controlling the passage of ink from the main chamber to the ink outlet chamber.

The ink outlet chamber is preferably contained within an extension projecting downwardly from the base of the main chamber and the float valve is preferably arranged to control the flow of ink through an opening in the base of the main chamber into the ink outlet chamber.

The base of the main chamber may be inclined, with the opening in the base at the lowermost part of the base, so that the ink drains downwardly to said opening, which communicates with the ink outlet chamber.

The ink may be stored in the main chamber itself, but may alternatively be stored in a flexible bag contained within the main chamber. The flexible bag may be a metallised foil bag.

The float valve may comprise a float element formed of a low density plastics material, for example, low density polyethylene or polystyrene having a specific gravity less than 0.2.

The float element may have an upper surface of conical form which, when the float valve is in its uppermost position, is arranged to have sealing engagement with a complementary conical seating defined by the upper wall of the ink outlet chamber.

The opening in the base of the main chamber is preferably arranged in register with the apex of the conical seating defined by the upper wall of the ink outlet chamber and the float element may be formed with an upwardly extending spike or rod which projects into the main chamber and acts as a guide for the float element.

The ink outlet chamber preferably has an outlet port at its base and, spaced upwardly from the base, an upwardly facing frusto-conical seating for the float element when in its lowermost position. The distance of travel of the float element between its lowermost and uppermost positions is preferably substantially less than the length of the spike or rod extending upwardly from the float element.

In an alternative design, the float element is of spherical form and is arranged to have sealing engagement with a complementary seating the centre of which communicates with the outlet of the main chamber.

In a further alternative design, the float element is in the form of a door or gate which is hingedly mounted at its one edge and is mounted in the outlet from the main chamber in such manner that, when the ink in the ink outlet chamber reaches a predetermined level, the door or gate will move upwardly about its hinge to close the outlet from the main chamber.

The main chamber may contain an internal wall or fin which extends downwardly from the top of the cartridge for the major portion of the height of the main chamber (i. e. it terminates short of the base of the main chamber), and extends longitudinally of the main chamber for the major portion of the length of the main chamber, terminating short of both ends of the main chamber. The internal wall or fin prevents"sloshing"of the ink within the main chamber.

In an alternative arrangement to prevent"sloshing"of the ink within the main chamber, a buoyant film is placed in the main chamber so that it floats on top of the ink in the main chamber.

Brief Description of the Drawings Figure 1 is a first sectional view of an ink cartridge, Figure 2 is a second sectional view of the ink cartridge, taken at right angles to Figure 1, Figure 3 is a sectional view of a first alternative form of ink cartridge, Figure 4 is a sectional view of a second alternative form of ink cartridge, and Figure 5 is a sectional view of a third alternative form of ink cartridge.

Description of the Preferred Embodiment The ink cartridge shown in Figures 1 and 2 of the drawings comprises a plastic fabrication of general rectangular form in plan view and has a main chamber 10 defined by a top 11, a front wall 12, a rear wall 13, two side walls 14 and 15 and a base 16. A centrally disposed fin 17 depends downwardly from the top 11 and extends for the majority of the length of the main chamber 10, terminating short of both the front wall 12 and the rear wall 13. The fin 17, which acts to restrain"swirling"or"sloshing"of the ink within the main chamber 10, also terminates short of the base 16.

As shown in Figures 1 and 2, the base 16 is inclined downwardly from each side and each end towards an opening 18 which communicates with an ink outlet chamber 19 contained within a protrusion 20 depending downwardly from the front portion of the base 16 of the main chamber 10. The protrusion 20 has a flat lower surface 21 and the rear wall 13 of the main chamber 10 extends downwardly beyond its junction with the base 16 such that its lower edge 22 is in the same plane as that of the flat lower surface 21 of the protrusion 20.

The ink outlet chamber 19 has a delivery port which opens onto the lower surface 21 centrally thereof and, as supplied to a user, the delivery port is closed by a self-adhesive seal 23. The ink outlet chamber 19 includes an upwardly facing frusto-conical seating 24, a cylindrical wall 25 and a downwardly facing conical seating 26. The apex of the downwardly facing seating 26 is formed as an opening which communicates with the opening 18 in the base 16 of the main chamber 10 so that a passage is afforded for the flow of ink from the main chamber 10 into the ink outlet chamber 19.

A float element 27 formed of a low density plastic material, for example, low density polyethylene or polystyrene having a Specific Gravity significantly less than 0.2, is contained within the ink outlet chamber 19. The float element 27 has an upwardly facing conical surface 28 complementary to the downwardly facing seating 26, a downwardly facing conical surface 29 complementary to the upwardly facing seating 24 and a centrally positioned upwardly extending spike 30 which extends upwardly through the opening 18 and projects into the main chamber 10. The cross-sectional dimensions of the spike 30 are such that there is an annular gap between the spike 30 and the circumference of the opening 18.

The float element 27 is movable between upper and lower limiting positions, in contact with either the downwardly facing seating 26 or the upwardly facing seating 24. When the float element 27 is in its lower limiting position, ink can enter the ink outlet chamber 19 through the opening 18 and passes through the annular gap around the spike 30. As the ink enters the ink outlet chamber 19 and the level of ink in said chamber 19 increases, the float element 27 will be displaced upwardly until it reaches its upper limiting position, in which it has sealing engagement with the downwardly facing seating 26 to prevent the further entry of ink into the ink outlet chamber 19 through the opening 18.

In use of the cartridge, ink will be withdrawn through the outlet port of the ink outlet chamber 19 and, as the level of ink in the ink outlet chamber 19 falls, the float element 27 will move downwardly clear of the downwardly facing seating 26 to allow the flow of further ink into the ink outlet chamber 19. Controlled flow of ink from the main chamber 10 into the ink outlet chamber 19 is thus obtained.

The length of the upwardly extending spike 30 is greater than the distance of travel of the float element 27. The spike 30 thus acts as a guide element for the float element 27, as well as affording a restriction in the opening 18, thereby reducing the rate of flow of the ink through the opening 18.

One of the walls of the main chamber 10 is provided with a salable opening (not shown) through which air can be withdrawn from the chamber 10 and through which ink is introduced into the main chamber. The top 11 of the main chamber 10 is formed with a breather hole (also not shown). In the form in which the cartridge is supplied to the customer, the breather hole is sealed with a piece of tape. The tape may be applied before the cartridge is evacuated and filled and the cartridge user is obliged to remove the tape before fitting the cartridge in a printer.

In the alternative design shown in Figure 3, the float element 27 of the embodiment shown in Figures 1 and 2 is replaced by a spherical float element 30 which is formed of a low density plastic material and is arranged for sealing engagement with a complementary, downwardly facing seating 31 at the top of the ink outlet chamber 19.

The downwardly depending fin 17 of the embodiment shown in Figures 1 and 2 is replaced by a buoyant film 32 which sits on top of the ink in the main chamber 10 to prevent or reduce"sloshing"of the ink.

The mode of operation of the cartridge of Figure 3 is as described above in relation to Figures 1 and 2.

The further design shown in Figure 4 includes a door or gate 33 which is formed of a low density plastic material and is hinged at one side with the arrangement such that, when the ink in the ink outlet chamber 19 reaches a predetermined level, the door or gate 33 will be urged upwardly so that the free edge of the door or gate 33 engages a stop 34 and closes the opening 18 from the main chamber 10 into the ink outlet chamber 19.

The mode of use of the cartridge of Figure 4 is as above and it may be provided with either a fin 17 or a buoyant film 32 to prevent or reduce"sloshing"of the ink within the main chamber 10.

Turning next to Figure 5, this shows a modification of the arrangement shown in Figures 1 and 2 in which, instead of the ink being contained directly in the main chamber 10, the ink is contained within a flexible, metallised foil bag 35 the mouth of which is sealed to the entrance to the float valve chamber. The bag 35 is initially completely filled with ink and thus totally air-free. Thus, as ink is drawn into the printer, under the control of the float valve, atmospheric pressure will cause the bag 35 to collapse. Such action will effectively cause the ink to flow up-hill from the area indicated at A in Figure 5.

The bag 35 is filled with ink at atmospheric pressure, squeezed to make the ink rise to the throat of the bag 35 and then part (or all) of the float valve system is jammed into the throat of the bag 35 to make an air-tight and ink-tight seal. With this arrangement, a vacuum filling system is not required, and no fin 17 or buoyant film 32 is required to prevent"sloshing"of the ink.

It will be appreciated that the float valve systems shown in Figures 3 and 4 can also be used in conjunction with the bag system of Figure 5.

Claims

Claims : -

1. An ink cartridge which includes a main chamber within which the ink is stored, an ink outlet chamber and a float valve controlling the passage of ink from the main chamber to the ink outlet chamber.

2. An ink cartridge as claimed in Claim 1, in which the ink outlet chamber is contained within an extension projecting downwardly from the base of the main chamber.

3. An ink cartridge as claimed in Claim 2, in which the float valve is arranged to control the flow of ink through an opening in the base of the main chamber into the ink outlet chamber.

4. An ink cartridge as claimed in Claim 3, in which the base of the main chamber is inclined, with the opening in the base at the lowermost part of the base, so that the ink drains downwardly to said opening, which communicates with the ink outlet chamber.

5. An ink cartridge as claimed in any one of the preceding claims, in which the float valve comprises a float element formed of a low density plastics material, for example, low density polyethylene having a specific gravity less than 0.2

6. An ink cartridge as claimed in any one of the preceding claims, in which the float element has an upper surface of conical form which, when the float valve is in its uppermost position, is arranged to have sealing engagement with a complementary conical seating defined by the upper wall of the ink outlet chamber.

7. An ink cartridge as claimed in Claim 6, in which the opening in the base of the main chamber is arranged in register with the apex of the conical seating defined by the upper wall of the ink outlet chamber.

8. An ink cartridge as claimed in Claim 7, in which the float element is formed with an upwardly extending spike or rod which projects into the main chamber and acts as a guide for the float element.

9. An ink cartridge as claimed in any one of Claims 6 to 8, in which the ink outlet chamber has an outlet port at its base and, spaced upwardly from the base, an upwardly facing frusto-conical seating for the float element when in its lowermost position.

10. An ink cartridge as claimed in any one of Claims 1 to 5, in which the float element is of spherical form and is arranged to have sealing engagement with a complementary seating the centre of which communicates with the outlet of the main chamber.

11. A ink cartridge as claimed in any one of Claims 1 to 5, in which the float element is in the form of a door or gate which is hingedly mounted at its one edge and is mounted in the outlet from the main chamber in such manner that, when the ink in the ink outlet chamber reaches a predetermined level, the door or gate will move upwardly about its hinge to close the outlet from the main chamber.

12. An ink cartridge as claimed in any one of the preceding claims, in which the ink is stored in a flexible bag contained within the main chamber.

13. An ink cartridge as claimed in Claim 12, in which the bag is a metallised foil bag.

14. An ink cartridge as claimed in any one of Claims 1 to 11, in which the main chamber contains an internal wall or fin which extends downwardly from the top of the cartridge for the major portion of the height of the main chamber (i. e. it terminates short of the base of the main chamber), and extends longitudinally of the main chamber for the major portion of the length of the main chamber, terminating short of both ends of the main chamber.

15. An ink cartridge as claimed in any one of Claims 1 to 11, in which a buoyant film floats on top of the ink in the main chamber.

16. An ink cartridge substantially as hereinbefore described with reference to and as shown in the accompanying drawings.