The present disclosure relates generally to fluid cartridges, and more particularly, to a fluid cartridge for a fluid supply system.
Inkjet printers often use replaceable fluid cartridges to supply ink and/or other fluids to a printing device to form an image on print media. Some fluid cartridges include two or more internal chambers configured to hold the ink, where the chambers are often separated by a wall having an air/ink exchange port formed therein. The air/ink exchange port provides air and/or ink communication between the chambers. The ink is selectively taken from one or more of the chambers and delivered to and ejected through nozzles of a printhead and then onto the print media. In some instances, however, fluid may continue to flow through the printhead even when the printhead is not actuated by the printer.
To prevent the free flow of ink during non-use of the printhead, a negative or back pressure is formed in the ink within the cartridge that overcomes the pressure at the printhead when the printhead is not in use. Thus, a vacuum is formed in the free ink chamber of the cartridge and holds the ink therein. The back pressure within the free ink chamber of the cartridge is generally maintained by capillary force and the flow of air and/or ink back and forth through the air/ink exchange port. Difficulties may arise, however, in maintaining the back pressure in the cartridge when additional, unintended air enters the air/ink exchange port from various leak regions that may form during construction of the fluid cartridge.
Further difficulties may arise from a lack of desirable back pressure. For example, if one cartridge fails to provide sufficient back pressure, the ink may drool out the nozzles onto the orifice plate, and then may be drawn up by back pressure of another color cartridge. This may result in undesirable color mixing.
Features and advantages of embodiment(s) of the present disclosure will become apparent by reference to the following detailed description and the drawings, in which like reference numerals correspond to similar, though not necessarily identical components. Reference numerals having a previously described function may not necessarily be described in connection with other drawings in which they appear.
Embodiment(s) of the fluid cartridge for the fluid supply system as disclosed herein advantageously constrict or otherwise restrict air flow to the air/ink exchange port from various undesired air flow paths that may form in the fluid cartridge. This air flow constriction substantially maintains the back pressure level in the cartridge, thereby reducing undesirable fluid flow through the nozzle(s). This novel air flow constriction is advantageously achieved by disposing air flow-restricting members adjacent to the air/ink exchange port. Inclusion of these members in the cartridge construction may also desirably broaden the margin of error for accurately sizing and disposing ink absorbing materials into the cartridge.
With reference now to the drawings,
A wall 22 is disposed within the housing 12, positioned substantially normal to the base 14 and extending outwardly from the base 14. The wall 22 also abuts opposing side walls 16, thereby forming first and second chambers 24, 26 in the housing 12. An interface or edge 28 is formed between the wall 22 and the base 14, and between the wall 22 and an adjacent opposing side wall 16.
An ink outlet or port 30 is formed in the base 14 located in the second chamber 26. The ink outlet 30 generally couples with a manifold of a printhead (not shown) including a plurality of ink nozzles. The ink outlet 30 also couples with the first and/or second chambers 24, 26, thereby providing fluid communication between the ink outlet 30 and the chambers 24, 26.
With reference now to
Referring now to
In an embodiment, and as better shown in
In general, when the printhead is activated, the printhead forces the ink to flow through the nozzles. When the printhead is deactivated, the printhead restricts ink flow therethrough. The nozzles are still open when the printhead is deactivated, but the pores are small enough that capillary force at the nozzles substantially prevents the cartridge from pulling air in through the nozzles. Since the nozzles are open, in some instances, they may undesirably leak ink if the cartridge 10 fails to provide desirable back pressure.
To substantially prevent the dripping and/or leaking of the ink through the nozzles, a back pressure is formed at the printhead when the printhead is deactivated, as mentioned briefly above. As used herein, the term “back pressure” refers to a partial vacuum formed within the ink in ink cartridge 10 to resist the flow of ink through the printhead. Thus, an increase in back pressure can be referred to as an increase in partial vacuum, and is measurable in terms of water column height. It is generally desirable to maintain a strong enough back pressure at the printhead to substantially prevent dripping of the ink. It should be understood, however, that the back pressure should be a suitable pressure such that the printhead overcomes the back pressure and ejects the ink when activated.
In an ideal system, the desirable back pressure level is continuously maintained in the ink cartridge 10 and at the printhead. However, changes in back pressure often may occur, for example, during changes in the ambient environment or with operation of the printhead. As the printhead ejects an ink drop, the depletion of ink from the free ink chamber 24 increases the back pressure of the chamber 24, thereby creating a larger vacuum.
In an embodiment, and with reference to
In another embodiment, and with reference now to
Although some example capillary forces are provided above for the first absorber 40a and the second absorber 40b, it is to be understood that any suitable capillary media having a suitable capillary force may be used. Generally, the second absorber 40b provides sufficient back pressure to prevent drooling at the nozzles. The first absorber 40a should have a higher capillary force than the second absorber 40b. Some suitable example capillary forces for the second absorber 40b range from about 2″ WC to about 5″ WC; and for the first absorber 40a range from about 3″ WC to about 6″ WC.
Without being bound to any theory, it is believed that it is desirable for the cartridge 10 to drain substantially the entire second absorber 40b first, then drain a small amount of the first absorber 40a in order to open a bubbler path for air to reach the FIC 24, and then consistently drain substantially the entire FIC 24 before draining any additional ink from the first absorber 40a. One reason it is believed this method may be desirable is the low-on-ink detection system (LOID) (not shown). A sensor configured to detect when the FIC 24 empties allows the printer to know that substantially the only ink left in the cartridge 10 is in the first absorber 40a. This generally allows the printer to more accurately predict when printing should stop in order to prevent dry firing of the nozzles and potential damage to the printhead. However, if the first absorber 40a were sometimes half drained when the FIC 24 empties because of, e.g., a delayed opening of the air path through the air/ink exchange port 32 to the FIC 24; and other times the first absorber 40a and a portion of the second absorber 40b were full of ink when the FIC 24 empties, e.g., due to an unintended air path to the bubbler/air/ink exchange port 32, the LOID system may become less useful.
Since the back pressure level in the cartridge 10 may be influenced by changes in environment, operation, etc., it is generally beneficial to prevent any additional undesirable fluid, especially air, from entering the air/ink exchange port 32. As shown in
The other potential air path(s) 46 are substantially transverse air paths formed at the interface or edge 28, and travel transversely from the interface 28 to both transverse sides 48, 50 of the air/ink exchange port 32. The air path(s) 46 may be created when the wall 22 is disposed within the housing 12 but not formed integrally therewith, thereby leaving small gaps at the interface 28 that may leak into the port 32. For example, the air path(s) 46 may be formed by a wrinkle, gap or bevel in the absorber 40, 40a that allows air to flow along the corner between the absorber 40, 40a and the housing 12.
With reference again to
In alternate embodiment(s), the air path(s) 46 may also be constricted by disposing a transverse air flow-restricting member 60 abutting/adjacent one of the two opposed sides 54, 56 of the longitudinal air flow-restricting member 52.
It is to be understood that the longitudinal air flow-restricting member(s) 52 may be of any suitable size, shape and/or configuration, may be formed from any suitable material, and may be disposed in any suitable location sufficient to desirably constrict/restrict longitudinal air flow as described herein.
Referring still to
It is contemplated as being within the purview of the present disclosure that the longitudinal air flow-restricting member 52 be attached to the cartridge 10 by any suitable manner, be of any suitable thickness, and be of any suitable width.
In an embodiment, the member 52 is integrally molded with housing 12. The thickness of the member 52 may generally be less than about 2 mm, which thickness advantageously creates local compression of the adjacent absorber 40, 40a. The member 52 is generally as wide as the air/ink exchange port 32; however, it may, in some instances, be beneficial for the member 52 to be wider (as shown in phantom in
In general, the thickness of the member 52 is relatively small, but sufficiently thick enough to compress the capillaries of the absorber 40, 40a when the member 52 is disposed and installed in the cartridge 10. This results in reduced pore sizes/local compression of the capillaries of the absorber 40, 40a located adjacent to the member 52. Without being bound to any theory, it is believed that this reduced pore size may generate a relatively high capillary force, e.g., about 8″ WC, thereby keeping the capillary pores filled with ink, and substantially preventing air traveling from between the base 14 and the absorber 40, 40a from reaching the air/ink exchange port 32.
As with the longitudinal air flow-restricting member 52, it is to be understood that the transverse air flow-restricting member(s) 60 (if included) may be of any suitable size, shape and/or configuration, may be formed from any suitable material, and may be disposed in any suitable location sufficient to desirably constrict/restrict transverse air flow as described herein.
In an embodiment, one transverse air flow-restricting member 60 is disposed in the absorbing chamber 26 adjacent to the wall 22 and to the side 54 of the longitudinal air flow-restricting member 52. If desired, a second member 60 (substantially identical to, and the mirror image of the one member 60) may be disposed on the other side 56 of the longitudinal air flow-restricting member 52. In an embodiment, the member(s) 60 are substantially triangularly-shaped inserts (e.g., gussets), substantially rectangularly-shaped inserts, substantially quarter circle/pie wedge-shaped inserts, and combinations thereof. The member(s) 60 may be positioned substantially orthogonally with respect to the side 36 of the wall 22 facing the second chamber 26 and substantially parallel with respect to the air/ink exchange port 32, thereby restricting or otherwise constricting air flow via the transverse air flow path(s) 46 and into the port 32.
Referring now to
It is desirable that the edges formed at the base of the ribs 62 be relatively sharp and not substantially curved, as it is believed that bubbles have difficulty conforming to sharp corners. It is to be understood that the ribs 62 may be of any suitable size, however, in an embodiment, the ribs 62 may be from about 0.2 mm to about 0.6 mm wide; and from about 0.2 mm to about 0.6 mm high. In an embodiment, the ribs 62 are about 0.4 mm wide and about 0.4 mm high. The space between the ribs 62 may range from about 0.2 mm to about 0.6 mm. In an embodiment, the space between ribs is about 0.4 mm.
The ribs 62 also may function to substantially prevent air traveling through the air/ink exchange port 32 from breaking the fluid connection between the absorber 40, 40a and the free ink chamber 24. For example, when air is rapidly taken into the FIC 24, it can suddenly reduce the vacuum in the FIC 24 and disconnect the fluid in the FIC 24 from the absorber/HCM 40, 40a. When this happens, the ink in the FIC 24 is stranded because the absorber 40, 40a cannot pull it into the absorber 40, 40a. However, with the ribs 62, it is believed that capillaries are maintained that allow the absorber 40, 40a to pull ink in from the FIC 24. This ink pulled in from the FIC 24 gradually increases the vacuum in the FIC 24, which creates a pressure differential to pull more air into the FIC 24. As more air is pulled into the air/ink exchange port 32, any bubbles occluding the port 32 are substantially dislodged and float up into the FIC 24, thereby restoring proper function. Further, although a single rib 62 may function suitably in some instances, it is believed that additional ribs 62 may advantageously reduce the possibility that all the potential capillary paths along the edges between the threshold 52 and the ribs 62 are blocked by air bubbles.
In an embodiment, the fluid chamber may be formed by providing the housing 12 including the base 14, the free ink chamber 24, and the absorbing chamber 26. The wall 22, including the air/ink exchange port 32 defined in the bottom portion thereof, is disposed in the housing that extends outwardly from and substantially normal to the base 14, thereby separating the free ink chamber 24 and the absorbing chamber 26. The longitudinal air flow-restricting member 52 is disposed in the absorbing chamber 26, adjacent to the air/ink exchange port 32 and extending outwardly therefrom at a predetermined distance. The absorber 40, 40a may then be placed inside the absorbing chamber 26 and against the member 52 such that capillary edges of the absorber 40 are compressed, thereby restricting undesirable air flow therethrough from longitudinal air flow path 44.
If the transverse air flow-restricting member(s) 60 are utilized in an embodiment(s), they may be disposed in the absorbing chamber 26, respectively adjacent to the sides 54, 56 of the member 52, and adjacent to the air/ink exchange port 32. This may be accomplished by any suitable method, however, in an embodiment, the transverse air flow-restricting members 60 are molded into the housing 12, and insertion of the absorber 40, 40a causes members 60 to pierce the capillary or porous medium of the absorber 40, 40a substantially without distorting the capillaries. The member(s) 60 are thereby formed inside the chamber 26, adjacent to the air/ink exchange port 32, and substantially restrict undesirable air flow from the transverse air flow path(s) 46. If desired, the second absorber 40b (formed from, e.g., a low capillary media) may then be placed in contact with, and in fluid communication with the first absorber 40a (formed from, e.g. a high capillary media) before the cover 18 is secured to the housing 12.
Also disclosed herein is a method of restricting air flow to the air/ink exchange port 32 in the fluid cartridge 10. An embodiment of the method includes providing the fluid cartridge 10 including the housing 12, base 14, and the first and second chambers 24, 26, as described above. Wall 22 extends outwardly from and substantially normal to the base 14 and is configured to separate the housing 12, thereby forming the first and second chambers 24, 26. An air/ink exchange port 32 is defined in a bottom portion of the wall 22 and adjacent to the base 14. The method further includes restricting longitudinal air flow. The method may in some embodiment(s) also include restricting transverse air flow. In a further alternate embodiment, the method also may include promoting fluid flow between the first and second chambers 24, 26.
The present disclosure provides many advantages, some of which include the following. The air flow-restricting members 52, 60 may advantageously substantially constrict/restrict undesirable air flow from, e.g., air paths 44, 46. Without being bound to any theory, it is believed that restricting the air flow from the air paths 44, 46 by, e.g., operatively placing/forming members 52, 60 allows the back pressure in the cartridge 10 to be desirably regulated between the free ink chamber 24 and the absorber chamber 26. This may substantially prevent leaking through the nozzles. Members 52, 60 may also permit simpler construction of the absorbers 40, 40a, 40b. For example, in order to prevent additional undesirable air flow through the air/ink exchange port 32 from various air paths (non-limiting examples of which are defined herein), the absorbers 40, 40a, 40b may require very specific sizing and cutting, as well as very intricate installation procedures, in order to prevent these potential air paths from forming. Members 52, 60 may advantageously obviate this need for precision in fabrication and installation of absorbers 40, 40a, 40b.
While several embodiments have been described in detail, it will be apparent to those skilled in the art that the disclosed embodiments may be modified. Therefore, the foregoing description is to be considered exemplary rather than limiting.
Number | Name | Date | Kind |
---|---|---|---|
6206514 | Tajima et al. | Mar 2001 | B1 |
6293665 | Pew et al. | Sep 2001 | B1 |
6644796 | Olsen | Nov 2003 | B2 |
20020012033 | Iwanaga et al. | Jan 2002 | A1 |
20020071012 | Breemes | Jun 2002 | A1 |
20030038866 | Yu | Feb 2003 | A1 |
20050270341 | Yamamoto | Dec 2005 | A1 |
20050270347 | Yamamoto | Dec 2005 | A1 |
Number | Date | Country |
---|---|---|
0739741 | Jul 2003 | EP |
Number | Date | Country | |
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20080259141 A1 | Oct 2008 | US |