WO2019013753A1

WO2019013753A1 - Printing fluid cartridge

Info

Publication number: WO2019013753A1
Application number: PCT/US2017/041378
Authority: WO
Inventors: Ben Smith; Aidan O REILLY; Garry Rooney; Mary DILLON; John Mulrennan; Paul KEALY
Original assignee: Hewlett-Packard Development Company, L.P.
Priority date: 2017-07-10
Filing date: 2017-07-10
Publication date: 2019-01-17

Abstract

A printing fluid cartridge is described. An example printing fluid cartridge includes a housing defining a cavity and an opening, a lid arranged to close the opening, and a medium disposed within the cavity to receive printing fluid when the printing fluid cartridge is filled. A polymer foam is then disposed within the cavity between the medium and the lid, wherein the polymer foam is arranged to absorb printing fluid that emanates from the medium.

Description

PRINTING FLUID CARTRIDGE

BACKGROUND

[0001] Printing fluid cartridges, or "pens", are used in many printers. Such printing fluid cartridges may be provided as "integrated printheads", wherein the printing fluid cartridges comprises both a printing fluid reservoir and a printhead for supplying print fluid to a medium. For example, the printhead may comprise an ink jet printhead. Printing fluid cartridges are often filled with printing fluid prior to supply to a user. It is generally undesirable for printing fluid contained in a printing fluid cartridge to leak out onto the user.

BRIEF DESCRIPTION OF THE DRAWINGS

[0002] Various features of the present disclosure will be apparent from the detailed description which follows, taken in conjunction with the accompanying drawings, which together illustrate features of the present disclosure, and wherein:

[0003] Figure 1A is a schematic diagram showing a perspective cutaway view of a printing fluid cartridge according to an example;

[0004] Figure 1 B is a schematic diagram showing a sectional view of the printing fluid cartridge shown in Figure 1 A;

[0005] Figures 2 is a schematic diagram showing a sectional view of a printing fluid cartridge according to another example;

[0006] Figure 3 is a flow diagram showing a method of manufacturing a print cartridge according to an example; [0007] Figure 4 is a schematic diagram showing an ink-jet printer system according to an example; and

[0008] Figures 5A to 5E are schematic diagrams illustrating stages in a method of manufacturing a print cartridge according to an example.

DETAILED DESCRIPTION

[0009] In the following description, for the purpose of explanation, numerous specific details of certain examples are set forth. Reference in the specification to "an example" or similar language means that a particular feature, structure, or characteristic described in connection with the example is included in at least that one example, but not necessarily in other examples.

[0010] Printing fluid cartridges (also referred to as 'print' cartridges for brevity herein), such as those for use with inkjet printers, may be supplied pre- filled with a printing fluid such as ink. That is, the cartridge may be filled with ink before sale, and a user may replace an empty cartridge with another pre-filled cartridge. A user may handle such pre-filled cartridges when replacing spent cartridges in a printer. It may be undesirable for printing fluid to leak from the print cartridge onto a user when being handled by the user.

[0011] The print cartridges described herein may be provided with or without printing fluid. The term "printing fluid" includes all fluids that may be deposited on a print medium from a cartridge, including fluids such as ink, toner, varnish, gloss, fusing agent, detailing agent etc. For ease of explanation, an example of ink is used in descriptions herein; however, this should not be seen as limiting. An ink may be an oil or water based ink with one or more colorants, e.g. inks may be supplied as cyan, magenta, yellow and/or black inks. In some examples, the print cartridges described herein may be used in print systems configured to provide an image on the surface of a medium (also referred to as "2D printing"). In other examples, the print cartridges described herein may be used in additive manufacturing systems (also referred to as "3D printing").

[0012] The print cartridges described herein comprise a hydrophobic polymer foam. The term hydrophobic polymer generally refers to polymers to which water is not attracted. Such hydrophobic foams may include hydrophobic polyurethane, including hydrophobic polyether-based polyurethane. In some examples, the polyurethane may be a low density foam. In some examples, the polyurethane is a reticulated (open cell) foam. In some examples, such as when the polyurethane is a reticulate foam, the polyurethane may be a felted foam. Where the foam is a reticulated foam, included when it is a felted foam, the foam may have a fine porosity. Such foams may have from than 60 to 1 10 PPI (pores per inch), or 80 to 100 PPI, for example. In an example, the hydrophobic polymer foam comprises a low density, felted polyether-based polyurethane reticulated foam. The hydrophobic foam may be loaded with ink. In examples where the ink is a water-based ink, the hydrophobic foam may be loaded with ink by injecting the foam with the ink under reduced pressure. In such examples, the hydrophobic foam may efficiently deliver the water-based ink to a printhead, due to the low attraction between the hydrophobic foam and the water-based ink.

[0013] During transport, print cartridges may be exposed to a wide range of temperatures. For example, print cartridges may be exposed to temperatures ranging from -40 °C to 60 °C. When a print cartridge filled with a water-based ink is exposed to low temperatures (such as below 0 °C), for example, the water- based ink may at least partially solidify, i.e. freeze. The volume of a frozen ink may differ from the volume of a liquid ink. For example, a frozen water-based ink may have a greater volume and thus extend further through an ink-loaded foam than a liquid water-based ink, as water expands upon freezing.

[0014] During transport, the print cartridges may experience a "temperature cycle". A temperature cycle may refer to exposing a cartridge to a low temperature followed by a high temperature, and vice versa. If the low temperature freezes the liquid in the cartridge and the high temperature thaws the liquid, these temperature cycles may also be referred to as "freeze-thaw" cycles.

[0015] A cartridge may undergo several temperature cycles. For example, a print cartridge containing a water-based ink may undergo several freeze-thaw cycles. After each freeze, the water-based ink will expand and extend further towards the surface of the hydrophobic ink. After experiencing a plurality of freeze-thaw cycles, the water-based ink may have extended to the surface of the hydrophobic foam. Upon melting, the water-based ink at the surface will emanate from the hydrophobic foam because there is low attraction therebetween. This emanated or "free" ink may move around the ink reservoir of the print cartridge unhindered, without being re-absorbed by the hydrophobic foam.

[0016] Print cartridges according to present examples also contain a hydrophilic polymer foam. The term hydrophilic polymer generally refer to polymers to which water is attracted. In some examples, the hydrophilic polymer may comprise hydrophilic polyurethane. In some examples, the hydrophilic polymer foam may be a spray polyurethane foam, such as a low density spray polyurethane foam. In some examples, the hydrophilic polymer foam may be a foam obtained by combining an isocyanate component (or "A" component) and a polyol resin (or "B" component) which, when combined, expand to more than the liquid volume to provide a solid hydrophilic polymer open-cell foam. The isocyanate component may comprise a plurality of isocyanates. The isocyanate component may comprise methylene diphenyl diisocyanate (MDI), for example. The polyol resin component may comprise a plurality of polyols. For the avoidance of doubt, according to the present disclosure, water and water-based inks have a greater attraction to hydrophilic foams than hydrophobic foams.

[0017] In certain examples described herein, there may be a strong attraction between the free ink in an ink reservoir and the hydrophilic foam, particularly if the free ink is a water-based ink. Accordingly, the hydrophobic foam may absorb any free ink present in the ink reservoir. By disposing the foam between the ink-carrying hydrophobic foam and the lid of the print cartridge, the foam may prevent free ink leaking through the lid of the print cartridge, which otherwise would leak onto a user when the cartridge is handled by the user.

[0018] Figure 1A shows a cutaway perspective view of a printing fluid ('print') cartridge 100 according to an example. Figure 1 B shows a sectional view of the same print cartridge 100. In the cutaway perspective a side wall of the print cartridge 100 is removed such that an interior of the cartridge may be viewed.

[0019] The print cartridge 100 comprises a housing 1 10. The housing defines a cavity 1 12 and an opening. The opening may be located at the top of the cavity 1 12. The cavity 1 12 may be defined by side walls of the print cartridge, i.e. as an interior to the housing 1 10. The cavity 1 12 may be referred to as an ink reservoir, i.e. as it is arranged to hold a printing fluid such as ink. It should be noted that Figure 1A shows a simplified print cartridge 100 to better explain the present examples, actual print cartridges may comprise additional features and/or may be of a more complex shape.

[0020] The cartridge 100 also comprises a lid 120. The lid 120 is arranged to block the opening of the housing 1 10. In Figure 1A, the lid is arranged as a substantially planar surface that may be overlaid on top of the housing 1 10. The housing 1 10 may have a surface facing the cavity 1 12, which may be referred to as the internal surface of the housing 1 10. This surface may include the tops of the side walls and the opening. Similarly, the lid 120 may have a surface facing the cavity 1 12, which may be referred to as the internal surface of the lid 120. The internal surface of the lid 120 refers to the portion of the lid surface which covers the cavity 1 12; there may be other portions of the lid surface that do not cover the cavity 1 12, e.g. that abut the top surfaces of the side walls and/or that overhang the housing 1 10. Specifically, if the lid 120 extends beyond the opening, the portions of the surface of the lid which do not contact the cavity 1 12 are not considered part of the internal surface of the lid 120.

[0021] The print cartridge may comprise ink (not pictured). When ink leaves the print cartridge 100 in use, for example when passing through a printhead to be deposited on a medium, there may be a corresponding pressure drop in the cavity 1 12. If the pressure in the cavity 1 12 is substantially lower than the pressure outside the print cartridge 100, the flow of ink from the cartridge may be reduced. This may be referred to as "pen starvation". Accordingly, in some examples, lid 120 may comprise one or more openings (not pictured) such that the cavity 1 12 is in fluid communication with the area outside the print cartridge. That is, in some examples, air may pass through the lid 120 from outside the print cartridge to the cavity 1 12, and vice versa, such that the pressure in cavity 120 is substantially uniform throughout use.

[0022] In the example of Figure 1A, the cartridge 100 comprises a hydrophobic polymer foam 130. The hydrophobic polymer foam 130 is disposed within the cavity 1 12. Said hydrophobic polymer foam 130 may be used to carry an ink in the print cartridge. The hydrophobic polymer foam 130 may comprise any of the hydrophobic polymer materials described hereinabove. The hydrophobic polymer foam 130 is a not a liquid foam. That is, the foam is not formed of liquid material comprising pockets of gas. For example, the foam 130 may be a solid foam - a foam formed of solid material comprising pockets of gas (e.g. air). Said pockets in the solid foam may be discrete (i.e. the gas within each pocket is isolated from the area outside of said pocket) or may be in fluid communication with each other (i.e. allowing movement of the gas between the pockets and/or the area outside of the foam).

[0023] The hydrophobic foam 130 may have any shape. It may be injected or otherwise inserted into the cavity 1 12. For example, the foam 130 may have a substantially cuboid or spherical shape, for example, or the foam 130 may be substantially amorphous. The foam 130 may have one or more surfaces. For example, the foam 130 may have a top surface, facing the lid 120 of the cartridge 100. In some examples, the housing 1 10 may have a base portion 1 14 as shown in Figure 1 B. Thus, the foam 130 may have a bottom surface, facing the base portion 1 14 of the housing 1 10 of the cartridge 100. In some examples, the hydrophobic foam 130 may abut the base 1 14, i.e. the bottom surface of the foam 130 may abut the base 1 14 as shown in Figure 1 C.

[0024] In some examples, the housing 1 10 may have a sidewall 1 16 as shown in Figure 1 B. The sidewall 1 16 may or may not be arranged substantially perpendicular to the lid 120. The foam 130 may have a side surface, facing a sidewall 1 16 of the housing 1 10. In some examples, the hydrophobic foam 130 may abut the sidewall 1 16. In some examples, the hydrophobic foam 130 may abut substantially all the portions of the sidewall 1 16 facing the internal cavity 1 12 which are arranged in a single plane coplanar with the lid 120.

[0025] In the example of Figures 1 A and 1 B, the print cartridge also comprises a hydrophilic polymer foam 140. Said hydrophilic foam 140 may comprise any of the hydrophilic polymer materials described hereinabove. The hydrophilic polymer foam 140 is a not a liquid foam. That is, the foam is not formed of liquid material comprising pockets of gas. For example, the foam 140 may be a solid foam. [0026] The hydrophilic foam 140 may have any shape. For example, the foam 140 may have a substantially cuboid or spherical shape, for example, or the foam 140 may be substantially amorphous. The hydrophilic foam 140 may be injected or otherwise deposited within the cavity 1 12. The foam 140 may have one or more surfaces. For example, the foam 140 may have a top surface, facing the lid 120 of the cartridge 100. In some examples, the foam 140 may abut the lid 120. The foam 140 may have a bottom surface, facing the base portion of the housing 1 10 of the cartridge 100. The foam 140 may have a side surface, facing a sidewall of the housing 1 10, the sidewall being arranged substantially perpendicular to the lid 140. In some examples, the hydrophilic foam 140 may abut the sidewall 1 16. In some examples, the hydrophilic foam 140 may abut substantially all the portions of the sidewall 1 16 facing the internal cavity 1 12 which are arranged in a single plane coplanar with the lid 120.

[0027] The hydrophilic polymer foam 140 is disposed within the cavity 1 12, arranged between the hydrophobic polymer foam 130 and the lid 120.

[0028] In some examples, the hydrophobic foam and the hydrophilic foam are not separated by a wall, membrane or the like. In some examples, a solid material is not disposed between the hydrophobic foam 130 and the hydrophilic foam 140. Similarly, in some examples, the hydrophilic foam 140 and the lid 120 are not separated by a wall, membrane or the like. In some examples, a solid material is not disposed between the hydrophilic foam 140 and the lid 120.

[0029] In some examples, the hydrophilic foam 140 may abut the hydrophobic foam 130. Accordingly, a bottom surface of the hydrophilic foam 140 may abut a top surface of the hydrophobic foam 130. This may be the case if the hydrophilic foam 140 is injected onto the top surface of the hydrophobic foam 130.

[0030] In some examples, the hydrophilic foam may abut the hydrophobic foam 130 and the lid 120. Accordingly, a bottom surface of the hydrophilic foam 140 may abut a top surface of the hydrophobic foam 140, and a top surface of the hydrophilic foam 140 may abut an internal surface of the lid 120.

[0031] Figure 2 shows a cross-sectional view of a print cartridge 200 according to another example. For brevity, features in Figure 2 and the functions thereof that are the same as those features already described with reference to Figures 1 A and 1 B are given similar reference numerals to those in Figures 1A and 1 B but increased by 100.

[0032] Print cartridge 200 comprises hydrophilic polymer foam 240 arranged as a layer. The hydrophilic foam 240 may abut substantially all of the portions of the sidewall 216 facing the internal cavity 1 12 which are arranged in a single plane coplanar with the lid 120. The foam 240 may substantially extend across the area of a plane coplanar with the lid, defined by the internal surface of the housing. As such, the hydrophilic foam 240 may block the opening of the housing 210.

[0033] Hydrophilic layer 240 may also abut the lid 220. The foam 240 may abut substantially all of the internal surface of the lid 220. In a further example, the hydrophilic layer 240 may substantially extend across the area of a plane coplanar with the lid, defined by the internal surface of the housing, abut substantially all of the portions of the sidewall 216 facing the internal cavity 1 12 which are arranged in a single plane coplanar with the lid 120, and abut substantially all of the internal surface of the lid 220.

[0034] The foams used in the present print cartridge may be closed cell foams or open cell foams. A closed cell foam comprises discrete pockets of gas, each pocket being completely surrounded by a non-liquid (such as solid) material. That is, the cells in a closed cell foam are not in fluid communication. An open cell foam (also referred to as a reticulated foam) comprises pockets of gas which are not completely surrounded by non-liquid (such as solid) material, and thus are connected to each other. That is, the cells in an open cell foam are in fluid connection. Accordingly, a fluid may pass substantially all the way through an open cell foam from one surface to an opposite surface, whereas a closed cell foam will present a physical barrier to the movement of a fluid.

[0035] The hydrophilic foam 240 may comprise open cell foam. The open cell hydrophilic polymer foam 240 may allow fluid to flow between the cavity 212 and the lid 220. In an example, the hydrophilic foam 240 may comprise an open cell foam, and the lid 220 may comprise one or more openings. In this example, the cavity 212 is in fluid communication with the area outside the print cartridge. That is, air may pass through the lid 220 and the hydrophilic foam 240 to the cavity 212, and vice versa. Thus, this example may provide a cartridge which provides a barrier to ink leakage on a user without pen starvation.

[0036] In another example, the hydrophilic foam 240 may adhere to the housing 210, the lid 220, or the sidewall 210 and the lid 220. Any method of addition may be used to adhere the hydrophilic foam 240 to the housing 210 and/or lid 220. For example, an adhesive or adhesive tape may be provided between the hydrophilic foam 240 and the housing 210 and/or lid 220. In another example, the hydrophilic polymer foam precursor may crosslink (e.g. cure) in the cavity 212 when abutting the housing 210 and/or lid 220, to provide the hydrophilic polymer foam 240 adhering to the housing 210 and/or lid 220.

[0037] Figure 3 is a flow diagram showing a method 300 of manufacturing a printing fluid ('print') cartridge according to an example. In this example, the method 300 comprises loading a hydrophobic polymer with printing fluid 310. The printing fluid may be an ink, such as a water-based ink. The hydrophobic polymer foam may be disposed in a print cartridge as described above, e.g. the hydrophobic polymer foam may be disposed in a cavity of a print cartridge having an opening. The cavity may be referred to as an ink reservoir.

[0038] The next block 320 composes applying a hydrophilic polymer foam precursor on top of the hydrophobic polymer foam 320. In an example, the precursor is a liquid. Said liquid may be supplied with a needle, for example. In this case, applying the hydrophilic polymer foam precursor may comprise using a foam supply needle to inject the hydrophilic polymer foam precursor into a space above the hydrophobic polymer foam. The precursor may comprise a plurality of components. For example, if the liquid is a hydrophilic spray polyurethane foam precursor, the precursor may comprise isocyanate (or "A" component) and polyol resin (or "B" component).

[0039] Block 330 comprise closing the cavity with a lid. The lid may close the cavity after application of the hydrophilic polymer foam precursor. Alternatively, the lid may close the cavity prior to application of the hydrophilic polymer foam precursor, and hydrophilic polymer foam precursor may be supplied to the cavity through an opening in the lid. [0040] The hydrophilic polymer foam precursor may then crosslink (or "cure") to provide a hydrophilic polymer foam. Components of a polymer precursor composition may crosslink to provide a polymer composition. In some examples, an external stimulus may be applied to the polymer precursor composition to provide a polymer composition. For example, the precursor composition may be subjected to UV radiation, or heat treatment. In other examples, components of a polymer precursor composition may crosslink without the application of an external stimulus. That is, given time, the components of a polymer precursor composition may crosslink to provide a polymer without application of an external stimulus.

[0041] In an example, the hydrophilic polymer foam precursor may crosslink without the application of an external stimulus. The hydrophilic polymer foam precursor may cross link within 5, 10, 15, or 20 minutes, for example, without application of an external stimulus. In examples wherein the precursor is a hydrophilic spray polyurethane foam precursor and comprises polyol resin and isocyanate, the precursor may crosslink without the application of an external stimulus. Not applying an external stimulus to the hydrophilic polymer foam precursor may provide a simple and quick method of manufacturing a hydrophilic polymer foam.

[0042] By crosslinking the hydrophilic polymer foam precursor in contact with a surface of the lid of the print cartridge, the hydrophilic polymer foam precursor may adhere to the lid. Said adhesion may obviate the need for the lid to undergo any separate step in order to attach the lid to the housing of the print cartridge. For example, crosslinking the hydrophilic polymer foam precursor in contact with a surface of the lid of the print cartridge may obviate the need to weld the lid to the housing of the print cartridge.

[0043] In certain examples, the hydrophobic polymer foam may be applied to an internal cavity of the printing fluid cartridge before loading the hydrophobic polymer foam. In one case, the hydrophobic polymer foam may also be injected and cured. Similarly, loading the hydrophobic polymerfoam with printing fluid may comprise inserting an ink fill needle into the hydrophobic polymer foam and injecting a fixed amount of printing fluid through the ink fill needle. [0044] Figure 4 shows an example of a printer system 400 where print cartridges described herein may be used. The printer system 400 may comprise an ink jet printer system. In Figure 4, the printer system 400 comprises a plurality of print cartridges 41 OA to D. Although four print cartridges are shown in Figure 4, other numbers of print cartridges may be installable in practice. The print cartridges may form part of a static print bar, e.g. in a page wide array printer system, or may be mounted in a moveable carriage that scans over at least a width of a print medium. In the example of Figure 4, each print cartridge comprises an integrated printhead 420, an ink chamber 430 and an upper cover 440. The ink chamber 430 and the upper cover 440 may be considered similar to the cavity 1 12, 212 and lid 120, 210 shown in Figures 1 A, 1 B and 2. The integrated printhead 420 may comprise an ink jet mechanism, such as a piezo electric member and nozzle for ejecting drops of ink supplied from the ink chamber 430. In some examples, the printer system 400 is a 2D printing system. In these examples, the integrated printhead 420 may be a 2D printhead. In other examples, the printing system 400 may be an additive manufacturing system ("3D printing system"). In these examples, the integrated printhead 420 maybe a 3D printhead.

[0045] In Figure 4, the ink chamber 430 comprises an ink holding media 450. This may comprise the aforementioned hydrophobic foam 130. The ink holding media 450 fills the ink chamber 430 up to a height below that of the ink chamber, i.e. such that there is a vertical gap between the top of the ink holding media 450 and the top of the print cartridge 410. The ink holding media contains ink for ejection by the integrated printhead 420.

[0046] In Figure 4, the ink chamber 430 further comprises a cured polymer foam 470 disposed on top of the ink holding media 450. This may comprise the aforementioned hydrophilic foam 140. The cured polymer foam 470 is arranged to absorb ink that migrates from the ink holding media 450 to prevent escape of ink beyond the upper cover 440. In the example of Figure 4, the upper cover 440 is adhered to the cured polymer foam. This may be in addition to a mechanical connection between the upper cover 440 and the body of the print cartridge 410. The adhesion fastens the upper cover 440 into place for the print cartridge 410. [0047] Figures 5A to 5E illustrate stages in a process to manufacture a print cartridge as described in Figures 1A, 1 B, 2 or 4. Figure 5A shows an empty print cartridge with an open, i.e. unfastened, lid. Figure 5B shows the print cartridge having been filled with an ink holding media such as a hydrophobic foam. At the stage of Figure 5B a printing fluid may be loaded into the ink holding media, e.g. under pressure. Figure 5C then shows the injection of a curable polymer foam. This may be a hydrophilic foam. In Figure 5D it is seen how the curable polymer foam fills a space at the top of the print cartridge above the ink holding media. For example, the foam may be an expanding foam. In Figure 5D, the lid is affixed to the top of the print cartridge. A lower surface of the lid makes contact with the curable polymer foam. Figure 5E then shows the print cartridge following curing of the curable polymer foam. The curing of the polymer foam adheres the lid. The print cartridge is thus ready for supply.

[0048] Certain examples described herein prevent leakage of printing fluid during transit, e.g. following multiple "freeze-thaw" cycles. They allow excess printing fluid under a printing fluid cartridge to be absorbed to prevent spillage. Certain solutions prevent ink seepage through a lid, while still allowing venting, e.g. allowing gaseous exchange but controlling fluid migration. Certain examples may also have the surprise added benefit of avoiding a costly ultrasonic welding stage to attach a lid or cover to the printing fluid cartridge.

[0049] The preceding description has been presented to illustrate and describe examples of the principles described. This description is not intended to be exhaustive or to limit these principles to any precise form disclosed. Many modifications and variations are possible in light of the above teaching. It is to be understood that any feature described in relation to any one example may be used alone, or in combination with other features described, and may also be used in combination with any features of any other of the examples, or any combination of any other of the examples.

Claims

CLAIMS What is claimed is:

1 . A printing fluid cartridge comprising:

a housing defining a cavity and an opening;

a lid arranged to close the opening;

a hydrophobic polymer foam disposed within the cavity to receive printing fluid when the printing fluid cartridge is filled; and

a hydrophilic polymer foam disposed within the cavity between the hydrophobic polymer foam and the lid,

wherein the hydrophilic polymer foam is arranged to absorb printing fluid that emanates from the hydrophobic polymer foam.

2. The printing fluid cartridge of claim 1 , wherein the hydrophilic polymer foam abuts the hydrophobic polymer foam.

3. The printing fluid cartridge of claim 1 , wherein the hydrophilic polymer foam abuts the lid.

4. The printing fluid cartridge of claim 1 , wherein the height of the hydrophobic polymer foam is less than the height of the cavity and the hydrophilic foam abuts both the hydrophobic foam and the lid.

5. The printing fluid cartridge of claim 1 , wherein the hydrophilic foam adheres to the lid.

6. The printing fluid cartridge of claim 1 , wherein the lid has an internal surface facing the cavity, and the hydrophilic foam is distributed across the internal surface.

7. The printing fluid cartridge of claim 1 , wherein the lid is fixed to the housing by at least the hydrophilic polymer foam.

8. The printing fluid cartridge of claim 1 , wherein the printing fluid cartridge comprises an integrated printhead.

9. The printing fluid cartridge of claim 1 , wherein the hydrophilic foam comprises an expanding hydrophilic urethane foam compound.

10. A method of manufacturing a printing fluid cartridge for use in a printer, the method comprising:

loading a hydrophobic polymer foam disposed within the printing fluid cartridge with printing fluid;

applying a hydrophilic polymer foam precursor on top of the hydrophobic polymer foam; and

applying a lid to close the printing fluid cartridge,

wherein the hydrophilic polymer foam precursor is crosslinked to adhere the lid to the printing fluid cartridge.

1 1 . The method of claim 10, comprising, before loading the hydrophobic polymer foam:

applying the hydrophobic polymer foam to an internal cavity of the printing fluid cartridge.

12. The method of claim 10, wherein the printing fluid comprises ink.

13. The method of claim 10, wherein loading the hydrophobic polymer foam with printing fluid comprises inserting an ink fill needle into the hydrophobic polymer foam and injecting a fixed amount of printing fluid through the ink fill needle.

14. The method of claim 10, wherein applying the hydrophilic polymer foam precursor comprises using a foam supply needle to inject the hydrophilic polymer foam precursor into a space above the hydrophobic polymer foam. An ink jet printer system comprising:

a plurality of print cartridges,

each print cartridge comprising:

an integrated printhead;

an ink chamber comprising:

ink holding media, the ink holding media filling the ink chamber up to a height below that of the ink chamber, the ink holding media containing ink for ejection by the integrated printhead, and

a cured polymer foam disposed on top of the ink holding media; and

an upper cover for at least the ink chamber, the upper cover being adhered to the cured polymer foam,

wherein the cured polymer foam is arranged to absorb ink that migrates from the ink holding media to prevent escape of ink beyond the upper cover.