WO2021194509A1

WO2021194509A1 - Fluid ejection devices with expansion member

Info

Publication number: WO2021194509A1
Application number: PCT/US2020/025350
Authority: WO
Inventors: Steve A. O'hara
Original assignee: Hewlett-Packard Development Company, L.P.
Priority date: 2020-03-27
Filing date: 2020-03-27
Publication date: 2021-09-30

Abstract

Examples of a fluid ejection device with an expansion member are described. In some examples, an expansion member may be coupled to a fluid chamber of the fluid ejection device. In some examples, the expansion member may receive air from the fluid chamber in response to a positive pressure event in the fluid chamber.

Description

FLUID EJECTION DEVICES WITH EXPANSION MEMBER

BACKGROUND

[0001] A printing device may print on print media. For example, a fluid ejection device may deposit a printing fluid, such as ink, on the print media. In some examples, the fluid ejection device may include a fluidic die to deposit the printing fluid on the print media.

BRIEF DESCRIPTION OF THE DRAWINGS

[0002] Various examples will be described below by referring to the following figures.

[0003] Fig. 1 is a section view illustrating an example of a fluid ejection device for a printing device that includes an expansion member;

[0004] Fig 2. is an example of a printing device using an expansion member to prevent printing fluid drool;

[0005] Fig. 3 is a section view illustrating an example of a fluid ejection device with an expansion chamber integrated with the body;

[0006] Fig. 4 is an exploded perspective view illustrating the example of a fluid ejection device with an expansion chamber integrated with the body;

[0007] Fig. 5 is an exploded perspective view illustrating an example of a fluid ejection device with an expansion chamber integrated with the manifold of the fluid ejection device;

[0008] Fig. 6 is a section view illustrating the example of a fluid ejection device with an expansion chamber integrated with the manifold of the fluid ejection device; [0009] Fig. 7 is an exploded perspective view illustrating an example of a fluid ejection device with an expansion chamber integrated with the body lid; and

[0010] Fig. 8 is an example of a fluid ejection device with multiple fluid chambers and multiple expansion members.

[0011] Throughout the drawings, identical reference numbers designate similar, but not necessarily identical, elements. The figures are not necessarily to scale, and the size of some parts may be exaggerated to more clearly illustrate the example shown. Moreover the drawings provide examples and/or implementations in accordance with the description; however, the description is not limited to the examples and/or implementations provided in the drawings.

DETAILED DESCRIPTION

[0012] Printing devices may deposit a liquid print substance (referred to herein as printing fluid) on print media. In some examples, the printing device may include a fluid ejection device that deposits printing fluid. A fluid ejection device may include a fluidic die (also referred to as a printhead die) that includes nozzles to eject printing fluid. The fluid ejection device may also include a chamber to contain the printing fluid. This fluid chamber may provide the printing fluid to the nozzles on the fluidic die.

[0013] In some examples, the print substance may include printing agents or colorants. The printing device may apply the print substance to a substrate. A substrate is a superset of print media, such as plain paper, and can include any suitable object or materials to which a print substance from a printing device is applied including materials, such as powdered build materials, for forming three- dimensional articles. In addition, in some examples, a printing device may print on various media such as inanimate objects, skin, books, wood, plastic, metal, concrete, wallpaper, or other materials. Print substances, including printing agents and colorants, can include liquid inks, or other suitable marking material that may or may not be mixed with fusing agents, detailing agents, or other materials and can be applied to the substrate. [0014] In other examples, the printing device may be a fluid ejection device. For example, the printing device may be used in life-science applications (e.g., lab-on-chip fluidic designs), bio-printing, printed manufacturing features and sensors for additive manufacturing applications. These applications may use a print substance other than ink or toner.

[0015] In some cases, the fluid ejection device may receive printing fluid from a continuous ink supply system (CISS). In this case, printing fluid may be delivered to the fluid ejection device from an external reservoir.

[0016] In some examples, the fluid ejection device of a printing device may experience events than can result in a large amount of unintended printing fluid flowing out of the nozzles of the fluidic dies. This unintended printing fluid flow is referred to herein as drool. In these cases, the printing fluid may exit out of the nozzles of the fluidic die. For example, during certain events, a positive pressure may be generated within the fluid chamber of the fluid ejection device. For example, printing fluid may come out of the nozzles during a tip and/or tilt event or an event that can expand air inside the sealed part of the system.

[0017] As used herein, a tip event is an event where a printing device is tipped in an orientation that creates a head pressure from the external reservoir to the fluidic die. For example, in a normal orientation of the printing device, a negative pressure may exist between the fluidic die and the external reservoir. Flowever, if a positive pressure event occurs, printing fluid may be forced out of the nozzles of the fluidic die. Unintended printing fluid flowing out of the nozzles can cause many defects in the printing system. For example, this may result in inaccurate printing and may damage the fluidic die and other components of the printing device.

[0018] To counter drool due to a positive pressure event, the fluid ejection device may include an expansion member. In response to a positive pressure event, the expansion member may expand to receive air, and in some circumstances, printing fluid. The expansion of the expansion member may prevent positive pressure from building up within the fluid chamber to the point that printing fluid comes out of the nozzles of the fluid ejection device. [0019] Fig. 1 is a section view illustrating an example of a fluid ejection device 102 for a printing device that includes an expansion member 104. Examples of printing devices include printers, copiers, fax machines, multifunction devices including additional scanning, copying, and finishing functions, all-in-one devices, pad printers to print images on three dimensional objects, and three-dimensional printers (additive manufacturing devices).

[0020] In some examples, the fluid ejection device 102 may be used in a fluid ejection application (e.g., thermal inkjet, piezoelectric inkjet, etc.). For example, printing fluid may be stored in a fluid chamber 106. A fluidic die 112 may include nozzles and circuitry to eject the printing fluid out of the fluid ejection device 102.

[0021] In some examples, the fluid ejection device 102 may be included in a printing device that includes an external reservoir in a continuous ink supply system (CISS). In this case, printing fluid may be provided to the fluid ejection device 102 from the external reservoir (not shown). An example of this approach is described in connection with Fig. 2. In other examples, the printing fluid for the fluid ejection device 102 may be stored within the fluid chamber 106 of the fluid ejection device 102.

[0022] The fluid chamber 106 may be a sealed component of the printing device. For example, in the case of a CISS, the fluid chamber 106 may be pressurized with respect to the external reservoir. In this example, a negative pressure may be maintained during normal operation and orientation of the printing device.

[0023] In some cases, a positive pressure event may occur within the fluid chamber 106 of the fluid ejection device 102. For example, if the fluid ejection device 102 is tipped or tilted, printing fluid from the external reservoir may exert a positive pressure on the fluidic die 112. This may force printing fluid out of the nozzles of the fluidic die 112.

[0024] In another example, a positive pressure event may be an altitude change of the printing device. In this case, air pressure changes within the sealed system may create a positive pressure within the fluid chamber 106. For example, in the event where a printing device is subject to increases in altitude, a negative atmospheric pressure is exerted on the system. This causes the air in the sealed fluid ejection device 102 and tubes running from the fluid ejection device 102 to expand, resulting in a positive pressure within the fluid chamber 106.

[0025] The fluid ejection device 102 may include an expansion member 104 to relieve the positive pressure event in the fluid chamber 106. In some examples, the expansion member 104 may be a film material that prevents air infusion and/or fluid infusion. In other words, air may not pass through the film material forming the expansion member 104. In some examples, the expansion member 104 may be a bag or pouch to hold air and/or other fluids (e.g., printing fluid). As such, the expansion member 104 may use materials to prevent air and/or other fluids from passing through it. For instance, the expansion member 104 may be a formed from a metallic foil or polymer film-based bag or pouch. The expansion member 104 may be a flexible material such that the expansion member 104 may expand or contract with the flow of air or other fluid into or out of the expansion member 104.

[0026] In some examples, the expansion member 104 may include an opening or other fluidic interface to create a seal with the fluid chamber 106. Therefore, the fluid chamber 106 and the interior of the expansion member 104 are sealed from the atmosphere outside the fluid ejection device 102.

[0027] The expansion member 104 may be coupled to the fluid chamber 106 of the fluid ejection device 102. For example, the expansion member 104 may receive air from the fluid chamber 106 in response to a positive pressure event in the fluid chamber 106. An air connection element 110 may connect the expansion member 104 to the fluid chamber 106. The air connection element 110 may enable air transfer between the fluid chamber 106 and the expansion member 104.

[0028] If a negative pressure state is present within the fluid chamber 106, then the expansion member 104 compresses to approximately zero air volume. In other words, in response to negative pressure within the fluid chamber 106, air may exit out of the expansion member 104, which results in the expansion member 104 compressing to a minimum volume (e.g., zero volume). [0029] Expansion of the expansion member 104 may provide positive pressure relief in the fluid chamber 106 to prevent printing fluid from drooling out of a nozzle in the fluid ejection device 102. For example, if a positive pressure event occurs in the fluid chamber 106, then air in the fluid chamber 106 may flow into the expansion member 104. This airflow may cause the expansion member 104 to expand (e.g., inflate), which relieves pressure buildup within the fluid chamber 106, thus preventing drool of printing fluid out of the nozzles of the fluidic die 112.

[0030] In the example of tipping of the printing device, a certain amount of printing fluid may flow from the external reservoir into the fluid chamber 106. This flow of printing fluid into the fluid chamber 106 may result in a positive pressure. The expansion member 104 may expand to accommodate pressurized air in this scenario.

[0031] In an example of altitude changes, the expansion member 104 in the fluid ejection device 102 is allowed to expand to accommodate expanding air in the system. Without the pressure relief from the expansion member 104, the added pressure on the printing fluid contents in the fluid ejection device 102 may cause printing fluid to come out of the fluidic die 112, which may lead to print defects or a damaged printing device.

[0032] In some examples, the air connection element 110 may be integrated with the components forming the fluid ejection device 102. For example, the air connection element 110 may be a channel or other opening in the lid or manifold of the fluid ejection device 102 that connects the fluid chamber 106 to the expansion member 104.

[0033] In other examples, the air connection element 110 may be a separate component that attaches to other parts of the fluid ejection device 102. For example, the air connection element 110 may be a tube, pipe, ducting, hose or other structure that connects to both the fluid chamber 106 and the expansion member 104.

[0034] In yet another example, the expansion member 104 may connect directly to the fluid chamber 106. In this case, the air connection element 110 may be an opening in the fluid chamber 106 to which the expansion member 104 attaches to form an airtight seal.

[0035] In some examples, the expansion member 104 may also receive printing fluid in addition to air. For example, if the printing device is tipped to an extreme angle, printing fluid within the supply line of the printing device may exert enough pressure to enter the air connection element 110 and fill the expansion member 104. In this circumstance, the expansion member 104 may relieve positive pressure due to both the air and printing fluid in the fluid chamber 206. The expansion member 104 may also contain the extra printing fluid within the system, thus preventing unintended printing fluid flow out of the fluid ejection device 102.

[0036] In some examples, the fluid ejection device 102 may include an expansion chamber 108. The expansion chamber 108 may house the expansion member 104. The expansion chamber 108 may be a volume in which the expansion member 104 is located. The expansion chamber 108 may protect the expansion member 104 while providing the expansion member 104 room to expand and contract in response to pressure changes in the fluid chamber 106. [0037] The expansion chamber 108 may be vented to atmosphere outside the fluid ejection device 102. For example, the expansion chamber 108 may include a vent that allows air to flow into and out of the expansion chamber 108. In some examples, the vent may be an opening (e.g., hole). In other examples, the vent may include a valve.

[0038] In some examples, the expansion chamber 108 may be integrated with the body, as shown in Figs. 3 and 4. In other examples, the expansion chamber 108 may be integrated with a manifold of the fluid ejection device 102, as shown in Figs. 5 and 6. In yet other examples, the expansion chamber 108 may be integrated with the lid of the fluid ejection device 102, as shown in Fig 7. In yet other examples, the expansion chamber 108 may be a separate component that is attached to the body of the fluid ejection device 102.

[0039] In some examples, the expansion member 104 may be sized to accommodate a volume of printing fluid that may flow into the fluid chamber due to a positive pressure event. For example, if the printing device tips or tilts, a fixed amount of printing fluid may flow into the fluid chamber 106 from the supply lines of the external reservoir. In this case, the expansion member 104 may be sized to accommodate a volume of air corresponding to the pressure caused by this printing fluid flow. For example, if a volume of printing fluid is expected to flow into the fluid chamber 106 during a tipping event, the expansion member 104 may be sized to accommodate this volume to give enough margin in the system to prevent drool events.

[0040] Fig 2. is an example of a printing device 214 using an expansion member 204 to prevent printing fluid drool. The fluid ejection device 202 may be implemented in accordance with the fluid ejection device 102 described in connection with Fig. 1. For example, the fluid ejection device 202 may include an expansion member 204 connected to a fluid chamber 206 via an air connection element 210. The expansion member 204 may be located in an expansion chamber 208 that is vented to the atmosphere. The fluid ejection device 202 may include a fluidic die 212 to eject printing fluid 222 through nozzles.

[0041] In some examples, the printing device 214 may include an external reservoir 216 that is connected to the fluid ejection device 202 with a supply line 218. The external reservoir 216 may be part of a continuous ink supply system (CISS). In some examples, the supply line 218 may be a tube that delivers printing fluid to the fluid ejection device 202. The supply line 218 may deliver printing fluid to the fluid ejection device 202 at a negative pressure during normal operation of the printing device 214. The external reservoir 216, supply line 218, fluid chamber 206, air connection element 210 and the interior of the expansion member 204 may be sealed to the atmosphere.

[0042] In normal operation, the printing device 214 may be oriented such that the outlet of the external reservoir 216 is located below the inlet of the fluid ejection device 202. This may create a pressure head 220 resulting in a negative pressure within the fluid chamber 206. During a positive pressure event, a positive pressure may be introduced into the fluid chamber 206. For example, the printing device 214 may be tipped or tilted such that the printing fluid that is within the supply line 218, which would normally have to overcome the pressure head 220, may now flow into the fluid chamber 206. This printing fluid may exert a positive pressure within the fluid chamber 206. In another example, the printing device 214 may be moved from a low altitude to a high altitude. This change in altitude may cause the air in the sealed fluid chamber, supply line 218 and external reservoir 216 to expand, resulting in an increase in pressure.

[0043] The air in the fluid chamber 206 may flow into the expansion member 204 to relieve the positive pressure. The airflow into the expansion member 204 may cause the expansion member 204 to expand, which prevents a pressure buildup within the fluid chamber 206. The expansion of the expansion member 204 during a positive pressure event may prevent ejected printing fluid 222 from drooling out of the fluidic die 212.

[0044] It should be noted that the pressure relieving expansion member 204 may have close to zero air volume when compressed due to the negative pressure state of the printer printing fluid delivery system. The expansion member 204 may be contained in a vented area (e.g., the expansion chamber 208) of the body. The expansion member 204 may expand and relieve pressure from printing fluid and air when the printing device 214 is tipped or when the printing device 214 is taken through a pressure event that can expand air inside the system. This pressure relief can prevent printing fluid from drooling out of the nozzles.

[0045] Figs. 3 and 4 illustrate an example of a fluid ejection device 302 with an expansion chamber 308 integrated with the body 328. In this example, the body 328 may form a cavity for the fluid chamber 306, which provides printing fluid to a fluidic die 312.

[0046] The body 328 may also form the expansion chamber 308 for the expansion member 304. For example, a partition may separate the cavity of the fluid chamber 306 from the cavity of the expansion chamber 308.

[0047] In some examples, the expansion chamber 308 may include a vent 338 to the atmosphere. For example, the vent 338 may be a hole or other orifice to allow air to flow into and out of the expansion chamber 308. [0048] The fluid ejection device 302 may also include a body lid 326. When in an assembled configuration, the body lid 326 may be located on the body 328 such that the fluid chamber 306 is sealed.

[0049] The fluid ejection device 302 may also include a manifold 324 located on the body lid 326. The manifold 324 may include a printing fluid supply 336 to receive printing fluid from a supply line 218. The manifold 324, in conjunction with the body lid 326 may distribute printing fluid to the fluid chamber 306. For example, the manifold 324 may include fluidic channels that distribute printing fluid to different locations of the fluid chamber 306. Orifices in the body lid 326 may permit the printing fluid to flow into the fluid chamber 306. The body lid 326 may include a number of printing fluid ports 340. The manifold 324 and/or the body lid 326 may include routing to direct the printing fluid entering the printing fluid supply 336 to the printing fluid ports 340.

[0050] In some examples, the air connection element 310 may be formed by elements in the body lid 326, the manifold 324, or both. In the example illustrated in Figs. 3 and 4, the air connection element 310 includes a first opening 330 in the body lid 326. The first opening 330 is open to the fluid chamber 306. In some examples, the first opening 330 may be a hole through the body lid 326 such that when the body lid 326 is in the assembled configuration, the first opening 330 is located to open into the fluid chamber 306.

[0051] A second opening 332 in the body lid 326 may be located to open to the expansion member 304. The second opening 332 may also be positioned such that the expansion member 304 is located in the expansion chamber 308. [0052] A channel 334 in the manifold 324 may form a path for air transfer between the first opening 330 and the second opening 332. In some examples, the channel 334 may be formed by a raised area of the manifold 324. For instance, the manifold 324 may be molded to form the channel 334. In other examples, the channel 334 may be formed by routing in one surface (e.g., a bottom surface) of the manifold 324 without protruding through the opposite surface (e.g., top surface) of the manifold 324. When the manifold 324 is in the assembled configuration on the body lid 326, the first opening 330 and the second opening 332 may interface with the channel 334. It should be noted that in Fig. 4, the exterior surface of the air connection element 310 forming the channel 334 is visible. The interior of the channel 334 (as seen in Fig. 3) may allow air to pass between the expansion member 304 and the fluid chamber 306.

[0053] In some examples, the expansion member 304 may include a mechanism to attach to the body lid 326 at the second opening 332. For example, the expansion member 304 may include a flange, fitting or other fluid interface to form a sealed fluid connection with the second opening 332 to allow air and/or printing fluid to enter and exit the expansion member 304.

[0054] Figs. 5 and 6 illustrate an example of a fluid ejection device 502 with an expansion chamber 508 integrated with the manifold 524 of the fluid ejection device 502. In this example, the body 528 may form the cavity for the fluid chamber 506 and fluidic die 512, as described in connection with Figs. 3 and 4. [0055] In this example, the manifold 524 forms the expansion chamber 508 for the expansion member 504. For example, a cavity that projects from a bottom surface of the manifold 524 may form the expansion chamber 508. Therefore, the fluid chamber 506 in the body 528 is physically separated from the expansion chamber 508 in the manifold 524.

[0056] In some examples, the expansion chamber 508 on the manifold 524 may be open on one end to permit assembly of the expansion member 504 within the expansion chamber 508. An expansion chamber cover 548 may be placed over the opening of the expansion chamber 508 when in an assembled configuration. The expansion chamber 508 or the expansion chamber cover 548 or both may include a vent (not shown) to the atmosphere, as described in connection with Figs. 3 and 4.

[0057] The fluid ejection device 502 may also include a body lid 526 and a manifold 524. The body lid 526 may seal the fluid chamber 506. The manifold 524 may be located on the body lid 526 in an assembled configuration. In this example, the manifold 524 includes a printing fluid supply 536 to receive printing fluid from a supply line 218. The manifold 524, in conjunction with the body lid 526 distributes printing fluid to the fluid chamber 506 through fluidic channels and printing fluid ports 540. The manifold 524 and/or the body lid 526 may include routing to direct the printing fluid entering the printing fluid supply 536 to the printing fluid ports 540.

[0058] In this example, the air connection element is formed by elements in the body lid 526 and the manifold 524. A first opening 530 in the body lid 526 is open to the fluid chamber 506. In some examples, the first opening 530 may be a hole through the body lid 526 such that when the body lid 526 is in the assembled configuration, the first opening 530 opens into the fluid chamber 506.

[0059] The manifold 524 includes air routing 544 to direct air to a second opening 532 at the expansion member 504. The second opening 532 may be located at one end of the air routing 544 to form an opening through the manifold 524. The second opening 532 may also be positioned such that the expansion member 504 is located in the expansion chamber 508.

[0060] The air routing 544 may be a channel formed (e.g., molded, cut, etc.) in a surface (e.g., top surface) of the manifold 524 opposite the expansion chamber 508 and fluid chamber 506. The air routing 544 in the manifold 524 may form a path for air transfer between the first opening 530 and the second opening 532. An opening 552 may be located at an end of the air routing 544 opposite the second opening 532. When the manifold 524 is in the assembled configuration on the body lid 526, the first opening 530 of the body lid 526 may interface with the opening 552 of the air routing 544 of the manifold 524.

[0061] In some examples, an air routing cover 546 may attach to the manifold 524 to cover and seal the air routing 544. For example, the air routing cover 546 may be a plate that attaches to the manifold 524 to cover the air routing 544 to form a seal that allows air and/or printing fluid to enter and exit the expansion member 504.

[0062] In some examples, a stabilizing strap 550 may attach to the body 528 and the expansion chamber cover 548. The stabilizing strap 550 may prevent flexing or bending of the manifold 524 by restricting movement of the expansion chamber 508 relative to the body 528. In some examples, the stabilizing strap 550 may be a label, plate or film that is attached (e.g., bonded) between the body 528 and the expansion chamber cover 548.

[0063] It should be noted that in this example, the expansion chamber 508 and expansion member 504 are located on a back side of the fluid ejection device 502. In other examples, the expansion chamber 508 and expansion member 504 may be located on other sides (e.g., right side, left side, etc.) of the fluid ejection device 502.

[0064] Fig. 7 illustrates an example of a fluid ejection device 702 with an expansion chamber 708 integrated with a body lid 726. In this example, the body 728 may form the fluid chamber 706. However, in this example, the body lid 726 forms the expansion chamber 708 for the expansion member 704 with a structure and function as the expansion chamber 508 described in connection with Figs. 5 and 6. Therefore, in this example, the fluid chamber 706 in the body 728 is physically separated from the expansion chamber 708 on the body lid 726.

[0065] In some examples, the expansion chamber cover 748 may be placed over the opening of the expansion chamber 708 when in an assembled configuration, as described in connection with Figs. 5 and 6. The expansion chamber 708 or the expansion chamber cover 748 or both may include a vent (not shown) to the atmosphere.

[0066] When in an assembled configuration, the body lid 726 may be located on the body 728 such that the fluid chamber 706 is sealed. The manifold 724 may be located on the body lid 726 in the assembled configuration. In this example, the manifold 724 includes a printing fluid supply 736 and routing to distribute printing fluid to the fluid chamber 706 through fluidic channels and printing fluid ports 740, as described in connection with Figs. 5 and 6.

[0067] In this example, the air connection element is formed by elements in the body lid 726. For example, air routing 744 in the body lid 726 may direct air from a first opening 730 to a second opening 732. The first opening 730 in the body lid 726 is open to the fluid chamber 706. In some examples, the first opening 730 may be a hole through the body lid 726 such that when the body lid 726 is in the assembled configuration, the first opening 730 opens into the fluid chamber 706. The second opening 732 may be located at one end of the air routing 744 to form an opening through the body lid 726. The second opening 732 may also be positioned such that the expansion member 704 is located in the expansion chamber 708.

[0068] The air routing 744 may be a channel formed (e.g., molded, cut, etc.) in a surface (e.g., top surface) of the body lid 726 opposite the expansion chamber 708. The air routing 744 in the body lid 726 may form a path for air transfer between the first opening 730 and the second opening 732.

[0069] In some examples, the manifold 724 may be attached to the body lid 726 to cover and seal the air routing 744. For example, the manifold 724 may include a surface that covers the air routing 744 to form a seal that allows air and/or printing fluid to enter and exit the expansion member 704.

[0070] In some examples, a stabilizing strap 750 may attach to the body 728 and the expansion chamber cover 748 to restrict movement of the expansion chamber 708 relative to the body 728. As described in Fig. 5 and 6, the expansion chamber 708 and expansion member 704 may be located on other sides (e.g., right side, left side, etc.) of the fluid ejection device 702.

[0071] Fig 8. is an example of a fluid ejection device 802 with multiple fluid chambers 806a-c and multiple expansion members 804a-c. In this example, the fluid ejection device 802 may be used to print with different printing fluids. For example, the fluid ejection device 802 may be used for color printing where different colored printing fluids (e.g., cyan, yellow, magenta, etc.) may be used. [0072] In this example, the body 828 may form three distinct fluid chambers 806a-c. The body 828 also forms an expansion chamber 808 to contain three expansion members 804a-c.

[0073] A body lid 826 may include printing fluid ports 840a-c to allow printing fluid to enter the fluid chambers 806a-c. The printing fluid may be received from fluid supplies 836a-c on the manifold 824. For example, a first printing fluid supply 836a may supply printing fluid to a first printing fluid port 840a located above the first fluid chamber 806a. A second printing fluid supply 836b may supply printing fluid to a second printing fluid port 840b located above the second fluid chamber 806b. A third printing fluid supply 836c may supply printing fluid to a third printing fluid port 840c located above the third fluid chamber 806c.

[0074] The body lid 826 may also include air routings 844a-c to facilitate airflow between the fluid chambers 806a-c and the expansion members 804a-c. For example, a first air routing 844a may connect the first fluid chamber 806a to a first expansion member 804a. A second air routing 844b may connect the second fluid chamber 806b to a second expansion member 804b. A third air routing 844c may connect the third fluid chamber 806c to a third expansion member 804c. In this example, the manifold 824 may cover and seal the air routings 844a-c.

[0075] It should be noted that while various examples of systems and methods are described herein, the disclosure should not be limited to the examples. Variations of the examples described herein may be implemented within the scope of the disclosure. For example, functions, aspects, or elements of the examples described herein may be omitted or combined.

Claims

1. A fluid ejection device for a printing device, comprising: an expansion member coupled to a fluid chamber of the fluid ejection device, the expansion member to receive air from the fluid chamber in response to a positive pressure event in the fluid chamber.

2. The fluid ejection device of claim 1 , wherein the expansion member comprises a film material that prevents air infusion.

3. The fluid ejection device of claim 1 , wherein the expansion member relieves the positive pressure event in the fluid chamber.

4. The fluid ejection device of claim 1 , wherein the positive pressure event comprises tipping of the fluid ejection device or an altitude change.

5. The fluid ejection device of claim 1 , wherein expansion of the expansion member provides positive pressure relief in the fluid chamber to prevent printing fluid from drooling out of a nozzle in the fluid ejection device.

6. The fluid ejection device of claim 1 , wherein the expansion member compresses to approximately zero air volume in response to a negative pressure state in the fluid chamber.

7. A fluid ejection device for a printing device, comprising: a fluid chamber to provide printing fluid to a fluidic die; an expansion member coupled to the fluid chamber, the expansion member to receive air from the fluid chamber in response to a positive pressure event in the fluid chamber; and an expansion chamber to house the expansion member.

8. The fluid ejection device of claim 7, further comprising an air connection element for air transfer between the fluid chamber and the expansion member.

9. The fluid ejection device of claim 8, wherein the air connection element comprises: a first opening in a body lid, the first opening being open to the fluid chamber; a second opening in the body lid, the second opening being open to the expansion member; and a channel in a manifold that attaches to the body lid, the channel forming a path for air transfer between the first opening and the second opening.

10. The fluid ejection device of claim 7, wherein the expansion chamber is vented to atmosphere and the fluid chamber and interior of the expansion member are sealed from the atmosphere.

11. The fluid ejection device of claim 7, wherein a body forms the fluid chamber and the expansion chamber.

12. The fluid ejection device of claim 7, wherein a body forms the fluid chamber and a manifold forms the expansion chamber.

13. The fluid ejection device of claim 7, wherein a body forms the fluid chamber and a body lid forms the expansion chamber.

14. A printing device, comprising: an external reservoir; and a fluid ejection device coupled to the external reservoir, the fluid ejection device comprising: a fluid chamber to receive printing fluid from the external reservoir, and an expansion member coupled to the fluid chamber of the fluid ejection device, the expansion member to receive air from the fluid chamber in response to a positive pressure event in the fluid chamber.

15. The printing device of claim 14, wherein the external reservoir is included in a continuous ink supply system (CISS).