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Title:
AIR PURGE DEVICES FOR PRINTING DEVICES
Document Type and Number:
WIPO Patent Application WO/2019/190496
Kind Code:
A1
Abstract:
An air purge device for a printing device includes a piston assembly and an actuator. The piston assembly is to form a fluid connection with a fluidic interconnect assembly of the printing device. The actuator is to support the piston assembly and is movable to release the piston assembly to purge air from the fluidic interconnect assembly.

Inventors:
TEO CHERNG LINN (SG)
CHEN GING ZHAO (SG)
ONG VINCENT (SG)
Application Number:
US2018/024776
Publication Date:
October 03, 2019
Filing Date:
March 28, 2018
Export Citation:
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Assignee:
HEWLETT PACKARD DEVELOPMENT CO (US)
International Classes:
B41J2/215
Foreign References:
US5847734A1998-12-08
JP2013233675A2013-11-21
US20170320331A12017-11-09
CN202645936U2013-01-02
Attorney, Agent or Firm:
HOOPES, Benjamin E. (US)
Download PDF:
Claims:
We claim:

1. An air purge device for a printing device, toe air purge device comprising: a body unit to engage with a fluidic interconnect assembly of toe printing device;

a piston assembly comprising a piston and a resilient element disposed in toe piston, wherein toe piston assembly is to engage with toe body unit to form a fluid connection with the fluidic interconnect assembly; and

an actuator to couple to the body unit and support the piston assembly with the resilient dement compressed, wherein the actuator is movable to cause the resilient element to expand and move toe piston assembly to purge air from toe fluidic interconnect assembly.

2. The air purge device of claim 1, wherein the body unit comprises a tower, the tower comprising:

a first hollow cylindrical part to engage with the fluidic Interconnect assembly;

a second hollow cylindrical part to engage with the piston assembly; and a barrier plate between the first hollow cylindrical part and the second hollow cylindrical part, Wherein the barrier plate comprises a pin hole to form toe fluid connection between the piston assembly and toe fluidic interconnect assembly.

3. The air purge device of claim 2, wherein toe piston comprises a rim at a first end and a groove below the rim, the resilient element being disposed in the first end of the piston and the first end of the piston being disposed in the second hollow cylindrical part of the tower, and wherein an O-ring is disposed in toe groove to form a seal between the piston and the second hollow cylindrical part.

4. The air purge device of claim 1 , wherein

the body unit comprises a plurality of towers,

the air purge device comprises a plurality of piston assemblies, each piston assembly corresponding to a tower of the plurality of towers, and the actuator is to couple to the body unit and support the plurality of piston assemblies, and is movable to release the plurality of piston assemblies.

5. The air purge device of claim 1, wherein

the body unit comprises a plurality of towers, and

the piston assembly Is to engage with the plurality of towers through a connector.

6. The air purge device of claim 1 further comprising a base cover, wherein the base cover is to support the actuator on coupling of toe actuator to the body unit and to support the piston assembly on removal of the actuator from the body unit.

7. A printing device comprising:

a printhead holding assembly comprising a manifold to engage with a fluidic interconnect assembly to deliver print fluid to a printhead; and

an air purge device comprising:

a body assembly coupled to the printhead holding assembly at a mounting location of the printhead, the body assembly comprising a piston assembly in fluid connection with the fluidic interconnect assembly, wherein the piston assembly is loaded with a spring; and

an actuator coupled to the body assembly to support the piston assembly with the spring cornpressed, wherein the actuator is to be decoupled from the body assembly to release tile piston assembly and purge air from the fluidic interconnect assembly.

8. The printing device of claim 7, wherein toe body assembly comprises a body unit to engage with the fluidic interconnect assembly on a first side of the body unit, wherein toe body unjt comprises a hollow cylindrical part on a second side of the body unit, and wherein toe piston assembly is disposed in the hollow cylindrical part.

9. The printing device of claim 8, wherein the body unit comprises a pin hole to form the fluid connection between the fluidic interconnect assembly on the first side and the piston assembly in the hollow cylindrical part on the second side.

10. The printing device of claim 7, wherein the body assembly comprises a base cover to support the piston assembly in response to a movement of the piston assembly on removal of the actuator.

11. The printing device of claim 7, wherein the manifold fcs movable about a hinge on removal of the actuator to allow removal of the body assembly from the mounting location of foe printhead and installation of foe printhead at foe mounting location.

12, A printing device comprising:

a printhead holding assembly coupled to a fluidic interconnect assembly; and

an air purge device coupled to the printhead holding assembly, wherein foe air purge device comprises:

a body unit having a plurality of towers, wherein each tower comprises:

a first hollow cylindrical part on a first side of the body unit to engage with foe fluidic interconnect assembly,

a second hollow cylindrical part on a second side of the body unit; and

a barrier plate between foe first hollow cylindrical part and foe second hollow cylindrical part, the barrier plate comprising a pin hole;

a plurality of piston assemblies, a piston assembly corresponding to a tower of the plurality of towers and in fluid connection with foe fluidid interconnect assembly through the pin hole in foe barrier plate of foe tower, wherein foe piston assembly comprises a piston and a spring, wherein a first end of foe spring is disposed in the piston and a second end of the spring is disposed in foe second hollow cylindrical part of a corresponding tower; and an actuator coupled to the body unit to support the plurality of piston assemblies with respective springs compressed, wherein toe actuator is removable to release the plurality of piston assemblies to purge air from the fluidic interconnect assembly.

13. The printing device of claim 12, wherein the printhead holding assembly comprises a manifold to engage with a plurality of fluid delivery needles of the fluidic interconnect assembly, a fluid delivery needle to engage with toe pin hole of a corresponding tower, wherein removal of the actuator Is to cause purging of the air from toe fluidic interconnect assembly through the fluid delivery needle and a corresponding pin hole into a corresponding piston assembly.

14. The printing device of claim 12, wherein the air purge device further comprises a base cover, wherein toe base cover is to support toe actuatoron coupling of toe actuator to the body unit and to support toe plurality of piston assemblies on removal of the actuator.

15. The (Minting device of daim 12, wherein the air purge device is removable from toe printhead holding assembly to allow coupling of printheads in place of toe air purge device.

Description:
AIR PURGE DEVICES FOR PRINTING DEVICES

BACKGROUND

[0001] Some printers may use printheads mounted on a carriage and may deposit a printing fluid, such as an ink or a 3D binding solution on a print media or build material, respectively. For instance, in one case, printing fluid tanks may act as reservoirs to feed printing fluid to printheads for printing. Printing fluid supply tubes are used to supply printing fluid to the printheads from the printing fluid tanks through regulators provided on the carriage. The number of printing fluid tanks and printing fluid supply tubes used are typically equal to the number of printing fluid colors and/or binding solutions used in the printer. Hie regulators help to control the printing fluid flow into the printheads.

BRIEF DESCRIPTION OF DRAWINGS

[0002] The following detailed description references die figures, wherein:

[0003] Fig. 1 illustrates an air purge device, in accordance with an example implementation of the present subject matter.

[0004] Fig. 2 illustrates a printing device with an air purge device, in accordance with an example implementation of the present subject matter.

[0005] Fig. 3 illustrates a printing device with an air purge device, in accordance with an example implementation of the present subject matter. iPOdei Fig. 4 illustrates a printhead holding assembly coupled to an air purge device, in accordance with an example implementation of the present subject matter.

[0007] Fig. 5 illustrates a printhead holding assembly coupled to an air purge device with the actuator removed, in accordance with an example implementation of the present subject matter.

[0008] Fig. 6 illustrates a manifold section of a printhead holding assembly decoupled from a body assembly of an air purge device, in accordance with an example implementation of the present subject matter. [0009] Fig. 7 illustrates another view of a manifold section of a printhead holding assembly decoupled from a body assembly of an air purge device, in accordance with an example implementation of tire present subject matter.

[0010] Figs. 8A and 8B illustrate an air purge device with a body assembly coupled to an actuator, in accordance with an example implementation of the present subject matter.

[0011] Figs. 9A and 9B illustrate a body assembly of an air purge device decoupled from an actuator, in accordance with an example implementation of the present subject matter.

[0012] Figs. 10A and 10B illustrate different views of a body unit of an air purge device, in accordance with an example implementation of the present subject matter.

[0013] Figs. 11A-11C illustrate components of a piston assembly of an air purge device, in accordance with an example implementation of tire present subject matter.

[0014] Fig. 12 illustrates components of a piston assembly, in accordance with an example implementation of the present subject matter.

[0015] Fig. 13 illustrates a base cover of an air purge device, in accordance with an example implementation of the present subject matter.

[0016] Figs. 14 illustrates an actuator of an air purge device, in accordance with an example implementation of the present subject matter.

DETAILED DESCRIPTION

[0017] In printers with separate printing fluid tanks and printheads, printing fluid tanks act as a (Minting fluid source for printheads. The assembly of components forming the path of (Minting fluid flow from the printing fluid tanks to the printhead is referred to herein as a fluidic interconnect assembly.

[0018] In some cases, the fluidic interconnect assembly may not initially contain printing fluid, but may be empty and may contain air. During set-up and initialization of the printer, air is to be removed from, and printing fluid is to be drawn into, the fluidic interconnect assembly before foe printhead may be used for printing, in some cases, air from the fluidic interconnect assembly tends to occupy the space in a printing fluid container of a printhead as foe printing fluid is consumed and reduces the space available for printing fluid to flow in from the printing fluid tanks. Hence, air from the fluidic interconnect assembly may be removed (e.g., purged) before installation of the printheads. Typically, pump and valve systems or recirculation systems are used for this purpose.

[0019] Various aspects of the present subject matter relate to air purge devices for printing devices. Example air purge devices discussed herein may be relatively ample and cost effective to implement and may be used with a variety of printing devices. For instance, an example air purge device may be initially coupled to a printing device at a mounting location of a printhead (e > g., such as during shipping of the product device), and may engage with a fluidic interconnect assembly of the printing device. The fluidic interconnect assembly may in turn engage with printing fluid tanks (e.g., such as may be filled after shipping and during a setup process). The air purge device may indude an actuator that, on actuation, can create a suction force and draw out air from the fluidic interconnect assembly. This also results in printing fluid being drawn into the fluidic interconnect assembly from foe printing fluid tanks. Further, the actuation of foe actuator may allow access to a manifold of foe printing device to allow removal of foe air purge device. Subsequently, the air purge device can be removed from foe printing device and the printhead can be mounted instead to engage with foe fluidic interconnect assem bly .

[0020] In one example, to create the suction force, the air purge device may indude a piston assembly to engage with the fluidic interconnect assembly. The pistol assembly may indude a piston and a resilient element, such as a spring, disposed in the piston. The actuator may support the piston assembly with foe resilient element compressed and rnay be movable to cause foe resilient element to expand. As the resilient member expands, it may move the piston assembly, thereby creating foe suction force to purge air from the fluktic interconnect assembly. [0021] Ulus, without using pumps or valves or other complex mechanisms, the air in the fluidic interconnection assembly may be easily purged at the time of printer installation. For example, the purging of air may also be performed by a user based on instructions provided in an installation manual, without the help of a technician. Further, the use of the piston assembly with a resilient element, such as a spring, to draw out the air thorn the fluidic interconnect assembly results in an efficient and quick removal of air. Moreover, as the air purge device is initially coupled at the mounting location of the printhead, it ensures that the air is purged first before the printhead is installed. Furthermore, the air purge device of the present subject matter may be retrofitted to and used with existing printer designs.

[0022] The following description refers to the accompanying drawings. While several examples are described in the description, modifications, adaptations, and other implementations are possible. Accordingly, the following detailed description does not constrain the scope of the disclosed examples. Instead, the proper scope of the disclosed examples may be defined by the appended claims. Wherever possible, the same reference numbers are used in the figures and the following description to refer to the same or similar parts for ease of understanding.

[0023] Fig. 1 illustrates an air purge device in accordance with an example implementation of the present subject matter. An air purge device 100 includes a body unit 102 to engage with a fluidic interconnect assembly 104 of a printing device 106. The air purge device 100 also includes a piston assembly 108 to engage with the body unit 102 to form a fluid connection with the fluidic interconnect assembly 104. As will be understood, a fluid connection refers to a connection that includes a fluid pathway, but may not indude a physical connection. Thus, presence of a fluid connection between the piston assembly 108 and the fluidic interconnect assembly 104 indicates that a fluid pathway may exist between the piston assembly 108 and the fluidic interconnect assembly 104, but a physical connection may not be present between the two. For instance, other components may be arranged between piston assembly 108 and fluidic interconnect assembly 104, by way of example. [0024] Hie piston assembly 108 includes a piston 110 and a resilient element 112 disposed in toe piston 110. The resilient element 112 may be, tor example, a spring, a tubular rubber element, or the like.

[0025] Further, an actuator 114 is provided to couple to toe body unit 102 and support the piston assembly 108 with the resilient element 112 compressed. The actuator 114 may move (e.g., may be removable) to cause the resilient element 112 to expand and move the piston assembly 108. As the piston assembly 108 moves, a suction force is created, due to which air is drawn out from, and printing fluid is drawn into, the fluidic Interconnect assembly 104.

[0026] In one example, the air purge device 100 may further include a base cover (not shown in this figure) to support the actuator 114 on coupling of the actuator 114 to the body unit 102 and to support the piston assembly 108 in response to actuation of the actuate»· 114 (e.g., on removal of the actuator 114 from the body unit 102).

[002h In various example implementations, toe body unit 102 may include a tower (not shown in this figure) to engage with the piston assembly 108. In an example, the body unit 102 may include a plurality of towers and the air purge device 100 may include a plurality of piston assemblies, a piston assembly 1C® corresponding to a tower of the plurality of towers. Accordingly, toe actuator 114 may couple to the body unit 102 and support the plurality of piston assemblies and may be movable to release the plurality of piston assemblies.

[0028] In another example, the body unit 102 may ihc!ude a plurality of towers and toe piston assembly 108 is to commonly engage with toe plurality of towers through a connector. For example, the connector may be a manifold -I ike arrangement to which toe plurality of towers is connected on one side and the pistol assembly 108 is connected on another side. In another example, the connector may include tubular extensions that commonly connect toe plurality of towers to toe piston assembly 108.

[0029] Thus, the air purge device 100 according to various aspects of toe present subject matter may be deployed with printing devices to easily and efficiently purge air prior to printhead installation. [0030] Fig.2 illustrates a printing device 200, in accordance with an example implementation of the present subject matter. The printing device 200 may be an example implementation of the printing device 106.

[0031] The printing device 200 includes a printhead holding assembly 202 comprising a manifold 204 to engage with the fluidic interconnect assembly 104. The manifold 204 helps in engaging the fluidic interconnect assembly 104 with printheads for delivery of print fluid. The printing device 200 further indudes the air purge device 100.

[0032] In one example, the air purge device 100 indudes a body assembly 208 coupled to the printhead holding assembly 202 at a mounting location of the printhead. The body assembly 208 indudes the piston assembly 108 in fluid connection with the fluidic interconnect assembly 104. In one example, the piston assembly 108 is loaded with a spring 210, which acts as the resilient element 112.

[0033] The air purge device 100 further indudes the actuator 114 coupled to the body assembly 208 to support the piston assembly 108 with the spring 210 compressed. Further, the actuator 114 is movable to release the piston assembly 108 to purge air from the fluidic interconnect assembly 104. For example, foe actuator may be decoupled from the body assembly 208 to release the piston assembly 108.

[0034] In an example implementation, the body assembly 208 includes the body unit 102, the piston assembly 108, and the base cover (not shown in this figure). The body assembly 208 may be initially coupled to the printhead holding assembly 202 at a mounting location where a printhead may be otherwise installed. The actuator 114 may be in turn coupled to the body assembly 208 to support the piston assembly 108 with the spring 210 compressed.

[0035] in operation, to purge air from the fluidic interconnect assembly 104 and install the printhead in the printhead holding assembly 202, a user may first actuate actuator 114 (e.g., remove the actuator 114 from the body assembly 208). This releases the spring 210, thereby causing the piston assembly 108 to move. As a result, a suction force is created which purges the air from the fluidic interconnect assembly 104 through the fluid connection between the piston assembly 108 and the fluidic interconnect assembly 104. Once the air is purged, the user may move the manifold 204 about a hinge to access and remove die body assembly 208 from the mounting location of the printhead on the printhead holding assembly 202. Subsequently, the printhead may be mounted at the same mounting location, thereby establishing a fluid connection with the fluidic interconnect assembly 104 to receive the print fluid for printing.

[0036] It will be understood that the printing device 200 may indude various other assemblies and components, such as print medium feeding and receiving trays, print medium moving assembly, mounting assemblies, electronic controllers, power supply, and the like, which are not shown here for brevity. Such other assemblies and components may work in conjunction with the printhead holding assembly for carry ng out print operations.

[003h Fig. 3 illustrates a printing device 300, in accordance with an example implementation of foe present subject matter. It will be understood that printing device 300 is an example implementation of the printing device 200.

[0038] In one example, foe printing device 300 indudes the printhead holding assembly 202 coupled to foe fluidic interconnect assembly 104. Further, foe air purge device 100 may be coupled to the printhead holding assembly 202. The air purge device 100 indudes foe body unit 102, a plurality of piston assemblies 108-1...108-n, individually referred to as piston assembly 108, and the actuator 114 coupled to the body unit i02 to support the plurality of piston assemblies.

[0039] In one example, foe body unit 102 may indude a plurality of towers,

302-1...302-n. individually referred to as tower 302. A tower 302 of the body unit 102 may correspond to a piston assembly 108 of foe plurality of piston assemblies. A tower 302 may indude a first hollow cylindrical part 304 on a first side of the body unit 102 to engage with the fluidic interconnect assembly 104, a second hollow cylindrical part 306 on a second side of foe body unit 102 to engage with a piston assembly 108, and a barrier plate 308 between foe first hollow cylindrical part 304 and the second hollow cylindrical part 306. Further, the barrier plate 308 may indude a pin hole to form a fluid connection between the piston assembly 108 and foe fluidic interconnect assembly 104. [0040] Furthermore, each piston assembly 108 may include toe piston 110 and the spring 210. A first end of toe spring 210 may be disposed in toe piston 110 and a second end of the spring may be disposed in toe second hollow cylindrical part 306 of the corresponding tower 302. The actuator 114 may support toe plurality of piston assemblies with their respective spring 210 compressed. Further, the actuator 114 may be movable, for example, may be removed, to release the plurality of piston assemblies to purge air from toe fluidic interconnect assembly 104.

[0041] In one example, the fluidic interconnect assembly 104 includes a plurality of fluid delivery needles (not shown in this figure), a fluid delivery needle corresponding to a tower 302. Each fluid delivery needle may engage with the pin hole of a corresponding tower 302 to form toe fluid connection between the fluidic interconnect assembly 104 and the piston assembly 108 corresponding to the tower 302. Thus, in one example, the removal of the actuator may cause the purging of air from the fluidic interconnect assembly 104 through a fluid delivery needle and corresponding pin hole into the corresponding piston assembly 108.

[0042] Further, as discussed above, the air purge device 100 may be removable from toe printhead holding assembly 202 to allow coupling of printheads in place of toe air purge device 100 after toe air has been purged from the fluidic interconnect assembly 104.

[0043] It will be understood that the printing device 300 may also include various other assemblies and components, arch as print medium feeding and receiving trays, print medium moving assembly, mounting assemblies, electronic controllers, power supply, and the like, which are not shown here for brevity. Such other assemblies and components may work in conjunction with the printhead holding assembly for carrying out print operations.

[0044] Various aspects of the present subject matter will be further discussed with reference to Figs. 4-14 as example implementations. While the Figs. 4-14 illustrate example implementations where the air purge device has a plurality of towers and a plurality of piston assemblies, a piston assembly corresponding to a tower, it will be understood that different variations of number of towers and piston assemblies are possible. Further, it will be understood that other features and combinations of the features that may be evident based on the teachings of the present subject matter are also intended to be cowed in the scope of the claims appended herein though not explicitly illustrated in the example implementations.

[0045] Fig, 4 illustrates a printhead holding assembly 202 coupled to an air purge device 100, in accordance with an example implementation of the present subject matter.

[0046] The printhead holding assembly 202 includes a manifold 204 that engages with a fluidic interconnect assembly 104 to transfer printing fluid from printing fluid tanks to printheads. Hie manifold 204 Includes a first plurality of towers, such as towers 402-1 , 402-2, ...402-4, individually referred to as first tower 402, that engage with the fluidic interconnect assembly 104. Further, the tower

402 of the first plurality of towers engages with the tower 302 (not shown in this figure) of the air purge device 100.

[0047] The air purge device 100 includes a body unit 102 and an actuator 114 that is coupled to the body unit 102. In one example, the air purge device 100 is coupled to the printhead holding assembly 202 such that the actuator 114 of the air purge device 100 hinders opening of the manifold 204. This ensures that the manifold 204 may be accessed and opened after the actuator 114 has been actuated and air has been purged from the fluidic interconnect assembly 104.

[0048] The actuator 114 supports piston assemblies (not shown in tills figure) in the air purge device 100 and is in turn supported by a base cover 404. In one example, the body unit 102, the piston assemblies, and the base cover 404 may be together referred to as body assembly 208.

[0049] As illustrated, the actuator 114 includes a protruding handle portion 406 to allow a user to grip and move the actuator 114 for purging air from the fluidic interconnect assembly 104. For example, the actuator 114 may be removed or decoupled from the body unit 102 for actuation. [0050] Fig. 5 illustrates the printhead holding assembly 202 coupled to the body assembly 208 of the air purge device 100 with the actuator 114 removed, in accordance with an example implementation of toe present subject matter.

[0051] On removal of the actuator 114, piston assemblies 108-1...108-n of the air purge device 100 get actuated and move towards toe base cover 404. This causes purging of the air from the fluidic interconnect assembly 104. Further, a manifold flap 504 that was behind toe handle portion 406 of toe actuator 114 becomes accessible. In one example, the manifold flap 504 may be accommodated in a recess present in the handle portion 406 of the actuator 114 when the air purge device 100 including toe actuator 114 is coupled to the printhead holding assembly 202.

[0052] When, the actuator 114 is removed, the manifold flap 504 may be used to move the manifold 204 about a hinge in toe direction of arrow 506 to provide access to toe body assembly 208; in one example, pressing the manifold flap 504 downwards, towards the base cover 404, may release a lock of the manifold 204 and allow the manifold 204 to be opened by moving in the direction of toe arrow 506.

[0053] The body unit 102 of the body assembly 208 includes a body flap 508 that may be used to remove toe body assembly 208 from toe printhead holding assembly 202. For example, the body flap 508 may be accommodated substantially behind or below the manifold flap 504 and may become accessible upon opening of the manifold 204. In one example, the body flap 508 may be pressed downwards, towards toe base cover 404, and may be used to provide a rotational movement to toe body assembly 208 to remove toe body assembly 208, including toe body unit 102, the piston assemblies 108-1...108m, and the base cover 404, from the printhead holding assembly 202. The body assembly 208 may be then replaced by the printheads in the printhead holding assembly 202 for printing operation.

[0054] Fig. 6 illustrates a manifold section 600 of toe printhead holding assembly 202 (shown in fig. 5) decoupled from the body assembly 208 of toe air purge device 100, in accordance with an example implementation of the present subject matter,

[0055] The manifold section 600 of the printhead holding assembly 202 indudes the manifold 204, the fluidic interconnect assembly 104, and a guide 602. The guide 602 may be used to guide the coupling of the air purge device 100, and of the body assembly 208 of the air purge device 100, at the mounting location of toe printheads in the printhead holding assembly 202. Subsequently, toe guide 602 may help with installation of the printheads at the mounting location after removal of the air purge device 100. As discussed above, the air purge device 100 may be removed in two steps, i.e., first the actuator 114 may be removed followed by removal of the body assembly 208.

[0056] As illustrated, the body unit 102 in toe body assembly 208 includes a plurality of towers 302-1 , 302-2...302-4, also referred to as a second plurality of towers, which may engage with a respective tower of a first plurality of towers 402-1 , 402-2, ...402-4 present on the manifold 204.

[0057] In one example, the manifold section 600 is to hold a color printing fluid printhead with the help of a first portion 604-1 of toe guide 602 and a black printing fluid printhead with the help of a second portion 604-2 of toe guide 602. In one example, toe color printing fluid printhead uses three colors, such as cyan, magenta, and yellow (CMY) for printing, while toe blade printing fluid printhead uses a single color, blade, fey printing. Accordingly, a first part of the manifold 204 corresponding to the first portion 604-1 includes three of the first plurality of towers and is to engage with a color printing fluid supply section of toe fluidic interconnect assembly 104. Similarly, a second part of the manifold 204 corresponding to toe second portion 604-2 indudes one of toe first plurality of towers and is to engage with a black printing fluid supply section of the fluidic interconnect assembly 104. Correspondingly, toe body unit 102 includes three towers, 302-1 , 302-2, 302-2 on one side and one tower 302-4 on toe other side to engage with toe corresponding tower 402 of the first plurality of towers.

[0058] It will be understood that toe manner of distribution of toe first plurality of towers on toe manifold 204 and the towers on toe body unit 102 is provided as an example and various other manners of distribution may be possible, though not explicitly disclosed herein.

[0059] Further, while the body unit 102 has been illustrated as a single unit, it will be understood that the body unit 102 may include two separate units, each with a set of towers to engage with a set of piston assemblies. For instance, one of the separate units may be used to purge air from the color printing fluid supply section of toe fluidic interconnect assembly 104 that is connected to toe first part of the manifold 204 and the other separate unit may be used to purge air from the black printing fluid supply section of the fluidic interconnect assembly 104 that is connected to toe second part of the manifold 204.

[0060] F$g- 7 illustrates another view of the manifold section 600 decoupled from the body assembly 208 of the air purge device 100, in accordance with an example implementation of the present subject matter.

[0061] A needle of a plurality of needles 702-1, 702-2, 702-3, 702-4, of the fluidic interconnect assembly 104, may engage with each of toe first plurality of towers 402-1 , 402-2, 402-3, 402-4, (for example, see fig. 6) on toe manifold 204. The needle of the plurality of needles 702-1 , 702-2, 702-3, 702-4 may be individually referred to as needle 702. Each needle 702 may in turn engage with a tower 302 on the body unit 102. Thus, toe body unit 102 may engage with toe fluidic interconnect assembly 104 through tine plurality of needles 702-1 , 702-2, 702-3, 702-4, in one example.

[0062] Figs. 8A and 8B illustrate the air purge device 100 with toe body assembly 208 coupled to toe actuator 114, in accordance with ain example implementation of the present subject matter. As shown, toe actuator 114 indudes projections 802 to provide frictional force for holding the actuator 114 in place on being coupled to the body assembly 208. The projections 802 may be formed as elongated bars in one example.

[0063] Fig. 8B illustrates a sectional view of the air purge device 100 to show a piston assembly 108 engaging with a tower of the body unit 102 and the actuator 114 supporting toe piston assembly 108, the actuator 114 in turn being supported by the base cover 404. In this state, toe resilient element 112 of the piston assembly is disposed in the piston 110 in a compressed state and is not visible in the figure.

[0064] Figs. 9A and 98 illustrate the body assembly 208 of the air purge device 100 decoupled from the actuator 114, in accordance with an example implementation of the present subject matter. The piston assemblies 108-1, 108- 2..108-4 get released on removal of the actuator 114 and are supported by the base cover 404.

[0065] Fig. 98 illustrates a sectional view of the body assembly 208 to show the piston assembly 108 with toe resilient element 112, such as a spring, in an expanded state and the piston 110 that has moved towards toe base cover 404 due to toe expansion of the resilient element 112.

[0066] Figs. 10A and 108 illustrate different views of the body unit 102 of the air purge device 100, in accordance with an example implementation of the present subject matter. The body unit 102 indudes the towers 302-1 , 302-2, 302- 3, 302-4. A tower 302 indudes a first hollow cylindrical part 304, such as 304-1 , 304-2, 304-3, 304-4, on a first side of the body unit 102 to engage with toe fluidic interconnect assembly 104. The tower 302 also indudes a second hollow cylindrical part 306, such as 306-1 , 306-2, 306-3, 306-4, on a second side of toe body unit 102 to engage with the piston assembly 108. Further, a barrier plate 308, such as 308-1 , 308-2, 308-3, 308-4, between the first hollow cylindrical part 304 and toe second hollow cylindrical part 306. In one example, a top date 1000 of the body unit 102 may ad as the barrier plate between toe first hollow cylindrical part 304 and the second hollow cylindrical part 306. The barrier plate 308 indudes a pin hole 1002 to form the fluid connedion between toe piston assembly 108 and the fluidic interconnect assembly 104.

(006h In one example, the second hollow cylindrical part 306 may be larger in diameter than the first hollow cylindrical part 304 to allow for engaging with the piston assembly 108. Hence, the second hollow cylindrical part 306 may be disposed at an offset from the corresponding first hoi tow cylindrical part 304. Therefore, the pin hole 1002 in the barrier plate 308 may be placed eccentrically with reference to the second hollow cylindrical part 306, but may be present centrally with reference to the first hollow cylindrical part 304. White the pin hole 1002 is visible in the second hollow cylindrical part 306-2, it will be understood that the other second hollow cylindrical parts 306-1, 306-3, 306-4 also Indude a pin hole 1002 in the respective barrier plates 308, though not visible in this figure.

[0068] In one «cample, when a part of the body unit 102 includes a single tower 302 to couple to a single piston assembly 108, a guide pin housing 1004 may be provided to house a guide pin (not shown in this figure) to ensure that toe piston assembly 108 does not undergo rotational movement when the piston assembly 108 is released on removal of toe actuator 114.

[0069] In one example, the body unit 102 indudes extensions 1006-1 and 1006-2 to couple to projections on the base cover 404 so that the base cover 404 does not move relative to toe body unit 102 when toe piston assembly 108 is released on removal of the actuator 114.

[0070] White not described, it will be understood that toe body unit 102 indudes various walls and coupling features to allow toe body unit 102 to couple to toe printhead holding assembly 202, the piston assemblies, and the base cover 404. Further, though toe body unit 102 has been illustrated as a single unit, toe body unit 102 may include multiple separate units as discussed earlier. Moreover, while toe body unit 102 has been shown as induding a plurality of towers in a particular arrangement, it will be understood that the body unit 102 may have different number of towers in different arrangements. For example, the body unit 102 may have a single tower 302 to engage with the manifold 204 or toe fluidic interconnect assembly 104.

[0071] Figs. 11A-11C illustrate components of piston assemblies of the air purge device 100, in accordance with an example implementation of toe present subject matter. Fig. 11A and 11B illustrate support plates 1102 and 1104, respectively, for supporting various pistons to form toe piston assemblies.

[0072] In one example, support plate 1102 is to support three piston assemblies to purge air from toe part of the fluidic interconnect assembly 104 corresponding to toe color printhead through the part of the body unit 102 having three towers as discussed above. Accordingly, the support plate 1102 includes three piston bases 1106-1 , 1106-2, and 1106-3 on which die pistons may be fitted. In one example, support plate 1104 is to support one piston assembly to purge air from toe part of the fluidic interconnect assembly corresponding to the black printhead through the part of the body unit 102 having one tower as discussed above. Accordingly, the support plate 1104 indudes one piston base 1106-4. In one example, to avoid rotational movement of the support plate 1104 when toe piston assembly moves, the support plate 1104 is made elongated and a guide pin 1108 is provided alongside the piston base 1106-4. The guide pin 1108 may be accommodated in the guide pin housing 1004 as discussed earlier to avoid rotational movement of the piston assembly 108.

[0073] Fig. 11C illustrates a piston 110, in accordance with one example of tiie present subject matter. The piston 110 indudes a rim 1110 at one mid 1112 and a groove 1114 below the rim 1110. The second end 1116 of toe piston 110 is to fit on a piston base 1106 on a support plate, such as the support plates 1102 and 1104. An O-ring may be disposed in the groove 1114 to form a seal between the piston assembly 108 and toe second hollow cylindrical part 306 on the body unit 102 with which the piston assembly is engaged. This helps in better creation of the suction force when toe piston assembly is released.

[0074] Fig. 12 illustrates components pi don assemblies, in accordance with an example implementation of the present subject matter. As shown, a piston 110 may fitted to each of the piston bases on toe support plates 1102 and 1104 and an O-ring, such as 1202-1, 1202-2, 1202-3,1202-4, may be disposed on each piston 110.

[0075] Fig. 13 illustrates the base cover 404 of toe air purge device 100, in accordance with an example implementation of the present subject matter. While toe base cover 404 is shown as two separate units 1302-1 and 1302-2 in one example, the base cover 404 may be formed as a single unit in other examples. The base cover 404 indudes dips 1304 to dip onto the body unit 102. Further, the base cover 404 indudes protrusions 1306 to fit in the extensions 1006 of the body unit 102 to avoid relative movement of the base cover 404 with respect to the body unit 102 on release of the piston assembly 108. [0076] Figs. 14 illustrates the actuator 114 of the air purge device 100, in accordance with an example implementation of the present subject matter. The actuator 114 may include a plurality of arms 1402-1 and 1402-2 extending laterally from the handle portion 406. The arms may include projections, for example, on a side surface, a bottom surface, or a top surface, to allow the actuator 114 to be held in place due to friction when coupled to the body unit 102 in the body assembly 208.

[007h The various components of the air purge device 100 may be assembled together using various methods, such as snap fit, dip on, press fit, friction fit fastening, and the like, as will be understood and is not described for brevity. Further, various grooves or other gripping surfaces may be provided, for example on the handle portion of the actuator, the manifold flap, and the body flap, to allow a user to grip or hold the components for purging air and installing the printheads.

[0078] The preceding description has been presented to illustrate and describe examples of the principles described. This description is not intended to be exhaustive. Many modifications and variations are possible in light of the above teaching.