FLUID EJECTION DEVICE ASSEMBLIES

In one example in accordance with the present disclosure, a fluid ejection device assembly is described. The fluid ejection device assembly includes a monolithically molded fluidic structure to extend between a separately molded body comprising a print fluid reservoir and a fluid ejection device. The fluidic structure includes a plenum to receive a print fluid from the body at a fluidic interface.

BACKGROUND

Printing devices may include a fluid ejection device assembly to contain and eject a print fluid (e.g., ink) onto a substrate. In some examples, the fluid ejection device assembly may be inserted into a printing device. Some examples of printing devices include an inkjet printer. In some examples, the fluid ejection device assembly may include a cartridge or pen device. In some examples, the fluid ejection device assembly may include a single print fluid (e.g., a single color of ink) in a single print fluid reservoir. In some examples, the fluid ejection device assembly may include multiple print fluids (e.g., multiple colors of ink) contained in separate print fluid reservoirs.

Typical printhead cartridges comprise a reservoir with capillary medium to hold ink, and a standpipe and plenum downstream of the medium, to deliver the ink to a printhead die. A flexible circuit comprises contact pads at the front side of the reservoir to connect to counter pads of the printer to receive print signals. The contact pads connect to flexible traces on the flexible circuit. The flexible circuit bends around the front/bottom edge along the bottom to bond its flexible traces to fluid ejection die bond pads at the die's head surface. Encapsulation may be applied to protect the bonds at the head surface.

DETAILED DESCRIPTION

In this specification, a fluid ejection device assembly may refer to a combination of components that are assembled to form a product comprising a fluid ejection device. The fluid ejection device may consist of a fluid ejection die or may comprise a fluid ejection die, for example embedded in and/or adhered to a molded compound, like a molded board, so that the fluid ejection device comprises both the molded support and fluid ejection die. The fluid ejection device is configured to eject fluid out of at least one nozzle, for example out of a relatively high-density nozzle array having a resolution of at least 600 dots per inch. The fluid ejection device assembly be a fluid ejection cartridge, sometimes referred to as an integrated printhead cartridge. In some approaches, a fluid ejection device assembly includes a body forming a reservoir that on the shelf and before a first use contains print fluid for printing when installed in a host printer. The reservoir includes capillary medium to hold the print fluid at an appropriate backpressure. The body comprises a head surface to which the fluid ejection device is attached. Either the molded support component is attached to the head surface, or the fluid ejection die is directly attached to the head surface. The head surface may also be referred to as head surface or headland or headland surface. The fluid ejection device is to be attached to that headland. In a use orientation, the headland is formed on a lower bottom wall of the body. For example, the reservoir body may be molded from a polymer (e.g., thermoplastic resin), whereby the headland is formed during the molding of the body. In some instances, the headland includes a recess to receive the fluid ejection device.

The fluid ejection cartridges comprise a reservoir with capillary medium to hold ink. A flexible circuit comprises contact pads at the front side of the body to connect to counter pads of the printer to receive print and/or data signals to control the fluid ejection device. The contact pads connect to flexible traces on the flexible circuit. The flexible circuit bends around the front/bottom edge of the body, over the headland, to bond the flexible traces to fluid ejection die bond pads.

As such, the circuitry that is used to control the fluid ejection die may be exposed to ink during printing, or even after printing, and/or wear from servicing of the fluid ejection die. Servicing may include wiping or capping or other forms of servicing. The circuitry may corrode due to the print fluid. The circuitry may be mechanically or chemically compromised because of the servicing.

Furthermore, forming the headland to receive the fluid ejection device sometimes is accompanied by relatively complex molding requirements and relatively high manufacturing costs, for example, depending on the design, size and complexity of the reservoir body. Sometimes, there is a desire to increase the efficiency of fluid and air (e.g., bubble) routing through the fluid ejection device assembly.

The present specification describes examples of a fluid ejection device assembly with a fluidic structure that is formed separate from the reservoir body. The fluidic structure comprises the headland that is to support the fluid ejection device. In some examples, after the body is formed (e.g., in a molding process) and the fluidic structure is formed (e.g., in a separate molding process), the fluidic structure is coupled to the body via a fluidic interface. Various components (e.g., a fluid ejection device, flexible circuit, etc.) may be connected to the fluidic structure.

In one example, the fluid ejection device assembly includes a monolithically molded fluidic structure to extend between, on the one hand, a separately molded body, comprising the print fluid reservoir, and, on the other hand, a separate fluid ejection device. The fluidic structure includes a plenum to receive a print fluid from the body at a fluidic interface. The fluid ejection device assembly may include a fluid ejection device sealingly attached to the fluidic structure. The fluid ejection device is to receive the print fluid from the plenum.

In another example, the present specification describes a fluid ejection device assembly that includes a monolithically molded body with a print fluid reservoir. The fluid ejection device assembly also includes a monolithically molded fluidic structure sealingly attached to the separately molded body. The fluidic structure includes a plenum to receive the print fluid at a fluidic interface with the body, and to deliver the print fluid to a separate downstream fluid ejection device. The fluidic structure also includes a headland against which to attach the fluid ejection device.

In yet another example, the present specification also describes a monolithically molded body to couple to a separately molded fluidic structure attached to a fluid ejection device. The example body includes a print fluid reservoir. The example body also includes a recess across a downstream bottom to support the separately molded fluidic structure. The example body further includes a standpipe between the reservoir and the recess. The standpipe opens into the recess to supply print fluid from the reservoir to the fluidic structure at a fluidic interface of the recess. The example body also includes two protrusions across the bottom, with the recess in between, so that, when attached, the fluidic structure extends between the protrusions.

In another example, the present specification also describes a fluid ejection device component. The example fluid ejection device component includes a fluidic structure with at least one channel to deliver fluid to a fluid ejection die and at least one via for passing electrical routing. The example fluid ejection device component also includes a fluid ejection die to receive the fluid from the fluidic structure. The example fluid ejection device component further includes an electrical connection support substrate. The example fluid ejection device component also includes electrical routing across the electrical connection support substrate extending through the via and connected to the fluid ejection die to control the fluid ejection die.

In yet another example, the present specification also describes a fluid ejection device component. The example fluid ejection device component includes a molded fluidic element for channeling fluid from a fluid reservoir to a fluid ejection die attached to a front headland of the fluidic element. The example fluid ejection device component also includes a fluid ejection die attached to a front headland surface of the fluidic element. The example fluid ejection device component further includes an electrical connection support substrate. The example fluid ejection device component also includes electrical routing on the electrical connection support substrate connected to the fluid ejection die at one end of the electrical connection support substrate and extending through a wall of the molded fluidic element to the headland for the connection to the fluid ejection die.

This disclosure addresses different components of a fluid device assembly, and also different combinations of such components that are to form the fluid device assembly. Different “unfinished,” also known as “intermediate,” components or assemblies, that do not yet provide for a final on-the-shelf product, may be derived from this disclosure. Certain components or assemblies derivable from this disclosure may provide for replacement parts to replace used parts in a product such as a print cartridge. In certain instances, the fluid ejection device assemblies and/or products, or even the separate components, addressed in, or derivable from, this disclosure may provide for a complete and final product.

Turning now to the figures,FIG.1illustrates an example of a fluid ejection device assembly100in a diagrammatic cross-sectional side view. In this example, the fluid ejection device assembly100includes a body102. The body102may form a print fluid reservoir104, which is a chamber to contain a print fluid106. In this example, the body102includes a single print fluid reservoir104. Other example bodies may be provided with a plurality of print fluid reservoirs. It should be noted thatFIG.1depicts the print fluid106with a flat top surface for ease of explanation. However, in some examples, the body102includes a capillary medium (e.g., a sponge or filter) to absorb and hold the print fluid106with a less straight line between full and empty space. The capillary force may be configured to hold the print fluid106against gravity while releasing the print fluid106when the fluid ejection device116ejects the print fluid106.

In some examples, the body102includes multiple print fluid reservoirs104that are to contain different print fluids106. For example, three print fluid reservoirs104of the body102each contain a unique color ink, for example cyan, magenta and yellow. In some examples, four print fluid reservoirs104include black, cyan, magenta and yellow. Thus, the fluid ejection device assembly100may implement multiple channels to print with different print fluids106. It should be noted that the examples described herein disclose a fluid ejection device assembly100for printing with a single print fluid106. However, the described principles may be expanded to implement a fluid ejection device assembly100for printing with multiple print fluids106and accordingly provided with a body containing multiple different print fluid reservoirs that hold respective print fluids.

In some examples, the body102is formed in a single molding. For example, the body102may be monolithically molded. As used herein, “monolithically molded” refers to an object that is molded as a single, discrete entity. In some examples, a monolithically molded object is formed in a single molding process using a single molded substance. In some examples, a monolithically molded object is formed in multiple molding processes (e.g., using a first shot mold, a second shot mold, etc.). The body102may be a single cast, injection molded, plastic shape formed from a molded substance such as a plastic or compound. For example, the body102may be formed from polyethylene, polyethylene terephthalate, or another suitable polymer material.

In some examples, the fluid ejection device assembly100includes a lid (not shown) on top of the body102to seal the print fluid reservoir104. In some examples, the lid includes a vent and a tear-off label sealing the vent. The body102may define a delivery system of the fluid ejection device assembly100that includes the print fluid reservoir104, a standpipe108to deliver print fluid106to the fluidic structure110, and other ink channel features. One complete print fluid delivery system may be provided for each color.

In some examples, the body102includes a number of side walls125and a bottom127. The side walls125and the bottom127may define a portion of the print fluid reservoir104. The side walls125and the bottom127may define a cavity to contain the print fluid106within the body102.

In some examples, the body102may connect to the fluidic structure110at a fluidic interface112through the standpipe108. The standpipe108may be provided downstream of the reservoir104. The standpipe108may comprise a shaft that fluidically connects the reservoir104and the fluidic structure110. The standpipe108may include a downstream opening, formed in the bottom127of the body102. In some examples, the standpipe108supplies print fluid106from the reservoir104to the downstream fluidic structure110. The standpipe108may connect the reservoir104to a downstream plenum114.

The fluid ejection device assembly100may include a fluidic structure110that is formed separate from the body102. The body102may be molded separate from the fluidic structure110. In some examples, the monolithically molded fluidic structure110extends between (i) a separately molded body102comprising the print fluid reservoir104and (ii) a fluid ejection device116comprising a fluid ejection die, the reservoir104and fluid ejection device116respectively upstream and downstream of the fluidic structure110.

In some examples, the fluidic structure110is formed from the same material (e.g., polymer) as the body102. In some examples, the fluidic structure110is formed from a different material (e.g., a second polymer) than the body102. For instance, a resin used to mold the fluidic structure110may be selected for performance criteria that differ from the body102. In other words, the material selected to form the fluidic structure110and body102may be optimized for the respective applications.

The fluidic structure110includes a plenum114to receive the print fluid106from the body102. The plenum114may extend from the fluidic structure110. The plenum114may receive the print fluid106at the fluidic interface112with the standpipe108of the body102. The plenum114may deliver the print fluid106to the fluid ejection device116. The plenum114is defined by a cavity in the fluidic structure110that channels print fluid106from the standpipe108to a feed slot of the fluid ejection device116. The plenum114may include a first opening111at the fluidic interface112with the body102, whereby the edges that define the first opening111are sealingly attached (e.g., adhered or welded) to the downstream edges of the standpipe108.

The monolithically molded fluidic structure110may be sealingly attached to the separately molded body102. The standpipe108of the body102may connect to a plenum114of the fluidic structure110at the fluidic interface112. The plenum114may be adhered to the standpipe108at the fluidic interface112using an adhesive. In some examples, the standpipe108and/or fluidic structure110include flanges, projections, or other structures to which the plenum114is attached to the standpipe108(e.g., via an adhesive, welding, mechanical fastener, etc.). The fluidic interface112may allow the print fluid106to exit out of the standpipe108and into the plenum114of the fluidic structure110. The fluidic interface112may also permit air (e.g., bubbles) entering the fluidic structure110to pass into the print fluid reservoir104. Sometimes air enters the fluidic structure110through nozzles of the fluid ejection device116. The air may then be vented out of the body102(e.g., via a vent in the lid).

The volume of the plenum114is defined by inner walls of the fluidic structure110. The plenum114may comprise two ramped top walls119that diverge downwards and outwards away from the standpipe108, and two side walls parallel to a slot-shaped second opening (e.g., see reference number438ofFIG.4A) and/or parallel to a longitudinal nozzle array direction of the fluid ejection device116. Hence, the plenum114channels the print fluid from the first to the second opening. In one example, the second opening (438ofFIG.4A) extends through the headland of the fluidic structure110that receives the fluid ejection device116. The top walls of the plenum114widen the volume of the plenum114in the downstream direction to provide the print fluid received from the standpipe108over the length of the second opening and the fluid ejection device116to replenish all nozzles. A separate feed slot of the fluid ejection device116may be a trench that supplies the print fluid106to nozzles of the fluid ejection device116. In one example, the fluid ejection device comprises a molded carrier (also referred to as molded component or support elsewhere in this disclosure) and the feed slot is a molded slot that provides the print fluid to fluid feed holes in a fluid ejection die that is embedded in the molded carrier, whereby the feed holes connect to ejection chambers and nozzles.

In some examples, the fluid ejection device116includes a fluid ejection die with number of nozzles to eject the print fluid106received from the plenum114. The fluid ejection device116may also include a number of electrical bond pads to receive control signals for fluid ejection and/or data reading and writing. A printing device may provide control signals to the fluid ejection device116to control which nozzles fire. The fluid ejection device116may include a silicon-based microelectromechanical systems (MEMS) device with a number of nozzles. The electrical bond pads of the fluid ejection device116may be aligned along the long axis of the fluid ejection device116.

In some examples, the fluid ejection device116is a precision overmold (POM) device comprised of a molded component and a fluid ejection die attached to the molded component (also referred to as molded “carrier” elsewhere in this disclosure). In one example, the molded component is a molded board that embeds and/or supports a relatively thin fluid ejection die. The molded component may provide rigidity to the fluid ejection device116and/or provide for an intermediate fluid channel. The molded component of the POM device may receive the print fluid106from the fluidic structure110and may provide the print fluid106to the fluid ejection die. In some examples, the molded component includes a fluid slot to receive the print fluid106from the plenum114. The fluid ejection die may be attached to (e.g., embedded in) the molded component (e.g., during over-molding of the molded component). The fluid ejection die may receive the print fluid106through the fluid slot. In other examples the fluid ejection device is in itself (i.e., consists of) a fluid ejection die that directly receives the fluid from the second opening (438,FIG.4A).

In some examples, the fluid ejection device116is coupled to the fluidic structure110. The fluid ejection device116may be sealingly attached to the fluidic structure110with an adhesive at a second fluidic interface (e.g., see reference number329ofFIG.3). In some examples, the fluidic structure110includes a headland115to receive the fluid ejection device116(e.g., fluid ejection die). The headland115may be a front surface of the fluidic structure110that interfaces with the fluid ejection device116. The headland115may include a recess (e.g., see reference number432ofFIG.4A) to receive the fluid ejection device116, and a plurality of standoffs to position the fluid ejection die within the recess.

The fluid ejection device116may receive the print fluid106from the plenum114. A fluid-tight seal may be created between the fluidic structure110and the fluid ejection device116. As said, the fluidic structure110may include the recess (432,FIG.4A) to receive the fluid ejection device116. The recess (432,FIG.4A) may house and protect the fluid ejection device116. Thus, a front surface of the fluid ejection device116may be exposed while the sides and a back surface of the fluid ejection device116may be covered and/or surrounded by the surfaces of the fluidic structure110forming the recess (432,FIG.4A). The second slot-shaped opening (438,FIG.4A) of the plenum114is formed in the recess (432,FIG.4A) of the fluidic structure110to provide print fluid106to the fluid ejection device116.

Because the fluidic structure110is formed separate from the body102, the fluidic structure110may be defined by a headland115(e.g., a front surface) and a back117. The headland115may include the recess (432,FIG.4A) for receiving the fluid ejection device116. The back117may be the external back of the structure110, opposite to the head surface, that faces the reservoir104, which may include the external sides of the ramped top walls of the plenum114and the top side of the flange that defines the headland (seeFIG.4A). As can be appreciated fromFIG.4B, the back117may be partially defined by a flanged wall that, in use, is not in contact with the print fluid. The plenum walls themselves are in contact with the print fluid. In some examples, the headland115includes the recess in which the fluid ejection device116attaches. Thus, the head surface may face the print substrate during printing by the fluid ejection device assembly100. The headland115may form a continuous and/or flush surface surrounding the fluid ejection device116. Thus, the fluidic structure headland115is free of projections around the fluid ejection die.

The bottom surface of the fluidic structure110may interface with a printing device seal (not shown) that covers the nozzles of the fluid ejection device116before usage, during storage or transport. For example, the printing device seal is a separate device of the printing device that engages the continuous sealing surface when the fluid ejection device assembly100is not in use. The continuous sealing surface may be a homogenous (i.e., continuous) surface that is relatively flat to provide a hermetic seal.

In an installed configuration, the back117of the fluidic structure110may be positioned to face the bottom127of the body102. In some examples, the bottom127of the body102includes a recess (e.g., see reference number224ofFIG.2) and protrusions (e.g., see reference number229ofFIG.2) projecting on each side of the recess (224,FIG.2). The fluidic structure110may be positioned within the recess (224,FIG.2). Since the fluidic structure110comprises a ramped ceiling (i.e., a partially ramped back117), a gap123may be formed between the back117of the fluidic structure110and the bottom127of the body102when the fluidic structure110is coupled to the body102in an installed configuration.

In some examples, the fluid ejection device assembly100also includes a flexible circuit118electrically coupled to the fluid ejection device116. The flexible circuit118may provide for an electrical interface between the fluid ejection device116and the printing device. The electrical interface may include electrical interface pads to interface with a printing device, for example at a front of the fluid ejection device assembly100. The flexible circuit118may include a fluidic structure portion with bond pads to couple to bond pads of the fluid ejection device116, for example at a bottom127of the body102. The flexible circuit118may also include wire traces to couple the pads in the electrical interface to the bond pads in the fluidic structure portion. The flexible circuit may comprise a generally flat substrate with relatively flat electrical routings to connect the electrical interface pads with the die-side bond pads. Some examples are relatively flexible in that they permit a curve of the substrate, in this example to bend from a relatively vertical front to a relatively horizontal bottom. In other examples, the flexible circuit may comprise rigid portions or instead another electrical connection support substrate may be used that may be thin yet relatively rigid and that may still connect the opposite end pads. Also the electrical routing between the end pads may be supported by multiple substrates.

In some examples, to electrically connect to the bond pads, the flexible circuit118extends between the back of the fluidic structure110and the bottom127of the body102. The flexible circuit118may be mechanically coupled to the back of the fluidic structure110. The flexible circuit118may be attached (e.g., via an adhesive, weld, fastener, etc.) to the back of the fluidic structure110. Because the flexible circuit118may extend along (e.g., be coupled to) the back of the fluidic structure110, the continuous sealing surface on the headland115of the fluidic structure110can be left clear to interface with a seal or service component. Furthermore, attaching the flexible circuit118to the back of the fluidic structure110may remove the flexible circuit118from the corrosive environment of the headland115of the fluidic structure110due to the presence of the print fluid106at the headland115. The flexible circuit118may be mechanically attached (e.g., via an adhesive) to the back of the fluidic structure110. A protective material (e.g., a coverlay) covering the flexible circuit118may provide a continuous capping surface for a printing device seal.

In some examples, a first portion (e.g., the fluidic structure portion) of the flexible circuit118connects to the back of the fluidic structure110and a second portion (e.g., the electrical interface) of the flexible circuit118may connect to a front of the body102. In other examples, the flexible circuit118does not attach to the body102. For example, the electrical interface of the flexible circuit118may extend out from the fluidic structure110without attaching to the body102.

The described examples may provide greater efficiency for manufacturing the fluid ejection device assembly100. For example, the fluid ejection device116and flexible circuit118may be placed in the fluidic structure110when separated from the body102. Then, the fluidic structure110may be attached to the body102and the flexible circuit118may be wrapped and attached to the body102to complete the fluid ejection device assembly100. Thus, manufacturing processes may be separated such that the fluidic structure110and body102are formed separately.

By separating the fluidic structure110from the body102, the molding of the body102may be simplified. In some examples, more complex and efficient fluid and air routing geometry is formed on the body102and the fluidic structure110as compared to an approach that forms the fluidic structure with the body. In some examples, a new body filled with new print fluid can be attached to a used and/or recycled fluidic structure110with the fluid ejection device, whereby the flexible circuit118may be either re-used as well or be new for first use or both.

As discussed above, different materials may be used to form the body102and the fluidic structure110. Thus, material (e.g., resin) choices may be optimized for the respective applications of the body102and the fluidic structure110. Furthermore, reliability of the fluid ejection device assembly100may be increased by removing the flexible circuit118from the capping space where a high amount of print fluid106accumulates.

In some examples, by separating the fluidic structure110molding from the body102molding, the fluidic structure110dimensional tolerances are enhanced. For example, the region of the fluidic structure110that houses the fluid ejection device116may be flatter that may be achieved with a single molding of the body102and fluidic structure110. Furthermore, by molding the fluidic structure110separate from the body102, a different material may be used for the fluidic structure110than for the body102, which may provide enhanced dimensional tolerances than the material used of the body102.

FIG.2illustrates a perspective view of the fluid ejection device assembly100, according to an example. In the view ofFIG.2, the fluid ejection device assembly100is oriented such that the fluidic structure110is facing upward. It should be noted that in an installed orientation in a printing device, the fluidic structure110may be located at the bottom of the fluid ejection device assembly100. A lid220may be located at a top opening of the body102.

As described above, the body102may be formed (e.g., molded) separately from the fluidic structure110. The fluidic structure110may then be attached to the body102. In some examples, the body102includes a recess224to support and/or contain the fluidic structure110. The fluidic structure recess224may be formed in the bottom127of the body102, whereby the bottom127is defined by said recess224and a projecting bottom body protrusion229on each side of the recess224. The recess224and bottom protrusions229extend in a longitudinal direction of the body102(from a front226to a back of the body102), parallel to each other, for example across the entire bottom127. Thus, the recess224extends across the bottom127of the body102, from a front up to a back wall of the body102. The recess224provides for a cavity for a flexible circuit118extending partly along the front of the body102to attach to a fluid ejection die (e.g., fluid ejection device116) through a back side of the fluidic structure110.

In use, the protrusions229may form pockets in the reservoir104that contain print fluid, for example free flowing print fluid under the capillary material in the main reservoir space above the pockets. The free print fluid in these pockets may be absorbed by the capillary material in the reservoir104as the print fluid is extracted from the capillary material whereby the print fluid in the pockets may be replaced by air. In other examples the protrusions229may comprise air and/or capillary material in addition to or instead of the print fluid. The protrusions229may extend next to and on each side of the standpipe108and/or fluidic structure110so that the print fluid may flow upwards from a respective protrusion229into the capillary material and then down again into the standpipe108and plenum114. The plenum114extends between the protrusions229.

The body102may include a standpipe for delivering the print fluid from the reservoir104to the plenum114. The standpipe108may open in the recess224in the bottom127to fluidically interface with the plenum114. The fluidic structure110may be positioned in the fluidic structure recess224and attached to the body102(e.g., via an adhesive).

In some examples, the fluidic structure recess224forms a cavity for the flexible circuit118to attach to a back of the fluidic structure110opposite the fluid ejection device116. In this example, the fluid ejection device116is coupled to the headland115of the fluidic structure110. The flexible circuit118may be coupled to the back of the fluidic structure110such that a fluidic structure portion of the flexible circuit118is located between the bottom127of the body102and the back of the fluidic structure110. An electrical interface of the flexible circuit118may be bent and attached to a front226of the body102. The flexible circuit118may be electrically coupled to the fluid ejection device116located on the headland115of the fluidic structure110, as also illustrated inFIG.3.

FIG.3illustrates a cross-sectional side view detail of a fluid ejection device assembly100, according to an example. In this example, the fluidic structure110is molded separately from the body102. The body102includes a standpipe108formed on the bottom127.

The fluidic structure110includes a plenum114extending from the back of the fluidic structure110. The plenum114is to couple with standpipe108of the body102at the fluidic interface112. In this example, the body102is coupled to the plenum114with an adhesive328located between the standpipe108and the plenum114at the fluidic interface112.

In some examples, the fluidic structure110includes a second fluid interface329to couple the fluid ejection device116to the fluidic structure110. The fluidic structure110may include an opening to allow print fluid106to pass into the fluid ejection device116. The fluid ejection device116may be attached to the second fluid interface329with an adhesive to create a fluid-tight seal around the perimeter of the fluid ejection device116. Thus, the print fluid106may be provided to the nozzles of the fluid ejection device116without leaking out of the second fluid interface329.

FIG.4Aillustrates a perspective view of the fluidic structure110, according to an example. InFIG.4A, a headland115of the fluidic structure110is visible. In this example, a fluid ejection device recess432is formed in the headland115of the fluidic structure110to house the fluid ejection device (not shown). A longitudinal fluid ejection device opening438may be formed in the fluid ejection device recess432. In some examples, the fluid ejection device opening438is a slot through which print fluid may flow into the fluid ejection device to replenish the nozzles.

The headland may be a surface of the fluidic structure110to receive the fluid ejection device. In the illustrated example, the molded longitudinal recess432receives the fluid ejection die whereby the headland is defined by that recess432. The recess432may be open and connected to a via434at each longitudinal end of the recess432and at the opposite longitudinal ends of the fluid ejection die when positioned, to facilitate electrical bonding to the fluid ejection die without projecting electrical bonds or wiring beyond the die surface. Each via434a,434bis an opening in the headland that may be part of the longitudinal recess, for example molded together with the longitudinal recess432. The via passes through the flanged wall of the fluidic structure110, from the back117to the headland115. The fluidic structure recess432integrally includes the vias (e.g.,FIG.4,434a-b), forming a continuous (e.g., molded) opening in the headland115, with one via at each end of the recess432, at the opposite longitudinal ends of the fluid ejection device116. Electrical connections may be formed between the bond pads of the flexible circuit118and the bond pads of the fluid ejection device116extending through and/or in the vias. In another example, one via is provided at a single end of the recess432.

In some examples, a plurality of standoffs436a-care formed within the fluid ejection device recess432to position the fluid ejection device (e.g., fluid ejection die) within the fluid ejection device recess432. In this example, the fluidic structure110includes three standoffs436a-cfor the fluid ejection device to sit on. The three standoffs436a-cmay be tightly toleranced for flatness to form a horizontal plane for the fluid ejection device.

In some examples, the fluidic structure110holds (i.e., supports) the fluid ejection device. An adhesive applied within the fluid ejection device recess432may secure the fluid ejection device and may maintain a fluid-tight channel between the print fluid reservoir in the body of the fluid ejection device assembly and the nozzles of the fluid ejection device.

The vias434a-bmay be openings from the headland115to a back117of the fluidic structure110. When the flexible circuit and the fluid ejection device are attached to the fluidic structure110, the vias434a-bmay expose bond pads of the flexible circuit to facilitate electrical connections to bond pads of the fluid ejection device. Thus, electrical connections may be formed between the bond pads of the flexible circuit and the bond pads of the fluid ejection device through the multiple vias434a-bof the fluidic structure110.

FIG.4Billustrates another perspective view of the fluidic structure110, according to an example. InFIG.4B, a back117of the fluidic structure110is visible. In this example, the plenum114extends from the back117of the fluidic structure110, basically protruding to the back from the flange like wall that forms the headland, to channel the print fluid from the body102to the fluid ejection die, whereas the flange like wall may provide for the vias and also for surface to which the flexible circuit118may be attached, without contacting print fluid. The plenum114may receive a print fluid from the body of the fluid ejection device assembly. The plenum114may facilitate the flow of the print fluid to the fluid ejection device opening438.

A fluidic interface112may be formed at an upstream opening111of the plenum114. In this example, the fluidic interface112includes a surface surrounding the opening111to the plenum114. An adhesive may be used to connect the second fluidic interface112to the body of the fluid ejection device assembly.

FIG.4Cillustrates a view of the headland115of the fluidic structure110, according to an example. As described above, a fluid ejection device recess432may be formed in the headland115. A continuous sealing surface442(represented in dashed lines inFIG.4C) on the headland115surrounding the fluid ejection device recess432may interface with a printing device seal (not shown). Thus, in this example, the fluidic structure110provides a surface for the printing device seal to cap the nozzles of the fluid ejection device.

FIG.5Aillustrates a view of the flexible circuit118, according to an example. The flexible circuit118(also referred to as a flex circuit) may include electronic circuits mounted on a flexible substrate (referred to herein as an electrical connection support substrate). In some examples, the electrical connection support substrate includes a flexible polymer (e.g., polyimide, polyester, etc.). As said, in other examples, at least one substrate may be used that is not entirely flexible. Thus, as used herein, the electrical connection support substrate may include the flexible circuit118, or, for example, another relatively thin substrate to support electrical routings. In other examples, an electrical connection support substrate may not need to bend from a front226wall of the reservoir104around the bottom127of the reservoir104to the fluidic structure110but the electrical connection support substrate may remain relatively straight and flat, for example with printer contacts in the same plane as the ejection die bond pads556. In certain examples the electrical connection support substrate comprises multiple layers with electrical routings between layers. In a certain sense, the electrical routings may extend “on” or “in” the substrate and routings “on” the substrate should be interpreted as also including “in”.

In some examples, the flexible circuit118includes an electrical interface550. The electrical interface550may be a portion of the flexible circuit118that includes contact pads552to form an electrical connection with a host printing device. In some examples, the pads552of the electrical interface550communicate with a dimple flex of the printing device.

The flexible circuit118may include a fluidic structure portion554. In some examples, the fluidic structure portion554includes bond pads556to couple to the fluid ejection device. In some examples, wire traces558electrically couple the pads552in the electrical interface550to the bond pads556in the fluidic structure portion554. The flexible circuit118may comprise electrical routings that connect the printer contact pads552on one end with the bond pads556for a fluid ejection die at the other end. The electrical routings and the bond pads556may be grouped so that they connect to corresponding pads of a fluid ejection die at each longitudinal end of a fluid ejection die. In the illustration two separate groups of bond pads556are illustrated, to connect to each end of a longitudinally shaped fluid ejection die.

FIG.5Billustrates another view of the flexible circuit118, according to an example. In this example, the flexible circuit118as illustrated inFIG.5Amay be implemented with a protective material560. The protective material560covers a portion of the wire traces558. This protective material560may be referred to as a coverlay. In some examples, the protective material includes a flexible polymer (e.g., polyimide) that is bonded to the flexible circuit118. The protective material560may expose the pads552in the electrical interface550and the bond pads556in the fluidic structure portion554.

FIG.6illustrates a fluid ejection device component601, according to an example. In some examples, the fluid ejection device component601includes a flexible circuit118attached to a fluidic structure110. In this example, the fluidic structure portion of the flexible circuit118is located on the back117of the fluidic structure110. In some examples, a portion of the flexible circuit118is attached to the back117side of the fluidic structure110with an adhesive. Thus, the electrical routing may extend along the back117side of the fluidic structure110. The electrical interface portion of the flexible circuit118may extend out from the fluidic structure110. Because the flexible circuit118is located on the back117of the fluidic structure110, the continuous sealing surface (e.g.,FIG.4C,442) may be kept clear to interface with the printing device seal.

In some examples, the fluid ejection device component601includes a rigid molded component to support the fluid ejection die. The rigid molded component and the fluid ejection die may form the fluid ejection device116. The rigid molded component is attached to the front headland115of the fluidic structure110. The electrical routing from the flexible circuit118may extend along the rigid molded component (e.g., through a via).

In some examples, the fluid ejection device component601includes at least one molded fluidic element for channeling fluid106from a fluid reservoir104to a fluid ejection die attached to the front headland115of the fluidic element. The fluidic element may include a molded component in which the fluid ejection die is at least partially embedded and fluidic structure110with the plenum114to receive fluid106from the reservoir104and deliver the fluid to the fluid ejection die. The molded component includes a channel for the fluid106to flow from the plenum114to the fluid ejection die.

In some examples, the fluid ejection device component601includes a fluid ejection die attached to the front headland115surface of the fluidic element. As described above, the fluid ejection die may be a component of the fluid ejection device116described herein.

In some examples, the fluid ejection device component601includes an electrical connection support substrate (e.g., the flexible circuit118) and electrical routing on the electrical connection support substrate connected to the fluid ejection die at one end of the electrical connection support substrate and extending through a wall of the molded fluidic element to the headland115for the connection to the fluid ejection die. The wall may include a via434at one or each end of the fluid ejection die through which the electrical routing extends from the back117side to a front side (e.g., headland115) of the wall. A wall portion in which the via434is positioned is not a wall portion that defines a fluid channel. The via434may include an opening in the fluidic element from the headland surface115to the back117side of the fluidic element (e.g., fluidic structure110).

FIG.7Aillustrates electrical connections760a-bbetween the flexible circuit118and the fluid ejection device116, according to an example. In some examples, the fluid ejection device116(including a fluid ejection die) is located on the headland115of the fluidic structure110. For example, the headland115may include a molded longitudinal recess432to receive the fluid ejection device116. A first set of electrical connections760abetween the flexible circuit118and the fluid ejection device116may be made through a first via434aof the fluidic structure110. A second set of electrical connections760bbetween the flexible circuit118and the fluid ejection device116may be made through a second via434bof the fluidic structure110. In some examples, the electrical connections760a-binclude wirebonding between the bond pads of the flexible circuit118and bond pads of the fluid ejection device116. An example of a wirebonding approach is described inFIG.8.

FIG.7Billustrates encapsulant covers762a-bto protect the electrical connections760a-bbetween the flexible circuit118and the fluid ejection device116, according to an example. In this example, a protective material forms encapsulant covers762a-bover the electrical connections760a-b.In some examples, the encapsulant covers762a-bare formed from an adhesive, resin, or other substance that fills the via434a-band encapsulates the electrical connections760a-bbetween the flexible circuit118and the fluid ejection device116. The encapsulant covers762a-bmay protect and preserve the electrical connections760a-bbetween the flexible circuit118and the fluid ejection device116.

FIG.8illustrates wirebonds882between the flexible circuit118and the fluid ejection device116, according to an example. In this case, a wirebond882may be formed between a bond pad556of the flexible circuit118and a bond pad880of the fluid ejection device116. The wirebond882may pass through the via434aof the fluidic structure110. As described above, the via434aof the fluidic structure110may expose the bond pads556of the flexible circuit118below so that the bond pads556can be wirebonded to the bond pad880of the fluid ejection device116. In some examples, the vias of the fluidic structure110are formed to provide clearance to the wirebond882. A minimum clearance between the walls of the via434aand the wirebond882may be provided. Thus, the electrical routing includes a plurality of wirebonds882passing through the via434ato connect a plurality of bond pads556on the electrical connection support substrate (e.g., flexible circuit118) to a plurality of bond pads880on the fluid ejection die (e.g., fluid ejection device116)

FIG.9illustrates an example of a fluidic structure110in a cross-sectional side view. The fluidic structure110may be a component of a fluid ejection device assembly that is formed separate from the body housing the print fluid reservoir. The body may be molded separate from the fluidic structure110. In some examples, the fluidic structure110are formed from a molded compound (e.g., polymer).

In some examples, the structure110is a fluidic structure to extend between a separately molded print fluid reservoir and a fluid ejection device116. In some examples, the fluid ejection device116includes a fluid ejection die with number of nozzles to eject the print fluid received from the plenum114. The fluid ejection device116may also include a number of electrical bond pads to receive control signals. A printing device may provide control signals to the fluid ejection device116to control which nozzles fire. In some examples, the fluid ejection device116is a silicon-based microelectromechanical systems (MEMS) device with a number of nozzles. The electrical bond pads of the fluid ejection device116may be aligned along the long axis of the fluid ejection device116.

In some examples, the fluid ejection device116includes at least one embedded fluid ejection die in a molded compound carrier. For example, the fluid ejection device116may be a precision overmold (POM) device with a molded component attached to a fluid ejection die. The molded component of the POM device may receive the print fluid from the fluidic structure110and may provide the print fluid to the fluid ejection die. In some examples, the molded component includes a fluid slot to receive the print fluid from the plenum114. The fluid ejection die may be attached to the molded component (e.g., during over-molding of the molded component). The fluid ejection die may receive the print fluid through the fluid slot.

The fluid ejection device116may attach to the fluidic structure110. In some examples, the fluidic structure110is molded separately from the print fluid reservoir. In some examples, the fluidic structure110is a monolithically molded object. As used herein, “monolithically molded” refers to an object that is molded as a single, discrete entity. In some examples, a monolithically molded object is formed in a single molding process using a single molded substance. In some examples, a monolithically molded object is formed in multiple molding processes (e.g., using a first shot mold, a second shot mold, etc.) to form a single, discrete entity.

In some examples, the fluidic structure110includes a plenum114. The plenum114may receive a print fluid (e.g., from the print fluid reservoir). The plenum114may direct the received print fluid to the second opening438of the headland115, which provides the print fluid to the fluid ejection device116.

In some examples, the plenum114includes a first opening111to interface with, and receive print fluid from, the print fluid reservoir. For example, a print fluid from the print fluid reservoir enters the plenum114of the fluidic structure110through the first opening111. The first opening111may be located on a back117of the fluidic structure110when the fluidic structure110is in an installed orientation in a printing device.

In some examples, the first opening111has a primarily rectangular shape. In some examples, the corners of the first opening111are rounded to facilitate fluid and air transfer. In some examples, the first opening111has other shapes (e.g., circular, oval, capsule, square, etc.).

The fluidic structure110includes a headland115. In some examples, the headland115is a portion of the fluidic structure110that includes at least one second opening438. The headland115receives the fluid ejection device116for delivering print fluid to the fluid ejection device116through the second opening438. The fluid ejection device116may be attached to the headland115with an adhesive.

The plenum114may connect to the second opening438. In some examples, the plenum114is defined (e.g., formed) by a ceiling and a floor. In some examples, the plenum114includes a first wall and a second wall. A relatively large plenum ceiling height (e.g., as compared to the size of the fluid ejection device116) may allow for ample print fluid flow to the fluid ejection device116. The plenum ceiling height may also provide room for bubbles to escape the plenum114and exit out of the first opening111into the print fluid reservoir. In some examples, the plenum114includes opposite walls along a longitudinal direction of the plenum114, and along a length of the second opening438. The second opening438may have a longitudinal shape, whereby the grooves908extend on at least one of those side walls of the plenum114perpendicular to the second opening438. An example of the walls of the plenum114is described inFIGS.4A-4C.

In some examples, the plenum114includes grooves908extending between the first opening111into the plenum114. The grooves908may extend longitudinally between the first opening111and the second opening438. In some examples, the grooves908of the plenum114form a grooved standpipe. In some examples, the grooves908are formed in a wall of the plenum114. In some examples, the grooves908extend into the wall of the plenum114adjacent the first opening111. The grooves908may start at or near the first opening111and may extend into the wall of the plenum114.

In some examples, the grooves908include at least three grooves. In some examples, a first set of grooves908is formed on a first wall of the plenum114and a second set of grooves908is formed on a second wall of the plenum114. In some examples, the height of the grooves908is more than half of the height of the plenum114.

In some examples, the grooves908are sized to restrict bubbles in a print fluid contained within the plenum114from entering the grooves908. For example, bubbles may enter the plenum114through nozzles in the fluid ejection device116. If these bubbles remain within the plenum114, the bubbles may block the flow of print fluid through the plenum114. The grooves908may prevent bubbles in the print fluid from adhering to the second opening438. The grooves908may form a fluidic pathway for the print fluid to pass through the first opening111of the plenum114downstream to the fluid ejection device116. The grooves908may be sized to prevent bubbles in the plenum114from entering the grooves908and blocking the flow of print fluid.

In some examples, the fluidic structure110is adhered to the reservoir using an adhesive bond. The grooves908may be configured to prevent bubbles in the print fluid from adhering to the adhesive bond. The grooves908may extend into at least one side wall of the plenum114from a point adjacent the adhesive bond up to a point adjacent the second opening438, to trap bubbles and form a fluidic pathway for the print fluid. The grooves908may position the bubbles away from the adhesive bond.

FIG.10illustrates a body102for a fluid ejection device assembly in a perspective view, according to an example. The body102may be a monolithically molded body to couple to a separately molded fluidic structure (not shown) attached to a fluid ejection device (not shown). The body102includes a print fluid reservoir104, which is a chamber to contain a print fluid. The body102also includes a recess224at a downstream bottom127to support the separately molded fluidic structure. The body102includes a standpipe108between the reservoir104and the recess224. The standpipe108opens into the recess224to supply print fluid from the reservoir104to the fluidic structure at a fluidic interface112of the recess224. In some examples, the recess224extends across the bottom127of the body102and provides for a cavity for a flexible circuit (not shown) to attach to a back of the fluidic structure opposite the fluid ejection device.