Patent Publication Number: US-2023137179-A1

Title: Electrically conductive structures

Description:
BACKGROUND 
     Some types of printing utilize liquid. For example, some types of printing extrude liquid onto media or material to produce a printed product (e.g., two-dimensional (2D) printed content, three-dimensional (3D) printed objects). In some examples, a printhead may be utilized to extrude ink onto paper to print text and/or images. In some examples, a printhead may be utilized to extrude fusing agent onto powder in order to form a 3D printed object. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a diagram illustrating a perspective view of an example of a fluid reservoir; 
         FIG.  2    is a diagram illustrating examples of a graphite-loaded plastic pins; 
         FIG.  3    is a diagram illustrating an exploded view of an example of a print cartridge; 
         FIG.  4    is a flow diagram illustrating one example of a method for manufacturing a fluid reservoir; 
         FIG.  5 A  is a diagram illustrating a perspective view of an example of a fluid reservoir well; and 
         FIG.  5 B  is a diagram illustrating a cross-sectional view of an example of the conductive non-metal structure described in relation to  FIG.  5 A . 
     
    
    
     DETAILED DESCRIPTION 
     Some issues arise in the context of storing and/or utilizing fluids. A fluid is a liquid substance. In some examples, a fluid may damage (e.g., corrode, etch, etc.) a material or materials in contact with the fluid. For instance, electrochemical reactions may occur at an interface between fluid and material. In some examples, the electrochemical reactions may cause etching, where some or all of the material may move into the fluid. 
     An open circuit potential is a naturally occurring voltage that may occur due to electrochemical reactions at an interface between fluid and material (e.g., solid material). In some examples, the material may be silicon or may include silicon (e.g., silicon-based circuitry). In some examples, electrochemical reactions may cause etching of silicon into fluid that is in contact with the silicon. 
     In some examples, a voltage may be applied to the material (e.g., silicon). For instance, if a positive voltage is applied to silicon, the etching may increase. A high enough voltage may promote passivation (e.g., oxidation of the silicon surface). In some examples, a passivated surface may etch more slowly than a plain surface. For instance, a passivated silicon surface may etch more slowly than a plain silicon surface. 
     Some examples of the techniques described herein may reduce, mitigate, and/or neutralize the open circuit potential in order to reduce, mitigate, and/or neutralize etching at an interface between a fluid and a material. For instance, a conductive material may be electrically connected to a material (e.g., silicon). The conductive material may form a galvanic couple with the material, which may change the open circuit potential (e.g., between fluid and silicon). In some examples, the changed open circuit potential may be high enough to place the material into a passivation range, without applying an external bias. 
     In some examples, the foregoing issues may arise in the context of fluid reservoirs. A fluid reservoir is a container for fluid. Examples of fluid reservoirs include print liquid containers, print cartridges, print liquid supplies, etc. Print liquid is a fluid for printing. Examples of print liquid include ink and fusing agent. In some examples, a material that is prone to etching in print liquid may be exposed to the print liquid. For example, silicon circuitry (e.g., silicon printhead circuitry and/or other circuitry) may be in contact with the print liquid. Etching of the silicon circuitry may occur, which may cause circuitry failure and/or contamination of the print liquid. Accordingly, it may be beneficial to reduce, mitigate, and/or neutralize etching of a material in contact with a fluid. 
     In some examples, fluid reservoirs (e.g., print cartridges) may be constructed of thermoplastics. Thermoplastics may be injection molded and may be compatible with high volume manufacturing and/or assembly methods. It may be beneficial for the construction materials (e.g., materials to construct components of fluid reservoirs) to be compatible with print liquid and/or to be robust to environmental conditions over the life of the fluid reservoir. In some examples, fluid reservoirs may be constructed from thermoplastics such as polypropylene (PP), low-density polyethylene (LDPE), high-density polyethylene (HDPE), polyethylene terephthalate (PET), polycarbonate (PC), and/or blends thereof (e.g., copolymers such as a polypropylene-polyethylene blend). Some thermoplastics may be compatible with high volume assembly methods such as injection molding and/or welding. Welding is an action where materials fuse together. For example, welding may form bonds (e.g., molecular bonds) between materials. In some examples, welding materials may include a phase change of (e.g., melting and/or liquifying), intermingling, and/or mixing the materials. In some examples, welding may be capable of creating waterproof seals to contain the print liquid. In some examples, welding may occur without another bonding agent, additional part, adhesive, and/or sealant. 
     Throughout the drawings, identical reference numbers may designate similar, but not necessarily identical, elements. Similar numbers may indicate similar elements. When an element is referred to without a reference number, this may refer to the element generally, without necessary limitation to any particular figure. The figures are not necessarily to scale, and the size of some parts may be exaggerated to more clearly illustrate the example shown. Moreover, the drawings provide examples and/or implementations in accordance with the description; however, the description is not limited to the examples and/or implementations provided in the drawings. 
       FIG.  1    is a diagram illustrating a perspective view of an example of a fluid reservoir  100 . Examples of the fluid reservoir  100  include print liquid supplies, print liquid containers, print cartridges, etc. The fluid reservoir  100  may contain and/or transfer fluid  102  (e.g., print liquid, ink, agent, etc.). In some examples, the fluid reservoir  100  may be designed to interface with a host device. A host device is a device that uses and/or applies fluid  102 . Examples of a host device include printers, ink jet printers, 3D printers, etc. In some examples, it may be beneficial to replenish or replace the fluid reservoir  100  when some or all of the fluid  102  has been utilized. 
     The fluid reservoir  100  may include a barrier or barriers (e.g., wall(s)) for containing the fluid  102  (e.g., print liquid). For example, the fluid reservoir  100  may be made of a plastic, polymer, resin, thermoplastic (e.g., PP, LDPE, HDPE, PET, PC, copolymers, etc.), etc., or a combination of thermoplastics. For instance, the fluid reservoir  100  or a portion of the fluid reservoir  100  may be molded (e.g., injection molded) from a thermoplastic or thermoplastics. 
     The fluid reservoir  100  may include a routing  106 . A routing is a channel, passage, slot, or opening in a material. For example, the routing  106  may be a channel (e.g., passage through a wall) between an inside of the fluid reservoir  100  and an outside of the fluid reservoir  100 . 
     The fluid reservoir  100  may include a structure  104  contacting the routing  106  and the fluid  102  in the fluid reservoir  100 . The structure  104  may include carrier material  108  and electrically conductive non-metal material  110 . A carrier material  108  is a material that supports or carries another material. Some examples of the carrier material  108  may include plastics, polymers, resins, thermoplastics (e.g., PP, LDPE, HDPE, PET, PC, copolymers, etc.), etc., or a combination of thermoplastics. For instance, the carrier material  108  may include a polymer. 
     An electrically conductive non-metal material is a material that is electrically conductive and is not a metal. For example, the electrically conductive non-metal material  110  may be or may include graphite or carbon-graphite. In some examples, the electrically conductive non-metal material  110  may include graphite fibers. For example, the structure  104  may include a combination of polymer and graphite (e.g., graphite fibers in a resin). For instance, the structure  104  may include graphite fibers embedded in and/or through the structure  104  (e.g., carrier material  108 ). It may be beneficial to utilize conductive non-metal material instead of metal for electrical conduction in some examples. For instance, some conductive non-metal materials (e.g., graphite) may be less expensive than some metals (e.g., gold). Some conductive non-metal materials (e.g., graphite) may be more durable and/or less prone to damage than some metals (e.g., gold). For instance, a graphite-loaded plastic pin may be less prone to scratching and/or failure than a gold-coated pin. Some combinations of a conductive non-metal material (e.g., graphite) and carrier material (e.g., polymer, plastic, etc.) may provide some improved manufacturing properties relative to some metals (e.g., gold). For instance, a combination of graphite and plastic may provide better molding, welding, and/or sealing properties with plastics than gold. 
     In some examples, the structure  104  is an elongated structure that protrudes into the fluid reservoir  100 . For instance, an elongated structure may be longer than wide (or one dimension of the structure may be greater than another). In some examples, the structure  104  may be cylindrical, polygonal, prismatic, rectangular, symmetrical, asymmetrical, irregularly shaped, etc. As used herein, the term “cylindrical” may mean curved over a length. For example, “cylindrical” may denote a curved, circular, elliptical, conical, etc., shape over a length. A cylindrical structure may be partially cylindrical (e.g., cylindrical on a part of the structure) or may be cylindrical over a dimension of the structure. In some examples, cylindrical structures may be beneficial with a rotationally symmetrical shape that may oriented with any rotational orientation in a molding tool. Other shapes may be utilized in some examples. 
     In some examples, a portion of the structure  104  may be disposed on an outside of the fluid reservoir  100 . For example, the structure  104  (e.g., a portion of the structure  104 ) may be situated through the routing  106 . A portion of the structure  104  may be disposed outside of the fluid reservoir  100 , and a portion of the structure  104  may be disposed within the fluid reservoir  100 . The structure  104  may provide electrical conduction between the outside of the fluid reservoir  100  and the inside of the fluid reservoir  100 . 
     In some examples, the structure  104  may be welded to the routing  106  of the fluid reservoir  100 . In some examples, the welding between the structure  104  and the routing  106  may form a waterproof seal, which may prevent the fluid  102  from flowing out of the routing  106 . For example, welding may occur during attachment of the structure  104  to the routing  106 . In some examples, welding may occur during molding of the routing  106  (e.g., barrier or wall of the fluid reservoir) around the structure  104 . For instance, liquid material (e.g., polymer) may be injection molded around a portion of the structure  104  to form the fluid reservoir  100  or a portion of the fluid reservoir  100  (e.g., routing  106 ). The heat of the liquid material may cause the structure  104  or a portion of the structure  104  (e.g., carrier material  108 ) to undergo a phase change or partial phase change (e.g., melting, partial liquefaction, etc.), which may weld and/or bond the structure  104  to the routing  106  as the routing  106  cools and/or solidifies. In some examples, the structure  104  (e.g., carrier material  108  of the structure  104 ) and the routing  106  may have an overlapping melting temperature range. Some examples of melting temperatures of materials that may be utilized for the fluid reservoir  100 , routing  106 , and/or carrier material  108  of the structure  104  are given as follows. Polypropylene may have a melting temperature of approximately 160 degrees Celsius (C). With a blended copolymer (e.g., polypropylene with polyethene), melting temperatures may be within a range between approximately 130 C and 160 C depending on the blend. 
     In some examples, the structure  104  may be press-fit to the routing  106 . For instance, the structure  104  may include a press-fit lead-in shape. Some examples may utilize molding or press-fitting, or molding and press-fitting to attach the structure  104  to the routing  106 . 
     In some examples, silicon or silicon circuitry (not shown in  FIG.  1   ) may be in contact with the fluid  102 . The structure  104  may be utilized to mitigate (e.g., reduce, neutralize) an electrical potential (e.g., open circuit potential) between the silicon and the fluid  102 . Mitigating the electrical potential may reduce etching of the silicon. Etching of the silicon may result in degradation and/or failure of silicon circuitry (e.g., printhead). 
     In some examples, the fluid reservoir  100  may be part of the print cartridge. For instance, a print cartridge may include a printhead (not shown in  FIG.  1   ). A printhead is a structure and/or circuitry to extrude fluid (e.g., print liquid). In some examples, a printhead may include (e.g., may be manufactured with) silicon structure(s) and/or silicon-based circuitry. The printhead may be in contact with the fluid  102 . For example, silicon printhead circuitry may include a feed hole or feed holes. The feed hole(s) may permit fluid  102  (e.g., print liquid, ink, agent, etc.) to pass from the fluid reservoir  100  to be extruded by the printhead onto media. 
     In some examples, the structure  104  may be utilized to mitigate an electrical potential between the printhead and the fluid  102 . In some examples, the structure  104  may be coupled to grounding circuitry through the routing  106 . Grounding circuitry is a conductor, connection, and/or circuitry. For example, grounding circuitry may be a conductor, connection, and/or circuitry at a potential (e.g., reference potential, 0 volts (V), etc.), and/or may be a return path (e.g., common return path) for current. 
     In some examples, grounding circuitry may be coupled to a printhead. For instance, the grounding circuitry may be coupled to both the structure  104  and to a printhead that is in contact with the fluid  102 . The structure  104  may mitigate (e.g., reduce, neutralize, etc.) an electrical potential between the printhead and the fluid  102 . For example, the grounding circuitry coupled to the structure  104  and to the printhead may reduce a voltage between the fluid  102  and the printhead to a relatively small difference or zero. In some examples, the printhead may include silicon, and the structure  104  may reduce fluid etching of the silicon by mitigating the electrical potential. 
       FIG.  2    is a diagram illustrating examples of a graphite-loaded plastic pins  212   a —e. The graphite-loaded plastic pins  212   a —e may be examples of the structure  104  described in relation to  FIG.  1   . For example, each of the graphite-loaded plastic pins  212   a —e may include carrier material (e.g., plastic) and electrically conductive non-metal material (e.g., graphite). Each of the examples illustrates a top-down view and an elevation view of the graphite-loaded plastic pins  212   a —e. 
     A first graphite-loaded plastic pin  212   a  may include a first bulge  214   a  and a first head  216   a . A head of a structure is an end portion of the structure. For example, the first head  216   a  may be a cylindrical structure at an end of the first graphite-loaded plastic pin  212   a . A bulge is a portion of a structure that is larger than another portion of the structure in a dimension. For example, the first bulge  214   a  is larger in width or diameter relative to a shaft portion of the first graphite-loaded plastic pin  212   a . A shaft portion is a portion of a structure from a bulge to an end of the structure opposite from the head. An end portion of the first head  216   a  may be disposed on an outside of a fluid reservoir. In some examples, the end portion of the first head  216   a  may be coupled to grounding circuitry through a routing. In some examples, a portion of the first bulge  214   a  may be disposed within the routing and/or may be welded to the routing. For instance, a head of the structure may be placed in a mold (e.g., in a mold depression) for molding a fluid reservoir. A side of a bulge may be in contact with the mold during molding (e.g., a side towards the head). During molding, liquid material (e.g., polymer) may flow or be injected around a portion of a bulge to form a routing. The portion of the bulge may weld to the liquid material (e.g., routing). In some examples, another portion of the first bulge  214   a  may be situated in an inside of a fluid reservoir and/or may be in contact with the fluid. The first bulge  214   a  may be approximately 3 millimeters (mm) in length. The first bulge  214   a  may provide greater moldability (e.g., may be easier to manufacture) due to a larger length (in comparison with other bulges  214   b —d, for example, where the second bulge  214   b  may have a length of 0.7 mm). 
     A shaft portion of the first graphite-loaded plastic pin  212   a  may be situated in an inside of the fluid reservoir and/or may be in contact with the fluid. The shaft portion of the first graphite-loaded plastic pin  212   a  may be conical in shape. For example, the shaft portion may taper to a smaller diameter (over a portion of the length or over the entire length of the shaft portion, for instance) towards an end that is opposite from the first head  216   a . A shaft diameter of the first graphite-loaded plastic pin  212   a  may be 400 micrometers (μm) larger than a shaft diameter of a second graphite-loaded plastic pin  212   b . A larger diameter shaft may provide a larger surface area that is in contact with the fluid, which may increase the efficacy of the structure in reducing or neutralizing etching. For instance, the first graphite-loaded plastic pin  212   a  may have a surface area of 49.6 mm 2  in contact with fluid, while the second graphite-loaded plastic pin  212   b  may have a surface area of 26.6 mm 2  in contact with fluid. 
     A second graphite-loaded plastic pin  212   b  may include a second bulge  214   b  and a second head  216   b . The second head  216   b  may be a cylindrical structure at an end of the second graphite-loaded plastic pin  212   b . An end portion of the second head  216   b  may be disposed on an outside of a fluid reservoir. In some examples, the end portion of the second head  216   b  may be coupled to grounding circuitry through a routing. In some examples, a portion of the second bulge  214   b  (e.g., an entire outer circumference) may be disposed within the routing and/or may be welded to the routing. The portion of the second bulge  214   b  may weld to the liquid material (e.g., routing). In some examples, the second bulge  214   b  may not be in contact with the fluid. The second bulge  214   b  may be approximately 0.7 mm in length. The second bulge  214   b  may provide less moldability (e.g., may be more difficult to manufacture) due to a shorter length (in comparison with the first bulge  214   a , for example). 
     A shaft portion of the second graphite-loaded plastic pin  212   b  (or a portion of the shaft portion, for example) may be situated in an inside of the fluid reservoir and/or may be in contact with the fluid. The shaft portion of the second graphite-loaded plastic pin  212   b  may be cylindrical in shape with a taper  213  over a portion of the shaft (which may be utilized as a press-fit lead-in in some examples). For example, the shaft portion may taper to a smaller diameter (over the portion of the length of the shaft portion, for instance) towards an end that is opposite from the second head  216   b.    
     A third graphite-loaded plastic pin  212   c  may include a third bulge  214   c  and a third head  216   c . The third head  216   c  may be an undercut cylindrical structure at an end of the third graphite-loaded plastic pin  212   c . The undercut is a narrowed portion of the head. In some examples, the undercut may provide a mechanical interlock with conductive adhesive for coupling the third head  216   c  to grounding circuitry. An end portion of the third head  216   c  may be disposed on an outside of a fluid reservoir. In some examples, the end portion of the third head  216   c  may be coupled to grounding circuitry through a routing. In some examples, a portion of the third bulge  214   c  (e.g., an entire outer circumference) may be disposed within the routing and/or may be welded to the routing (during molding, for example). In some examples, the third bulge  214   c  may not be in contact with the fluid. The third bulge  214   c  may be approximately 1 mm in length. 
     A shaft portion of the third graphite-loaded plastic pin  212   c  (or a portion of the shaft portion, for example) may be situated in an inside of the fluid reservoir and/or may be in contact with the fluid. The shaft portion of the third graphite-loaded plastic pin  212   c  may be conical in shape with a taper over the shaft. For example, the shaft portion may taper to a smaller diameter (over the length of the shaft portion, for instance) towards an end that is opposite from the third head  216   c.    
     A fourth graphite-loaded plastic pin  212   d  may include a fourth bulge  214   d  and a fourth head  216   d . The fourth head  216   d  may be a cross-shaped structure at an end of the fourth graphite-loaded plastic pin  212   d . In some examples, the cross-shaped structure may provide increased surface area for conductive adhesive for coupling the fourth head  216   d  to grounding circuitry. An end portion of the fourth head  216   d  may be disposed on an outside of a fluid reservoir. In some examples, the end portion of the fourth head  216   d  may be coupled to grounding circuitry through a routing. In some examples, a portion of the fourth bulge  214   d  (e.g., an entire outer circumference) may be disposed within the routing and/or may be welded to the routing (during molding, for example). In some examples, the fourth bulge  214   d  may not be in contact with the fluid. The fourth bulge  214   d  may be approximately 1 mm in length. 
     A shaft portion of the fourth graphite-loaded plastic pin  212   d  (or a portion of the shaft portion, for example) may be situated in an inside of the fluid reservoir and/or may be in contact with the fluid. The shaft portion of the fourth graphite-loaded plastic pin  212   d  may be conical in shape with a taper over the shaft. For example, the shaft portion may taper to a smaller diameter (over the length of the shaft portion, for instance) towards an end that is opposite from the fourth head  216   d.    
     A fifth graphite-loaded plastic pin  212   e  may include a fifth bulge  214   e  and a fifth head  216   e . The fifth head  216   e  may be a partially cylindrical structure with an integrated rail at an end of the fifth graphite-loaded plastic pin  212   e . The fifth graphite-loaded plastic pin  212   e  may also include wing structures  215 . In some examples, the wing structures  215  may act as keying features to orient the pin  212   e  in a mold tool, as the pin  212   e  is not rotationally symmetrical. The wing structures  215  may fit into negative spaces in the mold tool to hold the pin  212   e  to provide a target orientation and/or rotation relative to the mold tool. In some examples, the partially cylindrical structure with a rail may provide a surface on which to dispense conductive adhesive. Using the rail as a dispense surface for conductive adhesive may enable a line dispense (rather than a dollop dispense, for instance). In some examples, a line dispense may be easier to control during processing. For instance, other dispensing approaches may have more factors to control when separately starting and stopping dispensing. An end portion of the fifth head  216   e  may be disposed on an outside of a fluid reservoir. In some examples, the end portion of the fifth head  216   e  may be coupled to grounding circuitry through a routing. In some examples, a portion of the fifth bulge  214   e  (e.g., an entire outer circumference) may be disposed within the routing and/or may be welded to the routing (during molding, for example). In some examples, the fifth bulge  214   e  may not be in contact with the fluid. The fifth bulge  214   e  may be approximately 1 mm in length. 
     A shaft portion of the fifth graphite-loaded plastic pin  212   e  (or a portion of the shaft portion, for example) may be situated in an inside of the fluid reservoir and/or may be in contact with the fluid. The shaft portion of the fifth graphite-loaded plastic pin  212   e  may be conical in shape with a taper over the shaft. For example, the shaft portion may taper to a smaller diameter (over the length of the shaft portion, for instance) towards an end that is opposite from the fifth head  216   e.    
     In some examples, features of the graphite-loaded plastic pins  212   a — e may be interchanged. For example, the third head  216   c  or the fourth head  216   d  may be interchanged with the first head  216   a  to produce a graphite-loaded plastic pin with the first bulge  214   a  and shaft structure. Other variations may be implemented. 
       FIG.  3    is a diagram illustrating an exploded view of an example of a print cartridge  332 . In some examples, a print cartridge may include a body containing print liquid and a graphite-loaded plastic pin disposed within the body and in contact with the print liquid. The pin may pass from an inside of the body to an outside of the body. In the example illustrated in  FIG.  3   , the print cartridge  332  includes flexible circuitry  328 , a printhead  330 , an intervening structure  326 , a conductive adhesive  324 , a graphite-loaded plastic pin  322 , and a body  318  that includes a routing  320 . In some examples, a print cartridge may not include all of the components described in relation to  FIG.  3   . 
     In some examples, the body  318  may be an example of the fluid reservoirs described herein (e.g., fluid reservoir  100  described in relation to  FIG.  1   ). In some examples, the graphite-loaded plastic pin  322  may be an example of the structure  104  described in relation to  FIG.  1    and/or of the graphite-loaded plastic pins  212   a —e described in relation to  FIG.  2   . In some examples, the flexible circuitry  328  may be an example of the grounding circuitry described in relation to  FIG.  1    and/or  FIG.  2   . In some examples, the routing  320  may be an example of the routings described in relation to  FIG.  1    and/or  FIG.  2    (e.g., routing  106 ). 
     In some examples, the flexible circuitry  328  may include a flexible layer or layers and a metal trace or traces. In some examples, the layer(s) may be polyimide (PI), polyethylene naphthalate (PEN), polyethylene terephthalate (PET), and/or other material(s), etc. In some examples, the layer(s) may isolate and/or protect the metal traces. For instance, the metal trace(s) may be embedded within (e.g., sandwiched between) layers. In some examples, each metal trace may include copper, nickel, palladium, gold, and/or other metal(s). In some examples, metal traces may have a thickness between 8 and 70 microns (e.g., 20 microns, 35 microns, etc.). In some examples, a flexible layer may have a thickness between 10 microns and 200 microns. In some examples, the metal trace(s) may include the grounding circuitry and/or other traces (e.g., traces for carrying control signal(s) to the printhead  330 ). In some examples, the flexible circuitry  328  may include a contact pad for coupling the grounding circuitry of the flexible circuitry  328  to a ground or common connection of a host device. A contact pad is a metal pad for contacting an interfacing structure (e.g., spring connectors, pins, etc.). 
     In some examples, the printhead  330  (e.g., silicon printhead circuitry) may be coupled to the flexible circuitry  328 . For example, the printhead  330  may be attached to the flexible circuitry  328  with wire bonds and/or adhesive. Examples of wire bonds may include metal plates, balls, pads, etc., that may be utilized to connect to (e.g., bond to, fuse to, join with, etc.) a wire or other connector. 
     In some examples, the body  318  may contain print liquid (e.g., ink, agent, etc.). The graphite-loaded plastic pin  322  may be disposed within (e.g., partially within) the body  318 . The graphite-loaded plastic pin  322  may be in contact with the print liquid. The graphite-loaded plastic pin  322  may pass from inside the body  318  to outside the body  318 . For example, the graphite-loaded plastic pin  322  may be situated or positioned within the body  318  through the routing  320 . A head of the graphite-loaded plastic pin  322  may be disposed outside of the body  318 . 
     In some examples, the body  318  may be welded to the graphite-loaded plastic pin  322 . For example, the body  318  may be molded around the graphite-loaded plastic pin  322 , such that carrier material of the graphite-loaded plastic pin  322  may be bonded and/or welded to the body  318 . 
     In some examples, the flexible circuitry  328  may be coupled to the graphite-loaded plastic pin  322 . For example, conductive adhesive  324  may couple a portion (e.g., a conductive pad, a copper pad, etc.) of the flexible circuitry  328  to the graphite-loaded plastic pin  322 . For instance, the conductive adhesive  324  may be applied to the graphite-loaded plastic pin  322  and/or to the flexible circuitry  328  (e.g., a conductive pad, copper pad, etc.), which may allow conduction between the graphite-loaded plastic pin  322  and the flexible circuitry  328 . In some examples, the conductive adhesive  324  may connect and/or adhere to the graphite-loaded plastic pin  322  and/or to the flexible circuitry  328 . 
     In some examples, the flexible circuitry  328  may be coupled to the body  318 . For example, an adhesive, welding, pressure fit, mechanical attachment, and/or other approach may be utilized to attach the flexible circuitry  328  to the body  318 . In some examples, an intervening structure  326  may be disposed between the flexible circuitry  328  and the body  318 . In some examples, the intervening structure  326  may be utilized to attach, interface, and/or seal the flexible circuitry  328  and/or printhead  330  to the body  318 . 
     In some examples, the printhead  330  (e.g., silicon printhead circuitry) may include a print liquid feed hole or print liquid feed holes. For example, the feed hole(s) may provide a path or paths for the print liquid in the body  318  to be extruded by the printhead  330 . In some examples, the feed hole(s) may be structured from silicon. 
     In some examples, the flexible circuitry  328  may reduce an electrical potential between the graphite-loaded plastic pin  322  and the printhead  330  (e.g., silicon printhead circuitry) to reduce etching of the feed holes. In some examples, reducing the electrical potential may be accomplished as described in relation to  FIG.  1    and/or  FIG.  2   . For instance, the graphite-loaded plastic pin  322  may be coupled to the flexible circuitry  328 , or to a conductive pad of the flexible circuitry  328  (using conductive adhesive  324 , for example). The flexible circuitry  328  (e.g., a conductive pad, metal pad, copper pad, etc.) may be coupled to the printhead  330  (e.g., silicon printhead circuitry). For example, the graphite-loaded plastic pin  322  and the printhead  330  may be coupled to a grounding conductor (e.g., metal trace, ribbon, plate, etc.) of the flexible circuitry  328 , which may reduce or neutralize the electrical potential between the graphite-loaded plastic pin  322  and the printhead  330 . Reducing the electrical potential may reduce etching of the feed hole(s). For example, reducing the electrical potential may reduce an electrochemical reaction between the print liquid and the printhead  330  (e.g., feed hole(s)). For instance, the graphite-loaded plastic pin  322 , the flexible circuitry  328 , and the printhead  330  may enable conduction between the print fluid and the printhead  330  in contact with the print fluid, which may reduce the electrical potential. 
       FIG.  4    is a flow diagram illustrating one example of a method  400  for manufacturing a fluid reservoir. In some examples, the method  400  may be performed by an assembly machine or machines. In some examples, the method  400  may be performed to produce the fluid reservoir  100  described in relation to  FIG.  1    and/or the print cartridge  332  described in relation to  FIG.  3   . The method  400  may include placing  402  a conductive non-metal structure in a mold. For instance, a structure (e.g., structure  104  or graphite-loaded plastic pin  212   a —e,  322 , etc.) may be placed in a mold. In some examples, an end of the structure (e.g., end of a head of the structure) may be placed flush with a pocket floor in the mold (e.g., die). In some examples, a side or a portion of a side of a bulge may be placed flush with a pedestal of the mold. 
     The method  400  may include molding  404  a fluid reservoir around the structure. For example, molten polymer may be molded (e.g., injection molded) around the structure (e.g., around a circumference of the structure, around a circumference of a bulge of the structure, etc.). In some examples, molding the reservoir may weld the structure to the reservoir. In some examples, molding the reservoir around the structure may form a seal around the structure. In some examples, the structure includes a first polymer with graphite fibers. For instance, the first polymer may be a carrier material and the graphite fibers may be a conductive non-metal material of the structure. In some examples, the reservoir includes a second polymer. 
       FIG.  5 A  is a diagram illustrating a perspective view of an example of a fluid reservoir well  536 . The fluid reservoir well  536  may be an example of a rectangular reservoir well. For example, a mold with a positive rectangular feature may be utilized to form the fluid reservoir well  536 . The fluid reservoir well  536  may be a portion of a fluid reservoir. As illustrated in  FIG.  5 A , a conductive non-metal structure  534  may be disposed in the fluid reservoir well  536 . The conductive non-metal structure  534  may be an example of the structure  104  described in relation to  FIG.  1    and/or an example of a graphite-loaded plastic pin  212   a - 212   e ,  322  described in relation to  FIG.  2    or  FIG.  3   . In some examples, the conductive non-metal structure  534  may be placed in a mold, and the fluid reservoir well  536  may be molded around the conductive non-metal structure  534  as described herein. 
       FIG.  5 B  is a diagram illustrating a cross-sectional view of an example of the conductive non-metal structure  534  described in relation to  FIG.  5 A . A cross-sectional view of a portion of a mold  537  is also illustrated. As illustrated in  FIG.  5 B , an end of the conductive non-metal structure  534  is placed in a pocket  538  in the mold  537 . A side or a portion of a side of the conductive non-metal structure  534  is also placed in contact with a pedestal  542  of the mold  537 . Material  540  of a reservoir may be molded around the conductive non-metal structure  534  and/or may weld to the conductive non-metal structure  534 , which may create a routing through the material  540  and/or a seal around the conductive non-metal structure  534 . 
     As used herein, the term “and/or” may mean an item or items. For example, the phrase “A, B, and/or C” may mean any of: A (without B and C), B (without A and C), C (without A and B), A and B (but not C), B and C (but not A), A and C (but not B), or all of A, B, and C. 
     While various examples of techniques and structures are described herein, the techniques and structures are not limited to the examples. Variations of the examples described herein may be implemented within the scope of the disclosure. For example, operations, functions, aspects, or elements of the examples described herein may be omitted or combined.