Abstract:
Methods of creating an internal channel of a fluid-ejection device are provided. One method includes encapsulating a channel core in an element of the fluid-ejection device that corresponds to the internal channel and dissolving at least a portion of the channel core.

Description:
BACKGROUND 
   Many fluid-ejection and fluid handling devices have internal channels for carrying fluids. A print head, e.g., of an ink-jet cartridge, an ink-deposition system, or the like, is an example of a fluid-ejection device that typically incorporates internal channels for delivering ink from a reservoir to a fluid-ejecting substrate, e.g., a print die, for deposition on a printable medium, such as paper. Joining components so that grooves in one component mate with corresponding grooves in another component to create internal channels within the joined components forms internal channels for many fluid-ejection devices. However, the corresponding grooves are often difficult to align, especially for complex channel patterns and/or a large number of channels. Moreover, it is difficult to obtain internal channels that do not leak, and extensive leak testing is often required. 
   Ultrasonic welding is one method of joining the components, but variations in material, part geometry, welder horns, and energy output devices often create unacceptable weld joints. Solvent and adhesive bonding is another way to join the components. However, solvents and adhesives are often difficult to apply, especially for complex channel patterns and/or a large number of channels. Moreover, various joining processes often produce particles that can result in a defective assembly. 
   SUMMARY 
   One embodiment of the present invention provides a method of creating an internal channel of a fluid-ejection or fluid handling device. The method includes encapsulating a channel core in an element of the fluid-ejection device that corresponds to the internal channel and dissolving at least a portion of the channel core. 

   
     DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view illustrating a channel core formed in a mold according to an embodiment of the present invention. 
       FIG. 2  is a perspective view illustrating a channel core disposed over a mold cavity prior encapsulation according to another embodiment of the present invention. 
       FIG. 3  is a perspective view illustrating encapsulating the channel core of  FIG. 2  with an element using the mold of  FIG. 2  according to yet another embodiment of the present invention. 
       FIG. 4  is a perspective view illustrating the element of  FIG. 3  encapsulating the channel core of  FIG. 3  after removal from the mold of  FIG. 2  according to another embodiment of the present invention. 
       FIG. 5  is a perspective view illustrating a channel in the element of  FIG. 4  formed by removing the channel core according to another embodiment of the present invention. 
       FIG. 6  is a view taken along line  6 - 6  of  FIG. 5 . 
       FIG. 7  is a perspective view illustrating channel cores encapsulated by an element according to another embodiment of the present invention. 
       FIG. 8  is a cross-sectional view of the element of  FIG. 7  taken along line  8 - 8  of  FIG. 7  illustrating channels formed by removing the channel cores according to yet another embodiment of the present invention. 
       FIG. 9  is a perspective view illustrating a threaded channel core according to another embodiment of the present invention. 
       FIG. 10  is a perspective view illustrating an element encapsulating the threaded channel core of  FIG. 9  according to yet another embodiment of the present invention. 
       FIG. 11  is a perspective view illustrating an internally threaded channel in the element of  FIG. 10  formed by removing the channel core. 
       FIG. 12  is a perspective view illustrating a grooved component according to another embodiment of the present invention. 
       FIG. 13  is an enlarged view of region  1300  of  FIG. 12 . 
       FIG. 14  is a perspective view that illustrates channel cores disposed in grooves of the component of  FIG. 12  according to yet another embodiment of the present invention. 
       FIG. 15  is a perspective view illustrating an element formed by disposing a material on the component of  FIG. 14  so as to cover the channel cores according to another embodiment of the present invention. 
       FIG. 16A  is a cross-sectional view of the element of  FIG. 15  before removal of the channel cores according to yet another embodiment of the present invention. 
       FIG. 16B  is a cross-sectional view of the element of  FIG. 15  after removal of the channel cores according to still another embodiment of the present invention. 
       FIG. 16C  is a bottom view of the element of  FIG. 15 . 
       FIG. 17  illustrates an element according to another embodiment of the present invention. 
       FIG. 18  is a perspective view illustrating a grooved component according to another embodiment of the present invention. 
       FIG. 19  is a perspective view that illustrates a channel core disposed in the groove of the component of  FIG. 18  according to yet another embodiment of the present invention. 
       FIG. 20  is a perspective view illustrating an element having an internal channel according to another embodiment of the present invention. 
       FIG. 21  illustrates a fluid-ejection cartridge according to another embodiment of the present invention. 
       FIG. 22  illustrates a fluid-deposition system according to another embodiment of the present invention. 
   

   DETAILED DESCRIPTION 
   In the following detailed description of the present embodiments, reference is made to the accompanying drawings that form a part hereof, and in which is shown by way of illustration specific embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, and it is to be understood that other embodiments may be utilized and that process, electrical or mechanical changes may be made without departing from the scope of the present invention. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is defined only by the appended claims and equivalents thereof. 
     FIGS. 1-6  illustrate formation of an internal channel, e.g., during the manufacture of a manifold, a fluid-ejection device, such as a print head, etc., according to an embodiment of the present invention.  FIG. 1  illustrates formation of a sacrificial channel core  100 . For one embodiment, channel core  100  is of a water-soluble polymer, such as polyvinyl alcohol, polyethylene oxide, or the like. Channel core  100  may be formed using any technique, such as, for example, injection molding, forming, stamping, or machining. As shown in  FIG. 1 , channel core  100  may be formed from injection molding using a mold  110 , half of which is shown in  FIG. 1 . Channel core  100  is then positioned in a mold  200 , a first half of which is shown in  FIG. 2 . In one embodiment, channel core  100  bridges a cavity  210  of mold  200  so that ends  220  and  230  respectively extend past walls  240  and  250  of cavity  210 . A second half (not shown) of mold  200  is positioned on the first half of mold  200 . A material  300 , shown in  FIG. 3 , is molded around channel core  100  by injecting material  300  into mold  200  in a molten state so as to fill cavity  210  and encapsulate (or overmold) channel core  100 . This forms an element  310  with channel core  100 . Material  300  can be a plastic, an elastomer, etc. 
   After material  300  solidifies around channel core  100 , element  310  is removed from mold  200 .  FIG. 4  illustrates element  310  with channel core  100  therein after removal from mold  200 . After removal from mold  200 , element  310  is exposed to a solvent, such as water for embodiments where channel core  100  is of a water-soluble polymer, for dissolving channel core  100  from element  310 . This may include immersing element  310  in a solvent bath until channel core  100  is dissolved. For some embodiments, increasing the solvent temperature, directing jets of solvent onto element  310 , and/or agitating the solvent bath act to reduce a time required for dissolving channel core  100 . For other embodiments, a buffer is added to the solvent bath to reduce the time required for dissolving channel core  100 . For one embodiment, the buffer is added to a water solvent to produce an aqueous solvent having a pH of about 4. For another embodiment, ends  220  and  230  of channel core  100  are alternately exposed to solvent flow. 
     FIG. 5  illustrates element  310  after channel core  100  is dissolved therefrom according to another embodiment of the present invention. Dissolution of channel core  100  creates a flow-through internal channel  320  in element  310  that is open at ends  330  and  340  thereof, as shown in  FIG. 5 .  FIG. 6  is a cross-sectional view of element  310  illustrating a cross section of channel  320 . For one embodiment, element  310  is a manifold of a fluid-ejection device, such as a print head. 
     FIG. 7  illustrates an element  700 , such as a manifold of a fluid-ejection device, e.g., a print head, that includes channel cores  710  and  720  encapsulated by material  300  according to another embodiment of the present invention. For one embodiment, channel cores  710  and  720  are as described above and are formed as described above for channel core  100  of  FIG. 1 . For another embodiment, element  700  and is formed as described above for element  310  of  FIG. 4 . 
     FIG. 8  is a cross-sectional view of element  700  after dissolving channel cores  710  and  720  therefrom, as described above.  FIG. 8  illustrates a cross section of a through-flow channel  730  that is open at ends  732  and  734  thereof and that is created by dissolving channel core  710 . Dissolving channel core  720  creates a through-flow channel  740  that is open at ends  742  and  744  thereof, as shown in  FIG. 8 . For one embodiment, channel core segments  722  and  724  of channel core  720  are in a different plane than channel core segment  726  of channel core  720 , as shown in  FIG. 7 . This means that channel  740  has segments that are in different planes, as shown in  FIG. 8 . 
     FIGS. 9-11  illustrate formation of an internally threaded internal channel according to another embodiment of the present invention.  FIG. 9  illustrates a channel core  900  having external threads  910 . For one embodiment, injection molding, using a mold having internal threads for forming external threads  910 , forms channel core  900 . For another embodiment, channel core  900  is a water-soluble polymer.  FIG. 10  illustrates an element  1000  that includes channel core  900  encapsulated by material  300  according to another embodiment of the present invention. For one embodiment, element  1000  is formed as described above for element  310  of  FIG. 4 .  FIG. 11  illustrates element  1000  after channel core  900  has been dissolved therefrom, as described above, to form an internally threaded internal channel  1010 . Note that external threads  910  of channel core  900  create internal threads  1020  of channel  1010 . For one embodiment, element  1000  is manifold of a fluid ejection device, such as a print head. 
     FIGS. 12-15  illustrate formation of internal channels according to another embodiment of the present invention.  FIG. 12  and  FIG. 13 , an enlarged view of region  1300  of  FIG. 12 , illustrate a component  1200  having grooves  1210   1  to  1210   N . For one embodiment, injection molding forms component  1200 . That is, a material, e.g., plastic, an elastomer, etc., is injected into a mold patterned to create component  1200 . For another embodiment, each of grooves  1210   1  to  1210   N  is located between ribs  1220  and  1230 , as shown in  FIG. 13 . For another embodiment, ribs  1220  and  1230  protrude from a surface  1250  of component  1200  so that a surface  1240  of ribs  1220  and  1230  is above and is substantially parallel to surface  1250 , as shown in  FIG. 13 . 
   For one embodiment, grooves  1210   1  to  1210   N  respectively intersect holes  1260   1  to  1260   N  at one end of the respective grooves, as shown in  FIG. 12 , that pass completely through component  1200  and that, for another embodiment, are substantially perpendicular to grooves  1210   1  to  1210   N . For other embodiments, grooves  1210   1  to  1210   N  respectively include end regions  1270   1  to  1270   N , as shown in  FIGS. 12 and 13 . 
   After the formation of component  1200 , a material  1275  in a liquid state, e.g., a water-soluble polymer, such as polyvinyl alcohol, polyethylene oxide, or the like, is disposed in grooves  1210 , as illustrated for grooves  1210   1  to  1210   3  in  FIG. 14 . Solidification of the material forms sacrificial channel cores in each of grooves  1210 . As an example,  FIG. 14  illustrates channel cores  1280   1  to  1280   3  respectively formed in grooves  1210   1  to  1210   3 . For one embodiment, a plate (not shown) is disposed on component  1200  before disposing material  1275  in grooves  1210 . Specifically, the plate is butted against surfaces  1240  of ribs  1220  and  1230 . For one embodiment, material  1275  is injected into grooves  1210  through holes  1260  or through holes in the plate that align with grooves  1210 . 
   After forming the channel cores, an element  1500 , shown in  FIG. 15  is formed by disposing a material  1510 , such as an elastomer, plastic, etc., on component  1200  so as to cover the channel cores. In this way, the channel cores are encapsulated by element  1500 . For one embodiment, component  1200  is placed in a mold and material  1510  is injected in liquid form into the mold to dispose material  1510  on component  1200 . For another embodiment, material  1510 , in liquid form, is sprayed on component  1200  or spread on component  1200 , e.g., using a spreading device, such as a spreader bar, a brush, etc. 
   Element  1500  is then exposed to a solvent, such as water for embodiments where the channel cores are of a water-soluble polymer, for dissolving the channel cores from grooves  1210  to create internal channels within element  1500  corresponding to grooves  1210 . Exposing element  1500  to a solvent may include immersing element  1500  in a solvent bath until the channel cores are dissolved. For some embodiments, increasing the solvent temperature, directing jets of solvent onto element  1500 , and/or agitating the solvent bath act to reduce a time required for dissolving the channel cores. For other embodiments, a buffer is added to the solvent bath to reduce the time required for dissolving the channel cores. For one embodiment, the buffer is added to a water solvent to produce an aqueous solvent having a pH of about 4. 
   For one embodiment, holes are formed in material  1510  that align with end regions  1270  of grooves  1210 . For example,  FIG. 15  illustrates holes  1520   1  to  1520   3  passing through a top surface  1515  of material  1510  (and thus of element  1500 ) that respectively align with end regions  1270   1  to  1270   3  respectively of grooves  1210   1  to  1210   3 . 
   For one embodiment, holes  1520  are formed as illustrated in  FIGS. 16A and 16B , cross-sectional views of element  1500 . In this embodiment, component  1200  is formed so that a conduit  1610  extends from each of the end regions  1270  of each of grooves  1210 . A channel core  1280  is formed in conduit  1610 , groove  1210 , and hole  1260 . Material  1275  is injected into conduit  1610 , groove  1210 , and hole  1260  through conduit  1610  or hole  1260 , for example. Material  1510  is disposed on component  1200  and around conduit  1610  so that conduit  1610  passes completely through material  1510 , as shown in  FIG. 16A . Channel core  1280  is then dissolved, as described above, to form an internal channel  1620 , corresponding to groove  1210 , that interconnects hole  1260  and hole  1520 , as shown in  FIG. 16B . During dissolution of channel core  1280 , the solvent accesses channel core  1280  through conduit  1610  and hole  1260 . For some embodiments, conduit  1610  and hole  1260  are alternately exposed to a solvent flow. For one embodiment, holes  1260  and  1520  are respectively an outlet and inlet of channel  1620  and thus of element  1500  or vice versa. 
     FIG. 16C  is a bottom view of element  1500 . For one embodiment, the holes  1260  terminate at a bottom surface  1285  of component  1200  (and thus of element  1500 ), as shown in  FIG. 16C . For one embodiment, element  1500  is a manifold of a fluid-ejection device, such as a print head. For another embodiment, holes  1260  lie within a region  1630  of bottom surface  1285 . For some embodiments, a fluid-ejecting substrate, such as a print-head die (not shown) is disposed within region  1630  so that the fluid-ejecting substrate is fluidly coupled to the internal channels by holes  1260 . For these embodiments, a fluid, such as ink, enters element  1500  through holes  1520 , flows through channels  1620 , exits element  1500  through holes  1260 , and flows into the fluid-ejecting substrate. 
     FIG. 17  illustrates an element  1700  according to another embodiment of the present invention. Element  1700  includes a material  1710 , such as plastic, an elestomer, etc., disposed on a component  1720 . Element  1700  also includes internal channels  1730 . For one embodiment, internal channels  1730  terminate at openings  1740  in a side  1750  of component  1720 . For this embodiment, internal channels  1730  can connect openings  1740  to holes (not shown) passing through a top surface  1760  of material  1710 , holes (not shown) passing through a bottom surface  1770  of component  1720 , and/or other openings (not shown) in sidewall  1750 , an end-wall  1780  of component  1720 , a sidewall opposite sidewall  1750  and/or an end-wall opposite end-wall  1780 . 
   For another embodiment, component  1720  having grooves corresponding to internal channels  1730  is formed by injection molding, as described above for component  1200 . Sacrificial channel cores are then disposed in the grooves, as described above for component  1200 . Material  1710  is then disposed on component  1720  so that element  1700  encapsulates the channel cores. The channel cores are dissolved, as described above for element  1500  to create internal channels  1730  corresponding to the grooves. For one embodiment, element  1700  is a manifold of a fluid-ejection device such as a print head. 
     FIG. 18  illustrates a component  1800  having a groove  1810 . For one embodiment, component  1800  is formed by injection molding, as described above for component  1200 . Component  1800  can be plastic, an elastomer, etc. An internal surface  1811  of groove  1810  includes internal surfaces  1812  and  1814  that lie in different planes and that are interconnected, for one embodiment, by an inclined internal surface  1816 . Therefore, ends  1818  and  1820  of groove  1810  are in different planes. For one embodiment, surfaces  1812  and  1814  are substantially parallel, and inclined surface  1816  forms at most a 45-degree angle with surfaces  1812  and  1814 . For another embodiment, groove  1810  is located between ribs  1830  and  1840  protruding from a surface  1860  of component  1800 . Each ribs  1830  and  1840  has a surface  1850  that substantially parallels internal surface  1811  of groove  1810 . For other embodiments, surface  1860  of component  1800  substantially parallels internal surface  1811  of groove  1810 . 
   After the formation of component  1800 , a material  1900  in a liquid state, e.g., a water-soluble polymer, such as polyvinyl alcohol, polyethylene oxide, or the like, is disposed in groove  1810 , as illustrated in  FIG. 19 . Solidification of material  1900  forms a sacrificial channel core  1910  in groove  1810 . For one embodiment, a plate (not shown) that fits the shape of surface  1850  of each of ribs  1830  and  1840  is butted against surface  1850  of each of ribs  1830  and  1840 , and material  1900  is injected into groove  1810 , e.g., through ends  1818  and/or  1820  (shown in  FIG. 18 ) of groove  1810  and/or through holes in the plate that align with groove  1810 . 
   After forming channel core  1910 , an element  2000 , shown in  FIG. 20 , is formed by disposing a material  2010 , such as an elastomer, plastic, etc., on component  1800  so as to cover channel core  1910  so that element  2000  encapsulates channel core  1910 . For one embodiment, element  2000  is placed in a mold and material  2010  is injected in liquid form into the mold to dispose material  2010  on component  1800 . For another embodiment, material  2010 , in liquid form, is sprayed on component  1800  or spread on component  1800 , e.g., using a spreading device, such as a spreader bar, a brush, etc. Channel core  1910  is then dissolved, as described above for element  1500 , to form an internal channel  2020  corresponding to groove  1810  within element  2000 . 
   Note that end  1818  of groove  1810  corresponds to an opening in element  2000 , as shown in  FIG. 20 , that can be used, for example, as an inlet of internal channel  2020 . End  1820  of groove  1810  also corresponds to an opening in element  2000  (not shown) that can be used, for example, as an outlet of internal channel  2020 . Note that the inlet and outlet of internal channel  2020  respectively corresponding to ends  1818  and  1820  of groove  1810  are located in different planes of element  2000 , because ends  1818  and  1820  are located in different planes of component  1800 . For one embodiment, element  2000  is a manifold of a fluid-ejection device, such as a print head. 
   For some embodiments, the channel cores of the present invention are of composite materials including particles, e.g., insoluble particles, such as glass, etc., dispersed in a soluble material, e.g., water-soluble polymer. This reduces the amount of soluble material that needs to be dissolved when removing the channel cores. To remove a channel core, for one embodiment, the soluble material is dissolved, leaving the particles within the channel. The particles are then washed from the channel, for example, using a flow of the solvent. 
   For some embodiments, in order to facilitate or promote the removal of one or more channel cores, energy, such as infrared, laser, ultrasonic energy, or the like, is selectively directed at the core, or at various parts of the core, while the encapsulated core is in the water bath. For other embodiments, the material encapsulating the channel core is a transmissive material, e.g., clear polypropylene, and allows the energy to pass through the encapsulating material and into the channel cores without substantially heating the encapsulating material. For example, the energy excites the core so that the core generates heat and thereby attains a temperature that is greater than the temperature attained by the encapsulating material. For some embodiments, the channel core is an energy absorptive material, such as a water-soluble polymer, e.g., polyvinyl alcohol, polyethylene oxide, etc., having pigments, such as carbon black, added thereto. The energy directed at the core acts to excite the core, resulting in heating of the core. Heating acts to improve solubility and can reduce the viscosity of the core material laden solvent adjacent the core. 
   For another embodiment, the channel core is not dissolved from the encapsulating material. Instead the energy directed at the core by the above methods melts the core from the encapsulating material. For this embodiment, the energy passes through the transmissive encapsulating material without substantially heating the encapsulating material and is absorbed by the energy-absorbing core. For example, the energy excites the core so that the core generates heat and thereby attains a temperature that is greater than the temperature attained by the encapsulating material, causing the core to melt. For some embodiments, the encapsulating material has a higher melting temperature than the core, so that the core can be melted without melting the encapsulating material. 
   For another embodiment, the core is heated within the encapsulating material without substantially heating the encapsulating material by disposing magnetic particles, such as metal particles, within the core and exciting the particles with magnetic resonance. 
     FIG. 21  illustrates a fluid-ejection cartridge  2100 , such as an ink-jet cartridge, according to another embodiment of the present invention. Fluid-ejection cartridge  2100  includes a fluid reservoir  2110 , such as an ink reservoir, that for one embodiment is integral with a manifold  2120  of a fluid-ejection device  2130 , e.g., a print head. Fluid-ejection device  2130  is capable of ejecting fluid, such as ink, onto media, such as paper. Manifold  2120  includes internal channels  2140 , e.g., ink-delivery channels. For one embodiment, manifold  2120  and internal channels  2140  are formed according to the teachings of the present invention. Fluid-ejection device  2130  includes a fluid-ejecting substrate  2150 , such as a print head die, disposed on manifold  2120 , such as by gluing. Internal channels  2140  fluidly couple fluid reservoir  2110  to fluid-ejecting substrate  2150 . Specifically, internal channels  2140  fluidly couple fluid reservoir  2110  to orifices  2160  of fluid-ejecting substrate  2150 . For one embodiment, orifices  2160  are formed directly in fluid-ejecting substrate  2150  and constitute an orifice layer of fluid-ejecting substrate  2150 . For another embodiment, orifices  2160  pass through an orifice plate  2170  disposed on fluid-ejecting substrate  2150 . For another embodiment, resistors  2180  of fluid-ejecting substrate  2150  are fluidly coupled between internal channels  2140  and orifices  2160 . For some embodiments, resistors  2180  are formed on fluid-ejecting substrate  2150  using semi-conductor processing methods, as is well known in the art. 
   In operation, fluid reservoir  2110  supplies fluid, such as ink, to fluid-ejection device  2130 . Internal channels  2140  deliver the fluid to fluid-ejecting substrate  2150 . The fluid is channeled to resistors  2180 . Resistors  2180  are selectively energized to rapidly heat the fluid, causing the fluid to be expelled through orifices  2160  in the form of droplets  2190 . For some embodiments, droplets  2190  are deposited onto a medium  2195 , e.g., paper, as fluid-ejection cartridge  2100  is carried over medium  2195  by a movable carriage (not shown) of an imaging device (not shown), such as a printer, fax machine, or the like. 
     FIG. 22  illustrates a fluid-deposition system  2200 , e.g., an ink deposition system, according to another embodiment of the present invention. For one embodiment, fluid-deposition system  2200  includes fluid-ejection devices  2210  and  2220 , e.g., print heads, connected to a manifold  2230 . For another embodiment, each of fluid-ejection devices  2210  and  2220  is constructed according to the present invention. For other embodiments, each of fluid-ejection devices  2210  and  2220  is as described above for fluid-ejection device  2130  of  FIG. 21 . For these embodiments, common reference numbers are used for each of fluid-ejection devices  2210  and  2220  and fluid-ejection device  2130  of  FIG. 21 . 
   For one embodiment, ducts  2215  and  2225  respectively fluidly couple fluid-ejection devices  2210  and  2220  to manifold  2230 . Specifically, internal channels  2140  of manifolds  2120  of fluid-ejection devices  2210  and  2220  fluidly couple fluid-ejecting substrates  2150  of fluid-ejection devices  2210  and  2220  to ducts  2215  and  2225 . Ducts  2215  and  2225  can either be flexible or substantially rigid. For another embodiment, ducts  2215  and  2225  are respectively fluidly coupled to internal channels  2232  and  2234  of manifold  2230 . For another embodiment, manifold  2230  and internal channels  2232  and  2234  are formed according to the present invention. For some embodiments, ducts  2240  and  2245 , e.g., either flexible or substantially rigid, fluidly couple manifold  2230  to a fluid reservoir  2250 , e.g., an ink reservoir. Specifically, ducts  2240  and  2245  are respectively fluidly coupled to internal channels  2232  and  2234  of manifold  2230 . 
   For one embodiment, manifold  2230  and fluid-ejection devices  2210  and  2220  are disposed on a movable carriage (not shown) of an imaging device (not shown), such as a printer, fax machine, or the like, while fluid reservoir  2250  is fixed to the imaging device remotely to manifold  2230  and fluid-ejection devices  2210  and  2220 . For another embodiment, fluid-ejection devices  2210  and  2220  are fluidly coupled directly to manifold  2230  without using ducts  2215  and  2225 . Specifically, fluid-ejection devices  2210  and  2220  are respectively fluidly coupled directly to internal channels  2232  and  2234  by manifolds  2120  of each of fluid-ejection devices  2210  and  2220 . 
   During operation, for one embodiment, fluid droplets  2190 , e.g., ink droplets, are deposited onto a medium  2260 , e.g., paper, by fluid-ejection device  2210  and/or fluid-ejection device  2220  as fluid-ejection devices  2210  and  2220  are carried over medium  2260  by the movable carriage, while fluid reservoir  2250  remains stationary. For this embodiment, ducts  2240  and  2245  are flexible so as to enable fluid-ejection devices  2210  and  2220  to move relative to fluid reservoir  2250 . 
   For another embodiment, manifold  2230  is fluidly coupled directly to fluid reservoir  2250  without using ducts  2240  and  2245 . For this embodiment, fluid-ejection devices  2210  and  2220  are disposed on the movable carriage of the imaging device, while fluid reservoir  2250  and manifold  2230  are fixed to the imaging device remotely to fluid-ejection devices  2210  and  2220 . For other embodiments, fluid reservoir  2250  delivers black ink to fluid-ejection device  2210  and colored ink to fluid-ejection device  2220 . 
   For various embodiments, the manifolds and internal channels formed according to the present invention can be used in medical devices that are for delivering various medications to patients or that are used during the manufacture of medications. 
   CONCLUSION  
   Although specific embodiments have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that any arrangement that is calculated to achieve the same purpose may be substituted for the specific embodiments shown. Many adaptations of the invention will be apparent to those of ordinary skill in the art. Accordingly, this application is intended to cover any adaptations or variations of the invention. It is manifestly intended that this invention be limited only by the following claims and equivalents thereof.