Methods for creating channels

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.

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.

DETAILED DESCRIPTION

FIGS. 1-6illustrate 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. 1illustrates formation of a sacrificial channel core100. For one embodiment, channel core100is of a water-soluble polymer, such as polyvinyl alcohol, polyethylene oxide, or the like. Channel core100may be formed using any technique, such as, for example, injection molding, forming, stamping, or machining. As shown inFIG. 1, channel core100may be formed from injection molding using a mold110, half of which is shown inFIG. 1. Channel core100is then positioned in a mold200, a first half of which is shown inFIG. 2. In one embodiment, channel core100bridges a cavity210of mold200so that ends220and230respectively extend past walls240and250of cavity210. A second half (not shown) of mold200is positioned on the first half of mold200. A material300, shown inFIG. 3, is molded around channel core100by injecting material300into mold200in a molten state so as to fill cavity210and encapsulate (or overmold) channel core100. This forms an element310with channel core100. Material300can be a plastic, an elastomer, etc.

After material300solidifies around channel core100, element310is removed from mold200.FIG. 4illustrates element310with channel core100therein after removal from mold200. After removal from mold200, element310is exposed to a solvent, such as water for embodiments where channel core100is of a water-soluble polymer, for dissolving channel core100from element310. This may include immersing element310in a solvent bath until channel core100is dissolved. For some embodiments, increasing the solvent temperature, directing jets of solvent onto element310, and/or agitating the solvent bath act to reduce a time required for dissolving channel core100. For other embodiments, a buffer is added to the solvent bath to reduce the time required for dissolving channel core100. 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, ends220and230of channel core100are alternately exposed to solvent flow.

FIG. 5illustrates element310after channel core100is dissolved therefrom according to another embodiment of the present invention. Dissolution of channel core100creates a flow-through internal channel320in element310that is open at ends330and340thereof, as shown inFIG. 5.FIG. 6is a cross-sectional view of element310illustrating a cross section of channel320. For one embodiment, element310is a manifold of a fluid-ejection device, such as a print head.

FIG. 7illustrates an element700, such as a manifold of a fluid-ejection device, e.g., a print head, that includes channel cores710and720encapsulated by material300according to another embodiment of the present invention. For one embodiment, channel cores710and720are as described above and are formed as described above for channel core100ofFIG. 1. For another embodiment, element700and is formed as described above for element310ofFIG. 4.

FIG. 8is a cross-sectional view of element700after dissolving channel cores710and720therefrom, as described above.FIG. 8illustrates a cross section of a through-flow channel730that is open at ends732and734thereof and that is created by dissolving channel core710. Dissolving channel core720creates a through-flow channel740that is open at ends742and744thereof, as shown inFIG. 8. For one embodiment, channel core segments722and724of channel core720are in a different plane than channel core segment726of channel core720, as shown inFIG. 7. This means that channel740has segments that are in different planes, as shown inFIG. 8.

FIGS. 9-11illustrate formation of an internally threaded internal channel according to another embodiment of the present invention.FIG. 9illustrates a channel core900having external threads910. For one embodiment, injection molding, using a mold having internal threads for forming external threads910, forms channel core900. For another embodiment, channel core900is a water-soluble polymer.FIG. 10illustrates an element1000that includes channel core900encapsulated by material300according to another embodiment of the present invention. For one embodiment, element1000is formed as described above for element310ofFIG. 4.FIG. 11illustrates element1000after channel core900has been dissolved therefrom, as described above, to form an internally threaded internal channel1010. Note that external threads910of channel core900create internal threads1020of channel1010. For one embodiment, element1000is manifold of a fluid ejection device, such as a print head.

FIGS. 12-15illustrate formation of internal channels according to another embodiment of the present invention.FIG. 12andFIG. 13, an enlarged view of region1300ofFIG. 12, illustrate a component1200having grooves12101to1210N. For one embodiment, injection molding forms component1200. That is, a material, e.g., plastic, an elastomer, etc., is injected into a mold patterned to create component1200. For another embodiment, each of grooves12101to1210Nis located between ribs1220and1230, as shown inFIG. 13. For another embodiment, ribs1220and1230protrude from a surface1250of component1200so that a surface1240of ribs1220and1230is above and is substantially parallel to surface1250, as shown inFIG. 13.

For one embodiment, grooves12101to1210Nrespectively intersect holes12601to1260Nat one end of the respective grooves, as shown inFIG. 12, that pass completely through component1200and that, for another embodiment, are substantially perpendicular to grooves12101to1210N. For other embodiments, grooves12101to1210Nrespectively include end regions12701to1270N, as shown inFIGS. 12 and 13.

After the formation of component1200, a material1275in a liquid state, e.g., a water-soluble polymer, such as polyvinyl alcohol, polyethylene oxide, or the like, is disposed in grooves1210, as illustrated for grooves12101to12103inFIG. 14. Solidification of the material forms sacrificial channel cores in each of grooves1210. As an example,FIG. 14illustrates channel cores12801to12803respectively formed in grooves12101to12103. For one embodiment, a plate (not shown) is disposed on component1200before disposing material1275in grooves1210. Specifically, the plate is butted against surfaces1240of ribs1220and1230. For one embodiment, material1275is injected into grooves1210through holes1260or through holes in the plate that align with grooves1210.

After forming the channel cores, an element1500, shown inFIG. 15is formed by disposing a material1510, such as an elastomer, plastic, etc., on component1200so as to cover the channel cores. In this way, the channel cores are encapsulated by element1500. For one embodiment, component1200is placed in a mold and material1510is injected in liquid form into the mold to dispose material1510on component1200. For another embodiment, material1510, in liquid form, is sprayed on component1200or spread on component1200, e.g., using a spreading device, such as a spreader bar, a brush, etc.

Element1500is 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 grooves1210to create internal channels within element1500corresponding to grooves1210. Exposing element1500to a solvent may include immersing element1500in a solvent bath until the channel cores are dissolved. For some embodiments, increasing the solvent temperature, directing jets of solvent onto element1500, 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 material1510that align with end regions1270of grooves1210. For example,FIG. 15illustrates holes15201to15203passing through a top surface1515of material1510(and thus of element1500) that respectively align with end regions12701to12703respectively of grooves12101to12103.

For one embodiment, holes1520are formed as illustrated inFIGS. 16A and 16B, cross-sectional views of element1500. In this embodiment, component1200is formed so that a conduit1610extends from each of the end regions1270of each of grooves1210. A channel core1280is formed in conduit1610, groove1210, and hole1260. Material1275is injected into conduit1610, groove1210, and hole1260through conduit1610or hole1260, for example. Material1510is disposed on component1200and around conduit1610so that conduit1610passes completely through material1510, as shown inFIG. 16A. Channel core1280is then dissolved, as described above, to form an internal channel1620, corresponding to groove1210, that interconnects hole1260and hole1520, as shown inFIG. 16B. During dissolution of channel core1280, the solvent accesses channel core1280through conduit1610and hole1260. For some embodiments, conduit1610and hole1260are alternately exposed to a solvent flow. For one embodiment, holes1260and1520are respectively an outlet and inlet of channel1620and thus of element1500or vice versa.

FIG. 16Cis a bottom view of element1500. For one embodiment, the holes1260terminate at a bottom surface1285of component1200(and thus of element1500), as shown inFIG. 16C. For one embodiment, element1500is a manifold of a fluid-ejection device, such as a print head. For another embodiment, holes1260lie within a region1630of bottom surface1285. For some embodiments, a fluid-ejecting substrate, such as a print-head die (not shown) is disposed within region1630so that the fluid-ejecting substrate is fluidly coupled to the internal channels by holes1260. For these embodiments, a fluid, such as ink, enters element1500through holes1520, flows through channels1620, exits element1500through holes1260, and flows into the fluid-ejecting substrate.

FIG. 17illustrates an element1700according to another embodiment of the present invention. Element1700includes a material1710, such as plastic, an elestomer, etc., disposed on a component1720. Element1700also includes internal channels1730. For one embodiment, internal channels1730terminate at openings1740in a side1750of component1720. For this embodiment, internal channels1730can connect openings1740to holes (not shown) passing through a top surface1760of material1710, holes (not shown) passing through a bottom surface1770of component1720, and/or other openings (not shown) in sidewall1750, an end-wall1780of component1720, a sidewall opposite sidewall1750and/or an end-wall opposite end-wall1780.

For another embodiment, component1720having grooves corresponding to internal channels1730is formed by injection molding, as described above for component1200. Sacrificial channel cores are then disposed in the grooves, as described above for component1200. Material1710is then disposed on component1720so that element1700encapsulates the channel cores. The channel cores are dissolved, as described above for element1500to create internal channels1730corresponding to the grooves. For one embodiment, element1700is a manifold of a fluid-ejection device such as a print head.

FIG. 18illustrates a component1800having a groove1810. For one embodiment, component1800is formed by injection molding, as described above for component1200. Component1800can be plastic, an elastomer, etc. An internal surface1811of groove1810includes internal surfaces1812and1814that lie in different planes and that are interconnected, for one embodiment, by an inclined internal surface1816. Therefore, ends1818and1820of groove1810are in different planes. For one embodiment, surfaces1812and1814are substantially parallel, and inclined surface1816forms at most a 45-degree angle with surfaces1812and1814. For another embodiment, groove1810is located between ribs1830and1840protruding from a surface1860of component1800. Each ribs1830and1840has a surface1850that substantially parallels internal surface1811of groove1810. For other embodiments, surface1860of component1800substantially parallels internal surface1811of groove1810.

After the formation of component1800, a material1900in a liquid state, e.g., a water-soluble polymer, such as polyvinyl alcohol, polyethylene oxide, or the like, is disposed in groove1810, as illustrated inFIG. 19. Solidification of material1900forms a sacrificial channel core1910in groove1810. For one embodiment, a plate (not shown) that fits the shape of surface1850of each of ribs1830and1840is butted against surface1850of each of ribs1830and1840, and material1900is injected into groove1810, e.g., through ends1818and/or1820(shown inFIG. 18) of groove1810and/or through holes in the plate that align with groove1810.

After forming channel core1910, an element2000, shown inFIG. 20, is formed by disposing a material2010, such as an elastomer, plastic, etc., on component1800so as to cover channel core1910so that element2000encapsulates channel core1910. For one embodiment, element2000is placed in a mold and material2010is injected in liquid form into the mold to dispose material2010on component1800. For another embodiment, material2010, in liquid form, is sprayed on component1800or spread on component1800, e.g., using a spreading device, such as a spreader bar, a brush, etc. Channel core1910is then dissolved, as described above for element1500, to form an internal channel2020corresponding to groove1810within element2000.

Note that end1818of groove1810corresponds to an opening in element2000, as shown inFIG. 20, that can be used, for example, as an inlet of internal channel2020. End1820of groove1810also corresponds to an opening in element2000(not shown) that can be used, for example, as an outlet of internal channel2020. Note that the inlet and outlet of internal channel2020respectively corresponding to ends1818and1820of groove1810are located in different planes of element2000, because ends1818and1820are located in different planes of component1800. For one embodiment, element2000is 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. 21illustrates a fluid-ejection cartridge2100, such as an ink-jet cartridge, according to another embodiment of the present invention. Fluid-ejection cartridge2100includes a fluid reservoir2110, such as an ink reservoir, that for one embodiment is integral with a manifold2120of a fluid-ejection device2130, e.g., a print head. Fluid-ejection device2130is capable of ejecting fluid, such as ink, onto media, such as paper. Manifold2120includes internal channels2140, e.g., ink-delivery channels. For one embodiment, manifold2120and internal channels2140are formed according to the teachings of the present invention. Fluid-ejection device2130includes a fluid-ejecting substrate2150, such as a print head die, disposed on manifold2120, such as by gluing. Internal channels2140fluidly couple fluid reservoir2110to fluid-ejecting substrate2150. Specifically, internal channels2140fluidly couple fluid reservoir2110to orifices2160of fluid-ejecting substrate2150. For one embodiment, orifices2160are formed directly in fluid-ejecting substrate2150and constitute an orifice layer of fluid-ejecting substrate2150. For another embodiment, orifices2160pass through an orifice plate2170disposed on fluid-ejecting substrate2150. For another embodiment, resistors2180of fluid-ejecting substrate2150are fluidly coupled between internal channels2140and orifices2160. For some embodiments, resistors2180are formed on fluid-ejecting substrate2150using semi-conductor processing methods, as is well known in the art.

In operation, fluid reservoir2110supplies fluid, such as ink, to fluid-ejection device2130. Internal channels2140deliver the fluid to fluid-ejecting substrate2150. The fluid is channeled to resistors2180. Resistors2180are selectively energized to rapidly heat the fluid, causing the fluid to be expelled through orifices2160in the form of droplets2190. For some embodiments, droplets2190are deposited onto a medium2195, e.g., paper, as fluid-ejection cartridge2100is carried over medium2195by a movable carriage (not shown) of an imaging device (not shown), such as a printer, fax machine, or the like.

FIG. 22illustrates a fluid-deposition system2200, e.g., an ink deposition system, according to another embodiment of the present invention. For one embodiment, fluid-deposition system2200includes fluid-ejection devices2210and2220, e.g., print heads, connected to a manifold2230. For another embodiment, each of fluid-ejection devices2210and2220is constructed according to the present invention. For other embodiments, each of fluid-ejection devices2210and2220is as described above for fluid-ejection device2130ofFIG. 21. For these embodiments, common reference numbers are used for each of fluid-ejection devices2210and2220and fluid-ejection device2130ofFIG. 21.

For one embodiment, manifold2230and fluid-ejection devices2210and2220are disposed on a movable carriage (not shown) of an imaging device (not shown), such as a printer, fax machine, or the like, while fluid reservoir2250is fixed to the imaging device remotely to manifold2230and fluid-ejection devices2210and2220. For another embodiment, fluid-ejection devices2210and2220are fluidly coupled directly to manifold2230without using ducts2215and2225. Specifically, fluid-ejection devices2210and2220are respectively fluidly coupled directly to internal channels2232and2234by manifolds2120of each of fluid-ejection devices2210and2220.

During operation, for one embodiment, fluid droplets2190, e.g., ink droplets, are deposited onto a medium2260, e.g., paper, by fluid-ejection device2210and/or fluid-ejection device2220as fluid-ejection devices2210and2220are carried over medium2260by the movable carriage, while fluid reservoir2250remains stationary. For this embodiment, ducts2240and2245are flexible so as to enable fluid-ejection devices2210and2220to move relative to fluid reservoir2250.

For another embodiment, manifold2230is fluidly coupled directly to fluid reservoir2250without using ducts2240and2245. For this embodiment, fluid-ejection devices2210and2220are disposed on the movable carriage of the imaging device, while fluid reservoir2250and manifold2230are fixed to the imaging device remotely to fluid-ejection devices2210and2220. For other embodiments, fluid reservoir2250delivers black ink to fluid-ejection device2210and colored ink to fluid-ejection device2220.

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