A multi-fluid body and an ejection head substrate connected in fluid flow communication with the multi-fluid body for ejecting multiple fluids therefrom. The multi-fluid body includes at least two segregated fluid chambers. Independent fluid supply paths lead from each of the fluid chambers providing fluid to multiple fluid flow paths in the ejection head substrate. The ejection head substrate is attached adjacent an ejection head area of the body. The fluid flow paths in the ejection head substrate have a flow path density of greater than about one flow paths per millimeter.

FIELD OF THE DISCLOSURE

The disclosure relates to micro-fluid ejection devices and in particular to structures and techniques for supplying multiple fluids to a multi-fluid ejection head from a multi-fluid reservoir.

BACKGROUND

In the field of micro-fluid ejection devices, ink jet printers are an exemplary application where miniaturization continues to be pursued. However, as micro-fluid ejection devices get smaller, there is an increasing need for unique designs and improved production techniques to achieve the miniaturization goals. For example, the increasing demand of putting more colors in a single ink jet cartridge requires the addition of fluid flow passageways from the cartridge body to the ejection head that, without radical changes in production techniques, will require larger ejection head substrates. However, the trend is to further miniaturize the ejection devices and thus provide smaller ejection head substrates. An advantage of smaller ejection head substrates is a reduction in material cost for the ejection heads. However, this trend leads to challenges relating to manufacturing techniques typically used for making such devices.

As the ejection heads are reduced in size, it becomes increasingly difficult to adequately segregate multiple fluids in the cartridges from one another yet provide the fluids to different areas of the ejection heads. One of the limits on spacing of fluid passageways in the ejection head substrate is an ability to provide correspondingly small, and closely-spaced passageways from the fluid reservoir to the ejection head substrate. Another limit on fluid passageway spacing is the ability to adequately align the passageways in the fluid reservoir with the passageways in the ejection head substrate so that the passageways are not partially or fully blocked by an adhesive used to attach to the ejection head to the reservoir.

Thus, there continues to be a need for improved structures and manufacturing techniques for multi-fluid reservoirs and ejection head components for ejecting multiple fluids onto a medium.

SUMMARY

With regard to the foregoing, the disclosure provides a multi-fluid body and an ejection head substrate connected in fluid flow communication with the multi-fluid body for ejecting multiple fluids therefrom. The multi-fluid body includes at least two segregated fluid chambers. Independent fluid supply paths lead from each of the fluid chambers providing fluid to multiple fluid flow paths in the ejection head substrate. The ejection head substrate is attached adjacent an ejection head area of the body. The fluid flow paths in the ejection head substrate have a flow path density of greater than about one flow paths per millimeter.

In a second embodiment, the disclosure provides a method for making a micro-fluid ejection device containing a micro-fluid ejection head for ejecting multiple-fluids therefrom. The method includes providing a multi-fluid body for ejecting multiple fluids onto a medium. The body includes a body structure having exterior side walls and a bottom wall forming an open-topped, interior cavity; an ejection head area disposed adjacent a portion of the bottom wall opposite the interior cavity; at least two segregated fluid chambers within the interior cavity of the body; and independent fluid supply paths extending from each of the fluid chambers to the ejection head area of the body. The ejection head containing an ejection head substrate is attached to the ejection head area of the multi-fluid body. The ejection head substrate contains fluid flow paths therein corresponding to the fluid supply paths in the body, wherein the fluid flow paths in the ejection head substrate have a flow path density of greater than about 1.00 flow paths per millimeter.

An important advantage of certain embodiments disclosed herein is that multiple different fluids can be ejected from a micro-fluid ejection device that is less costly to manufacture and has dimensions that enable increased miniaturization of operative parts of the device. Continued miniaturization of the operative parts enables micro-fluid ejection devices to be used in a wider variety of applications. Such miniaturization also enables the production of ejection devices, such as printers, having smaller footprints without sacrificing print quality or print speed. The apparatus and methods described herein are particularly important for reducing the size of a silicon substrate used in such micro-fluid ejection devices without sacrificing the ability to suitably eject multiple different fluids from the ejection device.

DETAILED DESCRIPTION

With reference toFIGS. 1-4, a multi-fluid body10for a micro-fluid ejection device, such as an ink jet printer12is illustrated. The multi-fluid body10includes a body structure14having exterior side walls16,18,20, and22and a bottom wall24forming an open-topped, interior cavity26. An ejection head area28is disposed adjacent a portion30of the bottom wall24opposite the interior cavity26. At least two segregated fluid chambers32and34are provided within the interior cavity26of the body10. A dividing wall36separates chamber32from chamber34. An additional dividing wall38may be provided to separate chamber40from chamber32for a body10containing three different fluids. Independent fluid supply paths are provided from each of the fluid chambers32,34, and40to provide fluid to an ejection head attached to the ejection head area28of the body10.

The body structure12is preferably molded as a unitary piece in a thermoplastic molding process. The body structure12is preferably made of a polymeric material selected from the group consisting of glass-filled polybutylene terephthalate available from G.E. Plastics of Huntersville, N.C. under the trade name VALOX 855, amorphous thermoplastic polyetherimide available from G.E. Plastics under the trade name ULTEM 1010, glass-filled thermoplastic polyethylene terephthalate resin available from E. I. du Pont de Nemours and Company of Wilmington, Del. under the trade name RYNITE, syndiotactic polystyrene containing glass fiber available from Dow Chemical Company of Midland, Mich. under the trade name QUESTRA, polyphenylene ether/polystyrene alloy resin available from G.E. Plastics under the trade names NORYL SE1, NORYL 300X, NORYL N1250, NORYL N1251, and polyamide/poly-phenylene ether alloy resin available from G.E. Plastics under the trade name NORYL GTX. A preferred material for making the body structure12is NORYL N1250 or NORYL N1251 resin.

Providing two or more chambers32,34, and40in a single body10increases the technical difficulties of using an injection molding process for making the body10. If the body10is to be molded from a polymeric material as a single molded unit, there are significant challenges to molding suitable fluid supply paths in the body10to the ejection head area28using conventional mold construction and molding techniques. Such challenges include, but are not limited to, the complexity of cooling and filling the mold used for the injection molding process.

Another multi-fluid body50is illustrated inFIG. 5. The body50illustrated inFIG. 5contains three separate fluid chambers52,56, and58for three independently supplied fluids to an ejection head60. Dividing walls62, and64are provided in the body50to isolate chambers52,56, and58from each other for providing three different fluids to the ejection head60. The fluids are retained in the chambers52,56, and58by a cover66attached to the fluid body50.

The ejection head60contains fluid ejection actuators such as heater resistors or piezoelectric devices to eject fluid from the ejection head60. Fluid to the actuators is provided from the body50through corresponding fluid flow paths68in the ejection head60. A flexible circuit70containing electrical contacts72thereon is provided and attached to the ejection head60and body50to provide electrical energy to the actuators when the body10or50is attached to an ejection device such as ink jet printer12.

A typical fluid ejection head60is illustrated inFIG. 6. InFIG. 6, the fluid ejection head60contains a thermal fluid ejection device76. The head60includes a semiconductor substrate78containing multiple conductive, insulative, and protective layers80for forming and protecting the fluid ejection device76. A nozzle plate82containing a nozzle hole84is attached to the substrate78and layers80to provide a fluid ejection chamber86. Fluid flows to the fluid ejection chamber86through a fluid supply channel88that is in flow communication with the fluid flow paths68in the head60.

As the number of fluid supply paths42,44, and46in the body10and fluid flow paths68in the head60increase, it becomes increasingly difficult to align and attach the ejection head60to the ejection head area28of the body10while increasing the number of fluid flow paths68per width W of the ejection head60(FIG. 7).

By way of further background, reference is made toFIG. 8which illustrates a prior art device made using a conventional method for forming fluid supply paths42,44and46in the ejection head area28of a multi-fluid body10.FIG. 8shows a cross section of a typical conventional ejection head area28with removable core pins90A-90B,92A-92B, and94A-94B used during a molding process for the body10to create fluid supply paths42,44, and46in the body10. Each of the core pins is provided by A and B sections that are inserted and removed from opposite sides of the body10. The core pins90A-90B,92A-92B, and94A-94B necessarily have a size sufficient to survive the molding process. Likewise, spacings96and98between the pins90A-90B,92A-92B, and94A-94B must be wide enough to allow plastic to flow. The limitations of the core pin size and the spacings96and98directly impact the ability to reduce the spacing between adjacent supply paths42,44, and46. Because the supply paths42,44, and46must align with the fluid flow paths68in the ejection head60, the foregoing limitations also directly impact the minimum size of an ejection head60made by conventional techniques.

In order for the fluid supply paths42,44, and46to be moved closer together, the core pins90A-90B,92A-92B, and94A-94B would necessarily have to be substantially smaller. However, smaller core pins90A-90B,92A-92B, and94A-94B are less able to survive a molding process as they would be too weak to be suitably removed from the molded body10.

A method according to the disclosure for providing more closely spaced fluid supply paths while providing suitable flow of polymer between the supply paths is illustrated inFIGS. 9-12. According to the illustrated method, a core pin100provides partial forming of the fluid supply path102in the body10. The core pin100is removed from the body10after molding and a secondary micro-machining operation104is conducted as shown inFIGS. 10 and 11to complete the fluid supply path102in the body10. The micro-machining operation104opens the fluid supply path102from the ejection head area28side of the body10to mate up with the partially formed supply path102created by the core pins100. As shown inFIG. 12, the fluid supply path102and fluid supply paths106and108may be made smaller and located closer together than the fluid supply paths42,44and46made by conventional techniques (FIG. 8). In the two step process illustrated inFIGS. 9-11, the core pins100are removed so that the pins100are not damaged by the micro-machining process104.

Suitable micro-machining processes104include, but are not limited to laser ablation, laser cutting, grit blast, water jet, milling, or punching. Of the foregoing procedures, laser ablation is preferred due to an ability to more precisely control the location and dimensions of the fluid paths102. The shape and size of the opening110on the ejection head area28side of the body10is determined by a mask which is accurate to less than a micron. The depth of ablation is also very controllable and less debris is present than with a process such as grit blast.

Virtually all types of polymers absorb UV laser energy in the range of about 100 to about 300 nanometers and thus may be ablated with this method. Currently features are ablated in polyimides in the micron range. Accordingly, a fluid supply path that could not be molded smaller than 400 or 500 μm through normal molding steps may be ablated in a polymeric material at a dimension or opening size of less than 10 μm. A micro-machining process104such as laser ablation enables a reduction in the ejection head60size that mates to the fluid supply paths102,106, and108in the body. A reduction in the ejection head60size reduces the size of semiconductor substrate78needed thereby lowering the overall cost of the ejection head60. Depending on the desired surface energy of the ablated fluid supply paths102,106and108in the body10, a plasma process may be implemented after the laser ablation step to further improve fluid wetting in the supply paths102,106, and108.

FIGS. 13 and 14are top plan views from the ejection head area28side of the body10illustrating the location of core pins100for forming fluid supply paths102,106, and108in the body10. InFIG. 13, the core pins100do not extend all of the way through the body10and thus the upper portion of the core pins100are illustrated by dashed lines112. InFIG. 14, the core pins100have been removed and the fluid supply paths102,106, and108are opened up from the ejection head area28side of the body10by ablating the area enclosed by the solid lines as described above.FIG. 15is a top plan view from the ejection head area28side of the ejection head60showing the substrate78containing fluid flow paths114,116, and118therein corresponding to the fluid supply paths102,106, and108superposed on the body10.

By using a two-step process to form the fluid supply paths102,106,108in the body10that will align with the fluid flow paths114,116,118in the substrate78, a body and corresponding ejection head having a much higher fluid path packing density can be provided. The number of fluid supply paths within a given linear dimension is defined as the flow path density.FIGS. 16 and 17illustrate the improvement in fluid supply path density. InFIG. 16, the length W1is 3.4 millimeters and fluid supply path42has a minimum width W2of about 0.80 millimeters. Each of the fluid supply paths44and46has a minimum width W3of about 0.66 millimeters, thus giving a fluid supply path density of about 0.87 flow paths per millimeter for three fluid supply paths over the length W1. InFIG. 17, the width W4ranges from about 0.35 to about 2.0 millimeters. Each of the fluid supply paths102,106, and108has a minimum width W5ranging from about 0.05 to about 0.4 millimeters, thus giving a fluid supply path density ranging from greater than 1.00 flow paths per millimeter up to about 3.0 flow paths per millimeter. Accordingly, the foregoing embodiment enables the fluid flow paths density in the ejection device to be increased above about 1.00 flow paths per millimeter.

In an alternative design, a body having a stepped fluid supply path design is illustrated inFIG. 18. In this case, fluid supply paths122and126have an entrance width W6and an exit width W7. The variable width of the fluid supply paths122and126reduce the contact area for an adhesive128between the body10and the substrate78allowing the fluid flow paths68on the substrate78to be placed closer together. Accordingly, the fluid flow paths68on the substrate are provided within a width of W8that is substantially less than the width W1to provide a fluid flow path density ranging from greater than about 1.00 mm−1up to about 3.0 mm−1.

Improved materials and molding technology enable molding fluid supply paths in a body as described above with reference toFIG. 17or18. In order to increase the density of the fluid supply paths102,106, and108, the walls109and111between the supply paths should be made as narrow as possible while still providing sufficient surface area for adhesively attaching the substrate78to a body113(FIG. 17). Accordingly, the minimum wall width preferably ranges from about 0.15 to about 0.25 millimeters. For molding purposes, a polyethylene terephthalate material may provide sufficient mold filling and mechanical properties for the walls.

In another embodiment of the disclosure, the fluid flow path density of the ejection head68may be increased by altering the fluid flow paths through the substrate. Typically, fluid flow paths130in the substrate132are elongate, narrow slots that are formed through the thickness of the substrate132, as seen in the prior art devices ofFIGS. 19-20. Accordingly, body134of the prior art device ofFIG. 21contains corresponding elongate openings or fluid supply paths136therein for flow of fluid from chambers32,38, and40. However, as set forth above, it is difficult to mold the body134to conform to the slot spacing of the substrate132.

In another embodiment, a substrate is modified to enable easier molding of a fluid reservoir body to conform to the spacing of slots in the substrate. According to this embodiment, fluid flow paths138in a substrate140are formed using a two-step etching process to provide a substrate as illustrated inFIGS. 22-23B. According to the process, short, a portion of relatively wide slots142,144, and146are cut or etched all the way through the substrate140at one end of the fluid flow paths138from a first side148thereof.

In one embodiment, a deep reactive ion etching (DRIE) process is used to etch the slots142-146. Using DRIE, for example, can provide slots having relatively parallel (as opposed to angled) side walls.

In one embodiment, at least one of the short slots142,144, and146is staggered with respect to the other short slots In certain embodiments, this may allow for the use of less substrate area. For example, staggering short slot142with respect to short slots144and146enables the short slots to be positioned in such a way that the combined width of the short slots142,144, and146is greater than a separation distance between respective outermost edges of short slots144and146. Such a configuration of short slots142-146may provide for the use of a relatively narrower substrate140while still providing adequate surface area for adhesive application.

Full-length slots152are cut or etched half way through the thickness of the substrate140from either the first side148or from a second opposite side150of the substrate140. The full length slots152intersect the short slots142,144, and146to provide fluid flow paths138through the substrate140as indicated by arrow154.

The openings142,144, and146have substantially the same open area as openings152, however the openings142-146have a wider rectangular configuration as compared to the openings152. The openings142-146on the first side148of the substrate140enable similarly shaped fluid supply paths156to be provided in a fluid reservoir158(FIG. 24). Because the fluid supply paths156in the reservoir158may be spaced closer together, the substrate140attached to the reservoir158may be provided with a smaller width and have a higher density of fluid flow paths138per width as described above. Accordingly, the substrate140width may be decreased from about 500 to about 700 microns, or more, using the embodiments described above. The foregoing arrangement of fluid flow paths138also provides an increased area for attaching and sealing the substrate140adjacent the fluid reservoir body158.

Another slot arrangement that may be used to increase a distance between adjacent fluid flow paths160on a first side162of a substrate164is illustrated inFIGS. 25 and 26. Flow paths160in the substrate164are provided by an offset double side cut etch through portions of the substrate164as shown inFIG. 26. In this embodiment, first portions166of the flow paths160on the first side162of the substrate164are cut or etched two thirds of the way through the substrate164. Second portions168of the flow paths160are cut or etched two thirds of the way through the substrate164from a second side170thereof. The first and second portions166and168are offset by nearly the flow path width PW. The two portions166and168intersect part way through the substrate164to provide a through passage for fluid in the substrate164. Like the previous embodiment, this embodiment increases the width between the flow paths160on the fist side162of the substrate164by as much as two flow path widths PW, thereby providing an increased area for attaching and sealing the substrate164adjacent a fluid reservoir body.

In another embodiment, the substrate184may have angled flow paths186through the thickness of the substrate184so that the flow paths on one side of the substrate184are spaced farther apart than the flow paths on an opposite side of the substrate as shown inFIG. 27. Typically, flow paths186A on a body side188of the substrate184will be spaced farther apart than flow paths186B on a nozzle plate side190of the substrate184.

An increase in flexibility of design for smaller substrates may also be provided by use of one or more of the following embodiments incorporating a manifold structure. An illustration of a multi-fluid reservoir200containing a manifold202attached in a manifold pocket204of the reservoir200is illustrated inFIGS. 28-30. An adhesive206is preferably used to attach the manifold202in the manifold pocket204(FIG. 30).

As described in more detail below, the manifold202is used to create passages for the fluid from the reservoir200to a semiconductor substrate208and nozzle plate210providing the ejection head60. The manifold202eliminates numerous challenges associated with a manufacturing process and mold design for injection molding of fluid supply paths212in the reservoir200and for attaching the substrate208to the reservoir200.

Conventional attachment methods like ultrasonic welding are commonly used in industry to join polymeric components together. However, obtaining a hermetic seal with ultrasonic welding in a micro-fluid ejection system is very difficult if not impossible, due to the limitation in joint design and the uncontrollable flash generated during the welding process. In fact, debris and vibration often cause a substantial amount of yield loss. Adhesive bonding is a viable alternative for joining the manifold202to the fluid reservoir200to provide a hermetic seal between fluid supply paths212. However, the adhesive usually takes a very long time to cure at room temperature and there is a risk of blocking the supply paths212due to the spreading of the adhesive into the supply paths212.

One solution to adhesive spreading for the fluid reservoir200and ejection head60for a micro-fluid ejection device is to provide the manifold202with fluid flow channels214having a spacing on a substrate side216of the manifold202closer together than a channel spacing on the fluid reservoir side218of the manifold202. In order to achieve such unequal spacing of the fluid flow channels214in the manifold202, the fluid flow channels214are not parallel but are angled and converged together moving from side218to side216of the manifold202.FIG. 30illustrates a cross-sectional view of the manifold202having the converging fluid flow channels214therein coupled to the semiconductor substrate208. With such a design, a conventional fluid supply path212spacing of the reservoir200can be used or the fluid supply paths212in the reservoir200may be made wide enough to increase the ease of molding the reservoir fluid supply paths212easier and to increase the ease of providing a hermetic seal between the manifold202and the reservoir200.

The manifold202may be made from a variety of materials that are compatible with the fluids in the reservoir200including polymers and ceramics. Accordingly, the manifold202may be molded of a material that has a coefficient of thermal expansion (CTE) close to that of the semiconductor substrate208in order to reduce thermal stresses during adhesive curing of the substrate208to the manifold202and the manifold202to the reservoir200. The manifold202may also be molded of a material that is transparent to an infrared laser beam that may be used to cure an adhesive between the substrate208and the manifold202. Laser beam radiation curing is described in more detail below. The manifold202may be molded in a material that is very tough and flexible that is suitable for reducing the chances of cracking the substrate208from a drop impact of the reservoir200or ejection head60.

For example, a ceramic manifold may be molded to contain a complex geometry and can also be modified through secondary processes, such as machining, to provide tighter tolerances and smaller features. A ceramic manifold may also be used in the same way that a plastic may be use to provide a manifold that would connect widely spaced apart fluid supply paths in a relatively cheap multi-fluid reservoir to closely spaced apart fluid flow paths in a substrate. If a tortuous path was necessary to create very complex flow features, multiple layers or plates of ceramic material may be bonded together to form such features. Reducing the limitations of a structure that a semiconductor substrate is then bonded to, can provide the benefit of being able to drastically reduce the size of the semiconductor substrate.

A ceramic manifold may also provide improved stability for the semiconductor substrate by maintaining greater flatness of the substrate. When in contact with a plastic body during a heating process, the substrate and plastic body tend to expand and contract at different rates. Such expansion and contraction causes stress on the substrate and can cause the substrate to bow. Substrate bow causes fluid delivery quality problems and fragility problems. Ceramic substrates maintain a very tight tolerance on flatness prior to substrate attachment which aids the substrate bonding process. With the use of a ceramic manifold the fluid flow path density, or number of flow paths per unit area, of the semiconductor substrate can be increased

In another embodiment, a V-shaped manifold block220is provided as illustrated inFIGS. 31-33. The V-shaped manifold block220enables a multi-fluid reservoir222to be molded with a single axis slide for fluid supply paths224and keeps all intricate molding in the manifold block220. The geometry and cross section of the manifold block220and reservoir body222are illustrated inFIGS. 32 and 33. A single axis slide that forms the fluid supply paths224may be pulled from a fluid exit side of the reservoir222thereby minimizing mold complexity. The manifold block220may be molded with simple side pulls.

The next manifold embodiment includes a thin manifold plate228that is attached directly to the semiconductor substrate208by use of an adhesive. The manifold plate228, has a design feature in such a way that each fluid flow channel230has a relatively narrow end232and relatively wide end234as illustrated inFIG. 34. Each wide end234has a passages through the thickness of the manifold plate228whereas the narrow end232only extends partially through the thickness of the plate228. Adjacent fluid flow channels230are oriented such that the wide ends234that connect to fluid supply paths in the fluid reservoir are spaced apart as generally described above with reference toFIG. 26. The foregoing manifold plate228design enables a spacing between fluid flow paths238in the substrate208to be reduced by ⅓ as compared to the spacing of fluid flow paths130in a conventional substrate132as illustrated inFIG. 19.

The manifold plate228may be fabricated by laser ablation, deep reactive ion etching (DRIE), or the plate228may be micro-molded to provide the flow channels230therein. The manifold pate228may be compression bonded to the substrate208at the same time that a nozzle plate210(FIG. 28) is compression bonded to the substrate208. Bonding of the manifold plate228to a semiconductor substrate208may be done while the substrate208is still part of a silicon wafer, prior to dicing to wafer to provide individual substrates208.

As shown inFIG. 35, the foregoing manifold plate228enables a larger adhesive sealing area between fluid supply paths240on a reservoir body than a conventional design as shown inFIG. 36. The wide ends234of the fluid flow channels230have a large enough cross-sectional area so as not restrict fluid flow from the fluid reservoir. Accordingly, it is easier to apply an adhesive242to seal the plate228to the reservoir than an adhesive244used to seal a substrate to a reservoir in the conventional fluid flow path136design (FIG. 35).

In order to attach the manifold202,220, or228to the corresponding body200,222, or182, a non-contact laser welding technique is preferably used because of the substantial high precision requirement for miniature features. Mask transmission laser welding is a precision welding technology developed by Leister Technologies. A line-shaped laser beam, is moved across the parts to be welded. The laser beam can reach the parts everywhere a weld line is desired, but is blocked in the other places by a mask placed between the parts and the laser. Mask laser welding may be used for welding together polymeric parts, which enables placing very precise and fine weld lines (less than 0.2 mm), on components to be welded. Such fine weld lines cannot be effectively achieved with conventional welding or bonding methods.

Other laser transmission welding methods that may be used to seal a manifold202,220, or228to its corresponding body200,222, or182include, but are not limited to fiber optics/waveguide based simultaneous welding or scanning type ND:YAG laser welding driven by two rotating mirrors. The fine weld lines provided by a laser welding process are able to provide a hermetic seal between flow paths and flow channels. However, the bond lines are fragile and the mechanical strength may not be strong enough to hold the manifold202,220, or228to the body200,222, or182because of the micro-sized weld lines. Therefore, auxiliary weld points are preferably provided to strengthen the joint and the miniature seal.

Auxiliary weld points may be provided as by use of heat staking. Heat staking is an assembly method that uses controlled melting and forming of a boss or stud to capture or lock another component in place. With reference toFIGS. 37 and 38, a suitable heat staking process is illustrated. According to the process, a stud246is made of a plastic or polymeric material. A hot iron248contacts the stud246and melts an end thereof to provide a stud head250that is wider than an opening252in the manifold through which the stud246extends. The stud head250is preferably recessed in a recessed area254of the manifold220so that the stud head250does not interfere with the head60attached to the manifold220. With the combination of laser welding and heat staking in one process, the seal and the joint256between the manifold220and the body222are strong and durable.

Another method to create a micro-seal between adjacent fluid supply paths212in the body200and fluid flow paths236in a semiconductor substrate208that are closely spaced apart is to use a die cut adhesive gasket260instead of dispensing an adhesive bead to seal between the adjacent flow paths236. The geometry of a die cut adhesive260can be controlled more precisely than dispensing an adhesive bead because its shape may be cold formed. A preferred die cut adhesive260is a thermally activatable, low melt adhesive that is compatible with the fluids in the body200, such as ink. The die cut adhesive260may include a liner on one surface262thereof to aid in apply the adhesive260to the body200. It will be appreciated that the die cut adhesive260may also be used to attach the substrate208to a manifold such as manifold202,220, or228.

As shown inFIG. 40, the current die bond area264of the multi-fluid semiconductor substrate78for use in an ink jet printer, is around 0.6 mm in width. With the introduction of a separate manifold202,220, or228, as described above, the die bond area264can be reduced to 0.1 mm. Materials that may be used as manifold materials for such applications include a styrene butadiene copolymer (SBC), polyphenylene ether/polystyrene alloy (PPE/PS), or a general purpose polystyrene (GPPS), which are transparent to infrared radiation and are also chemically compatible with the body material (i.e., NORYL N1250, NORYL N1251 for example) describe above. In the alternative, the manifold may be made of a thermoplastic polyester resin available from GE Plastics under the trade name VALOX. When a VALOX resin is used for the manifold, the body material is also preferably made of a polyester resin. When the die bond area264becomes smaller and smaller, precision alignment of the paths and/or channels is crucial.

Conventional adhesive266bonding will not give the placement accuracy required as the whole thermal mass is put inside an oven for curing at an elevated temperature. The thermal process typically results in part dislocation after cooling. On the other hand, the heat deflection temperature (HDT) of the body material must be higher than the baking temperature to avoid thermal deflection and deformation of the fluid supply paths42,44and46in the body10. Such requirement limits the choice of acceptable body materials. Thermal stress developed in the adhesive266area will also reduce the corrosion resistance of the structure.

In order to overcome the above problems and to bond the substrate208to the manifold202or body200, localized or preferential heating may be used to cure the die bond adhesive266. Since the manifold202is made of a material that is typically selected to be transparent to a laser beam268from a laser beam source270, the manifold202can be used directly as a light transfer media (waveguide) to guide the infrared or laser beam268to the adhesive266. In this way, heating is rapid and is localized and the adhesive266may be cured in minutes. The problems associated with die bond wicking into the flow paths68and flow channels216can be minimized because of the rapid curing of the adhesive266. In addition, thermal stresses developed in the adhesive266area may be reduced.FIG. 41illustrates use of rapid curing of an adhesive266with a laser beam268by use of a manifold202to guide the laser beam268to the adhesive266.

When266adhesive is continuously exposed to infrared or laser radiation, overshooting of the adhesive may occur which damage intrinsic properties of the adhesive266. In order to keep the adhesive266at any desired temperature for curing, pulse heating is may be used. An advantage of using pulse heating as opposed to continuous heating may be to enable time for the adhesive266to conduct heat to the substrate78. When the heat generated in the adhesive266by infrared radiation equals the heat dissipated to the surrounding material78, temperature of the adhesive266will reach an equilibrium level. Adjusting the frequency of the pulse, the pulse length, and the infrared/laser power, will provide a desired temperature for curing the adhesive266.

In another embodiment, the manifold202is not transparent to laser or infrared radiation. In this embodiment, illustrated inFIG. 42, a fiber optic tool or wave guide272that fits through the channels216in the manifold202is used to direct the infrared laser or ultra violet (UV) light beams into the die bond adhesive266for rapid curing of the adhesive. The adhesive266may be either UV activated or thermal activated by infrared radiation.

The use of a manifold structure as describe above enables other variations in fluid reservoir design as illustrated inFIGS. 43-45. InFIG. 43, instead of a single multi-compartmentalized body, individual fluid containers such as fluid containers300and302are provided. The fluid containers300and302have fluid cavities304and306for different fluids. The fluid cavities are closed by covers308and310. A fluid outlet port312,314is provided for each container300,302. The containers300,302are inserted into a container housing316that contains a standpipe assembly318for fluidly coupling the outlet ports312,314of the containers300,302to a manifold320. The outlet ports312,314of the containers300,302are fluidly coupled to the standpipe assembly318when the containers300,302are disposed in the container housing316.

The manifold320is shown in detail inFIG. 44. It is preferred that the manifold320and standpipe assembly318be made of the same or similar material, with at least one of the materials being translucent to laser radiation to enable laser welding of one component to the other. Micro molding techniques may be used to mold grooves and slots322in the manifold320. The manifold320may be made of an engineered plastic which results in an as-molded flatness of about 0.02 mm. The engineered plastic preferably has a low thermal coefficient of expansion, a high deflection temperature (HDT), a high mechanical strength, and is transparent to laser radiation.

In the manifold illustrated inFIG. 44, the standpipe assembly318fluidly connects with inlet ports324,326,328, and330. Each of the inlet ports324and326feed separate flow channels332and334respectively. Inlet ports328and330may also feed separate flow channels, or as illustrate, may feed a common flow channel336. It will be appreciated that more than three flow channels332,334, and336may be provided in the manifold with a corresponding number of inlet ports. For example, as shown inFIG. 45, manifold338contains eight flow channels340fed by eight corresponding inlet ports342. As above, the inlet ports342are fluidly connected to a standpipe assembly for flow of different fluids from fluid reservoirs to through the manifold336and to an attached semiconductor substrate for ejecting the fluids.

It is contemplated, and will be apparent to those skilled in the art from the preceding description and the accompanying drawings, that modifications and changes may be made in the embodiments of the invention. Accordingly, it is expressly intended that the foregoing description and the accompanying drawings are illustrative of preferred embodiments only, not limiting thereto, and that the true spirit and scope of the present invention be determined by reference to the appended claims.