Fluid ejection cartridge including a compliant filter

Information

  • Patent Grant
  • 6702436
  • Patent Number
    6,702,436
  • Date Filed
    Wednesday, January 30, 2002
    22 years ago
  • Date Issued
    Tuesday, March 9, 2004
    20 years ago
Abstract
A fluid ejection cartridge includes a fluid container that has both a fluid inlet and a fluid outlet. The fluid ejection cartridge has one or more fluid ejectors fluidically coupled to the fluid container outlet and a fluid valve fluidically coupled to the fluid container inlet. The fluid ejection cartridge has a filter assembly having a compliant portion with an internal volume fluidically coupled to the fluid container outlet such that the internal volume changes when fluid flows into the fluid container.
Description




BACKGROUND




DESCRIPTION OF THE ART




Over the past decade, substantial developments have been made in the micro-manipulation of fluids in fields such as electronic printing technology using inkjet printers. As the volume of fluid manipulated or ejected decreases the susceptibility to clogging of fluid channels and nozzles has increased. Fluid ejection cartridges provide a good example of the problems facing the practitioner in preventing the clogging of microfluidic channels and nozzles due to particulates.




Fluid ejection cartridges typically include a fluid reservoir that is fluidically coupled to a substrate that is attached to the back of a nozzle layer containing one or more nozzles through which fluid is ejected. The substrate normally contains an energy-generating element that generates the force necessary for ejecting the fluid held in the reservoir. Two widely used energy generating elements are thermal resistors and piezoelectric elements. The former rapidly heats a component in the fluid above its boiling point causing ejection of a drop of the fluid. The latter utilizes a voltage pulse to generate a compressive force on the fluid resulting in ejection of a drop of the fluid.




Currently there is a wide variety of highly-efficient inkjet printing systems in use, which are capable of dispensing ink in a rapid and accurate manner. However, there is a demand by consumers for ever-increasing improvements in speed and image quality. To improve image quality, the size or diameter of each nozzle typically decreases. For example, today printers generally have 300 to 600 dpi (dots per inch). In order to improve print speed the number of nozzles necessarily increases. Thus, improvements in both image quality and speed have led to a decrease in the size of the nozzles as well as an increase in the number of nozzles on a printhead. This utilization of a greater number of smaller nozzles has created a greater degree of susceptibility to plugging from particulates in the ink supply. The plugging of a nozzle results in serious degradation of the image or print quality of the printer system.




In order to prevent the nozzle system from becoming clogged with particulate matter, a mechanical filter element is typically disposed in the ink jet print cartridge such that the ink is filtered before it is supplied to the nozzle system. If the ink is not filtered it would tend to clog or block the nozzles. These mechanical filters are generally screens and typically made of stainless steel woven mesh. They are attached to what is generally referred to as a standpipe. The standpipe provides fluid communication between the ink reservoir of the print cartridge and the fluid ejectors. This mesh is typically rigidly secured around the edges to the standpipe to prevent leakage of ink around the filter element.




In addition, in an effort to reduce the cost and size of ink jet printers and to reduce the cost per printed page, printers have been developed having small, moving printheads that are connected to large stationary ink supplies. This development is called “off-axis” printing and has allowed the large ink supplies to be replaced as it is consumed without requiring the frequent replacement of the costly printhead containing the fluid ejectors and nozzle system. However, the typical “off-axis” system requires numerous flow restrictions between the ink supply and the printhead, such as additional orifices, long narrow conduits, and shut off valves. To overcome these flow restrictions and to also provide ink over a wide range of printing speeds, ink is now transported to the printhead at an elevated pressure. A pressure regulator is typically added to deliver the ink to the printhead at the optimum backpressure.




Further, an “off-axis” printing system strives to maintain the back pressure of the ink within the printhead to within as small a range as possible. Changes in back pressure greatly affect print density as well as print and image quality. In addition changes in back pressure can cause either the ink to drool out of the nozzles or to deprime the printhead. As consumer demands push the technology to ever smaller nozzles it becomes necessary to filter ever smaller particles from the ink. However, mechanical filter elements capable of filtering smaller particles typically require a larger pressure drop across the filter medium to generate the same flow rate as a larger particle filter. Thus, the requirement to filter smaller particles yet maintain the back pressure of the ink within the printhead to within as small a range as possible has produced a problem in inkjet technology development.




SUMMARY OF THE INVENTION




A fluid ejection cartridge includes a fluid container that has both a fluid inlet and a fluid outlet. The fluid ejection cartridge has one or more fluid ejectors fluidically coupled to the fluid container outlet and a fluid valve fluidically coupled to the fluid container inlet. The fluid ejection cartridge has a filter assembly having a compliant portion with an internal volume fluidically coupled to the fluid container outlet such that the internal volume changes when fluid flows into the fluid container.











BRIEF DESCRIPTION OF THE DRAWINGS





FIG. 1

is a block diagram of a fluid ejection cartridge according to an embodiment of the present invention;





FIG. 2



a


is graph of pressure as a function of time in a fluid ejection cartridge according to an embodiment of the present invention;





FIG. 2



b


is graph of pressure as a function of time in a fluid ejection cartridge according to an embodiment of the present invention;





FIG. 3



a


is a perspective view of a fluid ejection cartridge according to an embodiment of the present invention;





FIG. 3



b


is a plan view of a filter assembly according to an embodiment of the present invention;





FIG. 3



c


is a cross-sectional view of a filter assembly according to an embodiment of the present invention;





FIG. 3



d


is a cross-sectional view of a filter assembly according to an embodiment of the present invention;





FIG. 4

is a perspective view of a fluid ejection system according to an embodiment of the present invention;





FIG. 5



a


is a cross-sectional view of a fluid ejection cartridge according to an embodiment of the present invention;





FIG. 5



b


is a cross-sectional view of a fluid ejection cartridge according to an embodiment of the present invention;





FIG. 6



a


is a cross-sectional view of a filter assembly according to an embodiment of the present invention;





FIG. 6



b


is a cross-sectional view of a filter assembly according to an embodiment of the present invention;





FIG. 7



a


is a cross-sectional view of a filter assembly according to an embodiment of the present invention;





FIG. 7



b


is a cross-sectional view of a filter assembly according to an embodiment of the present invention.











DETAILED DESCRIPTION OF THE INVENTION




Referring to

FIG. 1

, an embodiment of fluid ejection cartridge


100


of the present invention in a simplified block diagram is shown. In this embodiment, filter assembly


120


includes compliant portion


140


and non-complaint portion


130


disposed in fluid container


110


. However, depending on the particular application in which fluid ejection cartridge


110


will be used, filter assembly


120


may also be located outside of fluid container


110


, such as between fluid container


110


and fluid outlet


154


. Fluid inlet


150


is fluidically coupled to fluid container


110


so that when fluid regulator


152


or regulator is in an open state fluid can flow from a fluid supply (not shown) into fluid container


110


. Fluid in container


110


flows through filter assembly


120


through fluid outlet


154


to fluid ejector


156


, as fluid is ejected from fluid ejection cartridge


100


through one or more nozzles (not shown) by activating fluid ejector


156


. When fluid regulator


152


causes additional fluid to flow into fluid container


110


, compliant portion


140


of filter assembly


120


responds to changes in pressure, thereby dampening pressure transients created by the opening of the valve typical of most valves used as fluid regulator


152


.




Many fluid ejection delivery systems strive to keep the pressure of the fluid within fluid ejection cartridge


100


constant. Fluid flow is generally controlled by a fluid delivery system. The fluid delivery system regulates the pressure of the local fluid supply within fluid ejection cartridge


100


to a pressure less than ambient, which is generally referred to as backpressure. The backpressure range is controlled to keep the backpressure from affecting the ejecting frequency and amount of fluid ejected out of fluid ejection cartridge


100


. If the backpressure is equal to or greater than ambient pressure, fluid will leak or drool out of the one or more nozzles. If the backpressure is much less than ambient pressure, the nozzles and area around fluid ejector


156


will not properly refill. Typical fluid ejection cartridges utilize a regulator to control the backpressure over a range of fluid flow rates. The particular pressure and flow rates depend on the particular application of the fluid ejection cartridge.




The transient pressure response at a fixed flow rate for a typical regulator coupled to a fluid ejection cartridge having a non-compliant filter is shown graphically in

FIG. 2



a


. The bottom curve represents the transient pressure response of the filter, where the rising edge at the left side signifies the fluid ejector turning on and the peak indicates the start of fluid flow into the fluid container. The falling edge at the right side signifies the fluid ejector shutting off stopping fluid flow. The middle curve represents the transient pressure response of fluid container


110


, where the peak on the left side indicates that the backpressure within fluid container


110


exceeds the steady state pressure for a short period of time. When fluid stops flowing as depicted on the right side of the middle curve the backpressure undershoots the steady state pressure of fluid ejection cartridge


100


. The top curve represents the transient pressure response in the vicinity of fluid ejector


156


where the peak on the left side indicates that the backpressure exceeds the steady state backpressure for a short period of time at fluid ejector


156


resulting in a pressure spike. Thus, the fluid ejector pressure represents, for a system utilizing a non-compliant filter, the combined effect of the transient pressure response of the filter and the fluid container


110


. In the interval while the backpressure at fluid ejector


156


exceeds a predetermined value the drop size or amount of the fluid ejected will vary from its steady state value.




The transient pressure response at a fixed flow rate for a typical regulator coupled to a fluid ejection cartridge having a compliant filter portion is shown graphically in

FIG. 2



b


. The bottom curve represents the transient pressure response of the filter, where the rising edge on the left side, again signifies the fluid ejector turning on starting fluid flow. However, unlike a non-complaint filter, the internal volume of compliant portion


140


of filter assembly


120


decreases, in response to the flow transient, providing a more gradual rise in pressure. When the fluid ejector turns off, stopping fluid flow, the internal volume of compliant portion


140


increases eventually returning to substantially the same volume before filling started. This increase in volume provides a more gradual decrease in pressure as shown on the right side of the bottom curve when compared to a non-compliant filter. The middle curve represents the transient pressure response of fluid container


110


, and is substantially the same as that shown in

FIG. 2



a


for a non-compliant filter. The top curve again represents the transient pressure response in the vicinity of fluid ejector


156


. The fluid ejector pressure, again, represents the combined effect of the transient pressure response of filter assembly


120


and fluid container


110


. By utilizing compliant portion


140


, the pressure spike observed using a non-compliant filter has been attenuated. Such attenuation provides a more uniform drop size during refill.




Referring to

FIG. 3



a


an exemplary embodiment of the present invention is shown in perspective view. In this embodiment, pen body


360


forms the walls of fluid container


310


for fluid ejection cartridge


300


. Fluid ejector head


370


includes one or more fluid ejectors disposed on substrate


372


. Preferably, substrate


372


, nozzle layer


374


, nozzles (not shown), and a chamber layer (not shown) form what is generally referred to as an ejector head. However, depending on the particular application and fluid ejection properties desired, other embodiments may utilize nozzle layer


374


with flexible circuit


375


integrated to form one part. Nozzle layer


374


contains one or more nozzles (not shown) through which fluid is ejected. Flexible circuit


375


of the exemplary embodiment is a polymer film and includes electrical traces (not shown) connected to electrical contacts (not shown). The electrical traces and contacts to bond pads (not shown) on substrate


372


provide electrical connection for fluid ejection cartridge


300


. Preferably the one or more fluid ejectors are deposited onto substrate


372


using conventional semiconductor processing equipment to create the various thin films utilized in forming the fluid ejectors.




Located within pen body


360


is filter assembly


320


that is fluidically coupled to standpipe


378


via filter fitment


334


. Filter assembly


320


is shown in plan view in

FIG. 3



b


. Filter assembly


320


includes filter frame


332


that forms non-complaint portion


330


. In addition, a portion of filter frame


332


forms filter fitment


334


that is, preferably, press-fit into a mating structure in standpipe


378


. Compliant portion


340


includes filter material


342


that is, preferably, heat staked to filter frame


332


so that outer surface


341


of filter material


342


and


344


forms a convex shape. However, depending on the particular materials utilized for filter material


342


and filter frame


332


, adhesives and other mechanical fastening methods may also be utilized to attach filter material


342


to filter frame


332


.




Filter material


342


can be any of the filter materials well known in the art. The actual filter material utilized will depend both, on the particular application in which fluid ejection cartridge


300


will be utilized, as well as on characteristics or criteria of the filter material such as filtration efficiency, pressure drop, and chemical and thermal robustness to name a few. Preferably, the filter material is a polymer. However, materials woven from fibers of metal, ceramic, or glass can also be utilized. More preferably filter material


342


is a porous membrane such as polysulfone or polytetrafluoroethylene.




An exemplary filter material is a polyester/polysulfone/polyester three-layer film. The mean pore size of filter material


342


can range from about 1 micron to about 50 microns, preferably ranging from about 2 microns to about 10 microns. Typically the mean pore size is about one third the size of the smallest feature that the fluid flows through. In addition, filter material


342


exhibits a flow rate of between about 20 milliliters per min (ml/min.) to about 300 ml/min. at a pressure less than about 8 inches of water (in. H


2


O) at a viscosity of less than about 25 centipoise (cp). However, filter material


342


, preferably, exhibits flow rates of between about 40 ml/min. to about 100 ml/min. at a pressure less than about 5 in. H


2


O at a viscosity of less than about 15 cp. More preferably, filter material


342


exhibits flow rates of between about 45 ml/min. to about 55 ml/min. at a pressure less than about 2 in. H


2


O at a viscosity of less than about 5 cp.




Filter frame


332


can be formed from any of the metal, polymer or ceramic materials well known in the art. The actual frame material utilized will depend both, on the particular application in which fluid ejection cartridge


300


will be utilized, as well as on characteristics of the filter material such as the materials chemical and thermal robustness. Preferably, the frame material is a thermoplastic polymer, and more preferably an injection moldable thermoplastic polymer such as polyethylene, polypropylene or polyester to name a few.




Also located within pen body


360


is regulator


366


that includes pressure regulator lever


362


, accumulator lever


364


, and flexible bag


365


as shown in

FIG. 3



a


. Flexible bag


365


is illustrated as fully inflated in

FIG. 3



a


. Pressure regulator lever


362


and accumulator lever


364


are urged together by a spring (not shown). In opposition to the spring, flexible bag


365


spreads the two levers (


362


,


364


) apart as it inflates outward. Flexible bag


365


is staked to fitment


367


that is preferably press-fit into crown


361


. Preferably pen body


360


and crown


361


are made from a thermoplastic polymer utilizing conventional injection molding equipment. Fitment


367


includes vent


369


to ambient pressure in the shape of a helical, labyrinth path. Vent


369


connects to, and is in fluid communication with, the inside of flexible bag


365


, so that flexible bag


365


is maintained at a reference pressure. The helical path reduces the diffusion of fluid out of fluid container


310


via diffusion through flexible bag


365


.




Regulator lever


362


rotates about two opposed axles (not shown) that form the axis of rotation of regulator lever


362


. When regulator lever


362


engages filter assembly


320


the rotation of the lever is stopped. Approximately perpendicular to the plane of regulator lever


362


is a valve seat (not shown) that is formed of a resilient material. In response to the expansion or contraction of flexible bag


365


, regulator lever


362


rotates about the axles (not shown) causing the valve seat (not shown) to open and close against a mating surface on crown


361


. This rotational motion of regulator lever


362


regulates the flow of fluid into fluid container


310


via septum


351


. Accumulator lever


364


and flexible bag


365


operate together, in a similar manner as that described for regulator lever


362


, to accommodate changes in volume due to any air that may be entrapped in fluid ejection cartridge


300


, as well as due to other pressure changes, such as a change in altitude. For a more detailed description of the structure and operation of such a regulator as depicted in

FIG. 3



a


, see U.S. Pat. No. 5,872,584.




When regulator lever


362


rotates causing the valve seat to open fluid will flow through septum


351


into fluid container


310


applying a force (i.e. the back pressure of a fluid delivery system) to compliant portion


340


that includes filter material


342


. This applied force or pressure changes the substantially convex shape of outer surface


341


of filter material


342


as shown in

FIG. 3



c


to a substantially concave shape as shown in

FIG. 3



d


with a corresponding decrease in internal volume


346


of compliant portion


340


. This change in internal volume


346


of compliant portion


340


acts to provide a more gradual rise in pressure observed in the vicinity of the one or more fluid ejectors disposed on substrate


372


of fluid ejector head


370


. As fluid ejection cartridge fills with fluid, flexible bag


365


deflates urging regulator lever


362


to rotate in the opposite direction causing the valve seat to close, thereby decreasing the force or pressure of the fluid delivery system on compliant portion


340


. This decrease in pressure allows compliant portion


340


to change, from the substantially concave shape as shown in

FIG. 3



d


, to a substantially convex shape as shown in

FIG. 3



c


, with a corresponding increase in internal volume


346


of compliant portion


340


. This increase in internal volume


346


acts to provide a more gradual decrease in pressure observed in the vicinity of the fluid ejectors on substrate


372


.





FIGS. 3



a-




3




d


illustrate an exemplary embodiment where fluid flows from the outside of filter assembly


320


through filter material


342


into internal volume


346


and then through filter fitment


334


to standpipe


378


. However, fluid ejection cartridge


300


may also be constructed such that filter fitment


334


is fluidically coupled, for example, to septum


351


such that fluid flows into internal volume


346


through filter material


342


to the outside of filter assembly


320


to standpipe


378


. In the latter case filter material


342


is formed so that the applied force of the fluid flow is against the substantially convex shape of inner surface


343


of filter material


342


. In addition, the amount of deflection will depend on the elasticity of filter material


342


. To obtain a particular amount of deflection for a given applied force both the thickness as well as the height and width of filter frame


332


, to which filter material


342


is attached, may be modified. The amount of tension, including no tension, applied to filter material


342


may also be varied to further optimize the amount of deflection for a given applied force. By controlling these variables a wide variety of filter materials having a range of elasticities may be utilized. For example, compliant portion


340


may include an elastic filter material such as a woven nylon mesh.




Referring to

FIG. 4

, a perspective view is shown of an exemplary embodiment of a fluid ejection system of the present invention in. As shown printer


480


includes fluid or ink supply


486


, including one or more secondary fluid or ink reservoirs


488


that provide fluid to one or more fluid ejection cartridges


400


commonly referred to as print cartridges. Preferably, print cartridges


400


are similar to fluid ejection cartridge


300


as shown in

FIG. 3



a


, however, other fluid ejection cartridges may also be utilized. Secondary fluid reservoirs


488


are fluidically coupled to fluid ejection cartridges via flexible conduit


495


. Fluid ejection cartridges


400


may be semi-permanently or removably mounted to carriage


490


. In this embodiment, a platen or sheet advancer (not shown) to which print media


484


, such as paper, is transported by mechanisms that are known in the art. Carriage


490


is typically supported by slide bar


494


or similar mechanism within fluid ejection system


480


and physically propelled along slide bar


494


to allow carriage


490


to be translationally reciprocated or scanned back and forth across sheet


484


. Printer


480


may also employ coded strip


492


, which may be optically detected by a photodector (not shown) in carriage


490


for precise positioning of the carriage. Carriage


490


may be translated, preferably, using a stepper motor (not shown), however other drive mechanism may also be utilized. In addition, the motor may be connected to carriage


490


by a drive belt, screw drive, or other suitable mechanism.




When a printing operation is initiated, print media


484


in tray


482


is fed into a printing area (not shown) of printer


480


. Once print media


484


is properly positioned, carriage


490


may traverse print media


484


such that one or more print cartridges


400


may eject ink onto print media


484


in the proper position. Print media


484


may then be moved incrementally, so that carriage


490


may again traverse print media


484


, allowing the one or more print cartridges


400


to eject ink onto a new position on print media


484


. Typically the drops are ejected to form predetermined dot matrix patterns, forming for example images or alphanumeric characters.




Rasterization of the data can occur in a host computer such as a personal computer or PC (not shown) prior to the rasterized data being sent, along with the system control commands, to the system, although other system configurations or system architectures for the rasterization of data are possible. This operation is under control of system driver software resident in the system's computer. The system interprets the commands and rasterized data to determine which drop ejectors to fire. Thus, when a swath of ink deposited onto print media


484


has been completed, print media


484


is moved an appropriate distance, in preparation for the next swath. This invention is also applicable to fluid dispensing systems employing alternative means of imparting relative motion between the fluid ejection cartridges and the print media, such as those that have fixed fluid ejection cartridges and move the print media in one or more directions, and those that have fixed print media and move the fluid ejection cartridges in one or more directions.




Referring to

FIG. 5



a


an alternate embodiment of the present invention is shown in a simplified cross-sectional view. The fluid has been omitted from

FIG. 5



a


to better provide a clear view of the drawing. In this embodiment, the filter assembly includes filter material


542


formed substantially as a bag acting as compliant portion


540


, and sealed to non-compliant portion


530


inside fluid container


510


. Filter spring


548


acts to return filter material


542


to an expanded form as fluid flow decreases or stops. Non-compliant portion


530


forms fluid outlet


554


that is fluidically coupled to standpipe


578


which provides a fluid path for fluid flowing to fluid ejector


556


. Ejector head


570


is formed by substrate


572


, fluid ejector


556


, nozzle layer


574


, nozzle


558


, and chamber layer


571


, which defines the side walls of an ejector chamber. Fluid inlet


550


includes septum


551


and is fluidically coupled to fluid container


510


. One end of regulator lever


562


forms valve


552


having a valve seat that mates with valve seat


554


. Flexible bag


565


and vent


569


perform similar functions as described above, and as shown in

FIG. 3



a.






When regulator lever


562


rotates causing valve


552


to open fluid will flow through septum


551


into fluid container


510


applying a force (i.e. the back pressure of a fluid delivery system) to compliant portion


540


that includes filter material


542


. This applied force or pressure causes filter material


542


to deflate as shown in

FIG. 3



b


with a corresponding decrease in internal volume


546


of compliant portion


540


. The decrease in internal volume


546


compresses filter spring


548


. In addition, this decrease in internal volume


546


of compliant portion


540


provides a more gradual rise in pressure observed in the vicinity of the one or more fluid ejectors disposed on substrate


572


of fluid ejector head


570


. As fluid ejection cartridge


500


fills with fluid, flexible bag


565


deflates causing valve seat


552


to close decreasing the force or pressure of the fluid delivery system on compliant portion


540


. This decrease in pressure causes filter material


542


to expand, via the force exerted by compressed filter spring


548


, with a corresponding increase in internal volume


546


of compliant portion


540


. The increase in internal volume


546


acts to provide a more gradual decrease in pressure observed in the vicinity of the fluid ejectors on substrate


572


.




Although this embodiment, depicts fluid flowing from the outside of the bag formed by filter material


542


it is also possible to form the filter assembly whereby fluid would flow from the inside of the bag to the outside. In such an assembly the bag expands when fluid flows out of the bag placing filter spring


548


in tension producing an increase in internal volume


546


. Then as the fluid flow decreases the bag deflates relieving the tension on filter spring


548


.




Referring to

FIG. 6



a


an alternate embodiment of the present invention is shown in a simplified cross-sectional view. The fluid has been omitted from

FIG. 6



a


to better provide a clear view of the drawing. In this embodiment, filter assembly


620


includes filter frame


632


that is compliant and forms compliant portion


640


. Filter material


642


and


644


formed in a substantially rigid manner forms non-compliant portion


630


, and is sealed to compliant portion


640


disposed inside of fluid container


610


. Filter frame


632


, preferably, is heat staked to filter material


642


and


644


. However, depending on the particular materials utilized for filter material


642


and


644


and filter frame


632


, adhesives and other mechanical fastening methods may also be utilized to attach filter material


642


and


644


to filter frame


632


.




In this embodiment when fluid flows from the outside of filter assembly


620


through filter material


642


and


644


into internal volume


646


filter frame


632


flexes or deforms providing the change in internal volume


646


that provides a more gradual rise in pressure observed in the vicinity of the one or more fluid ejectors. Whether internal volume increases or decreases depends both on the dimensions of filter frame


632


as well as on the elastic properties of the material used to form filter frame


632


. Filter frame


632


can be formed from any of the metal or polymer well known in the art. The actual frame material utilized depends both, on the particular application in which the fluid ejection cartridge will be utilized, as well as on characteristics of the filter material such as the materials chemical and thermal robustness. Preferably, the frame material is a thermoplastic polymer, and more preferably an injection moldable thermoplastic polymer such as polyethylene, polypropylene or polyester to name a few. Although

FIGS. 6



a


and


6




b


depict a filter assembly utilizing fluid flow from outside the assembly to the internal volume inside the assembly other structures where fluid flows from inside the filter assembly to the outside may also be utilized.




Referring to

FIG. 7



a


an alternate embodiment of the present invention is shown in a simplified cross-sectional view. The fluid has been omitted from

FIG. 5



a


to better provide a clear view of the drawing. In this embodiment, filter assembly


720


includes pleated portion


748


attached between filter frame


732


and filter material


742


and


744


. Pleated portion


748


forms compliant portion


740


and filter frame


732


and filter material


742


and


744


form non-compliant portion


730


. However, filter material


742


and


744


may each be attached to a first and a second filter frame respectively with pleated portion


748


attached to first and second filter frames. In this embodiment, when fluid flows from the outside of filter assembly


720


through filter material


742


and


744


into internal volume


746


pleated portion


748


contracts as shown in

FIG. 7



b


. This contraction provides a decrease in internal volume


746


that results in a more gradual rise in pressure observed in the vicinity of the one or more fluid ejectors. As the fluid ejection cartridge fills with fluid, pleated portion


748


expands with a corresponding increase in internal volume


746


.




Filter frame


732


and pleated portion


748


can be formed from either metal or polymer or some combination thereof. The actual frame material and pleat material utilized depends both, on the particular application in which the fluid ejection cartridge will be utilized, as well as on characteristics such as the materials mechanical properties and chemical robustness. Preferably, the frame and pleat material is a thermoplastic polymer, and more preferably an injection moldable thermoplastic polymer such as polyethylene, polypropylene or polyester to name a few.




While the present invention has been particularly shown and described with reference to the foregoing preferred and alternative embodiments, many variations may be made therein without departing from the spirit and scope of the invention as defined in the following claims. For example,

FIGS. 3



a


-


3




d


depict an embodiment where the filter frame is rigid and the filter material is compliant, whereas the embodiment shown in

FIGS. 6



a


-


6




b


depicts the filter frame as complaint and the filter material as rigid. Embodiments having attributes of both may also be utilized in the present invention where the filter frame and the filter material have some degree of compliance. Thus, the foregoing embodiments are illustrative, and no single feature or element is essential to all possible combinations that may be claimed.



Claims
  • 1. A fluid ejection cartridge comprising:a fluid container having a fluid inlet and a fluid outlet; at least one fluid ejector fluidically coupled to said fluid container outlet; a fluid regulator fluidically coupled to said fluid container inlet; and a filter assembly having a compliant portion with an internal volume fluidically coupled to said fluid container outlet wherein said internal volume changes when fluid flows into said fluid container.
  • 2. The fluid ejection cartridge of claim 1, wherein said fluid regulator further comprises a fluid valve.
  • 3. The fluid ejection cartridge of claim 2, wherein said fluid valve further comprises a septum.
  • 4. The fluid ejection cartridge of claim 1, wherein said fluid regulator is disposed within said fluid container.
  • 5. The fluid ejection cartridge of claim 1 wherein said filter assembly is disposed within said fluid container.
  • 6. The fluid ejection cartridge of claim 1, wherein said fluid regulator further comprises at least one lever.
  • 7. The fluid ejection cartridge of claim 6, wherein said at least one lever further comprises a valve seat.
  • 8. The fluid ejection cartridge of claim 1, wherein said filter assembly further comprises a filter frame.
  • 9. The fluid ejection cartridge of claim 8, wherein said filter frame is compliant.
  • 10. The fluid ejection cartridge of claim 9, further comprises a rigid filter material attached to said compliant frame.
  • 11. The fluid ejection cartridge of claim 8, wherein said filter frame forms a non-compliant portion of said filter assembly.
  • 12. The fluid ejection cartridge of claim 1, wherein said compliant portion further comprises a filter material formed as a bag.
  • 13. The fluid ejection cartridge of claim 1, wherein said filter assembly further comprises a thermoplastic polymer filter frame.
  • 14. The fluid ejection cartridge of claim 1, wherein said filter assembly further comprises a rigid filter media attached to said compliant portion, and said compliant portion is attached to a filter frame.
  • 15. The fluid ejection cartridge of claim 14, wherein said compliant portion further comprises a pleated portion.
  • 16. The fluid ejection cartridge of claim 1, wherein said filter assembly further comprises a rigid filter media attached to a filter frame and said filter frame is attached to said compliant portion.
  • 17. The fluid ejection cartridge of claim 16, wherein said compliant portion further comprises a pleated portion.
  • 18. The fluid ejection cartridge of claim 1, wherein said filter assembly further comprises a filter frame wherein said compliant portion includes an elastic filter material mounted to said filter frame.
  • 19. The fluid ejection cartridge of claim 1, wherein said fluid inlet is fluidically coupled to a secondary fluid reservoir.
  • 20. The fluid ejection cartridge of claim 1, further comprising:a substrate wherein said at least one fluid ejector is disposed on said substrate; a chamber layer disposed on said substrate, wherein said chamber layer defines an ejection chamber; and a nozzle layer containing at least one nozzle fluidically coupled to said at least one fluid ejector.
  • 21. The fluid ejection cartridge of claim 20, wherein said fluid container, said filter assembly, said substrate, and said nozzle layer are formed as an integral replaceable unit.
  • 22. The fluid ejection cartridge of claim 1, wherein said fluid container further comprises an ejectable fluid.
  • 23. The fluid ejection cartridge of claim 1, wherein said filter assembly includes a filter material having a mean pore size range from about one micron to about 50 microns.
  • 24. The fluid ejection cartridge of claim 1, wherein said filter assembly includes a filter material having a mean pore size range from about two microns to about 10 microns.
  • 25. The fluid ejection cartridge of claim 1, wherein said filter assembly further comprises a filter material having a flow rate of between 20 milliliters per minute to about 300 milliliters per minute at a pressure less than about eight inches of water and at a viscosity of less than about 25 centipoise.
  • 26. The fluid ejection cartridge of claim 1, wherein said filter assembly further comprises a filter material having a flow rate of between 40 milliliters per minute to about 100 milliliters per minute at a pressure less than about five inches of water and at a viscosity of less than about 15 centipoise.
  • 27. The fluid ejection cartridge of claim 1, wherein said filter assembly further comprises a filter material having a flow rate of between 45 milliliters per minute to about 55 milliliters per minute at a pressure less than about 2 inches of water and at a viscosity of less than about 5 centipoise.
  • 28. The fluid ejection cartridge of claim 1, wherein said filter assembly further comprises a polymer filter material.
  • 29. The fluid ejection cartridge of claim 28, wherein said polymer filter material includes a polysulfone porous membrane.
  • 30. The fluid ejection cartridge of claim 28, wherein said polymer filter material includes a polytetrafluoroethylene porous membrane.
  • 31. A fluid ejection cartridge comprising:a fluid container having a fluid inlet and a fluid outlet; at least one fluid ejector fluidically coupled to said fluid container outlet; a fluid regulator fluidically coupled to said fluid container inlet; and a filter assembly disposed within said fluid container, comprising: a thermoplastic polymer filter frame; and a compliant polymer filter material attached to said thermoplastic polymer filter frame, forming a compliant portion, having an internal volume fluidically coupled to said fluid container outlet wherein said internal volume changes when fluid flows into said fluid container.
  • 32. A fluid dispensing system comprising:at least one fluid ejection cartridge of claim 1; at least one secondary fluid reservoir; at least one flexible fluid conduit fluidically coupling said at least one secondary fluid reservoir to said at least one fluid ejection cartridge; and a sheet advancer for advancing a print media, wherein said sheet advancer and said at least one fluid ejection cartridge are capable of dispensing fluid on a first portion of said print media.
  • 33. The fluid dispensing system of claim 32, wherein said sheet advancer and said drop-firing controller are capable of dispensing said fluid in a two dimensional array on said first portion and on a second portion of said sheet.
  • 34. A method of manufacturing a fluid ejection cartridge comprising the steps of:forming a fluid container having a fluid inlet and a fluid outlet; creating at least one fluid ejector fluidically coupled to said fluid container outlet; and mounting a filter assembly to said fluid outlet, wherein said filter assembly includes a compliant portion with an internal volume fluidically coupled to said fluid container outlet wherein said internal volume changes when fluid flows into said fluid container.
  • 35. The method of claim 34, further comprising the step of forming a fluid regulator fluidically coupled to said fluid container inlet.
  • 36. The method of claim 35, wherein said step of forming a fluid regulator further comprises the step of forming a helical labyrinth path to atmospheric air.
  • 37. The method of claim 35, wherein said step of forming a fluid regulator further comprises the step of forming a fluid valve.
  • 38. The method of claim 34, wherein said step of mounting a filter assembly further comprises the step of forming a filter material as a bag.
  • 39. The method of claim 34, wherein said step of mounting a filter assembly further comprises the step of forming a filter frame.
  • 40. The method of claim 39, wherein said step of forming a filter frame further comprises the step of forming a compliant filter frame.
  • 41. The method of claim 40, wherein said step of forming a compliant filter frame further comprises the step of attaching a rigid filter material to said complaint filter frame.
  • 42. The method of claim 39, wherein said step of forming a filter frame further comprises the step of forming a rigid filter frame.
  • 43. The method of claim 42, wherein said step of forming a rigid filter frame further comprises the step of attaching a compliant filter material to said rigid filter frame.
  • 44. The method of claim 34, wherein said step of mounting a filter assembly further comprises the step of attaching a rigid filter material to said compliant portion, and said compliant portion is attached to a filter frame.
  • 45. The method of claim 44, wherein said attaching step further comprises the step of attaching said rigid filter material to a pleated portion, and said pleated portion is attached to a filter frame.
  • 46. The method of claim 34, wherein said step of mounting a filter assembly further comprises the step of attaching a rigid filter material to a filter frame and said filter frame is attached to said compliant portion.
  • 47. The method of claim 46, wherein said attaching step further comprises the step of attaching said rigid filter material to a filter frame and said filter frame is attached to a pleated portion.
  • 48. The method of claim 34, wherein said step of mounting a filter assembly further comprises the step of mounting an elastic filter media to a rigid frame.
  • 49. The method of claim 34, further comprises the step of fluidically coupling said fluid inlet to a secondary fluid reservoir.
  • 50. The method of claim 34, further comprises the steps of:forming a substrate wherein said at least one fluid ejector is disposed on said substrate; creating an ejection chamber disposed on said substrate; and creating a nozzle layer having at least one nozzle fluidically coupled to said at least one fluid ejector.
  • 51. The method of claim 34, further comprises the step of creating said fluid container, said filter assembly, said substrate, and said nozzle layer as an integral replaceable unit.
  • 52. The method of claim 34, further comprises the step filling said fluid container with an ejectable fluid.
  • 53. The fluid ejection cartridge made by method 34.
  • 54. A method of using a fluid ejection cartridge comprising the steps of:containing a fluid within a fluid container having a fluid inlet and a fluid outlet; coupling at least one fluid ejector to said fluid container outlet; regulating said fluid in said fluid container at a predetermined level; filtering said fluid through a fluid assembly having a compliant portion with an internal volume fluidically coupled to said fluid container outlet; and changing said internal volume when fluid flows into said fluid container.
  • 55. The method of claim 54, further comprising the step of ejecting fluid from said at least one fluid ejector.
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5880748 Childers et al. Mar 1999 A
6084617 Balazer Jul 2000 A
6084618 Baker Jul 2000 A
6152560 Hollands Nov 2000 A
6250747 Hauck Jun 2001 B1
6260957 Corley, Jr. et al. Jul 2001 B1
6270205 Takata Aug 2001 B1
20030150821 Bates et al. Aug 2003 A1