1. 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 air or gas bubbles forming in various portions of the system including the fluid supply may increase. Fluid ejection cartridges and fluid supplies provide good examples of the problems facing the practitioner in preventing the formation of gas bubbles in the supply container, microfluidic channels, and chambers of the fluid ejection cartridge. The fluid supply in inkjet printing systems is just one common example.
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, image quality and lower cost. 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 semi-permanent printheads with replaceable ink reservoirs mounted on the printheads. In a typical ink jet printing system with semi-permanent pens and replaceable ink supplies, the replacement ink supplies are generally provided with seals over the fluid interconnects to prevent ink leakage and evaporation, and contamination of the interconnects during distribution and storage. Generally a pressure regulator is added to the reservoir to deliver the ink to the printhead at the optimum backpressure. Such printing systems strive to maintain the backpressure of the ink within the printhead to within as small a range as possible. Typically changes in back pressure, of which air bubbles are only one variable, may greatly effect print density as well as print and image quality. In addition, even when not in use the volume of air entrapped in a fluid supply may increase when subjected to stress such as dropping. Subsequent altitude excursions typically cause this air to expand and displace ink ultimately leading to the displaced ink being expelled from the supply container. The expelled ink will cause damage to the product package or other container in which it is located.
In addition, improvements in image quality have led to an increase in the complexity of ink formulations that increases the sensitivity of the ink to the ink supply and print cartridge materials that come in contact with the ink. Typically, these improvements in image quality have led to an increase in the organic content of inkjet inks that results in a more corrosive environment experienced by the materials utilized, thus, raising material compatibility issues.
In order to reduce both weight and cost many of the materials currently utilized are made from polymers such as plastics and elastomers. Many of these plastic materials, typically, utilize various additives, such as stabilizers, plasticizers, tackifiers, polymerization catalysts, and curing agents. These low molecular weight additives are generally added to improve various processes involved in the manufacture of the polymer, and to reduce cost without severely impacting the material properties. Since these additives, typically, are low in molecular weight compared to the molecular weight of the polymer, they can be leached out of the polymer by the ink, react with ink components, or both, more easily than the polymer itself. In either case, the reaction between these low molecular weight additives and ink components can also lead to the formation of precipitates or gelatinous materials, which can further result in degraded print or image quality.
If these problems persist, the continued growth and advancements in inkjet printing and other micro-fluidic devices, seen over the past decade, will be reduced. Current ink supply technology continually struggles with maximizing the amount of ink delivered while continuing to meet shipping stress and altitude specifications. Consumer demand for cheaper, smaller, more reliable, higher performance devices constantly puts pressure on improving and developing cheaper, and more reliable manufacturing materials and processes. The ability to optimize fluid ejection systems, will open up a wide variety of applications that are currently either impractical or are not cost effective.
a is a perspective view of a reversibly fluid absorbing material according to an embodiment of the present invention.
b is a cross-sectional view along 2b-2b showing the fluid absorbing material shown in
c is a cross-sectional view along 2c-2c showing the fluid absorbing material shown in
a is a perspective view of a fluid absorbing material according to an alternate embodiment of the present invention.
b is a perspective view of a fluid absorbing material according to an alternate embodiment of the present invention.
c is a schematic elevational view of a fluid absorbing material according to an alternate embodiment of the present invention.
a is a cross-sectional view of a portion of a fluid absorbing material according to an alternate embodiment of the present invention.
b is an expanded view of the fluid absorbing material shown in
a is an exploded perspective view of an ink jet cartridge according to an alternate embodiment of the present invention.
b is an expanded cross-sectional view of the fluid ejector head shown in
A cross-sectional view of an embodiment of fluid supply 100 employing the present invention is illustrated in
Capillary material 130 is contained within body 120 and is configured to facilitate reliable flow of fluid from fluid supply 100 through an opening (not shown) in body 120 to a fluid ejection system (not shown). In addition, capillary material 130 creates capillary forces that regulate the backpressure of fluid supply 100. In this embodiment, the fibers are oriented lengthwise in body 120, as represented by the horizontal lines in
It should be noted that the drawings are not true to scale. Further, various elements have not been drawn to scale. Certain dimensions have been exaggerated in relation to other dimensions in order to provide a clearer illustration and understanding of the present invention.
In addition, although some of the embodiments illustrated herein are shown in two dimensional views, with various regions having depth and width, it should be clearly understood that these regions are illustrations of only a portion of a device that is actually a three dimensional structure. Accordingly, these regions will have three dimensions, including length, width, and depth, when fabricated on an actual device. Moreover, while the present invention is illustrated by various embodiments, it is not intended that these illustrations be a limitation on the scope or applicability of the present invention. Further, it is not intended that the embodiments of the present invention be limited to the physical structures illustrated. These structures are included to demonstrate the utility and application of the present invention in presently preferred embodiments.
a is a perspective view illustrating an embodiment of a reversibly fluid absorbing material employing the present invention. In this embodiment capillary material 230 includes thread fibers 240 and 240′ sewn or woven within the body of capillary material 230. Thread fibers 240 and 240′ each have a surface energy less than the surface energy of capillary material 230. Capillary material 230, in this embodiment, is a BPF material formed from individual fibers with an essentially uniform diameter of about 14 micrometers providing a mass for capillary material 230 with an overall density of about 0.13 grams per cubic centimeter. However, in alternate embodiments, a fiber diameter in the range from about 5 micrometers to about 50 micrometers also may be utilized to form capillary material 230. In one particular embodiment, the BPF material includes fibers each having an individual diameter of about 20 micrometers plus or minus 2 micrometers with an overall density of about 0.15 grams per cubic centimeter. In still other embodiments, a mixture of fibers having a range of diameters from about 5 micrometers to about 50 micrometers may be utilized to form capillary material 230. However, in alternate embodiments, capillary material may be formed utilizing other materials as described above and may have larger or smaller diameters as well as a higher or lower density. The particular material, diameter, and density utilized will depend on various factors such as the particular fluid being stored, the amount of the fluid contained in the supply, the particular environmental conditions the supply will be stored and used in, and the expected lifetime of the supply.
As illustrated in
In this embodiment, thread fiber 240 forms a single row formed in a serpentine or folded pattern with eight straight portions 241 of fiber 240 equally spaced and extending from top face 233 to bottom face 234 of capillary material 230. In addition, thread fiber 240′ forms two rows one row on each side of the serpentine structure formed by thread fiber 240. Further, each row of thread fiber 240′ also forms a serpentine pattern with three straight portions 241′ extending from one end surface 232 to the other end surface 232′ as illustrated in
It is believed that the lower surface energy fiber or thread compared to the surface energy of the capillary material provides a path for entrapped air or gas to travel more easily in the case of thread fiber 240 from bottom face 234 to top face 233 and in the case of thread fiber 240′ air or gas may travel more easily to either end surface 232 or 232′. It has been empirically determined that by utilizing a lower surface energy thread sewn into the capillary material a 40 to 50 percent increase in the altitude survival rate after stress is achievable. This provides for an increase in the amount of fluid that may be contained within the fluid supply while keeping the volume of the supply constant.
a and 3b are perspective views showing alternate embodiments of a capillary material employing the present invention. In the embodiment shown in
An alternate embodiment of a capillary material that may be utilized in the present invention is shown in
An alternate embodiment of the present invention where the capillary material includes short lengths of lower surface energy fibers randomly dispersed within the fibers forming the capillary material is shown in simplified schematic diagrams in
Scanning carriage 527 is moved through the print zone on a scanning mechanism which includes slide rod 526 on which scanning carriage 527 slides as scanning carriage 527 moves through a scan axis. A positioning means (not shown) is used for precisely positioning scanning carriage 527. In addition, a paper advance mechanism (not shown) is used to step print medium 504 through the print zone as scanning carriage 527 is moved along the scan axis. Electrical signals are provided to the scanning carriage for selectively activating the printheads by means of an electrical link such as ribbon cable 528.
The specific configuration of ink reservoirs and printheads illustrated in
a illustrates, in an exploded perspective view, an alternate embodiment of the present invention where ink jet print cartridge 716 includes capillary material 730 disposed within fluid reservoir 724. Print cartridge 716 is configured to be used by a fluid deposition system such as ink jet printing system 502 shown in
Cartridge crown 774 includes a cover or cap configured to cooperate with cartridge body 720 to enclose interior volume 776 and fluid absorbing material 730 disposed within interior volume 776. In this embodiment, crown 774 is configured to form a fluidic seal with cartridge body 720; however, in alternate embodiments, other capping and sealing arrangements also may be utilized. Crown 774 also includes fill port 750. Fill port 750 generally comprises an inlet through crown 774, enabling print cartridge 716 to be filled or refilled with fluid. In the particular embodiment illustrated, fill port 750 includes a mechanism configured to seal the opening provided by fill port 750 once filling of the print cartridge is completed. In an alternate embodiment, the sealing mechanism may automatically seal any opening formed during the filling process, such as a valving mechanism or a septum. In still another embodiment, fill port 750 may be configured to be manually closed when not in use. Although in the embodiment illustrated in the exploded view shown in
A cross-sectional view of fluid ejector head 706 of fluid ejection cartridge 716 is shown in
A fluid dispensing system employing the present invention is schematically illustrate in
Fluid ejection system 808 generally comprises a mechanism configured to eject fluid onto fluid receiving structure 804. In one embodiment, fluid ejection system 808 includes one or more fluid ejection cartridges wherein each cartridge has a plurality of fluid ejector actuators and nozzles configured to dispense fluid in the form of drops in a plurality of locations onto fluid receiving structure 804. In alternate embodiments, fluid ejection system 808 may include other devices configured to selectively eject fluid onto fluid receiving structure 804. For example, fluid receiving structure 804 may include a tray having multiple vials or containers disposed thereon. In such an embodiment, fluid ejection system 808 may include a single fluid ejector or tightly grouped set of fluid ejectors so that each fluid ejector or grouped set of ejectors dispenses a fluid into an opening in a desired container. Fluid ejection system 808 may utilize any of the embodiments described above of reversibly fluid absorbing material.
Fluid supply 800 supplies the fluid to fluid ejection system 808 via fluid distribution device 810. In one particular embodiment, fluid distribution device 810 comprises a manifold having internal channels to route the fluid from fluid supply 800 to the appropriate fluid ejectors disposed within fluid ejection system 808. In still other embodiments, fluid distribution device 810 may include one or more conduits such as tubes to route the fluid to the fluid ejection system. Fluid supply 800 includes a reversibly fluid absorbing material similar to any of the embodiments described above. Fluid ejection system 808 also may include a reversibly fluid absorbing material similar to any of the embodiments described above.
Transport mechanism 868 comprises a device configured to move fluid receiving structure 804 relative to fluid ejection system 808. Transport mechanism 868 includes one or more structures configured to support and position either fluid receiving structure 804 or to support and position fluid ejection system 808 or both. In one embodiment, a support (not shown) is configured to stationarilly support fluid ejection system 808 as transport mechanism 868 moves fluid receiving structure 804. In printing applications, such a configuration is commonly referred to as a page-wide-array printer where fluid ejection system 808 may substantially span a dimension of fluid receiving structure 804. In an alternate embodiment, a support is configured to reciprocally move fluid ejection system 808 back and forth across a dimension of fluid receiving structure 804 while another support is configured to move fluid receiving structure 804 in a different direction. In still other embodiments, transport mechanism 868 may be omitted wherein fluid ejection system 808 and fluid receiving structure 804 are configured to dispense fluid in desired locations onto or into fluid,receiving structure 804 without lateral movement during the dispensing operation.
Ejection controller 872 generally comprises a processor configured generate control signals which direct the operation of fluid ejection system 808 and sends signals to fluid receiving structure controller 870. The term processor, in this embodiment, may include any conventionally known or future developed processor that executes sequences of instructions contained in memory. Execution of the sequences of instructions causes the processing unit to perform steps such as generating control signals. The instructions may be loaded in a random access memory (RAM) for execution by the processing unit from a read only memory (ROM), a mass storage device, or some other persistent storage device. In other embodiments, hard wired circuitry may be used in place of or in combination with software instructions to implement the functions described. Ejection controller 872 is not limited to any specific combination of hardware circuitry and software, nor to any particular source for the instructions executed by the processing unit.
Ejection controller 872 receives data signals from one or more sources (as illustrated by data from host 871) representing the manner in which fluid is to be dispensed. Ejection controller 872 generates the control signals that direct the timing at which drops are ejected from fluid ejection system 872 as well as movement of the fluid ejection system in those embodiments in which the fluid ejection system moves relative to fluid receiving structure 804. The source of such data may comprise a host system such as a computer or a portable memory reading device associated with fluid dispensing system 802. Such data signals may be transmitted to ejection controller 872 along infrared, optical, electric or by other communication modes. In addition, in this embodiment, based upon such data signals, ejection controller 872 also sends signals to fluid receiving structure controller that direct the movement of transport mechanism 868. However, in alternate embodiments, data signals may be sent directly to fluid receiving structure controller to direct movement of transport mechanism 868.
The present application is related to co-pending patent application Ser. No. ______ filed on the same day herewith by Joseph W. Stellbrink and Eric A. Ahlvin and entitled “Fluid Supply Media.”