Patent Grant
7399074
The present invention generally relates to printing systems. More particularly, the present invention relates to a ink tank for printheads such as an inkjet wide-feature printhead.
Conventional printing devices generally include one or more ink tanks that store ink and supply it to a printhead such as a thermal inkjet printhead. By way of example, inkjet printing is a conventional technique by which printing is normally accomplished without contact between the printing apparatus and the substrate, or medium, on which the desired print characters are deposited. Conventional inkjet printing devices such as a fax, printer, photo printer, all-in-one device, plotter, or any other device incorporating inkjet printing technology typically include one or more ink tanks in which ink is stored and supplies ink from the tank to one or more inkjet printheads, which dispense the ink for printing. In one embodiment of the inkjet printing device, the ink tank and printhead are generally placed within a movable print carriage of the inkjet device. In another embodiment, the ink tank is fixedly connected to the inkjet device while the printhead is connected to the movable print carriage. In still another embodiment of the inkjet printing device, both the printhead and ink tank are combined into single unit print cartridge connected to a movable carriage.
Due to conventional ink tank designs, such tanks can provide very inconsistent ink pressure to the inkjet printhead, which can cause high variability in the ink jetting operation. This high variability in the ink jetting operation can create high variability in the print quality of the final product, which is very undesirable. Another opportunity for improvement with conventional ink tanks is the depriming of the printhead, which can cause the printhead to fail. This can occur if printing continues after the ink tank has been emptied of all its ink.
Accordingly, there is a need for an improved ink tank.
Accordingly, the present invention is intended to address and obviate problems and shortcomings and otherwise improve previous ink tanks for inkjet printing devices.
One exemplary embodiment of the present invention is an ink tank for an inkjet printing device. The ink tank includes a housing for containing ink, first and second chambers within the housing, and a partition separating the first and second chambers. The ink tank also includes a communication port connecting the first chamber in fluid communication with the second chamber, a tank outlet disposed within a wall of the housing, and a high capillary pressure producing member in direct communication with the outlet. Capillary pressure, as used herein, denotes the magnitude of vacuum (with respect to the ambient atmosphere), that characterizes the physical state of the ink mass under consideration.
Another exemplary embodiment of the present invention is an ink tank for an inkjet printing device. The ink tank includes a housing, first and second chambers for containing ink disposed within the housing, and a partition separating the first and second chambers. The ink tank also includes a communication port connecting the first chamber in fluid communication with the second chamber, a capillary pressure producing member disposed within the second chamber, a tank outlet disposed within a wall of the second chamber, and a first space for containing free ink disposed within the second chamber such that ink may flow from the first space through the capillary pressure producing member and exit the outlet without having to travel through the communication port.
Still another exemplary embodiment of the present invention is an ink tank for an inkjet printing device. The ink tanks include a housing, first and second chambers for containing ink disposed within the housing, a communication port connecting the first chamber in fluid communication with the second chamber, a tank outlet disposed within a wall of the housing, a capillary pressure producing member disposed above the outlet, and a first space for containing free ink disposed above the capillary pressure producing member within the housing such that free ink may flow substantially downward from the first space through the capillary pressure producing member and exit the outlet.
While the specification concludes with claims particularly pointing out and distinctly claiming the invention, it is believed the same will be better understood from the following description taken in conjunction with the accompanying drawings in which:
The embodiments set forth in the drawings are illustrative in nature and not intended to be limiting of the invention defined by the claims. Moreover, individual features of the drawings and the invention will be more fully apparent and understood in view of the detailed description.
Reference will now be made in detail to various embodiments of the invention, examples of which are illustrated in the accompanying drawings, wherein like numerals indicate similar elements throughout the views.
The present invention provides an ink tank configured to supply ink to an inkjet printhead for a printing device at backpressures that vary less than conventional ink tanks. While the exemplary embodiments illustrated herein describe ink tanks for inkjet printer technology, as will be apparent to those of ordinary skill in the art the present invention may be employed in other ink tanks for print technologies such as printheads for print cartridges for inkjet printers, toner cartridges for laser printers, ink tanks for fax, photo printers, all-in-one devices, or plotters, or any other device incorporating printing technology.
Referring to
Ink tank may also include a reservoir 11 and a partition wall 18 that separates reservoir 11 into a first chamber 14 and a second chamber 16. Partition 18 (e.g., a wall) extends downwardly from top wall 12a toward bottom wall 12b. A communication port 26 positioned between partition wall 18 and bottom wall 12b connects first chamber 14 in fluid communication with second chamber 16.
A tank outlet 28 for supplying ink from the reservoir 11 to a print head (not shown) is disposed within a wall (e.g., bottom wall 12b) of housing 12. Ink tank 10 also may include one or more capillary pressure producing members disposed within first and/or second chambers 14 and 16, respectively. In the exemplary embodiment shown in
It is understood that second chamber 16 may include additional capillary pressure producing members in addition to high capillary pressure producing member 20. It is also understood that a capillary pressure producing member rated at a operating capillary pressure different than high capillary pressure member 20 (e.g., less than 8 cmH2O) may be used in place of high capillary pressure producing member 20. Exemplary capillary pressure producing members that may be used with the present invention include, but are not limited to, conventional hydrophobic foam material such as unfelted polyurethane open cell foam, fiber materials such as polyethylene, polypropylene, polyester or any blend thereof, felted foams, and other capillary pressure producing members as known to one of ordinary skill in the art.
As used herein, “direct communication” is defined as fluid communication between two components or elements (e.g., high capillary pressure producing member 20 and first space 30) such that a fluid (e.g., ink) may flow from the first component (e.g., first space 30) to the second component (e.g., high capillary pressure producing member 20) without requiring the fluid to flow through any other component or element. For example, as shown in
First chamber 14 may, in the exemplary embodiment shown, include any conventional capillary pressure producing members at a variety of operating capillary pressures. In the exemplary embodiment, first chamber 14 includes a low capillary pressure producing member 22 and a medium capillary pressure producing member 24.
Low capillary pressure producing member 22 may be positioned in the upper portion of first chamber 14 such that it is adjacent top wall 12a. Medium capillary pressure producing member 24 may be positioned in the lower portion of first chamber 14 below low capillary pressure producing member 22 such that the low capillary pressure producing member is adjacent to bottom wall 12b and in direct communication with communication port 26. Low capillary pressure producing member 22 may comprise an operating capillary pressure from about 3 cmH2O to about 6 cmH2O. Medium capillary producing member 24 may comprise an operating capillary pressure from about 5 cmH2O to about 10 cmH2O. Exemplary low and medium capillary pressure producing members that may be used with the present invention are random orientation felts with densities of 0.10 g/cc to 0.15 g/cc of 20 micrometer to 40 micrometer diameter fibers and 0.10 g/cc to 0.20 g/cc of 15 micrometer to 35 micrometer diameter fibers, respectively.
Ink tank 10 may also include an ambient air vent 32 disposed within housing 12, providing an opening for ambient air to enter into the reservoir. As shown in
Ink tank 10 may also include a sensor operable to detect the ink and/or the level of ink within the tank. The sensor can be included within the reservoir to detect the presence of ink so that printing may be stopped before the reservoir empties completely. If printing continues after the reservoir has emptied, the printhead may deprime and fail. In the exemplary embodiment, ink sensor 13 is placed substantially along the bottom of and within first space 30 (just above high capillary pressure producing member 20). Ink sensor 13 is configured to detect the presence of ink and/or the lack thereof contained within first space 30 and stop the printing process if no ink is detected. Since sensor 13 is positioned within first space 30 (and the free ink), sensor 13 may comprise an optical sensor to gauge the volume of ink remaining in the tank in order to stop the printing before the printhead deprimes. It is understood that sensor 13 may be positioned in other places within ink tank 10 and that other conventional ink sensors may be used with the present invention as known to one of ordinary skill in the art, including but not limited to infrared and Hall effect sensors.
Still referring to
As the ink is consumed from ink tank 10, a boundary 15 between the ink and ambient air will move down first chamber 14 (e.g., through low capillary pressure producing member 22 and then medium capillary pressure producing member 24) until boundary reaches communication port 26. At which point, air begins to flow through communication port 26 and air path 34 into first space 30, which rises to the top of second chamber 16 (e.g., first space 30) to form a second boundary (not shown) at the top of first space 30 between ambient air and first ink in first space 30. As the ink is continued to be consumed, the second boundary moves down first space 30 until it reaches a level adjacent sensor 13. At which point, sensor 13 signals the printing device to stop the printing operation to protect the printhead from depriming.
Referring to
A tank outlet 68 for supplying ink from the reservoir 51 to a print head (not shown) is disposed within a wall (e.g., bottom wall 52b) of housing 52. Ink tank 50 also may include one or more capillary pressure producing members disposed within first and/or second chambers 54 and 56, respectively. In the exemplary embodiment shown in
It is understood that second chamber 56 may include additional capillary pressure producing members in addition to high capillary pressure producing member 60. It is also understood that a capillary pressure producing member rated at a operating capillary pressure different than the high capillary pressure (e.g., less than 10 cm cmH2O) may be used in place of high capillary pressure producing member 60. Exemplary capillary pressure producing members that may be used with the present invention include, but are not limited to, conventional hydrophobic foam material such as unfelted polyurethane open cell foam, fiber materials such as polyethylene, polypropylene, polyester or any blend thereof, felted foams, and other capillary pressure producing members as are known to one of ordinary skill in the art.
First chamber 54 may comprise any type of conventional capillary pressure producing member at a variety of operating capillary pressures. In the exemplary embodiment, first chamber 54 includes a low capillary pressure producing member 62 positioned in the upper portion of first chamber 54 such that it is adjacent top wall 52a. In the lower portion of first chamber 54 (adjacent bottom wall 52b), a second free space 64 for containing free ink is provided within the reservoir 51. Second free space 64 is adjacent to and in direct communication with communication port 66. In this exemplary embodiment, low capillary pressure member 62 controls the bubbling pressure. Low capillary pressure producing member 62 may comprise an operating capillary pressure from about 3 cmH2O to about 6 cmH2O. Exemplary low capillary pressure producing members that may be used with the present invention are random orientation felts with densities of 0.10 g/cc to 0.15 g/cc of 20 micrometer to 40 micrometer diameter fibers.
Ink tank 50 may also include an ambient air vent 72 disposed within housing 52, providing an opening for ambient air to enter into the reservoir. As shown in
Ink tank 50 may also include a sensor operable to detect the ink and/or the level of ink within the tank. The sensor is included within the reservoir to detect the presence of ink so that printing may be stopped before the reservoir empties completely. In the exemplary embodiment, ink sensor 53 is placed substantially along the bottom of and within first space 70 (just above high capillary pressure producing member 60). As set forth above in ink tank 50, ink sensor 53 is configured to detect the presence of ink and/or the lack thereof contained within reservoir 51 (e.g., first space 70) and stop the printing process if no ink is detected. Sensor 53 may be any conventional sensor (e.g., optical sensor to gauge the volume of ink) as known to one of ordinary skill in the art. It is understood that sensor 53 may be positioned in other places within ink tank 50 (e.g., second space 64) and that more than one sensor may be used with ink tank 50. Other conventional ink sensors may be used with the present invention as known to one of ordinary skill in the art, including but not limited to infrared and Hall effect sensors.
As ink is supplied to printhead during printing operations via outlet 68, the ink will drain from second chamber 56 only after the free ink (e.g., ink in second space 64) and bound ink (e.g., ink in low capillary pressure member 62) in first chamber 54 has drained. As the ink is consumed from ink tank 50, a boundary 55 between the ink and ambient air will move down first chamber 54 (e.g., through low capillary pressure producing member 62 and then second free ink space 64) until boundary reaches communication port 66. At which point, air begins to flow through communication port 66 and air path 74 into first space 70, which rises to the top of second chamber 56 (e.g., first space 70) to form a second boundary (not shown) at the top of first space 70 between ambient air and free ink in first space 30. As the ink is continued to be consumed, the second boundary moves down first space 70 until it reaches a level adjacent sensor 53. At which point, sensor 53 signals the printing device to stop the printing operation to protect the printhead from depriming.
The exemplary embodiment shown in
Referring to
Ink tank 100 may also include an air path 134 that provides a path from communication port 126 to first chamber 114 and ultimately to an ambient air vent 132. First chamber 114 comprises a capillary pressure producing member 119 (e.g., random orientation felt). Second chamber 116 comprises a first free space 130 for containing free ink. Second chamber 116 (first space 130) is positioned above first chamber 114.
In the exemplary embodiment shown in
In this exemplary embodiment, outlet 128 is disposed within bottom wall 112b and thus in fluid communication with first chamber 114. As set forth above, ink tank 100 also includes vent 132, which is disposed within right side wall 112d, placing ambient air in fluid communication with first chamber 114. In addition, when the ink drains from first chamber 114 such that a boundary 113 between the ink and ambient air passes air path 134, vent 132 is placed in fluid communication with first space 130.
When printing begins and inks begins to be supplied from ink tank 100 from outlet 128, low capillary pressure producing member 122 (portion closest to vent 132 begins to drain or empty of ink first. The liquid level (e.g., boundary 115) lowers until an air path is established from air vent 132 to first free ink space 130. The air path 134 is configured to control the pressure at which the free ink drains into the first chamber 114. The flow of free ink from free space 130 into high capillary pressure producing member 120 keeps it saturated until the free ink volume has been exhausted. A sensor 113 may be positioned in first space 130 such that it may detect the presence of ink in free space 130 or lack thereof, in order to signal the printing device to stop printing.
Accordingly, while some of the alternative embodiments of the present invention have been discussed specifically; other embodiments will be apparent or relatively easily developed by those of ordinary skill in the art. Accordingly, this invention is intended to embrace all alternatives, modifications and variations that have been discussed herein, and others that fall within the spirit and broad scope of the claims.
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| Number | Date | Country | |
|---|---|---|---|
| 20070076066 A1 | Apr 2007 | US |
