Patent Application
20110164080
Thermal ink jet printing technology is widely used in many commercial products such as printers and facsimile machines. Typical ink jet printers include a print head that receives ink from an ink reservoir. An ink channel supplies ink from the ink reservoir to the print head. The print head includes ejection chambers with corresponding nozzles. An ejection chamber creates pressure on the ink within the ejection chamber to eject an ink bubble through a corresponding nozzle. After ejecting ink from the ejection chamber, new ink is drawn into the chamber from the ink channel. However, ink that remains within the chamber and is within the nozzles will be exposed to air. Between printing jobs when the ink does not move from the nozzles, the exposed ink at the nozzles can dry and/or clog the nozzles.
To prevent the print head nozzles from becoming clogged or having a reduced performance because of dried ink, several remedies have been used. One remedy is to cover the area of the print head containing the nozzles with a cap in between print operations. However, the cap is not completely air tight and drying of the ink may still occur over time. Another approach is to periodically eject ink through the nozzles even when not printing, to keep the nozzles clear. However, this approach requires a spittoon to catch the ejected ink and wastes ink that is not used for printing. Other techniques include manually applying a moisturizing solution to the print head or wiping the crusted or dried material off the print head to extend the life of the print head.
One embodiment includes a method for controlling a fluid-jet dispenser that includes a plurality of nozzles for precisely ejecting fluid and a plurality of ejection chambers. The fluid-jet dispenser includes one or more fluid channels for supplying fluid from a fluid reservoir to the plurality of ejection chambers and corresponding nozzles. The method includes detecting that the fluid-jet dispenser has not ejected fluid for a predetermined time. The method includes applying a de-prime pressure that is a negative pressure to withdraw fluid from the nozzles and the ejection chambers to a high capillary force area within each of the one or more fluid channels to remove fluid from the plurality of nozzles.
The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate various example systems, methods, and other example embodiments of various aspects of the invention. It will be appreciated that the illustrated element boundaries (e.g., boxes, groups of boxes, or other shapes) in the figures represent one example of the boundaries. One of ordinary skill in the art will appreciate that in some examples one element may be designed as multiple elements or that multiple elements may be designed as one element. In some examples, an element shown as an internal component of another element may be implemented as an external component and vice versa. Furthermore, elements may not be drawn to scale.
Described herein are example systems, methods and other embodiments associated with de-priming a fluid jet dispensing device (e.g a print head). In one example when a print head is idle, the fluid (e.g. ink) at the nozzles can form a meniscus and be in contact with ambient air for an extended period of time. Ink in contact with air tends to become crusty or harden over time. A nozzle may become completely clogged if the ink on the nozzle is exposed to air too long without any ink being ejected.
In one example system for extending the life of a print head of an ink jet printer, the ink in the print head is at least partially de-primed when the print head has not printed for a predetermined time. De-priming a print head involves pulling ink back from the nozzle and the ejection chamber toward the ink channel. In one embodiment, the ink is removed from the nozzle and/or the ejection chamber so that air remains. The removed ink is drawn back into a narrow ink channel and towards the ink reservoir where the ink is not exposed to air. This prevents the ink from crusting or hardening within the nozzles and/or ejection chambers. De-priming the print head may be used in combination with other techniques used to extend the life of a print head.
The following includes definitions of selected terms employed herein. The definitions include various examples and/or forms of components that fall within the scope of a term and that may be used for implementation. The examples are not intended to be limiting. Both singular and plural forms of terms may be within the definitions.
References to “one embodiment”, “an embodiment”, “one example”, “an example”, and so on, indicate that the embodiment(s) or example(s) so described may include a particular feature, structure, characteristic, property, element, or limitation, but that not every embodiment or example necessarily includes that particular feature, structure, characteristic, property, element or limitation. Furthermore, repeated use of the phrase “in one embodiment” does not necessarily refer to the same embodiment, though it may.
ASIC: application specific integrated circuit.
CD: compact disk.
CD-R: CD recordable.
CD-RW: CD rewriteable.
DVD: digital versatile disk and/or digital video disk.
HTTP: hypertext transfer protocol.
LAN: local area network.
PCI: peripheral component interconnect.
PCIE: PCI express.
RAM: random access memory.
DRAM: dynamic RAM.
SRAM: static RAM.
ROM: read only memory.
PROM: programmable ROM.
EPROM: erasable PROM.
EEPROM: electrically erasable PROM.
WAN: wide area network.
“Computer-readable medium”, as used herein, refers to a medium that stores signals, instructions and/or data. A computer-readable medium may take forms, including, but not limited to, non-volatile media, and volatile media. Non-volatile media may include, for example, optical disks, magnetic disks, and so on. Volatile media may include, for example, semiconductor memories, dynamic memory, and so on. Common forms of a computer-readable medium may include, but are not limited to, a floppy disk, a flexible disk, a hard disk, a magnetic tape, other magnetic medium, an ASIC, a CD, other optical medium, a RAM, a ROM, a memory chip or card, a programmable logic device, a memory stick, and other media from which a computer, a processor or other electronic device can read.
“Logic”, as used herein, includes but is not limited to hardware, firmware, software instructions stored in a computer-readable medium, software in execution on a machine, and/or combinations of each to perform a function(s) or an action(s), and/or to cause a function or action from another logic, method, and/or system. Logic may include a software controlled microprocessor, a discrete logic (e.g., ASIC), an analog circuit, a digital circuit, a programmed logic device, a memory device containing instructions, and so on. Logic may include one or more gates, combinations of gates, or other circuit components. Where multiple logical logics are described, it may be possible to incorporate the multiple logical logics into one physical logic. Similarly, where a single logical logic is described, it may be possible to distribute that single logical logic between multiple physical logics.
An “operable connection”, or a connection by which entities are “operably connected”, is one in which signals, physical communications, and/or logical communications may be sent and/or received. An operable connection may include a physical interface, an electrical interface, and/or a data interface. An operable connection may include differing combinations of interfaces and/or connections sufficient to allow operable control. For example, two entities can be operably connected to communicate signals to each other directly or through one or more intermediate entities (e.g., processor, operating system, logic, software). Logical and/or physical communication channels can be used to create an operable connection.
“Signal”, as used herein, includes but is not limited to, electrical signals, optical signals, analog signals, digital signals, data, computer instructions, processor instructions, messages, a bit, a bit stream, or other means that can be received, transmitted and/or detected.
Some portions of the detailed descriptions that follow are presented in terms of algorithms and symbolic representations of operations on data bits within a memory. These algorithmic descriptions and representations are used by those skilled in the art to convey the substance of their work to others. An algorithm, here and generally, is conceived to be a sequence of operations that produce a result. The operations include physical manipulations of physical quantities. Usually, though not necessarily, the physical quantities take the form of electrical or magnetic signals capable of being stored, transferred, combined, compared, and otherwise manipulated in a logic, and so on. The physical manipulations create a concrete, tangible, useful, real-world result.
As will be described further below, the pressure regulator 120 is configured to modulate a negative pressure to the ink to cause the ink to retrack or be drawn back away from the nozzles of the print head 105. The negative pressure serves to deprime the print head 105 so that any ink in the nozzles 105a will be pulled back into the print head 105. In this manner, ink does not remain in the nozzles 105a thereby reducing a possibility of the ink drying or crusting in the nozzles 105a caused by exposure to air. Since the ink is drawn back into the print head, the ink is not forced out of the nozzles as with other priming methods and thus the print head does not requiring cleaning due to leaking ink. In another embodiment, the pressure regulator 120 is further configured to modulate a pressure to re-prime the ejection chamber with ink.
In one embodiment, the example print head 105 can be implemented in high end printers or in ink printer cartridges. In high end printers, the ink reservoir 110 can be a separate and refillable reservoir. The printer 100 may include a blow prime port where the pressure regulator 120 is connected to apply the negative pressure through the blow prime port. In one embodiment, the blow prime port is formed through an ink cartridge housing to cause the print head 105 to be primed with ink. In a disposable cartridge printer system, the print head 105 and ink reservoir 110 are embodied in a replaceable ink cartridge. In the print cartridge system, the printer 100 may further comprise the controller 125 external to the cartridge where the controller 125 is configured to control the pressure regulator 120 that applies the negative pressure to the ink reservoir 110 within the cartridge.
In other embodiments, the printer 100 is more generally a fluid-jet precision-dispensing device that precisely dispenses fluid, such as ink, as is described in more detail later in the detailed description. The print head 105 may be a precision fluid ejector.
The printer 100 may eject pigment-based ink, dye-based ink, or another type of ink. Differences between pigment-based inks and dye-based inks can include that the former may be more viscous than the latter, among other differences. In these and other types of ink, the ink may be generally considered as having at least a liquid component, and may also have a solid component in the case of pigment-based inks in particular. The liquid component may be water, alcohol, and/or another type of solvent or other type of liquid, whereas the solid component may be pigment, or another type of solid.
In general, other embodiments pertain to any type of fluid-jet precision-dispensing device that dispenses a substantially liquid fluid. A fluid-jet precision-dispensing device is a drop-on-demand device in which printing, or dispensing, of the substantially liquid fluid is achieved by precisely printing or dispensing in accurately specified locations, with or without making a particular image on that which is being printed or dispensed on. As such, a fluid jet precision-dispensing device is in comparison to a continuous precision-dispensing device, in which a substantially liquid fluid is continuously dispensed therefrom. An example of a continuous precision-dispensing device is a continuous inkjet-printing device, for instance.
The fluid-jet precision-dispensing device precisely prints or dispenses a substantially liquid fluid in that the latter is not substantially or primarily composed of gases such as air. Examples of such substantially liquid fluids include inks in the case of inkjet-printing devices. Other examples of substantially liquid fluids include drugs, cellular products, organisms, fuel, and so on, which are not substantially or primarily composed of gases such as air and other types of gases, as can be appreciated by those of ordinary skill within the art. Therefore, while the following detailed description is described in relation to an inkjet-printing device that ejects ink onto media, other embodiments more generally pertain to any type of fluid-jet precision-dispensing device that dispenses a substantially liquid fluid.
In operation, the ink reservoir 110 will supply the ink channel 115 with ink. The ink will flow along the ink channel 115 to the ejection chamber 205. During a printing process, the ejection chamber 205 will eject ink through the nozzle 210. The ink may be ejected by heating the ink by a resister within the ejection chamber 205. When the ink has been heated to a high enough temperature and expanded, an ink drop is ejected from the nozzle 210. Alternatively, a mechanical system may be used within the ejection chamber 205 to eject ink through the nozzle 210. For example, applying a voltage to a piezoelectric material adjoining the ejection chamber 205 will expand that material and cause ink to be ejected from the ejection chamber 205.
When the printer 100 is not printing, the printer 100 may be partially de-primed. De-priming will extend the life of the print head 105 and can reduce the chances of the nozzle 210 and/or ejection chamber 205 from becoming clogged or coated with dried ink or other unwanted materials. De-priming involves removing ink from the nozzle 210 to reduce the exposure of the ink to air, which may cause the ink to dry out. In other embodiments, de-priming includes withdrawing ink from both the nozzle 210 and the ejection chamber 205.
In one embodiment, the ink may be drawn from the nozzle 210 and the ejection chamber 205 by creating a negative pressure on the ink within the printer 100. The controller 125 can be configured to control or signal the pressure regulator 120 to apply a negative pressure at a certain time or condition, for example, upon the printer 100 or ejection chamber 205 not ejecting ink for a predetermined time. This partially de-primes the fluid ejection device. The pressure regulator 120 will modulate a negative pressure to the ink to draw ink away from the nozzle 210 and the ejection chamber 205 and toward a high capillary force area 215. For example,
In one embodiment, the high capillary force area 215 may be within/part of the ink channel 115 upstream from the nozzle 210. Generally, the high capillary force area 215 has a higher capillary force than one or more other areas containing ink within the printer 100. In some embodiments, the high capillary force area 215 has a higher capillary force (e.g. greater force) than the nozzle 210 and has a higher capillary force than the ejection chamber 205. In other embodiments, the high capillary force area 215 is a pinch point in the ink channel 115 that is upstream from the ejection chamber 205 and the nozzle 210. For example, the pinch point has a cross sectional area less than a cross sectional area of the nozzle 210. Because the high capillary force area 215 has smaller area than the nozzle 210 and ejection chamber 205. In one embodiment, the high capillary force area 215 functions to stop air flow from depriming upstream of the high capillary force area 215.
The high capillary force area 215 is an area that creates capillary action of a liquid also known as wicking. Capillary action is the ability of a substance to draw another substance into it while replacing a third substance in the process. Capillary action occurs when the adhesive intermolecular forces between a liquid such as ink and the container holding the liquid are stronger than the cohesive intermolecular forces of the air and the container holding it. The effect causes a concave meniscus to form where the liquid substance is touching a surface. A high capillary force area 215 may be formed with a shape that creates a capillary force that prevents air from moving past the high capillary force area 215. Thus maintaining an ink channel 115 without air in it.
It may be beneficial to filter the ink before the ink reaches the ejection chamber 205. In some embodiments, the high capillary force area 215 includes a filter for filtering the ink before the ink enters the ejection chamber 205. The filter may also be placed upstream from the high capillary force area 215. The filter may include multiple filter channels where each filter channel has a smaller cross sectional area than the ink channel 115.
In one embodiment, each filter channel 305 functions as the high capillary force area 215 (e.g. pinch point) shown in
Example methods may be better appreciated with reference to flow diagrams. While for purposes of simplicity of explanation, the illustrated methodologies are shown and described as a series of blocks, it is to be appreciated that the methodologies are not limited by the order of the blocks, as some blocks can occur in different orders and/or concurrently with other blocks from that shown and described. Moreover, less than all the illustrated blocks may be required to implement an example methodology. Blocks may be combined or separated into multiple components. Furthermore, additional and/or alternative methodologies can employ additional, not illustrated blocks.
The method 400 continues, at 410, by applying a de-prime pressure to remove fluid from the plurality of nozzles. The de-prime pressure is a negative pressure that withdraws fluid from the nozzles back towards the fluid reservoir. In one embodiment, a sufficient negative pressure can be applied to withdraw the fluid back through the ejection chambers to a high capillary force area between the ejection chamber and the reservoir within the fluid channels. In one embodiment, a high capillary force area may be within each of the one or more fluid channels. The de-priming can extend the life of a print head by reducing the amount of time a fluid meniscus at a nozzle stays in contact with ambient air and thus reduces the possibility that the fluid dries out. In some embodiments, about negative 25-30 inches of water pressure is applied. Of course, other amounts of pressure can be used based on how much force is required for a particular fluid dispenser configuration.
At 520, a determination is made as to if a new fluid dispensing request (e.g. print request, dosage request, and so on) is pending that may require the operation of the fluid-jet dispensing device. If there is no new request, then the method 500 returns to step 515 to continue applying the de-prime pressure. If there is a new dispensing request, then, at 525, a re-prime pressure is applied. A re-prime pressure is a pressure that is a higher pressure than the de-prime pressure. For example, the re-prime pressure causes the fluid to flow back into each ejection chamber. In one embodiment, about negative 15 inches of water pressure is applied when applying the re-prime pressure. Of course, other amounts of pressure can be used based on how much pressure is required for a particular fluid jet dispensing device configuration.
In one example, a method may be implemented as computer executable instructions. Thus, one example, a computer-readable medium may store computer executable instructions that if executed by a machine (e.g., processor) cause the machine to perform a method to operate a printer that includes applying a de-prime pressure upon detecting that the printer has been idle for a predetermined time. While executable instructions associated with the above method are described as being stored on a computer-readable medium, it is to be appreciated that executable instructions associated with other example methods described herein may also be stored on a computer-readable medium.
Thus, de-prime logic 635 may provide means (e.g., hardware, stored software, firmware) for operating the fluid-jet dispensing device 625. The de-prime logic is configured to apply a de-prime pressure at selected times between fluid dispensing operations. As discussed earlier, the de-prime pressure withdraws fluid from the fluid ejection nozzles and/or the ejection chambers. The de-prime pressure may be applied upon the computer 600 detecting that the fluid-jet dispensing device 625 has been idle for a predetermined time.
The means may be implemented, for example, as an ASIC programmed to configured to facilitate applying a de-prime pressure upon detecting that the fluid jet dispensing device 625 has been idle for a predetermined time. The means may also be implemented as computer executable instructions that are presented to computer 600 as data 640 that are temporarily stored in memory 610 and then executed by processor 605.
De-prime logic 635 may also provide means (e.g., hardware, software, firmware) for applying a de-prime pressure upon detecting that the fluid-jet dispensing device 625 has been idle for a predetermined time.
Generally describing an example configuration of the computer 600, the processor 605 may be a variety of various processors including dual microprocessor and other multi-processor architectures. A memory 610 may include volatile memory and/or non-volatile memory. Non-volatile memory may include, for example, ROM, PROM, and so on. Volatile memory may include, for example, RAM, SRAM, DRAM, and so on.
A disk 645 may be operably connected to the computer 600 via, for example, the input/output interface (e.g., card, device) 630 and the input/output port 610. The disk 645 may be, for example, a magnetic disk drive, a solid state disk drive, a floppy disk drive, a tape drive, a Zip drive, a flash memory card, a memory stick, and so on. Furthermore, the disk 645 may be a CD-ROM drive, a CD-R drive, a CD-RW drive, a DVD ROM, and so on. The memory 610 can store a process 650 and/or a data 640, for example. The disk 645 and/or the memory 610 can store an operating system that controls and allocates resources of the computer 600.
The bus 620 may be a single internal bus interconnect architecture and/or other bus or mesh architectures. While a single bus is illustrated, it is to be appreciated that the computer 600 may communicate with various devices, logics, and peripherals using other busses. (e.g., PCIE, 1394, USB, Ethernet). The bus 620 can be types including, for example, a memory bus, a memory controller, a peripheral bus, an external bus, a crossbar switch, and/or a local bus.
The computer 600 may interact with input/output devices via the i/o interfaces 630 and the input/output ports 615. Input/output devices may be, for example, a keyboard, a microphone, a pointing and selection device, cameras, video cards, displays, the disk 645, the network devices 655, and so on. The input/output ports 615 may include, for example, serial ports, parallel ports, and USB ports.
The computer 600 can operate in a network environment and thus may be connected to the network devices 655 via the i/o interfaces 630, and/or the i/o ports 615. Through the network devices 655, the computer 600 may interact with a network. Through the network, the computer 600 may be logically connected to remote computers. Networks with which the computer 600 may interact include, but are not limited to, a LAN, a WAN, and other networks.
While example systems, methods, and so on have been illustrated by describing examples, and while the examples have been described in considerable detail, it is not the intention of the applicants to restrict or in any way limit the scope of the appended claims to such detail. It is, of course, not possible to describe every conceivable combination of components or methodologies for purposes of describing the systems, methods, and so on described herein. Therefore, the invention is not limited to the specific details, the representative apparatus, and illustrative examples shown and described. Thus, this, application is intended to embrace alterations, modifications, and variations that fall within the scope of the appended claims.
To the extent that the term “includes” or “including” is employed in the detailed description or the claims, it is intended to be inclusive in a manner similar to the term “comprising” as that term is interpreted when employed as a transitional word in a claim.
To the extent that the term “or” is employed in the detailed description or claims (e.g., A or B) it is intended to mean “A or B or both”. When the applicants intend to indicate “only A or B but not both” then the term “only A or B but not both” will be employed. Thus, use of the term “or” herein is the inclusive, and not the exclusive use. See, Bryan A. Gamer, A Dictionary of Modem Legal Usage 624 (2d. Ed. 1995).
To the extent that the phrase “one or more of, A, B, and C” is employed herein, (e.g., a data store configured to store one or more of, A, B, and C) it is intended to convey the set of possibilities A, B, C, AB, AC, BC, and/or ABC (e.g., the data store may store only A, only B, only C, A&B, A&C, B&C, and/or A&B&C). It is not intended to require one of A, one of B, and one of C. When the applicants intend to indicate “at least one of A, at least one of B, and at least one of C”, then the phrasing “at least one of A, at least one of B, and at least one of C” will be employed.
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/US2008/079828 | 10/14/2008 | WO | 00 | 3/17/2011 |
