Patent Grant
7140724
The present invention relates to imaging apparatus-and methods for homogenizing ink.
A wide variety of imaging apparatus and printing devices are used to produce printed materials. Such printing equipment typically includes an ink delivery system which functions to deliver liquid ink from an ink supply to one or more printheads. The printheads then apply the ink to an imaging media.
One popular type of printing apparatus are the ink-jet printers. Ink-jet printers are widely used as a means of producing high quality printing. A typical ink-jet printer includes an ink delivery system which delivers ink to one or more printheads. Each of these printheads generally has several nozzles which function to eject ink during the printing process.
As a popular printing apparatus, ink-jet printers are used in a variety of settings, and are subjected to a range of operating conditions and demands. For example, some ink-jet printers are used frequently, while others are used rarely and thus experience extended idle times. Some ink-jet printers remain stationary in an office or home, while others are transported to various locations where they are used to perform printing functions. Ink-jet printers are subjected to a variety of environmental conditions, which may include, but are not limited to, extreme temperatures, varying degrees of humidity, air-borne pollutants, direct sun-light and frequent movement. As a result of these diverse use patterns and operating conditions, ink-jet printers operate under a variety of environmental conditions. One situation that may result from long idle times or varying environmental conditions is a thickening of the ink within the printhead due to fluid loss (i.e., vaporization or migration of the carrying fluid used to transport the ink pigments), which can cause poor print quality or printhead failure. To accommodate these diverse use patterns and operating conditions, it is desirable to develop printing apparatus which will satisfy such demands.
Imaging apparatus and methods of homogenizing ink are described. The embodiments disclosed herein are for illustrative purposes and should not be construed as limiting the invention.
In one implementation an imaging apparatus is described. The imaging apparatus includes an ink supply which provides ink to be used in printing, and a printhead which applies the ink during printing. A conduit system couples the ink supply and the printhead in fluid flowing relation. A pump is operably coupled to the conduit system. In operation, the pump causes the ink to circulate between the ink supply and the printhead. A timing device measures an idle-time since the pump was last in operation. A controller receives the idle-time measurement from the timing device, and actuates the pump when a selected idle-time is reached.
In another implementation, a method for homogenizing ink is described. The method includes providing a pump, then automatically actuating the pump to homogenize ink within an ink delivery system each time the ink delivery system has been resting for a selected idle-time.
Imaging apparatus such as ink-jet printers typically include an ink delivery system which functions to deliver ink from an ink supply or reservoir to one or more printheads. In the context of this document, the term “imaging apparatus” refers to any apparatus which uses ink to generate an image on an imaging media, such as paper or the like. Examples of imaging apparatus include, without by way of limitation, printers, copiers, facsimile machines, and other devices which use ink from a reservoir to apply an image onto imaging media. The term “ink” refers to any liquid medium which can be used for printing, including both water-based and non-water-based inks. Such inks typically comprise dissolved colorants or pigments dispersed in a solvent. In a typical ink-jet printer, printheads are used to apply the ink to an imaging media.
When an ink delivery system in an imaging apparatus, such as an ink-jet printer, remains idle for an extended period of time, print quality can degrade as volatile components such as water, or any other volatile components, are lost from the ink.
Imaging apparatus that do not periodically recirculate or otherwise homogenize the ink can develop regions of ink from which the volatile components have been depleted. In such regions, the ink can become too viscous to be adequately pumped or fully cleared from the system, causing image quality defects or other printing problems or failures. In addition, imaging apparatus that do not periodically homogenize the ink may suffer print quality problems when the concentration of ink in the printhead has moved outside of acceptable limits due to the -loss of volatile components from the ink. In some cases remediation of such problems requires that the printhead be replaced or primed.
In other cases, clogging can occur as volatile components are lost from the ink. Such clogging typically occurs in areas of the ink delivery system which have a small resident ink mass, such as small diameter tubes, or in areas such as the printheads. Because the rate of loss of volatile components from the ink and resident ink mass vary by component, it is advantageous to periodically mix the ink in the system to homogenize the concentration. In the context of this document, the terms “homogenize” and “homogenization” refer to a mixing or circulation (including recirculation) of the ink within the ink delivery system and printhead to decrease potential problems such as image quality defects and clogging.
Imaging apparatus that recirculate ink for a given amount of time before a print job, without recirculating the ink during long idle periods between print jobs, may not adequately homogenize the ink because a clog can occur during the long idle-time. Imaging apparatus which continuously recirculate ink consume large amounts of energy due to the continuous pumping required.
For these and other reasons, it is desirable to develop imaging apparatus, ink delivery systems and methods for homogenizing ink which will help to prevent the degradation of print quality and clogging. Moreover, it is desirable to develop methods and apparatus which will accomplish these objectives in a convenient and efficient manner. It is also desirable that such methods and apparatus be applicable to portable imaging devices. While the present invention is principally directed towards overcoming the above identified issues, the invention is in no way so limited, and is only limited by the accompanying claims as literally worded and appropriately interpreted in accordance with the Doctrine of Equivalents.
Referring to
Referring to
If the imaging apparatus 200 is used with a computer (not shown), the computer can function as the controller 224 and the timing device 222. For example, the computer can cause the pump 220 to be actuated when a selected idle-time is reached. In addition, the computer can cause the pump 220 to be actuated to homogenize the ink 212 at any selected time. By way of example only, the computer can actuate the pump 220 at 2:00 a.m. (or any other selected time) when the pumping process is least likely to interrupt business activities.
In one variation, the pump 220 is reversible and in operation intermittently reverses its pumping action to facilitate homogenization of the ink 212. That is, the pump 220 can first pump ink from the printhead 214 to the ink supply 210, and then reverse to pump ink from the ink supply 210 to the printhead 214 (or vis-a-versa). The reversing of the pump can be controlled by the controller 224. The use of any suitable pump is contemplated, for example in one embodiment the pump 220 is a peristaltic pump. Other types of pumps can also be used such as, without by way of limitation, a centrifugal pump or a positive displacement pump. When the pump 220 is a peristaltic pump, then a section of the conduit 216 can be a flexible segment (not shown, but generally within pump 220), and the pump can include a moveable member (also not shown) which can be moved along a portion of the flexible segment to thereby urge ink in the flexible segment to move in the direction of the moveable member.
In another variation, a battery 230 is electrically coupled to the pump 220 by a battery path 231. In operation, the battery 230 powers the pump 220. The battery 230 allows the pump 220 to function without an external power source. In other variations, the pump 220 can be powered by another power source (not shown), such as the power source which is used by the ink-jet printer 205 for normal printing operations. Additionally, the pump 220 can be configured to be driven primarily by the power source which is used by the ink-jet printer 205 for normal printing operations, and, when the printer 205 is disconnected from such a power source, to use the battery 230 as a power source.
Referring again to
In another variation, a smart-chip 250 is operably coupled to the ink supply 210. By way of example, and not by way of limitation, the smart-chip can be electronic memory, ROM, EEPROM, or battery backed RAM. The smart-chip 250 is encoded with pump-time parameters. In the context of this document, the term “pump-time parameters” is defined to mean any information regarding the ink, the pump, environmental conditions, and/or operating conditions which can affect the pumping used to homogenize the ink. By way of example only, pump-time parameters can include, but are not limited to, information regarding the type of ink, the age of ink, and the volume of ink. As other examples, the pump-time parameters can include information such as the pump-rate (i.e., the number of pump revolutions per minute), the pump-time (i.e., the duration of time the pump operates to complete a print job), and the selected idle-time (i.e., the duration of idle-time allowed before the pump is automatically triggered to run). The smart-chip 250 is electrically coupled to the controller 224 by smart-chip path 251. The controller 224 receives signals from the smart-chip 250 to facilitate homogenization of the ink. These signals from the smart-chip 250 aid the controller 224 in determining what pumping will adequately homogenize the ink 212. It will be appreciated that the smart-chip 250 and the controller 224 can be combined into a single unit.
Referring still to
In one variation the sensor 254 is configured to measure a humidity level. In another variation the sensor 254 is configured to measure a temperature. The sensor 254 can be configured to measure any environmental condition which can affect homogenization of the ink 212, and the measurement of any and all such environmental conditions is contemplated by the present invention. Further, two or more such sensors 254 can be used in combination to measure two or more such environmental conditions.
In one variation on the present embodiment of the invention, the ink delivery system 206 includes a smart-chip 250 encoded with pump-time parameters. The smart-chip 250 is operably coupled to the ink supply 210, and is electrically coupled to the controller 224 by smart-chip path 251. The controller 224 receives the pump-time information from the smart-chip 250. The controller 224 then generates, based at least in part upon the pump-time information, a control signal to the pump 220 to thereby manage homogenization of the ink 212. In another variation the pump-time information includes data regarding an ink type. In yet another variation the pump-time information includes data regarding an ink volume. In still a further variation the pump-time information includes data regarding an ink age. The smart-chip 250 can include any pump-time data that is useful in managing homogenization of the ink 212, and the inclusion of any and all such pump-time information is contemplated by the present invention.
Referring now to
The use of any suitable pump 320 is contemplated, for example in one variation the pump 320 is a peristaltic pump. As described above with respect to pump 220 of
Referring again to
The conduit system 316 includes a supply conduit 345 which couples the primary ink supply 335 and the secondary ink supply 336 in fluid flowing relation. In operation the supply conduit 345 facilitates a flow of ink 312 from the primary ink supply 335 to the secondary ink supply 336. The conduit system 316 also includes a return conduit 346 which couples the secondary ink supply 336 and the primary ink supply 335 in fluid flowing relation. In operation the return conduit 346 facilitates a flow of ink from the secondary ink supply 336 to the primary ink supply 335. As the ink 312 circulates or recirculates through the conduit system 316, the ink is homogenized. When the pump 320 is a peristaltic pump, then a section (not shown, but generally within pump 320) of the supply conduit 345, and a section (also not shown, but generally within pump 320) of the return conduit 346 can be flexible segments. In this case the pump 320 can include first and second moveable members (not shown). The first moveable member can be moved along the flexible segment of the supply conduit 345 to thereby urge ink in the supply conduit to move in the direction of the first moveable member. Likewise, the second moveable member can be moved along the flexible segment of the return conduit 346 to thereby urge ink in the return conduit to move in the direction of the second moveable member. The first and second moveable members can be attached to a common rotating shaft such that simultaneous pumping of ink in the supply and return conduits 345, 346 occurs.
In one variation, a smart-chip 350 is operably coupled to the ink supply 310. The smart-chip 350 is encoded with pump-time parameters. The smart-chip 350 is electrically coupled to the controller 324 by smart-chip path 351. The controller 324 receives signals from the smart-chip 350 to facilitate homogenization of the ink. As indicated above with respect to smart-chip 250, the smart-chip 350 can be, for example, electronic memory, ROM, EEPROM, battery backed RAM, or other computer readable memory.
Referring now to
Referring once again to
In one variation, the ink-jet printer 305 also includes a sensor 354 to measure an environmental condition which affects homogenization of the ink 312. The sensor 354 is electrically coupled to the controller by sensor signal path 355. The controller 324 is configured to receive the environmental measurement from the sensor 354, and based at least in part upon the environmental measurement, the controller 324 intermittently actuates the pump 320 for a duration adequate to homogenize the ink 312. In another variation, the ink-jet printer 305 includes a battery 330 electrically coupled to the pump 320. In operation the battery 330 powers the pump 320, and in operation the battery 330 also powers the ink-jet printer 305. The battery 330 allows both the pump 320 and the ink-jet printer 305 to function without an external power source.
Referring again to
Referring again to
A further embodiment of the invention provides for a method of homogenizing ink in an ink delivery system, such as ink delivery systems 206 and 306 of respective
Yet another embodiment of the present invention provides a method for homogenizing ink which includes the step of providing an ink supply (such as ink supplies 210, 310 of respective
It will be appreciated that the ink supplies 210, 310 (
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As depicted in
At step 404 (
If at step 404 (
One or more of the pump-time parameters can be stored in the smart chip 250, 350 which is operably coupled to the ink supply 210, 310 (shown in respective
Other methods consistent with the present invention can also be performed. While the exemplary methods described above with respect to flowchart 400 recite respective steps and orders of execution, it is to be understood that other suitable methods including other steps and/or orders of execution can also be used. While the above methods and apparatus have been described in language more or less specific as to structural and methodical features, it is to be understood, however, that they are not limited to the specific features shown and described, since the means herein disclosed comprise preferred forms of putting the invention into effect. The methods and apparatus are, therefore, claimed in any of their forms or modifications within the proper scope of the appended claims appropriately interpreted in accordance with the Doctrine of Equivalents.
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