Heating in the temperature range of approximately 100° C. (210° F.) to 600° C. (1,110° F.) is required for a large number of processes used in industrial, commercial, and residential settings. A large number of heat producing devices have been developed to supply thermal energy for these processes, the bulk of which use conventional resistance (Ohmic) or inductive circuits. One example of an apparatus that uses this type of heat producing device is the photocopy machine.
Referring to
Methods and devices in accordance with the invention utilize heat generated by the absorption of microwave energy through incorporation of carbon nanotechnologies. In one embodiment, microwave radiation may be used to heat carbon nanotubes embedded in an elastomer coating of an image reproduction device's roller mechanism.
Referring to
In the illustrated embodiment, elastomer 205 and 215 may be a fluoroelastomer (a special purpose fluorocarbon-based synthetic rubber). Fluoroelastomers are a class of elastomers comprising copolymers of hexafluoropropylene (H FP) and vinyl idene fluoride (VDF or VF2), terpolymers of tetrafluoroethylene (TFE), vinylidene fluoride (VDF) and hexafluoropropylene (HFP). In general, fluoroelastomers exhibit a wide chemical resistance, especially in high temperature applications. One illustrative fluroelastomer is Viton® 6000. (VITON is a registered trademark of DuPont Dow Elastomers).
In one embodiment, elastomer coatings 205 and 215 are substantially the same. That is, they comprise the same elastomer material and are loaded (i.e., embedded or include) the same weight percentage of nanotube material. (As used herein, the phrase “X weight-percentage” means that if the total weight of the elastomer material—including nanotube material—applied to a roller is Y, X % of that is attributable to carbon nanotube material.) In another embodiment, each roller 210 and 220 may use a different composition of elastomer and/or a different loading of nanotube material. In still another embodiment, the pressure roller may not require heating and, therefore, not include or incorporate carbon nanotube material or waveguide launcher 230. One of ordinary skill in the art will recognize the specific decision regarding these issues depends upon the desired design goals of the particular image reproduction device being constructed. Nevertheless, given the information of this disclosure and the background and knowledge of one of ordinary skill in the art, these decisions would be possible without undue experimentation.
Referring to
The type of carbon nanotubes that may be used to load the elastomer material applied to fuser roller 210 and pressure roller 220 may be multi-walled, functionalized multi-walled, raw single walled and purified single walled nanotubes, buckytubes, fullerene tubes, carbon fibrils, carbon nanotubes, stacked cones, horns, carbon nanofibers, vapor-grown carbon fibers, and combinations thereof. In addition, the nanotube material used may be chemically functionalized in a variety of manners. Carbon nanotubes used in this invention can be made by any known technique (e.g., arc method, laser oven, chemical vapor deposition, flames, HiPco, etc.) and can be in a variety of forms, e.g., soot, powder, fibers, “bucky papers,” etc. It is further noted that the use of pristine, unmodified nanotubes with unperturbed sidewall (which have a higher microwave cross-section of absorbance) can reduce the wt-% of carbon nanotube material needed.
In general, the elastomer coating used should be thick enough to incorporate or contain sufficient nanotube material that it can absorb substantially all of the applied microwave radiation. One of ordinary skill in the art will also recognize that the overall thickness and texture (its ability to nip material fed to it) of a roller's elastomer coating may also be affected by other design parameters such as operating speed, type of material being processed (e.g., paper or plastic) and the like.
As commonly used, the term microwave radiation refers to electromagnetic radiation having frequencies in the range of 0.3 GHz and 300 GHz. The more prevalent frequency used in microwave ovens is 2.54 GHz, which is also a common frequency for heating carbon nanotubes. Waveguide launchers 225 and 230 are metal, metal alloy or metal composite enclosures that direct microwave radiation towards elastomer coated rollers 210 and 220. Within device 200, one or more microwave generators 235 may be used to supply energy to waveguide launchers 225 and 230 through, for example, coaxial cable coupled at points A and B.
Microwave power may be continuous or pulsed. The surface temperature of rollers 210 and 220 may be controlled by changing the time, frequency, power or a combination of time/frequency and power of the microwave source. For example, microwave generator 235 may have a variable output with a range of 0-120 watts; however a higher wattage output may be required depending on the application. The pulse duration may be varied from, for example, 1 to 1,000 microseconds and the pulse repetition frequency from 2 to 1,000 pulses per second. In one embodiment, microwave generator/source 235 may be used to produce pulsed power to maintain a steady-state temperature at the surface of roller 210 and roller 220. Generator 235 can increase pulse duration, pulse repetition frequency or operate in continuous mode depending on the roller temperature requirement. In general, the roller surface temperature requirement is established by the requirements of the colorant or toner and the operating speed or the image reproduction device.
It will be understand that the basic principle of heating carbon nanotube material embedded in a roller to heat material is not limited to use in an image reproduction device. One of ordinary skill in the art would recognize that there are many processes that require the use of a heated roller; laminating, embossing, drying, annealing, calendering, and film orientation to name just a few. In these embodiments, the material being processed or heated may be paper, film, plastic, rubber, film and the like. Each of these processes may benefit from the use of embedding carbon nanotube material in, on or proximate to the surface of a roller, heating that material with microwave radiation, and transferring the absorbed microwave energy (in the form of heat) to a surface moved across the surface of the roller in accordance with the invention.
In the interest of clarity, not all features of an actual implementation are described in this specification. It will of course be appreciated that in the development of any such actual implementation (as in any hardware development project), numerous decisions must be made to achieve the developers' specific goals (e.g., compliance with system- and business-related constraints), and that these goals will vary from one implementation to another. It will be appreciated that such development effort might be complex and time-consuming, but would nevertheless be a routine undertaking for those of ordinary skill having the benefit of this disclosure. For example, while the decision of what type, energy production capability and operating mode (e.g., continuous, pulsed or mixed) the microwave source should be is a complex one, it would nevertheless be a routine engineering decision based on, for example, the type of toner and colorants used, the desired speed of operation and the expected or designed duty-cycle of the image reproduction device.
This application claims priority to U.S. provisional patent application 61/043,629 entitled “Heating of Copy Machine Fusing Roller by Carbon Nanotube Absorption of Microwave Radiation” (filed 9 Apr. 2008). This application is also related to the following provisional patent applications: 61/093,776 entitled “Microwave Heating Using Carbon Nanotechnology” (filed 3 Sep. 2008) and 61/106,694 entitled “A Novel Infrared (IR) Heater to Reduce Energy Consumption While Maintaining Thermal Quality for Personnel Working in a Commercial Building Environment” (filed 20 Oct. 2008). Each of these applications are hereby incorporated by reference.
Number | Date | Country | |
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61043629 | Apr 2008 | US | |
61093776 | Sep 2008 | US | |
61106694 | Oct 2008 | US |