Universal voltage fuser heater lamp

Information

  • Patent Grant
  • 6614008
  • Patent Number
    6,614,008
  • Date Filed
    Friday, December 14, 2001
    22 years ago
  • Date Issued
    Tuesday, September 2, 2003
    20 years ago
Abstract
A universal voltage fuser heater lamp is described for use in either United States or European markets having different voltage standards. The fuser lamp comprises first and second filaments having equal resistance and a switching mechanism for connecting a power supply to the fuser lamp. The switching mechanism connects the first and second filaments in a parallel configuration when the voltage is 120 Volts and connects the first and second filaments in series when the voltage is 240 Volts from the power supply.
Description




FIELD OF INVENTION




The present invention relates generally to tubular incandescent lamps, and pertains, more particularly, to such lamps as applied in photo-reproduction processes.




BACKGROUND OF THE INVENTION




A photocopy machine typically employs two different types of lamps, one being referred to as an exposure lamp and the other as a fusing lamp. The exposure lamp is purely for light emitting purposes during the exposure phase of operation. The fusing lamp on the other hand is primarily for heating purposes to “set” the toner employed in the photocopy machine. In accordance with the present invention, the principles thereof are applied primarily in connection with a fusing heater lamp, but may also be applied to other general heating purposes.




Fusing heater lamps are typically of single filament construction and have a length corresponding to the maximum size (length) of paper that is to be reproduced. More recently, fusing heater lamps utilize two filaments disposed and electrically connected in parallel within a quartz envelope in order to allow substantially higher operating wattage to be achieved by simultaneously energizing both filaments. The use of parallel filaments provides higher heat density per unit area of envelope wall. However, these types of fuser heater lamps do not provide for selective activation of the filaments to adjust for different voltage output requirements.




Photocopier's used in both the United States and Europe operate at two different voltage ranges, namely 120 and 240 volts respectively, but each require the same amount of energy in the fuser lamp for fixing the toner (i.e. fusing) onto the copy of the original document. In U.S. Pat. No. 4,710,676 to Morris et al, a dual length filament incandescent lamp is provided that allows for switching between two different levels of total lamp energy at a single voltage to adjust for different incremental wattage output requirements. The specification of Morris et al (U.S. Pat. No. 4,710,676) is hereby incorporated by reference.




What would be desirable is a single tubular incandescent lamp without modification that can run on two different voltage ranges for heating applications for universal that use different voltage standards.




SUMMARY OF THE INVENTION




It is, therefore, a primary object of this invention to enhance the tubular incandescent lamp art and particularly that art involving lamps having more than one filament.




It is another object of this invention to provide an improved incandescent lamp wherein the lamp is readily adapted for use in either United States or European markets having different voltage standards.




In accordance with one aspect of this invention, there is provided a fuser lamp comprising first and second filaments having equal resistance and a switching mechanism for connecting a power supply to the fuser lamp. The switching mechanism connects the first and second filaments in a parallel configuration when the voltage is 120 Volts and connects the first and second filaments in series when the voltage is 240 Volts from the power supply.











BRIEF DESCRIPTION OF THE DRAWINGS




The objects, features and advantages of the invention will become apparent upon consideration of the following detailed disclosure of the invention, especially when it is taken in conjunction with the accompanying drawings wherein:





FIG. 1

is a side view, partly in section of a lamp illustrating the electrical switching control of the instant invention; and





FIGS. 2A-2B

is an electrical circuit schematic illustrating switch states of the instant invention; and





FIGS. 3A-3C

are side views, partly in section, illustrating different lamp configuration embodiments for use with the electrical switching control of the instant invention.











DETAILED DESCRIPTION OF THE INVENTION




Referring to

FIG. 1

there is shown a side view, partly in section of a fuser lamp


10


illustrating the electrical switching control or switching mechanism of the instant invention. In one embodiment of the invention, the electrical switching control or switch mechanism is a double-pole double-throw switch


40


defining a pair of first and second switches. As shown in

FIG. 1

, a power supply


38


delivers voltage to the fuser lamp


10


through the switch


40


. It should be understood that the configuration and description of lamp


10


is for illustrative purposes only wherein any suitable fuser lamp may be used in association with the present invention. The lamp


10


comprises a tubular envelope


12


of vitreous material having first and second press-sealed end portions


14


and


16


, respectively. Ends


14


and


16


are located at the opposed ends of envelope


12


and are formed by utilizing pressing operations and apparatus known in the art. Envelope


12


should preferably be made of a material having a high melting point, such as fused silica or quartz.




Lamp


10


is of the tungsten-halogen variety, therefore it has a fill gas mixture containing an inert gas and a halogen or halide. In the present invention, the lamps are filled at about one atmosphere of argon (as the inert gas) and have about 200 micrograms of bromine (specifically methyl bromide). Lamp


10


further includes a pair of tungsten filaments,


18


and


20


, which are disposed within envelope


12


and extend longitudinally through the interior of the envelope. Filaments


18


and


20


, as illustrated in

FIG. 1

, are electrically isolated from one another by isolating means, comprising two tubes,


22


and


24


, that are disposed longitudinally within envelope


12


. Filaments


18


and


20


extend longitudinally through tubes


22


and


24


, respectively. Tubes


22


and


24


should be made of electrically insulative material that is transparent and has a high melting point, such as quartz. Tubes


22


and


24


extend the length of the interior of envelope


12


to about 1 millimeter (mm) from press sealed end portions


14


and


16


. The filaments are also hermetically sealed within end portions


14


and


16


.




Supporting filaments


18


and


20


at preselected points (about 25.4 mm apart) along the length thereof are a plurality of support members


26


(illustrated in FIG.


1


), each comprising a coil element having one end wound about (and thus secured to) each of filaments


18


and


20


and the other end (of greater diameter) positively engaging the interior wall of tubes


22


and


24


, respectively. In the embodiment illustrated in

FIG. 1

, filaments


18


and


20


possessed an overall length of about 350 mm. In addition, envelope


12


is a T-5 quartz tube having an outer diameter of about 15 mm with a thickness of about 1 mm. Tubes


22


and


24


are T-2 quartz tubes having outer diameters of about 6 mm and thicknesses of about 1 mm.




To facilitate positioning of lamp


10


within the photocopier designed for utilizing same, ceramic bases or end caps


28


and


30


are preferably used. Accordingly, it is only necessary in the respective photocopier to provide some means for accepting this component. Understandably, such a means can be of relatively simple design. Ceramic bases


28


and


30


are also preferably of substantially cylindrical configuration and include a slot therein designed for having the flattened press-sealed end portions,


14


and


16


, inserted therein.




Filaments


18


and


20


are energized by means of applying a predetermined voltage across contact means located within the press sealed end portions of lamp


10


. Specifically, first contact means


32


is associated with end portion


14


, while second contact means


34


and third contact means


36


are associated with end portion


16


. First contact means


32


is comprised of a first lead-in conductor


32




a,


which extends externally from and internally within end portion


14


, and a foil portion


32




b


disposed within portion


14


and electrically coupled to both conductor


32




a


and to a first end


18




a


and


20




a


of filaments


18


and


20


, respectively. Second contact means


34


is comprised of a second lead-in conductor


34




a,


which extends externally from and internally within end portion


16


, and a foil portion


34




b


disposed within portion


16


and electrically coupled to both conductor


34




b


and to a second end


18




b


of filament


18


. Finally, third contact means


36


is comprised of a third lead-in conductor


36




a,


extending externally from and internally within end portion


16


, and a foil portion


36




b


disposed within end portion


16


and electrically coupled to both conductor


36




a


and to an unattached second end


20




b


of filament


20


.




Referring once again to

FIG. 1

, the terminals


56


and


58


of power supply


38


are coupled to the input side of first and second switches


66


and


68


respectively, of the double-pole double-throw switch


40


. Lead-in conductor


32


is coupled to a lead wire


50


, which is in turn coupled to the output side of first switch


66


. Lead-in conductor


34


is coupled to a lead wire


52


, which is in turn coupled to the output side of switch


68


and lead-in conductor


36


is coupled to a lead wire


54


, which is in turn coupled to the input side of switch


68


. Leads


50


,


52


and


54


may in one embodiment be stranded 16 AWG (AWG=American Wire Gauge) teflon insulated wire which is rated at 600 V and 200° C. Lead wires


50


,


52


and


54


, through switch


40


apply a voltage across filaments


18


and


20


. In accordance with the present invention, fuser heater lamps such as lamp


10


are broken into two regions wherein each region is represented as a filament, each at 120 volts. When the fuser is operated at 120 volts, the regions are connected in parallel and when operated at 240 volts, they are connected in series.




Referring now to

FIGS. 2A-2B

, there is shown electrical circuit schematics illustrating the two different switch states.

FIG. 2A

illustrates the parallel connection when the first and second switches


66


and


68


of the double-pole double-throw switch


40


are in the up position. In this state the lead wires


52


and


54


of filaments


18


and


20


are connected in parallel through terminal


56


when lead wire


50


is connected to terminal


58


.

FIG. 2B

illustrates the series connection when the first and second switches


66


and


68


of the double-pole double-throw switch


40


are in the down position. In this state the lead wires


52


and


54


of filaments


18


and


20


are connected in series through terminals


56


and


58


when lead wire


50


is in an open state. The filaments


18


and


20


have the same value of resistance such that the fuser lamp


10


with the switching means in accordance with the present invention may be universally connected to power supplies in either the United States and European markets.




Turning once again to

FIG. 1

, the double-pole double-throw switch


40


is positioned such that filaments


18


and


20


are in series and therefore in the 240 Volt configuration. By way of example but not of limitation, for a fuser lamp


10


to operate at 1000 Watts and using Ohm's law the resistance per filament is calculated as follows:







R=E




2




/P






where:




R=DC resistance in Ohms;




P=Power in Watts;




E=Voltage in Volts;




for a 1000 Watt fuser lamp operating in the United States at 120 Volts:








R




120V


=120


2


Volts/1000 Watts










R




120V


=14.4 Ohms;






and for a 1000 Watt fuser lamp operating in Europe at 240 Volts:








R




240V


=240


2


Volts/1000 Watts










R




240V


=57.6 Ohms.






Referring to

FIG. 2A

, for the 120 Volt arrangement the elements of resistance are arranged in parallel and are calculated using R


120V


=R


120V


×n where n is the number of elements. In this case the number of elements n or filaments is 2 such that R


120V


=14.4 Ohms×2=28.8 Ohms. Referring to

FIG. 2B

, for the 240 Volt arrangement the elements of resistance are arranged in series and are calculated using R


240V


=R


240V


/n where n is once again the number of elements (n=2) corresponding to filaments


18


and


20


, respectively. In this case, R


240V


=57.6 Ohms/2=28.8 Ohms. Therefore, by using filaments


18


and


20


each having a resistance of 28.8 Ohms a fuser lamp having a 1000 Watt output may be used in either the United States or Europe using the switching means in accordance with the present invention. As seen by the example, the resistances of a two-filament fuser lamp must be equal in order to switch between two different voltage standards.





FIGS. 3A-3C

are side views, partly in section, illustrating different lamp configuration embodiments for use with the electrical switching control of the instant invention.

FIG. 3A

illustrates a dual envelope lamp as described above.

FIG. 3B

illustrates a single envelope lamp wherein

FIG. 3C

is a single envelope lamp having a single center tapped filament. All the lamps of

FIGS. 3A-3C

are similar with respect to filament lengths and wattages, fill gas mixture, overall lamp length, lead wire connections and lamp-circuit connection with each having lead wires


50


,


52


and


54


for use with the present invention. Additionally, although not shown any switching means may be used in lieu of a double-pole double-throw switch, such as an electronic switch that attains the desired effect of switching the filaments to a series or parallel arrangement.




While there have been shown and described what are at present considered embodiments of the invention, it will be obvious to those skilled in the art that various changes and modifications may be made therein without departing from the scope of the invention as defined by the appended claims.



Claims
  • 1. A voltage fuser heater lamp comprising:a power supply for delivering voltage; a fuser lamp having first and second filaments; and a switching mechanism for connecting the power supply to the fuser lamp wherein the switching mechanism connects the first and second filaments in a series configuration in one state and connects the first and second filaments in parallel configuration in another state depending on the voltage from the power supply.
  • 2. The voltage fuser heater lamp of claim 1, wherein the first and second filaments of the fuser lamp have equal resistance.
  • 3. The voltage fuser heater lamp of claim 1, wherein the switching mechanism is a double-pole double-throw switch.
  • 4. The voltage fuser heater lamp of claim 1, wherein the switching mechanism is an electronic switch.
  • 5. The voltage fuser heater lamp of claim 1, wherein the fuser lamp is a dual envelope configuration.
  • 6. The voltage fuser heater lamp of claim 1, wherein the fuser lamp is a single envelope configuration.
  • 7. The voltage fuser heater lamp of claim 1, wherein the fuser lamp is a single envelope with center taped filament configuration.
  • 8. The voltage fuser heater lamp of claim 1, wherein the power supply delivers 120 Volts and the switch mechanism connects the first and second filaments in parallel.
  • 9. The voltage fuser heater lamp of claim 1, wherein the power supply delivers 240 Volts and the switch mechanism connects the first and second elements in series.
  • 10. A voltage fuser heater lamp comprising:a power supply for delivering voltage; a fuser lamp having first and second filaments wherein the first and second elements have equal resistance; and a switching mechanism for connecting the power supply to the fuser lamp wherein the switching mechanism connects the first and second filaments in a series configuration in one state and connects the first and second filaments in a parallel configuration in another state depending on the voltage from the power supply.
  • 11. The voltage fuser heater lamp of claim 10, wherein the switching mechanism is a double-pole double-throw switch.
  • 12. The voltage fuser heater lamp of claim 10, wherein the switching mechanism is an electronic switch.
  • 13. The voltage fuser heater lamp of claim 10, wherein the fuser lamp is a dual envelope configuration.
  • 14. The voltage fuser heater lamp of claim 10, wherein the fuser lamp is a single envelope configuration.
  • 15. The voltage fuser heater lamp of claim 10, wherein the fuser lamp is a single envelope with center taped filament configuration.
  • 16. The voltage fuser heater lamp of claim 10, wherein the power supply delivers 120 Volts and the switch mechanism connects the first and second filaments in parallel.
  • 17. The voltage fuser heater lamp of claim 10, wherein the power supply delivers 240 Volts and the switch mechanism connects the first and second elements in series.
  • 18. A voltage fuser heater lamp comprising:a power supply for delivering voltage; a fuser lamp having first and second filaments wherein the first and second elements have equal resistance; and a switching mechanism for connecting the power supply to the fuser lamp wherein the switching mechanism connects the first and second filaments in a parallel configuration when the voltage is 120 Volts and connects the first and second filaments in series when the voltage is 240 Volts from the power supply.
  • 19. The voltage fuser heater lamp of claim 18, wherein the switching mechanism is a double-pole double-throw switch.
  • 20. The voltage fuser heater lamp of claim 18, wherein the switching mechanism is an electronic switch.
US Referenced Citations (17)
Number Name Date Kind
1716645 Kuen Jun 1929 A
1722002 Kuen et al. Jul 1929 A
1802167 Blank Apr 1931 A
3272977 Holmes Sep 1966 A
3443144 Freese May 1969 A
3791710 Curtis Feb 1974 A
4442374 Morris et al. Apr 1984 A
4488082 Cummins Dec 1984 A
4598342 English et al. Jul 1986 A
4621220 Morris et al. Nov 1986 A
4626735 Morris et al. Dec 1986 A
4710676 Morris et al. Dec 1987 A
5053806 Haigo et al. Oct 1991 A
5091632 Hennecke et al. Feb 1992 A
5455484 Maya et al. Oct 1995 A
5493379 Kuroda et al. Feb 1996 A
5922227 McMurtrie Jul 1999 A