CA1058273A - Radiant fuser for xerographic reproducing apparatus - Google Patents
Radiant fuser for xerographic reproducing apparatusInfo
- Publication number
- CA1058273A CA1058273A CA217,849A CA217849A CA1058273A CA 1058273 A CA1058273 A CA 1058273A CA 217849 A CA217849 A CA 217849A CA 1058273 A CA1058273 A CA 1058273A
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- CA
- Canada
- Prior art keywords
- energy
- radiant
- source
- shield
- sources
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
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- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 10
- 239000000758 substrate Substances 0.000 claims description 6
- 238000010438 heat treatment Methods 0.000 claims description 4
- 229920001721 polyimide Polymers 0.000 claims description 2
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- 229920001343 polytetrafluoroethylene Polymers 0.000 claims 1
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- 230000005855 radiation Effects 0.000 description 3
- 238000004140 cleaning Methods 0.000 description 2
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- 238000001816 cooling Methods 0.000 description 2
- 238000003384 imaging method Methods 0.000 description 2
- 238000009877 rendering Methods 0.000 description 2
- 239000004642 Polyimide Substances 0.000 description 1
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- HQQADJVZYDDRJT-UHFFFAOYSA-N ethene;prop-1-ene Chemical group C=C.CC=C HQQADJVZYDDRJT-UHFFFAOYSA-N 0.000 description 1
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- BFKJFAAPBSQJPD-UHFFFAOYSA-N tetrafluoroethene Chemical group FC(F)=C(F)F BFKJFAAPBSQJPD-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
- G03G15/00—Apparatus for electrographic processes using a charge pattern
- G03G15/20—Apparatus for electrographic processes using a charge pattern for fixing, e.g. by using heat
- G03G15/2003—Apparatus for electrographic processes using a charge pattern for fixing, e.g. by using heat using heat
- G03G15/2007—Apparatus for electrographic processes using a charge pattern for fixing, e.g. by using heat using heat using radiant heat, e.g. infrared lamps, microwave heaters
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Fixing For Electrophotography (AREA)
Abstract
RADIANT FUSER FOR XEROGRAPHIC REPRODUCING APPARATUS
ABSTRACT OF THE DISCLOSURE
Apparatus for heat fixing toner images electrostatically adhered to copy paper. The apparatus is characterized by the provision of plural radiant energy sources capable of fusing low density as well as high density images in an efficient manner. In order to prevent physical contact of the radiant energy sources by the copy paper, a shield is provided which is transparent to energy in the wave length bands required for fusing high and low density images.
ABSTRACT OF THE DISCLOSURE
Apparatus for heat fixing toner images electrostatically adhered to copy paper. The apparatus is characterized by the provision of plural radiant energy sources capable of fusing low density as well as high density images in an efficient manner. In order to prevent physical contact of the radiant energy sources by the copy paper, a shield is provided which is transparent to energy in the wave length bands required for fusing high and low density images.
Description
BACKGROUND OF THE INVENTION
This invention relates generally to electrostatographic copying apparatus and, more particularly, to radiant energy appara-tus for fixing toner images to a support member.
In the process of electrostatography, latent electro-static images are formed on a support member, for example, plain paper with the subsequent rendering of the latent images visible by the application of electroscopic marking particles, commonly referred to as toner. The toner or powder images so formed vary in density in accordance with the magnitude of electrostatic char-ges forming the individual images. The toner images can be fixed directly upon the support member on which they are formed or they may be transferred to another support member with subsequent fixing of the images thereto.
Fixing of toner images can be accomplished by various methods one of which is by the employment of thermal energy. In order to permanently fix or fuse toner images onto a support mem-ber by means of thermal energy it is necessary to elevate the tem-perature of the toner material to a point at which the constituents of the toner coalesce and become tacky or melt. This action causes the toner to be absorbed to some extent into the fibers of the paper. Thereafter as the toner cools, solidification of the toner material occurs causing it to be firmly bonded to the support member. In the process of electrostatography, the use of thermal energy for fixing toner images is old and well known.
One approach to thermal fusing of toner images onto a support member is to pass the support with the toner images there-on past a source of radiant energy such that the image bearing side of the support is opposite the source of radiation while the re~
verse side thereof is moved in contact with a heated platen. In ~)5~3273 the foregoing arrangement, for reasons understood by those skilled in the art, the radiant energy source is so constructed and func-tions such that it radiates energy at short wave lengths (i.e., 0.5-2.0 microns) which satisfactorily fuses high density images by means of the energy being directly absorbed by the toner. The heated platen provides thermal energy for elevating the temperature of the copy paper so that the paper does not act as a heat sink which would rob the toner images of heat provided by the radiant source. While the foregoing arrangement has been found to operate satisfactorily, it is possible for the low density images not to be fused satisfactorily due to either, the lack of intimate con-tact between the reverse side of the paper and the platen or the platen not being at the proper fusing temperature when the copy paper passes thereover. Moreover, in a duplex mode of operation the heated platen which operates above the softening point of the toner causes offsetting of toner to the platen.
BRIEF SUMM~RY OF THE INVENTION
In accordance with this invention there is provided apparatus for heat fuser toner images to a substrate on which they are supported, said apparatus comprising a first source of radiant energy capable of emitting energy having wave lengths on the order of 0.5-2.0 microns, a second source of radiant energy capable of emitting energy having wave lengt~s over 2.0 microns, means for transporting said substrate past said sources of radiant energy such that said toner images are directly c~. s~
exposed to said radiant sources, and ~a~s interpose~d between said radiant sources and said substrate, said ~e~ea2~-me~n~
being substantially transparent to the energy emitted from both of said energy sources.
In one embodiment of the invention the radiation sources comprise a quartz lamp which emits the short wave length energy and a reflector which absorbs energy emitted from the quartz lamp and re-radiates long wave length energy for heating the copy paper to ~hereby fuse the lower density images. As will be appreciated, the short wave length energy is directly absorbed by the toner images having a high density of toner particles.
In another embodiment of the invention, a resistance heater operating at a much lower surface temperature than the quartz lamp it is substituted for the reflector.
This invention will become more apparent from the detailed description to follow when read in conjunction with the accompanying drawings wharein:
DESCRIPTION OF THE DRAWINGS
_ Figure 1 is a schematic representation of a reproducing apparatus incorporating the invention;
Figure 2 illustrates a sectional view in elevation of a radiant fuser incorporated in the apparatus of Figure l;
Figure 3 illustrates a modified embodiment of the radiant fuser illustrated in Figure 2; and Figure 4 is a perspective view of a shield and support therefore incorporated in the fuser of Figures 2 and 3.
~5~Z~
DETAILED DESCRIPTION OF THE PREFERRED EMBODI~ENTS
Referring now to Figure 1, there is shown by way of example an automatic xerographic reproducing machine 1 which in-corporates the improved fusing apparatus 15 of the present inven-tion. The reproducing machine 1 depicted in Figure 1 illustrates the various components utilized therein for producing copies rom an original. Although the fusing apparatus 15 of the present in-vention is particularly well adapted for use in an automatic xero-graphic reproducing machine 1, it should become evident from the following description that it is equally well suited for use in a wide variety of machines where an image is fused to a sheet of final support material and it is not necessarily limited in its application to the particular embodiment shown herein.
The reproducing machine 1 illustrated in Figure 1 employs an image recording drum-like member 10 the outer periphery of which is coated with a suitable photoconductive material 11. One type of suitable photoconductive material is disclosed in U.S. Patent No.
This invention relates generally to electrostatographic copying apparatus and, more particularly, to radiant energy appara-tus for fixing toner images to a support member.
In the process of electrostatography, latent electro-static images are formed on a support member, for example, plain paper with the subsequent rendering of the latent images visible by the application of electroscopic marking particles, commonly referred to as toner. The toner or powder images so formed vary in density in accordance with the magnitude of electrostatic char-ges forming the individual images. The toner images can be fixed directly upon the support member on which they are formed or they may be transferred to another support member with subsequent fixing of the images thereto.
Fixing of toner images can be accomplished by various methods one of which is by the employment of thermal energy. In order to permanently fix or fuse toner images onto a support mem-ber by means of thermal energy it is necessary to elevate the tem-perature of the toner material to a point at which the constituents of the toner coalesce and become tacky or melt. This action causes the toner to be absorbed to some extent into the fibers of the paper. Thereafter as the toner cools, solidification of the toner material occurs causing it to be firmly bonded to the support member. In the process of electrostatography, the use of thermal energy for fixing toner images is old and well known.
One approach to thermal fusing of toner images onto a support member is to pass the support with the toner images there-on past a source of radiant energy such that the image bearing side of the support is opposite the source of radiation while the re~
verse side thereof is moved in contact with a heated platen. In ~)5~3273 the foregoing arrangement, for reasons understood by those skilled in the art, the radiant energy source is so constructed and func-tions such that it radiates energy at short wave lengths (i.e., 0.5-2.0 microns) which satisfactorily fuses high density images by means of the energy being directly absorbed by the toner. The heated platen provides thermal energy for elevating the temperature of the copy paper so that the paper does not act as a heat sink which would rob the toner images of heat provided by the radiant source. While the foregoing arrangement has been found to operate satisfactorily, it is possible for the low density images not to be fused satisfactorily due to either, the lack of intimate con-tact between the reverse side of the paper and the platen or the platen not being at the proper fusing temperature when the copy paper passes thereover. Moreover, in a duplex mode of operation the heated platen which operates above the softening point of the toner causes offsetting of toner to the platen.
BRIEF SUMM~RY OF THE INVENTION
In accordance with this invention there is provided apparatus for heat fuser toner images to a substrate on which they are supported, said apparatus comprising a first source of radiant energy capable of emitting energy having wave lengths on the order of 0.5-2.0 microns, a second source of radiant energy capable of emitting energy having wave lengt~s over 2.0 microns, means for transporting said substrate past said sources of radiant energy such that said toner images are directly c~. s~
exposed to said radiant sources, and ~a~s interpose~d between said radiant sources and said substrate, said ~e~ea2~-me~n~
being substantially transparent to the energy emitted from both of said energy sources.
In one embodiment of the invention the radiation sources comprise a quartz lamp which emits the short wave length energy and a reflector which absorbs energy emitted from the quartz lamp and re-radiates long wave length energy for heating the copy paper to ~hereby fuse the lower density images. As will be appreciated, the short wave length energy is directly absorbed by the toner images having a high density of toner particles.
In another embodiment of the invention, a resistance heater operating at a much lower surface temperature than the quartz lamp it is substituted for the reflector.
This invention will become more apparent from the detailed description to follow when read in conjunction with the accompanying drawings wharein:
DESCRIPTION OF THE DRAWINGS
_ Figure 1 is a schematic representation of a reproducing apparatus incorporating the invention;
Figure 2 illustrates a sectional view in elevation of a radiant fuser incorporated in the apparatus of Figure l;
Figure 3 illustrates a modified embodiment of the radiant fuser illustrated in Figure 2; and Figure 4 is a perspective view of a shield and support therefore incorporated in the fuser of Figures 2 and 3.
~5~Z~
DETAILED DESCRIPTION OF THE PREFERRED EMBODI~ENTS
Referring now to Figure 1, there is shown by way of example an automatic xerographic reproducing machine 1 which in-corporates the improved fusing apparatus 15 of the present inven-tion. The reproducing machine 1 depicted in Figure 1 illustrates the various components utilized therein for producing copies rom an original. Although the fusing apparatus 15 of the present in-vention is particularly well adapted for use in an automatic xero-graphic reproducing machine 1, it should become evident from the following description that it is equally well suited for use in a wide variety of machines where an image is fused to a sheet of final support material and it is not necessarily limited in its application to the particular embodiment shown herein.
The reproducing machine 1 illustrated in Figure 1 employs an image recording drum-like member 10 the outer periphery of which is coated with a suitable photoconductive material 11. One type of suitable photoconductive material is disclosed in U.S. Patent No.
2~970,906 issued to Bixby in 1961. The drum 10 is suitab]y jour-naled for rotation within a machine frame (not shown) by means of a shaft 12 and rotates in the direction indicated by arrow 13, to bring the image retaining surface thereon past a plurality of xerographic processing stations. Suitable drive means (not shown) are provided to power and coordinate the motion of the various cooperating machine components whereby a faithful reproduction of the original input scene information is recorded upon a sheet 14 of final support material such as paper or the like.
Since the practice of xerography is well-known in the art, the various processing stations for producing a copy of an original are herein represented in Figure 1 as blocks A to E.
Initially, the drum 10 moves photoconductive surface 11 through 1~5~273 charging station A. At charging station A an electrostatic charge is placed uniformly over the photoconductive surface 11 of the drum 10 preparatory to imaging. The charging may be provided by a corona generating device of a type described in U.S. Patent No. 2,836,725 issued to Vyverberg in 1958.
Thereafter, the drum 10 is rotated to exposure station B where the charged photoconducti~e surface 11 is ex-posed to a light image of the origi 1 input scene information, whereby the charge is selectively dissipated in the light exposed regions to record the original input scene in the form of a latent electrostatic image. A suitable exposure system may be the type described in U.S. Patent ~o. 3,832,057, issued August 27, 1974, D.K. Shogren.
After exposuref drum 10 rotates the electrostatic latent image recorded on the photoconductive surface 11 to development station C wherein a conventional developer mix is applied to the photoconductive surface 11 of the drum 10 rendering the latent image visible. A suitable development station is disclosed in Canadian Patent Application, Serial No. 145,905 filed June 28, 1972. The application describes a magnetic brush development system utilizing magnetizable developer mix having carrier granules and toner colorant. The developer mix is continuously brought through a directional flux field to form a brush thereof. The electrostatic latent image recorded on photoconductive surface 11 is developed by bringing the brush of developer mIx into contack therewith.
The devoloped image on the photoconductive surface 11 is then brought into contact with a sheet 14 of final ~51~3Z73 support material within a transfer station D and the toner image is transferred from the photoconductive surface 11 to the contacting side of the final support sheet 14. The final support material may be paper, plastic, etc., as desired.
After the toner image has been transferred to the sheet of final support material 14, the sheét with,the image thereon is advanced to a fuser assembly 15, which fixes the transfer-red powdered image thereto. After the fusing process, the sheet 14 is advanced through a snuffing apparatus 2 then by rolls 16 to a catch tray 17 for subse~uent removal therefrom by the machine operator.
Although a preponderence of the toner powder is transferred to the final support material 14, invariably some residual toner remains on the photoconductive surface 11 ater the transfer of the toner powder image to the final support material 14. The residual toner particles remaining on the photoconductive surface 11 after the transfer operation are removed from the drum 10 as it moves through cleaning station E. Here the residual toner particles are first brought under the influence of a cleaning coron~ generating d~vice ~not shown) adapted to neutralize the electrostatic charge remaining on the toner particles. The neutralized - toner particles are than mechanically cleaned fr~m the photo-conductive surface 11 by conventional means as for example the use of a resiliently biased knife blade as set forth in U.S. Patent No. 3,660,863 issued to Gerbasi in 1972.
If desired, in accordance with the invention, the sheets 14 of final support material processed in the automa-~ _7_ ~(~58Z73 tic xerographic reproducing device can be stored in themachine within a removable paper cassette 18. A suitable paper cassette is set forth in Canadian Patent Application, Serial No. 148,892 filed August 8, 1972.
The reproducing apparatus in accordance with this invention can also have the capability of ~ccepting and pro-cessing copy sheets 14 of varying lengths. The length of the copy sheet 14, of ' -7a-~D"S~
course, being dictated by the size of the original input scene or infoxmation recorded on the photoconductive surface 11. To this end the paper cassette 18 is preferably provided with an adjust-able feature whereby sheets of varying length and width can be conveniently accommodated. In operation the cassette 18 is filled with a stack of final support material 19 of pre-selected size and the cassette 18 is inserted into the machine by sliding along a base plate (not shown) which guides the cassette into operable re-lationship with a pair of feed rollers 20. When properly positioned in communication with the feed rollers 20, the top sheet of the stack 19 is separated and forwarded from the stack 19 into the transfer station D by means of registration rolls 21.
It is believed that the foregoing description is suffi-cient for purposes of the present application to illustrate the general operation of the automatic xerographic reproducing machine 1 which can embody the teachings of the present invention.
Referring now to Figure 2, that portion of the reproduc-ing machine 1 of Figure 1 embodying the fusing apparatus 15 of this invention is shown in greater detail. The image bearing sheet 14 after passing through the transfer station D of Figure 1 upon separation from the photoconductive surface 11 is allowed to fall into contact with a vacuum belt transport system 22 which conveys the sheet directly to the fusing station 15.
The fusing station 15 comprises a radiant type fuser.
The fusing station 15 comprises a heated platen 30 mounted to en-gage the non-image bearing side of the copy sheet 14 which moves in sliding contact therewith as it is transported through the fusing zone. The heated platen 30 is designed so that an efficient heat flow is established between the platen and the copy sheet 14 to raise the temperature of the sheet rapidly to a level somewhat below the sheet's scorch temperature. By controlling the tempera-ture of the sheet 14 in this manner the ability of the sheet to act as a heat sink during image fixing is minimized.
The radiant energy for fusing is provided by an infrared S quartz lamp 31 which is mounted in a reflector assembly 32 in oppos-ing relationship to the hea~ed platen 30 and in a position to ther-mally communicate with the image side of the copy sheet 14. The operating temperature of the lamp is on the order of 2400K. Pre-ferably the spectral output of the lamp 31 is within a range at which the imaging material which may be toner for a xerographic machine 1 is highly absorptive and at which the support material 14 which may be paper is relatively non-absorptive. As a result, the toner images are rapidly raised to the desired fusing tempera-ture while the support sheet 14 remains at a relatively lower tem-perature. A forced air cooling chamber 33 is provided about the backside of the reflector assembly 32 to cool the fuser 15 in operation.
A heating element 34 i9 provided in the platen 30 to maintain it at the desired temperature during standby periods.
When the quartz lamp 31 is operated the preheat element is dis-connected and the platen 30 receives its heat input directly from the quartz lamp.
The reflector assembly 32 is so constructed that it both reflects the short wave length energy emitted from the quartz lamp 31 and absorbs the long wave length energy with the subsequent re-radiation thereof, the temperature of the reflector being on the order of 1000K. To this end the reflector 32 is a low mass con-struction and an air insulating barrier is provided between the reflector and the cooling chamber 33. The re-radiated long wave length energy is effective to raise the temperature of the paper 14 ._ g _ to thereby assist the heating element 34 in providing the energy necessary for fusing low density images. It will be appreciated that the reflected short wave length energy is absorbed by -the high density images to thereby effect fusing thereof.
A shield assembly 50 as best illustrated in Figure 4 is provided to preclude physical contacting of the quartz lamp 31 and the reflector 32 by the copy paper 14. The assembly 50 comprises a radiant energy transparent film 51 which has a thickness on the order of 5 mils. Typical materials which are useful as a film such as 51 are tetrafluoroethylene, flourinated ethylene-propylene and polyimide polymers. The film 51 is attached to a pair of frame or support members 52 and 53 the former of which is provided with a pair of pins 54 which are received in recesses or bores 55 of the frame member 53. This arrangement allows relative movement of the frame members by virtue of a pair of bias members in the form of coil springs 56. Temperature variations of the film will cause it to sag, consequently, the specific construction of the shield assembly provides for a constant planar orientation of the film over the operating temperatures of the fuser 15.
The frame members each have a flange 57 which is received in one of a pair of opposed recesses 58 provided in the reflector assembly 32. The space between the bottoms of the recesses 58 is such as to allow for relative movement of the frame members in a horizontal direction.
In the modified embodiment of the fuser assembly 15, illustrated in Figure 3, the source of long wave length radia-tion is provided by means of a resistance heater 59 operated at a tem-perature on the order of 1000K which may be fabricated from any suitable material, for example, nicrom wire.
While the invention has been described with respect to - \
two preferred embodiments it will be apparent that certai.n modi-fications and changes can be made without departing from the spirit and the scope of the invention and it is therefore intended that the foregoing disclosure be limited only by the claims ap-pended hereto.
Since the practice of xerography is well-known in the art, the various processing stations for producing a copy of an original are herein represented in Figure 1 as blocks A to E.
Initially, the drum 10 moves photoconductive surface 11 through 1~5~273 charging station A. At charging station A an electrostatic charge is placed uniformly over the photoconductive surface 11 of the drum 10 preparatory to imaging. The charging may be provided by a corona generating device of a type described in U.S. Patent No. 2,836,725 issued to Vyverberg in 1958.
Thereafter, the drum 10 is rotated to exposure station B where the charged photoconducti~e surface 11 is ex-posed to a light image of the origi 1 input scene information, whereby the charge is selectively dissipated in the light exposed regions to record the original input scene in the form of a latent electrostatic image. A suitable exposure system may be the type described in U.S. Patent ~o. 3,832,057, issued August 27, 1974, D.K. Shogren.
After exposuref drum 10 rotates the electrostatic latent image recorded on the photoconductive surface 11 to development station C wherein a conventional developer mix is applied to the photoconductive surface 11 of the drum 10 rendering the latent image visible. A suitable development station is disclosed in Canadian Patent Application, Serial No. 145,905 filed June 28, 1972. The application describes a magnetic brush development system utilizing magnetizable developer mix having carrier granules and toner colorant. The developer mix is continuously brought through a directional flux field to form a brush thereof. The electrostatic latent image recorded on photoconductive surface 11 is developed by bringing the brush of developer mIx into contack therewith.
The devoloped image on the photoconductive surface 11 is then brought into contact with a sheet 14 of final ~51~3Z73 support material within a transfer station D and the toner image is transferred from the photoconductive surface 11 to the contacting side of the final support sheet 14. The final support material may be paper, plastic, etc., as desired.
After the toner image has been transferred to the sheet of final support material 14, the sheét with,the image thereon is advanced to a fuser assembly 15, which fixes the transfer-red powdered image thereto. After the fusing process, the sheet 14 is advanced through a snuffing apparatus 2 then by rolls 16 to a catch tray 17 for subse~uent removal therefrom by the machine operator.
Although a preponderence of the toner powder is transferred to the final support material 14, invariably some residual toner remains on the photoconductive surface 11 ater the transfer of the toner powder image to the final support material 14. The residual toner particles remaining on the photoconductive surface 11 after the transfer operation are removed from the drum 10 as it moves through cleaning station E. Here the residual toner particles are first brought under the influence of a cleaning coron~ generating d~vice ~not shown) adapted to neutralize the electrostatic charge remaining on the toner particles. The neutralized - toner particles are than mechanically cleaned fr~m the photo-conductive surface 11 by conventional means as for example the use of a resiliently biased knife blade as set forth in U.S. Patent No. 3,660,863 issued to Gerbasi in 1972.
If desired, in accordance with the invention, the sheets 14 of final support material processed in the automa-~ _7_ ~(~58Z73 tic xerographic reproducing device can be stored in themachine within a removable paper cassette 18. A suitable paper cassette is set forth in Canadian Patent Application, Serial No. 148,892 filed August 8, 1972.
The reproducing apparatus in accordance with this invention can also have the capability of ~ccepting and pro-cessing copy sheets 14 of varying lengths. The length of the copy sheet 14, of ' -7a-~D"S~
course, being dictated by the size of the original input scene or infoxmation recorded on the photoconductive surface 11. To this end the paper cassette 18 is preferably provided with an adjust-able feature whereby sheets of varying length and width can be conveniently accommodated. In operation the cassette 18 is filled with a stack of final support material 19 of pre-selected size and the cassette 18 is inserted into the machine by sliding along a base plate (not shown) which guides the cassette into operable re-lationship with a pair of feed rollers 20. When properly positioned in communication with the feed rollers 20, the top sheet of the stack 19 is separated and forwarded from the stack 19 into the transfer station D by means of registration rolls 21.
It is believed that the foregoing description is suffi-cient for purposes of the present application to illustrate the general operation of the automatic xerographic reproducing machine 1 which can embody the teachings of the present invention.
Referring now to Figure 2, that portion of the reproduc-ing machine 1 of Figure 1 embodying the fusing apparatus 15 of this invention is shown in greater detail. The image bearing sheet 14 after passing through the transfer station D of Figure 1 upon separation from the photoconductive surface 11 is allowed to fall into contact with a vacuum belt transport system 22 which conveys the sheet directly to the fusing station 15.
The fusing station 15 comprises a radiant type fuser.
The fusing station 15 comprises a heated platen 30 mounted to en-gage the non-image bearing side of the copy sheet 14 which moves in sliding contact therewith as it is transported through the fusing zone. The heated platen 30 is designed so that an efficient heat flow is established between the platen and the copy sheet 14 to raise the temperature of the sheet rapidly to a level somewhat below the sheet's scorch temperature. By controlling the tempera-ture of the sheet 14 in this manner the ability of the sheet to act as a heat sink during image fixing is minimized.
The radiant energy for fusing is provided by an infrared S quartz lamp 31 which is mounted in a reflector assembly 32 in oppos-ing relationship to the hea~ed platen 30 and in a position to ther-mally communicate with the image side of the copy sheet 14. The operating temperature of the lamp is on the order of 2400K. Pre-ferably the spectral output of the lamp 31 is within a range at which the imaging material which may be toner for a xerographic machine 1 is highly absorptive and at which the support material 14 which may be paper is relatively non-absorptive. As a result, the toner images are rapidly raised to the desired fusing tempera-ture while the support sheet 14 remains at a relatively lower tem-perature. A forced air cooling chamber 33 is provided about the backside of the reflector assembly 32 to cool the fuser 15 in operation.
A heating element 34 i9 provided in the platen 30 to maintain it at the desired temperature during standby periods.
When the quartz lamp 31 is operated the preheat element is dis-connected and the platen 30 receives its heat input directly from the quartz lamp.
The reflector assembly 32 is so constructed that it both reflects the short wave length energy emitted from the quartz lamp 31 and absorbs the long wave length energy with the subsequent re-radiation thereof, the temperature of the reflector being on the order of 1000K. To this end the reflector 32 is a low mass con-struction and an air insulating barrier is provided between the reflector and the cooling chamber 33. The re-radiated long wave length energy is effective to raise the temperature of the paper 14 ._ g _ to thereby assist the heating element 34 in providing the energy necessary for fusing low density images. It will be appreciated that the reflected short wave length energy is absorbed by -the high density images to thereby effect fusing thereof.
A shield assembly 50 as best illustrated in Figure 4 is provided to preclude physical contacting of the quartz lamp 31 and the reflector 32 by the copy paper 14. The assembly 50 comprises a radiant energy transparent film 51 which has a thickness on the order of 5 mils. Typical materials which are useful as a film such as 51 are tetrafluoroethylene, flourinated ethylene-propylene and polyimide polymers. The film 51 is attached to a pair of frame or support members 52 and 53 the former of which is provided with a pair of pins 54 which are received in recesses or bores 55 of the frame member 53. This arrangement allows relative movement of the frame members by virtue of a pair of bias members in the form of coil springs 56. Temperature variations of the film will cause it to sag, consequently, the specific construction of the shield assembly provides for a constant planar orientation of the film over the operating temperatures of the fuser 15.
The frame members each have a flange 57 which is received in one of a pair of opposed recesses 58 provided in the reflector assembly 32. The space between the bottoms of the recesses 58 is such as to allow for relative movement of the frame members in a horizontal direction.
In the modified embodiment of the fuser assembly 15, illustrated in Figure 3, the source of long wave length radia-tion is provided by means of a resistance heater 59 operated at a tem-perature on the order of 1000K which may be fabricated from any suitable material, for example, nicrom wire.
While the invention has been described with respect to - \
two preferred embodiments it will be apparent that certai.n modi-fications and changes can be made without departing from the spirit and the scope of the invention and it is therefore intended that the foregoing disclosure be limited only by the claims ap-pended hereto.
Claims (7)
1. Apparatus for heat fuser toner images to a substrate on which they are supported, said apparatus comprising:
a first source of radian-t energy capable of emitting energy having wave lengths on the order of 0.5-2.0 microns;
a second source of radiant energy capable of emitting energy having wave lengths over 2.0 microns;
means for transporting said substrate past said sources of radiant energy such that said toner images are directly exposed to said radiant sources; and a shield interposed between said radiant sources and said substrate, said shield being substantially transparent to the energy emitted from both of said energy sources.
a first source of radian-t energy capable of emitting energy having wave lengths on the order of 0.5-2.0 microns;
a second source of radiant energy capable of emitting energy having wave lengths over 2.0 microns;
means for transporting said substrate past said sources of radiant energy such that said toner images are directly exposed to said radiant sources; and a shield interposed between said radiant sources and said substrate, said shield being substantially transparent to the energy emitted from both of said energy sources.
2. Apparatus according to Claim 1, wherein said first source of energy comprises a quartz lamp and said second source comprises a reflector for re-radiating long wave length energy therefrom.
3. Apparatus according to Claim 1, wherein said first source comprises a quartz lamp and said second source comprises a resistance heating element having an operating temperature sub-stantially less than said first source.
4. Apparatus according to Claim 3, wherein said shield comprises a polytetrafluoroethylene film on the order of 5 mils in thickness.
5. Apparatus according to Claim 4, including expansible means for mounting said shield in a substantially planar orienta-tion regardless of the temperature thereof.
6. Apparatus according to Claim 5, wherein said expan-sible means is supported by depending flanges of reflector means associated with said energy sources.
7. Apparatus according to Claim 3, wherein said shield comprises a 5 mil thick polyimide film.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US446192A US3898424A (en) | 1974-02-25 | 1974-02-25 | Radiant fuser for xerographic reproducing apparatus |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1058273A true CA1058273A (en) | 1979-07-10 |
Family
ID=23771652
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA217,849A Expired CA1058273A (en) | 1974-02-25 | 1975-01-09 | Radiant fuser for xerographic reproducing apparatus |
Country Status (4)
| Country | Link |
|---|---|
| US (1) | US3898424A (en) |
| CA (1) | CA1058273A (en) |
| GB (1) | GB1478216A (en) |
| NL (1) | NL7500940A (en) |
Families Citing this family (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3987757A (en) * | 1974-11-18 | 1976-10-26 | Xerox Corporation | Paper handling improvements in radiant fuser via corrugation of paper |
| JPS52130334A (en) * | 1976-04-26 | 1977-11-01 | Fuji Xerox Co Ltd | Fixing apparatus for copying machine |
| US4355225A (en) * | 1981-03-30 | 1982-10-19 | Xerox Corporation | Instant-on radiant fuser |
| CN85100700A (en) * | 1985-04-01 | 1987-01-31 | 陆伯祥 | Computing machine Moire fringe certificate and recognition system thereof |
| US4724303A (en) * | 1986-08-06 | 1988-02-09 | Xerox Corporation | Instant-on fuser |
| US4883941A (en) * | 1986-08-06 | 1989-11-28 | Xerox Corporation | Filament wound foil fusing system |
| US4778980A (en) * | 1986-10-06 | 1988-10-18 | Xerox Corporation | Instant-on fuser control |
| US5872350A (en) * | 1997-11-21 | 1999-02-16 | Xerox Corporation | Paper fire Preventer |
| DE10064561A1 (en) * | 2000-12-22 | 2002-06-27 | Nexpress Solutions Llc | Fixing device for fixing toner material |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3449546A (en) * | 1966-06-23 | 1969-06-10 | Xerox Corp | Infra-red heater |
| US3452181A (en) * | 1967-12-27 | 1969-06-24 | Eastman Kodak Co | Roll fusing device for xerographic material |
| US3811828A (en) * | 1970-10-29 | 1974-05-21 | Ricoh Kk | Process and device for heating and fixing an image upon a recording medium |
| JPS5350442Y2 (en) * | 1971-08-19 | 1978-12-02 |
-
1974
- 1974-02-25 US US446192A patent/US3898424A/en not_active Expired - Lifetime
-
1975
- 1975-01-09 CA CA217,849A patent/CA1058273A/en not_active Expired
- 1975-01-27 NL NL7500940A patent/NL7500940A/en unknown
- 1975-02-06 GB GB512075A patent/GB1478216A/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| US3898424A (en) | 1975-08-05 |
| GB1478216A (en) | 1977-06-29 |
| NL7500940A (en) | 1975-04-29 |
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