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Publication numberUS3778222 A
Publication typeGrant
Publication dateDec 11, 1973
Filing dateSep 18, 1972
Priority dateSep 18, 1972
Publication numberUS 3778222 A, US 3778222A, US-A-3778222, US3778222 A, US3778222A
InventorsSuzuki K
Original AssigneeXerox Corp
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Fire prevention apparatus
US 3778222 A
Abstract
An apparatus in which an article passageway through a fusing device is closed to prevent a fire originating therein from spreading therefrom.
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Claims  available in
Description  (OCR text may contain errors)

Elnited States atent 1191 1111' 3,778,222 Suzuki Dec. 11, 1973 [54] FIRE PREVENTION APPARATUS 3,603,680 9/1971 Barton 355 3 3,650,616 3/1972 Hudson 355 3 [751 WWW: Y Japan 3,650,617 3/1972 Baxter et al. 355/3 I t d 3,705,289 12/1972 Szostak et al...... 250/65 ZE [73] Asslgnee Corporamm, S amfor 3,481,590 12/1969 Hovekamp 432/62 [22] Filed: Sept 1972 Primary Examiner-John .l. Camby 2 1 App) 290,013 Assistant Examiner-Henry C, Yuen AttorneyJames J. Ralabate et a1.

[52] US. Cl 432/35, 219/216, 432/59,

432/62 [57] ABSTRACT 2 gl An apparatus in which an article passageway through I l 'i"5535; 6 a fusing device is closed to prevent a fire originating j 3 therein from spreading therefrom.

6 The foregoing abstract is neither intended to define the invention disclosed in the specification, nor is it [56] References Cited intended to be limiting as to the scope of the invention UNITED STATES PATENTS any 3,697,722 10/1972 Furuichi et al. 219/216 10 Claims, 3 Drawing Figures PATENTEDUEBI 1 I975 SHEET 1 BF 2 FIG. I

FIG. 3

PATENTED DEC! 1 I975 SNEETZBFZ FIRE PREVENTION APPARATUS BACKGROUND OF THE INVENTION This invention relates generally to electrostatographic printing, and more particularly concerns an apparatus for preventing the spread of a fire originating in a fusing device used therein.

In electrostatographic printing, an image bearing member is charged to a substantially uniform level and, thereafter, selectively discharged to record thereon an electrostatic latent image corresponding to an original document to be reproduced. The latent image is developed or rendered viewable by depositing toner particles thereon. This toner powder image may be fused to the image bearing member, or in lieu thereof, transferred to a sheet of final support material and fused thereto. Generally, the toner particles are a heat settable colored thermoplastic powder. The toner particles electrostatically adhere to the image bearing member or final support material, and are passed through the fuser which generates heat of sufficient intensity to permanently fix the toner particles in image configuration thereon.

Various types of fusing devices are utilized in electrostatographic printing. Typical fusing devices utilize radiant heating elements for raising the temperature of the toner material to its set point. However, the temperature within the fusing device must be controlled to insure that excess heat is not generated therein. If the temperature exceeds the kindling temperature of the support material, which is typically plain paper, a fire may occur therein. This problem is common to most types of fusing devices utilized in electrostatographic printing. l-Ieretofore, a fire produced in the fusing device could rapidly spread throughout the remainder of the machine resulting in a great deal of damage and requiring extensive repairs. If the burning sheet were not contained within the machine it is possible for the flaming paper to be transported into the catch tray where it exposes the machine operator to injury, and the surrounding environment to potential damage.

Accordingly, it is a primary object of the present invention to improve the fire protection capability of fusing devices used in electrostatographic printing machines.

SUMMARY OF THE INVENTION Briefly stated and in accordance with the present invention, there is provided an apparatus for preventing the spread of a fire originating in a fusing device having an article passageway therethrough.

This is accomplished in the present instance by an apparatus including means for sensing the presence of the fire in the fusing device. When the fire is detected, means, responsive to the sensing means, enclose the passageway through the fusing device. Closing the passageway through the fusing device prevents the spread of the fire therefrom.

BRIEF DESCRIPTION OF THE DRAWINGS Other objects and advantages of the present invention will become apparent upon reading the following detailed description and upon reference to the drawings, in which:

FIG. 1 is a schematic perspective view of an electrophotographic printing machine embodying the features of the present invention;

FIG. 2 is an enlarged elevational view of a fusing device having the present invention incorporated therein; and

FIG. 3 is an enlarged fragmentary perspective view of a shutter member used in the present invention.

While the present invention will be described in connection with a preferred embodiment, it will be understood that it is not intended to limit the invention to that embodiment. On the contrary, it is intended to cover all alternatives, modifications and equivalents as may be included within the spirit and scope of the invention as defined by the appended claims.

DETAILED DESCRIPTION OF THE INVENTION With a continued reference to the drawings, wherein like reference numerals have been used throughout to designate like elements, FIG. 1 illustrates an electrophotographic printing machine for reproducing an original document. The electrophotographic printing machine depicted therein employs a rotatably mounted drum 10 having a photoconductive surface 12 thereon. Photoconductive surface 12 moves sequentially through a series of processing stations as drum 10 rotates in the direction of arrow 14.

A corona generating device, indicated at 16, is positioned at charging station A. Corona generating device 16 extends transversely across photoconductive surface 12 and charges surface 12 to a relatively high uniform potential. A suitable corona generating device is illustrated in U.S. Pat. No. 2,836,725 issued to Vyverberg in 1968.

Charged photoconductive surface 12 is, next, rotated to an exposure station B. Exposure station B includes a stationary lens system, designated generally at 18, and a scan lamp 20. Original document 22 is placed face down upon reciprocating platen 24 which moves in a generally horizontal plane as indicated by arrow 26. Platen 24 is transparent permitting scan lamp 20, disposed therebeneath, to illuminate incremental portions of original document 22 as it moves thereover. Light rays reflected from original document 22 irradiate photoconductive surface 12 to selectively dissipate the charge thereon and record an electrostatic latent image corresponding to original document 22.

Thereafter, drum 10 is rotated to development station C where the electrostatic laten image recorded on photoconductive surface 12 is rendered visible. Suitable development apparatus is arranged to deposit toner particles on the electrostatic latent image forming a powder image thereof. Typical development systems are cascade, magnetic brush or paddle wheel assemblies. Preferably, the present apparatus includes a paddle wheel arranged to fling the developer material over a guide member to cascade in a downwardly direction over the photoconductive surface to develop the latent image.

After development, the powder image electrostatically adheres to photoconductive surface 12 and advances therewith to transfer station D. Transfer corotron 28, disposed at transfer station D, attracts the toner powder image from photoconductive surface 12 to a sheet of final support material 30. Final support material 30 typically is a suitable plain paper.

Support material 30 with the powder image thereon is advanced by gripper bars 32 of an endless chain system to fixing station E having fusing device 34 positioned therein. Fuser 34 includes radiant heat elements, e.g. infrared lamps, and suitable control circuit means for maintaining the temperature thereof such that the toner powder image on final support material 30 is permanently adhered thereto. After the powder image is affixed to support material 30, gripper bars 32 move support material 30 to a pair of feed out rollers 36 which advance support material 30 to catch tray 38. In catch tray 38, final support material 30 may be readily removed therefrom by a machine operator.

Additional processing stations in the direction of rotation of drum 10, as indicated by arrow 14, are cleaning station F and discharge station G. Cleaning station F includes a web cleaning system 40 and a pre-clean corotron 42. Preclean corotron 42 applies a charge potential to photoconductive surface 12 which loosens or repels residual toner particles remaining thereon. This allows web cleaning system 40 to readily remove the toner particles therefrom. Any residual charge remaining on photoconductive surface 12 is, thereafter, removed at discharge station D. Discharge station D directs light rays from scan lamp onto photoconductive surface 12 intermediate web cleaning system 40 and corona generating device 16. The light rays dissipate the unwanted background potential remaining on photoconductive surface 12.

Each sheet of final support material is advanced by a sheet advancing mechanism utilizing a suitable reverse buckle type of sheet feeder. The sheet advancing mechanism is indicated generally at 44, and is arranged to move the sheet of final support material into the gripper bars which, in turn, transport the sheet to the transfer and fusing stations.

Referring now to FIGS. 2 and 3 there is illustrated, in detail, the fire prevention apparatus utilized in fusing device 34 depicted in FIG. 1. In the preferred embodiment, fusing device 34 includes an outer housing member 44 enclosing a pair of heating elements or infrared lamps 46. Gripper bars 32 advance sheet 30 in the direction of arrow 48. Enclosing means are provided at both the inlet and outlet of the passageway through the fusing device. The enclosing means includes a shutter member 50 mounted rotatably on pin 52 secured to the machine frame. Shutter member 50 is arranged to be of a length sufficient to close the entire outlet from the passageway. Side 54 of shutter member 50 is adapted to pivot in a downwardly direction so as to enclose the outlet from the passageway through fusing device 34. Shutter member 50 is maintained in the open position by an inelastic tension member such as a fusable wire 56 having one end thereof attached to shutter member 50 and passing through the fusing device and attached to the frame of the electrostatographic printing machine or, in lieu thereof, to the external surface of the fusing device itself. Micro switch 58 engages side 54 of shutter member 50 being in a closed position when shutter member 50 is in an open position, i.e. maintaining the passageway through fusing device 34 clear of any impediments. In operation, any fire within fusing device 34 severs fusible wire 56. After wire 56 parts, shutter member 50 pivots in a downwardly direction under the force of gravity to close the outlet opening of the passageway through the fusing device. As the shutter member pivots in the downwardly direction, side 54 disengages from microswitch 58 and microswitch 58 opens. When microswitch 58 is in the open position, the electrostatic printing machine is nonoperative. In this position, the gripper bars 32 can no longer advance the support material thus maintaining the burning support material within fusing device 34. In addition, opening ofmicroswitch 58 actuates an alarm indicating that there is a fire in fusing device 34.

While the present invention has been described such that gravity pivots shutte member 50 from the open to the closed position, it is'apparent that any suitable arrangement may be utilized. For example, biasing means such as a conventional spring member may be arranged to pivot shutter member 50 from the open to the closed position when a sensing means such as the fusible wire indicates the presence of a fire.

With reference to FIGS. 2 and 3, there is shown a shutter member 60 arranged to close the inlet to the passageway through fusing device 34. Shutter member 60 is rotatably mounted on pin 64 secured to cover 62. When shutter member 60 rotates under the force of gravity in the downwardly direction, side end portion 68 engages flat plate 66 secured to the frame of the printing machine thereby closing the inlet to the fuser passageway. Inextensible tension member or fusible wire 70 has one end thereof secured to projection 72 of shutter member 60. Fusible wire 70 extends transversely through fusing device 34 and passes through slots in members 74, 76 and 78, respectively attached to shutter member 60. One end of wire 70 is attached to microswitch 80. When wire 70 is severed by a flame, microswitch 80 is opened. In the open position, microswitch 80 de-energizes the printing machine.

In operation, shutter member 50 functions as a chute leading to paper catch tray 38 (FIG. 1). If the copy paper should start to burn, i.e., due to a paper jam occurring in fusing device 30 and the fire spreads toward the outlet side of fusing device 30, the flame cuts fusible wire 56. Thereafter, shutter member 50, which is rotatably mounted to the fusing device via pin 52 rotates under the force of gravity such that it contacts side surface 82 of fusing device 34 and closes the outlet side thereof. Simultaneously therewith, side 54 of shutter member 50 disengages from microswitch 58 causing the de-energization of the printing machine.

In the event that the fire spreads toward the inlet side of fusing device 34, fusible wire 70 extending transversely therethrough in the vicinity of the inlet is flame cut. Thereafter, shutter member 60, rotatably mounted on pin 64 and held in the open position by wire 70, pivots thereabout under the force of gravity until side 68 contacts flat plate 66 closing the inlet side of fusing device 34 to prevent the spread of the fire therefrom. Simultaneously therewith microswitch 80 opens so as to de-energize the printing machine.

In recapitulation, the present invention includes sensing means, i.e. fusible wires 56 and 70 arranged to detect the presence of a flame within fusing device 34. After the fire is detected, enclosure means, i.e. shutter members 50 and 60 close the outlet and inlet, respectively, to the passageway through fusing device 34 preventing the spread of the fire therefrom.

Thus, it is apparent that there has been provided in accordance with this invention an apparatus for preventing the spread of a fire from a fusing device that satisfies the objects, aims and advantages set forth above. While this invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications, and variations will be apparent to those skilled in the art in light of the foregoing description. Accordingly, it is intended to embrace all such alternatives, modifications and variations that fall within the spirit and broad scope of the appended claims.

What is claimed is:

1. An apparatus for preventing the spread of a fire originating in a fusing device having an article passageway therethrough, including:

means for sensing the presence of the fire in the fusing device; and

means, responsive to said sensing means indicating the fire in the fusing device, for enclosing the passageway through the fusing device to prevent the spread of the fire therefrom.

2. An apparatus as recited in claim 1, further including means for (lo-energizing the fusing device in response to said enclosing means moving to a position substantially closing the passageway through the fusing device.

3. An apparatus as recited in claim 1, wherein said enclosing means includes shutter members mounted movably on the fusing device and arranged to substantially close the entrance and exit of the passageway through the fusing device in response to said sensing means indicating a fire therein.

4. An apparatus for preventing the spread of a fire originating in a fusing device having an article passageway therethrough, including:

means for sensing the presence of the fire in the fusing device;

shutter members mounted movably on the fusing device and arranged to substantially close the entrance and exit of the passageway through the fusing device in response to said sensing means indicating a fire therein; and

biasing means for resiliently urging said shutter member to move in a direction substantially closing the entrance and exit of the passageway through the fusing device.

5. An apparatus as recited in claim 4, wherein said sensing means includes a fusible substantially inextensible tension memberextending through the fusing device and operatively connected at opposite ends thereof to said shutter members and the fusing device, respectively, restraining said shutter members from moving to a position substantially closing the entrance and exit of the passageway through the fusing device.

6. An electrostatographic printing machine of the type wherein a toner powder image of an original document to be reproduced is formed on a sheet of final support material, including:

a housing member having a passageway therethrough;

means for advancing the sheet of support material through the passageway in said housing member;

means for heating the toner powder image as the sheet of support material passes through the passageway in said housing member to permanently fix the powder image thereto;

means for sensing the presence of a fire in said housing member; and

means, responsive to said sensing member indicating a fire in said housing member, for enclosing the passageway in said housing member to prevent the spread of the fire therefrom.

7. A printing machine as recited in claim 6, further including means for de-energizing the printing machine in response to said enclosing means moving to a position substantially closing the passageway through said housing member.

8. A printing machine as recited in claim 6, wherein said enclosing means includes shutter members mounted movably on said housing member and arranged to substantially close the entrance and exit of the passageway through said housing member in response to said sensing means indicating a fire therein.

9. An electrostatographic printing machine of the type wherein a toner powder image of an original document to be reproduced is formed on a sheet of final support material, including:

a housing member having a passageway therethrough: means for advancing the sheet of support material through the passageway in said housing member;

means for heating the toner powder image as the sheet or support material passes through the passageway in said housing member to permanently fix the powder image thereto;

means for sensing the presence of a fire in said housing member;

shutter members mounted movably on said housing member and arranged to substantially close the entrance and exit of the passageway through said housing member in response to said sensing means indicating a fire therein; and

biasing means for resiliently urging said shutter member to move in a direction substantially closing the entrance and exit of the passageway through said housing member.

10. A printing machine as recited in claim 9, wherein said sensing means includes fusible substantially inextensible tension members extending through said housing member and operatively connected, at opposed ends thereof, to said shutter members and said housing member, respectively, restraining said shutter members from moving to a position substantially closing the entrance and exit of the passageway through said housing member.

Patent Citations
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US3481590 *Oct 15, 1968Dec 2, 1969Talcott Inc JamesFeeder means with heater
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US3650616 *Feb 1, 1971Mar 21, 1972Xerox CorpMispuff detector
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Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US4101266 *Jan 14, 1977Jul 18, 1978Tokyo Shibaura Electric Co., Ltd.Fire prevention device for the fixing stage of an electrophotographic machine
US4118178 *Jul 21, 1977Oct 3, 1978Pitney-Bowes, Inc.Xerographic fusing apparatus
US4341945 *Dec 31, 1979Jul 27, 1982Pitney Bowes Inc.Fire extinguishing device for electrophotocopier
US4367037 *Apr 1, 1981Jan 4, 1983Olympus Optical Company Ltd.Temperature controller for photographic heat fixing unit
US4402594 *Mar 22, 1982Sep 6, 1983Pitney Bowes Inc.Fire extinguishing device for electrophotocopier
US5732309 *Feb 19, 1997Mar 24, 1998Minolta Co., Ltd.Image forming apparatus
US8672469Sep 28, 2012Mar 18, 2014Ricoh Company, Ltd.Dryers that use rollers to define fire enclosure openings
US9310724 *Aug 27, 2014Apr 12, 2016Canon Kabushiki KaishaImage heating unit, recording medium conveying unit and image forming apparatus
US20150063868 *Aug 27, 2014Mar 5, 2015Canon Kabushiki KaishaImage heating unit, recording medium conveying unit and image forming apparatus
Classifications
U.S. Classification432/35, 219/216, 432/62, 399/33, 432/59, 392/417
International ClassificationG03G15/20
Cooperative ClassificationG03G15/2007
European ClassificationG03G15/20H1