US4243869A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Fusing device for electrostatic copier
Assignee: Pitney Bowes Inc
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Filing: 1979-05-16
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Granted: 1981-01-06
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Expires: 1999-05-16
Abstract
Abstract A fusing apparatus for an electrostatic copier has a flexible web rotatably driven between first and second pressure fixing rollers that are further supported by a rotatable, third pressure roller substantially in contact with the web and the second pressure fixing roller. Only the web is heated in an area just prior to the first pressure fixing roller. The entrapped copy sheet follows a concave path formed by the web and the first pressure fixing roller outer diameter, during which time the toner is gradually melted until it is finally pressed and fixed on the copy sheet by the first and second pressure fixing rollers.
Inventors
- 👤 Albert W. Scribner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 23:45
CPC Classifications
G; G03; G03G; G03G15/00; G03G15/20; G03G15/2003; G03G15/2014; G03G15/2064
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
221 words
A fusing apparatus for applying pressure and heat to an unfused copy sheet bearing a developed electrostatic image on at least one surface thereof in order to fuse the image on the copy sheet, comprising: first and second, oppositely driven, mutually biased, pressure fixing feed rollers: a third roller laterally supporting the first and second pressure fixing rollers and driven oppositely from said second roller; a flexible, thermally conductive web for contacting the image bearing surface of said copy sheet, said web disposed about and contacting a portion of said first roller and passing through a first nip defined by the first and second rollers, said web being further disposed about and contacting the portion of the second roller between the first nip and a second nip defined by the second and third rollers in an opposite direction from the contact with said first roller, wherein the area of contact between the web and the first roller defines a concave path for the unfused copy sheet; and means for heating only said web, whereby when the unfused copy sheet is fed between said heated web and said first roller, the developed image on the copy sheet is gradually melted until said image is finally pressed and fixed on the copy sheet by passing between the first and second pressure fixing rollers.
Claim 2
Dependent Claim
221 words
A fusing apparatus for applying pressure and heat to an unfused copy sheet bearing a developed electrostatic image on at least one surface thereof in order to fuse the image on the copy sheet, comprising: first and second, oppositely driven, mutually biased, pressure fixing feed rollers: a third roller laterally supporting the first and second pressure fixing rollers and driven oppositely from said second roller; a flexible, thermally conductive web for contacting the image bearing surface of said copy sheet, said web disposed about and contacting a portion of said first roller and passing through a first nip defined by the first and second rollers, said web being further disposed about and contacting the portion of the second roller between the first nip and a second nip defined by the second and third rollers in an opposite direction from the contact with said first roller, wherein the area of contact between the web and the first roller defines a concave path for the unfused copy sheet; and means for heating only said web, whereby when the unfused copy sheet is fed between said heated web and said first roller, the developed image on the copy sheet is gradually melted until said image is finally pressed and fixed on the copy sheet by passing between the first and second pressure fixing rollers.
Claim 3
Dependent Claim
21 words
The apparatus of claim 1 wherein the second pressure fixing roller is smaller in diameter than the first pressure fixing roller.
Claim 4
Dependent Claim
24 words
The apparatus of claim 2 wherein the heating means is operatively disposed adjacent the surface of the web that contacts the unfused copy sheet.
Claim 5
Dependent Claim
26 words
The apparatus of claim 2 wherein the heating means is operatively disposed adjacent the surface of the web that does not contact the unfused copy sheet.
Claim 6
Dependent Claim
30 words
The apparatus of claim 4 wherein the heating means comprises a resistance coil situated to provide heat to two spaced locations, each of said locations being adjacent said resistance coil.
Claim 7
Dependent Claim
19 words
The apparatus of claim 4 wherein the web comprises a flexible strip of stainless steel 0.006to 0.008 inch thick.
Claim 8
Dependent Claim
22 words
The apparatus of claim 4 wherein the diameters of the first and second pressure fixing rollers are respectively 1.5 and 0.5 inches.
Claim 9
Dependent Claim
12 words
The apparatus of claim 4 wherein the web comprises an endless loop.
Claim 10
Dependent Claim
19 words
The apparatus of claim 4 wherein the web is reversibly bent 180 degrees around the second, pressure fixing roller.
Claim 11
Dependent Claim
20 words
The apparatus of claim 4 wherein the web contacts about one half the circumference of the first pressure fixing roller.
Claim 12
Independent Claim
176 words
A method of applying pressure and heat to a developed electrostatic image on the surface of a copy sheet in order to fix the image to the surface, comprising: providing first and second, oppositely driven, mutually biased, pressure fixing feed rollers, and a third roller laterally supporting the first and second pressure fixing rollers; contacting a portion of said first roller with a thermally conductive, flexible web, said web passing through a first nip defined by the first and second rollers; contacting the second roller with said web between the first nip and a second nip defined by the second and third rollers in a opposite direction from the contact with the first roller; and feeding said copy sheet between said web and said first pressure fixing roller so that the image bearing surface of the copy sheet contacts the web, whereby the developed image on the copy sheet is gradually melted until said image is finally pressed and fixed on the copy sheet by the pressing action of the first and second pressure fixing rollers.
Claim 13
Independent Claim
176 words
A method of applying pressure and heat to a developed electrostatic image on the surface of a copy sheet in order to fix the image to the surface, comprising: providing first and second, oppositely driven, mutually biased, pressure fixing feed rollers, and a third roller laterally supporting the first and second pressure fixing rollers; contacting a portion of said first roller with a thermally conductive, flexible web, said web passing through a first nip defined by the first and second rollers; contacting the second roller with said web between the first nip and a second nip defined by the second and third rollers in a opposite direction from the contact with the first roller; and feeding said copy sheet between said web and said first pressure fixing roller so that the image bearing surface of the copy sheet contacts the web, whereby the developed image on the copy sheet is gradually melted until said image is finally pressed and fixed on the copy sheet by the pressing action of the first and second pressure fixing rollers.
Claim 14
Dependent Claim
19 words
The method of claim 11, wherein the web is reversibly bent 180 degrees around the second, pressure fixing roller.
Claim 15
Dependent Claim
16 words
The method of claim 12 wherein the web is heated before it contacts the copy sheet.
Claim 16
Dependent Claim
20 words
The method of claim 13, wherein the web is heated on the surface thereof that contacts the unfused copy sheet.
Claim 17
Dependent Claim
22 words
The method of claim 13, wherein the web is heated on the surface thereof that does not contact the unfused copy sheet.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-01-06 | 1984-07-07 | 1985-01-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-01-06 | 1988-07-07 | 1989-01-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-01-06 | 1992-07-07 | 1993-01-06 | $7700.00 | Window Closed / Lapsed |