US4813372A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Toner image fixing apparatus
Assignee: Toshiba Corp
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Filing: 1987-05-07
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Granted: 1989-03-21
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Expires: 2007-05-07
Abstract
Abstract A thermal roller for fixing a powdered toner image onto an image receiving sheet is provided with a sub-surface resistive heat generating layer adjacent the outer surface of the roller. The thickness of the heat generating layer or the materials that constitute the layer are controlled so that the resistance per unit length of the thermal roller increases gradually in the axial direction from the center portion thereof toward and to both ends. Electrical energy passed through the heat generating layer generates a desired temperature distribution profile along the roller to provide appropriate fixing temperatures, without excessively increasing the temperature at both ends of the roller.
Inventors
- 👤 Mitutosi Kogure
- 👤 Yuka Nakamura
- 👤 Makoto Tamura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 03:11
CPC Classifications
G; G03; G03G; G03G15/00; G03G15/20; G03G15/2003; G03G15/2014; G03G15/2053; F; F16; F16C; F16C19/00; F16C19/02; F16C19/04; F16C19/06; F16C2202/00; F16C2202/20; F16C2202/24; F16C35/00; F16C35/04; F16C35/06; F16C35/07; F16C35/073
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
146 words
A toner image fixing apparatus for fixing a toner image on an image fixing material of any given width passed between fixing rollers made up of a thermal roller and a pressure roller brought into pressure contact with the thermal roller, wherein said thermal roller comprises a resistive heat generating layer formed integrally with said thermal roller near and throughout an outer surface thereof, the resistance per unit length distribution in the axial direction of said resistive heat generating layer increasing gradually from a center of said thermal roller to both ends thereof to obtain a temperature distribution on a surface of said thermal roller such that the temperature gradually decreases from the center of said thermal roller to both ends thereof, and wherein said resistive heat generating layer is formed with a roughened surface on both sides thereof to increase the heat generating area thereof.
Claim 2
Dependent Claim
146 words
A toner image fixing apparatus for fixing a toner image on an image fixing material of any given width passed between fixing rollers made up of a thermal roller and a pressure roller brought into pressure contact with the thermal roller, wherein said thermal roller comprises a resistive heat generating layer formed integrally with said thermal roller near and throughout an outer surface thereof, the resistance per unit length distribution in the axial direction of said resistive heat generating layer increasing gradually from a center of said thermal roller to both ends thereof to obtain a temperature distribution on a surface of said thermal roller such that the temperature gradually decreases from the center of said thermal roller to both ends thereof, and wherein said resistive heat generating layer is formed with a roughened surface on both sides thereof to increase the heat generating area thereof.
Claim 3
Dependent Claim
41 words
The toner image fixing apparatus as set forth in claim 1, wherein a difference in resistance per unit length between the center and the ends of said thermal roller is about 20% of a center unit resistance of said thermal roller.
Claim 4
Dependent Claim
33 words
The toner image fixing apparatus as set forth in claim 2, wherein the resistance distribution of said resistive heat generating layer is adjusted by changing the thickness of said resistive heat generating layer.
Claim 5
Dependent Claim
35 words
The toner image fixing apparatus as set forth in claim 2, wherein the resistance distribution of said resistive heat generating layer is adjusted by changing the material components that constitute said resistive heat generating layer.
Claim 6
Dependent Claim
37 words
The toner image fixing apparatus as set forth in claim 3, wherein a difference in thickness between the center and the ends of said thermal roller is about 20% of the center thickness of said thermal roller.
Claim 7
Dependent Claim
40 words
The toner image fixing apparatus as set forth in claim 5, wherein a difference in temperature between the center and the ends of said thermal roller is determined to be 20° C. or lower when said thermal roller is preheated.
Claim 8
Dependent Claim
43 words
The toner image fixing apparatus as set forth in claim 5, wherein a difference in temperature between the center and the end of said thermal roller is determined to be 10° C. or lower when said thermal roller is in a ready state.
Claim 9
Dependent Claim
39 words
The toner image fixing apparatus as set forth in claim 6, wherein temperature of said thermal roller is about 250° C. at the center thereof and about 230° C. at both ends thereof when said thermal roller is preheated.
Claim 10
Dependent Claim
42 words
The toner image fixing apparatus as set forth in claim 7, wherein temperature of said thermal roller is about 200° C. at the center thereof and about 190° C. at both ends thereof when said thermal roller is in a ready state.
Claim 11
Dependent Claim
48 words
The toner image fixing apparatus as set forth in claim 1, wherein said thermal roller is formed with a stepped portion at both ends thereof to increase a spacial insulation distance between the outermost end of said resistive heat generating layer and another element connected to electrical ground.
Claim 12
Dependent Claim
34 words
The toner image fixing apparatus as set forth in claim 1, wherein an axial length of said thermal roller is approximately equal to a maximum width of the image fixing material to be fixed.
Claim 13
Dependent Claim
125 words
A thermal toner-fixing roller for fixing a powdered toner image onto an image receiving material, comprising: a cylindrical body having a surface of revolution formed about an axis; an axially extending, electrically resistive layer on said surface having a non-uniform resistance value per unit axial length, said electrically resistive layer formed with a roughened surface on both sides thereof to increase the heat generating area thereof; and means at opposite axial ends of said resistive layer for connecting said resistive layer in an electrical circuit, whereby a current flow in said resistive layer between said axially opposite connecting means causes a temperature distribution on a surface of said body such that the temperature gradually decreases from the center of said body to both ends thereof.
Claim 14
Dependent Claim
125 words
A thermal toner-fixing roller for fixing a powdered toner image onto an image receiving material, comprising: a cylindrical body having a surface of revolution formed about an axis; an axially extending, electrically resistive layer on said surface having a non-uniform resistance value per unit axial length, said electrically resistive layer formed with a roughened surface on both sides thereof to increase the heat generating area thereof; and means at opposite axial ends of said resistive layer for connecting said resistive layer in an electrical circuit, whereby a current flow in said resistive layer between said axially opposite connecting means causes a temperature distribution on a surface of said body such that the temperature gradually decreases from the center of said body to both ends thereof.
Claim 15
Dependent Claim
25 words
The thermal toner-fixing roller of claim 12, wherein the temperature rise per unit axial length is a maximum intermediate the ends of the resistive layer.
Claim 16
Dependent Claim
33 words
The thermal toner-fixing roller of claim 13, wherein the temperature rise per unit axial length is a maximum intermediate the ends of the resistive layer and a minimum at the opposite ends thereof.
Claim 17
Dependent Claim
31 words
The thermal toner-fixing roller of claim 14, wherein said maximum value of the temperature rise per unit axial length is about 1.2 the minimum temperature rise value per unit axial length.
Claim 18
Dependent Claim
25 words
The thermal toner-fixing roller of claim 12, wherein the resistance value per unit axial length is a minimum intermediate the ends of the resistive layer.
Claim 19
Dependent Claim
33 words
The thermal toner-fixing roller of claim 16, wherein the resistance value per unit axial length is a minimum intermediate the ends of the resistive layer and a maximum at the opposite ends thereof.
Claim 20
Dependent Claim
26 words
The thermal toner-fixing roller of claim 17, wherein said maximum value of the resistance value per unit axial length is about 1.2 the minimum resistance value.
Claim 21
Dependent Claim
25 words
The thermal toner-fixing roller of claim 12, wherein the layer thickness per unit axial length is a maximum intermediate the ends of the resistive layer.
Claim 22
Dependent Claim
33 words
The thermal toner-fixing roller of claim 19, wherein the layer thickness per unit axial length is a maximum intermediate the ends of the resistive layer and a minimum at the opposite ends thereof.
Claim 23
Dependent Claim
30 words
The thermal toner-fixing roller of claim 20, wherein said maximum value of the layer thickness per unit axial length is about 1.2 the minimum layer thickness per unit axial length.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-03-20 | 1992-09-19 | 1993-03-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-03-20 | 1996-09-19 | 1997-03-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-03-20 | 2000-09-19 | 2001-03-21 | $7700.00 | Window Closed / Lapsed |