US3833790A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Heated pressure fusing system
Assignee: Xerox Corp
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Filing: 1973-07-05
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Granted: 1974-09-03
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Expires: 1993-07-05
Abstract
Abstract An improved control for maintaining a substantially constant temperature at the contact arc or nip defined by pressure heated fusing rolls. A sensing device senses the surface temperature of each of the rools and supplies signals to a control circuit which combines the signals in a parallel resistance network. An output signal is supplied to electrical heating elements associated with at least one of the rolls to maintain a constant temperature at the nip.
Inventors
- 👤 D Quant
- 👤 E Braband
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 03:34
CPC Classifications
G; G03; G03G; G03G15/00; G03G15/20; G03G15/2003; G03G15/2014; G03G15/2039
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
170 words
In a fusing system including first and second rolls forming a nip to exert heat and pressure to fix powder images onto copy sheets, improved apparatus for maintaining a substantially constant temperature at the nip comprising first sensor means for detecting a temperature of a first roll surface to produce a first output resistance, second sensor means for detecting a temperature of a first roll surface to produce a second output resistance, first circuit means coupling said first and second output resistance to produce a combined output resistance indicative of the temperature at the nip, second circuit means coupled with said first circuit means receiving input voltage signals representative of said combined output resistance and input voltage signals representative of a reference set point indicative of the desired nip temperature to produce electrical output signals to heating means varying with the difference of the input voltage signals in response to the combined surface temperature of the rolls to maintain a substantially constant temperature at the nip under varying operating conditions.
Claim 2
Dependent Claim
170 words
In a fusing system including first and second rolls forming a nip to exert heat and pressure to fix powder images onto copy sheets, improved apparatus for maintaining a substantially constant temperature at the nip comprising first sensor means for detecting a temperature of a first roll surface to produce a first output resistance, second sensor means for detecting a temperature of a first roll surface to produce a second output resistance, first circuit means coupling said first and second output resistance to produce a combined output resistance indicative of the temperature at the nip, second circuit means coupled with said first circuit means receiving input voltage signals representative of said combined output resistance and input voltage signals representative of a reference set point indicative of the desired nip temperature to produce electrical output signals to heating means varying with the difference of the input voltage signals in response to the combined surface temperature of the rolls to maintain a substantially constant temperature at the nip under varying operating conditions.
Claim 3
Dependent Claim
20 words
A system according to claim 1 wherein said heating means is disposed interior to at least one of said rolls.
Claim 4
Dependent Claim
29 words
A system according to claim 1 wherein said second circuit means includes an operational amplifier comparing the input voltage signals to control the constant temperatures desired at the nip.
Claim 5
Dependent Claim
16 words
A system according to claim 1 wherein said first circuit means includes a parallel resistance network.
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) | 1977-09-02 | 1978-03-04 | 1978-09-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-09-02 | 1982-03-04 | 1982-09-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-09-02 | 1986-03-04 | 1986-09-03 | $7700.00 | Window Closed / Lapsed |