US3878358A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Digital power control
Assignee: Xerox Corp
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Filing: 1974-06-10
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Granted: 1975-04-15
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Expires: 1994-06-10
Abstract
Abstract A digital power control utilizing zero voltage switching of silicon controlled rectifiers and achieving full isolation of the load from the control circuitry. A thermistor is employed to determine the temperature of the load and a voltage step generator is utilized in conjunction with the thermistor to effect a control of the number of cycles of power to apply to the load.
Inventors
- 👤 Edward D Barton
- 👤 James M Donohue
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 12:01
CPC Classifications
H; H02; H02M; H02M7/00; H02M7/02; H02M7/04; H02M7/12; H02M7/145; H02M7/155; H02M7/1555; H02M7/1557; G; G05; G05D; G05D23/00; G05D23/19; G05D23/1906; G05D23/1913; G05D23/20; G05D23/24; G05F; G05F1/00; G05F1/10; G05F1/12; G05F1/40; G05F1/44; G05F1/45; G05F1/452
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
229 words
In a xerographic machine operable in three separate modes of warmup, standby, and print and having control apparatus for regulating the temperature of a fusing device during the modes, said control apparatus comprising, means responsive to the temperature of the fusing device for providing a temperature signal which varies as a function of the temperature, binary-counter means having an input and a plurality of outputs, with the outputs changing in response to variations in AC signals applied to the input, which are related to variations of AC energy coupled to the fusing device, generator means coupled to the outputs of the binary-counter means to generate a periodic series of electrical signals, the length of each signal being substantially equal in time to one full cycle of the AC signals, means for comparing the temperature signal and the periodic signals to generate a difference signal indicative of the difference between the temperature and periodic signAls, switching means actuatable to couple an AC energy source to the fusing device, and gating means coupled to the input of the switching means and responsive to the binary-counter means and the comparator means for applying a different combination of actuating signals to the switching means, for the different modes of the xerographic machine, to couple a number of full cycles of AC energy to the fusing device corresponding to the combination of actuating signals.
Claim 2
Dependent Claim
229 words
In a xerographic machine operable in three separate modes of warmup, standby, and print and having control apparatus for regulating the temperature of a fusing device during the modes, said control apparatus comprising, means responsive to the temperature of the fusing device for providing a temperature signal which varies as a function of the temperature, binary-counter means having an input and a plurality of outputs, with the outputs changing in response to variations in AC signals applied to the input, which are related to variations of AC energy coupled to the fusing device, generator means coupled to the outputs of the binary-counter means to generate a periodic series of electrical signals, the length of each signal being substantially equal in time to one full cycle of the AC signals, means for comparing the temperature signal and the periodic signals to generate a difference signal indicative of the difference between the temperature and periodic signAls, switching means actuatable to couple an AC energy source to the fusing device, and gating means coupled to the input of the switching means and responsive to the binary-counter means and the comparator means for applying a different combination of actuating signals to the switching means, for the different modes of the xerographic machine, to couple a number of full cycles of AC energy to the fusing device corresponding to the combination of actuating signals.
Claim 3
Dependent Claim
70 words
The apparatus of claim 1 wherein the gating means comprises a standby-mode detection means responsive to a predetermined difference signal to switch from the warmup mode to the standby mode for enabling the generation of a combination of actuating signals corresponding to the difference signal during the warmup mode and for enabling the generation of a single actuating signal during the standby mode provided said predetermined difference signal is detected.
Claim 4
Dependent Claim
65 words
The apparatus of claim 1 wherein the gating means comprises a print-mode detector means responsive to a manual control means to switch from the standby mode to the print mode for enabling the generation of a combination of actuating signals corresponding to the difference signal except that a fixed combination of actuating signals are enabled when the difference signal is less than a predetermined minimum.
Claim 5
Dependent Claim
58 words
The apparatus of claim 1 wherein the generator means comprises a plurality of gates, each having a load resistor and being sequentially enabled by the outputs of the binary-counter means, the values of the load resistors obeying a predetermined ordered relationship so as to provide a predetermined magnitude to each of the electrical signals in the periodic series.
Claim 6
Dependent Claim
13 words
The apparatus of claim 4 wherein the plurality of gates comprises seven gates.
Claim 7
Dependent Claim
22 words
The apparatus of claim 4 wherein the periodic series of electrical signals comprises eight voltage steps over a period of 132.8 milliseconds.
Claim 8
Dependent Claim
34 words
The apparatus of claim 4 wherein the load resistors increase in value from the load resistor for the gate which is first enabled to the load resistor for the gate which is last enabled.
Claim 9
Dependent Claim
34 words
The apparatus of claim 4 wherein the load resistors decrease in value from the load resistor for the gate which is first enabled to the load resistor for the gate which is last enabled.
Claim 10
Dependent Claim
43 words
The apparatus of claim 4 wherein the load resistors alternately increase and decrease in value with respect to the previous resistor, from the load resistor for the gate which is first enabled to the load resistor for the gate which is last enabled.
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) | 1978-04-14 | 1978-10-14 | 1979-04-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-04-14 | 1982-10-14 | 1983-04-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-04-14 | 1986-10-14 | 1987-04-15 | $7700.00 | Window Closed / Lapsed |