US3833761A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Fluorescent lamp system for facsimile
Assignee: INT SCANATRON SYST CORP
•
Filing: 1971-07-12
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Granted: 1974-09-03
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Expires: 1991-07-12
Abstract
Abstract A fluorescent lamp for facsimile copy scanning is provided with regulated constant current for constant illumination; all solid state starter circuitry; and automatic current direction reversal once for each scanning line to prevent uneven darkening due to prolonged DC passing through the lamp in one direction.
Inventors
- 👤 D Houck
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 02:19
CPC Classifications
H; H04; H04N; H04N1/00; H04N1/40; H04N1/40056
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
99 words
In a facsimile scanning system including line by line copy scanning means and means for providing blanking pulses for each scanned line, the combination of; a fluorescent lamp for illuminating facsimile copy to be scanned; a source of constant current connected in series with said lamp and four silicon controlled rectifiers in turn connected to provide current reversing switching to said lamp; and means responsive to the line frequency blanking pulses of said facsimile system for actuating said switching means and thereby reversing the direction of current flow through said lamp for each scanning line of said facsimile copy.
Claim 2
Dependent Claim
99 words
In a facsimile scanning system including line by line copy scanning means and means for providing blanking pulses for each scanned line, the combination of; a fluorescent lamp for illuminating facsimile copy to be scanned; a source of constant current connected in series with said lamp and four silicon controlled rectifiers in turn connected to provide current reversing switching to said lamp; and means responsive to the line frequency blanking pulses of said facsimile system for actuating said switching means and thereby reversing the direction of current flow through said lamp for each scanning line of said facsimile copy.
Claim 3
Dependent Claim
79 words
In a facsimile scanning system the combination of; a fluorescent lamp including two filaments for illuminating facsimile copy to be scanned; means for supplying constant current to said lamp through said filaments; and means for starting said lamp including two back-to-back zener diodes connected in shunt wiTh said lamp for conducting said constant current through said filaments prior to firing of said lamp and a source of static high voltage in proximity to the main body of said lamp.
Claim 4
Dependent Claim
79 words
In a facsimile scanning system the combination of; a fluorescent lamp including two filaments for illuminating facsimile copy to be scanned; means for supplying constant current to said lamp through said filaments; and means for starting said lamp including two back-to-back zener diodes connected in shunt wiTh said lamp for conducting said constant current through said filaments prior to firing of said lamp and a source of static high voltage in proximity to the main body of said lamp.
Claim 5
Dependent Claim
31 words
A facsimile scanning lamp system as set forth in claim 1, and including; means for holding said constant current at a value substantially below a normal operating current prior to starting.
Claim 6
Dependent Claim
29 words
A facsimile scanning lamp system as set forth in claim 1; wherein said switching is fast enough to reverse the current through said lamp before deionization can take place.
Claim 7
Dependent Claim
31 words
A facsimile scanning lamp system as set forth in claim 2; wherein the zener voltage of said zener diodes is substantially greater than the voltage drop across said lamp while conducting.
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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) | 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 |