US3848087A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Optical scanner control system
Assignee: RCA Corp
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Filing: 1973-10-29
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Granted: 1974-11-12
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Expires: 1993-10-29
Abstract
Abstract An apparatus to synchronize a scanning light beam, reflected from a rotationally driven polygonal mirror, with means for processing signals manifesting optical information relating to the scanning light beam of the type operating under the control of timing signals. The optical information processing apparatus may be for example, a reading, writing or facsimile apparatus. When the light beam is deflected to the beginning of an area to be scanned, an oscillator is enabled to generate a pulse train which is used as the timing signals to clock the operation of the optical information processing means. After a predetermined number of pulses, a ramp signal is initiated. When the light beam is deflected to a second location, the magnitude of the ramp signal is compared to a reference signal to generate an error signal, if any. Any error signal is applied to a servo motor control circuit which in turn applies a motor control signal to a motor driving the polygonal mirror to regulate the speed of the rotating mirror.
Inventors
- 👤 R Carrell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 17:34
CPC Classifications
H; H04; H04N; H04N1/00; H04N1/04; H04N1/047; H04N1/053; H04N3/00; H04N3/02; H04N3/08; H04N1/113; H04N1/1135; H04N2201/00; H04N2201/024; H04N2201/02406; H04N2201/02439; H04N2201/04; H04N2201/047; H04N2201/04701; H04N2201/0471; H04N2201/04732; H04N2201/04744; H04N2201/04753; H04N2201/04755; H04N2201/04758; H04N2201/04767; H04N2201/04794
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
259 words
In a scanning system wherein a polygonal mirror is rotational driven by a motor to scan a reflected light beam across a scanning area having a leading edge and including optical signal processing means for processing signals manifesting optical information relating to said scanning light beam of the type operating under the control of timing signals the improvement comprising: start detection means for producing a start signal when said light beam is deflected over said leading edge of said scanning area; stop detection means for producing a stop signal when said light beam is deflected over a location after said beginning; oscillator means responsive to said start signal and said stop signal for producing a pulse train signal starting when said start signal is received and ending when said stop signal is received; said pulse train being coupled to said optical signal processing means to form said timing signals to thereby initiate the operation of said optical signal processing means; means responsive to said pulse train signal for generating a ramp signal whose magnitude increases with time when a predetermined number of pulses in said pulse train signal have been received by said ramp generating means; means responsive to said stop signal and said ramp signal for comparing said ramp signal to a predetermined reference signal when said stop signal is received to produce an error signal; and motor servo means responsive to said error signal and coupled to said motor for changing the speed of said motor in accordance with said error signal to null said error signal.
Claim 2
Dependent Claim
259 words
In a scanning system wherein a polygonal mirror is rotational driven by a motor to scan a reflected light beam across a scanning area having a leading edge and including optical signal processing means for processing signals manifesting optical information relating to said scanning light beam of the type operating under the control of timing signals the improvement comprising: start detection means for producing a start signal when said light beam is deflected over said leading edge of said scanning area; stop detection means for producing a stop signal when said light beam is deflected over a location after said beginning; oscillator means responsive to said start signal and said stop signal for producing a pulse train signal starting when said start signal is received and ending when said stop signal is received; said pulse train being coupled to said optical signal processing means to form said timing signals to thereby initiate the operation of said optical signal processing means; means responsive to said pulse train signal for generating a ramp signal whose magnitude increases with time when a predetermined number of pulses in said pulse train signal have been received by said ramp generating means; means responsive to said stop signal and said ramp signal for comparing said ramp signal to a predetermined reference signal when said stop signal is received to produce an error signal; and motor servo means responsive to said error signal and coupled to said motor for changing the speed of said motor in accordance with said error signal to null said error signal.
Claim 3
Dependent Claim
92 words
The combination recited in claim 1 wherein said means for generating a ramp signal includes: counter means responsive to said stop signal and said pulse train signal for counting the number of pulses in said pulse train signal, said counter means generating a ramp enable signal when said counter has reached a predetermined count, said counter being reset when said stop signal is received; and ramp generating means responsive to said ramp enable signal for generating a ramp signal whose magnitude increases linearly with time when said ramp enable signal is received.
Claim 4
Dependent Claim
30 words
The combination recited in claim 2 wherein said stop means is adapted to produce a stop signal when said light beam is located at the end of said scanning area.
Claim 5
Dependent Claim
48 words
The combination recited in claim 3 wherein said light beam scans said scanning area along a scan line, said scan line containing a number of picture elements, and said predetermined count is equal to a number slightly less than the number of picture elements in a scan line.
Claim 6
Dependent Claim
117 words
The combination recited in claim 1 wherein said start detection means includes a first plate having an aperture adapted to allow the passage of said light beam therethrough when said light beam is located at the beginning of said scanning area, and first photosensitive means for receiving the light emerging from said first plate and producing said start signal therefrom; and said stop detection means includes a second plate having an aperture adapted to allow the passage of said ligHt beam therethrough when said light beam is located at a location within said scanning area and after said beginning; second photosensitive means for receiving the light emerging from said second plate and producing said stop signal therefrom.
Claim 7
Dependent Claim
74 words
The combination recited in claim 1 wherein said utilization means is a printing apparatus including memory means for storing information manifesting a font of characters; control means responsive to control signals said pulse train signal for reading out said information from said memory means in synchronism with said pulse train signal; and modulation means responsive to said information read out from said memory means for modulating said light beam in accordance with said information.
Claim 8
Dependent Claim
93 words
The combination recited in claim 1 wherein said comparator means includes: switch means having input, output and control terminals, said ramp signal being coupled to said input terminal, said stop signal being coupled to said control terminal, said switch means being adapted so that said ramp signal is conducted from said input terminal to said output terminal only upon the occurrence of stop signal; comparator means coupled to said output terminal and responsive to said predetermined reference signal for comparing said ramp signal to said predetermined reference signal to produce said error signal.
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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) | 1977-11-11 | 1978-05-13 | 1978-11-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-11-11 | 1982-05-13 | 1982-11-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-11-11 | 1986-05-13 | 1986-11-12 | $7700.00 | Window Closed / Lapsed |