US4228469A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for time compression of facsimile transmissions
Assignee: ExxonMobil Technology and Engineering Co
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Filing: 1976-04-30
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Granted: 1980-10-14
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Expires: 1996-04-30
Abstract
Abstract In a facsimile transmission system, a transmitter comprises a read photodetector which scans a document for video content and a lead photodetector which scans the document in advance of the read photodetector. The output of the read photodetector is coupled to a modulator which generates signals for transmission to a facsimile receiver at a remote location. The output of the read photodetector and the lead photodetector are also coupled to timing circuitry which automatically initiates a fast scanning mode for the read and lead photodetectors after a predetermined time lapse without detection of a dark, information-bearing area on the document. The facsimile receiver which comprises a stylus for scanning a copy medium and a demodulator for controlling marking on the copy medium by the stylus also includes timing circuitry for automatically initiating a fast scanning mode after a predetermined lapse in time between received signals representing dark, information-bearing areas. The fast scanning modes at the transmitter and receiver are terminated in response to the first dark, information-bearing area detected by the read or lead photodetector.
Inventors
- 👤 Herbert P. Ford, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 18:18
CPC Classifications
H; H04; H04N; H04N1/00; H04N1/04; H04N1/17; H04N1/00095
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
145 words
A facsimile receiver for receiving signals representing dark-light variations in a document at a remote location, said receiver comprising: writing means for marking a copy medium; signal receiving means coupled to said writing means for generating information signals for actuating said writing means to mark said copy medium when signals representing dark regions are received; receiver scanning means for moving said document relative to said writing means in two substantially orthogonal directions at a slow scanning rate and a fast scanning rate; and receiver scanning control means coupled to said signal receiving means and responsive to the video density of said information signals for actuating said writing means for automatically initiating said fast scanning rate in both said directions when said information signals represent low video density and initiating said slow scanning rate in both said directions when said information signals represent high video density.
Claim 2
Dependent Claim
145 words
A facsimile receiver for receiving signals representing dark-light variations in a document at a remote location, said receiver comprising: writing means for marking a copy medium; signal receiving means coupled to said writing means for generating information signals for actuating said writing means to mark said copy medium when signals representing dark regions are received; receiver scanning means for moving said document relative to said writing means in two substantially orthogonal directions at a slow scanning rate and a fast scanning rate; and receiver scanning control means coupled to said signal receiving means and responsive to the video density of said information signals for actuating said writing means for automatically initiating said fast scanning rate in both said directions when said information signals represent low video density and initiating said slow scanning rate in both said directions when said information signals represent high video density.
Claim 3
Dependent Claim
141 words
A facsimile transmitter for transmitting signals representing dark and light regions on a document at the transmitter, said transmitter comprising: sensor means for sensing dark regions on the document of varying density; scanning means for moving said sensor means relative to said document in two substantially orthogonal directions at a fast scanning rate and a slow scanning rate; transmitting means coupled to said sensor means for generating information signals representing each dark region on the document sensed by the sensor means, said information signals adapted to actuate writing means at a facsimile receiver; and scanning rate control means responsive to the video density of said information signals for initiating a fast scanning rate in both directions when low video density is sensed by said sensor means and initiating a slow scanning rate in both directions when high video density is sensed.
Claim 4
Dependent Claim
141 words
A facsimile transmitter for transmitting signals representing dark and light regions on a document at the transmitter, said transmitter comprising: sensor means for sensing dark regions on the document of varying density; scanning means for moving said sensor means relative to said document in two substantially orthogonal directions at a fast scanning rate and a slow scanning rate; transmitting means coupled to said sensor means for generating information signals representing each dark region on the document sensed by the sensor means, said information signals adapted to actuate writing means at a facsimile receiver; and scanning rate control means responsive to the video density of said information signals for initiating a fast scanning rate in both directions when low video density is sensed by said sensor means and initiating a slow scanning rate in both directions when high video density is sensed.
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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) | 1983-10-14 | 1984-04-14 | 1984-10-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-10-14 | 1988-04-14 | 1988-10-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-10-14 | 1992-04-14 | 1992-10-14 | $7700.00 | Window Closed / Lapsed |