EP0050010A2
Expired / Lapsed
EP
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Method of and system for laser beam recording
Assignee: Fujifilm Holdings Corp
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Filing: 1981-10-08
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Granted: —
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Expires: 2001-10-08
Abstract
Abstract A recording laser beam (1a) is modulated by modulator (3) in accordance with an image signal from information source (17). The modulated beam is combined with a reference laser beam (2a) and scanned by galvanometer mirror (6). The beams are separated by beam-splitter (8) and the modulated beam (L1) scans recording material (9) in the main scanning direction (A). Reference beam (L2) traverses linear encoder (10) and the light passing therethrough is detected by photodetector (12). A pulse (P2) of constant time is generated by one-shot multivibrator (15) after each position reference pulse from photodetector (12). Pulses (P2) close analog switch (16) whereby between each position reference pulse the modulated beam is supplied for the constant time and is null for the rest of the time interval between adjacent position reference pulses. As a result, unit area of the recording material is exposed to the recording laser beam for a predetermined constant time interval regardless of fluctuations in the scanning speed of the recording laser beam.
Inventors
- 👤 Yuji Ohara
- 👤 Kazuo Horikawa
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-08 21:32
CPC Classifications
H; H04; H04N; H04N1/00; H04N1/40; H04N1/401; H04N1/4015
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
88 words
A laser beam recording method in which a laser beam is modulated by a light modulator in accordance with an image signal and caused to two-dimensionally scan a photosensitive recording material capable of recording half tone images characterized by generating a position reference pulse each time the laser beam moves across the photosensitive recording material by a predetermined constant distance in the main scanning direction, and making the intensity of the laser beam essentially null for all but a predetermined constant time interval between adjacent position reference signals.
Claim 2
Dependent Claim
88 words
A laser beam recording method in which a laser beam is modulated by a light modulator in accordance with an image signal and caused to two-dimensionally scan a photosensitive recording material capable of recording half tone images characterized by generating a position reference pulse each time the laser beam moves across the photosensitive recording material by a predetermined constant distance in the main scanning direction, and making the intensity of the laser beam essentially null for all but a predetermined constant time interval between adjacent position reference signals.
Claim 3
Dependent Claim
47 words
A laser beam recording method as defined in Claim 1 in which said image signal is fed to the light modulator for said constant time interval between adjacent position reference pulses and is not fed to the light modulator for the rest of the time interval therebetween.
Claim 4
Dependent Claim
123 words
A laser beam recording system comprising an image signal generating means, a laser source, a light modulator for modulating a laser beam emitted from the laser source in accordance with the image signal generated by the image signal generating means,.a photosensitive recording material capable of recording half tone images, means for causing the modulated laser beam to two-dimensionally scan the photosensitive recording material in main and sub scanning directions, means for generating a position reference pulse each time the modulated laser beam moves across the photosensitive recording material by a predetermined constant distance in the main scanning direction, and means for preventing transfer of the image signal to the light modulator for all but a predetermined constant time interval between adjacent position reference'pulses.
Claim 5
Dependent Claim
123 words
A laser beam recording system comprising an image signal generating means, a laser source, a light modulator for modulating a laser beam emitted from the laser source in accordance with the image signal generated by the image signal generating means,.a photosensitive recording material capable of recording half tone images, means for causing the modulated laser beam to two-dimensionally scan the photosensitive recording material in main and sub scanning directions, means for generating a position reference pulse each time the modulated laser beam moves across the photosensitive recording material by a predetermined constant distance in the main scanning direction, and means for preventing transfer of the image signal to the light modulator for all but a predetermined constant time interval between adjacent position reference'pulses.
Claim 6
Dependent Claim
64 words
A system as defined in Claim 3 in which said means for generating the position reference pulses comprises means for extracting a part of the laser beam after the laser beam is deflected in the main scanning direction, causing the • extracted part of the laser beam to scan a linear encoder having regularly-spaced transmittance variations, and detecting light passing through the linear encoder.
Claim 7
Dependent Claim
67 words
A system as defined in Claim 3 or 4 in which said means for preventing transfer of the image signal comprises an analog switch connected between said image signal generating means and said light modulator, and means connected between the means for generating the position reference pulses and the analog switch for closing the analog switch for said predetermined constant time interval between adjacent position reference pulses.
Claim 8
Dependent Claim
102 words
A system as defined in Claim 3 in which said means for generating position reference pulses comprises a reference laser beam source for emitting a reference laser beam which is synthesized with said laser beam to be deflected by a deflecting means together therewith in the main scanning direction, light separating means for extracting the reference laser beam from the synthesized laser beam after the synthesized laser beam is deflected in the main scanning direction, photodetecting means for detecting the extracted reference laser beam and a linear encoder having regularly-spaced transmittance variations disposed between the light separating means and the photodetecting means.
References Cited (Backward Citations)
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