Patent US4959664A successfully refreshed from Google Patents.
US4959664A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Laser scanner with beam transmissivity control
Assignee: Minolta Co Ltd
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Filing: 1988-08-26
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Granted: 1990-09-25
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Expires: 2008-08-26
Abstract
Abstract A light amount correcting interference membrane having almost constant thickness and characteristic for increasing transmissivity corresponding to an increase of incidence angle of a laser beam is provided on a scanning light path extending from a rotary optical deflector to a recording medium in a scanning optical system. The laser beam deflected by the rotary optical deflector for scanning the recording medium is transmitted through the light amount correcting interference membrane wherein the scanning velocity of the laser beam reaching the peripheral portion of the recording medium is faster than that of the laser beam reaching the central portion, and an incidence angle becomes large and transmissivity becomes high.
Inventors
- 👤 Toshio Naiki
- 👤 Muneo Kuroda
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 22:44
CPC Classifications
G; G06; G06K; G06K15/00; G06K15/02; G06K15/12; G06K15/1204; G06K15/1219
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
100 words
A scanning optical system for use in a laser beam printer, comprising: a laser beam generating means; a rotary deflection means for deflecting the laser beam emitted from the laser beam generating means to a recording medium so as to cause the laser beam to scan the recording medium according to rotation thereof; and an optical member provided on a scanning light path extending from the rotary deflection means to the recording medium and having an interference membrane almost in a constant thickness with a characteristic of increasing transmissivity corresponding to an increase of incidence angle of a laser beam.
Claim 2
Dependent Claim
100 words
A scanning optical system for use in a laser beam printer, comprising: a laser beam generating means; a rotary deflection means for deflecting the laser beam emitted from the laser beam generating means to a recording medium so as to cause the laser beam to scan the recording medium according to rotation thereof; and an optical member provided on a scanning light path extending from the rotary deflection means to the recording medium and having an interference membrane almost in a constant thickness with a characteristic of increasing transmissivity corresponding to an increase of incidence angle of a laser beam.
Claim 3
Dependent Claim
26 words
A scanning optical system as defined in claim 1 wherein the optical member includes a light transmissible base plate on which the interference membrane is provided.
Claim 4
Dependent Claim
24 words
A scanning optical system as defined in claim 2 wherein the laser beam enters the optical member from the side of the interference membrane.
Claim 5
Dependent Claim
25 words
A scanning optical system as defined in claim 3 wherein a refractive index of the interference membrane is larger than that of the base plate.
Claim 6
Dependent Claim
18 words
A scanning optical system as defined in claim 1 wherein the rotary deflection means is a polygon mirror.
Claim 7
Dependent Claim
47 words
A scanning optical system as defined in claim 1 further comprising: a modulation frequency correcting means for correcting modulation frequency of the laser beam to become higher corresponding to an increase of scanning velocity to alter outputting time of the laser beam and outputting interval time therebetween.
Claim 8
Dependent Claim
133 words
A scanning optical system for use in a laser printer, comprising: a laser beam generating means; a polygon mirror for deflecting the laser beam emitted from the laser beam generating means to a recording medium so as to cause the laser beam to scan the recording medium according to rotation thereof; an optical member provided on a scanning light path extending from a polygon mirror to a recording medium and having an interference membrane almost in a constant thickness with a characteristic of increasing transmissivity corresponding to an increase of incidence angle of a laser beam; and a modulation frequency correcting means for correcting modulation frequency of the laser beam to become higher corresponding to an increase of scanning velocity to alter outputting time of the laser beam and outputting interval time therebetween.
Claim 9
Dependent Claim
133 words
A scanning optical system for use in a laser printer, comprising: a laser beam generating means; a polygon mirror for deflecting the laser beam emitted from the laser beam generating means to a recording medium so as to cause the laser beam to scan the recording medium according to rotation thereof; an optical member provided on a scanning light path extending from a polygon mirror to a recording medium and having an interference membrane almost in a constant thickness with a characteristic of increasing transmissivity corresponding to an increase of incidence angle of a laser beam; and a modulation frequency correcting means for correcting modulation frequency of the laser beam to become higher corresponding to an increase of scanning velocity to alter outputting time of the laser beam and outputting interval time therebetween.
Claim 10
Dependent Claim
26 words
A scanning optical system as defined in claim 7 wherein the optical member includes a light transmissible base plate on which the interference membrane is provided.
Claim 11
Dependent Claim
24 words
A scanning optical system as defined in claim 8 wherein the laser beam enters the optical member from the side of the interference membrane.
Claim 12
Dependent Claim
25 words
A scanning optical system as defined in claim 9 wherein a refractive index of the interference membrane is larger than that of the base plate.
Claim 13
Dependent Claim
132 words
A laser beam printer, comprising: a laser beam generating means; a recording medium moving for subscanning; a polygon mirror disposed between the laser beam generating means and a recording medium which performs mainscanning on the surface of the recording medium by deflecting the laser beam emitted from the laser beam generating means to the recording medium; an optical member provided between the polygon mirror and the recording medium and having an interference membrane almost in a constant thickness with a characteristic of increasing transmissivity corresponding to an increase of incidence angle of a laser beam; and a modulation frequency correcting means for correcting modulation frequency of the laser beam to become higher corresponding to an increase of scanning velocity to alter outputting time of the laser beam and outputting interval time therebetween.
Claim 14
Dependent Claim
132 words
A laser beam printer, comprising: a laser beam generating means; a recording medium moving for subscanning; a polygon mirror disposed between the laser beam generating means and a recording medium which performs mainscanning on the surface of the recording medium by deflecting the laser beam emitted from the laser beam generating means to the recording medium; an optical member provided between the polygon mirror and the recording medium and having an interference membrane almost in a constant thickness with a characteristic of increasing transmissivity corresponding to an increase of incidence angle of a laser beam; and a modulation frequency correcting means for correcting modulation frequency of the laser beam to become higher corresponding to an increase of scanning velocity to alter outputting time of the laser beam and outputting interval time therebetween.
Claim 15
Dependent Claim
26 words
A laser beam printer as defined in claim 11 wherein the optical member includes a light transmissible base plate on which an interference membrane is provided.
Claim 16
Dependent Claim
24 words
A laser beam printer as defined in claim 12 wherein a laser beam enters the optical member from the side of the interference membrane.
Claim 17
Dependent Claim
25 words
A laser beam printer as defined in claim 13 wherein a refractive index of the interference membrane is larger than that of the base plate.
Claim 18
Dependent Claim
103 words
A scanning optical system for use in a laser beam printer, comprising: a laser beam generating means; a deflection means for deflecting the laser beam emitted from the laser beam generating means to a recording medium so as to cause the laser beam to scan across the recording medium; and an optical member provided on a scanning light path extending from the deflection means to the recording medium, the optical member including a light transmissible base plate and an interference filter having a substantially constant thickness with a characteristic of increasing transmissivity corresponding to an increase of incidence angle of a laser beam.
Claim 19
Dependent Claim
103 words
A scanning optical system for use in a laser beam printer, comprising: a laser beam generating means; a deflection means for deflecting the laser beam emitted from the laser beam generating means to a recording medium so as to cause the laser beam to scan across the recording medium; and an optical member provided on a scanning light path extending from the deflection means to the recording medium, the optical member including a light transmissible base plate and an interference filter having a substantially constant thickness with a characteristic of increasing transmissivity corresponding to an increase of incidence angle of a laser beam.
Claim 20
Dependent Claim
25 words
A scanning optical system as defined in claim 15, wherein a refractive index of the interference filter is larger than that of the base plate.
Claim 21
Dependent Claim
17 words
A scanning optical system as defined in claim 15, wherein the deflection means is a polygon mirror.
Claim 22
Dependent Claim
116 words
In a laser beam scanning system having a laser beam generator and a rotary deflector which deflects the laser beam generated from the laser beam generator to a beam receiving plane so as to cause the laser beam to scan the beam receiving plane according to rotation thereof, the improvement comprising: an interference filter provided between the rotary deflector and the beam receiving plane, said interference filter having a substantially constant thickness with a characteristic of increasing transmissivity corresponding to an increase of incidence angle of the laser beam in order to obtain a substantially constant light amount on the beam receiving plane despite a varying incidence angle of the laser beam during the scanning operation.
Claim 23
Dependent Claim
116 words
In a laser beam scanning system having a laser beam generator and a rotary deflector which deflects the laser beam generated from the laser beam generator to a beam receiving plane so as to cause the laser beam to scan the beam receiving plane according to rotation thereof, the improvement comprising: an interference filter provided between the rotary deflector and the beam receiving plane, said interference filter having a substantially constant thickness with a characteristic of increasing transmissivity corresponding to an increase of incidence angle of the laser beam in order to obtain a substantially constant light amount on the beam receiving plane despite a varying incidence angle of the laser beam during the scanning operation.
Claim 24
Dependent Claim
154 words
In an improved scanning optical system for use in a laser beam printer having a laser beam generating means for providing a laser beam that can be modulated with printing information and means for scanning the laser beam across a recording surface from a central on axis position to respective peripheral portions of the recording surface with a resulting variance in angle of the laser beam from the central on axis position, the improvement comprising; an optically transmissive member mounted in a scanning path of the laser beam before the recording surface and having a coating layer, an index of refraction and optical thickness of predetermined values, extending across the scanning path to lessen the angle of transmission of the incident laser beam relative to any corresponding increase in angle of incident on the coating layer to insure a relatively even transmission of the laser beam across the scan path to the recording member.
Claim 25
Dependent Claim
154 words
In an improved scanning optical system for use in a laser beam printer having a laser beam generating means for providing a laser beam that can be modulated with printing information and means for scanning the laser beam across a recording surface from a central on axis position to respective peripheral portions of the recording surface with a resulting variance in angle of the laser beam from the central on axis position, the improvement comprising; an optically transmissive member mounted in a scanning path of the laser beam before the recording surface and having a coating layer, an index of refraction and optical thickness of predetermined values, extending across the scanning path to lessen the angle of transmission of the incident laser beam relative to any corresponding increase in angle of incident on the coating layer to insure a relatively even transmission of the laser beam across the scan path to the recording member.
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) | 1993-09-24 | 1994-03-26 | 1994-09-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-09-24 | 1998-03-26 | 1998-09-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-09-24 | 2002-03-26 | 2002-09-25 | $7700.00 | Window Closed / Lapsed |