US5212501A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Image recording apparatus with a laser optical unit
Assignee: Minolta Co Ltd
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Filing: 1992-04-29
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Granted: 1993-05-18
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Expires: 2012-04-29
Abstract
Abstract An image recording apparatus wherein a laser diode which is disposed on a focal point of a micro Fresnel lens emits a laser beam and the laser beam is collimated by the Fresnel lens and scanned on a photosensitive drum by a polygonal mirror and an fθ optical system. A change in temperature of the laser diode does not result in such serious defocus as to cause practical problems.
Inventors
- 👤 Hiromu Nakamura
- 👤 Akiyoshi Hamada
- 👤 Satoru Ono
- 👤 Masanori Murakami
- 👤 Toshio Naiki
- 👤 Kunihiko Omura
- 👤 Masahito Niikawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 19:50
CPC Classifications
G; G06; G06K; G06K15/00; G06K15/02; G06K15/12; G06K15/1204; G06K15/1219; G02; G02B; G02B26/00; G02B26/08; G02B26/10; G02B26/12; G02B26/124; G02B5/00; G02B5/18; G02B5/1876; G06K15/1209; G06K15/1214
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
172 words
An image recording apparatus comprising: a laser diode for emitting a laser beam in accordance with image data; a convergent member having a diffraction effect for collimating the laser beam, the convergent member being disposed in front of the laser diode; and optical scanning means for scanning the laser beam which passed through the convergent member on an image surface; wherein the image recording apparatus meets a condition expressed by an expression ##EQU17## in which expression, Δλ denotes a variation in wavelength of the laser beam from a designed wavelength λ with a rise in temperature of the laser diode from a standard temperature; f co denotes a focal length of the convergent member when the laser beam has the wavelength λ; D 0 denotes a diameter of a beam spot on the image surface when the laser beam has the wavelength λ; D 1 denotes a tolerable limit of the diameter of the beam spot; and f H denotes a focal length of the optical scanning means in a main-scanning direction.
Claim 2
Dependent Claim
172 words
An image recording apparatus comprising: a laser diode for emitting a laser beam in accordance with image data; a convergent member having a diffraction effect for collimating the laser beam, the convergent member being disposed in front of the laser diode; and optical scanning means for scanning the laser beam which passed through the convergent member on an image surface; wherein the image recording apparatus meets a condition expressed by an expression ##EQU17## in which expression, Δλ denotes a variation in wavelength of the laser beam from a designed wavelength λ with a rise in temperature of the laser diode from a standard temperature; f co denotes a focal length of the convergent member when the laser beam has the wavelength λ; D 0 denotes a diameter of a beam spot on the image surface when the laser beam has the wavelength λ; D 1 denotes a tolerable limit of the diameter of the beam spot; and f H denotes a focal length of the optical scanning means in a main-scanning direction.
Claim 3
Dependent Claim
22 words
An image recording apparatus as claimed in claim 1, wherein the laser diode and the convergent member are assembled into a unit.
Claim 4
Dependent Claim
32 words
An image recording apparatus as claimed in claim 1, wherein the convergent member is a micro Fresnel lens which has a pattern of concentric circles pitched by microns on a sawtooth surface.
Claim 5
Dependent Claim
17 words
An image recording apparatus as claimed in claim 1, wherein the convergent member is made of resin.
Claim 6
Dependent Claim
23 words
An image recording apparatus as claimed in claim 1, wherein the optical scanning means comprises a polygonal mirror and an fθ optical system.
Claim 7
Dependent Claim
190 words
An image recording apparatus comprising: a laser diode for emitting a laser beam in accordance with image data; a convergent member having a diffraction effect for converging the laser beam into a convergent pencil of rays, the convergent member being disposed in front of the laser diode; and optical scanning means for scanning the laser beam which passed through the convergent member on an image surface; wherein the image recording apparatus meets a condition expressed by an expression ##EQU18## in which expression, Δλ denotes a variation in wavelength of the laser beam from a designed wavelength λ with a rise in temperature of the laser diode from a standard temperature; f co denotes a focal length of the convergent member when the laser beam has the wavelength λ; D 0 denotes a diameter of a beam spot on the image surface when the laser beam has the wavelength λ; D 1 denotes a tolerable limit of the diameter of the beam spot; b 1 denotes a distance between the convergent member and its image point; and b 2 denotes a distance between the optical scanning means and the image surface.
Claim 8
Dependent Claim
190 words
An image recording apparatus comprising: a laser diode for emitting a laser beam in accordance with image data; a convergent member having a diffraction effect for converging the laser beam into a convergent pencil of rays, the convergent member being disposed in front of the laser diode; and optical scanning means for scanning the laser beam which passed through the convergent member on an image surface; wherein the image recording apparatus meets a condition expressed by an expression ##EQU18## in which expression, Δλ denotes a variation in wavelength of the laser beam from a designed wavelength λ with a rise in temperature of the laser diode from a standard temperature; f co denotes a focal length of the convergent member when the laser beam has the wavelength λ; D 0 denotes a diameter of a beam spot on the image surface when the laser beam has the wavelength λ; D 1 denotes a tolerable limit of the diameter of the beam spot; b 1 denotes a distance between the convergent member and its image point; and b 2 denotes a distance between the optical scanning means and the image surface.
Claim 9
Dependent Claim
22 words
An image recording apparatus as claimed in claim 6, wherein the laser diode and the convergent member are assembled into a unit.
Claim 10
Dependent Claim
32 words
An image recording apparatus as claimed in claim 6, wherein the convergent member is a micro Fresnel lens which has a pattern of concentric circles pitched by microns on a sawtooth surface.
Claim 11
Dependent Claim
17 words
An image recording apparatus as claimed in claim 6, wherein the convergent member is made of resin.
Claim 12
Dependent Claim
23 words
An image recording apparatus as claimed in claim 6, wherein the optical scanning means comprises a polygonal mirror and an fθ optical system.
Claim 13
Dependent Claim
168 words
An image recording apparatus comprising: a laser diode for emitting a laser beam in accordance with image data; a convergent member having a diffraction effect for converging the laser beam, the convergent member being disposed in front of the laser diode; optical scanning means for scanning the laser beam which passed through the convergent member on an image surface; current supply means for supplying the laser diode with a current, the current being switched between a first level in accordance with a first state of image data and a second level in accordance with a second state of image data; and current control means for adjusting the first level of the current so that the laser diode keeps its output at a specified level; wherein the first level and the second level of the current are determined such that the laser beam varies its wavelength only within a specified range while the laser diode is supplied with the current switched between the first level and the second level.
Claim 14
Dependent Claim
168 words
An image recording apparatus comprising: a laser diode for emitting a laser beam in accordance with image data; a convergent member having a diffraction effect for converging the laser beam, the convergent member being disposed in front of the laser diode; optical scanning means for scanning the laser beam which passed through the convergent member on an image surface; current supply means for supplying the laser diode with a current, the current being switched between a first level in accordance with a first state of image data and a second level in accordance with a second state of image data; and current control means for adjusting the first level of the current so that the laser diode keeps its output at a specified level; wherein the first level and the second level of the current are determined such that the laser beam varies its wavelength only within a specified range while the laser diode is supplied with the current switched between the first level and the second level.
Claim 15
Dependent Claim
37 words
An image recording apparatus as claimed in claim 11, wherein the current control means controls the current supply means so that the first level and the second level have a difference not more than a specified amount.
Claim 16
Dependent Claim
22 words
An image recording apparatus as claimed in claim 11, wherein the laser diode and the convergent member are assembled into a unit.
Claim 17
Dependent Claim
32 words
An image recording apparatus as claimed in claim 11, wherein the convergent member is a micro Fresnel lens which has a pattern of concentric circles pitched by microns on a sawtooth surface.
Claim 18
Dependent Claim
17 words
An image recording apparatus as claimed in claim 11, wherein the convergent member is made of resin.
Claim 19
Dependent Claim
145 words
An image recording apparatus comprising: a laser diode for emitting a laser beam in accordance with image data; a convergent member having a diffraction effect for converging the laser beam, the convergent member being disposed in front of the laser diode; optical scanning means for scanning the laser beam which passed through the convergent member on an image surface; current supply means for supplying the laser diode with a current, the current being switched between a first level in accordance with a first state of image data and a second level in accordance with a second state of image data; and current control means for adjusting the first level so that the laser diode keeps its output at a specified level and for adjusting the second level so that the first level and the second level has a difference not more than a specified amount.
Claim 20
Dependent Claim
145 words
An image recording apparatus comprising: a laser diode for emitting a laser beam in accordance with image data; a convergent member having a diffraction effect for converging the laser beam, the convergent member being disposed in front of the laser diode; optical scanning means for scanning the laser beam which passed through the convergent member on an image surface; current supply means for supplying the laser diode with a current, the current being switched between a first level in accordance with a first state of image data and a second level in accordance with a second state of image data; and current control means for adjusting the first level so that the laser diode keeps its output at a specified level and for adjusting the second level so that the first level and the second level has a difference not more than a specified amount.
Claim 21
Dependent Claim
22 words
An image recording apparatus as claimed in claim 16, wherein the laser diode and the convergent member are assembled into a unit.
Claim 22
Dependent Claim
32 words
An image recording apparatus as claimed in claim 16, wherein the convergent member is a micro Fresnel lens which has a pattern of concentric circles pitched by microns on a sawtooth surface.
Claim 23
Dependent Claim
17 words
An image recording apparatus as claimed in claim 16, wherein the convergent member is made of resin.
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) | 1996-05-17 | 1996-11-16 | 1997-05-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-05-17 | 2000-11-16 | 2001-05-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-05-17 | 2004-11-16 | 2005-05-18 | $7700.00 | Window Closed / Lapsed |