Patent US5793515A successfully refreshed from Google Patents.
US5793515A
Expired / Lapsed
US
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Optical scanning apparatus
Assignee: Fujifilm Business Innovation Corp
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Filing: 1996-10-24
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Granted: 1998-08-11
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Expires: 2016-10-24
Abstract
Abstract An optical scanning apparatus includes: a rotational polygonal mirror, on the side of which a plurality of reflecting surfaces are provided, the reflecting surfaces deflecting a beam of incident light in the primary scanning direction at a substantially equal angular velocity; a first optical system for forming a beam of light sent from the light source into an image long in the primary scanning direction in such a manner that the formed image strides over the plurality of deflecting surfaces; and an fθ lens for converging the beam of light deflected on the deflecting surface at a position close to the surface of the photoreceptor drum so that a spot of light irradiated on the photoreceptor drum can be moved at a substantially equal speed. In the optical scanning apparatus, the angles α and β satisfy the following expression: (cos((β+α)÷2))÷(cos((β-α)÷2))≧0.75 where α is the maximum deflection angle of the deflection luminous flux with respect to the optical axis of the fθ lens, and β is an angle formed between the optical axis of the first optical system projected in the subsidiary scanning direction and the optical axis.
Inventors
- 👤 Yoshihito Sekikawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 18:11
CPC Classifications
G; G02; G02B; G02B26/00; G02B26/08; G02B26/10; G02B26/12
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
264 words
An optical scanning apparatus, comprising: a light source; a rotational polygonal mirror having a plurality of reflecting surfaces parallel with a rotational axis, a luminous flux emergent from said light source being deflected on said reflecting surfaces in a primary scanning direction at a substantially constant angular velocity; a first optical system for forming a luminous flux emergent from said light source into a linear image which is long in a direction corresponding to a primary scanning direction in such a manner that said linear image strides said reflecting surfaces of said rotational polygonal mirror; and a second optical system for converting the deflected luminous flux upon a surface to be scanned so that scanning can be conducted by a spot of light at a substantially constant speed, wherein a ratio of a size of the luminous flux in a direction corresponding to the primary scanning direction, the luminous flux being emitted by said first optical system, to a size of the reflecting surface in a rotational direction is a value not less than 1.5 and not more than 4.0, an angle formed by both outermost edge portions of the deflected luminous flux is a value not less than 30° and not more than 60°, and an angle formed between a projection line obtained when an optical axis of said first optical system is projected on a plane including both outermost edge portions of the deflected luminous flux and a straight line for equally dividing an angle formed between both outermost edge portions of the deflected luminous flux into two is smaller than 90°.
Claim 2
Dependent Claim
264 words
An optical scanning apparatus, comprising: a light source; a rotational polygonal mirror having a plurality of reflecting surfaces parallel with a rotational axis, a luminous flux emergent from said light source being deflected on said reflecting surfaces in a primary scanning direction at a substantially constant angular velocity; a first optical system for forming a luminous flux emergent from said light source into a linear image which is long in a direction corresponding to a primary scanning direction in such a manner that said linear image strides said reflecting surfaces of said rotational polygonal mirror; and a second optical system for converting the deflected luminous flux upon a surface to be scanned so that scanning can be conducted by a spot of light at a substantially constant speed, wherein a ratio of a size of the luminous flux in a direction corresponding to the primary scanning direction, the luminous flux being emitted by said first optical system, to a size of the reflecting surface in a rotational direction is a value not less than 1.5 and not more than 4.0, an angle formed by both outermost edge portions of the deflected luminous flux is a value not less than 30° and not more than 60°, and an angle formed between a projection line obtained when an optical axis of said first optical system is projected on a plane including both outermost edge portions of the deflected luminous flux and a straight line for equally dividing an angle formed between both outermost edge portions of the deflected luminous flux into two is smaller than 90°.
Claim 3
Dependent Claim
132 words
The optical scanning apparatus according to claim 1, said first optical system including: a collimator lens arranged in an emergent direction of said light source; a subsidiary scanning direction adjusting lens arranged on the emergent side of said collimator lens, said subsidiary scanning direction adjusting lens having a lens power in a direction corresponding to the subsidiary scanning direction of the luminous flux emergent from said collimator lens; and a primary scanning direction adjusting lens arranged on the emergent side of said subsidiary scanning direction adjusting lens, said primary scanning direction adjusting lens having a lens power in a direction corresponding to the primary scanning direction of the luminous flux emergent from said subsidiary scanning direction adjusting lens, wherein said light source is arranged inside a focal position of said collimator lens.
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) | 2001-08-10 | 2002-02-09 | 2002-08-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-08-10 | 2006-02-09 | 2006-08-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-08-10 | 2010-02-09 | 2010-08-11 | $7700.00 | Window Closed / Lapsed |