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US 2004/0057098 A1Published application
Light scanning apparatus and image forming apparatus
AssigneeFuji Xerox Co., Ltd.
InventorHideki Kashimura
Life of this patent
Estimating the term…
Abstract
A width in a main scanning direction of a laser beam is decreased in the outside of an effective scanning region in such a manner that the width along the main scanning direction of the laser beam is restricted by an aperture portion of an aperture member. As a result, so-called flare light is prevented from generating, and a uniformity of light quantity is improved. Namely, in a light scanning apparatus adopting an overfilled optical system, a light scanning apparatus which can prevent degradation of image quality due to flare light is obtained.
Claims22
A light scanning apparatus comprising:
- light source means for irradiating a light beam;
- a first optical system, which shapes the light beam irradiated from the light source means;
- a rotating polygon mirror, which has a plurality of reflection faces that reflect, while the rotating polygon mirror is rotated, the beam shaped by the first optical system, thereby deflection-scanning the light beam;
- a scanning optical system for focusing the light beam deflection-scanned by the rotating polygon mirror on a face being scanned, for image formation;
- and
- width reducing means for reducing a width in a main scanning direction of the light beam incident to the reflection face, the width of the light beam in the main scanning direction along a direction of the deflection-scanning having been widened larger than the width of the reflection face, by shaping with the first optical system,
- wherein the width reducing means is configured so as to reduce the width of the light beam, in a region outside an effective scanning region, in the main scanning direction.
4 more elements
A light scanning apparatus comprising:
- light source means for irradiating a light beam;
- a first optical system, which shapes the light beam irradiated from the light source means;
- a rotating polygon mirror, which has a plurality of reflection faces that reflect, while the rotating polygon mirror is rotated, the beam shaped by the first optical system, thereby deflection-scanning the light beam;
- a scanning optical system, which forcuses focusing the light beam deflection-scanned by the rotating polygon mirror on a face being scanned, for image formation;
- and
- width reducing means for reducing a width of the light beam in a main scanning direction of the light beam incident to the reflection face, the width of the light beam in the main scanning direction along a direction of the deflection-scanning having been widened larger than the width of the reflection face, by shaping with the first optical system,
- wherein, in the width reducing means, a light flux width W in the reflection face, in the direction orthogonal to an optical axis of the scanning optical system in a reflection face, satisfies the following expression;
- φ×sin(θ/2+π/n)≦W≦φ×sin(2π/n)+0.035×f
- where φ is a diameter of a circumscribed circle of the rotating polygon mirror, n is the number of faces of the rotating polygon mirror, θ is a maximum scanning half angle in scanning an effective scanning width in the face being scanned, and f is a focal distance in the main scanning direction in the entire optical system from the light source means to the first optical system, and the width in a sub-scanning direction orthogonal to the direction of the deflection-scanning is adapted to correct a light quantity distribution in the scanning direction on the face being scanned.
6 more elements
A light scanning apparatus comprising:
- light source means for irradiating a light beam;
- a first optical system, which shapes the light beam irradiated from the light source means;
- a rotating polygon mirror which has a plurality of reflection faces that reflect, while the rotating polygon mirror is rotated, the beam shaped by the first optical system, thereby deflection-scanning the light beam;
- a scanning optical system, which focuses the light beam deflection-scanned by the rotating polygon mirror on a face being scanned, for image formation;
- and
- width reducing means for reducing a width of the light beam in a main scanning direction of the light beam,
- wherein the first optical system is formed so as to increase the width of the light beam in the main scanning direction wider than the width of the reflection face, the main scanning direction being along the direction of reflection scanning, while the width reducing means is formed so as to reduce the width of the light beam in the main scanning direction, in a region outside an effective scanning region, and to correct a light quantity distribution, on the face being scanned, of the light beam such that the light quantity distribution is made uniform by changing the width in a sub-scanning direction of the width reducing means.
4 more elements
Dependencies are inferred from the claim text.