Optical system for light beam scanning
AssigneeCanon Kabushiki Kaisha
InventorKazuyuki Kondo
Life of this patent
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Abstract
A scanning optical system used for light beam scanning device is disclosed. The scanning optical system is disposed between a deflector for deflecting a light beam and a plane to be scanned. In the scanning optical system, a spherical lens having a positive power and a toric lens are arrnaged. The toric lens is positioned close to the spherical lens at the side thereof closer to the plane to be scanned. The toric lens has positive powers both in the main and sub scanning cross sectional planes. At least one of the faces of the toric lens is aspherical in the main scanning cross sectional plane.
Claims44
A scanning optical system, for use in a light beam scanning device for deflecting a light beam by deflection means thereby scanning a plane and to be positioned between said deflection means and said scanned plane, comprising:
- a spherical lens with a positive power;
- and
- a toric lens positioned close to said spherical lens at the side thereof closer to the scanned plane and having positive powers both in the main and sub scanning cross sectional planes, wherein at least one of the faces of said toric lens is aspherical in the main scanning cross sectional plane.
A scanning optical system, for use in a light beam scanning device for deflecting a light beam by deflection means thereby scanning a plane and to be positioned between said deflection means and said scanned plane, comprising:
- a first lens of a positive power composed of glass;
- and
- a second lens of a positive power composed of a plastic material, positioned close to said first lens at a side thereof closer to said scanned plane.
A scanning optical system comprising:
- a light source unit;
- a light deflector for deflecting a light beam from said light source unit;
- and
- a scanning optical system for guiding the light beam deflected by said light deflector to a surface to be scanned, wherein said scanning optical system comprises a spherical lens having a positive power and a toric lens which is disposed close to said spherical lens at the side thereof closer to the surface to be scanned and which has positive powers in main and sub scanning cross sections, and wherein at least one of the faces of said toric lens is aspherical in the main scanning cross section.
An optical system according to claim 71, wherein said spherical lens is made of a glass material and said toric lens si made of a plastic material.
A laser beam printer comprising:
- a light source unit;
- a light deflector for deflecting a light beam from said light source unit;
- a recording medium;
- and
- a scanning optical system for guiding the light beam deflected by light deflector to said recording medium, wherein said scanning optical system comprises a spherical lens having a positive power and a toric lens which is disposed close to said spherical lens at the side thereof closer to the recording medium and which has positive powers in main and sub scanning cross sections, and wherein at least one of the faces of said toric lens is aspherical in the main scanning cross section.
A scanning optical system comprising:
- a light source unit;
- a light deflector for deflecting a light beam from said light source unit;
- and
- scanning optical system for guiding the light beam deflected by said light deflector to a surface to be scanned, wherein said scanning optical system comprises a first lens which is made of a glass material and has a positive power, and a second lens which is made of a plastic material, is disposed close to said first lens at the side thereof closer to the surface to be scanned, and has a positive power.
A laser beam printer comprising:
- a light source unit;
- a light deflector for deflecting a light beam from said light source unit;
- a recording medium;
- and
- a scanning optical system for guiding the light beam deflected by said light deflector to said recording medium, wherein said scanning optical system comprises a first lens which is made of a plastic material and has a positive power, and a second lens which is disposed close to said first lens at the side thereof closer to said recording medium, is made of a plastic material and has a positive power.
Dependencies are inferred from the claim text.