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US 6,639,704 B2Granted
Scanning optical apparatus, and image forming apparatus using the same
AssigneeCanon Kabushiki Kaisha
InventorKazumi Kimura
Life of this patent
Estimating the term…
Abstract
A scanning optical apparatus which includes incident optical system for causing at least one light beam emitted by light source onto a deflector, and image forming optical system, having at least one diffraction surface, for imaging the at least one light beam reflected and deflected by the deflector on a surface to be scanned. The apparatus further includes limiting member, inserted in the optical path between the diffraction surface of the image forming optical system and the surface to be scanned, for limiting unnecessary diffraction light of another order with respect to diffraction light of an order used to form a spot on the surface to be scanned from among the diffraction light diffracted by the diffraction surface.
Claims16
A scanning optical apparatus comprising:
- incident optical means for causing at least one light beam emitted by light source means to be incident on deflection means;
- image forming means, having at least one diffraction surface, for forming an image using the at least one light beam reflected and deflected by the deflection means on a surface to be scanned;
- and
- limiting means, inserted in an optical path between the at least one diffraction surface of said image forming means and the surface to be scanned, for limiting unnecessary diffraction light of an order different with respect to an order of diffraction light used to form a spot on the surface to be scanned from the diffraction light diffracted by the at least one diffraction surface of said image forming means,
- wherein a condition:
- 4≦m/n≦7
- is satisfied, where n represents the order of the diffraction light used and m represents the order of the unnecessary diffraction light.
4 more elements
A scanning optical apparatus comprising:
- incident optical means for causing at least one light beam emitted by light source means to be incident on deflection means;
- image forming means, having at least one diffraction surface, for forming an image using the at least one light beam reflected and deflected by the deflection means on a surface to be scanned;
- and
- limiting means, inserted in an optical path between the at least one diffraction surface of said image forming means and the surface to be scanned, for limiting unnecessary diffraction light of an order different with respect to an order of diffraction light used to form a spot on the surface to be scanned from the diffraction light diffracted by the at least one diffraction surface of said image forming means,
- wherein said limiting means is formed by an entrance window and/or an exit window formed on a casing which holds at least one of a plurality of components that build said scanning optical device.
2 more elements
A scanning optical apparatus comprising:
- incident optical means for causing at least one light beam emitted by light source means to be incident on deflection means;
- image forming means, having at least one diffraction surface, for forming an image using the at least one light beam reflected and deflected by the deflection means on a surface to be scanned;
- and
- limiting means, inserted in an optical path between the at least one diffraction surface of said image forming means and the surface to be scanned, for limiting unnecessary diffraction light of an order different with respect to an order of diffraction light used to form a spot on the surface to be scanned from the diffraction light diffracted by the at least one diffraction surface of said image forming means,
- wherein a scan width of the unnecessary diffraction light satisfies:
- Lm/Lo<0.8
- where Lm represents the scan width of the unnecessary diffraction light and Lo represents an effective scan width.
4 more elements
A scanning optical apparatus comprising:
- incident optical means for causing at least one light beam emitted by light source means to be incident on deflection means;
- image forming means, having at least one diffraction surface, for forming an image using the at least one light beam reflected and deflected by the deflection means on a surface to be scanned;
- and
- limiting means, inserted in an optical path between the at least one diffraction surface of said image forming means and the surface to be scanned, for limiting unnecessary diffraction light of an order different with respect to an order of diffraction light used to form a spot on the surface to be scanned from the diffraction light diffracted by the at least one diffraction surface of said image forming means,
- wherein a condition:
- φo<S<φm
- is satisfied, where S represents a width of an aperture of said limiting means in a sub-scanning direction, φo represents a light beam size, with respect to the sub-scanning direction of the light beam that is to form a primary beam spot, at the position of said limiting means, and φm represents a size of stray light of reflected sixth-order diffraction light with respect to the sub-scanning direction.
4 more elements
A scanning optical apparatus comprising:
- incident optical means for causing at least one light beam emitted by light source means to be incident on deflection means;
- image forming means, having at least one diffraction surface, for forming an image using the at least one light beam reflected and deflected by the deflection means on a surface to be scanned;
- and
- limiting means, inserted in an optical path between the at least one diffraction surface of said image forming means and the surface to be scanned, for limiting unnecessary diffraction light of an order different with respect to an order of diffraction light used to form a spot on the surface to be scanned from the diffraction light diffracted by the at least one diffraction surface of said image forming means,
- wherein a condition:
- {square root over ((S/φm))}<Lm/Lo
- is satisfied, where S represents a width of an aperture of said limiting means in the sub-scanning direction, φm represents a size of stray light of reflected sixth-order diffraction light with respect to the sub-scanning direction, Lm represents a scan width of the unnecessary diffraction light, and Lo represents an effective scan width.
4 more elements
A scanning optical apparatus comprising:
- incident optical means for causing at least one light beam emitted by light source means to be incident on deflection means;
- image forming means, having at least one diffraction surface, for forming an image using the at least one light beam reflected and deflected by the deflection means on a surface to be scanned;
- and
- limiting means, inserted in an optical path between the at least one diffraction surface of said image forming means and the surface to be scanned, for limiting unnecessary diffraction light of an order different with respect to an order of diffraction light used to form a spot on the surface to be scanned from the diffraction light diffracted by the at least one diffraction surface of said image forming means.
1 more element
Dependencies are inferred from the claim text.