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US 6,384,949 B1Granted
Optical scanning device, image forming apparatus and optical scanning method
AssigneeRicoh Company, Ltd.
InventorSeizo Suzuki
Life of this patent
Estimating the term…
Abstract
A coupling lens couples a light flux from a light source to form a parallel light flux, a convergent light flux or a divergent light flux. An optical deflector includes a deflective reflection surface which deflects the light flux from the coupling lens at a uniform angular velocity. A scanning image-formation optical system converges the deflected light flux received from the optical deflector on a surface to be scanned to form a beam spot. The device scans the surface to be scanned with the beam spot at a uniform velocity. A depth increasing component, increases the depth of focus determined by the entire optical system of the device, on the optical path between the light source and the deflective reflection surface.
Claims15
An optical scanning device comprising:
- a light source arranged to emit a light flux;
- an optical deflector arranged to deflect the light flux;
- a first optical system arranged to direct the light flux emitted from said light source to said optical deflector;
- and
- a second optical system arranged to direct the light flux deflected by said optical deflector onto a surface to be scanned, the deflected light flux having a depth of focus;
- wherein
- said first optical system comprises an intensity-distribution transforming unit, configured and adapted to increase the depth of focus of the light flux determined by the first and second optical systems of said device, said intensity-distribution transforming unit comprising at least one intensity-distribution transforming lens which transforms the intensity distribution of the light flux emitted from said light source into an arbitrary intensity distribution.
4 more elements
An optical scanning device comprising:
- light emitting means for emitting a light flux;
- optical deflecting means for deflecting the light flux;
- first optical means for directing the light flux emitted from said light emitting means to said optical deflecting means;
- and
- second optical means for directing the light flux deflected by said optical deflecting means onto a surface to be scanned, the deflected light flux having a depth of focus,
- wherein said first optical means comprises an intensity-distribution transforming means, configured and adapted to increase the depth of focus determined by the first and second optical means of said device, said intensity-distribution transforming means comprising at least one intensity-distribution transforming lens, for transforming the intensity distribution of the light flux emitted from said light emitting means into an arbitrary intensity distribution.
3 more elements
An image forming apparatus comprising:
- a light source arranged to emit a light flux;
- an optical deflector arranged to deflect the light flux;
- a first optical system arranged to direct the light flux emitted from said light source to said optical deflector;
- and
- a second optical system arranged to direct the light flux deflected by said optical deflector onto a surface to be scanned, the deflected light flux having a depth of focus,
- wherein said first optical system includes an intensity-distribution transforming unit, configured and adapted to increase the depth of focus determined by the first and second optical systems of said device, said intensity-distribution transforming unit comprising at least one intensity-distribution transforming lens and transforms the intensity distribution of the light flux emitted from said light source into an arbitrary intensity distribution.
3 more elements
An image forming apparatus comprising:
- light emitting means for emitting a light flux;
- optical deflecting means for deflecting the light flux;
- first optical means for directing the light flux emitted from said light emitting means to said optical deflecting means;
- and
- second optical means for directing the light flux deflected by said optical deflecting means onto a surface to be scanned, the deflected light flux having a depth of focus,
- wherein said first optical means includes an intensity-distribution transforming means, configured and adapted to increase the depth of focus determined by the first and second optical means of said device, said intensity-distribution transforming means comprising at least one intensity-distribution transforming lens, for transforming the intensity distribution of the light flux emitted from said light emitting means into an arbitrary intensity distribution.
3 more elements
An optical scanning method comprising the steps of:
- a) deflecting a light flux emitted from a light source:
- b) directing the light flux to such a place as to enable the light flux to be deflected in said step a;
- and
- c) directing the light flux deflected in said step a onto a surface to be scanned, the deflected light flux having a depth of focus,
- wherein said step b comprises the step of transforming the intensity distribution of the light flux emitted from said light source into an arbitrary intensity distribution using at least one intensity-distribution transforming lens and increasing the depth of focus determined by the first and second optical systems of said device.
2 more elements
An optical scanning device comprising:
- a light source arranged to emit a light flux;
- an optical deflector arranged to deflect the light flux;
- a first optical system arranged to direct the light flux emitted from said light source to said optical deflector;
- and
- a second optical system arranged to direct the light flux deflected by said optical deflector onto a surface to be scanned;
- wherein
- said first optical system comprises an intensity-distribution transforming unit, comprising at least one intensity-distribution transforming lens which transforms the intensity distribution of the light flux emitted from said light source into an arbitrary intensity distribution, and wherein
- the light flux onto the surface to be scanned has a peak intensity and a highest side lobe having an intensity less than 1/e2 of the peak intensity of the light flux.
5 more elements
Dependencies are inferred from the claim text.