Optical scanning device and image forming apparatus
AssigneeRicoh Company, Ltd.
InventorsMakoto HIRAKAWA, Yoshinori Hayashi
Life of this patent
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Abstract
An optical scanning device that scans a scanning surface with a light beam includes a light source that emits the light beam and a pre-deflector optical system that includes at least one diffractive optical element including a diffraction surface having no power at room temperature. The diffraction surface has a multi-step shape having a plurality of zone surfaces substantially perpendicular to an optical axis and a plurality of step surfaces each adjacent to each of the zone surfaces. On a cross sectional plane of the diffraction surface including the optical axis, each of the zone surfaces and each of the step surfaces makes an obtuse angle.
Claims13
An optical scanning device that scans a scanning surface with a light beam, the optical scanning device comprising:
- a light source that emits the light beam;
- and
- a pre-deflector optical system that includes at least one diffractive optical element including a diffraction surface having no power at room temperature, wherein
- the diffraction surface has a multi-step shape having a plurality of zone surfaces substantially perpendicular to an optical axis and a plurality of step surfaces each adjacent to each of the zone surfaces, and
- on a cross sectional plane of the diffraction surface including the optical axis, each of the zone surfaces and each of the step surfaces makes an obtuse angle.
An image forming apparatus comprising:
- at least one image carrier;
- and
- at least one optical scanning device that scans the at least one image carrier with a light beam modulated according to image information, the optical scanning device including
- a light source that emits the light beam, and
- a pre-deflector optical system that includes at least one diffractive optical element including a diffraction surface having no power at room temperature, wherein
- the diffraction surface has a multi-step shape having a plurality of zone surfaces substantially perpendicular to an optical axis and a plurality of step surfaces each adjacent to each of the zone surfaces, and
- on a cross sectional plane of the diffraction surface including the optical axis, each of the zone surfaces and each of the step surfaces makes an obtuse angle.
Dependencies are inferred from the claim text.