US 2003/0151826 A1Published application

Optical recording apparatus

AssigneeHitachi Printing Solutions, Ltd.

InventorsYasuyuki Shibayama, Keiji Kataoka

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Abstract

An optical recording apparatus includes an optical system, a photosensitive drum and a rotational mechanism. Multibeam laser light is focused through the optical system to form an image as a column of image-forming beam spots on the photosensitive drum. The column of image-forming beam spots is arranged obliquely on the photosensitive drum and scanned to perform optical recording. The optical system includes a resolution converting lens system which is detachably attached into the optical system. The rotating mechanism adjusts rotation of the resolution converting lens system around an optical axis thereof. The resolution converting lens system is rotated by the rotating mechanism to change of resolution of the recording image. The resolution converting lens system is attached into and detached from the optical system to change of resolution of the recording image.

Claims9

Dependent claims

An optical recording apparatus comprising:

an optical system;
and
a photosensitive drum on which multibeam laser light is focused through the optical system to form an image as a column of image-forming beam spots, the column of image-forming beam spots being arranged obliquely on the photosensitive drum and scanned to perform optical recording;
wherein:
the optical system includes at least one beam expander and a resolution converting lens system;
the beam expander comprises a front lens and a rear lens;
the resolution converting lens system is detachably attached into the optical system;
the resolution converting lens system includes a spherical lens and first and second cylindrical lenses having lens power only in a subsidiary scanning direction;
the spherical lens includes an input side principal surface and an output side principal surface;
and
the spherical lens is disposed in a position such that a satisfies expressions (A) and (B)
a2+(HHS3+δ)·a−(HHS3+δ)·fS3=0 (A) δ=(t1+t2)−(n1·t2+n2·t1)/(n1·n2) (B)
in which a is a distance from a front focal point of the rear lens to the input side principal surface, fS3 is a focal length of the spherical lens, HHS3 is a distance between the input side principal surface and the output side principal surface, n1 is a refractive index of the first cylindrical lens, n2 is a refractive index of the second cylindrical lens, t1 is a thickness of a center of said first cylindrical lens, and t2 is a thickness of a center of the second cylindrical lens.

10 more elements

An optical recording apparatus comprising:

an optical system;
a photosensitive drum on which multibeam laser light is focused through the optical system to form an image as a column of image-forming beam spots, the column of image-forming beam spots being arranged obliquely on the photosensitive drum and scanned to perform optical recording;
and
a controller;
wherein
the optical system includes at least one beam expander and a resolution converting lens system;
the beam expander comprises a front lens and a rear lens;
the resolution converting lens system is detachably attached into the optical system;
the controller controls the resolution converting lens system to attach into and detach from the optical system;
the resolution converting lens system includes a spherical lens and two cylindrical lenses both having lens power only in a subsidiary scanning direction;
and
the resolution converting lens system is controlled by the controller to satisfy expressions (F) and (G) to convert magnification of the optical system in a subsidiary scanning direction to thereby change resolution of the recording image from α (dpi) to β (dpi)
b=fS1+fS2 (F) |fS2/fS1|=β/α (G)
in which b is a distance between principal surfaces of the cylindrical lenses, fS1 is a focal length of the front lens, and fS2 is a focal length of the rear lens.

11 more elements

Dependencies are inferred from the claim text.