Minolta Company, Ltd.

Minolta Camera Kabushiki Kaisha

Konica Minolta Business Technologies, Inc.

Hiromu Nakamura

Satoru Ono

Akiyoshi Hamada

Toshio Naiki

Etsuko Shibata

Jun Kohsaka

Hidenari Tachibe

Kunihiko Omura

Tetsuji Niikawa

Masanori Murakami

Toshihiko Ueda

Nobuo Kanai

Masanori Yamamoto

Yasushi Nagasaka

Muneo Kuroda

Haruhiro Hyodo

Koji Ohashi

Shinya Sakanashi

Hiroaki Nakauchi

Masahito Niikawa

Hisashi Yasumatsu

Takayoshi Mori

Masanori Mirakami

Michio Yamada

Koji Ooi

A drawing method for forming a reflective curved surface by pressing a metal plate fitted in a fixed die with a movable die. The fixed die is composed of a lower die and a core, and the movable die is composed of an upper die and a presser. During the drawing, the metal plate is pressed to have a compressed border portion between a non-pressed portion and a curved surface pressed portion. It is the most desirable to compress the border portion to have a thickness which is 70% of the thickness of the metal plate before drawing.

Drawing method and drawing die assembly

The light beam scanning device has a casing injection molded from magnesium or magnesium alloy as the material. A polygon mirror and a motor are sealed in the inside of the casing and a cover covering the latter. Since the thickness of the magnesium or magnesium alloy material can be reduced, heat generated from a motor is dissipated satisfactorily. Heat dissipating fins are formed to the casing to promote heat dissipation and enhance the strength of the casing.

Optical beam scanning device

A scanning apparatus has a luminous flux deflector and a single f.theta. lens. The deflector deflects a convergent luminous flux on a scanned surface at a uniform angular velocity. The f.theta. lens is arranged between the deflector and the scanned surface. The f.theta. lens is bi-convex in a main scanning direction and is made of a material having a refractive index of at most 1.6. One surface of the f.theta. lens in a main scanning direction is so curved that a radius of curvature in the main scanning direction A decreases as an angle of view in the main scanning direction increases.

Image forming light scanning apparatus

A laser beam scanning device which has an improved cylindrical mirror in an optical path from a laser source unit to a polygonal mirror. The cylindrical mirror has a finite radius of curvature only in a sub scanning direction, and the radius of curvature in the sub scanning direction varies in a main scanning direction such that the closer to a laser beam incident side, the larger and the closer to a laser beam emergent side, the smaller. The laser beam reflected by the cylindrical mirror is converged on a line substantially parallel to each reflective facet of the polygonal mirror.

Laser beam scanning device and apparatus provided with a laser beam

A scanning apparatus has a luminous flux deflector and a single f.theta. lens. The deflector deflects a convergent luminous flux on a scanned surface at a uniform angular velocity. The f.theta. lens is arranged between the deflector and the scanned surface. The f.theta. lens is bi-convex in a main scanning direction and is made of a material having a refractive index of at most 1.6. One surface of the f.theta. lens in a main scanning direction is so curved that a radius of curvature in the main scanning direction decreases as an angle of view in the main scanning direction increases.

A scanning lens system forms into an image a deflected beam having its object point in the main scanning direction located at a finite distance to scan a scanned surface. The fourth surface is parallelly decentered in the main scanning direction relative to the optical axis passing the center of a main scanning direction scanning width on the scanned surface. The third and fourth surfaces are rotatively decentered relative to the optical axis about an axis parallel to the sub scanning direction.

Scanning lens system

A laser beam optical scanning system having a laser diode, a collimator lens, a cylindrical lens, a polygonal mirror and an f.theta. mirror. The f.theta. mirror has a free toric surface whose curvature in the main scanning direction varies in accordance with field angle. The variation of the curvature of the free toric surface is set in accordance with the position of the f.theta. mirror in the optical path, and this appropriate setting of the variation of the curvature enables the f.theta. mirror to correct both distortion and curvature of field in the main scanning direction.

Light beam optical scanning system having an f.theta. mirror

A light beam scanning optical apparatus which deflects a light beam emitted from a light source with a polygonal mirror and scans the light beam on a photosensitive member through an f.theta. optical system. Suppose the distance between a rotation axis of the polygonal mirror and each reflecting facet in a case wherein the reflecting facets are flat to be A. If a convergent light beam is incident to the polygonal mirror, and if the reflecting facets are concave, the distance between the rotation axis and the facets is adjusted to be larger than A. If the reflecting facets are convex, the distance is adjusted to be smaller than A. Also, if a divergent light beam is incident, and if the reflecting facets are concave, the distance between is adjusted to be smaller than A. If the reflecting facets are convex, the distance is adjusted to be larger than A.

Polygonal mirror and manufacturing method thereof and light beam

A laser beam optical scanning device which has a laser diode, a collimator lens, a cylindrical lens, a polygonal scanner and an f .theta. lens. The polygonal scanner is made of resin, and when the polygonal scanner is driven to rotate, the reflective facets of the polygonal scanner are distorted to be concave or convex because of a centrifugal force. If the reflective facets are distorted to be concave with rotation of the polygonal scanner, the image surface shifts along the optical axis toward the polygonal scanner. Therefore, in this case, the elements of the optical scanning device are positioned such that the image surface is located behind a light receiving surface while the polygonal scanner is stationary and is located nearer to the light receiving surface while the polygonal scanner is rotating.

Laser beam optical scanning device

An optical device having an optical element, a base plate which has a mount surface for setting the optical element, a first holding member composed of at least a hole and a projection so as to permit the optical element mounted on the base plate to move longitudinally and a second holding member composed of a hole and a projection so as to restrain the optical element from moving in a direction orthogonal to an optical axis.

Optical device

An optical device comprises an optical lens and a mounting assembly for securing the optical lens to a support surface. The optical lens has a longitudinal axis and has first and second projections; the mounting assembly includes a clamp member which has a clamp surface and depresses the optical lens downwardly through contact of the clamp surface with the optical lens so as to mount the optical lens on the support surface. The clamp member is formed, on the clamp surface, with first and second holes engageable with the first and second projections of the optical lens, respectively; the second hole is an elongated opening extending in the longitudinal direction of the optical lens.

Optical device having an optical lens and a mounting assembly

A laser beam optical scanning device including a housing, a light source for emitting a unidirectional laser beam, polygonal mirror for deflection scanning a laser beam emitted from the light source within a single plane, and optical members for directing the deflected scanning laser beam on the surface of a photosensitive member through a beam emission aperture of the housing. A transparent member is provided at the beam emission aperture of the housing so as to satisfy the following equation: ##EQU1## where X:distance (mm) from transparent member to surface of photosensitive member,

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Toyokawa, Japan

Hiromu Nakamura