Minolta Company, Ltd.

Minolta Camera Kabushiki Kaisha

Satoru Ono

Hiromu Nakamura

Toshio Naiki

Etsuko Shibata

Akiyoshi Hamada

Jun Kohsaka

Kunihiko Omura

Masanori Murakami

Yasushi Nagasaka

Masahito Niikawa

An optical member having a toric functional surface has a marking which is made by a configuration of a mold used to form the optical member. The marking is formed in the optical member outside an effective area of the functional surface of the optical member. In one embodiment, the optical member is an optical member for a scanning optical system.

Optical member

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 optical system is provided with a scanning lens which images a luminous flux deflected by a deflector at a constant angular speed on a surface to be scanned so that the luminous flux scans the surface to be scanned substantially at a constant speed. At the cross section in the main scanning direction, the luminous flux incident on the scanning lens is a convergent light beam, and the scanning lens includes from the deflector side a first lens of a positive paraxial refractive power and a second lens of a negative paraxial refractive power.

Scanning optical system

A scanning optical system has a deflector and a scanning lens. A convergent beam is deflected at a uniform angular velocity by the deflector. The scanning lens forms the scanned beam into an image on a scanned surface to scan the surface substantially at a uniform velocity. The scanning lens includes from the side of the deflector a negative lens element and at least one more lens element. The convergent beam is incident on a surface of the deflector which faces the deflector. The scanning lens fulfills predetermined conditions.

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 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

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,

A laser beam light source device which has Fresnel lens having grating of unequal spacing and facing a laser diode, and condenser lens made of resin. The focal length of the condenser lens is set at a value which nullifies changes in the focal length of the Fresnel lens induced by fluctuations in the oscillation wavelength of the laser diode accompanying temperature change, and changes in the focal length of the Fresnel lens accompanying temperature change. Further a laser beam scanning optical system for scanning on a scan line via a deflecting device and optical elements by a laser beam emitted from a laser light source based on image information. In the laser scanning optical system, a pair of anamorphic lenses are disposed anteriorly and posteriorly to the deflecting device to correct surface tilt of the deflecting device, one of the anamorphic lens being a Fresnel lens, another of the anamorphic lens being made of resin.

Laser beam optical system capable of compensating focal length changes

An optical apparatus includes a laser beam emitter for outputting a laser beam modulated in accordance with image information, and a lens unit resting on a lens mount. The lens unit includes, all formed integral with one another, an effective lens portion, a cylindrical portion surrounding a side surface of the effective lens portion, and projections extending from peripheral positions of the cylindrical portion. The lens mount includes a holder for holding the cylindrical portion of the lens unit to be rotatable and axially slidable on an optical axis of the laser beam, and a groove formed in the bottom of the holder for receiving the projection.

Growing community of inventors

Toyokawa, Japan

Satoru Ono