Minolta Camera Kabushiki Kaisha

Minolta Company, Ltd.

Nisca Corporation

Nippon Seimitsu Kogyo Kabushiki Kaisha

Akiyoshi Hamada

Toshio Naiki

Mitsutoshi Yagoto

Yoshihiro Inagaki

Hiromu Nakamura

Masanori Murakami

Yutaka Watanabe

Satoru Ono

Yutaka Tanaka

Masayuki Mino

Shinichi Mori

Kunihiko Omura

Shuji Mochizuki

Hiroaki Nakauchi

Kyoji Tachikawa

Toshihiko Ueda

Nobuo Kanai

Haruhiro Hyodo

Muneo Kuroda

Kazuyuki Yoshida

Keiji Ogoh

Katsumi Miwa

Keijiro Sakamoto

Masahito Niikawa

A multi-beam optical scanning device capable of suppressing jitter at the image edges within allowable tolerance by satisfying the following equation: ##EQU1## Where r represents the radius of photosensitive member (mm); .alpha. represents the maximum value of the angle obtained by subtracting the angle formed by the light beam and the scanned line on the surface of the photosensitive member from 90 degrees; D represents the distance (mm) on the surface of the photosensitive member between the light beam condensing position on the furthermost upstream side and the condensing position on the furthermost downstream side in the direction of rotation of the photosensitive member.

Multi-beam optical scanning device

A light beam scanning optical apparatus in which is capable of switching over the image density. The light beam scanning optical apparatus comprises a light source unit having at least three light emitting points, a control circuit block which selects and lights the light emitting points for switching over the image density at least either between different pages or within one page, an optical deflector for deflecting light beams emitted from the light emitting points, a scanning surface, a first optical system placed between the laser diode array and the optical deflector, and a second optical system placed between the optical deflector and the scanning surface. For switching over the image density, light emitting points corresponding to a specified image density are selected and lighted by the control circuit block. Thus, the switchover of image density in the direction of sub scanning is implemented not by mechanical operation of relatively slow response, but by electrical operation of quick response with selection of light emitting points.

Light beam scanning optical apparatus

A light beam scanning optical apparatus is provided which simultaneously converges a plurality of light beams on different locations in a scanning surface and thereby simultaneously writes a plurality of lines in one scanning operation. The light beam scanning optical apparatus comprises a light source having three or more light emitting points, and a converging lens which shapes light beams emitted from the light source, into generally parallel or convergent bundles of rays. The converging lens has a shape generally symmetrical with respect to the optical axis, and the light emitting points on the light source are disposed on a circle having its center generally on the optical axis. Alternatively, the light source comprises a first light source having one light emitting point, a second light source having a plurality of light emitting points, and a light beam coupling device for unifying the directions of travel of light beams emitted from the first and second light sources. Scanning with light beams of which the number is n and which have been emitted from the light source is simultaneously performed at unequal intervals with respect to the direction of sub scanning on the scanning surface, and then the following relational expressions hold:

Light source device and light beam scanning optical apparatus

A laser diode array unit for use in laser beam scanning optical apparatus and the like. The laser diode array has plural light emitting sources to be drivingly controlled independently of each other. The laser diode array is so disposed as to permit laser beams emitted from the light emitting sources to be incident to a collimator lens. On an optical axis between the laser diode array and the collimator lens is disposed a beam splitter for splitting the laser beams emitted from the light emitting sources into image light and monitor light. A magnifier lens and a photoreceptor element are arranged on the optical axis so as to allow incidence of monitor light oriented to advance in a direction perpendicular to the direction of advance of image light.

Laser diode array unit

A light beam scanning optical apparatus which writes two lines at one scan on a photosensitive member with light beams emitted from two light sources. A light source unit of the apparatus has a first movable retainer block which retains a first laser diode and a second movable retainer block which retains a second laser diode. The second movable retainer block becomes adjustable two-dimensionally on a base block by loosening screws which fit the second movable retainer block to the base block.

An optical unit provided between a plurality of light sources and a deflecting system in a multiple beam scanning optical system in which the appropriate intensity and appropriate intensity distribution of each beam on the scanned surface change are maintained regardless of foreseen changes in ambient temperature. The optical unit includes a condenser lens which condenses the beams emitted from the light sources and an aperture which regulates diameters of beams projected from the condenser lens. A connecting member which connects the condenser lens and the aperture at a distance corresponding to a focal length of the condenser lens. The connecting member is formed of material or materials whose amount of linear expansion per unit of temperature is approximately equal to an amount of change in the focal length of the condenser lens per unit of temperature

Multiple beam scanning optical system

A scanning optical apparatus has a convex cylindrical lens and a concave cylindrical lens between a light source for emitting a light beam and a polygon mirror. The cylindrical lenses condense the light beam in the vicinity of a deflecting surface of the polygon mirror only in the sub-scanning direction. The cylindrical lenses are held by a lens barrel to form one unit, and the lens barrel is mounted on a V groove formed in a base. The position of the unit having the cylindrical lenses is adjustable along the optical axis, and the rotational angle of the unit is adjustable about the optical axis.

Lens holding apparatus and a light-beam scanning optical apparatus

A multi-beam emitting device which splits a light beam emitted from a light source into a plurality of beams with a beam splitter to emit a plurality of beams. As the beam splitter, an optical waveguide type acoustooptic element or the like is used. A multi-beam emitting device according to the present invention has a beam splitter which drives an acoustooptic element with a plurality of electric signals with different frequencies applied thereto so as to deflect a light beam emitted from a light source and split the light beam into a plurality of beams, a signal generator which generates the electric signals with different frequencies which are used for the drive of the acoustooptic element, a modulating circuit which turns on and off the electric signals generated by the signal generater individually based on a data signal, an intensity control circuit which controls the light source to change the intensity of the light beam emitted therefrom. Another multi-beam emitting device has a beam splitter which deflects a light beam emitted from a light source and splits the light beam into an even number of beams, a shutting member which shuts out a half of the beams, a modulating circuit which controls the beam splitter so that the total quantity of light of the beams which are emergent from the beam splitter and not shut out by the shutting member and the beams which are emergent from the beam splitter and shut out by the shutting member will be constant. Further, in these multi-beam emitting devices, the deflecting position of the light beam and the beam waist position of the light beam are inside the optical waveguide type acoustooptic element at a specified distance from each other.

Multi-beam emitting device having an acoustooptic element

A scanning optical apparatus for a printer and a digital copying machine has a light source, a deflector, first and second imaging units. The deflector deflects a light beam emitted from the light source to a main scanning direction. The first imaging unit makes the light beam emitted from the light source form an image in the vicinity of the deflection position of said deflector in the sub-scanning direction. The first imaging unit has a first resin lens having a negative refractive power only in a sub-scanning direction. The second imaging unit makes the light beam deflected by the deflector form an image on a scanned surface in the sub-scanning direction. The second imaging unit has a second resin lens having a positive refractive power only in the sub-scanning direction.

Scanning optical apparatus

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 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

A toroidal mirror reflects a light beam deflected by a deflection device with a mirror plane curved in a scanning direction and leads a spot of the light beam so as to move substantially at a uniform velocity on a light receiving surface.

Beam scanning optical system

A laser source unit in which a laser diode is located at a focal point of a Fresnel lens using refraction and diffraction. The laser diode emits a laser beam in accordance with a control signal generated by a driving circuit. The laser diode is driven such that defocus on an image surface caused by a rise in the temperature of the laser diode can be kept in a tolerable degree.

Laser beam optical scanning system and laser printing provided with the

A beam scanning optical system having a semiconductor laser for emitting a light beam; a cylindrical lens for converging the laser beam into a straight line; a polygon mirror for deflecting the laser beam which converged the cylindrical lens at a constant angular velocity; a spherical mirror for collecting the deflected laser beam on a surface of a photosensitive member; and a lens disposed between the polygon mirror and the spherical mirror, the lens having at least one toroidal surface. The lens is so disposed that its beam entrance side and beam exit side are decentered in a direction of the beam scanning, and curvature of the entrance side and curvature of the exit side on a plane of deflection have different centers. The entrance side and the exit side of the lens are a toroidal surface and a spherical surface respectively, and the spherical surface is decentered in a direction perpendicular to the plane of deflection in respect to the toroidal surface. Also, the spherical mirror is decentered in a direction perpendicular to the plane of deflection.

An image recording apparatus wherein a laser diode which is disposed on a focal point of a micro Fresnel lens emits a laser beam and the laser beam is collimated by the Fresnel lens and scanned on a photosensitive drum by a polygonal mirror and an f.theta. optical system. A change in temperature of the laser diode does not result in such serious defocus as to cause practical problems.

Growing community of inventors

Toyokawa, Japan

Akiyoshi Hamada