Ricoh Company, Ltd.

Kenichi Takanashi

Seizo Suzuki

Yoshinori Hayashi

Taira Kouchiwa

Takao Yamaguchi

Hiroyuki Suhara

Magane Aoki

Takeshi Ueda

Tatsuya Ito

Satoru Itoh

Koji Hirakura

Yasushi Takahashi

Atsushi Kawamura

Hiromichi Atsuumi

Nobuo Sakuma

Akihisa Itabashi

Seizoh Suzuki

Tomohiro Nakajima

Kohji Sakai

Daisuke Ichii

Kan Tomita

Nobuaki Ono

Tomoya Ohsugi

Yoshio Fukushima

Osamu Endo

Toshiro Ozawa

Takayuki Ohsawa

A light source system includes a splitter that split light beams Femitted from a light source into at least light beams FM and light beams FS, and an optical detecting system that guides the light beams FM to a detector. A light component near a light-intensity peak of the light beams Fin a plane perpendicular to a propagation direction of the light beams Fis included only in the light beams FS. Accordingly, light beams have a substantially circular or elliptic cross section with the intensity peak near the center. Light at the peak is supplied to the outside, and other light is used to control an amount of light.

Light source system, optical scanner, image forming apparatus, and light-amount control method

An optical scanning lens is used in a scanning and image forming optical system which gathers a light flux deflected by a light deflector in the vicinity of a surface to be scanned. The lens is formed by plastic molding of polyolefin resin, and the following condition is satisfied: 0&#x3c;|&#x394;n(x)&#x2212;min[&#x394;n(x)]|&#x3c;34&#xd7;10, where &#x394;n(x) denotes a refractive-index distribution existing inside the lens, in a range which the light flux passes through, in the lens, and min[&#x394;n(x)] denotes the minimum value of the &#x394;n(x).

Optical scanning lens, optical scanning device and image forming apparatus

An optical scanning device condenses a beam deflected by a light deflector, by a scanning and imaging lens toward a surface to be scanned to form a beam spot thereon, and scans the surface to be scanned by the beam spot. At least one lens of the scanning and imaging lens is configured so that a lens body thereof is held by a holding frame, wherein a rib surface at an end in a longitudinal direction of the holding frame is inclined so that a ghost light generated as a result of the deflected beam being reflected by the end in the longitudinal direction of the holding frame is changed in light path in a sub-scan direction.

Optical scanning device, image forming apparatus, and optical scanning method

An optical scanning lens which is used in a scanning and age forming optical system which gathers a light flux deflected by a light deflector in the vicinity of a surface to be scanned. The lens is formed by plastic molding of polyolefin resin, and the following condition is satisfied: 0&#x3c;|&#x394;n(x)&#x2212;min[&#x394;n(x)]|&#x3c;34&#xd7;10, where &#x394;n(x) denotes a refractive-index distribution existing inside the lens, in a range which the light flux passes through, in the lens, and min[&#x394;n(x)] denotes the minimum value of the &#x394;n(x).

An optical scanning lens used in a multi-beam scanning optical apparatus including a first mechanism reforming the light beams into line images, a deflecting mechanism reforming the light beams into multiple scanning beams, and a second mechanism reforming the multiple scanning beams into scanning light spots running on a recording surface. The optical scanning lens has a refractive index profile and is included in the second optical mechanism, and satisfies a formula (m&#x2212;1)&#xd7;PLs&#xd7;V/WLs&#x2266;2.3&#xd7;10, where m is a number of light emission points, PLs is a pitch of the multiple beams, V represents the refractive index profile, W [mm] represents an effective recording width of the recording surface, and WLs represents an effective range of the optical scanning lens in the sub-scanning direction corresponding to the effective recording width W. An optical scanning apparatus or image forming apparatus may use the optical scanning apparatus.

Optical scanning lens and apparatus capable of effectively generating accurately-pitched light spots, and image forming apparatus using the same

An optical scanning apparatus includes light sources, an aperture having, and coupling lenses. Numbers of the light sources and the coupling lenses are equal to each other and the apparatus satisfies an inequality 12.7 &#x3c;(D&#xd7;&#x3b2;&#xd7;m&#xd7;xdpi)/(2&#xd7;NA) &#x3c;38.1 and an equation &#x3b2;=(&#x3b2;&#x2212;&#x3b2;)/(n&#x2212;1), wherein D represents a width of the slit of the aperture, &#x3b2;represents a beam open angle, mo represents a total lateral magnification ratio, dpi represents a number of dots per inch, NA represents a numerical aperture, &#x3b2;represents a positive open angle, &#x3b2;represents a negative open angle, and n represents the number. Further, an image forming apparatus using this optical scanning apparatus and an image forming method are provided.

Method and apparatus for multi-beam optical scanning capable of effectively adjusting a scanning line pitch

Method and apparatus for optical scanning capable of performing a high speed and high pixel density scanning

An optical scanning lens is used in a scanning and image forming optical system which gathers a light flux deflected by a light deflector in the vicinity of a surface to be scanned. The lens is formed by plastic molding of polyolefin resin, and the following condition is satisfied: 0<&verbar;&Dgr;n(x)&minus;min&lsqb;&Dgr;n(x)&rsqb;&verbar;<34&times;10 , where &Dgr;n(x) denotes a refractive-index distribution existing inside the lens, in a range which the light flux passes through, in the lens, and min&lsqb;&Dgr;n(x)&rsqb; denotes the minimum value of the &Dgr;n(x).

A multi-beam scanning apparatus performs image scanning by emitting multiple beams from a plurality of light sources, which beams are deflected by a common deflector at equiangular velocity. The beams are then condensed by a common scanning image forming lens so as to form optical spots on a scanning surface. As a result, the plurality of lines are simultaneously scanned by the beams on the scanning surface at a substantially constant velocity. Characteristics of the light sources, such as the wavelength thereof, and other factors such as writing density and desired writing width of a writing line, are arranged to eliminate differences in a written vertical line in a sub scanning direction caused by a magnification difference, regardless of the cause of such differences. In addition, the modulation frequency of the plurality of light sources is made different from each other so that writing widths of the dots written by the plurality of light sources become the same.

Multi-beam scanning apparatus

An optical scanning device includes a light source, a coupling lens, an optical deflector, an aperture and a scanning image-forming optical system. The central wavelength of the light flux emitted by the light source is less than about 680 nm, and NAO, &kgr;, &bgr;,satisfy &bgr;,/(NAO&bull;&kgr;)<100, and NAO satisfies 0.18<NAO<0.35, where: NAO represents the light-source-side numerical aperture of the coupling lens; &kgr; represents the ratio A/D of the larger diameter A of the diameters, in a main scanning direction and a sub-scanning direction, of the opening of the aperture relative to the diameter D of the light flux emitted from the coupling lens; and &bgr;,represents the larger one of the lateral magnifications, in the main scanning direction and the sub-scanning direction, of the entire optical system with respect to an optical path extending from the light source to the surface to be scanned, and including a point of the image surface, at which point the image height is 0.

Optical scanning device, image forming apparatus and optical scanning method

An optical scanner having a light source for emitting a light beam, an optical deflector having a deflecting-reflecting face for deflecting the light beam at a constant angular speed and a scan image forming mirror for reflecting the deflected light beam to a surface to be scanned at a constant speed. The light source and the optical deflector are provided on opposite sides across the scan image forming mirror and the light beam is illuminated toward the deflecting-reflecting face of the optical deflector through an emitted-light transmitting portion provided outside an effective area of the scan image forming mirror.

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Chiba, Japan

Kenichi Takanashi