Hitachi, Ltd.

Hitachi Koki Co., Ltd.

Other

Hitachi Cable, Inc.

Ricoh Printing Systems, Ltd.

Seiji Maruo

Shinya Kobayashi

Nobuyoshi Hoshi

Akira Arimoto

Toru Miyasaka

Masashi Yamamoto

Susumu Saito

Hiroyuki Mabuchi

Teruaki Mitsuya

Tatsuya Sugita

Kenichi Ito

Shinichi Akatsu

Hisao Okada

Kunio Sato

Atsushi Onose

Shin'ichi Nakatsuka

Yoshito Tsunoda

Takao Umeda

Juhyun Yu

Yasuro Hori

Yasuo Takuma

Mamoru Okano

Takao Kumasaka

Shinichi Nakatsuka

Ryuta Takahashi

Ryuuichi Shimizu

Masayoshi Ishii

Yoshihito Maeda

Yasuaki Suzuki

Kazutoshi Obara

Hiroki Katayama

Kunio Satoh

Noribumi Kobayashi

Susumu Edo

Yuuki Naganuma

There is provided a filter assembly for combining a wavelength multiplexed optical signal by multiplexing optical signals of different wavelength emitted from respective optical devices, and/or for dividing a wavelength multiplexed optical signal into optical signals of different wavelength and causing the optical signals of different wavelength to enter respective optical devices. This filter assembly comprises: a light transmitting member within which each optical signal propagates; plural optical filters disposed on an upper face of the light transmitting member at a predetermined spacing wherein each optical signal passes through the optical filters; upper reflective layers respectively provided between adjacent ones of the optical filters; and a lower reflective layer provided on a lower face of the light transmitting member, and wherein the wavelength multiplexed optical signal propagates along the same optical path within the light transmitting member.

Filter assembly and optical module using same

A multi-beam image recording device is capable of recording high-quality high-resolution images without positional errors by exposing test patterns for measuring positional errors of beam spots of each laser beam in main and subsidiary scanning directions, calculating the positional errors of beam spots using a correcting device, controlling the quantity of exposure according to the result of calculation, and thus correcting the positional errors in main and subsidiary scanning directions.

Image recording device and an image recording system

An electro-photographic apparatus includes a photosensitive body in the form of a photosensitive belt disposed for movement along a path in which a major portion of the path extends in a substantially vertical direction, and a plurality of developing units arranged in a vertical stack along one side of the substantially vertical path of the photosensitive body. A transfer unit is disposed adjacent to another side of the substantially vertical path of the photosensitive body, a fixing unit and a paper cassette are provided. A first transporting path is provided along which the print medium is transported in a substantially vertical direction from the paper cassette to the fixing unit via the transfer unit.

Small-size color electro-photographic apparatus

An electro-photographic apparatus having a photosensitive body, a plurality of developing units for forming a toner image on a surface of the photosensitive body by attaching toner on a surface of the photosensitive body, a member for receiving a print medium, a first transporting path including a printing portion for transferring one toner image in a substantially vertical direction from the photosensitive body onto one side of the print medium and a fixing portion for fixing the transferred image so as to have a printed print medium and a second transporting path disposed substantially in parallel to and coupled to the first transporting path for returning the printed print medium to the first transporting path for enabling transfer of another toner image on an opposite side on the printed print medium. The printed print medium is transported along the first transporting path for fixing the transferred image on the opposite side of the printed print medium by the fixing portion. The developing units are vertically stacked.

An image memory for storing input image data by plural lines, a horizontal scanning fringe correction exposure determining section for determining a fringe between close vertical lines in a horizontal scanning direction in the image data, a vertical scanning fringe correction exposure determining section for determining a fringe at the lower end of an image in a vertical scanning direction and a switch for selecting at least three laser drivers are provided.

Electrophotographic printer having an image memory, a horizontal scanning fringe correction exposure determining section, a vertical scanning fringe correction exposure determining section, and a switch

An electrophotographic printing apparatus using electric potential dividing development processing without the occurrence of primary fringe and fringe caused by auxiliary exposure has reverse electric fields causing primary fringe and fringe caused by auxiliary exposure adjusted to be nearly equal to each other. The auxiliary exposure is applied to an area surrounding one image, and an electric potential of an intermediate electric potential zone is brought close to a bias electric potential of another image which is not subjected to auxiliary exposure. Further, a white portion to produce a reverse electric potential therein at the rear end of an electric potential portion to be developed with toner, relative to a rotating direction of a developing roller, is exposed with a light intensity forming an electric potential between an electric potential developing an image with toner and the intermediate electric potential, and portions at the front end and the sides are exposed with a light intensity forming the intermediate electric potential.

Electrophotographic printing apparatus using electric potential dividing

An electro-photographic apparatus including a photosensitive body, a plurality of developing units for forming a toner image on a surface of the photosensitive body by attaching toner on the surface of the photosensitive body, an intermediate transfer body for having the toner image transferred thereon and for transferring the toner image onto a print medium, and a paper cassette for containing the print medium. The paper cassette and the developing units are arranged to be horizontally detachable in the same direction.

A laser beam printer is provided which is capable of compensating for the difference in diameter between dots every colors and preventing unintentional coloring of the boundary between colors. In a conventional light source used for a printer, a spot diameter thereof is small upon low output and large upon high output. However, in a semiconductor laser device of the present invention, which is used for a light source for a printer, the spot diameter of the light source is controlled so as to be large upon low output and small upon high output. It is thus possible to keep the spot diameter of the laser light source constant. As a result, an irregular color-free laser beam printer can be materialized.

Laser beam printer and semiconductor laser device suitable for a light

A light beam scanning apparatus in which laser power and spot shape of an emitted laser beam are controlled, has a laser control signal generating part for changing a picture signal to a laser power control signal and a spot shape control signal, a laser power control current generating part which is driven by the laser power control signal, a spot shape control current generating part which is driven by the shape control signal, and a laser beam emission part for emitting a laser beam having a laser power and a spot shape which are controlled by the control signals via a commonly used light wave guiding part, wherein the control signal generating part generates or corrects the control signals based on at least one of the difference between the laser power of a beam to be emitted and a detected laser power, the difference between the spot shape of a beam to be emitted and a detected laser power, a detected temperature at the laser beam emission part, and an effective light emission pixel number.

Light beam scanning apparatus which controls power and spot shape of

In the tri-level process in which positive and negative latent images are formed on a photosensitive body and then developed using toners of two colors (for example, red and black) charged respectively to opposite polarities with respect to the polarities of the latent images, there has been a problem of degrading the quality of a two-color picture by the appearance of a special phenomenon in which red toner is attached around a black image and black toner is attached around a red image by attraction of the reverse electric field. An exposure control is performed in order to suppress the fringe phenomenon.

Light exposure controlling method of electrophotographic apparatus for

An electrostatic recording apparatus includes a background potential detector (12a, 12b, 13a and 13b) for detecting the potential (VMc) of a background region adjacent to a normal development region (having VHc) and the potential (VMd) of a background region adjacent to a reversal development region (having VLd), and a controller (25) for controlling a charge voltage, exposure intensity, and/or developing bias voltage according to the output of the background potential detector to eliminate a fogging phenomenon.

Electrostatic recording apparatus and electrostatic recording method

A color electro-photographic apparatus including a photosensitive belt disposed for movement along a path in which a major portion of the path extends in a substantially vertical direction, a plurality of developing units arranged in a stack along one side of the photosensitive belt, and an intermediate transfer body disposed adjacent an other side of the photosensitive belt at a lower portion thereof. The color electro-photographic apparatus also includes a paper cassette extending in a horizontal direction at a part of the apparatus below the photosensitive belt so that paper travels from an end of the paper cassette along a vertical path without bending back upon itself prior to image transfer by the intermediate transfer body.

Color electro-photographic apparatus

A semiconductor laser device is disclosed, in which two semiconductor layers of different conduction types are formed on a semiconductor substrate, an active semiconductor layer having a forbidden band width narrower than the two semiconductor layers is formed between the two semiconductor layers, and a waveguide encloses the light in a plane parallel to the active layer. The waveguide includes at least two regions of different widths. The wider one of the waveguide regions is located in the vicinity of the end surface of the semiconductor laser. A relation holds that .pi./6&lt;L.times.(K.sub.0 -K.sub.2) &lt;.pi..times.5/6, where L is the length of the wider waveguide region, and K.sub.0, K.sub.2 are propagation constants of the zeroth-order and second-order transverse modes, respectively, propagating in the waveguide.

Semiconductor laser device and optical printing apparatus using the same

An electrophotographic image recording apparatus that forms an electrostatic latent image so that the uniformly charged surface of a photoreceptor is scanned for its exposure with a beam spot of a light beam generated according to image information, to discharge the surface of the photoreceptor up to a medium potential. The electrophotographic image recording apparatus includes a light beam generator capable of varying an amount of light beam and a light intensity distribution pattern of a beam spot on the surface of the photoreceptor, an intensity distribution pattern controller for controlling the light beam generator according to the image information of peripheral pixels, to vary the intensity distribution pattern of the beam spot on the surface of the photoreceptor, and a light beam output controller for controlling the light beam generator to put the exposure energy on pixels, exposed to the beam spots of intensity distribution patterns, at a predetermined value.

Electrophotographic image recording apparatus with photoreceptor

An optical arrangement for an optical scanning apparatus which can record a plurality of high precision information concurrently, provides for a laser beam emitted from a single light source to be polarized in two polarization directions, and each of the two polarized beams is further imparted with different information according to its polarization direction. Then, the two polarized beams are used for scanning over a photosensitive member to concurrently record respective information at different positions on the photosensitive member. In order to suppress induced light fluctuation depending on an incident angle of light on the beam splitter, an optical rotation means is provided in the optical system, such that a desired optical rotation control can be obtained corresponding to the incident angle on the beam splitter, so as to compensate for the fluctuation of light whereby the beam splitter can be arranged to be free of the influence of the incidence angle of the beam.

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Hitachi, Japan

Seiji Maruo