Hitachi, Ltd.

Hitachi Koki Co., Ltd.

Yoshifumi Homma

Kimio Tatsuno

Shoichi Ito

Yoshifumi Ono

Susumu Saito

Keiji Kataoka

Isamu Terashima

Kazuo Kikuchi

Masafumi Suzaki

Yousuke Nagano

Mitsugu Asano

Tsugio Kikuchi

Kenichi Ebata

Jinichi Hongou

An electrophotography printer includes a drum formed of a non-magnetic cylindrical body having an outer circumferential surface to which a photosensitive material is applied, end brackets attached to opposite ends of the drum, and a drum shaft for transmitting a driving torque to the drum. A connection structure between the drum and the drum shaft includes end bracket shafts provided on the end brackets, a hole formed in the drum shaft so as to be capable of engaging with one of the end bracket shafts, parallel pins provided on the end bracket shafts so as to be perpendicular to the axes thereof, and at least one taper groove formed in an end portion of the drum shaft. When the drum is housed, one of the parallel pins and the taper groove engage with each other while the whole of the drum is pressed toward the drum shaft by an elastic member, thereby reducing the non-uniformity of the rotation of the drum.

Drum driving unit of electrophotography printer

An optical scanning apparatus includes a light source, an image forming optical unit, a deflection unit and an optical beam detection unit provided inside a deflection area of the optical beam, the optical beam detection unit receiving the optical beam and generating a synchronizing signal. The optical beam detecting unit includes a unidirectional converging optical unit. This unidirectional converging optical unit is provided on an optical path of the optical beam irradiating the scanned surface for further converging the optical beam in a direction perpendicular to the direction of scanning in addition to the convergence performed by the image forming optical unit, so that the optical beam irradiating a light receiving surface of the optical beam detection unit can be focused in advance of the light-receiving surface of the optical beam detection unit in the above direction. In consequence, the allowable range of a shift of the scanning path of the optical beam caused by the manufacturing errors of the deflection unit and of a shift of an optical axis caused by the fine adjustment errors or strains of the supporting members can be increased. It is thus possible to provide an optical beam scanning apparatus which has a simple configuration and which enables the accuracy with which the position of the optical beam is detected to be improved.

Optical scanning apparatus

A laser beam printer, in which a laser beam outputted by a laser diode pulse-modulated and controlled is deviated to be swept by means of a polygon mirror and folded by a reflecting mirror, after having passed through an F.theta. lens including two single lenses, so that it traverses the space between the two single lenses and reaches a light sensitive drum in order to expose it thereto.

Light beam scanning device and electronic photographic recording device

An optical scanning system wherein a light beam from a laser source is reflected by a rotating polygonal mirror and focused by a scanning lens into a scanning beam spot on the drum surface. A cylindrical lens disposed between the scanning lens and the drum for correcting the unevenness of the scanning line pitch caused by the incline of the each facet of the polygonal mirror has a curvature in the scanning direction of the beam so that optimal focal points of the scanning beam spot align on a straight line.

Optical scanning system

In a laser beam scanner apparatus for scanning the surface of a photosensitive drum or a document to be read by deflecting a laser beam emitted from a laser diode with a deflector, there is provided a drive current control circuit for controlling the magnitude of drive current of said laser diode on the basis of a beam deflection angle of said deflector.

Laser beam scanner apparatus

An apparatus for driving a semiconductor laser for use in a laser-beam printer, in which a laser beam from the laser is deflected so as to scan a light-sensitive drum and a light-sensitive detector placed in the vicinity of one edge of the drum, comprises a first device for determining the operation level for the laser when it scans the drum to record information thereon, a second device for determining the operation level for the laser when it scans the detector to provide a scanning start pulse signal and a controller for controlling the first and second devices so that they are alternately enabled to determine the intensity of the laser beam depending upon whether the drum or the detector is scanned, whereby the intensity of the laser beam is allowed to be adjusted in accordance with the varying light-sensitivity of the drum without fluctuating the instant of generation of the scanning start pulse signal.

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Hitachi, Japan

Yoshifumi Homma