Kabushiki Kaisha Toshiba

Other

Ken Omura

Takashi Shiraishi

Masao Yamaguchi

Naruhito Yoshida

Yutaka Yoshida

Kimiaki Furukawa

Yoshitsugu Nakatomi

Tsuyoshi Todome

Hiroshi Kaneko

Seiichiro Fushimi

Koichi Hiruta

An image forming apparatus is provided with a table unit which can be taken out to a front side in a state of opening a front cover of a main body. A transfer belt unit integrally constituted by a transfer belt, a drive roller, a driven roller, a transfer roller and the like is detachably set on the table unit. In the case of setting the transfer belt unit to the apparatus main body, the transfer belt unit is set on the table unit, the table unit is inserted into the apparatus main body, and the transfer belt unit is lifted up by rotating a handle so as to be brought into contact with the process unit. Accordingly, it is possible to easily attach and detach the transfer belt unit with respect to the apparatus main body, thereby simplifying a replacing operation.

Transfer belt unit

The compound lens is composed of a glass made lens that has a first curved surface portion and a synthetic resin made lens that has a second curved surface portion along the first curved surface portion of the glass made lens and is united in one body by press fitting this second curved surface portion to the first curved surface portion of the glass made lens.

Compound lens and optical system using compound lens

An optical scanner includes a light source to generate a light beam, a first optical unit to give a specified optical characteristic to the light beam emitted from the light source, a scanning unit including a rotatable member to scan a scanning object by applying the light beam passed through the first optical unit while rotating the rotatable member in a specified direction and a second optical unit to lead the light beam to form an image on a specified position of the scanning object; and a housing having a bottom portion to house the optical system, an opening portion provided at the side opposite to the bottom portion, a first reference surface that is used as a reference when the bottom side is set to a first external equipment and a second reference surface that is used as a reference when the opening side is set to a second external equipment.

Optical scanner, image forming apparatus and image forming apparatus

An optical unit includes a primary lens for converging a laser beam L emitted from a semiconductor laser element, a cylindrical lens for further converging the converged laser beam, and first and second plastic lenses having optical characteristics offsetting each other in at least one of first and second directions perpendicular to each other. By virtue of the primary lens and cylindrical lens, devices included in the optical deflector on the front side thereof can be made small, and also the arrangement of the lenses can be simplified. Devices of the same on the rear side thereof incorporate lenses including a planar surface, which reduces the required manufacturing cost.

Optical unit for use in laser beam printer apparatus

In an optical unit of the present invention, a laser element and a glass lens are contained in a lens barrel. The ray axis of the laser beam is aligned with the optical axis of the glass lens without accidental displacement. By surely fixing the lens barrel, shift of the lens along the optical axis or variation in distance between the lens and laser element can be prevented. In contrast, a manufacturing precision of a lens barrel holding member may be lowered and low-in-cost. In order to ensure exact fixing of the lens barrel, a leaf-spring and a bonding agent are used. In this case, it is desirable that the force per unit contact length exerted by the leaf-spring onto the lens barrel be in the range of 100&lt;F&lt;400 [gf/mm]. The amount of the bonding agent is determined so as to be sufficient for fixing the lens barrel and to prevent flowing-out of the bonding agent and an increase in time for drying.

Optical unit for use in an image forming apparatus

This invention relates to a device and a method for securing optical elements to a housing. The optical elements such as a tertiary lens, a fourth lens, a reflecting mirror, and a filter glass are received in the housing and bonded to the same by means of a visible ray hardening type bonding agent. A maximum bonding strength can be obtained by setting the bonding agent to have a thickness of 10-100 .mu.m and a hardness of 80 or less on the A-scale based on the Shore hardness test. Further, much time is not required for hardening the bonding agent.

Optical unit and method of fixing optical elements in optical unit

An optical deflector is employed in an optical unit incorporated in a laser beam printer. The optical deflector reflects a laser beam, which is generated by a laser diode toward a photosensitive body and is made to have a cross section of desirable size by a group of conversion lenses. The optical deflector is provided with reflecting surfaces whose cross sections are convex in a main scanning direction. The number of reflecting surfaces is defined by 4.times.m (m: a natural number), and therefore the optical deflector has four or eight reflecting surfaces, for instance. Since the number of reflecting surfaces is defined by 4.times.m, reflecting surfaces can be positioned easily and reliably with reference to the center of the shaft.

Optical deflector device for deflecting laser beam

In an optical unit used for a laser beam printer, a laser beam generated by a laser diode is converted by a group of conversion lenses into a laser beam having a predetermined-size cross section. The laser beam is directed toward a photosensitive body by a scanner. A focusing lens allows the rotating angle of the reflecting faces of the scanner to correspond to a desirable point on the surface of the photosensitive body. In other words, the rotating angle is made to correspond to the distance between the optical axis center determined with respect to a main scanning direction and a point to which the laser beam is irradiated for scanning. The conversion lenses includes at least one aspheric glass lens arranged close to the laser diode. The glass lens and the laser diode are integrally held by a lens barrel which linearly expands in a predetermined manner in response to a temperature change. Since the distance between the glass lens and the laser diode is constantly equal in accordance with the temperature change, the laser beam is constantly allowed to have a cross section of desirable size, without reference to the temperature change.

Optical unit for use in laser beam printer or the like with temperature

In an optical unit used for a laser beam printer, a laser beam generated by a laser diode is converted by a group of conversion lenses into a laser beam having a predetermined-size cross section. The laser beam is directed toward a photosensitive body by a scanner, so as to scan the photosensitive body at a constant speed. A focusing lens allows the rotating angle of the reflecting faces of the scAnner to correspond to a desirable point on the surface of the photosensitive body. In other words, the rotating angle is made to correspond to the distance between the optical axis center determined with respect to a main scanning direction and a point to which the laser beam is irradiated for scanning. The focusing lens is arranged between the scanner and the photosensitive body and shapes the laser beam reflected by the scanner such that the laser beam has a desirable diameter. The focusing lens has a toric surface which is formed on the side closer to the scanner than the other and which is rotation-symmetric with reference to an axis extending in the main scanning direction. The cross sectional shape of the focusing lens is concave in a plane expanding in the main scanning direction and is convex in a plane expanding in a sub-scanning direction.

Optical unit for use in laser beam printer or the like

In a light deflecting apparatus having a motor shaft rotatable at high speed, bearings have a suitable simple construction such that the whole apparatus can be reduced in size and weight.

Light deflecting apparatus

In an optical unit incorporated in a laser beam printer, a laser beam generated by a laser diode is converted by a group of conversion lenses into a laser beam having a predetermined-size cross section. The laser beam is directed toward a photosensitive body by a scanner unit, so as to scan the photosensitive body. A focusing lens allows the rotataing angle of the reflecting faces of the scanner unit to correspond to a desirable point on the surface of the photosensitive body. In other words, the rotating angle is made to correspond to the distance between the optical axis center determined with respect to a main scanning direction and a point to which the laser beam is irradiated for scanning. The conversion lenses include at least one aspheric glass lens. The conversion lenses further includes a pair of plastic lenses which have substantially the same power and opposite polarities with respect to either the main scanning direction or a subscanning direction. Among the lenses mentioned above, that lens which is located closest to the glass lens is integral with the laser diode. The focusing lens is formed of a material having substantially equivalent characteristics to those of the paired plastic lenses.

An optical deflector is employed in an optical unit incorporated in a laser beam printer. The optical deflector reflects a laser beam, which is emitted by a laser diode and is made to have a cross section of desirable size by a group of conversion lenses, toward a photosensitive body. The optical deflector contains a polygonal mirror having four or eight reflecting surfaces. Each of these reflecting surfaces has a cross section which is convex in a main scanning direction. The polygonal mirror is adhered to the shaft of a motor used for rotating the polygonal mirror. Alternatively, it is adhered to the base member fixed to the shaft.

In an optical unit incorporated in a laser beam printer, a laser beam generated by a laser diode is converted by a group of conversion lenses into a laser beam having a predetermined-size cross section. The laser beam is directed toward a photosensitive body by a scanner unit, so as to scan the photosensitive body. A focusing lens allows the rotating angle of the reflecting faces of the scanner unit to correspond to a desirable point on the surface of the photosensitive body. In other words, the rotating angle is made to correspond to the distance between the optical axis center determined with respect to a main scanning direction and a point to which the laser beam is irradiated for scanning. Each of the reflecting faces is convex. The focusing lens is constituted by an aspheric-surface plastic lens having a toric surface which is rotation-symmetric with reference to an axis extending in the main scanning direction. The rotating speed of the convex mirrors of the scanner unit is determined in accordance with the characteristics of the focusing lens. Therefore, both the field curve and the f.theta. characteristic can be corrected.

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Tokyo, Japan

Ken Omura