Abstract: 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<F<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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.