Abstract: An optical scanning device includes: a light source device that emits five light beams corresponding to four basic colors and a single specific color; and five scanning optical systems corresponding the five light beams. One light beam in a first waveband among the light beams corresponding to the four basic colors enters one scanning optical system of the five scanning optical systems. The one scanning optical system includes a dichroic mirror that transmits a light beam in a second waveband different from the first waveband. An angle ?b formed between a normal to the incidence plane of the dichroic mirror and orthogonal projection to an assumed plane orthogonal to the main scanning corresponding direction of the incident path of the light beam to the incidence plane of the dichroic mirror is set at an angle of 0° or more and an angle of 45° or less.

Abstract: An optical scanning device includes: a light source unit; a light deflecting unit that deflects a light beam emitted from the light source unit; a scanning optical device that focuses the light beam deflected by the light deflecting unit on a scanned surface; and a light shielding member. The scanning optical device is provided in a direction in which a sound pressure level of a noise caused by rotation of a rotating polygon mirror included in the light deflecting unit is highest.

Abstract: An optical deflector including a rotary member supported by a bearing shaft and rotatively driven by a motor for deflecting a plurality of laser beams separated from each other in a rotational axis direction of the rotary member is disclosed. The optical deflector includes a polygon mirror having four sides arranged about the rotational axis direction. Each of the four sides is a continuous plane having a plurality of effective reflection areas separated from each other in the rotational axis direction.

Abstract: An optical deflector including a rotary member supported by a bearing shaft and rotatively driven by a motor for deflecting a plurality of laser beams separated from each other in a rotational axis direction of the rotary member is disclosed. The optical deflector includes a polygon mirror having four sides arranged about the rotational axis direction. Each of the four sides is a continuous plane having a plurality of effective reflection areas separated from each other in the rotational axis direction.

Abstract: An optical scanning apparatus includes a light source; and a rotational polygon mirror having N reflecting surfaces, the rotational polygon mirror being configured to reflect a light flux emitted from the light source so that a scanning surface is scanned along a main-scanning direction with reflected from the rotational polygon mirror. A width of the light flux incident on the rotational polygon mirror in a direction corresponding to the main-scanning direction is smaller than a width of each reflecting surface of the rotational polygon mirror in the direction corresponding to the main-scanning direction.

Abstract: An optical deflector including a rotary member supported by a bearing shaft and rotatively driven by a motor for deflecting a plurality of laser beams separated from each other in a rotational axis direction of the rotary member is disclosed. The optical deflector includes a polygon mirror having four sides arranged about the rotational axis direction. Each of the four sides is a continuous plane having a plurality of effective reflection areas separated from each other in the rotational axis direction.

Abstract: An optical scanning unit includes a rotatable multi-faceted mirror having a plurality of faces reflecting light flux emitted from a light source to scan a scanning area in a main scanning direction. A width of the light flux striking the rotatable multi-faceted mirror is smaller than a length of a face of the rotatable multi-faceted mirror. The entire of light flux striking the rotatable multi-faceted mirror is reflected at a first face when the light flux reflected by the rotatable multi-faceted mirror is directed to the center portion of the scanning area. A part of the light flux striking the rotatable multi-faceted mirror is reflected at the first face while the remaining of the light flux is reflected at a second face when the light flux reflected by the rotatable multi-faceted mirror is directed to a least one of the two end portions of the scanning area.

Abstract: An optical scanning device includes a plurality of scanning optical systems that focus light beams deflected by an optical deflector onto corresponding scanning surfaces. The systems include a first scanning optical system and a second scanning optical system. The first scanning optical system and the second scanning optical system are disposed respectively at each side of a plane including a rotation axis of a polygonal-mirror optical deflector. Each of the scanning optical systems includes a synchronous detection optical system that determines a timing to start scanning the scanning surfaces with the light beams. When a time from the end of an effective scanning area in the second scanning optical system to synchronous detection in the first scanning optical system is Ta, and a time from the end of an effective scanning area in the first scanning optical system to synchronous detection in the second scanning optical system is Tb, Ta>Tb.

Abstract: An optical scanning device includes: a light source device that emits five light beams corresponding to four basic colors and a single specific color; and five scanning optical systems corresponding the five light beams. One light beam in a first waveband among the light beams corresponding to the four basic colors enters one scanning optical system of the five scanning optical systems. The one scanning optical system includes a dichroic mirror that transmits a light beam in a second waveband different from the first waveband. An angle ?b formed between a normal to the incidence plane of the dichroic mirror and orthogonal projection to an assumed plane orthogonal to the main scanning corresponding direction of the incident path of the light beam to the incidence plane of the dichroic mirror is set at an angle of 0° or more and an angle of 45° or less.

Abstract: An optical deflector including a rotary member supported by a bearing shaft and rotatively driven by a motor for deflecting a plurality of laser beams separated from each other in a rotational axis direction of the rotary member is disclosed. The optical deflector includes a polygon mirror having four sides arranged about the rotational axis direction. Each of the four sides is a continuous plane having a plurality of effective reflection areas separated from each other in the rotational axis direction.

Abstract: An optical deflector including a rotary member supported by a bearing shaft and rotatively driven by a motor for deflecting a plurality of laser beams separated from each other in a rotational axis direction of the rotary member is disclosed. The optical deflector includes a polygon mirror having four sides arranged about the rotational axis direction. Each of the four sides is a continuous plane having a plurality of effective reflection areas separated from each other in the rotational axis direction.

Abstract: An optical scanning device includes: a light source unit; a light deflecting unit that deflects a light beam emitted from the light source unit; a scanning optical device that focuses the light beam deflected by the light deflecting unit on a scanned surface; and a light shielding member. The scanning optical device is provided in a direction in which a sound pressure level of a noise caused by rotation of a rotating polygon mirror included in the light deflecting unit is highest.

Abstract: An optical scanning device includes an optical housing in which a polygon mirror that is rotated by a motor is accommodated and an air inlet that includes a filter. An airflow guiding member is arranged at a position opposite to a surface of the polygon mirror on the air inlet side. An air inducing path is provided, which includes a first flowing path and a second flowing path. The first flowing path includes a first end linked to the air inlet and a second end arranged close to a mirror surface of the polygon mirror. The second flowing path is formed with a surface of the airflow guiding member on an opposite side of the air inlet and a top surface of the polygon mirror.

Abstract: Provided is an optical scanning device including: a plurality of light sources; an optical deflector that includes reflection surfaces that deflect different light beams toward opposite sides of the optical deflector; and a light-shielding member provided in an area between incident light beams emitted from the plurality of light sources. The light-shielding member is positioned such that a portion of the light-shielding member is in a light-shield area surrounded by a circumscribed circle of the optical deflector, a line tangent to the circumscribed circle and orthogonal to a Y direction, and the incident light beam, the Y direction being a direction parallel to a main scanning direction and passing through a rotation center of the optical deflector, the main scanning direction being a direction, in which surfaces of image carriers are scanned.

Abstract: In the optical deflector, the mean width of profile elements of a cross section of the deflection surface in the sub scan direction is set to be less than the spacing between spots of the light beams formed in the sub scan direction of the deflection surface. This makes it possible to prevent a variation in the size and shape of the spots of the light beams deflected by the deflection surface due to the undulation (unevenness) of the deflection surface. As a result, it is able to suppress a decrease of the granularity of images and form images with high quality.

Abstract: A hydrodynamic bearing unit using oil includes a shaft to be driven, a bearing member configured to support the shaft in a non-contact manner through a bearing gap by a hydrodynamic pressure of the oil, which is generated in the bearing gap while the shaft relatively rotate with respect to the bearing member, a housing configured to house the bearing member and having an opening at one end thereof, another end thereof being enclosed, a sealing member configured to seal a part of the opening of the housing, a channel configured to communicate a space formed between the shaft, the bearing member and the housing with an outside air, and a pressing member configured to press and fix the bearing member on the housing. At least one open part configured to release an air bubble contained in the housing is provided between the bearing member and the sealing member.

Abstract: An optical scanning device includes an optical housing in which a polygon mirror that is rotated by a motor is accommodated and an air inlet that includes a filter. An airflow guiding member is arranged at a position opposite to a surface of the polygon mirror on the air inlet side. An air inducing path is provided, which includes a first flowing path and a second flowing path. The first flowing path includes a first end linked to the air inlet and a second end arranged close to a mirror surface of the polygon mirror. The second flowing path is formed with a surface of the airflow guiding member on an opposite side of the air inlet and a top surface of the polygon mirror.

Abstract: An optical deflector is disclosed that includes a rotary shaft; plural rotary polygon mirrors laminated in an axis direction of the rotary shaft, the rotary polygon mirrors having reflection surfaces and the reflection surfaces of one rotary polygon mirror and those of another rotary polygon mirror facing in different directions; and a joining section provided between the rotary polygon mirrors. In the optical deflector, the joining section is integrally formed with at least one of the rotary polygon mirrors.

Abstract: A rotary drive apparatus includes a rotary body with a support portion, a rotor magnet supported by the support portion of the rotary body, a fixation section facing the rotor magnet and rotatably supporting the rotary body, and a winding coil provided in the fixation section, in which an expression E1/E2?0.75 is satisfied where Young's modulus of the rotor magnet is E1 [GPa], and Young's modulus of the support portion is E2 [GPa].

Abstract: An optical deflector includes a rotary body including a polygon mirror; a rotation shaft fixed to the rotary body; a bearing unit rotatably supporting the rotation shaft; and a board to which the bearing unit is fixed. Where P [rpm] is the number of revolutions of the rotary body, l [m] is a distance between a center of gravity of the rotary body and the board, m [kg] is mass of the rotary body, r [m] is a radius of the rotation shaft, E [Pa] is Young's modulus of the rotation shaft, and t [mm] is a thickness of the board, the following inequalities are satisfied: 1 2 ? ? ? ? ? 3 ? ? ? ? Er 4 4 ? ? ml 3 ? 2 × P 60 ? ? and ? ? 0.8 ? t ? 1.8 .