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: 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 .

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 .

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 deflector, a method of producing the optical deflector, an optical scanning device, and an image forming apparatus are disclosed that are able to save resources, provide high reliability at low cost, and enable stacked and relatively-offset polygon mirrors to be arranged precisely. The optical deflector includes a rotary member supported by a bearing with plural polygon mirrors fixed thereon. The polygon mirrors are stacked along a rotation axis of the rotary member, the polygon mirrors are relatively offset by a predetermined angle in a rotation plane of the rotary member, and an effective deflection area of each of the reflection surfaces of any one of the polygon mirrors is positioned away from a center of the corresponding reflection surfaces of the other one of the polygon mirrors in the direction of the rotation axis.

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: 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 to 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: An optical deflector, a method of producing the optical deflector, an optical scanning device, and an image forming apparatus are disclosed that are able to save resources, provide high reliability at low cost, and enable stacked and relatively-offset polygon mirrors to be arranged precisely. The optical deflector includes a rotary member supported by a bearing with plural polygon mirrors fixed thereon. The polygon mirrors are stacked along a rotation axis of the rotary member, the polygon mirrors are relatively offset by a predetermined angle in a rotation plane of the rotary member, and an effective deflection area of each of the reflection surfaces of any one of the polygon mirrors is positioned away from a center of the corresponding reflection surfaces of the other one of the polygon mirrors in the direction of the rotation axis.

Abstract: An induction heating type fixing device for an electrophotographic image forming apparatus is disclosed. An inducting heating coil has a plurality of bobbins each having a particular diameter and assembled in a telescopic manner. A particular conductor is wound round each bobbin beforehand with leads being laid inside of the conductor. The bobbin may be implemented as a plurality of bobbin members removably connected together.

Abstract: An induction heating type fixing device for an electrophotographic image forming apparatus is disclosed. An inducting heating coil has a plurality of bobbins each having a particular diameter and assembled in a telescopic manner. A particular conductor is wound round each bobbin beforehand with leads being laid inside of the conductor. The bobbin may be implemented as a plurality of bobbin members removably connected together.

Abstract: An induction heating type fixing device for an electrophotographic image forming apparatus is disclosed. An inducting heating coil has a plurality of bobbins each having a particular diameter and assembled in a telescopic manner. A particular conductor is wound round each bobbin beforehand with leads being laid inside of the conductor. The bobbin may be implemented as a plurality of bobbin members removably connected together.

Abstract: An induction heating type fixing device for an electrophotographic image forming apparatus is disclosed. An inducting heating coil has a plurality of bobbins each having a particular diameter and assembled in a telescopic manner. A particular conductor is wound round each bobbin beforehand with leads being laid inside of the conductor. The bobbin may be implemented as a plurality of bobbin members removably connected together.

Abstract: An induction heating type fixing device for an electrophotographic image forming apparatus is disclosed. An inducting heating coil has a plurality of bobbins each having a particular diameter and assembled in a telescopic manner. A particular conductor is wound round each bobbin beforehand with leads being laid inside of the conductor. The bobbin may be implemented as a plurality of bobbin members removably connected together.

Abstract: An induction heating type fixing device for an electrophotographic image forming apparatus is disclosed. An inducting heating coil has a plurality of bobbins each having a particular diameter and assembled in a telescopic manner. A particular conductor is wound round each bobbin beforehand with leads being laid inside of the conductor. The bobbin may be implemented as a plurality of bobbin members removably connected together.

Abstract: A fixing device using induction heating for an electrophotographic image forming apparatus includes a heat roller and a press roller for fixing a toner image on a recording medium while conveying the recording medium. A coil unit is located outside of the heat roller and upstream of a nip between the heat roller and the press roller in the direction of rotation of the heat roller for generating an induced magnetic flux. The coil unit concentratedly heats the heat roller and thereby efficiently feeds heat to the recording medium.

Abstract: An induction heating type fixing device for an electrophotographic printer, facsimile apparatus, copier or similar image forming apparatus and an induced current generating member therefore are disclosed. A coil is wound round a bobbin applied with an adhesion preventing material. After the coil has been adhered by nonconductive adhesive by impregnation, the coil and bobbin subassembly is inserted into a hollow cylinder body formed of a heat-resistant insulating material. After the coil has been adhered to the cylindrical body, the bobbin is pulled out to produce the induced current generating member.