Abstract: In the production of a non-oriented electrical steel sheet by subjecting a steel slab having a certain component composition to a hot rolling, a hot-band annealing, a cold rolling and a finish annealing, the conditions of the finish annealing are controlled such that a yield stress of the steel sheet after the finish annealing is not less than 480 MPa. Also, when a motor core is produced by using the above steel sheet, there can be provided a non-oriented electrical steel sheet capable of producing a rotor core and a stator core as the same raw material where the stator core is subjected to a stress relief annealing at a soaking temperature of 780 to 950° C. in an atmosphere having a nitrogen content of not more than 30 vol % and a dew point of not higher than ?20° C., while a motor core is produced with such a steel sheet.

Abstract: A rotatable polygon mirror includes a plurality of reflecting surfaces provided in parallel to a rotational axis direction, first surface and second surface of polygonal shape perpendicular to the plurality of reflecting surface and of which each side is continued to the plurality of reflecting surfaces. The second surface is opposite to the first surface. A through hole penetrates though the first and second surfaces in parallel to the rotational axis direction and to engage with a rotational shaft of a driving portion. As seen in the rotational axis direction, the through hole has substantially similar shape to the polygonal shape of the first and the second surfaces, and vertexes of the similar shape of the through hole are different in phase from apexes of the polygonal shape of the first and second surfaces with respect to a rotational direction of the polygon mirror.

Abstract: A rotatable polygon mirror molded with a resin includes a plurality of reflecting surfaces provided in parallel to a rotational axis direction, a surface perpendicular to the rotational axis direction; a plurality of gate portions provided on the surface and a recess-projection on the surface. The recess-projection has at least one shape of a recess shape recessed in the rotational axis from the and a projection shape projected from the surface as viewed in a direction perpendicular to the rotational axis direction. The recess-projection is provided in a virtual straight line with equal distances from two of the adjacent gate portions with respect to a rotational direction of the rotatable polygon mirror and connecting a rotation center of the rotatable polygon mirror and a boundary of two of the adjacent reflecting surfaces with respect to the rotational direction.

Abstract: An optical deflector includes a rotatable polygon mirror and an urging member to urge the rotatable polygon mirror toward a driving unit to fix the rotatable polygon mirror to the driving unit. The urging member includes an annular shape portion having an annular shape surface contacting the rotatable polygon mirror and a plurality of arm portions integrally formed with the annular shape portion. The plurality of the arm portions radially extend from an outer circumference of the annular shape portion, are disposed at equal intervals with respect to a rotational direction with a rotation center of the rotatable polygon mirror, and are pressed by a restricting member.

Abstract: An image forming apparatus includes a photosensitive member and a scanning unit including a light source, a rotatable polygonal mirror, and a sensor. The image forming apparatus includes setting of an operation in a first mode and setting of an operation in a second mode. The image forming apparatus further comprises, a surface identifying portion and a correction data storing portion configured to prestore correction data including first correction data for a first rotational speed and second correction data for a second rotational speed. Positional deviation in a main scan direction of laser light is corrected on the basis of the first correction data or the second correction data.

Abstract: An image forming apparatus to form an image on a recording material includes a photosensitive member, an exposure device to form a latent image on the photosensitive member, a tubular body defining a space in which at least a part of the exposure device is contained, and a support portion that supports the exposure device and is provided along a rotation axis direction of the photosensitive member in the space of the tubular body. The image forming apparatus further includes, in the rotation axis direction, a first side plate fixed to one end portion of the tubular body, and a second side plate fixed to another end portion of the tubular body. One support portion end portion in the rotation axis direction is fixed to the first side plate, and another support portion end portion in the rotation axis direction is fixed to the second side plate.

Abstract: An image forming apparatus includes a photosensitive member and a scanning unit including a light source, a rotatable polygonal mirror, and a sensor. The image forming apparatus includes setting of an operation in a first mode and setting of an operation in a second mode. The image forming apparatus further comprises, a surface identifying portion and a correction data storing portion configured to prestore correction data including first correction data for a first rotational speed and second correction data for a second rotational speed. Positional deviation in a main scan direction of laser light is corrected on the basis of the first correction data or the second correction data.

Abstract: In an image forming apparatus, a lifetime detection unit acquires an activation time threshold using a threshold stored in an activation time storage unit and an environmental temperature detected by a temperature detection unit, and, in a case where activation time acquired by an activation time acquisition unit is shorter than the activation time threshold, makes a notification of at least one of a lifetime or replacement of a deflection unit or an optical scanning unit.

Abstract: A light deflector includes a rotary polygon mirror and a motor to rotate the rotary polygon mirror. The rotary polygon mirror includes reflecting surfaces to reflect light emitted from a light source and a hole portion provided in a rotational axis direction. The motor includes a shaft portion in the hole portion and a support member supporting the rotary polygon mirror. The support member is fixed to, and coaxial with, the shaft portion, and includes an insertion portion in the hole portion. The rotary polygon mirror includes a protruded portion near the hole portion and protruding from at least one reflecting surface orthogonal to the rotational axis direction. The protruded portion includes a fitting portion fitted to the shaft portion or the support member and in which a portion continued from a hole portion surface is protruded toward the rotation center more than the surface forming the hole portion.

Abstract: In an image forming apparatus, a lifetime detection unit acquires an activation time threshold using a threshold stored in an activation time storage unit and an environmental temperature detected by a temperature detection unit, and, in a case where activation time acquired by an activation time acquisition unit is shorter than the activation time threshold, makes a notification of at least one of a lifetime or replacement of a deflection unit or an optical scanning unit.

Abstract: An image forming apparatus to form an image on a recording material includes a photosensitive member, an exposure device to form a latent image on the photosensitive member, a tubular body defining a space in which at least a part of the exposure device is contained, and a support portion that supports the exposure device and is provided along a rotation axis direction of the photosensitive member in the space of the tubular body. The image forming apparatus further includes, in the rotation axis direction, a first side plate fixed to one end portion of the tubular body, and a second side plate fixed to another end portion of the tubular body. One support portion end portion in the rotation axis direction is fixed to the first side plate, and another support portion end portion in the rotation axis direction is fixed to the second side plate.

Abstract: In an optical scanning device, an outer wall closest to a circumscribed circle of a rotating polygon mirror has a space in a position facing to a position of a reflection surface of the rotating polygon mirror in an axial direction of a rotating shaft. A part of a cover is provided in a position farther from the circumscribed circle than the outer wall so as to close the space, when the optical scanning device is viewed in a direction perpendicular to the axial direction of the rotating shaft.

Abstract: A manufacturing method of a polygonal mirror using a metal mold including a first mold, a second mold, a third mold, and a fourth mold includes a step of forming the molded member by providing the third mold and the fourth mold between the first mold and the second mold in a state in which the third mold and the fourth mold are in contact with each other and then by injecting a resin material into the metal mold, and a step of separating the third mold from the first crossing surface of the molded member in a direction crossing the first crossing surface.

Abstract: A polygonal mirror includes reflecting surfaces, a molded member including a first surface and a second surface, a contact portion, and gate marks. Each of said first surface and said second surface has a polygonal shape. The contact portion and the gate marks are formed at non-overlapping positions with a line segment connecting a vertex of the polygonal shape with a rotation center. The gate marks and the reflecting surfaces are the same in number. A perpendicular bisector of a line segment connecting centers of the gate marks adjacent to each other with respect to a rotational direction of the polygonal mirror is formed at a position passing through an associated vertex of the polygonal shape and the rotation center.

Abstract: An image forming apparatus to form an image on a recording material includes a photosensitive member, an exposure device to form a latent image on the photosensitive member, a tubular body defining a space in which at least a part of the exposure device is contained, and a support portion that supports the exposure device and is provided along a rotation axis direction of the photosensitive member in the space of the tubular body. The image forming apparatus further includes, in the rotation axis direction, a first side plate fixed to one end portion of the tubular body, and a second side plate fixed to another end portion of the tubular body. One support portion end portion in the rotation axis direction is fixed to the first side plate, and another support portion end portion in the rotation axis direction is fixed to the second side plate.

Abstract: A light deflector includes a rotary polygon mirror and a motor to rotate the rotary polygon mirror. The rotary polygon mirror includes reflecting surfaces to reflect light emitted from a light source and a hole portion provided in a rotational axis direction. The motor includes a shaft portion in the hole portion and a support member supporting the rotary polygon mirror. The support member is fixed to, and coaxial with, the shaft portion, and includes an insertion portion in the hole portion. The rotary polygon mirror includes a protruded portion near the hole portion and protruding from at least one reflecting surface orthogonal to the rotational axis direction. The protruded portion includes a fitting portion fitted to the shaft portion or the support member and in which a portion continued from a hole portion surface is protruded toward the rotation center more than the surface forming the hole portion.

Abstract: A rotary polygon mirror has no recess in a thickness region of one of the reflecting surfaces of the rotary polygon mirror in the direction of the rotation axis of the rotary polygon mirror and has a protruding portion protruding from the thickness region in a direction away from the thickness region.

Abstract: An image forming apparatus to form an image on a recording material includes a photosensitive member, an exposure device to form a latent image on the photosensitive member, a tubular body defining a space in which at least a part of the exposure device is contained, and a support portion that supports the exposure device and is provided along a rotation axis direction of the photosensitive member in the space of the tubular body. The image forming apparatus further includes, in the rotation axis direction, a first side plate fixed to one end portion of the tubular body, and a second side plate fixed to another end portion of the tubular body. One support portion end portion in the rotation axis direction is fixed to the first side plate, and another support portion end portion in the rotation axis direction is fixed to the second side plate.

Abstract: An image forming apparatus for forming an image on a recording material includes a photosensitive member; an optical scanning unit including a light source, an optical box, and a cover; and a fan. The fan is provided so that air from the fan directly impinges on the cover of the optical scanning unit. As seen in a direction perpendicular to a rotational axis of the rotatable polygonal mirror, a rib extending from a top plate of the cover toward an optical box side is provided at a portion of the cover in the neighborhood of a light beam emitting port of the optical scanning unit. The cover is provided with an extended portion extended from the rib in a light beam emitting direction.

Abstract: An image forming apparatus to form an image on a recording material includes a photosensitive member, an exposure device to form a latent image on the photosensitive member, a tubular body defining a space in which at least a part of the exposure device is contained, and a support portion that supports the exposure device and is provided along a rotation axis direction of the photosensitive member in the space of the tubular body. The image forming apparatus further includes, in the rotation axis direction, a first side plate fixed to one end portion of the tubular body, and a second side plate fixed to another end portion of the tubular body. One support portion end portion in the rotation axis direction is fixed to the first side plate, and another support portion end portion in the rotation axis direction is fixed to the second side plate.