An optical scanning device includes a polygon mirror, a motor driving the polygon mirror, a substrate on which the polygon mirror and the motor are mounted, and a connector mounted on the substrate using a surface mount technology. The connector is provided with a plurality of terminal pins including vertical portions extending substantially in a vertical direction with respect to a plane of the substrate and bonding portions bonded to a surface of the substrate by solder. In the plurality of terminal pins, each of leading ends of the bonding portions faces in a same first direction. In a state in which a cable which sends an electric power and an electric signal to the motor is connected to the connector, the cable is connected to the connector so as to extend in a second direction opposite to the first direction.

A motor that rotates a rotation shaft of a polygon mirror is mounted on a motor board. A first photoelectric conversion element senses beam light reflected by each of a plurality of mirror surfaces. A sensing target portion is provided to the rotation shaft. A light sensor is disposed apart from the motor board and includes a light emitting portion and a second photoelectric conversion element. An amplification circuit amplifies a sense signal of the second photoelectric conversion element. A control device controls a timing of starting to form an electrostatic latent image on the basis of a sense signal of the first photoelectric conversion element. The control device identifies a scanning surface that is scanning the beam light on the basis of the sense signal of the second photoelectric conversion element amplified by the amplification circuit, and adjusts a pixel pitch of the electrostatic latent image.

An optical scanning apparatus is disclosed that includes a light source, a deflector including a rotatable polygonal mirror configured to deflect laser light emitted from the light source, a lens configured to focus the deflected laser light, and an optical box configured to contain the deflector and the lens, with the optical box including a plurality of reference surfaces serving as an attaching surface to an image forming apparatus, and a plurality of planes arranged behind the plurality of reference surfaces along an axis of rotation of the rotatable polygonal mirror, and the axis of the rotation being parallel to the plurality of reference surfaces.

An optical scanner includes: deflector deflecting a beam from a light source to scan scanned surface in main-scanning direction; and a first element closest to scanned surface and guides the beam to scanned surface, in which thickness of first element in optical-axis direction in main-scanning section changes in main-scanning direction, first element includes an optical surface whose normal on main-scanning section is tilted thereto, the normal tilt amount changes in main-scanning direction, and a position in main-scanning direction where interval in optical-axis direction between both ends in sub-scanning direction of effective region of the optical surface in sub-scanning section is maximum, a position in main-scanning direction where a thickness in optical-axis direction of first element in main-scanning section is maximum, and maximum image height in main-scanning direction on scanned surface are appropriately set in region on one side of the optical surface relative to optical axis in main-scanning direction.

A cover covers the periphery of a polygon mirror and a motor, and has a detection aperture formed at a specific position around a portion of a rotation shaft where a to-be-detected portion is formed. An reflective optical sensor is disposed outside the cover so as to face the detection aperture. The detection aperture is formed in an area where internally reflected light, which is the beam light reflected toward the inner surface of the cover on each of the plurality of mirror surfaces, can reach after at least two specular reflections on the inner surface of the cover when viewed in an axial direction along the rotation shaft.

A light scanning apparatus according to the present disclosure includes a deflecting unit deflecting a light flux from a light source to scan a surface in a main scanning direction, a first optical system guiding the light flux deflected by the deflecting unit to the surface to be scanned at a first timing, and a second optical system guiding the light flux deflected by the deflecting unit to a light receiving element at a second timing different from the first timing, in which the second optical system includes a first optical element which has a diffracting surface and condenses the light flux deflected by the deflecting unit at the second timing in a main scanning cross section, and a value of a diffractive power of the first optical element is equal to or larger than a value of a refractive power thereof in the main scanning cross section.

In order to provide a polygon mirror which can reduce a light amount difference among respective image heights on a scanned surface with suppressing an increase in size in a light scanning apparatus, the polygon mirror according to the present invention includes a plurality of rectangular reflecting surfaces in which the following condition is satisfied:
0.02<|1B/A|<0.10 where A represents a reflectivity at a center of the reflecting surface with respect to a light flux which is incident at a predetermined incident angle, and B represents the reflectivity at a predetermined point between the center and an end in the longitudinal direction of the reflecting surface with respect to the light flux which is incident at the predetermined incident angle.

A cover closes a first opening of a main box portion. A second opening is formed in a unit housing of an optical scanning unit to externally expose a connector mounted on an electronic board. The unit housing has a protruding inner frame portion and a wiring portion. The protruding inner frame portion protrudes from an outer surface of the unit housing and surrounds the second opening. The cover includes a protruding outer frame portion that protrudes from an inner surface of the cover and surrounds the protruding inner frame portion. A top portion of the protruding inner frame portion is formed along an inner-side portion of the protruding outer frame portion on an inner surface of the cover. A top portion of the protruding outer frame portion is formed along an outer-side portion of the protruding inner frame portion on the outer surface of the unit housing.

A light scanning apparatus satisfies the following conditions: 0.60(dY.sub.max/d)/(dY.sub.0/d)0.98; and 0.50<Sk/ft<1.00, where, when a deflecting unit rotates at a constant angular velocity, represents a scanning angle between a principal ray of a light flux immediately after deflected by the deflecting unit and an optical axis of an imaging optical system, Y.sub.0 represents an on-axis image height, Y.sub.max represents a first outermost off-axis image height on a side opposite to a light source with respect to the optical axis of the imaging optical system in a main scanning cross section, ft represents a focal distance of the imaging optical system in the main scanning cross section, and Sk represents a distance between a rear-side principal plane of the imaging optical system and a scanned surface on an optical path of a principal ray of the light flux that travels to the on-axis image height.

An optical scanning device includes a light source unit, a polygonal mirror, a scanning lens, a casing, and a temperature sensor. The light source unit is configured to emit a laser beam. The polygonal mirror is configured to reflect the emitted laser beam from the light source unit by being rotated about a rotation axis extending in an upper-and-lower direction, whereby a peripheral surface of an image bearing member is scanned in a main scanning direction. The scanning lens is configured to form the laser beam reflected by the polygonal mirror into an image on the peripheral surface of the image bearing member. The casing is configured to house the light source unit, the polygonal mirror, and the scanning lens. The temperature sensor is configured to detect a temperature in the casing. The temperature sensor is configured to detect a temperature of the developing device.