An image forming apparatus includes a casing, an image forming unit, a plurality of covers, a shutter, and a linkage mechanism. The image forming unit includes a light source and is disposed in an interior of the casing. The image forming unit forms an image on a recording medium. The covers are openable and closable relative to the casing. The shutter is openable and closable relative to the light source. The linkage mechanism links the respective covers to the shutter. The linkage mechanism sets the shutter in a closed state in a situation in which at least one of the covers is in an open state and sets the shutter in an open state in a situation in which all the covers are in a closed state.

An exposure device capable of precisely focusing light on a scanned surface to accomplish a good image quality is provided. The exposure device includes a substrate on which a plurality of light sources are arranged along a main-scanning direction, a lens array including a plurality of lenses configured to focus light emitted by the plurality of light sources on a scanned surface, and a housing configured to support the substrate and the lens array such that a certain spacing is maintained between the plurality of light sources and the plurality of lenses. At least a portion of the substrate is spaced apart from the housing along a sub-scanning direction.

An image forming apparatus capable of correcting relative position in exposure position between laser beams that scan a photosensitive drum in a scanning direction of the laser beams. A semiconductor laser includes first and second light emitting elements for emitting first and second laser beams. These elements are arranged such that the laser beams expose positions on the photosensitive drum different in the sub scanning direction. A polygon mirror deflects the laser beams to scan the photosensitive drum. Relative position in the scanning direction between images to be formed on the photosensitive drum by exposure by the first and second laser beams is corrected based on correction data. An image data generation section generates drive signals associated with the respective light emitting elements. A semiconductor laser drive circuit causes the semiconductor laser to emit the first and second laser beams, based on the drive signals.

A light scanning apparatus, including: a light source; a deflector having a rotary polygon mirror configured to deflect the light beam emitted from the light source, and a motor configured to rotate the polygon mirror; a plurality of reflecting mirrors configured to reflect the light beam to the photosensitive member; and an optical box on which the light source is mounted, wherein the optical box has an installation wall on which the deflector is installed and a support wall positioned on a side of the photosensitive member with respect to the polygon mirror, the support wall being provided with a support portion configured to support at least one reflecting mirror, a stepped portion having a plurality of steps is formed between the installation wall and the support wall, and a back surface of the stepped portion has a shape following an inside surface of the stepped portion.

A light scanning apparatus, including: a light source configured to emit a light beam; and a rotary polygon mirror configured to deflect the light beam emitted from the light source so that the light beam scans a surface of a photosensitive member, wherein the rotary polygon mirror is formed in a four-sided polygon, and wherein a difference between a pair of diametrically opposed interior angles of the rotary polygon mirror is larger than 0.03°, and a difference between another pair of diametrically opposed interior angles of the rotary polygon mirror is 0.03° or less.

A lens unit includes a first lens array including first lenses arranged in at least two lines; a second lens array including second lenses arranged in an arrangement relationship corresponding to the first lens array, the second lenses respectively facing the first lenses, the second lens array being arranged to face the first lens array so that each pair of the first and second lenses has a common optical axis; and a first light blocking member arranged between the first lens array and the second lens array and having first openings each being arranged to face the pair of the first and second lenses in a direction of the optical axis. An interval PXL from an array center position between two adjacent lines to the optical axis and an interval PXS from the array center position to an opening center of the first opening satisfy PXL<PXS.

A holding member includes a first opposing portion (first inner wall surface) and a second opposing portion (second inner wall surface) which oppose side wall surfaces of a lens array. Side wall surfaces of the lens array on opposite end sides with respect to a longitudinal direction of the lens array are exposed from opposite ends of the first opposing portion and opposite ends of the second opposing portion.

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.

According to at least one embodiment, a lens mirror array includes a plurality of optical elements. An optical element of the plurality of optical elements includes an incident surface on which light is incident, an emitting surface configured to emit the light incident through the incident surface, at least one reflecting surface reflecting the light incident through the incident surface toward the emitting surface, and a light shielding portion configured to block the light. The incident surface includes an effective surface configured to pass effective light emitted from the emitting surface and a directional surface configured to direct unnecessary light to the light shielding portion.

An image forming apparatus, including a photosensitive member, a scanning optical unit configured to scan the photosensitive member by laser light according to image information, a detection unit arranged in a position facing the photosensitive member and configured to output positional information on the laser light. The detection unit includes a detection portion into which the laser light reflected by the photosensitive member is incident, and a control unit configured to calculate a positional deviation amount of an irradiation position on the photosensitive member which is irradiated by the laser light based on the positional information output by the detection unit, and control the scanning optical unit to correct the positional deviation of the irradiation position of the laser light.