An optical scanning device includes a first expander lens that expands beams emitted from a plurality of laser diodes in a main scanning direction. The beams emitted from the plurality of laser diodes are incident on the first expander lens, the first expander lens being a single lens. The plurality of laser diodes are disposed with optical paths of the beams from the plurality of light sources to a polygon mirror (rotary polygon mirror) overlapping each other in the main scanning direction when viewed from a direction along a rotary shaft of the polygon mirror.

A disclosed vertical cavity surface emitting laser device emits light orthogonally in relation to a substrate and includes a resonator structure including an active layer; and semiconductor multilayer reflectors disposed in such a manner as to sandwich the resonator structure between them and including a confinement structure which confines an injected current and transverse modes of oscillation light at the same time. The confinement structure has an oxidized region which surrounds a current passage region. The oxidized region is formed by oxidizing a part of a selective oxidation layer which includes aluminum and includes at least an oxide. The selective oxidation layer is at least 25 nm in thickness. The semiconductor multilayer reflectors include an optical confinement reducing section which reduces optical confinement in a transverse direction. The optical confinement reducing section is disposed on the substrate side in relation to the resonator structure.

A laser scanning unit and a color image forming apparatus using the laser scanning unit. The laser scanning unit includes a deflector that is rotatable to deflect a plurality of light beams that are incident on the deflector from a plurality of light sources at an angle with respect to a sub-scanning direction; at least one optical path changing member to change an optical path of each of the light beams deflected by the deflector; and a first f- lens to focus the light beam that passes through the optical path changing member onto a corresponding scanning target surface.

An optical scanning device includes: a light source that emits a laser beam modulated and driven according to an image forming signal; a scanning optical system that includes a polygon mirror to scan a surface of a photoconductor with the laser beam from the light source; a surface identifying unit that associates a sub-scanning position by the polygon mirror with each surface of the polygon mirror; and a light-amount adjusting unit that adjusts a light amount of the light source according to the sub-scanning position, for each surface of the polygon mirror.

A plastic optical element for an optical system of an optical scanner includes a plurality of optical effective portions through which a plurality of light beams transmit, respectively, formed on at least one of an incidence surface and an exit surface in a sub scan direction, and an optical ineffective portion formed between neighboring optical effective portions not to allow the light beams to transmit therethrough, and including an area in which a local contraction occurs at a time of resin molding.

An optical scanning system comprising first and second light sources emitting first and second light beams, a polygon mirror and first to fourth scanning lenses, wherein when an x-axis is in a direction of the central axis of the polygon mirror, a y-axis is in a scanning direction, P1 and P2 respectively represent reference points of deflection of the first and second light beams, L1 and L2 respectively represent a distance between P1 and the first scanning lens and a distance between P2 and the second scanning lens, Lp12 represents a distance between P1 and P2, h1 and h2 respectively represent thicknesses of the first and second scanning lenses and each of 1 and 2 represent an acute angle between a projection of the principal ray each of the first and second light beams onto an x-y plane,

[00001]$\frac{h2}{2.2}\left(2.Math.L1+L2+L_{p12}\right).Math.\tan 1\frac{h1}{2.2}\left(2.Math.L2+L1+L_{p12}\right).Math.\tan 2$

are satisfied.

An optical scanning device includes a laser driver, an offset value determiner, a bias current setter, and a laser driver controller. The laser driver controls a laser light emitter to increase or decrease an excess of a current over a bias current in response to an input analog signal. The offset value determiner determines an offset value of the analog signal input to the laser driver based on a target light quantity of the laser light emitter. The bias current setter controls the bias current of the laser driver to a setting value in accordance with laser characteristics or lens transmittance of the laser light emitter. The laser driver controller controls a light emission quantity of the laser light emitter by inputting, to the laser driver, the analog signal offset based on a signal of the determined offset value.

A scanning optical device includes: a first light source device configured to emit a first beam; a second light source device configured to emit a second beam; a deflector configured to deflect the first beam and the second beam; a first scanning optical system including a first scanning lens and configured to form an image on a first surface to be scanned using the deflected first beam; a second scanning optical system configured to form an image on a second surface to be scanned using the deflected second beam; a cover including a cover base wall and a first light-shielding wall; and a frame including a frame base wall and a second light-shielding wall. The first scanning lens has an incident surface and an emitting surface opposite the incident surface. The first light-shielding wall overlaps with the incident surface. The second light-shielding wall overlaps with the emitting surface.

An aperture unit includes a plurality of apertures which respectively cause a plurality of beam light sets that have passed through a plurality of lenses to pass therethrough. A laser scanner reflects and scans the plurality of beam light sets that have passed through the plurality of apertures. A support mechanism supports the aperture unit and is capable of changing a position of the aperture unit in a light traveling direction that is directed from the plurality of lenses toward the laser scanner and an angle of the aperture unit with respect to the light traveling direction.

An image forming apparatus includes a laser unit including a semiconductor laser, a polygon mirror, an LD driver, and an LD board including an LD reference potential section. The image forming apparatus includes a photoconductor drum, a controller configured to output a pulse-width modulation signal to indicate a reference potential, and a main board including a main reference potential section configured to provide the reference voltage of the controller, the main reference potential section being electrically connected to the LD reference potential section via a harness. The LD board includes a voltage generation circuit configured to generate a particular voltage, a switching circuit configured to output an ON-voltage and an OFF-voltage alternately based on the pulse-width modulation signal, and a smoothing circuit configured to generate the reference voltage by smoothing the ON-voltage and the OFF-voltage output by the switching circuit.