Abstract: Each of a plurality of pixels is formed with a group of a plurality of spots or a single spot. The barycentric position of each pixel is determined by the distribution of the spots or the position of the single spot. While the number of pixels on the exposure object is maintained in a first direction corresponding to the array direction of the light sources, an exposure feasible width on an exposure object can be adjusted in the first direction by setting the barycentric position at least in the first direction out of the first direction and a second direction that is the moving direction of the exposure object.

Abstract: A scanning optical system is configured such that at least a smaller value of the size in a main scanning direction of optical beams entering into an opening provided in an aperture member relative to the size of the opening of the aperture member in the main scanning direction and the size in a sub scanning direction of the optical beams entering into the opening relative to the size of the opening in the sub scanning direction is equal to or larger than 1 and equal to or smaller than 2.

Abstract: A velocity detecting device includes an image-pattern acquiring unit that includes a laser light source and an area sensor that acquires a one-dimensional or a two-dimensional image. The image-pattern acquiring unit includes a lens between a moving member and the area sensor, irradiates a beam emitted from the laser light source to the moving member to make a scattering light of the moving member scattered from the moving member on the area sensor by using the lens, and acquires an image pattern at a predetermined time interval in association with movement of the moving member. A velocity calculating unit calculates the velocity of the moving member by computing the image pattern acquired by the image-pattern acquiring unit. The lens is a reduced optical system that projects a reduced object onto the area sensor.

Abstract: A multibeam optical scanning device includes a plurality of light sources; a collimating lens; an aperture; a cylinder lens; a light deflecting unit; a scanning optical system; and a phase adjusting element. The phase adjusting element performs phase adjustments of wavefronts of the light beams to expand a depth allowance without substantially increasing a beam spot size of each of the beam spots on the scanning surface.

Abstract: A light scanning device includes: a light source; an aperture stop regulating a width of a light beam emitted from the light source; a deflector deflecting and scanning the light beam emitted from the light source; at least one scanning lens forming an image on a scanned surface with the light beam deflected and scanned; and a phase-type optical element. In the light scanning device, a phase modulation portion is provided to at least a portion of the phase-type optical element, and a phase difference between the phase modulation portion and a region other than the phase modulation portion is not ? [radian]. Thus, asymmetry in a curve representing the relationship between a beam spot diameter and defocus can be corrected to reduce variation of the beam spot diameter with respect to the defocus. Consequently, highly-accurate light scanning can be performed.

Abstract: An optical scanning device has a light source, a unit configured to deflect a light beam from the light source; and a system including at least two scanning lenses and configured to guide the light beam deflected to a surface to be scanned. One of the scanning lenses closest to the deflecting unit has a positive refractive power in a main scanning direction and zero or approximately zero refractive power in a sub scanning direction, and another one of the scanning lenses closest to the surface has a negative refractive power in the main scanning direction, a positive refractive power in the sub scanning direction, and an incidence surface in the sub-scanning direction which is convex toward the deflecting unit.

Abstract: In a beam-spot position compensation method for use in an optical scanning device which scans a surface of a photosensitive medium by a light beam emitted by a light source, a plurality of sections are defined by dividing a scanning region on the scanned surface. An emission timing of the light beam for every section is adjusted so that a spacing between beam-spot positions corresponding to pixels of start and end of each section is changed by a predetermined amount. The sparseness or denseness of beam-spot position spacings of the plurality of sections in the whole scanning region is compensated.

Abstract: A laser beam scanning device is disclosed. The laser beam scanning device includes a diffraction optical element which forms a pattern of a diffraction image including two images extending in a direction corresponding to the sub scanning direction and one image extending in a direction inclined by ? (0<?<90°) from the direction corresponding to the sub scanning direction by inputting a laser beam which is led to a surface of a photoconductor drum, and a light receiving element which receives the pattern of the diffraction image.

Abstract: An aperture has an aperture opening that transmits a predetermined portion of a light beam. A phase optical element changes a phase of a portion of a light beam. A scanning lens focuses the light beam into a beam spot on a scanning surface. The phase optical element has a function of increasing light intensity of a side-lobe of the scanning beam near the scanning surface. The aperture opening is set to satisfy 0.03?(SR?SA)/SR?0.20, where SR and SA are areas of a rectangle circumscribing the aperture opening and the aperture opening, respectively. The function of the phase optical element and the aperture expand a depth allowance of the beam spot.

Abstract: An aperture has an aperture opening that transmits a predetermined portion of a light beam. A phase optical element changes a phase of a portion of a light beam. A scanning lens focuses the light beam into a beam spot on a scanning surface. The phase optical element has a function of increasing light intensity of a side-lobe of the scanning beam near the scanning surface. The aperture opening is set to satisfy 0.03?(SR?SA)/SR?0.20, where SR and SA are areas of a rectangle circumscribing the aperture opening and the aperture opening, respectively. The function of the phase optical element and the aperture expand a depth allowance of the beam spot.

Abstract: At least one of a coupling lens and a cylindrical lens has a diffraction lens surface having a ring-band structure with a height h between adjacent ring-bands. The diffraction lens surface has an area A having a shape similar to that of the ring-band structure with a height h?, where h?h?. The ring-band structure has a function of correcting a fluctuation in focal position of the scanning beam on the scanning surface, and the area A has a function of expanding a focal depth of a light spot on the scanning surface.

Abstract: A coupling lens collimates an optical beam emitted from a laser light source. An aperture shields a peripheral light flux area of the collimated optical beam. A phase adjusting element partially changes a phase of wavefront of the optical beam. An auxiliary aperture is formed on an outer side of a normalized aperture size in at least one of a main scanning direction and a sub-scanning direction. The phase adjusting element is formed in a parallel plate, and changes at least a phase of wavefront of a peripheral portion of the optical beam to compensate decreases of the beam spot size and the depth allowance caused by the auxiliary aperture.

Abstract: A multibeam optical scanning device includes a plurality of light sources; a collimating lens; an aperture; a cylinder lens; a light deflecting unit; a scanning optical system; and a phase adjusting element. The phase adjusting element performs phase adjustments of wavefronts of the light beams to expand a depth allowance without substantially increasing a beam spot size of each of the beam spots on the scanning surface.

Abstract: An optical scanning device acquires a displacement amount of each of scanning light beams in the main scanning direction, and corrects, based on the displacement amount, writing energy density at a write position such that a variation in image density due to a variation of the displacement amount is reduced. The light beams are used for scanning a target surface to write image data on the target surface. The writing energy density is an amount of light per unit surface area of the target surface.

Abstract: A coupling lens collimates an optical beam emitted from a laser light source. An aperture shields a peripheral light flux area of the collimated optical beam. A phase adjusting element partially changes a phase of wavefront of the optical beam. An auxiliary aperture is formed on an outer side of a normalized aperture size in at least one of a main scanning direction and a sub-scanning direction. The phase adjusting element is formed in a parallel plate, and changes at least a phase of wavefront of a peripheral portion of the optical beam to compensate decreases of the beam spot size and the depth allowance caused by the auxiliary aperture.

Abstract: An optical scanning device includes a light source, a pre-deflection optical system, a polygon mirror, and a scanning optical system. The pre-deflection optical system includes a coupling lens and a diffraction lens. A light output surface of the coupling lens is a phase shifting surface, while a light output surface of the diffraction lens is a diffractive surface. The absolute value of the focal length of the diffraction lens is longer than the absolute focal length of the coupling lens.

Abstract: A light scanning device includes: a light source; an aperture stop regulating a width of a light beam emitted from the light source; a deflector deflecting and scanning the light beam emitted from the light source; at least one scanning lens forming an image on a scanned surface with the light beam deflected and scanned; and a phase-type optical element. In the light scanning device, a phase modulation portion is provided to at least a portion of the phase-type optical element, and a phase difference between the phase modulation portion and a region other than the phase modulation portion is not ? [radian]. Thus, asymmetry in a curve representing the relationship between a beam spot diameter and defocus can be corrected to reduce variation of the beam spot diameter with respect to the defocus. Consequently, highly-accurate light scanning can be performed.

Abstract: An optical scanning device includes, in an effective scanning area in the target surface, a mechanism that causes a scanning speed at each scanning position with respect to a scanning speed at an approximately center in the effective scanning area to be within a range under a predetermined condition.

Abstract: A scanning optical system is configured such that at least a smaller value of the size in a main scanning direction of optical beams entering into an opening provided in an aperture member relative to the size of the opening of the aperture member in the main scanning direction and the size in a sub scanning direction of the optical beams entering into the opening relative to the size of the opening in the sub scanning direction is equal to or larger than 1 and equal to or smaller than 2.

Abstract: An optical scanning unit includes a light source that emits a light beam, a light deflector that deflects the light beam from the light source, and a scanning optical system that focuses the light beam deflected by the light deflector on a scanning surface. The light beam from the light source is at an angle in a secondary scanning direction with respect to a normal to a reflecting surface of the light deflector. At least one surface of the scanning optical system does not have a curvature in the secondary scanning direction, being tilted and decentered in the secondary scanning direction.