Abstract: A system and a method for manipulating a beam of an Advanced Charge Controller module in different planes in an e-beam system are provided. Some embodiments of the system include a lens system configured to manipulate a beam in the tangential plane and the sagittal plane such that the beam spot is projected onto the wafer with high luminous energy. Some embodiments of the system include a lens system comprising at least two cylindrical lens.

Abstract: A laser eye surgery system includes a computer which scans a focused laser beam in a trajectory over a reticle or target and determines beam quality via laser light reflected from the target. The target may have a grid pattern of lines, with the diameter of the focused laser beam determined based on a time interval for the scanned beam to move onto a line of the grid pattern. Methods for measuring beam quality in a laser eye surgery system provide a direct, quantitative quality measurement of the focused laser beam, and may be performed quickly and automatically. Using scanning mirror position information together with signals resulting from laser light reflected from the target, the laser eye surgery system may also be calibrated.

Abstract: Optical scanner and electrophotographic image forming device are provided. The optical scanner includes a light source; and a first optical unit, a deflection apparatus, and an f-? lens, which are sequentially arranged along a primary optical axis direction of a light beam emitted from the light source. The light beam emitted from the light source is focused onto a scanning target surface after sequentially passing through the first optical unit, the deflection apparatus, and the f-? lens. Optical scanning directions of the light beam emitted from the light source include a primary scanning direction and a secondary scanning direction which are perpendicular to each other, and along the primary scanning direction, the f-? lens satisfies following expressions: SAG1>0, SAG2>0, and 0<(SAG1+SAG2)/d<0.8.

Abstract: The present disclosure is generally directed to a lens clip that defines at least one mounting surface for coupling to and supporting an array of optical components, e.g., a laser diode and associated components, and an optical lens slot to receive and securely hold an array of optical lenses at a predetermined position relative to the optical components to ensure nominal optical coupling. The optical lens slot includes dimensions that permit insertion of each optical lens into the same and restrict travel along one or more axis. Accordingly, disposing an optical lens within the lens slot ensures correct alignment along at least two axis, e.g., Z and X, with the third axis (e.g., Y) extending parallel along the slot to permit lateral adjustment of each lens.

Abstract: An F-theta lens includes a diffractive optical element and a plurality of spherical lenses. The diffractive optical element includes multi-level diffractive structure having three or more levels and defined on a surface thereof, and the diffractive optical element is arranged before the spherical lenses on a path of a laser beam.

Abstract: A light deflecting device includes a rotary polyhedron and a cover that covers the rotary polyhedron. The cover includes an opening facing a peripheral surface of the rotary polyhedron. Light beam is irradiated to the peripheral surface of the rotary polyhedron through the opening of the cover, and the rotary polyhedron allows the light beam to be deflected and scanned with respect to an object to be irradiated while rotating about an axial center thereof. When an opening angle of the opening centered on the axial center of the rotary polyhedron is ? and n is set as a natural number, ? satisfies the following Equation (1) ?>((360°/the number of surfaces of the rotary polyhedron)×n)×0.83 . . . (1) and Equation (2) ?<((360°/the number of surfaces of the rotary polyhedron)×n)×1.17 . . . (2).

Abstract: Described herein are systems and methods of determining a distance between an object depicted in an image and an imaging device that captured that image. In particular, the disclosure discusses that an image may be separated into multiple derivative images, each of which is associated with a different wavelength of light. In some embodiments, an image may be separated into images associated with wavelengths of primary colors (e.g., red, green, and blue). Once separate images have been created, a sharpness value may be determined for each image. A distance between the object and the imaging device may then be calculated based on sharpness values associated with each of the separate images.

Abstract: An optical scanning apparatus includes a deflector configured to deflect a light beam from a light source and scan a surface to be scanned in a main-scanning direction and a single imaging optical element configured to guide the light beam deflected by the deflector to the surface to be scanned. Scanning speeds of the light beam on the surface to be scanned at an on-axis image height and at an off-axis image height are different from each other, and conditions 0.0<(R1±h/2+R2±h/2)/(R1±h/2?R2±h/2)<1.7 and 0.8<h/TC<2.0 are satisfied.

Abstract: This rotary drive apparatus is arranged to rotate a flywheel arranged to support an optical component arranged to reflect incoming light coming from a light source or allow reflected light obtained by reflection of the incoming light to pass therethrough, and includes a motor including a rotating portion, and the flywheel, the flywheel being supported by the motor and arranged to rotate about a central axis extending in a vertical direction. The flywheel includes at least one recessed portion recessed axially downward from an upper surface of the flywheel. The flywheel further includes at least one weight arranged in the at least one recessed portion.

Abstract: A method includes determining a set of pattern position errors between (i) a set of expected pattern positions of a calibration pattern on a laser target situated in a laser processing field of a laser system and produced based on a set of initial scan optic actuation corrections associated with a scan optic of the laser system and (ii) a set of measured pattern positions of the calibration pattern, determining a set of scan optic actuation rates based on the set of initial scan optic actuation corrections, and updating the set of initial scan optic actuation corrections based on the set of scan optic actuation rates and the set of pattern position errors so as to form a set of updated scan optic actuation corrections that is associated with a reduction of at least a portion of the set of pattern position errors.

Abstract: A method of marking the surface of a mechanical part with a predefined graphic having a holographic type effect, the method including using a laser source to apply a succession of laser pulses to the outside surface of a part for marking, with different masks being interposed between the laser source and the outside surface of the part, each mask having a particular pattern, each laser pulse having a power density of at least 20 MW/cm2 and a duration that is less than or equal to 100 ns.

Abstract: A printing assembly comprises a medium support surface, a guide assembly and a carriage support structure for moveably supporting a print head carriage on the guide assembly. The guide assembly is arranged to move the print head carriage in a carriage plane, which carriage plane is parallel to the medium support surface. The guide assembly comprises a guide beam; and a guide rail arranged on the guide beam. The guide rail and the guide beam each extend in a scanning direction. The printer carriage support structure comprises a guide frame arranged on the guide rail and the guide frame is moveable in the scanning direction and extends in the scanning direction between a first support position and a second support position. The guide frame is supported on the guide rail at said first support position and at said second support position. A carriage frame is moveably supported on the guide rail through the guide frame.

Abstract: An optical scanning apparatus includes a deflector configured to respectively deflect first and second light beams by a first deflection surface and scan first and second scanned surfaces in a main scanning direction, and first and second imaging optical systems configured to respectively collect the first and second light beams deflected by the deflector to the first and second scanned surfaces. The first and second imaging optical systems include a shared multistage lens including first and second optical surfaces arranged in a sub-scanning direction to which each of the first and second light beams enters, the second scanned surface is disposed on a position closer to the deflector than the first scanned surface, and a second optical path length from the first deflection surface to the second scanned surface is longer than a first optical path length from the first deflection surface to the first scanned surface.

Abstract: An apparatus includes a laser diode, a near field transducer configured to direct light emitted from the laser diode to a magnetic recording medium, and a power source configured to provide modulated current to the laser diode.

Abstract: There is provided an imaging element that photographs multiple viewing point images corresponding to images observed from different viewing points and an image processing unit separates an output signal of the imaging element, acquires the plurality of viewing point images corresponding to the images observed from the different viewing points, and generates a left eye image and a right eye image for three-dimensional image display, on the basis of the plurality of acquired viewing point images. The image processing unit generates parallax information on the basis of the plurality of viewing point images obtained from the imaging element and generates a left eye image and a right eye image for three-dimensional image display by 2D3D conversion processing using the generated parallax information. By this configuration, a plurality of viewing point images are acquired on the basis of one photographed image and images for three-dimensional image display are generated.

Abstract: An optical writing device includes a light source, an optical deflector that deflects and scans light from the light source, a pre-deflector optical system that guides the light from the light source to the deflector, a post-deflector optical system that guides the scanned light to a target surface, a cover covering the deflector and including a first opening and a second opening provided at different positions, and a housing housing these optical elements. Light traveling from the light source to the deflector and the light scanned by the deflector are transmitted through the first opening but not through the second opening. During the rotation of the deflector, a forced inflow of air flowing from outside to inside the cover is generated in the first opening, and a discharged airflow flowing from inside to outside the cover is generated in the second opening.

Abstract: An optical device includes: a light source that emits a light beam; a deflector that deflects the light beam in a main-scanning direction; and a scanning/image-forming optical system that includes a scanning lens that causes the light beam deflected by the deflector to converge to a scanned surface to form an image on the scanned surface. The scanning lens has refractive index gradient. At least one surface of the scanning lens is a tilt-decentered surface that has a tilt angle, which depends on a position in the main-scanning direction, in a sub-scanning direction. The tilt angle is set so as to compensate for variation, which results from the refractive index gradient, in direction of the light beam in the sub-scanning direction.

Abstract: A scanning unit includes a scanning member having at least one reflective surface for reflecting light incident thereon, a plurality of light sources controllable to emit light beams onto the at least one reflective surface, and first and second scan lenses for receiving and focusing the light beams reflected from the at least one reflective surface. Each of the first and second scan lenses has a light exit surface having a first curved surface section and a second curved surface section defining therebetween a junction line extending between opposed longitudinal ends of each of the first and second scan lenses. The junction line is nonlinear.

Abstract: A light beam emission apparatus separates, via a half mirror, apart of a laser beam emitted from a semiconductor laser towards a photosensitive member, guides the separated laser beam to an optical sensor to detect a light quantity, and controls the light quantity based on the detected result. The light beam emission apparatus includes a first light blocking member located between the semiconductor laser and the half mirror, and a second light blocking member located between the half mirror and the optical sensor.

Abstract: A light scanning unit and an electrophotographic image forming apparatus are provided. The light scanning unit includes a light source emitting the light beams according to an image signal, an incident optical system including a flux-limiting element limiting the flux of light beams emitted by the light source, an optical deflector deflecting the light beams emitted by the light source in a main scanning direction, and an image forming optical system including a scanning optical element imaging the light beams deflected by the optical deflector on a scanning target surface, the light scanning unit forming an electrostatic latent image by scanning the light beams to the scanning target surface of the image bearing member. The scanning optical element of the scanning optical elements of the image forming optical system is eccentrically arranged from a central optical axis of the image forming optical system in a sub-scanning direction.

Abstract: A resin BD lens having a property of refracting a light beam in a direction corresponding to a main scanning direction may cause a variation in generation timing difference among a plurality of horizontal synchronization signals and accordingly degrade accuracy to correct the starting position of an electrostatic latent image. The present invention uses a glass BD lens having a property of refracting a light beam in a direction corresponding to the main scanning direction.

Abstract: An optical scanning device includes a plurality of stations, each of which includes an light source, a deflector (polygon scan), a scanning optical element, and a housing. The light source emits a light beam to a plurality of surfaces to be scanned. The deflector deflects light beams emitted from the light source. The scanning optical element scans the surfaces to be scanned with light spots of the optical beams deflected by the deflector. The housing houses therein the light source, the deflector, and the scanning optical element. The scanning optical element is secured to the housing so that directions of scanning-line curves caused by temperature change match between the surfaces to be scanned.

Abstract: An optical scanning device has a light deflector deflecting a light beam from a light source, a synchronization detection sensor determining timing of starting scanning in main scanning direction based on timing of detecting the light beam scanned in main scanning direction by the light deflector, and a pre-sensor imaging optical system imaging the light beam reflected from the light deflector on the synchronization detection sensor. The pre-sensor imaging optical system moves the imaging position of the light beam on the synchronization detection sensor in a direction making the timing of detecting the light beam earlier or later according to whether variation in temperature causes the magnification of the scanning optical system in main scanning direction to increase or decrease respectively.

Abstract: An optical scanning apparatus includes a light source configured to emit a light beam, a scanning unit configured to deflect the light beam from the light source so as to scan a photosensitive member, an optical lens configured to guide the light beam scanned by the scanning unit onto the photosensitive member, and a lens supporting unit having a fixing portion configured to fix the optical lens, wherein the lens supporting unit includes a movable supporting portion configured to restrict movement of the optical lens in a direction perpendicular to a scanning direction of the light beam and an optical axis direction of the optical lens, to restrict movement of the optical lens in the optical axis direction, and to support the optical lens movably in the scanning direction.

Abstract: The calculation unit calculates the time interval between the time at detecting the light beam reflected by the reflective surface of the rotatory polyhedron incident on the BD sensor by the light beam detecting unit and the time at detecting the light beam reflected by the reflective surface incident on the optical sensor in the light source by the return light beam detecting unit. The scan adjusting unit adjusts the luminescence time of the light source for scanning the light beam on the surface to be scanned based on the time interval calculated by the calculation unit.

Abstract: An optical scanning device includes: a light source unit; a light deflecting unit that deflects a light beam emitted from the light source unit; a scanning optical device that focuses the light beam deflected by the light deflecting unit on a scanned surface; and a light shielding member. The scanning optical device is provided in a direction in which a sound pressure level of a noise caused by rotation of a rotating polygon mirror included in the light deflecting unit is highest.

Abstract: A laser label printer for use with a laser markable medium includes a laser-diode fiber-coupled to an optical train, which includes a focusing lens for focusing the radiation on the medium. The focusing lens is traversed across the medium, with incremental motion of the medium between traverses, for line by line printing of the label. The printer includes a feature for protecting the focusing lens from contamination, and self-diagnostic and adjustment features.

Abstract: An single-pass imaging system utilizes a light source, a spatial light modulator and an anamorphic optical system to form a substantially one-dimensional high intensity line image on an imaging surface (e.g., the surface of a drum cylinder). The light source and the spatial light modulator are used to generate a relatively low intensity two-dimensional modulated light field in accordance with an image data line such that each pixel image of the line is elongated in the process (Y-axis) direction. The anamorphic optical system utilizes a cylindrical/acylindrical optical element to anamorphically image and concentrate the modulated light field in the process direction to form the substantially one-dimensional high intensity line image. The line image is generated with sufficient energy to evaporate fountain solution from the imaging surface. The imaging system simultaneously generates all component pixel images of the line image, thus facilitating a printing apparatus capable of 1200 dpi or greater.

Abstract: An exposure device includes at least one light emitting element that emits light in a normal direction of the substrate; at least one hologram element that is recorded on a recording layer arranged on the substrate to diffract light emitted from the light emitting element and condense the diffracted light on a condensing point on a normal line of the light emitting element; and at least one light inhibiting part that is arranged on a straight line that connects the light emitting element and the condensing point such that the light diffracted by the hologram element passes through the outside of the light inhibiting part and condenses at the condensing point, to inhibit transmission of zeroth-order light that goes straight toward the condensing point from the light emitting element without being diffracted by the hologram element.

Abstract: Disclosed are methods, systems, and/or apparatus for the collective marking of a surface by two or more laser beams generated by a laser controller. A method includes receiving one or more input signals from a controller of the laser system. The method also includes adjusting a first mirror through a first galvanometer scanner, a second minor through a second galvanometer scanner, a third mirror through a third galvanometer scanner, and a fourth mirror through a fourth galvanometer scanner based on the one or more input signals. The method further includes steering, through the first mirror and the second mirror, a first laser beam generated by the controller and transmitted to a marking head through a beam delivery vessel; and steering, through the third mirror and the fourth minor, a second laser beam generated by the controller and transmitted to the marking head through another beam delivery vessel.

Abstract: An optical scanning device includes a light source, a deflector, an incident optical system and one scanning lens. The scanning lens includes a first face and a second face. In a main scanning direction cross section of the scanning lens, when a scanning range is separated, with on axis as a reference, into an image height region of a first direction and an image height region of a second direction that is opposite to the first direction, the incident optical system is disposed on a side of the image height region of the first direction. Curvature of the first face in a sub scanning direction cross section decreases from on axis toward off axis in the main scanning direction, and curvature of the second face in the sub scanning direction cross section increases from off axis of the first direction toward the second direction in the main scanning direction.

Abstract: An optical scanning apparatus includes a light source, a deflector that deflects a light beam in a main scanning direction, an incident optical system that makes the light beam enter the deflecting surface in a sub-scanning section, and an imaging optical system that includes at least one imaging optical element and condenses the light beam onto a surface to be scanned, in which at least one of an incident surface and an exit surface of the at least one imaging optical element is decentered in the sub-scanning section such that an origin position line exists in a region sandwiched between marginal rays at two sub-scanning direction ends of the light beam, the origin position line being extended in the main scanning direction and passing through an origin of an aspherical surface formula defining a surface shape of each of the incident surface and the exit surface in the sub-scanning section.

Abstract: Image forming apparatus 10 of the present invention is an apparatus for forming an image on a surface of recording medium P by applying laser light to recording medium P, the apparatus including a plurality of light sources 31 each of which emits laser light, a plurality of optical fibers 23 and 42 through which laser light respectively emitted from light sources 31 propagates, holder 43 that holds optical fibers 42, and fly-eye lens 50, cylindrical lens array 60, aperture array 70, lens 80a and lens 80b through which laser light emitted from end surfaces of optical fibers 42 passes, wherein each of apertures 71 of aperture array 70 is rectangular.

Abstract: A molded part prepared by a mold transfer method using a die, including a surface which includes a slope, wherein a direction of a normal line of the slope is different from a die releasing direction; and a pattern which is formed on the surface and which includes grooves located on a portion of the slope so as to extend along the slope in the slanting direction of the slope. An optical element, which has an anti reflection function, including the molded part mentioned above, wherein the interval between two adjacent grooves is not greater than the wavelength of light irradiating the optical element. An optical device including a light source configured to emit light; and the optical element mentioned above which processes the light emitted by the light source.

Abstract: There are provided a lens, a method of fabricating the lens, and a light scanning unit. The lens includes a lens portion having an effective optical surface, and a gate-side flange portion between the lens portion and a gate-side end of the lens. If the lens is disposed between two polarizers configured to polarize light linearly in perpendicular directions and is illuminated in an optical axis direction, interference fringes are generated on the lens, and peripheral interference fringes of the interference fringes extend continuously from the gate-side end and are longer than the gate-side flange portion.

Abstract: An optical scanning apparatus, including: a light source including a plurality of light emitting parts; a deflector including a deflecting surface; a first optical system configured to cause the plurality of light beams to enter the deflecting surface at an oblique angle; and a second optical system configured to focus the light beams on a surface to be scanned, in which: the light emitting parts are arranged away from each other; the second optical system includes an optical element including at least one optical surface having a non-arc shape, so that a wave optics interval between scanning lines based on barycentric positions of spot images on the surface to be scanned is aligned along the main scanning direction; the non-arc shape of the at least one optical surface of the optical element within the sub-scanning section is defined by a predetermined condition.

Abstract: An optical print head having a substrate on which multiple light sources aligned in a main scanning direction are mounted to emit beams of light in a direction perpendicular to a surface of the substrate; a lens array to focus the beams of light on an image bearing member to form an image thereon; a housing having a guiding portion extending in the main scanning direction to position the substrate and the lens array; a cleaner to clean a light-emitting surface of the lens array while moving in the main scanning direction; a moving device to move the cleaner; and a supporting member to support the housing and the cleaner. The supporting member rotatably supports the cleaner about a shaft and the guiding portion contacts the cleaner against the light-emitting surface of the lens array with a constant force over the main scanning direction during cleaning of the light-emitting surface.

Abstract: According to one embodiment, there is provided an imaging element array including an imaging element group in which a plurality of imaging elements are aligned, each of the imaging elements including an integrally molded input portion, an output portion, and a reflective portion, collecting light input to the input portion, reflecting the light by the reflective portion near a position where light flux is downsized, and outputting the reflected light from the output portion to form an image at an image point, and an inhibiting portion which is formed around the reflected portion in the imaging element group to inhibit light other than the light reflected by the reflective portion from traveling to the output portion.

Abstract: The invention provides an exposure head including: a light emitting unit; an imaging unit that allows light from the light emitting unit to enter through an incidence plane and exit from an exit surface so as to form an image at a predetermined position; and a transparent layer provided between the light emitting unit and the imaging unit, while contacting each of the light emitting unit and the imaging unit; the transparent layer having a thickness such that an optical distance between the light emitting unit and the incidence plane of the imaging unit becomes a working distance of the imaging unit.

Abstract: A first lens array unit includes a first lens array plate and a second lens array plate in which a plurality of lenses are provided in the main scanning direction, and a first light shielding member piece and a second light shielding member piece provided with a plurality of through holes corresponding to the lenses. The first lens array plate, the second lens array plate, the first light shielding member piece, and the second light shielding member piece are formed as one piece. The lens array is built by bending joints joining the lens array plates and the light shielding member pieces such that the lens is located to directly face the corresponding through hole.

Abstract: In an exposure device, a light source device having multiple light emitting devices arranged in one-dimensional or two-dimensional directions projects light against an image bearing member. A light source holding member holds the light source device in place. An optical device condenses the light projected from the light source device onto the image bearing member. An optical device holding member holds the optical device to maintain a predetermined gap between the optical device and the light source device on the light source holding member. A positioning member supports the light source holding member above the image bearing member to maintain a predetermined gap between the image bearing member and the light source device on the light source holding member. When seen from a light emitting point of the light source device, a position at which the positioning member supports the light source holding member is opposite the image bearing member.

Abstract: A pupil splitting lens that splits a pupil of a light beam from a deflector into a plurality of light beams in a main scanning direction of the deflector and a pupil splitting lens that splits the light beam into a plurality of light beams in a sub-scanning direction are disposed relative to a light detection element. The light detection element detects image forming positions of the four light beams formed as a result of the splitting by the plurality of pupil splitting lenses. A CPU determines the amount of focus shift and the amount of image forming position shift from these four image forming positions.

Abstract: An image forming apparatus wherein a photosensitive drum is located such that its circumferential surface is exposed to light at a position between an image surface of light that is emitted from an LED at a distance of a half of a pitch of a plurality of rod lenses from a first rod lens of the plurality of rod lenses and that passes through the first rod lens and an image surface of light that is emitted from an LED at a distance of the pitch of the plurality of rod lenses from a second rod lens of the plurality of rod lenses and that passes through the second rod lens.

Abstract: According to one embodiment, an optical scanning device includes plural light sources, a polygon mirror, a first lens, a first reflection mirror, and a second lens. The polygon mirror deflects lights emitted from the plural light sources in a predetermined direction. The first lens allows the lights emitted from the plural light sources and deflected by the polygon mirror to pass. The first reflection mirror reflects the lights passed through the first lens in a direction different from the deflecting direction of the polygon mirror. The second lens receives incidence of the lights reflected by the first reflection mirror from a direction different from an incident direction of the first lens and allows, with one lens, the lights emitted from the plural light sources to pass.

Abstract: An optical scanner includes: a light reflecting section having light reflectivity; a movable section which includes the light reflecting section and can be displaced; two link sections connected to positions of ends of the movable section, the positions facing each other; a supporting section supporting the link sections; and a displacement providing section turning the two link sections, wherein each link section includes a turnable drive section, and a shaft section connecting the movable section and the drive section and bending in a thickness direction of the movable section by turning of the drive section.

Abstract: An optical writer includes a light source, an optical part, a housing, and an elastically deformable retainer. The light source projects light against a target. The optical part is disposed on a light path between the light source and the target. The housing houses the light source and the optical part. The elastically deformable retainer is detachably fixed to the housing and includes a plurality of contact portions on an inner surface of the retainer to hold the optical part. The retainer elastically deforms to separate at least one of the contact portions from other contact portions to hold the optical part by the plurality of contact portions.

Abstract: An optical scanning apparatus and an image forming apparatus having the optical scanning apparatus includes a before-light-deflecting-unit optical system and a scanning optical system. The optical system includes a first optical device, a second optical device made of a resin material which has an anamorphic negative refracting power in a deflection scanning direction and a deflection scan perpendicular direction and has a larger refracting power in the deflection scan perpendicular direction than a refracting power in the deflection scanning direction, and a third optical device made of a glass material which has substantially no refracting power in the deflection scanning direction and a positive refracting power in the deflection scan perpendicular direction. An interval of the scanning lines formed on the scanned surface is adjusted by displacement of the second and third optical devices in an optical axis direction of the before-light-deflecting-unit optical system.

Abstract: An optical scanning unit may include a light source unit configured to emit a light beam, an optical housing configured to receive and support the light source unit, an optical device configured to deflect the light beam and to focus the light beam on a light receiving member, and a fixing member configured to fix the light source unit to the optical housing by applying pressure to the light source unit, wherein the pressure is applied in a direction, which is substantially perpendicular to an optical axis direction of the light source unit.

Abstract: A housing (30) includes a base portion (30a) for installation of an optical beam emission unit (31), a light guiding unit (35a-39a, 35b-39b), and a deflection unit (32, 33), and a cover portion (30b, 30c) that includes an indented heat emission channel (30b1, 30c1) that transmits heat in an inner portion of the housing (30) to a fluid.

Abstract: A plurality of light sources, a light deflector, and a single scan lens. The light deflector deflects a plurality of light beams emitted from the light sources by a same face for scanning a plurality of to-be-scanned portions simultaneously. The single scan lens receives the light beams from the light deflector and focuses the light beams onto each of the plurality of to-be-scanned portions to scan the to-be-scanned portions simultaneously. The single scan lens is used in common for the light beams, and has one incidence plane and a plurality of exit planes in a sub-scanning direction separately prepared in the sub-scanning direction for each of the to-be-scanned portions. The incidence plane has a refractive power of the lens in the sub-scanning direction decreasing toward peripheral portions in the main scanning direction. The exit planes have positive refractive power in the main and sub-scanning directions.