A light scanning device includes a polygon mirror, a first incidence optical system, a second incidence optical system, a first scanning lens, and a second scanning lens. The polygon mirror includes a deflection surface ensuring entering of the first light beam and the second light beam at an identical timing. Assuming that a reflection point of a light beam on the deflection surface at time point at which the light beam reflected at the deflection surface passes through a position on an optical axis of a scanning lens, the second scanning lens is superimposed on the first scanning lens at different positions in a main-scanning direction and an optical axis direction such that a circle locus is along an offset curved line. The circle locus is a locus of a point corresponding to the reference point by the rotation of the polygon mirror.

An image forming device includes a controller and a laser scanning unit. The laser scanning unit includes a light source for generating a laser beam for discharging a photoconductive member to create an electrostatic latent image. A first memory is housed on the laser scanning unit and stores data unique to the laser scanning unit and laser beam as characterized during production. A second memory in communication with the controller, and separate from the first memory, stores data characterizing a family of similar laser scanning units of a same type. The controller is configured to read both the first and second memories to generate data to compensate for energy variations along a scan path of the laser beam on the photoconductive member during use. The data substantially reduces energy variation from one scan path to a next.

A laser scanning unit for an image forming device includes a light source for emitting a laser beam, a scanning member having at least one reflective surface for scanning the laser beam onto an imaging surface across a plurality of scan lines, and driver circuitry for driving the light source to emit the laser beam. The driver circuitry has a first input for receiving a first signal indicating image information and a second input for receiving a second signal indicating shading information. The driver circuitry modulates the laser beam based on the first signal to form an image on the imaging surface corresponding to the image information and adjusts an output power of the modulated laser beam based on the second signal to substantially reduce energy variation across each scan line.

A laser scanning unit for an image forming device includes a light source for emitting a laser beam, a scanning member having at least one reflective surface for scanning the laser beam onto an imaging surface across a plurality of scan lines, and driver circuitry for driving the light source to emit the laser beam. The driver circuitry has a first input for receiving a first signal indicating image information and a second input for receiving a second signal indicating shading information. The driver circuitry modulates the laser beam based on the first signal to form an image on the imaging surface corresponding to the image information and adjusts an output power of the modulated laser beam based on the second signal to substantially reduce energy variation across each scan line.

An optical scanning apparatus includes a polygonal mirror configured to deflect a light beam emitted from a light source such that the laser beam scans a member to be scanned, a drive motor configured to rotate the polygonal mirror, aboard on which the polygonal mirror and the drive motor are mounted, an installation portion where the board is installed, a rubber member provided between the board and the installation portion, and an adjustment unit configured to position on the board with respect to the installation portion and to adjust inclination of the board with respect to the installation portion by deforming the rubber member.

A 2-D scanning system uses a fast-rotating raster-polygon as a single scanning component to produce straight scan lines over a 2-D image surface. An approach angle of incident light beams to the raster-polygon is selected to minimize pin-cushion distortion of scan lines introduced by polygon scanning on the image surface, and a tilt angle of the rotational axis of the raster-polygon is selected to position said polygon-scanning distortion symmetrically on the image surface. In addition, scan optics are configured to generate a predetermined amount of barrel distortion of scan lines on the image surface to compensate for pin-cushion distortion introduced by polygon scanning.

The optical scanning device includes a polygon mirror, one or more planar mirrors for reflecting the beam light so as to be led to a photosensitive drum, and a pressing member for pressing a back surface of a final planar mirror. The final planar mirror has a glass plate for allowing the beam light to pass therethrough and a reflection layer arranged on an opposite surface of the glass plate. The beam light passes through the glass plate and is reflected at the opposite surface side, so that a scanning line is curved on a surface to be scanned in a convex shape to one side in a sub-scanning direction. The final planar mirror is pressed by the pressing member so as to be curved, so that the scanning line on the surface to be scanned is adjustable to a flat shape.

An image forming apparatus performs periodic line based image transformation in order to correct for irregularities in a mirror and for mechanical disturbances that may occur during the rotation of the mirror. The irregularities of the mirror and the mechanical disturbances that occur during the rotation of the mirror may be measured at installation or may be measured during an operation of the image formation apparatus. The characteristics of the mirror are stored as configuration data, which is referenced by a direction of rotation. The image forming apparatus adjusts image data according to the configuration data. The adjustment may occur through data manipulation in stored image data. Alternatively, the adjustment may occur through the control of a pixel rate used to modulate the image data into a transmitted laser beam. The image data may be received by a host device or the image data may be generated by a scanner.

An optical scanning apparatus includes a light source, an optical deflector having a rotary polygon mirror to deflect a light beam from the light source, a scanning optical system configured to focus the light beam deflected by the optical deflector on a target surface, a sync detecting sensor configured to determine a write start timing on the target surface, and a processing unit configured to correct detection data of the sync detecting sensor based on a measured value of a time needed for one revolution of the rotary polygon mirror.

A light scanning unit may include a light source to emit a light beam and a beam deflector to reflect and scan the light beam emitted from the light source in a main scanning direction. The light scanning unit may also include a beam detecting sensor to detect a horizontal synchronization signal by receiving a part of the light beam and may include a circuit board disposed in part of a trajectory of the light beam such that the light beam is incident on a first surface of the circuit board. The circuit board may include a through-hole formed in the circuit board in the trajectory of the light beam. The beam detecting sensor may be mounted to a second surface of the circuit board which is opposite to the first surface of the circuit board. The light beam may be incident on the beam detecting sensor via the through-hole.