In an optical scanning device, an outer wall closest to a circumscribed circle of a rotating polygon mirror has a space in a position facing to a position of a reflection surface of the rotating polygon mirror in an axial direction of a rotating shaft. A part of a cover is provided in a position farther from the circumscribed circle than the outer wall so as to close the space, when the optical scanning device is viewed in a direction perpendicular to the axial direction of the rotating shaft.

An optical scanning apparatus includes a first rotating polygonal mirror that deflects a light beam such that the light beam scans a surface of a first image carrier, and a second rotating polygonal mirror that deflects a light beam such that the light beam scans a surface of a second image carrier. The optical scanning apparatus further includes a first phase control unit that performs phase control of the first rotating polygonal mirror based on a first detection signal output from a first detection unit and a first target phase, and a second phase control unit that performs phase control of the second rotating polygonal mirror based on a second detection signal output from a second detection unit and a second target phase, which is set with respect to the first target phase.

An image forming apparatus includes an image forming device and a control device. The image forming device forms an image on a recording medium. The control device controls an image forming process. The control device includes circuitry. The circuitry changes a plurality of partial images in a target image into a certain state. The target image is to be formed on the recording medium. The plurality of partial images are to be formed peripheral to a plurality of pattern images. Each of the plurality of pattern images is to be formed at a certain position on the recording medium. The circuitry further controls the image forming device to form the target image including the changed plurality of partial images and the plurality of pattern images on the recording medium, and corrects a position of the target image based on a detection result of the formed plurality of pattern images.

Provided is an optical scanning device. The optical scanning device includes a swingable reflection unit; a blocking unit that is provided in the reflection unit to move in linkage with the reflection unit; and a sensor unit that includes an output unit configured to output a detection target and a detection unit configured to detect the detection target, wherein, when the reflection unit is in a predetermined swing angle range, the blocking unit blocks a path of the detection target between the output unit and the detection unit.

A calibrating method includes controlling a laser radiator to radiate calibration laser light to an object such that a pattern is projected in a laser coordinate system with respect to the laser radiator; controlling a camera to obtain a first image of first light points of the calibration laser light projected on a surface of the object when the object is in a first position; and controlling the camera to obtain a second image of second light points of the calibration laser light projected on the surface of the object when the object is in the second position. A positional relationship between the laser coordinate system and the camera coordinate system is calculated based on the three-dimensional positions of the first light points and the three-dimensional positions of the second light points.

An image forming apparatus includes first and second light sensors positioned in a laser scanning system of at least one color, such that scanned light is detected by the first light sensor and then by the second light sensor and light sensing surfaces of the first and second light sensors are not parallel, and a control unit connected to the first and second light sensors and configured to determine a time difference in the timing of light detection by the first and second light sensors and to execute a color position shift operation upon determining that the time difference is greater than a first threshold value.

An image forming apparatus including a first output unit configured to detect a light beam deflected by a rotary polygon mirror rotated by a drive unit to output a first signal, a second output unit configured to output a second signal to be used as a reference, and a first controller configured to perform the phase control based on the first signal and the second signal. The phase control is performed in accordance with a condition set based on a rotation speed of the drive unit corresponding to an image forming speed by outputting a drive signal having a predetermined pulse width to the drive unit to accelerate or decelerate the drive unit so that the first signal and a position signal, based on the second signal, substantially match. The condition being a pulse width of the drive signal and/or a frequency of performing the phase control.

An optical scanning apparatus includes a deflector to deflect laser light emitted from a light source for scanning, and a detection unit attached to a substrate provided with a through-hole for the detection unit to receive laser light that has passed through the through-hole. The substrate is attached to an optical box that is to store the deflector. The detection unit detects the laser light to control an irradiation position on a scanned surface of the laser light reflected by the deflector. The optical box is provided with a passing portion to guide the laser light emitted from the light source to the detection unit, and protruded portions disposed around the passing portion and protruded toward the substrate side. The substrate is attached to the optical box in a state where the protruded portions are engaged with walls forming the through-hole.

An optical scanning apparatus, an image projecting apparatus, and a mobile object. The optical scanning apparatus includes a light source to emit light, a light deflector to deflect the light emitted from the light source at least in a sub-scanning direction to perform optical scanning on a scan region, a light receiver to receive, within a predetermined range in the sub-scanning direction, the light used for optical scanning performed by the light deflector, and a controller to control the light deflector based on a number of times of light reception of the light receiver at a plurality of positions in the sub-scanning direction within the predetermined range. The image projecting apparatus includes the optical scanning apparatus, and a projection optical system configured to project light emitted from the optical scanning apparatus to the scan region.

A head-mounted display (HMD) is provided, including the following: an emitter configured to emit a scanning beam into an interactive environment in which the HMD is disposed, the scanning beam being configured to continuously trace a predefined scan pattern; a detector configured to detect reflections of the scanning beam back to the HMD by each of a plurality of reflectors; a processor configured to, for each reflector, determine a time at which the reflection of the scanning beam by the reflector occurred, wherein the time is used to determine a location or orientation of the HMD in the interactive environment; a display device configured to render a view of a virtual space that is determined based on the determined location or orientation of the HMD.