An optical scanning device according to an embodiment includes a light source, a MEMS mirror, a MEMS-mirror driving unit, a control unit, and a sensor. The light source radiates a plurality of laser beams that scan a photoconductive drum. The MEMS mirror includes a reflection surface that reflects the plurality of laser beams radiated from the light source. The MEMS-mirror driving unit reciprocatingly moves the MEMS mirror. The sensor supplies a horizontal synchronization signal to the control unit by detecting the laser beam reflected on the reflection surface when the MEMS mirror reaches a predetermined position. After detecting the horizontal synchronization signal supplied from the sensor, the control unit performs the auto power control of the light amount of at least one laser beam among the plurality of laser beams.

An exposure unit comprises a polygon mirror configured to include a plurality of reflection surfaces; first to fourth light sources arranged at different angle positions along a rotation direction of the polygon mirror; two photo detectors configured to selectively detect first laser light and fourth laser light respectively at a scanning start end side of a main scanning direction among first to fourth laser light which are emitted from the respective light sources and reflected by the polygon mirror to be scanned in the main scanning direction; and a control section configured to control light emitting timing of the first to the fourth light sources on the basis of detection results of these photo detectors.

An exposure unit comprises a polygon mirror configured to include a plurality of reflection surfaces; first to fourth light sources arranged at different angle positions along a rotation direction of the polygon mirror; two photo detectors configured to selectively detect first laser light and fourth laser light respectively at a scanning start end side of a main scanning direction among first to fourth laser light which are emitted from the respective light sources and reflected by the polygon mirror to be scanned in the main scanning direction; and a control section configured to control light emitting timing of the first to the fourth light sources on the basis of detection results of these photo detectors.

According to one embodiment, there is provided a light emitting substrate which includes a transparent substrate, a plurality of light emitting element groups, and a control unit. The plurality of light emitting element groups are formed by overlapping a first light emitting element and a second light emitting element on the transparent substrate. The control unit controls light emitting of the first light emitting element and the second light emitting element of the plurality of light emitting element groups. Amounts of light emitted from the plurality of light emitting element groups are uniform.

An exposure unit comprises a polygon mirror configured to include a plurality of reflection surfaces; first to fourth light sources arranged at different angle positions along a rotation direction of the polygon mirror; two photo detectors configured to selectively detect first laser light and fourth laser light respectively at a scanning start end side of a main scanning direction among first to fourth laser light which are emitted from the respective light sources and reflected by the polygon mirror to be scanned in the main scanning direction; and a control section configured to control light emitting timing of the first to the fourth light sources on the basis of detection results of these photo detectors.

An exposure unit comprises a polygon mirror configured to include a plurality of reflection surfaces; first to fourth light sources arranged at different angle positions along a rotation direction of the polygon mirror; two photo detectors configured to selectively detect first laser light and fourth laser light respectively at a scanning start end side of a main scanning direction among first to fourth laser light which are emitted from the respective light sources and reflected by the polygon mirror to be scanned in the main scanning direction; and a control section configured to control light emitting timing of the first to the fourth light sources on the basis of detection results of these photo detectors.

An electric field sensor has a semiconductor stack, a first electrode, and a second electrode. The semiconductor stack includes a first semiconductor layer of a first conductive type and a second semiconductor layer of a conductive type opposite to the first conductive type stacked on the first semiconductor layer. The first electrode is arranged on one side of the semiconductor stack in the lamination direction. The second electrode is arranged on the other side of the semiconductor stack in the lamination direction. The electric field sensor detects the intensity of an electric field in the direction orthogonal to the lamination direction based on a current passing through the semiconductor stack.

An electric field sensor has a semiconductor stack, a first electrode, and a second electrode. The semiconductor stack includes a first semiconductor layer of a first conductive type and a second semiconductor layer of a conductive type opposite to the first conductive type stacked on the first semiconductor layer. The first electrode is arranged on one side of the semiconductor stack in the lamination direction. The second electrode is arranged on the other side of the semiconductor stack in the lamination direction. The electric field sensor detects the intensity of an electric field in the direction orthogonal to the lamination direction based on a current passing through the semiconductor stack.

An image processing apparatus includes: a first inverter to output binary image data having first resolution, as image data having pixel values that are inverted or image data having unprocessed pixel values, in accordance with an inversion signal; a thinning processor to convert the image data output from the first inverter from the first resolution to second resolution and perform a thinning process of thinning pixels of edge portions of the image data in units of the second resolution; and a second inverter to output the image data having the second resolution for which the thinning process is performed, as image data having pixel values that are inverted or image data having unprocessed pixel values, in accordance with the inversion signal.

An image processing apparatus includes: a first inverter to output binary image data having first resolution, as image data having pixel values that are inverted or image data having unprocessed pixel values, in accordance with an inversion signal; a thinning processor to convert the image data output from the first inverter from the first resolution to second resolution and perform a thinning process of thinning pixels of edge portions of the image data in units of the second resolution; and a second inverter to output the image data having the second resolution for which the thinning process is performed, as image data having pixel values that are inverted or image data having unprocessed pixel values, in accordance with the inversion signal.