A housing of an optical scanning device includes a first abutting portion and a second abutting portion. In the optical scanning device, an optical axis adjustment and a focal position adjustment in a main scanning direction and a sub scanning direction are conducted in a state where a part of a holder that holds a light source unit for emitting multi-beam light abuts on the first abutting portion and in a state where a part of a peripheral edge of an optical element that has both a collimator lens function and a cylindrical lens function abuts on the second abutting portion. Furthermore, a beam pitch of the multi-beam light is adjusted by rotating the holder around an optical axis in a state where the holder abuts on the first abutting portion.

An optical writing device and an image forming apparatus incorporating the optical writing device. The optical writing device includes two or more light sources, a pixel clock generator to measure a scanning speed of one of the two or more light sources and generate a pixel clock of a cycle corrected according to the measured scanning speed, a pulse data generation and output unit to generate pulse width data and shift data for the pixel clock generated by the pixel clock generator to output the generated pulse width data and the generated shift data for each one of the two or more light sources, and a plurality of image pulse generation and output units to generate an image pulse. In the optical writing device, the plurality of image pulse generation and output units are supplied with the pixel clock in common.

An optical writing device and an image forming apparatus incorporating the optical writing device. The optical writing device includes two or more light sources, a pixel clock generator to measure a scanning speed of one of the two or more light sources and generate a pixel clock of a cycle corrected according to the measured scanning speed, a pulse data generation and output unit to generate pulse width data and shift data for the pixel clock generated by the pixel clock generator to output the generated pulse width data and the generated shift data for each one of the two or more light sources, and a plurality of image pulse generation and output units to generate an image pulse. In the optical writing device, the plurality of image pulse generation and output units are supplied with the pixel clock in common.

An optical scanning device is provided with a housing, a plurality of laser light sources, and a substrate. The laser light sources are attached to a side wall of the housing in a state wherein three terminals are protruding outward. The substrate is disposed to face an outer surface of the side wall of the housing. The laser light sources include: a first laser light source having a predetermined angle with respect to the substrate; and a second laser light source having a symmetrical angle to the angle of the first laser light source with respect to the substrate. In the first laser light source, only one of the three terminals is bent in the direction to be separated from other two terminals, and the second laser light source is disposed by inverting 180° a laser light source having a configuration same as that of the first laser light source.

An optical scanning device is provided with a housing, a plurality of laser light sources, and a substrate. The laser light sources are attached to a side wall of the housing in a state wherein three terminals are protruding outward. The substrate is disposed to face an outer surface of the side wall of the housing. The laser light sources include: a first laser light source having a predetermined angle with respect to the substrate; and a second laser light source having a symmetrical angle to the angle of the first laser light source with respect to the substrate. In the first laser light source, only one of the three terminals is bent in the direction to be separated from other two terminals, and the second laser light source is disposed by inverting 180° a laser light source having a configuration same as that of the first laser light source.

An exposure device includes: a first light emitting element; a first lens array that converges light emitted from the first light emitting element; a second light emitting element; a second lens array that converges light emitted from the second light emitting element; a holder that holds the first light emitting element, the first lens array, the second light emitting element, and the second lens array; and a first adjustment mechanism that is provided in the holder and adjusts a first distance between the first lens array and the first light emitting element.

An exposure device includes: a first light emitting element; a first lens array that converges light emitted from the first light emitting element; a second light emitting element; a second lens array that converges light emitted from the second light emitting element; a holder that holds the first light emitting element, the first lens array, the second light emitting element, and the second lens array; and a first adjustment mechanism that is provided in the holder and adjusts a first distance between the first lens array and the first light emitting element.

An image forming apparatus, including: a light source including a plurality of light emitting points and configured to emit light beams; a photosensitive member configured to rotate in a rotation direction so that a latent image is formed thereon with the light beams; a rotary polygon mirror configured to rotate around a rotation axis and having a plurality of mirror faces each configured to deflect the light beams so that the photosensitive member is scanned with the light beams; a detector configured to detect temperature; and a correction unit configured to correct image data of an input image by using a deviation amount, in the rotation direction of the photosensitive member, of the light beams deflected by each of the plurality of mirror faces, wherein the correction unit obtains the deviation amount according to the temperature detected by the detector.

An image forming apparatus, including: a light source including a plurality of light emitting points and configured to emit light beams; a photosensitive member configured to rotate in a rotation direction so that a latent image is formed thereon with the light beams; a rotary polygon mirror configured to rotate around a rotation axis and having a plurality of mirror faces each configured to deflect the light beams so that the photosensitive member is scanned with the light beams; a detector configured to detect temperature; and a correction unit configured to correct image data of an input image by using a deviation amount, in the rotation direction of the photosensitive member, of the light beams deflected by each of the plurality of mirror faces, wherein the correction unit obtains the deviation amount according to the temperature detected by the detector.

A positional deviation correction pattern includes a first and second pattern image portions adjacent in a sub-scanning direction at the same position in a main-scanning direction, with the same width in the main-scanning direction. Each image portion includes a first side extending in the sub-scanning direction, a second side continuing from one end of the first side and extending in a direction intersecting the sub-scanning direction, and a third side continuing from the other end and extending in a direction intersecting both the sub-scanning direction and the second side. The second sides have the same inclination angle to a virtual line parallel to the main-scanning direction. The third sides have the same inclination angle to the virtual line. A length of one image portion in the sub-scanning direction gradually increases from one end to the other end in the main-scanning direction, a length of the other image portion gradually decreases.