Abstract: A housing includes a body having an opening. The body includes a peripheral portion that abuts on the opening. A cover covers at least a part of the opening. A seal is sandwiched between the cover and the peripheral portion of the body. At least one of the cover and the peripheral portion of the body includes a corner portion and a linear portion. The corner portion has a first shape that defines one of a gap between the cover and the peripheral portion of the body and a width of the seal. The linear portion abuts on the corner portion. The linear portion has a second shape that defines the one of the gap between the cover and the peripheral portion of the body and the width of the seal. The second shape is different from the first shape of the corner portion.

Abstract: A casing structure, an optical scanner, and an image forming apparatus. The casing structure includes a casing having an opening, a cover that covers the opening of the casing, and a seal disposed between the casing and the cover. In the casing structure, the cover is openable and closable with respect to the casing, and the seal contacting the casing and the cover when the cover is closed. In the casing structure, the casing or the cover including at least one portion contained in the seal in a cross section taken in a direction the cover is opened or closed. The optical scanner includes the casing structure. In the optical scanner, the casing stores a plurality of components to be applied to an image forming apparatus, and the cover has an optical element through which light passes. The image forming apparatus includes the optical scanner.

Abstract: An optical scanning device includes light sources, a deflector, an optical element, and light blockers. The light blockers are spaced apart in a rotation direction of the deflector. An inequality ?1<?2 is satisfied, where when viewed from the rotation axis direction, ?1 is an angle formed by a line segment connecting the end portion of a light blocker disposed most downstream in the rotation direction to a rotation axis center of the deflector and a line segment connecting the end portion of a light blocker disposed most upstream in the rotation direction to the rotation axis center, and ?2 is an angle formed by a line segment connecting an upstream end portion of one mirror surface in the rotation direction to the rotation axis center and a line segment connecting a downstream end portion of the one mirror surface in the rotation direction to the rotation axis center.

Abstract: A housing includes a body having an opening. The body includes a peripheral portion that abuts on the opening. A cover covers at least a part of the opening. A seal is sandwiched between the cover and the peripheral portion of the body. At least one of the cover and the peripheral portion of the body includes a corner portion and a linear portion. The corner portion has a first shape that defines one of a gap between the cover and the peripheral portion of the body and a width of the seal. The linear portion abuts on the corner portion. The linear portion has a second shape that defines the one of the gap between the cover and the peripheral portion of the body and the width of the seal. The second shape is different from the first shape of the corner portion.

Abstract: An optical scanning device includes light sources, a deflector, an optical element, and light blockers. The light blockers are spaced apart in a rotation direction of the deflector. An inequality ?1<?2 is satisfied, where when viewed from the rotation axis direction, ?1 is an angle formed by a line segment connecting the end portion of a light blocker disposed most downstream in the rotation direction to a rotation axis center of the deflector and a line segment connecting the end portion of a light blocker disposed most upstream in the rotation direction to the rotation axis center, and ?2 is an angle formed by a line segment connecting an upstream end portion of one mirror surface in the rotation direction to the rotation axis center and a line segment connecting a downstream end portion of the one mirror surface in the rotation direction to the rotation axis center.

Abstract: An image forming apparatus includes circuitry, a reader, and an exposure device that drives lighting elements aligned in a main scanning direction to form a first test image. The circuitry acquires density of first sub-areas, into which the first test image is divided in the main scanning direction, and calculates first correction data based on density of each of the first sub-areas and average density of the first sub-areas, to correct light amounts of the lighting elements. The exposure device forms a second test image with the light amounts corrected. The circuitry acquires density of second sub-areas, into which the second test image is divided in the main scanning direction, and calculates second correction data based on density of a second sub-area adjacent to each of the second sub-areas, to further correct the light amounts. The second sub-areas are differently located from the first sub-areas in the main scanning direction.

Abstract: An image forming apparatus includes a latent image bearer, a latent image writing device, a developing device, a conveyance unit to convey a recording medium, a transfer device, a length data acquisition unit to obtain a length of the recording medium in a conveyance direction of the recording medium, an image forming processor to form a test pattern, and a light quantity correction calculator that acquires image density data of the test pattern and calculates a light quantity correction value to correct a light quantity. The image forming processor sets a position of the test pattern on the recording medium in the conveyance direction of the recording medium and a length of the test pattern in the conveyance direction of the recording medium based on the length of the recording medium in the conveyance direction of the recording medium obtained by the length data acquisition unit.

Abstract: An image forming apparatus includes an image reading device; an image forming device including a photoconductor, a charger, an exposure device including a light-emitting element, a memory to store a first correction value for correction a light emission amount of the light-emitting element, and a driver to drive the light-emitting element, a developing device, a transfer device, and a fixing device. The image forming apparatus further includes a processor to calculate a second correction value for correcting the light emission amount, based on density data of image data of a predetermined pattern on a recording medium; calculate a third correction value for correcting the light emission amount, based on the first correction value and the second correction value; and determine, before calculating the third correction value, whether placement of the recording medium on the reading table is correct based on the density data.

Abstract: An image forming apparatus includes circuitry, a reader, and an exposure device that drives lighting elements aligned in a main scanning direction to form a first test image. The circuitry acquires density of first sub-areas, into which the first test image is divided in the main scanning direction, and calculates first correction data based on density of each of the first sub-areas and average density of the first sub-areas, to correct light amounts of the lighting elements. The exposure device forms a second test image with the light amounts corrected. The circuitry acquires density of second sub-areas, into which the second test image is divided in the main scanning direction, and calculates second correction data based on density of a second sub-area adjacent to each of the second sub-areas, to further correct the light amounts. The second sub-areas are differently located from the first sub-areas in the main scanning direction.

Abstract: An optical scanner includes a light source including a plurality of light emitting elements, a polygon mirror which deflects light from the light source for scanning a surface of a subject, an optical element arranged between the light source and the polygon mirror, having optical power in a sub scanning direction, a synchronous detector which detects the light deflected by the polygon mirror for synchronous detection and generates a signal for controlling a timing at which the scanning of the surface is started, and a fixing element which secures one end of the optical element. The light emitting elements of the light source are aligned with a certain tilt angle relative to the sub scanning direction. Light from one of the light emitting elements disposed closest to the fixing element in a main scanning direction is used for synchronous detection.

Abstract: An image forming apparatus includes an image reading device; an image forming device including a photoconductor, a charger, an exposure device including a light-emitting element, a memory to store a first correction value for correction a light emission amount of the light-emitting element, and a driver to drive the light-emitting element, a developing device, a transfer device, and a fixing device. The image forming apparatus further includes a processor to calculate a second correction value for correcting the light emission amount, based on density data of image data of a predetermined pattern on a recording medium; calculate a third correction value for correcting the light emission amount, based on the first correction value and the second correction value; and determine, before calculating the third correction value, whether placement of the recording medium on the reading table is correct based on the density data.

Abstract: An image forming apparatus includes a latent image bearer, a latent image writing device, a developing device, a conveyance unit to convey a recording medium, a transfer device, a length data acquisition unit to obtain a length of the recording medium in a conveyance direction of the recording medium, an image forming processor to form a test pattern, and a light quantity correction calculator that acquires image density data of the test pattern and calculates a light quantity correction value to correct a light quantity. The image forming processor sets a position of the test pattern on the recording medium in the conveyance direction of the recording medium and a length of the test pattern in the conveyance direction of the recording medium based on the length of the recording medium in the conveyance direction of the recording medium obtained by the length data acquisition unit.

Abstract: An image forming apparatus includes an image bearer, an exposure device, a drive device, a cleaning body, and an exposure device holder. The exposure device is disposed on a motion trajectory between an exposure position and a retracted position and emits light to the image bearer via a lens having a lens surface at the exposure position. The drive device causes the exposure device to move between the exposure position and the retracted position. The cleaning body disposed on the motion trajectory of the exposure device tilts a cleaning surface when contacting with the lens surface of the exposure device. The exposure device holder supports the exposure device while changing an attitude of the exposure device such that the lens surface remains in contact with the cleaning surface of the cleaning body when the exposure device moves from the retracted position to the exposure position.

Abstract: An optical scanner includes a light source including a plurality of light emitting elements, a polygon mirror which deflects light from the light source for scanning a surface of a subject, an optical element arranged between the light source and the polygon mirror, having optical power in a sub scanning direction, a synchronous detector which detects the light deflected by the polygon mirror for synchronous detection and generates a signal for controlling a timing at which the scanning of the surface is started, and a fixing element which secures one end of the optical element. The light emitting elements of the light source are aligned with a certain tilt angle relative to the sub scanning direction. Light from one of the light emitting elements disposed closest to the fixing element in a main scanning direction is used for synchronous detection.

Abstract: An optical scanner includes a light source including a plurality of light emitting elements, a polygon mirror which deflects light from the light source for scanning a surface of a subject, an optical element arranged between the light source and the polygon mirror, having optical power in a sub scanning direction, a synchronous detector which detects the light deflected by the polygon mirror for synchronous detection and generates a signal for controlling a timing at which the scanning of the surface is started, and a fixing element which secures one end of the optical element. The light emitting elements of the light source are aligned with a certain tilt angle relative to the sub scanning direction. Light from one of the light emitting elements disposed closest to the fixing element in a main scanning direction is used for synchronous detection.

Abstract: An image forming apparatus includes an image bearer, an exposure device, a (hive device, a cleaning body, and an exposure device holder. The exposure device is disposed on a motion trajectory between an exposure position and a retracted position and emits light to the image bearer via a lens having a lens surface at the exposure position. The drive device causes the exposure device to move between the exposure position and the retracted position. The cleaning body disposed on the motion trajectory of the exposure device tilts a cleaning surface when contacting with the lens surface of the exposure device. The exposure device holder supports the exposure device while changing an attitude of the exposure device such that the lens surface remains in contact with the cleaning surface of the cleaning body when the exposure device moves from the retracted position to the exposure position.

Abstract: In a light beam scanning device, a plurality of light sources, which irradiates a plurality of light beams in a first direction and is retained by a holder, are disposed at distance from one another in a second direction orthogonal to the first direction. The plurality of light beams are incident, via a coupling optical system, to deflecting and reflecting surfaces of a deflector from a direction that is tilted with respect to a plane orthogonal to the rotational shaft of the deflector. The holder is supported by a housing of the light beam scanning device at a plurality of different positions in a third direction extending from the light source to the coupling optical system.

Abstract: An optical scanning device includes a light source configured to emit a light beam; a rotary deflector configured to perform optical scanning by reflecting and deflecting the light beam emitted from the light source while rotating; an optical system forming member configured to form a path of the light beam; and a resonator having a resonance frequency corresponding to a sound generated by rotational drive of the rotary deflector. The rotary deflector is installed in a closed space. The resonator is installed so that the sound within the closed space is absorbed.

Abstract: An optical scanning device includes a light source configured to emit a light beam; a rotary deflector configured to perform optical scanning by reflecting and deflecting the light beam emitted from the light source while rotating; an optical system forming member configured to form a path of the light beam; and a resonator having a resonance frequency corresponding to a sound generated by rotational drive of the rotary deflector. The rotary deflector is installed in a closed space. The resonator is installed so that the sound within the closed space is absorbed.

Abstract: An optical scanning device that performs optical scanning across an object to be scanned with a light deflected, comprises: a deflection unit that causes a deflection mirror driven by a driving source to deflect the travel direction of light emitted from a light source and generates the light deflected; a resonator that includes a resonance space for reducing sound emitted from the deflection unit and a resonance passage communicating with the resonance space to direct sound from outside to inside the resonance space; a housing that accommodates the deflection unit and the resonator, and a partition wall that partitions a deflection unit accommodating space acting as a space for accommodating the deflection unit in the housing and a resonator accommodating space acting as a space for accommodating the resonator in the housing.