A light scanning unit includes a plurality of light source portions to emit modulated light beams intermittently according to image information of an image forming job while the image forming job is performed, and a plurality of polygonal mirrors, having different numbers of deflection facets, to rotate at a same rotational speed while is image forming job is performed so that the modulated light beams are incident on a subset including at least one of the deflection facets of the plurality of polygonal mirrors that rotate and the subset including the at least one of the deflection facets deflects the modulated light beams incident thereon to scan an object to be exposed.

A CPU is provided which controls a first light emission state in which a light source is controlled to emit a light beam to scan a full-scanning region and a second light emission state in which the light source is controlled to emit a light beam to scan a non-image region in a period from start of activation of a scanning motor to when the number of rotations of the scanning motor reaches a target number of rotations. The CPU acquires BD cycle values of BD signals generated by a main-scanning synchronization sensor, determines a second timing for changing from the first light emission state to the second light emission state on the basis of the two serial BD cycle values, and changes the semiconductor laser from the first light emission state to the second light emission state according to the second timing.

An image forming apparatus has a light scanning apparatus which is capable of aligning a lens with a plurality of light-emitting devices and forming a high-quality image while suppressing generation of moiré. In a first image formation mode, light-emitting devices outputting light beams exposing both ends of the photosensitive member in a rotational direction and at least a part of light-emitting devices exposing an area between exposure positions of the light-emitting devices outputting the light beams exposing the both ends are used to form an electrostatic latent image on the photosensitive member. In a second image formation mode, the light-emitting devices outputting the light beams exposing both ends are not used, and at least a part of light-emitting devices exposing an area between exposure positions of the light-emitting devices outputting the light beams exposing both ends are used to form the electrostatic latent image on the photosensitive member.

The detector that detects a light beam emitted from a light source of a second image forming device and reflected by a polygon mirror, and an adjustment device that performs adjustment processing of adjusting the velocity of the polygon mirror based on an output of the detector are provided. Before a first image forming device performs the image forming processing, the adjustment device performs the adjustment processing while causing the light source of the second image forming device to emit the light beam during a time period including at least a time period in which a photosensitive member of the second image forming device is emitted with the light beam. Before the adjustment processing is finished, the first image forming device starts to move a developing member to a developing position.

A system, article, and method to provide lens shading color correction using block matching.

An example laser assembly for a laser printer may include a plurality of lasers to emit respective photons; a prism to redirect the respective laser beams emitted from the plurality of lasers toward a collimator lens of the laser printer to generate a photon beam; and one or more processors to: determine a timing schedule for individually activating the plurality of lasers based on a resolution setting of the laser printer, and when printing at a resolution corresponding to the resolution setting, control activation of each of the plurality of lasers to emit the respective photons according to the timing schedule to form the photon beam.

An image forming apparatus includes a first medium scanned with a first signal, a second medium scanned with a second signal, a rotary polygon mirror that deflects the first and second signals, a synchronization signal generation circuit that generates a synchronization signal representing a time to start scanning the first medium, and at least one pseudo synchronization signal generation circuit that generates a pseudo synchronization signal with the synchronization signal. The pseudo synchronization signal represents a time to start scanning the second medium. Based on a previously calculated period of the synchronization signal and a period of the synchronization signal counted on a particular surface of the polygon mirror, the pseudo synchronization signal generation circuit generates a particular value for generating the pseudo synchronization signal. Based on the particular value, the pseudo synchronization signal generation circuit starts generating the pseudo synchronization signal when the synchronization signal is enabled.

Systems, articles and methods to provide lens shading color correction using block matching are disclosed. Example processor systems disclosed herein are to process at least one cluster of blocks of an image to determine at least one modification parameter, modify the first shade correction data based on the at least one modification parameter to determine second shade correction data, and correct a lens shade effect associated with the image based on the second shade correction data.

A pattern forming apparatus for forming a pattern by emitting a scanning light onto a plurality of base materials conveyed in a predetermined conveying direction, includes a plurality of emitting units including a first emitting unit and a second emitting unit. The first emitting unit includes a first light source unit to emit a first laser light; a first conveying direction light scanning unit to scan the first laser light in the predetermined conveying direction; a first intersecting direction light scanning unit to scan a scanning light, scanned by the first conveying direction light scanning unit, in an intersecting direction that intersects the predetermined conveying direction. Further, there is a first light emitting unit to emit a first scanning light, scanned by the first intersecting direction light scanning unit, onto a base material among the plurality of base materials.

Optical scanner and electrophotographic image forming device are provided. The optical scanner includes a light source; and a first optical unit, a deflection apparatus, and an f-θ lens, which are sequentially arranged along a primary optical axis direction of a light beam emitted from the light source. The light beam emitted from the light source is focused onto a scanning target surface after sequentially passing through the first optical unit, the deflection apparatus, and the f-θ lens. Optical scanning directions of the light beam emitted from the light source include a primary scanning direction and a secondary scanning direction which are perpendicular to each other, and along the primary scanning direction, the f-θ lens satisfies following expressions: SAG1>0, SAG2>0, and 0<(SAG1+SAG2)/d<0.8.