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.

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.

An image recording apparatus includes: a laser emitting device configured to emit laser beams emitted from a plurality of laser light-emitting elements; an optical fiber array including a plurality of optical fibers provided corresponding to the laser light-emitting elements and configured to guide the laser beams emitted from the laser light-emitting elements to a recording object that relatively moves with respect to the laser emitting device, laser emitting portions of the respective optical fibers being arrayed in an array form in a predetermined direction; and an image recording unit configured to control the laser emitting device so as to irradiate the recording object which relatively moves with respect to the laser emitting device in a direction different from the predetermined direction, with laser beams via the optical fiber array, to heat the recording object and record an image.

An image forming apparatus includes an image forming device to form a correction image, an image density detector to detect image densities of a plurality of areas in the correction image, and circuitry to correct an image formation condition of the image forming device based on detected image densities of the plurality of areas. The circuitry replaces a detected image density of an area of interest selected from the plurality of areas with an average value of detected image densities of two or more areas including adjacent areas adjacent to the area of interest and corrects the image formation condition of the image forming device based on the detected image densities of the plurality of areas after replacement when a difference between the detected image density of the area of interest and at least one of the detected image densities of the adjacent areas exceeds a predetermined threshold.

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.

An image forming apparatus includes an image forming device to form a correction image, an image density detector to detect image densities of a plurality of areas in the correction image, and circuitry to correct an image formation condition of the image forming device based on detected image densities of the plurality of areas. The circuitry replaces a detected image density of an area of interest selected from the plurality of areas with an average value of detected image densities of two or more areas including adjacent areas adjacent to the area of interest and corrects the image formation condition of the image forming device based on the detected image densities of the plurality of areas after replacement when a difference between the detected image density of the area of interest and at least one of the detected image densities of the adjacent areas exceeds a predetermined threshold.

Systems, articles and methods to provide lens shading color correction using block matching are disclosed. Example processor systems disclosed herein include memory to store first shade correction data. Disclosed example processor systems also include processor circuitry to cluster blocks of an image into at least one cluster based on a criterion, process the at least one cluster to determine at least one modification parameter, modify the first shade correction data with 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.

An image forming apparatus includes an image forming device to form a correction image, an image density detector to detect image densities of a plurality of areas in the correction image, and circuitry to correct an image formation condition of the image forming device based on detected image densities of the plurality of areas. The circuitry replaces a detected image density of an area of interest selected from the plurality of areas with an average value of detected image densities of two or more areas including adjacent areas adjacent to the area of interest and corrects the image formation condition of the image forming device based on the detected image densities of the plurality of areas after replacement when a difference between the detected image density of the area of interest and at least one of the detected image densities of the adjacent areas exceeds a predetermined threshold.

A first receiving recess (44d) and a second receiving recess (44e) are formed on a surface of the housing, on which a pair of image forming lenses (47) are placed, to receive a first temperature sensor (101a) and a second temperature sensor (101b), and are formed in positions, in which thermal deformation characteristics of the housing are approximately identical at one side and the other side of a first straight line K1, while interposing the first straight line K1 therebetween.

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.