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US 9,703,230 B2Granted
Image forming apparatus correcting unevenness of potential distribution due to change of exposure spot shape of light beam on photosensitive member
AssigneeCanon Kabushiki Kaisha
InventorsIzuru Horiuchi, Yoichi Takikawa, Jun Hirabayashi
Life of this patent
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Abstract
An incidence angle of laser light with respect to a photosensitive member in a main-scanning direction is different depending on an exposure position. Hence, the spot shape of the laser light on the photosensitive member is different in the main-scanning direction. A filter coefficient is changed in the main-scanning direction, and image data is corrected with the filter coefficient.
Claims9
An image forming apparatus, comprising:
- a light source configured to emit light beam for exposing a photosensitive member to light;
- a deflecting unit configured to deflect the light beam so that the light beam scans the photosensitive member;
- an optical unit configured to guide the light beam deflected by the deflecting unit to the photosensitive member;
- a data generating unit configured to generate pixel data corresponding to each pixel included in an output image;
- an outputting unit configured to output correction data for correcting unevenness of a potential distribution of an electrostatic latent image centered at a target pixel formed on the photosensitive member due to a change of an exposure spot shape of the light beam on the photosensitive member in a scanning direction in which the light beam scans the photosensitive member,
- wherein the outputting unit outputs the correction data for pixel data of the target pixel based on pixel data of surrounding pixels located around the target pixel, the correction data being set for each of a plurality of regions of the photosensitive member in the scanning direction, the outputting unit switching the correction data outputted depending on the position of the target pixel in the scanning direction;
- a correcting unit configured to correct pixel data of the target pixel on the basis of the correction data and the pixel data of the surrounding pixels;
- and
- a control unit configured to control the light source on the basis of the pixel data of the target pixel corrected by the correcting unit, to form the target pixel.
6 more elements
An image forming apparatus, comprising:
- a light source configured to emit light beam for exposing a photosensitive member to light;
- a deflecting unit configured to deflect the light beam so that the light beam scans the photosensitive member;
- an optical unit configured to guide the light beam deflected by the deflecting unit to the photosensitive member;
- a data generating unit configured to generate pixel data corresponding to each pixel included in an output image;
- an outputting unit configured to output correction data for correcting unevenness of a potential distribution of an electrostatic latent image centered at a target pixel formed on the photosensitive member due to a change of an exposure spot shape of the light beam on the photosensitive member in a scanning direction in which the light beam scans the photosensitive member, the correction data being indicative of an amount of change in potential at a pixel position of surrounding pixels surrounding the target pixel caused by exposure of the target pixel to the light beam, the correction data being set for each of a plurality of regions of the photosensitive member in the scanning direction, the outputting unit switching the correction data outputted depending on the position of the target pixel in the scanning direction;
- a correcting unit configured to correct pixel data of the target pixel corrected on the basis of the correction data and the pixel data of the surrounding pixels;
- and
- a control unit configured to control the light source on the basis of the pixel data corrected by the correction unit, to form the target pixel.
5 more elements
Dependencies are inferred from the claim text.