Image Forming Apparatus Isolated Pixel Correction
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Solution Overview
Problem
Image forming apparatuses without scanning lenses having the fθ characteristic face challenges in maintaining image quality due to variations in scanning speed and exposure, which affect the reproducibility of isolated pixels.
Innovation Solution
The apparatus includes a photosensitive member, an exposure unit that divides pixels into pieces for exposure, a determination unit to identify isolated pixels, a selection unit to choose correction target pixels from surrounding blank pixels, and a correction unit to adjust image data for exposure, enabling partial magnification and luminance corrections to ensure consistent image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a scanning lens having the fθ characteristic is used, then appropriate exposure with constant image quality is achieved, but the apparatus size and cost increase
Solution Approach 1:
The patent removes the scanning lens from the optical path, extracting the component that causes size and cost increases while maintaining image quality through alternative correction methods. The fθ characteristic is achieved without requiring a dedicated scanning lens by using software-based correction algorithms.
Solution Approach 2:
The patent replaces the mechanical/optical solution (scanning lens with fθ characteristic) with an information processing solution (software correction algorithms). Instead of using hardware to achieve constant scanning speed, the system uses image processing to correct variations in scanning speed and exposure after they occur.
2Device complexity
If a scanning lens without the fθ characteristic is used, then apparatus size and cost are reduced, but isolated pixel reproducibility deteriorates
Solution Approach 1:
The patent implements feedback correction by detecting isolated pixels and their surrounding blank pixels, then using this information to adjust the image data. The system identifies where pixels should be exposed and corrects the exposure variations through iterative processing, ensuring consistent isolated pixel reproduction despite the absence of fθ characteristic.
Solution Approach 2:
The patent changes the parameters of the image data based on detected pixel patterns. By analyzing the surroundings of isolated pixels and adjusting exposure parameters locally, the system compensates for scanning speed variations and maintains consistent pixel reproduction across different positions in the image.
3Manufacturing precision
If electrical correction is performed to maintain image quality, then isolated pixel reproducibility is improved, but processing time and complexity increase
Solution Approach 1:
The patent performs preliminary detection of isolated pixels and identification of correction targets before the main correction process. By pre-identifying which pixels need correction and planning the correction sequence in advance, the system reduces overall processing time while maintaining correction effectiveness.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution allows for the reduction of apparatus size and cost while maintaining image quality by correcting partial magnification and luminance variations, ensuring that isolated pixels are correctly exposed and reproduced across different image heights.
Implementation Method 1
an optical scanning device for exposing a photosensitive member. The optical scanning device causes a light beam to be reflected by a rotating polygon mirror to scan the surface of the photosensitive member, thus forming an electrostatic latent image on the photosensitive member
Data Source
AI summary
An image forming apparatus includes: a photosensitive member; an exposure unit configured to divide one pixel into a plurality of pixel pieces and perform exposure on a pixel piece-by-pixel piece basis, to form an electrostatic latent image on the photosensitive member; a determination unit configured to determine, based on image data, an isolated pixel surrounded by blank pixels in the electrostatic latent image; a selection unit configured to select a correction target pixel from the blank pixels surrounding the isolated pixel; and a correction unit configured to correct the image data so as to expose a pixel piece of the correction target pixel.