Image Forming Apparatus Bow Correction Density Smoothing
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Solution Overview
Problem
Existing image forming apparatuses face issues with reciprocity failure leading to image density unevenness, particularly during electronic bow correction, where streak images and density level differences occur due to the complexity of driving systems and high costs associated with multi-beam scanning, and synchronization challenges between density correction and bow correction.
Innovation Solution
An electrophotographic image forming apparatus that performs electronic bow correction using a bow corrector and density smoothing processor to match image data with the bow characteristic of black, and employs a density correction processor for light intensity correction to prevent streak images and density unevenness, utilizing a grayscale cycle of a dither pattern for processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If electronic bow correction is performed to correct image position deviation, then color misregistration is suppressed, but streak images and density unevenness occur at the boundary of bow correction
Solution Approach 1:
The patent applies preliminary action by performing density smoothing processing on image data before it is subjected to bow correction. The density smoothing processor pre-processes the image data to prevent density unevenness from occurring in the first place, rather than attempting to correct it after bow correction creates the problem. This anticipatory approach eliminates streak images at bow correction boundaries while maintaining the position correction functionality.
2Manufacturing precision
If multi-beam scanning is used to cope with reciprocity failure, then image density unevenness is reduced, but the driving system becomes complicated and cost increases
Solution Approach 1:
The patent uses copying by creating a density smoothing map that replicates the ideal density distribution pattern across the image. Instead of using multiple physical light beams, the system generates a digital copy of the correction pattern and applies it through image processing. This virtual copying approach achieves density uniformity without the mechanical complexity of multi-beam scanning systems.
3Manufacturing precision
If density correction is performed to correct reciprocity failure, then image density uniformity is improved, but synchronization with bow correction becomes difficult and streak images occur
Solution Approach 1:
The patent merges the density correction function with the bow correction process by integrating the density smoothing processor into the existing image processing pipeline. The density smoothing is combined with the bow correction operations rather than being performed as a separate, synchronized step. This merging eliminates synchronization issues while achieving both position correction and density uniformity.
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
The solution effectively prevents streak images and density unevenness by reducing the calculation load of density correction and maintaining smooth density changes, ensuring excellent image quality without increasing processing complexity or cost.
Implementation Method 1
a light beam emitted from a light source, such as a semiconductor laser
Implementation Method 2
focused on a photoconductor drum (image carrier) by a scanning optical system to form an electrostatic latent image
Data Source
AI summary
An electrophotographic image forming apparatus that scans a surface of an image carrier with multiple beams emitted from a plurality of light emitting elements on a basis of image data of multiple colors including black comprises a bow corrector that performs electronic bow correction of image data of a predetermined color other than black in accordance with a bow characteristic of black; and a density smoothing processor that smoothens a density level difference of an image of the predetermined color subjected to the bow correction by a density smoothing process.