Image Magnification Correction Using Pseudorandom Bit Dispersion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional image forming apparatuses with optical scanning devices lacking a scanning lens or using inexpensive lenses face challenges in achieving high-quality imaging due to magnification errors and the generation of moire patterns during magnification correction in the main scanning direction.
Innovation Solution
An image forming apparatus that includes a photosensitive member, a laser light source, a deflection unit, a developing unit, a data conversion unit, a setting unit, a correction unit, and a driving unit, which converts a bit pattern to correct image magnification by adding bit data based on pseudorandom numbers to disperse correction pixels, thereby reducing moire patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a scanning lens is omitted or an inexpensive lens is used to reduce device cost, then device complexity and cost are reduced, but image magnification accuracy deteriorates
Solution Approach 1:
The patent replaces the optical lens (mechanical/optical component) with a digital correction method. Instead of using a scanning lens to control beam focus and magnification, the system uses digital signal processing to correct magnification variations. The correction unit adjusts the number of bit data pieces dynamically based on scanning position, substituting optical precision requirements with digital control capabilities.
Solution Approach 2:
The patent changes the parameter of bit data quantity from fixed to variable. By dynamically adjusting the number of bit data pieces (N) based on the scanning position and corresponding magnification factor, the system compensates for optical deficiencies. This parameter change allows the same hardware to achieve consistent image quality across different scanning positions without requiring a expensive lens.
2Manufacturing precision
If magnification correction is applied to all pixels in the main scanning direction, then image magnification accuracy is improved, but moire pattern visibility increases
Solution Approach 1:
The patent applies different correction strategies to different regions of the image. Instead of uniformly correcting all pixels, it identifies and corrects only specific pixels where magnification errors occur. The correction unit determines the number of bit data pieces to add based on the scanning position, applying localized correction rather than global correction, thereby avoiding moire patterns while maintaining accuracy where needed.
Solution Approach 2:
The patent performs preliminary identification of pixels requiring correction before applying the correction. By pre-determining which pixels need magnification correction based on scanning position and magnification factors, the system can selectively apply corrections only where necessary, avoiding unnecessary corrections that would create moire patterns in regions where the original image data is already adequate.
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 corrects image magnification errors and minimizes the visibility of moire patterns, ensuring high-quality imaging while reducing the cost of optical scanning devices by eliminating the need for expensive lenses.
Implementation Method 1
a laser light source that emits a laser beam
Implementation Method 2
an optical scanning device that emits a laser beam for scanning a photosensitive member
Implementation Method 3
a deflection unit (e.g., rotatable polygon mirror) that deflects the laser beam emitted by the laser light source so as to scan the photosensitive member
Implementation Method 4
The laser beam deflected by the deflection unit is imaged on the photosensitive member through an optical lens, such as an f-theta (fθ) lens
Implementation Method 5
a developing unit that develops an electrostatic latent image formed on the photosensitive member upon the photosensitive member being scanned
Data Source
AI summary
By dispersing within an image magnified pixels subjected to magnification correction with the use of pseudorandom numbers, an occurrence of a moire pattern in an image is suppressed.