Dynamic Pixel Division for Magnification Correction
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Solution Overview
Problem
Existing image forming apparatuses face challenges in performing magnification correction without an fθ lens or with an fθ lens of low accuracy, leading to increased hardware scale and reduction in image quality due to quantization errors and varying scanning speeds.
Innovation Solution
An image forming apparatus that includes a photosensitive member, an exposure unit, a generation unit for dividing pixels, a calculation unit to determine ideal division numbers based on pixel positions, and a determination unit that adjusts division numbers using feedback to minimize quantization errors and maintain image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If magnification correction is performed by dividing pixels and using interpolation processing, then image quality degradation is suppressed, but hardware scale increases due to memory requirements for storing magnification information for each pixel
Solution Approach 1:
The patent changes the parameter of pixel division by dynamically adjusting the division number based on image height rather than using a fixed division number. This allows the system to adapt to varying magnification requirements across different regions of the photosensitive member, maintaining image quality without requiring complex per-pixel correction tables
Solution Approach 2:
The patent introduces dynamic adjustment of the pixel division number based on image height. The determination unit changes the division number according to the vertical position on the photosensitive member, creating a dynamic correction system that replaces static per-pixel correction tables, thereby reducing hardware requirements while maintaining correction accuracy
2Ease of manufacture
If an optical structure without fθ lens is used to reduce cost, then manufacturing cost decreases, but scanning speed becomes non-uniform and magnification correction becomes difficult
Solution Approach 1:
The patent replaces the optical correction mechanism (fθ lens) with an electronic/image processing mechanism. By using dynamic pixel division and interpolation processing based on image height, the system achieves magnification correction through computational methods rather than optical components, eliminating the need for expensive precision optics while maintaining correction accuracy
Solution Approach 2:
The patent compensates for the non-uniform scanning characteristics of lens-less optical systems by dynamically changing the pixel division parameter based on image height. This allows the image processing system to counteract the varying magnification effects, achieving uniform image quality without requiring uniform optical scanning
3Adaptability or versatility
If pixel division is used for magnification correction, then magnification can be adjusted, but quantization errors increase and reduce image quality
Solution Approach 1:
The patent dynamically adjusts the pixel division number based on image height rather than using a fixed division number. This dynamic approach allows the system to optimize the balance between magnification adjustment capability and quantization error minimization for each region, improving overall image quality while maintaining magnification versatility
Solution Approach 2:
The determination unit uses feedback from the ideal division number calculation to adjust the actual pixel division. By comparing the calculated ideal division with the actual division and using this feedback to optimize interpolation processing, the system minimizes quantization errors while maintaining the ability to adjust magnification
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 enables magnification correction without increasing hardware scale, preventing reduction in image quality caused by quantization errors and maintaining consistent scanning characteristics across the photosensitive member.
Implementation Method 1
an image is formed by forming an electrostatic latent image on a photosensitive member through control of laser in accordance with an image signal
Implementation Method 2
a laser beam radiated to the photosensitive member is deflected with a rotation of a rotary polygon mirror
Implementation Method 3
the laser beam is radiated to the photosensitive member through an fθ lens to perform optical correction with the fθ lens. In other words, scanning characteristics of the laser beam, such as a scanning speed, an optical path length, and an angle of incidence in the longitudinal direction are uniformized by the fθ lens
Data Source
AI summary
An image forming apparatus including: a photosensitive member rotatable in a first direction; an exposure unit configured to scan the photosensitive member with a light beam in a second direction substantially orthogonal to the first direction to form a latent image; a generation unit configured to generate data corresponding to a gradation of a predetermined pixel of input image data by dividing the predetermined pixel by a predetermined division number; a calculation unit configured to calculate an ideal division number depending on a position of the predetermined pixel in the second direction; and a determination unit configured to determine the predetermined division number based on the ideal division number, wherein the determination unit feeds back an error between an ideal division number and a division number for a pixel at a position preceding the predetermined pixel in determining the predetermined division number for the predetermined pixel.