Charging Member Surface Profile for Image Density Control
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Solution Overview
Problem
Electrophotographic image forming apparatuses face issues with image density irregularities due to vibrations in the charging member, which affect the position of the latent image formation and the smooth transfer of toner images, resulting in density irregularities.
Innovation Solution
A charging member with a cylindrical, electroconductive base member and an elastic layer is designed, where the surface profile in the circumferential direction has a maximum amplitude within a specific range (0.20 μm to 0.90 μm in a period region of less than 5 mm), reducing vibrations and improving image stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the charging member has a smooth surface, then the image carrier can rotate smoothly, but vibrations occur causing image density irregularities
Solution Approach 1:
The patent applies local quality by creating a specific surface structure on the charging member with controlled irregularities (amplitude 0.05-2.0 μm, wavelength 0.5-5.0 mm) rather than a uniformly smooth surface. This localized surface modification allows the charging member to maintain good contact with the image carrier while reducing vibrations that cause density irregularities.
Solution Approach 2:
The patent changes the surface profile parameters of the charging member by controlling the amplitude and wavelength of surface irregularities within specific ranges. This parameter optimization resolves the contradiction by finding the optimal balance between smooth rotation and vibration reduction, improving image density uniformity.
2Stability of the object's composition
If the surface profile amplitude is increased to reduce vibrations, then image stability improves, but manufacturing precision requirements increase
Solution Approach 1:
The patent defines specific parameter ranges for surface profile (amplitude 0.05-2.0 μm, wavelength 0.5-5.0 mm) that balance vibration reduction with manufacturability. These controlled parameters achieve image stability while maintaining reasonable manufacturing precision requirements.
Solution Approach 2:
The patent applies partial action by introducing only the necessary amount of surface irregularity within controlled ranges, rather than creating excessive roughness. This partial modification is sufficient to reduce vibrations and improve image stability without over-complicating the manufacturing process.
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 controlled surface profile of the charging member reduces image density irregularities by minimizing vibrations from the charging member and other sources, ensuring consistent latent image formation and improved image quality.
Implementation Method 1
an elastic layer disposed on the outer circumferential surface of the electroconductive base member
Data Source
AI summary
A charging member includes a cylindrical, hollow or solid, electroconductive base member, and an elastic layer device disposed on the electroconductive base member. When a surface profile of the charging member is subjected to a periodicity analysis in a circumferential direction, the surface profile has a maximum amplitude, in a period region of smaller than 5 mm, within a range of higher than or equal to 0.20 μm and smaller than or equal to 0.90 μm.