Charging Roller Elastic Layer Vibration Suppression
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Solution Overview
Problem
Existing charging members in electrophotographic apparatuses fail to effectively suppress the formation of banding images caused by vibration of photosensitive members over a long period, leading to unstable and low-quality image formation.
Innovation Solution
A charging member with an elastic layer containing a rubber having a polar group and hollow particles with a shell made of calcium carbonate crystals, which enhances vibration absorption and restoration, stabilizing contact between the charging member and the photosensitive member.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If an electroconductive foam elastic layer is used to suppress vibration influence, then the charging roller can reduce vibration impact, but the foamed cells cannot restore sufficiently after deformation, causing banding images to appear in the latter half of durability time
Solution Approach 1:
The patent combines rubber particles with specific physical properties (softness, elasticity, hysteresis loss characteristics) with electroconductive material to create a composite elastic layer. This composite structure provides both vibration absorption capability and sustained performance over time, resolving the contradiction between initial vibration suppression and long-term reliability.
Solution Approach 2:
The patent specifies precise parameter ranges for the rubber particles including softness (50° to 90° on Shore A scale), particle size (0.1 mm to 5.0 mm), and hysteresis loss tangent (0.05 to 0.20). By optimizing these parameters, the elastic layer achieves optimal balance between vibration absorption and restoration capability, preventing banding images during extended operation.
2Stability of the object's composition
If inorganic balloons with high elasticity are used in the elastic layer, then rapid restoration after deformation is achieved, but the suppressing effect on vibration is insufficient
Solution Approach 1:
The patent identifies the tangent of hysteresis loss as a critical parameter range (0.05 to 0.20) that balances restoration speed and vibration suppression. Rubber particles within this range restore sufficiently fast while maintaining adequate vibration damping, unlike inorganic balloons that restore too quickly with insufficient vibration suppression.
Solution Approach 2:
The use of porous rubber particles provides both the necessary elasticity for restoration and the structural characteristics for vibration absorption. The porous structure allows the material to deform and restore while dissipating vibration energy, achieving a balance that solid inorganic balloons cannot provide.
3Productivity
If high-speed drive is implemented to increase productivity, then the electrophotographic apparatus operates faster, but the photosensitive member vibration increases causing unstable contact and non-uniform charging
Solution Approach 1:
The patent converts the harmful effect of vibration into a beneficial one by selecting rubber particles with specific hysteresis loss characteristics. The vibration that would normally cause instability is instead absorbed and dissipated as heat through the rubber particles' hysteresis loss, allowing high-speed operation to proceed with maintained charging 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 suppresses banding image formation by efficiently absorbing and restoring vibration, ensuring stable and high-quality electrophotographic image formation over an extended period.
Implementation Method 1
the inorganic balloon has elasticity higher than that of the foamed cells of Japanese Patent Application Laid-Open No. 2004-279578. Therefore, the inorganic balloon is restored rapidly after being deformed, but the suppressing effect on the vibration is not sufficient
Implementation Method 2
the elastic layer contains a rubber having a polar group and a hollow particle having a shell containing a crystal of calcium carbonate
Data Source
AI summary
Provided is a charging member for suppressing the vibration of a charging roller which occurs owing to a difference in circumferential speed in a longitudinal direction when the roller is rotated to follow a photosensitive member, and suppressing a banding image caused by the vibration of the charging roller over a long period of time. The charging member includes a substrate and an elastic layer. The elastic layer contains a rubber having a polar group and hollow particles each having a shell containing a crystal of calcium carbonate.