Charging Member Elastic Layer Hardness Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Charging members used in electrophotographic apparatuses face challenges in maintaining a uniform nip with photosensitive members while preventing compression set and toner adhesion, especially over long periods.
Innovation Solution
A charging member with an elastic layer having a specific hardness range (55° to 85° MD-1 hardness and 2.0 to 20.0 N/mm² universal hardness) is formed by vulcanizing a rubber composition and irradiating its surface with an electron beam, creating a higher cross-linking density on the surface for enhanced durability and flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a highly elastic material is used for the elastic layer to ensure flexibility and nip formation, then the flexibility is improved, but compression set occurs more easily
Solution Approach 1:
The patent applies parameter changes by precisely controlling the hardness of the elastic layer within MD-1 40° to 90° and universal hardness 2.0 to 20.0 N/mm² at 5 µm indentation depth. This optimized parameter range enables the material to maintain both flexibility for nip formation and resistance to compression set, resolving the contradiction between adaptability and stability.
Solution Approach 2:
The patent uses composite materials by combining specific elastomer types (silicone rubber, polyurethane, or fluororubber) with controlled crosslinking densities and hardness parameters. This composite approach creates an elastic layer that simultaneously achieves the required flexibility and compression resistance, balancing adaptability and structural stability.
2Ease of operation
If the elastic layer is made softer to improve nip formation, then the ease of operation is improved, but the structural integrity deteriorates
Solution Approach 1:
The patent resolves this contradiction through parameter changes by setting the universal hardness within a specific range of 2.0 to 20.0 N/mm² at 5 µm indentation depth. This controlled softness allows the elastic layer to conform to the photosensitive member surface for easy nip formation while maintaining sufficient structural integrity through optimized material composition and crosslinking.
3Strength
If the elastic layer is made harder to improve structural integrity, then the strength is improved, but the flexibility deteriorates
Solution Approach 1:
The patent applies parameter changes by optimizing the MD-1 hardness to 40° to 90° and universal hardness to 2.0 to 20.0 N/mm². This balanced parameter selection ensures the elastic layer has sufficient structural integrity while maintaining the flexibility needed for proper nip formation and adaptation to the photosensitive member surface.
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 compression set and ensures a uniform nip, leading to stable high-quality electrophotographic image output by controlling the hardness difference between the surface and inside of the elastic layer.
Implementation Method 1
an elastic layer, wherein the elastic layer has an MD-1 hardness of from 55 to 85° at the surface thereof, and has a universal hardness of 2.0 to 20.0 N/mm 2 at an indentation depth of 5 µm from the surface thereof
Data Source
Figure 1~2
Figure 3
AI summary
Provided is a charging member capable of suppressing occurrence of compression set while having flexibility enough to ensure a nip with a photosensitive member. The charging member comprises a support and an elastic layer, wherein the elastic layer has an MD-1 hardness of from 55 to 85° at the surface thereof, and has a universal hardness of 2.0 to 20.0 N/mm2 at an indentation depth of 5 µm from the surface thereof.