Urethane Cleaning Blade with Graded Young's Modulus for Toner Removal
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Solution Overview
Problem
Existing cleaning blades face challenges in effectively removing toner with small particle diameter and high sphericity from electrophotographic photoconductors, leading to faulty cleaning, squeaking, and surface layer peeling, especially under severe conditions with high humidity and temperature.
Innovation Solution
A cleaning blade with an elastic body portion containing urethane rubber and a support member, featuring a first region with a gradually decreasing Young's modulus in the depth direction and a second region with a constant modulus, designed to minimize friction and vibration transmission, thereby preventing squeaking and surface layer peeling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the contact pressure between the cleaning blade and the member to be cleaned is increased to reduce the gap, then the toner removal efficiency is improved, but the frictional force increases causing the cleaning blade to turn up and generate squeaking
Solution Approach 1:
The cleaning blade employs a two-layer structure where the surface layer (10-50 Shore A hardness) provides low friction to prevent turning-up and squeaking, while the core layer (30-70 Shore A hardness) maintains sufficient contact pressure for effective toner removal. This local differentiation of material properties resolves the contradiction between reducing friction and maintaining cleaning effectiveness.
2Object-generated harmful factors
If the hardness of the cleaning blade surface layer is increased to reduce frictional force and suppress squeaking, then the frictional force decreases, but the true contact area with the member surface becomes smaller reducing cleaning effectiveness
Solution Approach 1:
The invention applies different hardness levels to different regions of the cleaning blade: the surface layer has lower hardness (10-50 Shore A) to maximize contact area and reduce friction, while the core layer has higher hardness (30-70 Shore A) to maintain structural integrity and contact pressure. This resolves the contradiction by localizing the hardness property rather than applying it uniformly.
3Object-generated harmful factors
If a hard surface layer is formed on the cleaning blade to reduce friction, then squeaking is suppressed, but surface layer peeling occurs under severe conditions with high humidity and temperature
Solution Approach 1:
The cleaning blade uses a composite structure with a surface layer and core layer made of different urethane rubber compositions with specific hardness ranges. The surface layer (10-50 Shore A) provides low friction to prevent squeaking, while the core layer (30-70 Shore A) provides structural stability. The composite nature allows each layer to perform its function without causing peeling, resolving the contradiction between squeaking suppression and surface stability.
4Duration of action of stationary object
If the cleaning blade uses urethane rubber with high wear resistance and permanent deformation resistance, then the blade durability is improved, but the ability to follow surface unevenness of the member is reduced
Solution Approach 1:
The cleaning blade employs a two-layer structure where the surface layer (10-50 Shore A hardness) is softer to enhance surface following capability and adaptability, while the core layer (30-70 Shore A hardness) provides wear resistance and structural durability. This local differentiation allows the blade to simultaneously achieve both surface adaptation and long-term durability.
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 squeaking and surface layer peeling, stabilizes contact pressure, and enhances the cleaning blade's ability to follow surface unevenness, ensuring stable cleaning performance even under severe conditions.
Implementation Method 1
a free end portion of the elastic body portion has a first region in which the Young's modulus gradually decreases in the depth direction from the principal surface facing the surface of the member to be cleaned
Implementation Method 2
as an increase in the contact pressure between the cleaning blade and the member to be cleaned, there is a tendency for the frictional force between the cleaning blade and the member to be cleaned to be higher
Data Source
AI summary
To provide a cleaning blade having an elastic body portion containing urethane rubber and a support member supporting the elastic body portion.A free end portion of the elastic body has a first region in which the Young's modulus gradually decreases in the depth direction from the principal surface facing the surface of the member to be cleaned on the edge face side and a second region in which the Young's modulus does not vary in the depth direction from the principal surface on the side closer to the support member relative to the first region.