Cleaning Blade Surface Hardness via Nitrogen Gradient
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing cleaning blades for electrophotographic devices face issues with flexibility, surface hardness, and wear resistance, often requiring excessive isocyanate application and subsequent removal, which affects durability and cleaning performance.
Innovation Solution
A cleaning blade with a treated surface layer formed using a bifunctional isocyanate compound, polyol, and organic solvent, where the nitrogen concentration gradient is controlled to achieve high surface hardness without compromising flexibility, eliminating the need for a coating layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the contact portion of a polyurethane blade is modified to have high hardness through impregnation with isocyanate compound, then wear resistance is improved, but the blade flexibility is impaired and warpage occurs
Solution Approach 1:
The patent applies local quality by creating a surface treatment layer only at the contact portion of the blade with a thickness of 1-10 μm. This localized treatment provides high hardness and wear resistance exactly where needed (the contact surface) while leaving the bulk of the blade unchanged, thereby preserving overall blade flexibility and preventing warpage.
Solution Approach 2:
The patent uses parameter changes by controlling the isocyanate compound concentration (0.1-10 wt%) and the thickness of the treated surface layer (1-10 μm). By precisely adjusting these parameters, the surface achieves high hardness for wear resistance while the thin layer depth ensures the underlying flexible blade structure remains intact, resolving the contradiction between surface durability and overall flexibility.
2Strength
If a thick treated surface layer is formed to achieve target surface hardness, then wear resistance is improved, but excess isocyanate must be removed requiring additional processing steps
Solution Approach 1:
The patent applies partial action by forming a thin surface treatment layer (1-10 μm) that is sufficient to provide the required surface hardness and wear resistance, but not so thick as to cause excess isocyanate accumulation. This optimized thickness achieves the necessary surface properties while avoiding the need for additional removal or wiping steps.
3Strength
If the nitrogen concentration at the surface is increased to enhance hardness, then wear resistance is improved, but the blade loses flexibility due to large concentration difference
Solution Approach 1:
The patent creates a localized gradient where nitrogen concentration (from isocyanate compound) is increased only in the superficial 1-10 μm layer at the contact surface. This localized enrichment provides high surface hardness while the gradient naturally transitions to lower concentration in the bulk material, preserving blade flexibility and avoiding the brittleness that would result from uniform high nitrogen concentration throughout.
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 maintains flexibility while achieving high surface hardness, ensuring long-term cleaning performance and reducing the need for surface treatment removal steps.
Implementation Method 1
a polyurethane blade is impregnated with an isocyanate compound, to thereby induce reaction between the polyurethane and the isocyanate compound, whereby the hardness is enhanced at only the surface or a portion near the surface
Implementation Method 2
a surface treatment liquid containing a bifunctional isocyanate compound, at least one polyol selected from a bifunctional polyol and a trifunctional polyol, and an organic solvent
Data Source
AI summary
A cleaning blade has an elastic body formed of a urethane elastomer, and a treated surface layer formed at least at a portion which comes into contact with a contact target of the elastic body. The treated surface layer is formed through impregnating a surface portion of the elastic body with a surface treatment liquid containing a bifunctional isocyanate compound, at least one polyol, and an organic solvent; or a surface treatment liquid containing an isocyanate group-containing compound having an isocyanate group at an end thereof, which compound is a reaction product of the bifunctional isocyanate compound with the at least one polyol, and an organic solvent, and curing the surface treatment liquid. The difference between the nitrogen concentration at the surface and the nitrogen concentration in the elastic body at a depth of 0.5 mm from the surface of the treated surface layer is 0.02 to 0.15 mass %.