Bi-layer Polyurethane Cleaning Blade Edge Droop Resistance
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Solution Overview
Problem
Conventional cleaning blades for electrophotographic processes face challenges in achieving high durability, wear resistance, and edge droop resistance, often resulting in surface exfoliation or edge drooping of photoreceptors due to increased hardness and inadequate multi-layer structures.
Innovation Solution
A bi-layer cleaning blade member comprising a polyurethane cleaning layer and an elastic layer, where the cleaning layer is formed from a castable polyurethane composition with a diamino compound having a melting point of 80° C. or lower, and the elastic layer is formed from a composition with a short-chain diol and triol, with specific Young's modulus contribution factors and ratios to ensure excellent wear and edge droop resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the hardness of a conventional single-layer cleaning blade is increased to enhance durability, then wear resistance is improved, but excessive pressure is applied to the photoreceptor resulting in surface exfoliation or edge drooping
Solution Approach 1:
The cleaning blade is divided into multiple layers with different functions: a hard cleaning layer for wear resistance and a soft elastic layer for pressure distribution. This segmentation allows each layer to perform its specific function without causing harmful effects to the photoreceptor.
Solution Approach 2:
The cleaning blade uses a composite structure combining a polyurethane cleaning layer with high hardness for wear resistance and a polyurethane elastic layer with low hardness for cushioning. This composite material approach resolves the contradiction between needing high strength and avoiding harmful pressure effects.
2Object-affected harmful factors
If a multi-layer structure is used to prevent edge drooping, then edge droop resistance is improved, but wear resistance and edge droop resistance remain unsatisfactory
Solution Approach 1:
Different regions of the cleaning blade are given different properties: the cleaning layer has high hardness for wear resistance where it contacts the photoreceptor surface, while the elastic layer has low hardness for edge support and pressure distribution. This local differentiation of material properties optimizes both wear resistance and edge droop resistance.
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 provides a high-durability cleaning blade member with enhanced wear resistance and edge droop resistance, preventing surface exfoliation and edge drooping, while maintaining effective toner removal performance without damaging photoreceptors.
Implementation Method 1
a polyurethane member produced through curing and molding a castable polyurethane composition containing a long-chain polyol, a polyisocyanate
Data Source
AI summary
A cleaning blade member includes a cleaning layer and an elastic layer provided on the cleaning layer's back surface. Both are formed of a polyurethane member produced through curing and molding a castable polyurethane composition, the cleaning layer containing a long-chain polyol, a polyisocyanate, and a diamino compound having a melting point≦80° C., the elastic layer containing a long-chain polyol, a polyisocyanate, a short-chain diol, and a short-chain triol, and has a percent edge drooping≦7.0%, the cleaning and elastic layers have Young's modulus contribution factors Ra and Rb, respectively. (Rb/Ra)=0.05-6.0. Ra=[TaEa/(Ta+Tb)]. Rb=[TbEb/(Ta+Tb)]. Ea and Eb are Young's modulus of the cleaning and elastic layers, respectively. Ta and Tb represent the thicknesses of the cleaning and elastic layers, respectively, and the overall Young's modulus of the cleaning layer and elastic layer is (Ra+Rb)=5.0-14.0 MPa.