Electrophotographic Polyurethane Cleaning Blade for Scratched Surfaces
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Solution Overview
Problem
Existing electrophotographic cleaning blades with polymeric MDI as a raw material for polyurethane exhibit a high elastic modulus, leading to a narrow nip width and increased contact pressure, which causes cleaning defects when scratches occur on the to-be-cleaned member, compromising long-term cleaning performance.
Innovation Solution
The cleaning blade is designed with a polyurethane elastic member having specific storage elastic modulus ranges (E′(1) of 12.0 to 18.0 MPa at 1×10−3 Hz and E′(2) of 530.0 to 1500.0 MPa at 1×104 Hz, achieved by controlling the molecular mobility of hard and soft segments through the use of trimethylolpropane as a crosslinking component and minimizing polymeric MDI, to maintain an appropriate nip width and suppress stick-slip.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polymeric MDI is used as a raw material for polyurethane to achieve fine dispersion of hard segments, then cleaning performance is improved, but the elastic modulus becomes too high causing narrow nip width and cleaning defects when scratches occur
Solution Approach 1:
The patent changes the chemical structure parameters of the polyisocyanate component, specifically using 4,4'-dicyclohexylmethane diisocyanate (H12MDI) instead of polymeric MDI. This parameter change in the raw material composition results in a polyurethane elastic member with reduced elastic modulus while maintaining fine dispersion of hard segments, thereby achieving both reliable cleaning performance and appropriate nip width even when scratches occur on the photoreceptor surface.
2Force
If high elastic modulus is maintained to increase contact pressure, then cleaning effectiveness is improved, but nip width becomes too narrow causing cleaning defects at scratch portions
Solution Approach 1:
The patent modifies the elastic modulus parameter of the polyurethane elastic member by changing the polyisocyanate raw material from polymeric MDI to H12MDI. This parameter change achieves an optimal balance where the elastic modulus is reduced to provide sufficient nip width (preventing cleaning defects at scratches) while maintaining adequate contact pressure for effective cleaning through the controlled molecular structure of the resulting polyurethane.
3Reliability
If polymeric MDI is used to suppress aggregation of hard segments, then cleaning performance is enhanced, but the resulting high elastic modulus causes stick-slip phenomenon
Solution Approach 1:
The patent changes the polyisocyanate component parameter from polymeric MDI to 4,4'-dicyclohexylmethane diisocyanate (H12MDI), which has different molecular weight and structural characteristics. This parameter change produces a polyurethane elastic member with reduced elastic modulus that maintains fine dispersion of hard segments while eliminating the stick-slip phenomenon, thereby achieving both reliable cleaning performance and stable contact during operation.
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
This design stabilizes cleaning performance over a long period by ensuring an adequate nip width and preventing toner and additive slipping, even with scratches, thereby maintaining high-quality image formation.
Implementation Method 1
the storage elastic modulus at a vibration frequency of 1×10−3 Hz is 12.0 to 18.0 MPa, and the storage elastic modulus at a vibration frequency of 1×104 Hz is 530.0 to 1500.0 MPa
Data Source
AI summary
An electrophotographic cleaning blade comprising an elastic member comprising a polyurethane; and a support member supporting the elastic member, the electrophotographic cleaning blade cleans a surface of a to-be-cleaned member by bringing a part of the elastic member into contact with the surface of the to-be-cleaned member that is moving, wherein in an environment of 8° C., when a storage elastic modulus of the elastic member at a vibration frequency of 1×10−3 Hz is denoted as E′(1) and a storage elastic modulus at a vibration frequency of 1×104 Hz is denoted as E′(2), the E′(1) is 12.0 to 18.0 MPa, and the E′(2) is 530.0 to 1500.0 MPa.