Polysiloxane Polyurethane Cleaning Blade for Humidity-Stable Drum Cleaning
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Solution Overview
Problem
Existing cleaning blades in electrophotographic devices face challenges in achieving high-level cleaning performance and reducing abrasion of the photosensitive drum while maintaining stability in high humidity environments, as they tend to lose hardness due to moisture absorption.
Innovation Solution
A cleaning blade composed of a polyurethane elastomer with a polysiloxane segment, having a specific storage elastic modulus and spin-spin relaxation time, is designed to minimize moisture absorption and maintain hardness stability, incorporating a dense crosslinked structure and polysiloxane segments to enhance durability and cleaning efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If the hardness of the cleaning blade is set low to reduce abrasion of the photosensitive drum, then drum abrasion is reduced and lifespan is prolonged, but cleaning performance deteriorates and toner may slip through
Solution Approach 1:
The patent precisely controls the storage elastic modulus parameter within 12.0 to 18.0 MPa at 24°C and vibration frequency of 1×10−3 Hz, and controls the spin-spin relaxation time (T2L) to be 250 to 360 μs at 50°C. These parameter optimizations enable the cleaning blade to achieve both low enough hardness to reduce drum abrasion and high enough hardness to prevent toner slip-through, resolving the contradiction between drum lifespan and cleaning performance.
2Reliability
If the hardness of the cleaning blade is controlled for optimal cleaning performance, then cleaning performance is improved, but the blade becomes sensitive to humidity-induced hardness loss
Solution Approach 1:
The patent uses a polyurethane elastomer composite material that combines the advantages of polyurethane (good mechanical properties and processability) with elastomer characteristics (flexibility and humidity resistance). This composite material structure inherently provides resistance to moisture absorption while maintaining the required hardness range, thus improving both cleaning performance and hardness stability without requiring additional protective measures.
3Duration of action of stationary object
If a soft cleaning blade is used to reduce drum abrasion, then drum lifespan is prolonged, but cleaning defects occur in high-speed systems with spherical toner
Solution Approach 1:
The patent optimizes the storage elastic modulus to 12.0 to 18.0 MPa and controls the spin-spin relaxation time to 250 to 360 μs, creating a cleaning blade with precisely controlled mechanical properties. This parameter optimization enables the blade to be soft enough to reduce drum abrasion yet maintain sufficient hardness to effectively clean spherical toner particles in high-speed printing systems, thereby improving both drum lifespan and cleaning quality.
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 cleaning blade exhibits excellent cleaning performance and prolonged lifespan by reducing moisture absorption, ensuring stable contact with the to-be-cleaned member even in high humidity conditions.
Implementation Method 1
the elastic member comprises a polyurethane... in pulse NMR measurement in an environment at 50° C. of a sample sampled from the elastic member, there is a segment with a spin-spin relaxation time (T2L) of 250 to 360 μs... the polyurethane comprises a polyurethane elastomer... the polysiloxane segment is bonded to a structure comprising a polyurethane skeleton
Data Source
AI summary
An electrophotographic cleaning blade comprising an elastic member comprising a polyurethane and a support member that supports the elastic member, wherein, a storage elastic modulus of the elastic member at a vibration frequency of 1×10−3 Hz is 12.0 to 18.0 MPa, in pulse NMR measurement in an environment at 50° C. of a sample sampled from the elastic member, there is a segment with a spin-spin relaxation time (T2L) of 250 to 360 μs, the polyurethane comprises a polyurethane elastomer comprising a polysiloxane segment having a specific structure, and the polysiloxane segment is bonded to a polyurethane skeleton in the polyurethane elastomer.