Cleaning Blade Hard Segment Domain Size Control
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Solution Overview
Problem
In electrophotographic image forming apparatuses, cleaning blades used to remove toner and other foreign substances often experience permanent deformation, especially at higher temperatures, leading to changes in pressing pressure and increased passage of toner and additives between the blade and the image-carrying member, resulting in streak-like image defects.
Innovation Solution
A cleaning blade with a polyurethane member containing a hard segment component and a soft segment component, where the domain particle size of the hard segment component is between 45 nm and 100 nm, reducing permanent deformation by lowering the glass transition temperature and enhancing molecular motion, while maintaining necessary strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the cleaning blade is made with conventional polyurethane material, then it has sufficient strength for cleaning, but it experiences permanent deformation at higher temperatures leading to pressing pressure changes and image defects
Solution Approach 1:
The patent applies parameter changes by controlling the domain particle size of the hard segment component within a specific range (45-100 nm) and adjusting the glass transition temperature to -30°C or lower. These parameter modifications enable the polyurethane to maintain dimensional stability and resist permanent deformation at high temperatures while preserving cleaning effectiveness, thereby preventing toner passage and image defects.
Solution Approach 2:
The patent utilizes composite material structure by creating a polyurethane composed of distinct hard segment domains dispersed in a soft segment matrix. This composite architecture, with hard segments forming discrete domains of controlled size, provides both the strength needed for cleaning and the thermal stability to resist deformation, solving the contradiction between durability and temperature resistance.
2Reliability
If the hard segment domain particle size is reduced to improve flexibility and reduce deformation, then permanent deformation decreases, but the strength of the cleaning blade may be compromised
Solution Approach 1:
The patent resolves this contradiction by precisely controlling the domain particle size parameter within the optimal range of 45-100 nm. This specific size range provides the right balance: small enough to allow molecular motion and reduce permanent deformation, yet large enough to maintain structural strength and cleaning effectiveness. The glass transition temperature is simultaneously adjusted to -30°C or lower to enhance flexibility without sacrificing strength.
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 reduces permanent deformation and maintains the necessary strength of the cleaning blade, preventing toner and additive passage and minimizing image defects, even in high-temperature environments.
Implementation Method 1
reducing permanent deformation by lowering the glass transition temperature and enhancing molecular motion
Data Source
AI summary
A cleaning blade includes a polyurethane member that constitutes at least a contact portion that comes in contact with a member to be cleaned. The polyurethane member contains a polyurethane containing a hard segment component and a soft segment component. The hard segment component has a domain particle size of about 45 nm or more and about 100 nm or less.