Developing Member Surface Layer with Zinc Oxide
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Solution Overview
Problem
Existing developing members for electrophotographic apparatuses face challenges in maintaining stable toner conveyance and triboelectric charge provision across varying environmental conditions, particularly experiencing excessive stress and toner deterioration under low-temperature, low-humidity environments, leading to issues like fogging and surface filming.
Innovation Solution
A developing member comprising a mandrel with an elastic layer and a surface layer containing polyurethane and zinc oxide particles, where the polyurethane has specific structural formulas that reduce polarity and crystallinity, enhancing flexibility and hydrophobicity, and the zinc oxide particles alleviate voltage dependence, preventing current leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a polyurethane developing roller is used to provide proper triboelectric charge under high-temperature and high-humidity conditions, then the triboelectric charge-providing property is improved, but the surface hardness increases under low-temperature and low-humidity conditions causing excessive stress on toner
Solution Approach 1:
The invention changes the chemical structure parameters of the polyurethane by introducing specific side chain structures (formulae 1-4) that modify the material's physical properties. These structural changes reduce polarity and crystallinity, enabling the polyurethane to maintain appropriate surface hardness across different temperature and humidity conditions while preserving triboelectric charge capability
Solution Approach 2:
The invention creates a composite material system by combining polyurethane with specific side chain structures and zinc oxide particles. This composite structure in the surface layer provides both the required triboelectric charge-providing property and controlled surface hardness that prevents excessive stress on toner under varying environmental conditions
2Stability of the object's composition
If the surface hardness of the developing roller is increased to maintain structural integrity, then the structural stability is improved, but the toner deteriorates and films on the surface under low-temperature conditions
Solution Approach 1:
The invention modifies the polyurethane's chemical structure by introducing side chains with formulae 1-4 that reduce crystallinity and polarity. This structural parameter change enables the material to maintain stable surface properties across temperature variations, preventing both excessive hardness that causes toner damage and softness that compromises structural integrity
Solution Approach 2:
The invention creates a surface layer with distinct local quality by incorporating polyurethane with specific side chain structures and zinc oxide particles. This localized composition provides the necessary surface characteristics for toner handling while maintaining overall roller structural stability through the layered construction
3Object-affected harmful factors
If a conventional polyurethane is used to suppress fogging under high-temperature and high-humidity environments, then the fogging suppression is improved, but the surface polarity causes toner adhesion and filming under low-temperature conditions
Solution Approach 1:
The invention changes the polarity parameter of the polyurethane by introducing side chain structures (formulae 1-4) that reduce overall polarity. This parameter change allows the material to suppress fogging under high-temperature, high-humidity conditions while simultaneously reducing toner adhesion and filming under low-temperature conditions
Solution Approach 2:
The invention uses zinc oxide particles as an intermediary substance dispersed in the surface layer. These particles interact with the reduced-polarity polyurethane to further control surface properties, preventing toner adhesion and filming while maintaining fogging suppression across different environmental conditions
4Adaptability or versatility
If the polyurethane structure is modified to reduce polarity and improve flexibility, then the adaptability to different environments is improved, but the surface layer requires additional components to prevent voltage dependence and current leakage
Solution Approach 1:
The invention modifies the polyurethane's chemical structure by introducing side chains with formulae 1-4 that reduce polarity and crystallinity. This structural parameter change enhances environmental adaptability and flexibility while the added zinc oxide particles address voltage dependence and current leakage issues through their electrical properties
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 ensures stable toner conveyance and triboelectric charge provision across different environments, preventing fogging and filming, and maintaining image quality under high-temperature, high-humidity conditions while preventing horizontal streaks due to blade bias leaks.
Implementation Method 1
the polyurethane has, between two adjacent urethane bonds, one or both of structures selected from structures according to the following item (A) and the following item (B)... enhancing flexibility and hydrophobicity
Implementation Method 2
the surface layer contains a polyurethane and zinc oxide particles dispersed in the polyurethane... the zinc oxide particles alleviate voltage dependence, preventing current leakage
Implementation Method 3
a function of providing the toner with proper charge... capable of providing toner with proper triboelectric charge
Data Source
AI summary
Provided is a developing member capable of exerting stable performance under various environments. The developing member comprises a mandrel, an elastic layer formed on a periphery of the mandrel, and a surface layer covering a peripheral surface of the elastic layer. The surface layer contains a polyurethane and zinc oxide particles dispersed in the polyurethane, and the polyurethane has, between two adjacent urethane bonds, one or both of structures selected from structures according to the following item (A) and the following item (B): (A) a structure represented by the following structural formula (1), and one or both of structures selected from a structure represented by the following structural formula (2) and a structure represented by the following structural formula (3); and (B) a structure represented by the following structural formula (4).