Developing Member Surface Layer Tg Control for Toner Sticking and C Set
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Solution Overview
Problem
In electrophotographic systems, developing members experience toner sticking and compression permanent distortion (C set) issues, particularly under varying environmental conditions, affecting image quality and durability.
Innovation Solution
A developing member with a surface layer composed of a urethane resin and an acrylic resin, featuring specific structural formulas that enhance flexibility and reduce toner adhesion, is used. The surface layer includes structures represented by structural formulas (1), (2), (3), and (4), with a glass transition point of 20° C. or higher and 120° C. or lower, and a second resin with a glass transition point of 50° C. or higher and 120° C. or lower, to prevent C set and toner filming.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the surface layer of the developing member is made more flexible to suppress toner sticking under low-temperature and low-humidity conditions, then toner adhesion is reduced, but compression permanent distortion (C set) occurs more easily when the developer regulating blade stands still for a long period
Solution Approach 1:
The patent applies parameter changes by carefully controlling the glass transition temperature (Tg) of the surface layer material. By setting Tg within a specific range (20°C to 120°C), the surface layer achieves optimal balance between flexibility for toner release and structural stability to resist compression permanent distortion. This parameter optimization allows the material to maintain appropriate softness for preventing toner sticking while retaining enough rigidity to avoid deformation under prolonged blade contact.
Solution Approach 2:
The patent employs composite materials by combining the surface layer material with specific resin components having controlled Tg values. The surface layer comprises a composite formulation including the base material and resin components in defined proportions, creating a material system that integrates both flexibility and dimensional stability. This composite approach enables the surface layer to exhibit dual characteristics: sufficient softness for toner release and adequate structural integrity to prevent C set.
2Stability of the object's composition
If a conventional surface layer material is used to maintain structural stability, then compression permanent distortion is minimized, but toner sticking occurs under low-temperature and low-humidity environments
Solution Approach 1:
The patent resolves this contradiction by changing the thermal parameter (glass transition temperature) of the surface layer material to a specific range (20°C to 120°C). This parameter adjustment ensures the material remains sufficiently flexible at operating temperatures to prevent toner adhesion, while maintaining structural stability to avoid compression permanent distortion. The controlled Tg range optimizes the material's viscoelastic properties for dual performance.
Solution Approach 2:
The patent uses composite materials formulation where the surface layer comprises a combination of base material and resin components with specific Tg values and proportions. This composite structure enables the surface layer to exhibit synergistic properties: the base material provides structural framework for stability, while the resin components contribute flexibility and toner release characteristics, achieving both structural stability and anti-sticking performance.
Data Source
AI summary
A high quality developing member that is excellent in deformation recovery property under a high temperature and that also satisfies filming resistance under a low temperature is provided. The developing member of the present invention includes a mandrel, an elastic layer formed on the outer periphery surface of the mandrel, and a surface layer covering the outer periphery surface of the elastic layer, wherein the surface layer contains a first resin and a second resin, the first resin has a particular structure between adjacent two urethane linkages, and the second resin is a resin having a particular structure and having a glass transition point Tg of 20° C. or higher and 120° C. or lower.