Toner Crystallinity and Viscoelasticity for Fixing Stability
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Solution Overview
Problem
Conventional toners face challenges in achieving both low-temperature fixability and heat-resistance storage stability, as well as preventing toner flowability degradation and adhesion to developing members under varying humidity conditions.
Innovation Solution
A toner with crystallinity of 20 or greater and specific dynamic viscoelastic characteristics, including storage elastic modulus values measured within certain ranges, is developed to ensure low-temperature fixability and prevent flowability degradation and adhesion under high-temperature, high-humidity conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the softening characteristics of the toner are reformed to be set at a lower temperature to improve low-temperature fixability, then the fixing temperature is reduced, but the heat resistance storage stability is degraded
Solution Approach 1:
The invention changes the physical and chemical parameters of the binder resin by selecting specific resin types (polyester resin with Tg of 40-70°C and/or polyurethane resin with Tg of -50-50°C) and controlling their glass transition temperatures to achieve the desired balance between low-temperature fixability and heat resistance storage stability
Solution Approach 2:
The invention uses composite resin systems combining multiple resin types (polyester resin, polyurethane resin, and optionally polycarbonate resin) to achieve properties that cannot be obtained with a single resin type, balancing softening characteristics and storage stability
2Temperature
If the softening characteristics of the toner are reformed to be set at a lower temperature, then the fixing temperature is reduced, but the developing stability is degraded
Solution Approach 1:
The invention optimizes the glass transition temperature parameter of the binder resin within specific ranges (Tg of 40-70°C for polyester resin and/or Tg of -50-50°C for polyurethane resin) to maintain developing stability while achieving low-temperature fixability
Solution Approach 2:
The invention creates different functional zones within the toner structure by using a core-shell structure where the resin composition and properties are optimized for specific functions (development stability in the core, fixation properties in the shell)
3Temperature
If the softening characteristics of the toner are reformed to be set at a lower temperature, then the fixing temperature is reduced, but the toner adheres to the developing member under high-temperature, high-humidity conditions
Solution Approach 1:
The invention changes the viscoelastic parameters of the binder resin by selecting resin types with specific Tg ranges and controlling the resin composition to maintain appropriate viscosity and elasticity under high-temperature, high-humidity conditions, preventing toner adhesion to the developing member
Solution Approach 2:
The invention uses a carefully balanced resin system that provides sufficient stability under varying conditions without requiring expensive additional protective coatings or complex stabilizing additives
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 toner achieves ultimate low-temperature fixability and prevents flowability degradation and adhesion to developing members, maintaining stability across different humidity conditions.
Implementation Method 1
a crystalline resin can rapidly soften at the melting point of the resin
Implementation Method 2
the toner has crystallinity CX of 20 or greater
Implementation Method 3
a dynamic viscoelasticity characteristic in which a logarithmic value log G′(50) of storage elastic modulus (Pa) at 50° C. is from 6.5 to 8.0, and a logarithmic value log G′(65) of storage elastic modulus (Pa) at 65° C. is from 4.5 to 6.0
Data Source
AI summary
A toner of the present invention includes at least a colorant and a resin, has crystallinity CX or 20 or greater, and has a dynamic viscoelasticity characteristic in which a logarithmic value Log G′(50) of storage elastic modulus (Pa) at 50° C. is from 6.5 to 8.0 and a logarithmic value Log G′(65) of storage elastic modulus (Pa) at 65° C. is from 4.5 to 6.0, when the dynamic viscoelasticity characteristic is measured by temperature sweep from 40° C., at a frequency of 1 Hz, at a strain amount control of 0.1%, and at a temperature elevating rate of 2° C./min.