Toner Composition for Low-Temperature Fixing and Storage Stability
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Solution Overview
Problem
Conventional toners face challenges in achieving both low-temperature fixability and heat-resistant storage stability, with existing methods failing to prevent toner aggregation, trailing-edge offset, density unevenness, and fogging, especially in high-temperature environments, while also ensuring stacking resistance.
Innovation Solution
A toner composition comprising a binder resin, colorant, and release agent, with specific viscoelastic properties defined by the ratios G′(50)/G′(80) and T(107), utilizing a crystalline polyester resin that reversibly dissociates and rebinds with heat to balance viscoelasticity and elasticity, thereby achieving low-temperature fixability and heat-resistant storage stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the glass transition temperature of the binder resin is lowered to achieve low-temperature fixability, then the binder resin undergoes plastic deformation more easily, but heat-resistant storage stability deteriorates
Solution Approach 1:
The patent changes the chemical composition parameters of the binder resin by incorporating specific ratios of crystalline polyester (10-40 mass%) and amorphous polyester (60-85 mass%), along with controlling the glass transition temperature (40-70°C) and melting point (60-120°C) to achieve both low-temperature fixability and heat-resistant storage stability
Solution Approach 2:
The patent uses a composite binder resin system combining crystalline polyester and amorphous polyester in specific proportions, where the crystalline component provides heat-resistant stability and the amorphous component enables low-temperature deformation, resolving the contradiction between fixing temperature and storage stability
2Temperature
If a crystalline resin is exposed at the surface of toner to control viscoelasticity, then low-temperature fixability is improved, but toner particles aggregate due to stress received when stirred in a developing device
Solution Approach 1:
The patent optimizes the viscoelasticity parameters by controlling the storage elastic modulus ratio G′(50)/G′(80) to be 3.0×10² or more and the temperature T(107) to be 75°C or more, achieving both low-temperature fixability and particle stability without surface exposure issues
Solution Approach 2:
The patent introduces an amorphous polyester as an intermediary component that mediates between the crystalline polyester and the toner particle structure, preventing aggregation while maintaining the viscoelasticity needed for low-temperature fixing
3Temperature
If a crystalline polyester with low crystallization speed or large amount is introduced to lower viscoelasticity, then low-temperature fixability is improved, but stacking occurs because elastic recovery of the fixed toner becomes slower
Solution Approach 1:
The patent precisely controls the crystallization speed and amount of crystalline polyester, along with optimizing the viscoelasticity parameters (G′(50)/G′(80) ≥ 3.0×10² and T(107) ≥ 75°C), to achieve fast elastic recovery that prevents stacking while maintaining low-temperature fixability
Solution Approach 2:
The patent creates a dynamic balance in the toner's viscoelastic properties by using a combination of crystalline and amorphous polyesters, allowing the toner to exhibit appropriate elasticity at different temperatures - flexible during fixing and rigid during storage to prevent stacking
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 composition ensures high-quality images with improved low-temperature fixability and heat-resistant storage stability, reducing undesirable phenomena such as toner particle cohesion and stacking, while maintaining mechanical durability and chargeability.
Implementation Method 1
utilizing a crystalline polyester resin that reversibly dissociates and rebinds with heat to balance viscoelasticity and elasticity
Implementation Method 2
3.0×10²≤G′(50)/G′(80) where G′(50) represents a storage elastic modulus at 50 degrees C., and G′(80) represents the storage elastic modulus at 80 degrees C.
Data Source
AI summary
A toner is provided. The toner comprises a binder resin, a colorant, and a release agent. The toner satisfies the following relations (1) and (2):3.0×102≤G′(50)/G′(80) (1)T(107)≥75 degrees C. (2)where G′(50) represents a storage elastic modulus at 50 degrees C., G′(80) represents the storage elastic modulus at 80 degrees C., and T(107) represents a temperature at which the storage elastic modulus is 107 Pa or higher during a temperature fall from 100 degrees C. to 30 degrees C., in a measurement of dynamic viscoelasticity of the toner.