Domain-Matrix Toner for Low-Temperature Fixing and Storage Stability
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Solution Overview
Problem
Existing toners face challenges in achieving both low-temperature fixability and heat-resistant storage stability, as decreasing the glass transition point of binder resins to improve fixability compromises storage stability, and using crystalline resins alone may lead to soiling of the fixing device.
Innovation Solution
A toner composition featuring a domain-matrix structure comprising a crystalline resin matrix and amorphous resin domains, with a maximum endothermic peak temperature of 50°C to 80°C, a storage elastic modulus ratio of G′(−5)/G′(+5) ≥ 50, and a maximum loss tangent of 0.0 to 1.50, which enhances low-temperature fixability while maintaining heat-resistant storage stability and reducing the likelihood of soiling the fixing device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the glass transition point of the binder resin is decreased to improve low-temperature fixability, then the low-temperature fixability is improved, but the heat-resistant storage stability deteriorates
Solution Approach 1:
The patent uses a composite resin system comprising both crystalline resin and amorphous resin. The crystalline resin provides low-temperature fixability through its sharp melting behavior, while the amorphous resin provides heat-resistant storage stability. This composite approach allows the toner to achieve both low-temperature fixability and heat-resistant storage stability simultaneously, resolving the contradiction between these two properties.
2Reliability
If a crystalline resin is used to achieve both low-temperature fixability and heat-resistant storage stability, then both properties are improved, but the fixing device may be soiled
Solution Approach 1:
The patent introduces a domain-matrix structure where crystalline resin forms domains dispersed in an amorphous resin matrix. This local structural differentiation allows the crystalline resin to provide sharp melting and low-temperature fixability in specific domains, while the amorphous resin matrix prevents excessive viscosity and soiling of the fixing device. The amorphous resin acts as a continuous phase that controls the overall flow and adhesion characteristics.
3Temperature
If the glass transition point is decreased to improve low-temperature fixability, then fixability is improved, but the viscosity behavior becomes problematic
Solution Approach 1:
The patent changes the thermal behavior parameters by using crystalline resin with a sharp melting point (50-80°C) instead of relying solely on glass transition point. The crystalline resin undergoes sudden melting at a specific temperature, providing a controlled transition from solid to viscous state during fixing. This parameter change allows low-temperature fixability while maintaining appropriate viscosity behavior, as the sharp melting provides a defined transition point rather than gradual softening.
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 high low-temperature fixability, heat-resistant storage stability, and reduced soiling of the fixing device, ensuring efficient and reliable operation in electrophotographic image forming apparatuses.
Implementation Method 1
the crystalline resin undergoes sudden melting (sharp melting) of crystals upon reaching the melting point, and experiences a sudden decrease in viscosity associated therewith
Implementation Method 2
The resin exhibits crystallinity as a result of crystallization caused by an orderly arrangement of pendant long-chain alkyl groups
Implementation Method 3
in a temperature range of from 50° C. to 130° C.
Data Source
AI summary
A toner includes a toner particle containing a resin component including a crystalline resin and an amorphous resin. In a cross-sectional observation of the toner particle, a domain-matrix structure which comprises a matrix containing the crystalline resin and domains containing the amorphous resin is observed. The maximum endothermic peak temperature Tm of the toner determined by DSC is 50° C. to 80° C. When the storage elastic modulus of the toner at a temperature 5° C. lower than Tm is G′(−5) (Pa), and the storage elastic modulus of the toner at a temperature 5° C. higher than Tm is G′(+5) (Pa), G′(−5) and G′(+5) satisfy inequality (1), and when the maximum loss tangent of the toner in a temperature range of from 50° C. to 130° C. is tan δ (Max), tan δ (Max) satisfies inequality (2).