Core-Shell Toner with Balanced Hardness for Fixability
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Solution Overview
Problem
Toner designs that aim to simultaneously achieve low temperature fixability and heat resistant storage stability often compromise on ductility and color reproducibility, as increasing the hardness for heat resistance degrades these properties.
Innovation Solution
A toner with a spin-spin relaxation time of 1.80 to 7.00 msec at 90°C, achieved by optimizing the content and dispersion of crystalline resin and the thickness of the shell layer in a core-shell structure, balances molecular mobility to ensure good fixability, ductility, and color reproducibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the toner hardness is increased to achieve heat resistant storage stability, then the heat resistant storage stability is improved, but the ductility and color reproducibility are degraded
Solution Approach 1:
The toner is divided into a core region containing crystalline polyester resin (providing heat resistance) and a shell layer containing amorphous polyester resin (providing ductility and color reproducibility). This segmentation allows each region to independently contribute its specific properties without compromising the other.
Solution Approach 2:
Different regions of the toner particle are given different resin compositions and properties: the core has high crystallinity for heat resistance, while the shell has amorphous structure for ductility. This local differentiation resolves the contradiction by allowing each property to be optimized in its appropriate location.
2Reliability
If the toner hardness is increased to achieve heat resistant storage stability, then the heat resistant storage stability is improved, but the color reproducibility is degraded
Solution Approach 1:
The toner is divided into a core region containing crystalline polyester resin (providing heat resistance) and a shell layer containing amorphous polyester resin (providing ductility and color reproducibility). This segmentation allows each region to independently contribute its specific properties without compromising the other.
Solution Approach 2:
Different regions of the toner particle are given different resin compositions and properties: the core has high crystallinity for heat resistance, while the shell has amorphous structure for ductility. This local differentiation resolves the contradiction by allowing each property to be optimized in its appropriate location.
3Temperature
If the melting point of the toner is lowered to achieve low temperature fixability, then the low temperature fixability is improved, but the heat resistant storage stability is degraded
Solution Approach 1:
The toner is divided into a core region containing crystalline polyester resin (providing heat resistance) and a shell layer containing amorphous polyester resin (providing ductility and color reproducibility). This segmentation allows each region to independently contribute its specific properties without compromising the other.
Solution Approach 2:
The resin composition parameters are changed to include both crystalline and amorphous polyester resins in specific proportions. The crystalline resin maintains high melting point for heat resistance, while the amorphous resin lowers the overall melting point for low temperature fixing, thus resolving the contradiction through parameter optimization.
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 excellent low temperature fixability and color reproducibility while maintaining heat resistant storage stability, with a balanced hardness that prevents degradation in either property.
Implementation Method 1
a spin-spin relaxation time (t2) of the toner at 90°C obtained by Hahn Echo method of pulse NMR analysis is from 1.80 msec to 7.00 msec
Data Source
Figure 1
AI summary
Provided is [i] a toner including at least a colorant, a resin, and a releasing agent, wherein a spin-spin relaxation time (t2) of the toner at 90°C obtained by Hahn Echo method of pulse NMR analysis is from 1.80 msec to 7.00 msec. Also provided is [ii] a toner according to [i], wherein the spin-spin relaxation time (t2) of the toner at 90°C obtained by Hahn Echo method of pulse NMR analysis is from 3.80 msec to 5.90 msec.