Core-Shell Toner Particles for Low-Temperature Fixing and High Gloss
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Solution Overview
Problem
Existing toners face challenges in achieving both low-temperature fixing performance and high image glossiness while maintaining stability and preventing contamination, as they tend to have contradictory properties such as low strength and high sensitivity to temperature changes.
Innovation Solution
A toner composition with toner particles produced by suspension polymerization, incorporating an inorganic fine powder and a specific core-shell structure with a polar resin, where the displacement levels in a micro-compression test at 25°C and 50°C, and the number average particle diameter satisfy specific ratios, ensuring the toner's durability and adhesion properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the binder resins are made to have a lower glass transition point or lower average molecular weight to improve low-temperature fixing performance, then the fixing performance is improved, but the toner strength decreases causing component contamination due to toner melt sticking or wax exudation
Solution Approach 1:
The toner particles are divided into a core region containing binder resin with low glass transition point (for low-temperature fixing) and a shell region with different properties (for strength and stability). This segmentation allows each region to fulfill its specific function without compromising the other.
Solution Approach 2:
The invention uses composite material structure combining different binder resins with complementary properties - one providing low Tg for easy fixing and another providing structural integrity. The composite structure achieves both low-temperature fixing capability and sufficient toner strength to prevent contamination.
2Manufacturing precision
If the average particle diameter is reduced to achieve high definition and high image quality, then the resolution is improved, but it becomes difficult to achieve both resistance to member contamination and low-temperature fixing performance
Solution Approach 1:
Different regions of the toner particle are given different properties: the core has low Tg binder resin for fixing performance, while the shell has appropriate composition and structure to provide strength and prevent contamination. This local differentiation allows small particles to maintain both high resolution capability and running stability.
3Strength
If the shell layer is made relatively thick to improve durability and fixing performance, then the anti-stress properties are improved, but it becomes difficult to achieve low-temperature fixing performance and high image glossiness
Solution Approach 1:
The invention optimizes the shell layer thickness to a specific range (0.05-0.5 μm) and adjusts the core-to-shell size ratio to maintain appropriate proportions. This parameter optimization ensures the shell provides sufficient protection without being so thick as to interfere with heat transfer and low-temperature fixing performance.
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 superior low-temperature fixing performance, running performance, and cleaning performance, maintaining stability and preventing contamination, while ensuring high image glossiness and adhesion to transfer materials.
Implementation Method 1
polymerizing the polymerizable monomer contained in the particles of the polymerizable monomer composition
Implementation Method 2
in a micro-compression test in which a force is applied to a toner single particle at a loading rate of 9.8×10 -6 N/s
Data Source
Figure 1~2
Figure 3A~3B
Figure 4A~5
AI summary
A toner is provided which has toner particles and an inorganic fine powder; the toner particles being obtained by suspension polymerization using a specific polar resin. The toner is a toner in which; where, in displacement levels found in a micro-compression test in which a force is applied to a toner single particle at a loading rate of 9.8 x 10-6 N/sec to measure a displacement level (µm) at a point of time where the force has reached a maximum force of 4.90 x 10-4 N, the displacement level of the toner at a measurement temperature of 25 °C is represented by X(25) and the displacement level of the toner at a measurement temperature of 50 °C by X(50), and the number average particle diameter of the toner is represented by D (µm), the X(25), X(50) and D satisfies the relations: 0.10 = X(25)/D = 0.35 (1) 30 = [X(50)-X(25)]/X(25) x 100 = 150 (2).