Crystalline Polyester Toner Core Shell Structure for Low Temperature Fixing
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Solution Overview
Problem
Toner particles manufactured by the kneading and pulverization method face challenges such as large particle size, irregular shape, wide particle size distribution, contamination, reduced fluidity, and charging properties, leading to inadequate low temperature fixing and heat resistant preservability.
Innovation Solution
A toner with a core of crystalline polyester and a shell formed on the surface, where the aspect ratio of crystalline polyester is between 1 to 3 and the average length of the longitudinal diameter is within 10 nm to 500 nm, ensuring the crystalline polyester does not protrude into the shell, maintaining the toner's surface integrity and performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the crystalline polyester resin is heated to the melting point or higher during manufacturing, then the low temperature fixing property is improved, but the resin partially dissolves with the amorphous resin and forms crystals that protrude into the toner surface, causing contamination and reduced fluidity
Solution Approach 1:
The patent applies parameter changes by precisely controlling the melting point of the crystalline polyester resin through selection of specific resin types (e.g., polycondensation products of polyols and polyacids with controlled molecular weight and structure). This allows the resin to melt at the fixing temperature to provide low temperature fixing property, while preventing excessive dissolution and crystal formation that would compromise surface integrity. The patent also controls the aspect ratio and size distribution of crystalline polyester particles to maintain surface smoothness.
2Reliability
If wax is added to improve fixing property, then the mold releasing effect is obtained, but the toner is likely to be broken at the wax interface during pulverizing, causing wax to be present on the toner surface and leading to adhering and filming
Solution Approach 1:
The patent extracts the harmful wax component from the toner formulation entirely. Instead of adding wax as a mold-release agent, the invention uses a crystalline polyester resin with controlled melting properties that provides the necessary fixing performance without the harmful adhesion and filming issues caused by wax. This eliminates the source of the harmful factor rather than managing its presence.
Solution Approach 2:
The patent changes the chemical composition parameters by replacing wax-based mold-release agents with crystalline polyester resins having specific melting points and molecular structures. This parameter change maintains the mold-release function while eliminating the harmful adhesion properties of wax, as the crystalline polyester forms a stable, non-adhering surface layer.
3Manufacturing precision
If the particle size is reduced for high quality output, then the image quality is improved, but the toner has wide particle size distribution and irregular shape, reducing manufacturing precision
Solution Approach 1:
The patent uses composite materials by combining crystalline polyester resin particles with specific inorganic fillers and surface treatment agents. This composite approach allows precise control over particle size distribution and shape regularity while maintaining the core functionality of the crystalline polyester for low temperature fixing. The composite structure enables narrow size distribution and regular spherical shapes through controlled aggregation and surface modification.
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 solution provides excellent low temperature fixing property, heat resistant preservability, and stable image quality by preventing the crystalline polyester from contaminating the equipment and maintaining the toner's fluidity and charging properties.
Implementation Method 1
the crystalline polyester resin contained in the core is heated in the manufacturing step of the toner to the melting point of the crystalline resin or higher, partially dissolves with the amorphous resin contained in the shell
Implementation Method 2
the crystalline polyester resin contained in the core is heated in the manufacturing step of the toner to the melting point of the crystalline resin or higher
Data Source
AI summary
A toner has excellent low temperature fixing property, heat resistant preservability, and stable image quality. The toner contains a core including a crystalline polyester, and a shell formed on a surface of the core. An aspect ratio of the crystalline polyester in the toner is within a range from 1 to 3, and an average length of a longitudinal diameter of the crystalline polyester is within a range from 10 nm to 500 nm.