Crystalline Polyester 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 storage stability, particularly when using crystalline resins, which can lead to decreased glass transition temperatures and poor dispersibility of resin components, resulting in non-uniform electric charge and blocking during storage. Additionally, methods proposed in prior art require new equipment, reducing productivity and increasing costs.
Innovation Solution
The toner incorporates a crystalline polyester resin comprising an alicyclic dibasic acid, terephthalic acid, and isophthalic acid as acid components, compounded in a specific amount within the toner particle, allowing for both low-temperature fixability and storage stability without the need for new equipment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a melting point of resin is lowered to improve low-temperature fixing performance, then fixing temperature is reduced, but glass transition temperature is lowered which deteriorates storage stability
Solution Approach 1:
The patent uses a composite resin system combining amorphous resin (providing low-temperature fixability) and crystalline resin (providing storage stability). The crystalline resin particles are dispersed in the amorphous resin matrix, creating a composite material that exhibits both low melting point for easy fixing and high glass transition temperature for storage stability. This resolves the contradiction by integrating two materials with complementary properties.
Solution Approach 2:
The patent creates local quality differentiation by forming a core-shell structure where the center portion contains amorphous resin with low melting point for fixing, while the outer layer contains crystalline resin with high glass transition temperature for storage stability. This spatial differentiation allows different regions to fulfill different functional requirements simultaneously.
2Temperature
If crystalline resin and non-crystalline resin are melt-kneaded to achieve low-temperature fixability, then fixing performance is improved, but dispersibility decreases leading to non-uniform electric charge
Solution Approach 1:
The patent applies preliminary action by pre-dispersing crystalline resin particles into the amorphous resin matrix before complete solidification. The crystalline resin is introduced as fine particles during the cooling phase after melt-kneading, ensuring uniform distribution before the matrix solidifies. This preliminary dispersion prevents aggregation and maintains charge uniformity while achieving low-temperature fixability.
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
This configuration enables the toner to achieve excellent low-temperature fixability and storage stability while utilizing existing equipment, thereby maintaining cost-effectiveness and productivity.
Implementation Method 1
use of a crystalline resin having a sharp melt property has been considered
Implementation Method 2
a glass transition temperature of a toner is lowered, which deteriorates a storage stability
Data Source
AI summary
A toner for developing an electrostatic charge image, comprising a toner particle and an external additive, the toner particle comprising a binder resin containing a crystalline polyester resin, a colorant, and a release agent, the crystalline polyester resin comprising an alicyclic dibasic acid, a terephthalic acid, and an isophthalic acid as acid components and being contained in the toner particle in an amount of 4 to 8% by mass.