Crystalline Polyester Toner Low-Temperature Fixing Stability
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Solution Overview
Problem
Crystalline polyester toners exhibit excellent low-temperature fixing ability but suffer from poor durability and triboelectric stability under high-temperature, high-humidity conditions, making it difficult to use them in large amounts in electrophotography.
Innovation Solution
A toner formulation with a resin binder containing a polyester that is polycondensed from an alcohol component with 60% or more aliphatic diol and 80% or more aromatic dicarboxylic acid, with a crystallinity index of 0.6 to 1.5 and a glass transition temperature of 0°C to 40°C, or 0°C to 50°C, incorporating a polycyclic aromatic dicarboxylic acid compound, to enhance both low-temperature fixing ability and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If crystalline polyester is used as resin binder, then low-temperature fixing ability is improved, but durability and triboelectric stability under high-temperature high-humidity conditions deteriorate
Solution Approach 1:
The patent applies parameter changes by precisely controlling the glass transition temperature (0-40°C) and crystallinity index (0.6-1.5) of the polyester to achieve optimal balance between low-temperature fixing ability and high-temperature stability. By adjusting these physical parameters within specific ranges, the toner maintains both excellent low-temperature fixing performance and improved high-temperature durability.
Solution Approach 2:
The patent uses composite materials by combining polyester with specific ratios of aliphatic diol (60% or more) and aromatic dicarboxylic acid (80% or more) to create a resin binder that integrates the beneficial properties of both material components, achieving both low-temperature fixing ability and high-temperature stability.
2Temperature
If crystalline polyester is used in increased amount, then low-temperature fixing ability is improved, but blocking resistance deteriorates
Solution Approach 1:
The patent applies parameter changes by controlling the glass transition temperature within 0-40°C and crystallinity index within 0.6-1.5 to achieve the optimal balance point where low-temperature fixing ability is maximized while blocking resistance is maintained at acceptable levels.
Solution Approach 2:
The patent applies local quality by using specific local compositions of aliphatic diol (60% or more) and aromatic dicarboxylic acid (80% or more) within the polyester structure to create regions with different properties that work together to balance fixing ability and blocking resistance.
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 fixing ability while maintaining durability and triboelectric stability under high-temperature, high-humidity conditions, overcoming the limitations of crystalline polyester toners.
Implementation Method 1
the polyester is obtained by polycondensing an alcohol component containing 60% by mol or more of an aliphatic diol having 3 to 10 carbon atoms and a carboxylic acid component containing 80% by mol or more of an aromatic dicarboxylic acid compound
Implementation Method 2
a crystalline polyester has excellent low-temperature fixing ability but has poor durability... it is difficult to use the crystalline polyester alone as a resin binder
Implementation Method 3
triboelectric stability under high-temperature high-humidity conditions
Data Source
AI summary
A toner for electrophotography containing a resin binder and a colorant, wherein the resin binder contains a polyester in an amount higher than 50% by weight of the resin binder, wherein the polyester is obtained by polycondensing an alcohol component containing 60% by mol or more of an aliphatic diol having 3 to 10 carbon atoms and a carboxylic acid component comprising 80% by mol or more of an aromatic dicarboxylic acid compound, the polyester having an index of crystallinity of from 0.6 to 1.5, and a glass transition temperature of 0° C. or more and less than 40° C. The toner for electrophotography of the present invention can be used for, for example, developing electrostatic latent images formed in electrophotography, electrostatic recording method, electrostatic printing method, or the like.