Crystalline Polyester Toner with Epoxy Modifier for Offset Control
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Solution Overview
Problem
Existing toners using crystalline polyester resins face challenges in achieving a wide fixing temperature range, high glossiness, and sufficient heat-resistant storage stability due to issues with crystallinity and high-temperature offset, particularly when combined with amorphous polymers.
Innovation Solution
A toner composition with a binder resin primarily composed of crystalline polyester, optimized through specific viscoelastic properties and an annealing treatment to maintain crystallinity, ensuring a wide fixing range and high glossiness while suppressing high-temperature offset.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a crystalline polyester resin is used to achieve low-temperature fixability, then the sharp melt property is improved, but the high-temperature offset resistance deteriorates due to insufficient elasticity
Solution Approach 1:
The patent uses a composite binder resin system combining crystalline polyester (providing sharp melt property for low-temperature fixing) with amorphous polyester and epoxy compound (providing elasticity and high-temperature offset resistance). This composite approach allows both low-temperature fixability and high-temperature stability to be achieved simultaneously.
Solution Approach 2:
The patent modifies the crystalline polyester through epoxy compound addition to change its physical parameters. The epoxy compound reacts with hydroxyl groups of the polyester, altering the molecular structure to improve elasticity while maintaining the crystalline melting characteristics, thereby resolving the contradiction between sharp melting and high-temperature elasticity.
2Reliability
If crystalline polyester is mixed with amorphous polymer to improve elasticity, then high-temperature offset resistance is improved, but the crystallinity is reduced leading to decreased low-temperature fixability
Solution Approach 1:
Instead of simply mixing crystalline and amorphous polymers, the patent chemically modifies the crystalline polyester by adding epoxy compound. This changes the molecular parameters to provide elasticity without destroying the crystalline structure, maintaining both high-temperature resistance and low-temperature fixing capability.
Solution Approach 2:
The epoxy compound acts as an intermediary that bridges the crystalline polyester and amorphous polyester components. It reacts with the crystalline polyester to introduce elastic characteristics while preserving the crystalline melting behavior, serving as a mediator that reconciles the conflicting requirements.
3Adaptability or versatility
If block copolymer is used to combine crystalline and amorphous polyester, then fixing latitude is improved, but the content of crystalline polyester is reduced leading to insufficient sharp melt effect
Solution Approach 1:
The patent changes the approach from physical blending (block copolymer) to chemical modification (epoxy addition). This allows higher content of crystalline polyester to be maintained while still achieving the desired elasticity and fixing latitude through the chemical reaction that introduces flexible segments without reducing crystalline content.
4Ease of manufacture
If heating step at melting point of crystalline polyester is applied in manufacturing, then the binder resin is formed, but the crystallinity is degraded due to thermal history
Solution Approach 1:
The patent performs preliminary crystallization of the polyester resin before the high-temperature binding step. By pre-forming the crystalline structure at lower temperatures and then adding the epoxy compound at controlled temperatures, the crystallinity is preserved despite subsequent heating during toner formation.
Solution Approach 2:
The epoxy compound serves as a protective intermediary that allows the crystalline structure to survive high-temperature processing. The reaction between epoxy and hydroxyl groups creates a protective network that maintains crystallinity even when heating to melting point is required for manufacturing.
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, heat-resistant storage stability, and high-quality image glossiness, effectively addressing the limitations of previous toner formulations.
Implementation Method 1
a method which enables a binder resin to have a sharper melt property has been known as one of effective methods. Since molecular chains of a crystalline polyester resin are regularly aligned, the crystalline polyester resin has not a clear glass transition temperature and is not likely to be softened up to its crystalline melting point.
Implementation Method 2
optimized through specific viscoelastic properties and an annealing treatment to maintain crystallinity
Data Source
AI summary
In a toner formed of toner particles which include a colorant, a wax, and a binder resin containing a crystalline resin (a) primarily composed of a polyester, the crystalline resin has an endothermic peak temperature (Tp) in a range of 50° C. to 80° C., and in a viscoelasticity measurement of the toner, G″(Tp−10) is in a range of 5.0×107 to 5.0×108 Pa, G″(Tp+10) is in a range of 5.0×105 to 5.0×106 Pa, and G″(Tp−20), G″(Tp−10), G″(Tp+10), and G″(Tp+30) satisfy specific relationships.