Toner Resin Crystallization for Fixing and Storage Stability
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Solution Overview
Problem
Conventional toners face challenges in achieving both high-speed fixing performance, long-term storage stability, and high-temperature high-humidity storage stability while maintaining uniform gloss, due to issues with crystalline and amorphous polyester resin compatibility and heat-resistant storability.
Innovation Solution
A toner is developed by combining a crystalline polyester resin with a nucleating agent segment and an amorphous polyester resin having an aliphatic hydrocarbon functional group, where the crystalline resin forms a crystalline state with the functional group at room temperature, suppressing plasticization and enhancing heat-resistant storability, and rapidly plasticizing during hot-melting for improved fixability and gloss uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If an amorphous polyester resin with bonded aliphatic hydrocarbon segments is used to improve low-temperature fixability, then fixing performance is enhanced, but heat-resistant storability is impaired due to gradual plasticization at high temperature
Solution Approach 1:
The invention divides the resin system into two distinct segments: a crystalline polyester resin segment (providing heat-resistant storability) and an amorphous polyester resin segment with aliphatic hydrocarbon segments (providing low-temperature fixability). This segmentation allows each component to perform its specialized function without interfering with the other's stability properties.
Solution Approach 2:
The invention creates a composite resin system combining crystalline polyester resin and amorphous polyester resin with aliphatic hydrocarbon segments in specific proportions (crystalline: 10-50 wt%, amorphous: 50-90 wt%). This composite structure enables the toner to achieve both low-temperature fixability and heat-resistant storability simultaneously.
2Temperature
If compatibility between crystalline resin and amorphous resin is excessively high to improve low-temperature fixability, then fixing performance is enhanced, but heat-resistant storability decreases and sharp melt property is lost
Solution Approach 1:
The invention optimizes the compatibility parameter between crystalline and amorphous resins by controlling the aliphatic hydrocarbon segment content in the amorphous resin and the molecular weight ratios. This parameter optimization ensures sufficient compatibility for low-temperature fixability while maintaining enough distinction to preserve heat-resistant storability and sharp melt property.
3Temperature
If amorphous polyester segments are plasticized by aliphatic hydrocarbon segments of high molecular mobility during storage, then low-temperature fixability is enhanced, but gloss unevenness arises during hot melting
Solution Approach 1:
The invention creates local quality differentiation within the resin system: the crystalline polyester resin maintains a rigid, ordered structure that prevents excessive plasticization and viscosity variation, while the amorphous polyester resin with aliphatic hydrocarbon segments provides localized flexibility for low-temperature fixability. This local quality control ensures uniform gloss during hot melting.
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 long-term storage stability, high-temperature high-humidity storage stability, and uniform gloss, while maintaining good fixing performance in high-speed printing by controlling the crystallization and plasticization of the resin components.
Implementation Method 1
the crystalline resin forms a crystalline state with the functional group at room temperature, suppressing plasticization
Implementation Method 2
rapidly plasticizing during hot-melting for improved fixability and gloss uniformity
Data Source
AI summary
Provided is a toner having excellent long-term storage stability and exhibiting both low-temperature fixability and uniform gloss in high-speed printing. A toner has a toner particle that contains a crystalline polyester resin A, an amorphous polyester resin B and a colorant, wherein the crystalline polyester resin A has a polyester molecular chain having a nucleating agent segment at the terminal end thereof, and an SP value Sa ((cal/cm3)1/2) of the crystalline polyester resin A ranges from 9.00 to 11.50, and the amorphous polyester resin B has a specific functional group.