Quasi-crystallized Polyester Toner for Low-Temp Fixing
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Solution Overview
Problem
Current toners face challenges in achieving simultaneous low-temperature fixability, excellent charging maintaining property, and scratch resistance, as existing solutions either compromise on one or more of these performance metrics due to compatibility issues between crystalline and amorphous polyester components.
Innovation Solution
A toner formulation incorporating a binder resin with a specific combination of amorphous and crystalline polyester, where the crystalline polyester is quasi-crystallized during cooling and crystallizes post-fixation, allowing for low-temperature fixability and enhanced scratch resistance through controlled molecular mobility and intermolecular forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If crystalline polyester is excessively compatible with binder resin, then low-temperature fixability is improved, but charging maintaining property deteriorates due to reduced charge quantity
Solution Approach 1:
The patent changes the physical state parameter of crystalline polyester from fully crystallized to quasi-crystallized (partially crystallized) to resolve the contradiction. This partial crystallization maintains compatibility with binder resin for low-temperature fixing while preventing excessive charge loss, thus improving charging maintaining property without sacrificing low-temperature fixability
2Reliability
If crystalline polyvinyl resin is used to improve charging maintaining property, then scratch resistance deteriorates due to suppressed wax exudation
Solution Approach 1:
The patent changes the crystallinity parameter of polyester from high crystallinity (crystalline polyvinyl resin) to low crystallinity (amorphous polyester with quasi-crystallized crystalline polyester). This reduces affinity for wax, promoting wax exudation and forming a wax layer on the image surface that provides scratch resistance while maintaining charging maintaining property
3Strength
If filler is added to improve scratch resistance, then low-temperature fixability deteriorates due to significant filler effect
Solution Approach 1:
The patent changes the crystallinity parameter of the polyester binder from conventional crystalline to quasi-crystallized state. This provides scratch resistance through controlled crystal growth during fixation without the negative impact of fillers on low-temperature fixability, achieving both scratch resistance and low-temperature fixability simultaneously
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 exhibits improved low-temperature fixability, excellent charging maintaining property, and scratch resistance, as the quasi-crystallized state of the crystalline polyester facilitates easy diffusion during fixation and crystal growth post-fixation, reducing friction and enhancing image stability.
Implementation Method 1
the crystalline polyester is quasi-crystallized during cooling and crystallizes post-fixation
Implementation Method 2
the crystalline polyester is quasi-crystallized during cooling and crystallizes post-fixation
Implementation Method 3
the quasi-crystallized state of the crystalline polyester facilitates easy diffusion during fixation
Data Source
AI summary
Provided is a toner containing a binder resin, wherein the binder resin contains an amorphous polyester and a crystalline polyester, and wherein, when the toner is used as a sample in differential scanning calorimetry (DSC) involving a first process of increasing a temperature from 20° C. to 180° C., a second process of decreasing the temperature from 180° C. to 20° C., and a third process of increasing the temperature from 20° C. to 180° C., DSC curves have a specific endothermic peak or exothermic peak derived from the crystalline polyester, and when a temperature of a maximum peak top of the endothermic peak in the DSC curve obtained through the first process is represented by T1 (° C.), and a temperature of a maximum peak top of the endothermic peak in the third DSC curve is represented by T2 (° C.), the Tl and the T2 satisfy the following expression (1).-1.≤T2-T1(1)