Toner Production via Rapid Cooling and Crystalline Microdomain Segmentation
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Solution Overview
Problem
There is a trade-off between low-temperature fixability and storability in toners, as enhancing low-temperature fixability through the use of crystalline substances compromises storability due to crystalline substance outmigration at high temperatures, leading to toner blocking and reduced storage quality.
Innovation Solution
A method for producing toners that involves setting a temperature above the crystallization temperature and glass transition temperature of the crystalline substance and binder resin, followed by rapid cooling and holding at a specific temperature range to achieve dispersion and high crystallinity, preventing crystalline substance outmigration and maintaining storability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the amount of crystalline substance is increased to enhance low-temperature fixability, then low-temperature fixability is improved, but storability deteriorates due to crystalline substance outmigration
Solution Approach 1:
The crystalline substance is divided into numerous microdomains dispersed throughout the toner interior, with each microdomain being a small, isolated crystalline region. This segmentation prevents the crystalline substance from migrating to the surface while maintaining the plasticizing effect within each microdomain for low-temperature fixability.
Solution Approach 2:
The crystalline substance is distributed non-uniformly as dispersed microdomains throughout the toner interior rather than being concentrated in one location. This local distribution ensures that the plasticizing effect is available where needed for fixing while preventing surface migration that would harm storability.
2Temperature
If the cooling rate is increased to disperse crystalline substance in toner interior, then low-temperature fixability is improved, but manufacturing complexity increases
Solution Approach 1:
The patent specifies a quantitative parameter for the cooling rate (at least 5.0°C/min) to achieve the desired dispersion of crystalline substance. By defining a specific parameter threshold, the process becomes controllable and reproducible without requiring excessively complex manufacturing equipment.
3Reliability
If the degree of crystallinity is increased to improve storability, then storability is improved, but low-temperature fixability deteriorates due to reduced dispersion
Solution Approach 1:
The crystalline substance is segmented into numerous small microdomains dispersed throughout the toner, rather than forming large aggregated crystals. This segmentation maintains high degree of crystallinity within each microdomain for storability while ensuring widespread distribution for low-temperature fixability.
Solution Approach 2:
Instead of increasing crystallinity through large-scale crystal growth in one dimension, the patent achieves high crystallinity through numerous small crystalline microdomains distributed throughout the three-dimensional toner interior. This dimensional approach allows both high crystallinity and good dispersion to coexist.
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 method enhances low-temperature fixability while maintaining excellent storability by dispersing crystalline substances within the toner interior, forming numerous microdomains that suppress outmigration and improve crystallinity, allowing for effective coexistence of low-temperature fixability and storability.
Implementation Method 1
cooling the dispersion from the TA to a temperature equal to or lower than the Tg at a cooling rate of at least 5.0°C./min
Implementation Method 2
holding the dispersion in a temperature range of at least Tg−10(° C.) and not more than Tg+10(° C.) for at least 30 min
Implementation Method 3
The crystalline substance melts at the melting point exhibited by such a material and plasticizes the binder resin used in the toner
Data Source
AI summary
A method for producing a toner containing a toner particle containing a binder resin, a colorant and a crystalline substance, wherein the method includes the steps of: (I) setting a temperature of a dispersion, in which a coloring particle is dispersed with an aqueous medium, to TA(° C.), which is higher than the higher of a crystallization temperature Tc(° C.) of the crystalline substance and a glass transition temperature Tg(° C.) of the coloring particle, the coloring particle containing the binder resin, the colorant and the crystalline substance; (II) cooling the dispersion from the TA to a temperature equal to or lower than the Tg at a cooling rate of at least 5.0° C./min after the step (I); and (III) holding the dispersion in a temperature from Tg−10 to Tg+10 for at least 30 min after the step (II).