Toner Particles Coalescing Process for High Circularity
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Solution Overview
Problem
Conventional toner production methods often result in non-spherical particles, leading to defects such as toner filming and unstable image quality due to the use of non-spherical toners.
Innovation Solution
A process involving melt-mixing of amorphous and crystalline resins with optional waxes and colorants, followed by pelletizing, grinding, and coalescing with deionized water and surfactants to achieve toner particles with a circularity of 0.92 to 0.999, ensuring spherical shape.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If conventional pulverizing processes are used to produce toner particles, then production simplicity is maintained, but particle sphericity deteriorates resulting in non-spherical particles with circularity below 0.92
Solution Approach 1:
The invention changes the physical-chemical parameters of the toner particles by conducting a coalescence process at elevated temperatures (50-100°C) in the presence of water and surfactants. This thermal treatment causes the particles to fuse and reform into spherical shapes, transforming the particle morphology from irregular to spherical without requiring complete re-synthesis of the toner material.
Solution Approach 2:
The invention introduces water and surfactants as intermediary substances to facilitate the coalescence process. The surfactant acts as a mediator that reduces surface tension and enables the toner particles to coalesce into spherical shapes during the heating process, achieving high sphericity without direct mechanical intervention.
2Reliability
If non-spherical toner particles are used, then production costs are reduced, but image quality stability deteriorates due to toner filming defects
Solution Approach 1:
The invention changes the particle shape parameter by treating irregular toner particles with heat (50-100°C) in the presence of water and surfactants. This coalescence treatment causes the particles to reshape into spheres with circularity of 0.92 or higher, eliminating the toner filming defects that cause image quality instability while using a simple post-processing step rather than expensive alternative production methods.
3Shape
If a coalescence process with water and surfactants is implemented, then particle circularity is improved to 0.92-0.999, but process complexity increases
Solution Approach 1:
The invention achieves high particle circularity (0.92-0.999) by controlling the parameters of the coalescence process: temperature (50-100°C), presence of water and surfactant, and treatment time. These parameter controls enable spherical particle formation through a relatively simple one-step thermal treatment process that can be integrated into existing toner production lines without requiring complex equipment modifications.
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 process produces toner particles with high circularity, preventing toner filming and ensuring stable image quality by maintaining spherical shape, thus addressing the defects associated with non-spherical toners.
Implementation Method 1
coalescing the toner particles by heating the mixture to a temperature of from about 50° C. to about 100° C.
Implementation Method 2
contacting the toner particles with deionized water and at least one surfactant
Data Source
AI summary
The present disclosure provides processes for producing toner particles, and toner particles produced by such processes. The processes of the present disclosure combine melt-mixing and grinding of toner components to produce toner particles, followed by a coalescing treatment which provides toner particles having desirable spherical properties.