Emulsion Aggregation Toner for Particle Size Control
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Solution Overview
Problem
Existing toner compositions for electrophotographic printers often rely on physical processes that are inefficient and lack control over particle size and circularity, leading to suboptimal performance in forming high-quality images.
Innovation Solution
A chemically processed toner method involving the formation of polyester, pigment, and release agent dispersions with specific pH, particle size, and dispersant ratios, followed by agglomeration and heating to achieve toner particles with controlled size and circularity, using an emulsion aggregation method.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If physical processes are used to form toner particles, then the process is simpler, but particle size and circularity control are poor
Solution Approach 1:
The invention changes the fundamental parameter of the formation process from physical mechanical processes to chemical processes. By using emulsion aggregation with controlled polymerization reactions, the method achieves precise control over particle size (3-15 microns) and circularity (0.90-1.0) through chemical reaction conditions rather than mechanical forces.
Solution Approach 2:
The invention replaces mechanical/physical processes with chemical processes. Instead of using mechanical grinding, screening, or classification to control particle size and shape, the method uses chemical emulsion aggregation where polymer particles naturally form with controlled morphology through chemical reaction parameters.
2Manufacturing precision
If chemical processes are used to form toner particles, then particle size and circularity control are improved, but the process becomes more complex
Solution Approach 1:
The invention segments the manufacturing process into distinct chemical stages: forming polyester dispersion with controlled molecular weight and acid value, preparing pigment dispersion with specific P/D ratios, preparing release agent dispersion with controlled RA/D ratios, and finally agglomerating these dispersions. Each stage is independently optimized to achieve overall process control.
Solution Approach 2:
The method controls multiple parameters at each stage: polyester acid value (5-50), molecular weight (2500-40000), dispersion pH (6-8), pigment to dispersant ratio (1:1 to 8:1), release agent to dispersant ratio (1:1 to 15:1), and final particle size (3-15 microns). This systematic parameter control makes the complex process manageable and repeatable.
3Manufacturing precision
If emulsion aggregation method is used, then toner particle circularity is enhanced, but manufacturing steps increase
Solution Approach 1:
The invention combines multiple dispersions (polyester, pigment, and release agent) into a single agglomeration step. By preparing all components as stable dispersions with controlled properties and then agglomerating them together, the method achieves high circularity particles in an integrated process rather than through multiple separate operations.
Solution Approach 2:
The method performs preliminary preparation of each component as a stable dispersion with controlled properties before the final agglomeration step. The polyester dispersion is pre-formed with controlled molecular weight and acid value, pigment and release agent are pre-dispersed with optimal ratios, which enables the final agglomeration to proceed efficiently with high circularity output.
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 produces toner particles with a mean size of 3 to 15 microns and an average circularity of 0.90 to 1.0, enhancing image quality and stability in electrophotographic printers by controlling the final toner particle size and geometry.
Implementation Method 1
combining the polyester in an organic solvent that is at least partly miscible with water and introducing water
Implementation Method 2
removing substantially all of the organic solvent
Implementation Method 3
form a pigment dispersion in the presence of a dispersant wherein the dispersant contains a hydrophilic component and a hydrophobic component
Implementation Method 4
the dispersant contains a hydrophilic component and a hydrophobic component
Implementation Method 5
combine the polyester dispersion and the pigment and the release agent dispersion and agglomerate in the presence of agglomerating agent
Implementation Method 6
agglomerate in the presence of agglomerating agent, along with heating
Data Source
AI summary
The present disclosure relates to chemically processed toner. The toner may be prepared by an emulsion aggregation method by forming a polyester dispersion wherein the polyester has an acid value of about 5 to about 50 and a particle size of about 50 to about 500 nanometers. The polyester dispersion may then be combined with a pigment and/or release agent dispersion wherein the pigment and/or release agent dispersion may contain a dispersant. This may then be followed by heating and recovering agglomerated toner particles wherein the toner particles may have a mean particle size of about 3 to about 15 microns and an average degree of circularity of between about 0.90 to about 1.0.