Emulsion Aggregation Toner Process Cycle Reduction
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Solution Overview
Problem
Existing emulsion/aggregation toner processes are time-consuming, often taking up to 24 hours, and attempts to shorten the process result in toner particles with inferior qualities such as poor charge performance and relative humidity sensitivity.
Innovation Solution
A process involving forming a mixture of gel latex, high Tg latex, wax, and colorant, aggregating, coalescing for 2-4 hours, treating with a pH of 8.5-10.5 at 50-75°C, and washing 2-4 times to produce toner particles with improved tribocharging tunability and reduced cycle time while maintaining desired qualities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the coalescence time is reduced to shorten the process, then the productivity is improved, but the toner particle quality deteriorates
Solution Approach 1:
The patent applies parameter changes by modifying the pH value (to 8.5-10.5) and temperature (50-75°C) during the coalescence stage. These parameter adjustments accelerate the coalescence kinetics, enabling high-quality toner particles to form in just 2-4 hours instead of the conventional 24 hours, thus resolving the contradiction between productivity and quality.
2Productivity
If the washing steps are reduced to shorten the process, then the productivity is improved, but the toner particle purity deteriorates
Solution Approach 1:
The patent extracts and removes specific impurities (residual surfactants, unreacted monomers, and byproducts) through optimized washing steps. By performing 2-4 targeted washing cycles with controlled pH conditions, the process efficiently removes contaminants while minimizing total washing time, thus improving productivity without sacrificing purity.
3Loss of time
If the aggregation and coalescence process is accelerated, then the loss of time is reduced, but the charge performance deteriorates
Solution Approach 1:
The patent applies preliminary action by conducting aggregation at controlled conditions before coalescence. This two-stage approach allows particles to first aggregate into nuclei, then coalesce under optimized pH and temperature conditions. This preliminary structuring ensures that even with reduced total time (2-4 hours), the charge performance is maintained because the aggregation framework is already established before the accelerated coalescence phase.
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 reduces cycle time by at least 25% for aggregation and coalescence and 40% for washing, while maintaining suitable A-zone and C-zone charge performance and image quality.
Implementation Method 1
aggregating toner particles in the mixture to form aggregated toner particles
Implementation Method 2
coalescing the aggregated toner particles for from about 2 hours to about 4 hours to form coalesced toner particles
Implementation Method 3
treating the coalesced toner particles with a pH treatment having a phi of from about 8.5 to about 10.5 at a temperature of from about 50° C. to about 75° C.
Data Source
AI summary
Disclosed herein are toner particles generated by emulsion/aggregation processes. The processes are conducted under conditions that shorten the time for coalescence and post-formation washing, thereby increasing efficiency of the processes as compared to conventional processes.