Toner Process Coalescence Temperature Control
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Solution Overview
Problem
Toner compositions with high pigment loading, particularly black pigments, exhibit reduced charging and increased dielectric loss, leading to lower transfer efficiency and degraded image quality due to conductive pathways formed within the toner particles.
Innovation Solution
Reducing the coalescence temperature during the aggregation/coalescence process and employing quench cooling to produce toners with lower dielectric loss, improved tribo charging, and increased pigment loading, while maintaining or improving other benchmark evaluations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If higher amounts of black pigment are added to toners to increase color density and blackness, then coloring performance is improved, but dielectric loss increases and charging ability decreases
Solution Approach 1:
The patent changes the coalescence temperature parameter during toner formation, using a lower coalescence temperature to reduce dielectric loss while maintaining high pigment loading. This parameter change allows the toner to achieve both high color density and low dielectric loss by controlling the thermal history and morphology development during the coalescence process.
2Illumination intensity
If higher amounts of black pigment are added to toners to improve color density, then coloring performance is improved, but transfer efficiency decreases due to reduced charging
Solution Approach 1:
The patent employs parameter changes in the coalescence temperature to simultaneously improve charging ability and maintain high pigment loading. By optimizing the coalescence temperature, the toner achieves better tribocharging performance, which directly improves transfer efficiency while preserving the high color density provided by increased black pigment content.
3Loss of energy
If coalescence temperature is reduced during toner formation, then dielectric loss decreases and charging improves, but the process deviates from conventional high-temperature coalescence
Solution Approach 1:
The patent deliberately changes the coalescence temperature parameter from conventional high temperatures to lower temperatures. This non-conventional parameter change enables reduced dielectric loss and improved charging performance. The lower coalescence temperature process, while deviating from conventional methods, provides superior electrical properties that justify the process modification.
4Loss of energy
If quench cooling is applied after coalescence, then dielectric loss is further reduced and charging is improved, but additional process complexity is introduced
Solution Approach 1:
The patent utilizes phase transition control through quench cooling after coalescence. The rapid cooling induces specific phase transitions in the toner matrix that lock in the desired morphology and minimize dielectric loss. This phase transition approach, combined with lower coalescence temperature, achieves superior electrical properties despite the added process step.
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 results in toners with significantly reduced dielectric loss, improved tribo charging, and enhanced transfer efficiency, approaching the performance of non-hyperpigmented toners, with sodium ion content reduced to minimize conductive domains at the toner surface.
Implementation Method 1
The particles can be coalesced at a temperature lower than the melting point of said optional crystalline resin and said wax
Implementation Method 2
the coalesced particles can be quench cooled or both. The resulting toner can exhibit lower dielectric loss as compared to a toner produced similarly but coalesced at a temperature higher than the melting point of said crystalline resin and wax; not quench cooled; or both
Data Source
AI summary
The present disclosure describes a toner produced using a coalescing temperature lower than the melting point of a wax in the toner, quench cooling or both. The resulting toners can exhibit reduced dielectric loss and improved tribo charging.