Core-Shell Toner Particles Gloss Control
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Solution Overview
Problem
Polyester EA ultra low melt toners exhibit high peak gloss, which is undesirable for imaging applications, limiting their fusing properties and performance.
Innovation Solution
A process involving the formation of core-shell toner particles by contacting amorphous and crystalline resins in an aqueous emulsion, with optional colorants, surfactants, and waxes, followed by aggregation, coalescence, and crosslinking using water-soluble initiators to reduce gloss and enhance fusing properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polyester EA ultra low melt toners are prepared using amorphous and crystalline polyester resins, then excellent fusing properties including crease minimum fixing temperature and fusing latitude are achieved, but peak gloss becomes unacceptably high
Solution Approach 1:
The patent applies local quality by creating a core-shell structure where the core contains crystalline polyester resin for fusing performance while the shell contains amorphous polyester resin to control and reduce peak gloss. This spatial differentiation of material properties allows simultaneous optimization of fusing properties and gloss control.
Solution Approach 2:
The patent uses composite materials by combining crystalline polyester resin and amorphous polyester resin in a single toner particle structure. The crystalline resin provides excellent fusing properties while the amorphous resin modifies the surface characteristics to reduce peak gloss, achieving a synergistic effect that neither material could achieve alone.
2Reliability
If a crosslinked core-shell structure is formed to reduce peak gloss, then imaging performance is enhanced, but the manufacturing process becomes more complex
Solution Approach 1:
The patent applies segmentation by dividing the toner particle formation process into distinct stages: first forming the core with crystalline resin, then coating with amorphous resin, and finally crosslinking the shell. This segmentation allows each stage to be optimized independently while achieving the desired core-shell structure with controlled gloss properties.
Solution Approach 2:
The patent uses preliminary action by pre-forming the core-shell structure before the crosslinking step. The core is formed first with crystalline resin, then the amorphous resin coating is applied, and only after this preliminary structure is in place is the crosslinking initiated to lock in the desired properties and prevent resin migration.
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 results in toner particles with reduced peak gloss, improved fusing properties, and enhanced imaging performance by creating a crosslinked core-shell structure that prevents crystalline resin migration and controls gloss levels.
Implementation Method 1
contacting the larger aggregates with an emulsion including the at least one amorphous resin or a different at least one amorphous resin, or both, to form a resin coating over the larger aggregates; coalescing the larger aggregates within the resin coating and simultaneously or subsequently crosslinking either the larger aggregates or the resin coating or both
Implementation Method 2
contacting at least one amorphous resin with at least one crystalline resin in an aqueous emulsion to form small particles
Data Source
AI summary
Toner particles are provided which may, in embodiments, include a core and a shell formed in situ. The resins utilized to form the core, the shell, or both, may be contacted with a water soluble initiator. The resin, in embodiments present in the shell, cross-links at a temperature near the temperature for coalescence, and may prevent a crystalline resin in the core from migrating to the toner surface.