Segmented Toner Particles for High Color Density and Erasability
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Solution Overview
Problem
Existing electrophotographic toner production methods, such as melt-kneading, face challenges in achieving a balance between fixability, color developability, and erasability due to the inhibition of leuco dye and color developer dispersion in the binder resin, leading to decreased color density and the need for specific resins with low color erasing action.
Innovation Solution
A method involving the separate preparation of fine particles containing a binder resin, color developable compounds, and color erasers, followed by aggregation and fusion, allows for the encapsulation of these components, enabling the production of toner particles with improved color density and erasability without the need for resins with low color erasing action.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a kneading pulverization method is used to melt-knead the color developable compound and color developer with the binder resin, then the toner components are uniformly dispersed, but the leuco dye and color developer reaction is inhibited and the developed color density decreases
Solution Approach 1:
The invention divides the toner into two distinct particle populations: colorless particles containing the binder resin and leuco dye, and colored particles containing the color developer. This segmentation prevents the leuco dye and color developer from being uniformly dispersed and reacting during kneading, thereby maintaining high developed color density while achieving uniform distribution of toner components through the dual-population structure.
2Manufacturing precision
If a binder resin with low color erasing action is used, then the developed color density is maintained during kneading, but the erasability of the toner image is reduced
Solution Approach 1:
By separating the leuco dye into colorless particles and the color developer into colored particles, the invention enables the use of binder resins with strong color erasing action (such as polyester resins) without compromising developed color density. The segmented structure ensures that the color developer particles remain intact and reactive during kneading, while the binder resin's color erasing action only affects the leuco dye in the colorless particles, which do not contribute to the developed image density.
3Reliability
If polyester resin or styrene-acrylic resin is used as binder resin, then excellent fixability is achieved, but the resin exhibits color erasing action that decreases developed color density during kneading
Solution Approach 1:
The invention enables the use of polyester resin or styrene-acrylic resin as binder resin by segmenting the toner into colorless particles (containing the resin and leuco dye) and colored particles (containing color developer). This segmentation protects the color developer from the resin's color erasing action during kneading, allowing these resins with excellent fixability to be used without compromising developed color density.
4Stability of the object's composition
If high shearing force is applied during kneading, then the toner components are thoroughly mixed, but the reaction between leuco dye and color developer is inhibited
Solution Approach 1:
The invention segments the toner into separate colorless and colored particle populations, preventing direct contact and reaction between the leuco dye and color developer during high shearing force kneading. This segmentation allows thorough mixing and uniform distribution of toner components under high shear conditions while maintaining high color developability, as the color developer remains encapsulated in intact colored particles.
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
This approach maintains high color density and allows for rapid color erasure and restoration, enhancing the environmental and economic efficiency of toner recycling by enabling the reuse of printed materials.
Implementation Method 1
a toner which contains a color developable compound and a color developer and the color of which can be erased by heating
Implementation Method 2
by heating a sheet of printed paper to 100 to 200° C. for about 1 to 3 hours, the color of the printed image can be erased
Data Source
AI summary
According to one embodiment, a toner includes at least one encapsulated particle containing a color developable compound, color developer and a color eraser and polymeric particles. The at least one encapsulated particle and the polymeric particles being aggregated and fused in dispersion liquid.