Erasable Toner Segmentation for Color Density and Erasing Speed
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Solution Overview
Problem
Existing electrophotographic toners face challenges in achieving high color development density while maintaining environmental sustainability, as strong de-coloring agents reduce color density, and weak de-coloring agents slow down the erasing process, necessitating prolonged heating.
Innovation Solution
A toner composition comprising a mixture of colored particles with a color former compound, color developer agent, and binder resin, and de-coloring particles with a higher melting point than the fixing temperature, allowing for separate color development and erasing functions, where only the colored particles are melted during fixing and both are melted during erasing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a strong de-coloring agent with basic properties is used, then the de-coloring action is enhanced, but the developed color density is decreased or the color is lost
Solution Approach 1:
The toner is divided into two distinct particle types: colored particles containing color former compound and binder resin, and de-coloring particles containing only de-coloring agent. This segmentation allows each particle type to perform its specific function independently - colored particles maintain color density during fixing while de-coloring particles provide achromatizing action during erasing, thereby resolving the contradiction between strong de-coloring action and color density maintenance.
Solution Approach 2:
Different regions of the toner system are assigned different functional properties. The colored particles are designed with specific composition (color former compound + binder resin) to maintain color density, while de-coloring particles have different composition (de-coloring agent only) to provide erasing action. This local differentiation of quality allows simultaneous achievement of high color density and effective de-coloring without mutual interference.
2Manufacturing precision
If a weak de-coloring agent is used, then the developed color density is increased, but the erasing speed becomes low and prolonged heating is required
Solution Approach 1:
By segmenting the toner into separate colored particles and de-coloring particles, the system can independently optimize each component: colored particles use weak de-coloring agents to maintain high color density, while de-coloring particles use agents specifically optimized for rapid erasing action. This eliminates the compromise required when using a single mixed toner composition.
Solution Approach 2:
The de-coloring particles act as functional copies dedicated solely to the erasing function, allowing the system to replicate the de-coloring action without the interfering presence of color former compounds. This pure-function approach enables rapid erasing speed while the colored particles maintain their color density integrity.
3Ease of manufacture
If color former compound, color developer agent and de-coloring agent are melt-kneaded together, then the toner is produced in a single process, but the developed color density is decreased due to simultaneous interaction
Solution Approach 1:
Instead of melt-kneading all components together, the process segments the toner production into two separate steps: first producing colored particles (color former compound + binder resin), then producing de-coloring particles (de-coloring agent only), and finally mixing them. This segmentation prevents the harmful simultaneous interaction between color developer agent and de-coloring agent during the color development process, thereby maintaining high color density while still achieving complete functionality.
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 developed color density and enables rapid and efficient color erasure, ensuring excellent color developing and erasing properties without compromising on environmental efficiency.
Implementation Method 1
only the colored particles are melted during fixing
Implementation Method 2
both are melted during erasing
Implementation Method 3
the de-coloring particles are not melted, and therefore do not affect the color development mechanism. Accordingly, the developed color state is maintained. On the other hand, in the erasing temperature range, the colored particles and the de-coloring particles are both melted
Data Source
AI summary
An erasable toner is prepared by mixing colored particles containing at least a color former compound, a color developer agent and a binder resin with de-coloring particles having a melting point higher than the fixing temperature of the colored particles. By using this toner, a colored image is formed by electrostatically transferring a toner image onto a medium, and heating the toner image at a temperature lower than the melting point of the de-coloring particles to form a fixed toner image in a color developed state, and the color of the fixed image is erased by heating the image to a temperature not lower than the melting point of the de-coloring particles. In this toner, the color developing function and the color erasing function are assigned to different particles so that the functions are separated from each other, and therefore, the formation of an image in a color developed state and the erasure thereof can be reliably and promptly achieved.