Decolorable Electrophotographic Toner via Controlled Aggregation
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Solution Overview
Problem
The kneading pulverization method for producing electrophotographic toner has limitations in reducing toner particle diameter, leading to incomplete image erasure due to residual acidic metal salts and pH adjusting agents, which also affect environmental variability and image clarity.
Innovation Solution
A method involving aggregation and fusion of color former and binder resin in a dispersion medium with controlled pH between 5.5 to 9 and using acidic metal salts as aggregating agents, with a content of 1% or less, to inhibit binding and surfactant retention, ensuring effective image erasure and environmental stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the kneading pulverization method is used to produce toner, then the toner can be manufactured with standard particle size, but the particle diameter cannot be reduced sufficiently for high-quality images
Solution Approach 1:
The patent changes the production method from mechanical kneading pulverization to a wet chemical process using acidic metal salts in a dispersion medium. This parameter change enables precise control of particle diameter through chemical reactions rather than mechanical force, achieving the fine particle sizes needed for high-quality images while maintaining manufacturing efficiency
2Ease of manufacture
If acidic metal salts and pH adjusting agents are used in the kneading pulverization method, then the aggregation process can be facilitated, but residual amounts cause incomplete image erasure and environmental variability
Solution Approach 1:
The patent extracts and eliminates the harmful residual acidic metal salts and pH adjusting agents from the toner particles through careful control of the wet chemical process. By optimizing the dispersion medium composition and reaction conditions, the method achieves complete aggregation while removing excess chemicals, ensuring reliable image erasure and environmental stability
Solution Approach 2:
The patent changes the chemical parameters of the dispersion medium and controls the concentration and type of acidic metal salts used. This enables facilitation of the aggregation process while maintaining residual chemical levels below thresholds that would interfere with image erasure, thus resolving the contradiction between ease of manufacture and reliability
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 allows for sufficient image erasure and improved environmental variability by controlling the pH and content of acidic metal salts, reducing image density and maintaining toner stability.
Implementation Method 1
a step of aggregating and fusing a color former compound and a color developing agent, and a binder resin in a dispersion medium
Implementation Method 2
aggregation and fusion of color former and binder resin in a dispersion medium with controlled pH between 5.5 to 9
Data Source
AI summary
A decolorable electrophotographic toner, containing a color former compound, a color developing agent, a binder resin, and a release agent, wherein the toner has a pH of from 6 to 9 when dispersed in water with a pH of from 5.5 to 7 at a mass ratio of toner/water of 1/10.