Decolorizable Electrophotographic Toner for Common Paper

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Solution Overview

Problem

Current techniques for decolorizing images on paper are inefficient, particularly for common paper, as they involve complex structures, low color-changing temperatures, and insufficient reaction rates, leading to increased paper consumption and environmental concerns.

Innovation Solution

A decolorizable electrophotographic toner is developed, comprising a binder resin, an electron-donating color-developable agent, and waxes with specific acid values and melting points, which allows for image decolorization through a controlled heating process, enhancing heat-resistant storage stability and low-temperature fixability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If thermal color-developable compositions are encapsulated in separate microcapsules for decolorization, then decolorization capability is achieved, but the structure becomes complicated and it is limited to special paper only

Engineering Contradiction:
Improvedecolorization capabilityVSAvoidstructure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines multiple functional components (color-developable agent, color-developing agent, and decolorizing agent) into a single integrated toner particle structure, eliminating the need for separate microcapsules. This merging approach maintains decolorization capability while significantly simplifying the overall structure and enabling application on common paper.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The toner particle is designed to perform multiple functions simultaneously: image formation through electrophotography, color development through thermal reaction, and decolorization through heating. This multi-functionality eliminates the need for specialized paper and complex encapsulation structures, making the system universally applicable.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Ease of manufacture

If four essential components are encapsulated in microcapsules for color change, then color-changing function is achieved, but the structure becomes complicated and color-changing temperature becomes low

Engineering Contradiction:
Improvecolor-changing functionVSAvoidcolor-changing temperature
Core Design Contradiction:
Ease of manufactureVSTemperature

Solution Approach 1:

The patent carefully selects and adjusts the melting points of wax components and reaction temperatures to achieve optimal color development at appropriate temperatures. By controlling these parameters, the system achieves effective color changing without requiring excessively low temperatures or complex encapsulation.

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If all ingredients are mixed and kneaded in solid phase for decolorizable toner production, then production is simplified, but color developing and decolorizing reactions are not prompt or sufficient

Engineering Contradiction:
Improveproduction simplicityVSAvoidreaction efficiency
Core Design Contradiction:
Ease of manufactureVSProductivity

Solution Approach 1:

The patent utilizes phase transitions of wax components during the kneading process. By controlling the melting and solidification cycles of waxes with specific melting points, the system ensures thorough mixing of ingredients while maintaining reaction efficiency. The phase transitions enable prompt color developing and decolorizing reactions without requiring overly complex production processes.

Inventive Principle:
Principle #36Phase transitions

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 toner effectively decolorizes images on paper with improved heat-resistant storage stability and low-temperature fixability, reducing paper consumption and environmental impact while maintaining image density and decolorization efficiency.

Implementation Method 1

a color-developing reaction between a color-developable agent and a wax having a specific acid value

Methodology Applied
Scientific EffectColor-developing reaction: Chemical Bonding

Implementation Method 2

allows for image decolorization through a controlled heating process

Methodology Applied
Scientific EffectHeating: Heating

Data Source

PatentEP2256556B1Electrophotographic toner and process for producing electrophotographic toner
Publication Date: 2017.06.21 TOSHIBA TEC KK
  • EP2256556B1 patent drawingFigure 1
  • EP2256556B1 patent drawingFigure 2

AI summary

Disclosed is an decolorizable electrophotographic toner, containing a binder resin, an electron-donating color-developable agent, and a wax having a color-developing action and having an acid value of 60 mgKOH/g or more.