Electrophotographic Toner with Polyester Binder for Decolorization
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Solution Overview
Problem
Conventional decolorizable toners have insufficient decolorization performance, with noticeable gloss in decolorized regions and poor low-temperature fixability, making them unsuitable for reuse in printing or note-taking applications.
Innovation Solution
An electrophotographic toner composition comprising an electron donating color former compound, an electron accepting color developing agent, and a polyester binder resin with specific molecular weight and glass transition point ranges, microencapsulated with a temperature control agent, to achieve effective decolorization and low-temperature fixability without noticeable gloss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional decolorizable toner is used, then decolorization function is provided, but decolorization performance is insufficient and gloss is noticeable in decolorized regions
Solution Approach 1:
The patent changes the molecular weight parameter of the binder resin to a specific range (5,000-20,000) and the glass transition point to a specific range (40-70°C) to optimize both decolorization performance and reduce gloss. This parameter optimization allows the toner to achieve complete decolorization while maintaining low gloss in decolorized regions.
Solution Approach 2:
The patent uses a composite binder resin system comprising polyester resin and polyurethane resin in specific proportions (polyester: 70-90 mass%, polyurethane: 10-30 mass%). This composite material approach combines the advantages of both resins to achieve the desired decolorization performance and gloss reduction simultaneously.
2Ease of operation
If conventional decolorizable toner is used, then image formation is enabled, but low-temperature fixability is poor
Solution Approach 1:
The patent optimizes the glass transition point of the binder resin to a specific range (40-70°C) to enable low-temperature fixing. By controlling the molecular weight and composition of the binder resin, the toner achieves good fixability at lower temperatures while maintaining image formation quality.
Solution Approach 2:
The patent applies different resin components with specific properties to different functional requirements: polyester resin provides structural integrity and fixability, while polyurethane resin enhances low-temperature performance. This local quality differentiation within the binder system resolves the temperature contradiction.
3Device complexity
If binder resin with inappropriate molecular weight is used, then toner formulation is simplified, but gloss becomes noticeable in decolorized regions
Solution Approach 1:
The patent specifies the molecular weight of the binder resin within a precise range (5,000-20,000) to control the gloss in decolorized regions. This parameter control ensures that the toner particles maintain appropriate morphology and decolorization characteristics without requiring complex multi-component binder systems.
Solution Approach 2:
The patent differentiates the molecular weight requirements for different resin components: polyester resin with molecular weight 5,000-20,000 and polyurethane resin with molecular weight 3,000-15,000. This local quality specification for each component achieves gloss reduction while maintaining formulation manageability.
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 achieves efficient decolorization with reduced gloss in the decolorized region, enabling effective reuse of printed sheets while maintaining low-temperature fixability and energy efficiency.
Implementation Method 1
a temperature control agent, and the toner is decolorized by heating
Implementation Method 2
a heat-sensitive recording medium (heat-sensitive paper) capable of erasing printing by heating, or a pigment or the like, which is decolorized by heating
Data Source
AI summary
An electrophotographic toner, which is decolorized by heating and a glossiness after decolorization of which is less than 10, comprising an electron donating color former compound, an electron accepting color developing agent, and a polyester binder resin.