Electrophotographic Toner Core Shell Structure Low Temperature Fixing
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Solution Overview
Problem
Electrophotographic toners with low softening and glass transition points facilitate low temperature fixing but are prone to toner-to-toner coagulation and tacking issues during storage and image handling.
Innovation Solution
Incorporating an ester compound and an aliphatic hydroxycarboxylic acid compound in the releasing agent of the toner, specifically formed from long chain alkyl or alkenyl alcohols, to enhance the surface hardness of fixed images and prevent tacking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a binder resin with low softening point and low glass transition point is used to achieve low temperature fixing, then fixing temperature is reduced, but toner-to-toner coagulation occurs during storage
Solution Approach 1:
The invention applies local quality by creating a core/shell structure where the core contains the low glass transition point binder resin for low temperature fixing, while the shell contains a high glass transition point resin to prevent coagulation during storage. This spatial differentiation allows each region to perform its specific function without interfering with the other.
Solution Approach 2:
The invention uses composite materials by combining binder resins with different glass transition points in a core/shell configuration. The core uses a binder resin with low glass transition point (e.g., polyester resin with Tg of 60-80°C) for low temperature fixing, while the shell uses a resin with high glass transition point (e.g., styrene-acrylic copolymer with Tg of 80-100°C) to maintain storage stability and prevent coagulation.
2Temperature
If a binder resin with low glass transition point is used to achieve low temperature fixing, then fixing temperature is reduced, but tacking occurs between fixed images
Solution Approach 1:
The shell layer with high glass transition point resin provides local quality enhancement at the toner surface, creating a harder outer layer that prevents tacking between fixed images while the core maintains low temperature fixing capability through its low glass transition point binder resin.
Solution Approach 2:
The composite core/shell structure combines materials with different thermal properties: the core binder resin (low Tg) enables low temperature fixing, while the shell resin (high Tg) provides resistance to tacking by maintaining structural integrity at room temperature after fixing.
3Stability of the object's composition
If a shell layer with high glass transition point resin is added to prevent coagulation, then storage stability is improved, but device complexity increases
Solution Approach 1:
The shell layer is applied as a thin surface coating rather than a thick structural layer, providing the necessary high glass transition point properties to prevent coagulation while minimizing the addition of material and structural complexity. The shell serves as a functional surface layer rather than a bulk structural component.
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
Achieves low temperature fixing while maintaining high storage stability and preventing tacking between images, thereby improving detachability and storage performance.
Implementation Method 1
the releasing agent contains at least an ester compound and an aliphatic hydroxycarboxylic acid compound
Data Source
AI summary
In the present invention, provided is an electrophotographic toner in which low temperature fixing is achieved, and high storage stability is obtained without generating tacking with respect to fixed images to be formed. It is a feature that this electrophotographic toner possesses at least a binder resin, a colorant and a releasing agent, wherein the releasing agent comprises an ester compound and an aliphatic hydroxycarboxylic acid compound.