Core-Shell Toner with Partial Shell Coverage
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Solution Overview
Problem
Toner for developing electrostatic charge images faces challenges with poor thermal resistance during storage, inadequate charging properties, and inefficient release agent elution during high-speed printing, due to compatibility issues between core and shell layers and incomplete coating of external additives.
Innovation Solution
A toner with a core-shell structure where the core particle is coated with a shell layer at a specific coverage of 60 to 99%, using amorphous resins different from the core, and containing discrete shell domains, enhancing thermal resistance, durability, and releasability by efficient release agent elution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the core particle is completely coated with the shell layer, then thermal resistance during storage is improved, but releasability during fixation deteriorates due to inefficient release agent elution
Solution Approach 1:
The shell layer is applied at a specific coverage of 60 to 99% rather than complete coating. This partial coverage allows certain portions of the core particle surface to remain exposed, creating channels or pathways that facilitate efficient elution of the release agent during fixation, while still providing sufficient thermal resistance protection during storage.
2Temperature
If the core particle and shell layer are composed of different resins, then low-temperature fixing properties are improved, but compatibility between core and shell deteriorates resulting in discrete shell segments and rough surface
Solution Approach 1:
The invention introduces a specific parameter range for shell layer coverage (60-99%) and controls the resin composition to achieve optimal balance. By carefully selecting the type and amount of resin in the shell layer that is different from the core particle resin, the invention maintains low-temperature fixing properties while improving compatibility to reduce discrete shell segments.
3Reliability
If the shell layer coverage is increased to improve thermal resistance, then durability is improved, but manufacturing precision of coating uniformity deteriorates
Solution Approach 1:
The invention specifies a precise parameter range for shell layer coverage of 60 to 99%, which optimizes both durability and coating uniformity. This parameter control ensures that the shell layer provides sufficient protective coverage without creating excessive roughness or non-uniformity that would compromise manufacturing precision.
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 superior charging properties, high durability, and consistent gloss with improved thermal resistance and releasability, ensuring effective low-temperature fixing and high-speed printing performance.
Implementation Method 1
exhibiting high compatibility between low-temperature fixing properties and thermal resistance during storage
Implementation Method 2
the core particle includes an amorphous resin, a colorant, a release agent, and a crystalline resin; and the shell layer includes an amorphous resin
Implementation Method 3
exhibiting improved releasability by efficient elution of a release agent from the toner during fixation for high-speed printing
Data Source
Figure 1~2
Figure 3
AI summary
An electrostatic charge image developing toner includes a toner matrix particle having a core-shell structure. The toner matrix particle contains: a core particle including an amorphous resin, a colorant, a release agent, and a crystalline resin; and a shell layer coating a surface of the core particle at a coverage of 60 to 99%. The shell layer includes an amorphous resin. The amorphous resin contained in the core particle differs from the amorphous resin contained in the shell layer. The toner matrix particle has one to seven discrete shell domains determined by observation of a cross section of the toner matrix particle with an electron microscope.