Toner Particle Lamellar Core Structure for Fixing
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Solution Overview
Problem
Current toners for electrostatic charge image development face challenges in achieving both low temperature fixability and heat-resistant storage properties while maintaining excellent chargeability, fixing separation property, and flowability.
Innovation Solution
A toner comprising binder resin with a crystalline polyester resin having a lamellar structure, where the lamellar structure is present only on the inside of the toner particle, as observed by ruthenium staining and transmission electron microscopy, with a content of 80% or more of the total toner particles, and a ratio of cross-sectional area of the lamellar structure to the toner particle of 1 to 20%, enhancing fusion, chargeability, and flowability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a crystalline polyester resin is used in toner to achieve low temperature fixability, then fixing temperature is reduced, but storage stability deteriorates
Solution Approach 1:
The patent applies local quality by creating a core-shell structure where the crystalline polyester resin is localized specifically in the core region (depth of 0.1 times particle diameter from surface to center), while the surface region (0 to 0.1 times particle diameter from surface) contains different materials that provide storage stability. This spatial differentiation allows the toner to simultaneously achieve low temperature fixability through the crystalline polyester in the core and heat-resistant storage properties through the surface composition.
2Temperature
If crystalline polyester resin is distributed throughout the toner particle, then low temperature fixability is improved, but chargeability and flowability deteriorate
Solution Approach 1:
The patent implements local quality by restricting the crystalline polyester resin to the core region only, preventing its presence in the surface region. This spatial separation ensures that the core provides low temperature fixability while the surface maintains good chargeability and flowability characteristics, as the surface composition is optimized for electrostatic properties and particle movement.
Solution Approach 2:
The patent applies segmentation by dividing the toner particle into distinct functional regions: a core region containing the crystalline polyester resin for low temperature fixability, and a surface region with different composition for chargeability and flowability. This segmentation allows each region to perform its specific function without interfering with the others.
3Temperature
If lamellar structure is present on the surface of toner particle, then low temperature fixability is enhanced, but fixing separation property deteriorates
Solution Approach 1:
The patent applies local quality by positioning the lamellar structure of the crystalline polyester resin exclusively in the core region (depth of 0.1 times particle diameter from surface to center), while ensuring the surface region (0 to 0.1 times particle diameter from surface) does not contain the lamellar structure. This spatial differentiation allows the core to provide low temperature fixability through the lamellar structure while the surface maintains good fixing separation properties.
Data Source
Figure 1~2
AI summary
Provided is a toner for electrostatic charge image development which satisfies both low temperature fixability and an excellent storage stability and realizes excellent chargeability, fixing separation property, and flowability. According to the present invention, there is provided a toner for electrostatic charge image development comprising toner particles which comprises a binder resin including a crystalline polyester resin and a release agent, in which the crystalline polyester resin has a lamellar structure and the lamellar structure is present only on the inside of the toner particle when a cross-section of the toner particle subjected to ruthenium staining is observed with a transmission electron microscope.