Core-Shell Toner Additive for Fixing and Durability
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Solution Overview
Problem
Existing toners face challenges in achieving high developing performance and image quality while maintaining durability and preventing discharged paper adhesion, particularly at high printing speeds, due to trade-offs between surface layer melting performance and durability, leading to issues like fixing non-uniformity and cartridge damage.
Innovation Solution
A toner comprising a binder resin and a colorant with an external additive in the form of a core-shell type composite particle, where the core contains an organic substance or crystalline polyester resin and is coated with an organosilicon polymer, optimizing the softening point and viscoelastic properties to enhance melting performance and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If silica-coated resin microparticles are used as external additive, then charging performance and fluidity are improved, but low temperature fixability is impaired
Solution Approach 1:
The external additive is segmented into core-shell type composite particles with distinct functional zones: the core contains organic substances for charging performance, while the shell contains low melting point substances for low-temperature fixing. This segmentation allows each part to independently contribute its specific function without interfering with the other.
Solution Approach 2:
Different regions of the external additive have different properties tailored to specific functions. The core region provides charging performance enhancement, while the shell region provides low-temperature melting capability. This local differentiation resolves the contradiction by providing both required properties in different locations of the same additive particle.
2Temperature
If crystalline polyester is added to increase sharp melting performance, then low temperature fixing performance is improved, but toner deformation and fixing non-uniformity occur
Solution Approach 1:
The low melting point substance is localized in the shell of the external additive particle, affecting only the surface region of the toner. This localized melting improves fixing performance without causing excessive deformation of the entire toner particle, thereby maintaining shape stability while achieving low-temperature fixing.
Solution Approach 2:
The external additive combines organic substances in the core with low melting point substances in the shell, creating a composite structure that balances melting performance with structural integrity. The composite nature allows the toner to melt sufficiently for fixing while maintaining enough rigidity to prevent excessive deformation.
3Shape
If crystalline polyester is present at the surface layer, then fixing non-uniformity is suppressed, but charging performance and fluidity are greatly impaired
Solution Approach 1:
The external additive is segmented into core-shell structure where the core contains organic substances for charging performance and the shell contains low melting point substances for fixing uniformity. This segmentation allows both functions to coexist without the trade-off present in conventional surface-only modifications.
Solution Approach 2:
The core-shell composite structure combines materials with complementary properties: the organic core maintains charging performance while the low-melting-point shell provides fixing uniformity. This composite approach overcomes the limitations of using单一 materials at the surface.
4Temperature
If inorganic fine particles are embedded in resin fine particle, then surface melting performance is improved, but cartridge durability is impaired due to protruding parts damaging developing sleeve and photosensitive drum
Solution Approach 1:
The shell containing the low melting point substance acts as a flexible, conformal coating that adapts to surface irregularities rather than creating hard protrusions. This flexible shell improves surface melting performance while preventing mechanical damage to cartridge components, thereby maintaining durability.
Solution Approach 2:
The core-shell composite particle combines organic core material with a low-melting-point shell material, creating a structure that provides surface melting performance without the mechanical damage issues associated with embedded inorganic particles. The composite structure is more compatible with cartridge components.
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 solution enables simultaneous improvement in toner durability, printing speed, and image quality, while reducing discharged paper adhesion and fixing non-uniformity, by selectively melting at the toner surface and maintaining elasticity, thus overcoming the trade-off between melting performance and durability.
Implementation Method 1
an organosilicon polymer coating layer on the surface of the core... selectively melting at the toner surface
Implementation Method 2
optimizing the softening point and viscoelastic properties to enhance melting performance and durability... maintaining elasticity
Data Source
AI summary
A toner comprising: a toner particle containing a binder resin and a colorant; and an external additive, wherein the external additive is a composite particle having an organic substance and an organosilicon polymer coating layer on the surface of the organic substance, and when a curve for the variation (dE′/dT) in the storage elastic modulus E′ of the toner with respect to temperature T [° C.] is obtained on the basis of a curve of the temperature T—the storage elastic modulus E′ [Pa] of the toner, as determined by powder dynamic viscoelasticity measurements of the toner, the relative minimum value on the lowest temperature side between the onset temperature and 90° C. is −1.35×108 or less.