Core-Shell Toner with Purine Antiplasticizer for Blocking Prevention
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Solution Overview
Problem
Toner blocking phenomenon occurs during the pulverization process, leading to low image quality and poor storage stability due to wax embedding on toner surfaces, which results in high temperature softening and coagulation of toner particles, causing them to stick together and reducing flowability.
Innovation Solution
A core-shell toner composition is developed with a core containing a first styrene-acrylate resin and a shell with a second styrene-acrylate resin, both incorporating a purine derivative antiplasticizer, such as caffeine, to control the circularity of toner particles and prevent blocking, while maintaining fusing properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If a high percentage amount of polyester is replaced with styrene/acrylate, then the circularity of toner particles is reduced, but the surface morphology becomes very rough and toner blocking is not prevented
Solution Approach 1:
The invention applies different functional requirements to different parts of the toner particle: the core region allows for styrene/acrylate resin to reduce circularity and prevent blocking, while the surface region is treated to maintain smooth morphology through controlled coalescence conditions and pH adjustment, creating local quality differentiation within the particle structure
Solution Approach 2:
The invention changes multiple parameters simultaneously: resin composition (core-shell structure with different resins in core and shell), coalescence temperature (lowered to 65-80°C), and pH (adjusted to 3.5-6.0) to achieve the dual goal of reduced circularity and maintained surface smoothness, demonstrating parameter changes rather than relying on a single parameter adjustment
2Shape
If coalescence temperature is lowered or coalescing pH is increased, then the circularity of toner particles is reduced, but the surface morphology deteriorates from semi-smooth to very rough
Solution Approach 1:
The invention simultaneously optimizes multiple parameters (temperature, pH, and resin composition) rather than relying on single parameter adjustment. The specific combination of lowered coalescence temperature (65-80°C) with controlled pH (3.5-6.0) and core-shell resin structure creates a synergistic effect that achieves both reduced circularity and maintained surface smoothness
Solution Approach 2:
The invention uses a composite core-shell resin structure where the core contains styrene/acrylate resin for blocking prevention and the shell provides smooth surface morphology, combining materials with complementary properties to resolve the contradiction between circularity reduction and surface quality maintenance
3Ease of operation
If toner particles are made with high circularity, then flowability is improved, but toner blocking occurs at high temperature causing particles to stick together
Solution Approach 1:
The invention changes the circularity parameter from high (>0.98) to controlled lower values (0.940-0.980) to prevent blocking while maintaining adequate flowability. This parameter change is achieved through controlled coalescence conditions and resin composition rather than simple mechanical mixing
Solution Approach 2:
The invention creates a balance or equipotential state between two opposing requirements: flowability (which prefers high circularity) and blocking prevention (which prefers lower circularity). By optimizing to a specific circularity range rather than maximizing it, the invention achieves a balanced state where both flowability and storage stability are satisfied
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 use of purine derivative antiplasticizers in the core and/or shell of toner particles reduces circularity to less than 0.980, preventing toner blocking, improving transfer efficiency, developability, and flowability, and maintaining a smooth surface for better print quality.
Implementation Method 1
toner particles having a core and a shell disposed over the core, wherein the core comprises an optional first antiplasticizer; a first styrene-acrylate resin; and the shell comprises an optional second antiplasticizer; and a second styrene-acrylate resin; wherein the toner particles include at least one of the first antiplasticizer or the second antiplasticizer and further wherein at least one of the first antiplasticizer or the second antiplasticizer comprises a purine derivative
Implementation Method 2
coalescing the particles at a temperature from about 65°C to about 80°C, and pH from about 3.5 to about 6.0
Implementation Method 3
Blocking is a phenomena where toner is subject to a high temperature softens on its surface and toner particles coagulate or stick together
Implementation Method 4
aggregating the emulsion to form particle cores
Data Source
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AI summary
Disclosed herein include styrene-acrylic-based compositions containing a purine derivative antiplasticizer with particles having a core-shell type structure and methods for their preparation.