Electrophotographic Toner with Crystalline-Amorphous Polyester Domains
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Solution Overview
Problem
Conventional electrophotographic toner preparation methods face limitations in controlling toner structure and energy efficiency, with issues in cohesiveness, storage ability, and heat storage stability due to the exposure of releasing agents and pigment on the toner surface, and existing methods for improving low-temperature fixing characteristics do not adequately address heat storage stability.
Innovation Solution
An electrophotographic toner comprising a binder with crystalline and amorphous polyester resins, a colorant, and a releasing agent, where the morphological structure is optimized through specific domain ratios and acid value differences, and the toner is prepared using a method involving agglomeration and coating processes to achieve desired particle size and distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a releasing agent such as wax or pigment is exposed on the toner surface to improve low-temperature fixing characteristics, then low-temperature fixing ability is improved, but cohesiveness and storage ability of the toner are degraded
Solution Approach 1:
The patent applies local quality by creating distinct domains within the toner particle: a releasing agent domain (30-70 wt% of binder resin) that provides low-temperature fixing characteristics, and a crystalline polyester resin domain (70-65 wt% of binder resin) that maintains cohesiveness and storage ability. Each domain has specialized functions, with the releasing agent localized in specific regions rather than uniformly distributed on the surface.
Solution Approach 2:
The patent uses composite materials by combining crystalline polyester resin and amorphous polyester resin in a specific ratio (crystalline: 30-70 wt%, amorphous: 70-65 wt%) to create a binder system that simultaneously achieves low-temperature fixing (through crystalline resin) and maintains storage stability (through amorphous resin matrix).
2Temperature
If the amount of releasing agent is increased to improve low-temperature fixing characteristics, then fixing temperature is reduced, but heat storage stability is degraded due to plasticization
Solution Approach 1:
The patent applies parameter changes by precisely controlling the weight ratio of crystalline polyester resin to amorphous polyester resin (30-70:70-65) and the glass transition temperature difference (20-50°C). This quantitative parameter optimization allows the releasing agent to be present in sufficient amounts for low-temperature fixing while the crystalline resin structure prevents excessive plasticization and maintains heat storage stability.
Solution Approach 2:
The composite binder system combines crystalline polyester resin (providing structural stability and preventing plasticization) with amorphous polyester resin (providing flexibility and low-temperature fixing support), creating a balanced formulation that achieves both low-temperature fixing and heat storage stability.
3Manufacturing precision
If polymerized toner is used instead of pulverized toner to improve particle size control and resolution, then manufacturing complexity is reduced, but energy consumption increases during polymerization
Solution Approach 1:
The patent applies preliminary action by pre-synthesizing polyester resin particles with controlled size and morphology before forming the final toner particles. This preliminary particle preparation allows for better size control in the subsequent toner formation process, reducing the need for energy-intensive size reduction steps.
Solution Approach 2:
The patent replaces mechanical pulverization with chemical polymerization and particle formation processes. Instead of mechanically grinding materials to achieve desired particle sizes (which consumes huge energy), the invention uses controlled polymerization and phase separation to directly form particles of the desired size and morphology.
4Temperature
If encapsulation methods are used to improve low-temperature fixing characteristics by building core-shell structure, then fixing temperature is reduced, but charge variation between different colors increases
Solution Approach 1:
The patent applies local quality by creating specific domain structures within the toner particle where releasing agent domains (30-70 wt% of binder resin) and crystalline polyester resin domains (70-65 wt% of binder resin) are spatially separated and localized. This localized arrangement maintains consistent charge properties across different color toners while providing low-temperature fixing capability.
Data Source
AI summary
An electrophotographic toner including a binder, a colorant and a releasing agent, and a method of preparing the electrophotographic toner.