Crystalline Polyester Toner Fixability
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Solution Overview
Problem
Toner formulations face challenges in achieving low-temperature fixability while maintaining heat-resistant storage stability and preventing filming on image forming apparatus components, as existing toners either lack sufficient filming resistance or exhibit poor fixability when trying to balance these properties.
Innovation Solution
A toner composition comprising a colorant, a release agent, an amorphous polyester, and a crystalline polyester with specific endothermic peak temperatures and quantities, optimized through temperature-modulated differential scanning calorimetry, along with resin particles on the toner surface to control fixability and hardness, is developed. The crystalline polyester is obtained from saturated aliphatic diols and dioic acids, and the amorphous polyester is urea-modified, allowing for improved low-temperature fixability and heat-resistant storage stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a toner comprises an amorphous polyester resin and a crystalline polyester resin with specific DSC characteristics (onset temperature 100-150°C, terminating point 150-200°C, half width 10-40°C), then low-temperature fixability is improved, but filming resistance deteriorates
Solution Approach 1:
The invention changes the thermal parameters of the crystalline polyester resin by selecting specific combinations of diols and dioic acids with controlled molar ratios. This results in a crystalline polyester with a melting point of 70-90°C and specific crystallinity (30-70%), which modifies the DSC curve characteristics to reduce filming while maintaining low-temperature fixability through precise parameter control of the resin components
Solution Approach 2:
The invention uses a composite binder resin system comprising both amorphous polyester resin and crystalline polyester resin in specific weight ratios (amorphous:crystalline = 95:5 to 50:50). This composite structure combines the low-temperature flow properties of amorphous resin with the thermal stability and filming resistance of crystalline resin, achieving both low-temperature fixability and reduced filming
2Object-generated harmful factors
If the crystalline polyester resin has an endothermic peak temperature of 60 to 80°C with specific endothermic quantity, then filming resistance is improved, but low-temperature fixability may deteriorate
Solution Approach 1:
The invention optimizes the endothermic characteristics of crystalline polyester by controlling the melting point (70-90°C) and crystallinity (30-70%) through specific monomer selections and molar ratios. The endothermic peak temperature is controlled at 70-90°C with an endothermic quantity of 5-20 J/g, which provides sufficient filming resistance while maintaining adequate low-temperature fixability through balanced parameter control
Solution Approach 2:
The invention creates local quality differences within the binder resin system by having the crystalline polyester resin provide filming resistance through its specific endothermic characteristics, while the amorphous polyester resin provides low-temperature flow and fixability. Each component has optimized local properties that complement the other, achieving overall performance balance
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 a balance of low-temperature fixability, heat-resistant storage stability, and reduced filming resistance, enabling efficient image formation with improved surface hardness and fixability, as demonstrated by specific thermal and imaging performance metrics.
Implementation Method 1
a crystalline polyester having an endothermic peak temperature of 60 to 80°C and an endothermic quantity of 5 to 15 J/g
Implementation Method 2
The endothermic peak temperature is determined from a constant rate component curve of the crystalline polyester obtained in a second heating of temperature-modulated differential scanning calorimetry
Data Source
Figure 1~2
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AI summary
A toner comprising a colorant, a release agent, an amorphous polyester, and a crystalline polyester having an endothermic peak temperature of 60 to 80°C and an endothermic quantity of 3.0 to 20.0 J/g. The endothermic peak temperature is determined from a constant rate component curve of the crystalline polyester obtained in a second heating of temperature-modulated differential scanning calorimetry. The endothermic quantity is determined from an area between the constant rate component curve and its base line drawn between 0 and 100°C, within a temperature range of 0 to 50°C.