Toner Composition with Crystalline Polyester for Offset Resistance
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Solution Overview
Problem
Current toners face challenges in achieving a good combination of low temperature fixability, hot offset resistance, and thermostable preservability, while also preventing carrier adherence in high-speed image forming processes, which affects the quality and durability of images produced.
Innovation Solution
A toner composition comprising amorphous polyesters with specific softening points, a crystalline polyester, and a fatty acid amide compound, where the crystalline polyester's softening point is lower than the fatty acid amide's, ensuring compatibility and effective recrystallization, and a developer with a carrier having a controlled particle diameter distribution to prevent carrier adherence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the temperature of heat roller is decreased to prevent offset, then offset resistance improves, but toner cannot be sufficiently melted and fixed
Solution Approach 1:
The invention changes the chemical composition parameters of the binder resin by incorporating specific polyester resins with controlled softening points (70-140°C) and glass transition temperatures (30-80°C). This allows the toner to maintain structural integrity at storage temperatures while becoming sufficiently meltable at reduced fixing temperatures, thereby preventing offset without compromising fixability.
Solution Approach 2:
The invention uses a composite binder resin system combining multiple polyester resins with different thermal properties. The amorphous polyester provides low-temperature meltability while the crystalline polyester maintains thermostable preservability. This composite structure enables the toner to exhibit both low-temperature fixability and hot offset resistance simultaneously.
2Temperature
If amount of resin with lower softening point is increased to improve low temperature fixability, then fixability improves, but thermostable preservability and hot offset resistance deteriorate
Solution Approach 1:
The invention precisely controls the softening point parameter of the binder resin to be 70-140°C and glass transition temperature to be 30-80°C by selecting specific polyester resin compositions. This parameter optimization allows the toner to melt sufficiently at low fixing temperatures while maintaining compositional stability during storage, resolving the trade-off between fixability and preservability.
Solution Approach 2:
The invention applies different functional properties to different components of the binder resin system. The amorphous polyester component provides low-temperature meltability for fixability, while the crystalline polyester component provides thermal stability for preservability. Each component performs its specific function locally within the composite resin system.
3Manufacturing precision
If carrier particle diameter is decreased to improve image quality, then image quality improves, but carrier adherence increases
Solution Approach 1:
The invention optimizes the carrier particle diameter parameter to a specific range that balances image quality and carrier adherence prevention. By controlling the carrier size within defined limits and combining it with optimized toner composition, the system achieves high image quality without excessive carrier adherence even at high speeds.
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 improved low temperature fixability, hot offset resistance, and thermostable preservability, while preventing carrier adherence, resulting in high-quality, durable images even at high speeds.
Implementation Method 1
the crystalline polyester resin has a thermal property such that viscosity thereof rapidly decreases at a temperature at which the toner starts to be fixed, due to its crystallinity
Implementation Method 2
the crystalline polyester resin starts to rapidly decrease its viscosity at the melting point
Implementation Method 3
the fatty acid amide compound, which has a higher softening point than the crystalline polyester resin, is included in the domain of the crystalline polyester resin, and upon melting of the crystalline polyester resin, the fatty acid amide compound recrystallizes
Data Source
AI summary
A toner is provided including a binder resin; a release agent; a colorant; and a fatty acid amide compound, wherein the binder resin includes: an amorphous polyester (A) having a softening point of from 70 to 140° C.; an amorphous polyester (B) having a softening point of from 120 to 190° C.; and a crystalline polyester (C), and wherein the following relationship is satisfied: TmC<Tm(Asp), wherein TmC represents a softening point of the crystalline polyester (C) and Tm (Asp) represents a softening point of the fatty acid amide compound; and a developer and an image forming apparatus using the toner.