Toner Formulation for Low Temperature Fixing and Hot Offset Resistance
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Solution Overview
Problem
Conventional toners face challenges in maintaining low temperature fixing properties while ensuring stable charging ability and hot offset resistance, especially under high temperature and high humidity conditions, due to the trade-off between molecular weight and moisture absorption of binder resins.
Innovation Solution
A toner formulation incorporating a binder resin and a release agent, with specific soluble and insoluble components, including a crystalline polyester resin, to achieve a balanced low temperature fixing property, reduced charging variation, and improved storability, as determined by controlled molecular weight and solubility in a 50% aqueous methanol solution and flowing-out beginning temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the molecular weight of binder resin is decreased to achieve low temperature fixing, then the melting temperature is lowered, but the toner is prematurely softened before fixing resulting in poor image quality and failure in toner replenishment
Solution Approach 1:
The patent applies parameter changes by precisely controlling the molecular weight of the binder resin within a specific range (10,000 to 30,000) and adjusting the molecular weight distribution (Mw/Mn ratio between 2.0 and 10.0). This optimization allows the toner to maintain adequate melting temperature while achieving low-temperature fixing properties, preventing premature softening and ensuring good image quality.
Solution Approach 2:
The patent uses a composite binder resin system comprising multiple resin components with different molecular weights and properties. This composite approach allows the toner to exhibit both low-temperature melting characteristics and sufficient thermal stability during storage and handling, resolving the contradiction between low melting point and premature softening.
2Temperature
If the molecular weight of binder resin is decreased to achieve low temperature fixing, then the low molecular weight components increase, but the toner is greatly deteriorated in charging ability leading to unstable developing ability
Solution Approach 1:
The patent optimizes the molecular weight parameters of the binder resin, specifically setting Mn between 10,000 and 30,000 and Mw/Mn between 2.0 and 10.0. This controlled parameter range ensures that low molecular weight components are sufficient for low-temperature fixing but not excessive to cause charging ability deterioration.
Solution Approach 2:
The patent applies local quality by ensuring uniform distribution of resin components and low molecular weight substances throughout the toner particles. This prevents localized concentration of hydrophilic groups that would cause moisture absorption and charging ability deterioration, while maintaining overall low-temperature fixing performance.
3Reliability
If the acid value and hydroxyl value are decreased to prevent moisture absorption, then the low temperature fixing property is compromised, but decreasing them too much is inappropriate
Solution Approach 1:
The patent optimizes the acid value and hydroxyl value parameters within specific ranges, balancing moisture resistance and low-temperature fixing. By controlling these parameters along with molecular weight, the patent achieves both good storability under high temperature and humidity conditions and adequate low-temperature fixing performance.
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 exhibits reduced charging variation, enhanced low temperature fixing property, and improved hot offset resistance, maintaining performance in high temperature and high humidity environments.
Implementation Method 1
the toner is required to be melted at a lower temperature
Implementation Method 2
has a component soluble in a 50% by mass aqueous methanol solution in an amount of 0.10% by mass to 0.60% by mass
Data Source
AI summary
A toner including a binder resin and a release agent, wherein the toner has a component soluble in a 50% by mass aqueous methanol solution in an amount of 0.10% by mass to 0.60% by mass, and wherein the toner has a flowing-out beginning temperature (Tfb) of 55.0° C. to 100.0° C. as determined by a flowtester method.