Toner Crystalline Polyester Resin Low-Temperature Fixability
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Solution Overview
Problem
Crystalline polyester resins in toners exhibit slow crystallization rates, leading to incomplete crystal formation, which results in increased glass transition temperature and reduced low-temperature fixability when exposed to high temperature, high humidity environments over time, affecting the toner's stability and performance.
Innovation Solution
A toner formulation incorporating a polyester-type resin with a crystalline segment, where the terminal ends are condensed with long-chain aliphatic monocarboxylic acids or monoalcohols, promoting plasticization and stable low-temperature fixability, and utilizing temperature-modulated differential scanning calorimetry to control the endothermic peak percentage in the reversing heat flow to ensure thorough crystallization and maintain low-temperature fixability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a crystalline polyester resin is added to improve low-temperature fixability, then the low-temperature fixability is improved, but the glass transition temperature increases after long-term standing in high temperature and high humidity environments, causing deterioration of low-temperature fixability
Solution Approach 1:
The patent controls the endothermic peak percentage in the reversing heat flow within a specific range (5-50%) to optimize the crystalline segment content. This parameter control ensures sufficient crystallization for low-temperature fixability while preventing excessive crystallization that would cause Tg increase and performance deterioration over time.
Solution Approach 2:
The patent creates a composite resin system combining a polyester-type resin with a crystalline polyester resin. This composite structure allows the crystalline segments to provide low-temperature fixability enhancement while the overall composition maintains stability against environmental aging, resolving the contradiction between immediate performance improvement and long-term stability.
2Temperature
If the crystallization rate is increased to improve low-temperature fixability, then the low-temperature fixability is improved, but the risk of incomplete crystal formation and subsequent recrystallization increases, affecting temporal stability
Solution Approach 1:
The patent performs preliminary crystallization during the toner manufacturing process by controlling the cooling conditions and residence time, ensuring that the crystalline segments are adequately formed before the toner is put into service. This preliminary action prevents incomplete crystal formation that would later recrystallize and cause performance deterioration.
Solution Approach 2:
The patent optimizes the endothermic peak percentage parameter to balance crystallization completeness with temporal stability. By maintaining this parameter within the specified range, the patent ensures sufficient crystallization for low-temperature fixability while preventing conditions that would lead to recrystallization and performance degradation over time.
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 solution provides a toner with excellent and stable low-temperature fixability even after long-term exposure to high temperature, high humidity conditions, ensuring consistent image quality and durability by suppressing the increase in glass transition temperature and enhancing the crystallization rate.
Implementation Method 1
crystalline polyester resin... slow crystallization rate... component that does not completely convert into the crystal... crystalline polyester resin may recrystallize
Implementation Method 2
occurrence of micro non-uniformity in melting during toner melting... endothermic peak temperatures
Data Source
AI summary
The toner includes a resin component containing a crystalline polyester resin and a polyester-type resin that has a long-chain monomer bonded by condensation at a terminal, the toner having, in a total heat flow measured by a temperature-modulated differential scanning calorimeter, an endothermic peak resulting from the crystalline polyester resin in a specific temperature range, and the percentage of the endothermic quantity of the endothermic peak in a reversing heat flow with respect to the endothermic quantity of the endothermic peak in the total heat flow being at least 20.0%.