Crystalline Polyester Toner for Low-Temperature Fixing
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Solution Overview
Problem
Existing toner technologies face challenges in achieving low-temperature fixability while maintaining storage stability and preventing powder aggregation, as lowering the glass transition temperature of binder resins can lead to blocking issues.
Innovation Solution
A toner formulation incorporating a crystalline polyester resin with a melting temperature of 50-100°C and a non-crystalline polyester resin, where the melting temperatures Tm1, Tm2, and Tm3 satisfy specific relationships to ensure compatibility and dispersion, thereby maintaining thermal storage stability and low-temperature fixability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the glass transition temperature of binder resin is lowered to achieve low-temperature fixability, then the fixing temperature can be reduced, but powder aggregation (blocking) occurs easily
Solution Approach 1:
The patent uses a composite binder resin system comprising both crystalline polyester resin and non-crystalline polyester resin. The crystalline resin provides low-temperature fixability through its melting point characteristics, while the non-crystalline resin maintains storage stability and prevents blocking. This composite approach allows the toner to be fixed at low temperatures without sacrificing storage reliability.
Solution Approach 2:
The patent carefully controls the glass transition temperature of the non-crystalline polyester resin within a specific range (40°C to 80°C) and the melting point of the crystalline polyester resin within another specific range (50°C to 100°C). By optimizing these temperature parameters, the toner achieves both low-temperature fixability and resistance to powder aggregation during storage.
2Adaptability or versatility
If the glass transition temperature of binder resin is lowered to expand the temperature range for fixation, then more temperature flexibility is achieved, but powder aggregation occurs easily
Solution Approach 1:
The dual-resin system enables the toner to adapt to a broader temperature range for fixation. The crystalline resin melts at 50-100°C providing fixation capability, while the non-crystalline resin with Tg of 40-80°C ensures the toner particles remain separate and do not aggregate during storage, even at lower temperatures.
Solution Approach 2:
By setting specific parameter ranges for both resins - crystalline resin melting point (50-100°C) and non-crystalline resin glass transition temperature (40-80°C) - the patent expands the usable temperature range for fixation while maintaining storage stability and preventing harmful powder aggregation.
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 both low-temperature fixability and storage stability by ensuring the crystalline polyester resin is dispersed in a non-compatible state, preventing conductive paths and maintaining charging properties, while allowing compatibility for low viscosity and effective fixation at temperatures up to 120°C or less.
Implementation Method 1
a crystalline polyester resin having a melting temperature Tm1 (° C.) of approximately 50 to approximately 100° C.
Implementation Method 2
the temperature Tm2 (° C.) of an endothermic peak derived from the crystalline polyester resin in a first process of raising temperature and the temperature Tm3 (° C.) of the endothermic peak derived from the crystalline polyester resin in a second process of raising temperature
Data Source
AI summary
The invention provides a toner for development of an electrostatic image, which has colored particles containing a crystalline polyester resin having a melting temperature Tm1 (° C.) of approximately 50 to approximately 100° C., a non-crystalline polyester resin, and a coloring agent, the temperature Tm2 (° C.) of an endothermic peak derived from the crystalline polyester resin in a first process of raising temperature and the temperature Tm3 (° C.) of an endothermic peak derived from the crystalline polyester resin in a second process of raising temperature, in differential scanning calorimetry based on JIS K7121:1987, satisfying the following relationships (1) and (2):0≦(Tm1−Tm2)<2 (1)4<(Tm1−Tm3)≦15 (2)