Toner Formulation for Low-Temperature Fixing and Hot Offset Resistance
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Solution Overview
Problem
Current toners face challenges in achieving both low-temperature fixability and thermostable preservability while maintaining hot offset resistance, leading to issues such as hot offset problems and poor image quality in electrophotographic image forming methods.
Innovation Solution
A toner formulation is developed that includes a combination of crystalline and amorphous resins, with specific glass transition temperature and endothermic quantity relationships, ensuring compatibility and optimal melting characteristics to achieve low-temperature fixability and thermostable preservability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a toner includes a resin or wax having a low softening point to enable low-temperature fixing, then low-temperature fixability is improved, but the toner becomes liable to hardening (blocking) with other heats and has poor thermostable preservability
Solution Approach 1:
The patent applies parameter changes by precisely controlling the glass transition temperature (Tg) within -50°C to 0°C and the melting point (Tm) within 70°C to 110°C, with specific relationship Tm - Tg between 60°C to 100°C. This quantitative parameter optimization enables low-temperature fixing while preventing hardening and maintaining thermostable preservability
Solution Approach 2:
The patent uses composite materials by combining specific binder resins (crystalline polyester resin, amorphous polyester resin, and/or polyurethane resin) with controlled molecular weights and glass transition temperatures. This composite resin system achieves both low-temperature fixability and resistance to hardening under various heat conditions
2Temperature
If the glass transition temperature of the toner is lowered to improve low-temperature fixability, then fixability at low temperature is improved, but thermostable preservability deteriorates
Solution Approach 1:
The patent applies parameter changes by establishing specific relationships between glass transition temperature (Tg: -50°C to 0°C) and melting point (Tm: 70°C to 110°C), with the difference Tm - Tg controlled between 60°C to 100°C. This dual-parameter control enables simultaneous achievement of low-temperature fixability and thermostable preservability
3Temperature
If the molecular weight of the resin is decreased to lower the softening point for low-temperature fixing, then low-temperature fixability is improved, but hot offset occurs at lower temperatures
Solution Approach 1:
The patent applies parameter changes by optimizing molecular weight parameters (weight-average molecular weight Mw: 5,000 to 50,000; number-average molecular weight Mn: 2,000 to 20,000) and controlling the Mw/Mn ratio between 2.5 to 5.0. This molecular weight optimization lowers the softening point for low-temperature fixing while preventing hot offset through appropriate molecular weight distribution
Solution Approach 2:
The patent uses composite materials by combining multiple resin types (crystalline polyester resin with specific Tm, amorphous polyester resin with specific Tg, and/or polyurethane resin) with controlled molecular weights. This composite resin system achieves both low softening point and high hot offset resistance
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 improved hot offset resistance, low-temperature fixability, and thermostable preservability, producing high-quality images under low-temperature fixing conditions.
Implementation Method 1
T1 represents a glass transition temperature of the toner before melting when heated from -20°C to 150°C at a heating speed of 10°C./min, and T2 represents a glass transition temperature thereof after melting
Implementation Method 2
Q1 represents an endothermic quantity at a melting point of the toner before melting when heated from -20°C to 150°C at a heating speed of 10°C./min
Implementation Method 3
T1 represents a glass transition temperature of the toner before melting when heated from -20°C to 150°C at a heating speed of 10°C./min, and T2 represents a glass transition temperature thereof after melting
Data Source
AI summary
A toner satisfying at least one of the following relationships: 10° C.<(T1−T2)<60° C. and 0<Q2/Q1<2/3 wherein T1 represents a glass transition temperature of the toner and Q1 represents an endothermic quantity at a melting point thereof before melting when heated from −20° C. to 150° C. at a heating speed of 10° C./min, and T2 represents a glass transition temperature thereof and Q2 represents a an endothermic quantity at a melting point thereof after melting after heated from −20° C. to 150° C. at a heating speed of 10° C./min, cooled to −20° C. at a cooling speed of 10° C./min and heated again at a heating speed of 10° C./min.