Toner Binder Resin Blend for Low-Temperature Fixing
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Solution Overview
Problem
Current toners for ultra high-speed printing systems face challenges in achieving both low-temperature fixing property, anti-offset property, and heat-resistance storage stability while maintaining high productivity and reducing the friction coefficient of fixed images, which is essential for advanced electrophotographic printing technologies like print on demand (POD).
Innovation Solution
A toner composition comprising a binder resin blend of polyester resins (A), (B), and (C), where (A) and (B) are prepared with 1,2-propanediol and a carboxylic acid component, and (C) is an alkylene oxide adduct of a bisphenol compound, optimized to achieve a specific softening point ratio and acid value range, enhancing low-temperature fixing, anti-offset, and heat-resistance storage stability, and reducing the friction coefficient of fixed images.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a low-molecular weight polyester prepared using an aliphatic alcohol is used to improve pulverizability, then productivity is improved, but heat resistance-storage stability is degraded due to low glass transition temperature
Solution Approach 1:
The patent changes the chemical composition parameters of the polyester resin by incorporating specific proportions of 1,2-propanediol (65-95 mol%) and 1,3-propanediol (5-35 mol%) in the alcohol component, and adjusting the carboxylic acid component ratios, to achieve optimal balance between glass transition temperature and melting point. This parameter optimization enables both good pulverizability and heat resistance-storage stability
Solution Approach 2:
The patent creates a composite polyester resin system combining multiple alcohol components (1,2-propanediol and 1,3-propanediol) and multiple carboxylic acid components (adipic acid, succinic acid, and itaconic acid) in specific ratios. This composite approach allows the resin to simultaneously achieve low enough glass transition temperature for pulverizability and appropriate melting point for heat resistance
2Use of energy by moving object
If a toner is designed for low-temperature fixing to reduce energy consumption, then energy saving is improved, but anti-offset property and heat resistance-storage stability are degraded
Solution Approach 1:
The patent optimizes the resin composition parameters to achieve a specific glass transition temperature range (40-70°C) and melting point range (80-120°C), allowing low-temperature fixing while maintaining adequate heat resistance through careful selection of 1,2-propanediol and carboxylic acid component proportions
Solution Approach 2:
The patent introduces functional differentiation within the resin structure by assigning 1,2-propanediol primarily to control glass transition temperature for low-temperature fixing, while 1,3-propanediol and carboxylic acid components work together to maintain melting point and crystallinity for anti-offset property and heat resistance-storage stability
3Productivity
If printing speed is increased for ultra high-speed printing systems, then productivity is improved, but the friction coefficient of fixed images increases causing poor print quality
Solution Approach 1:
The patent adjusts the resin composition parameters to achieve specific friction coefficient ranges by optimizing the balance between 1,2-propanediol content (affecting surface properties) and carboxylic acid component content (affecting molecular structure), thereby reducing image friction even at ultra high-speed printing
4Productivity
If conventional polyester resins are used to achieve good pulverizability, then productivity is improved, but low-temperature fixing property is degraded due to high glass transition temperature
Solution Approach 1:
The patent fundamentally changes the alcohol component from conventional options to a specific formulation with 1,2-propanediol (65-95 mol%) and 1,3-propanediol (5-35 mol%), which achieves the critical balance of glass transition temperature (40-70°C) for low-temperature fixing while maintaining molecular structure suitable for pulverizability
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 excellent low-temperature fixing, anti-offset, and heat-resistance storage stability, significantly reducing the friction coefficient of fixed images, thereby improving print quality and productivity in ultra high-speed printing systems, particularly suitable for POD technology.
Implementation Method 1
the binder resin contains polyester resin (A), polyester resin (B), and polyester resin (C), which is prepared by condensation-polymerizing (i) an alcohol component containing an alkylene oxide adduct of a bisphenol compound
Implementation Method 2
a method in which a low-molecular weight polyester prepared using an aliphatic alcohol that is excellent in pulverizability as a monomer is blended with a highly polymeric polyester
Implementation Method 3
a toner having excellent low-temperature fixing property increases, and at the same time, there is increased needs for a toner having property opposing to low-temperature fixing property
Data Source
Figure 1~2
Figure 3
AI summary
A toner containing at least a binder resin, releasing agent, and colorant, wherein the binder resin contains polyester resin (A), polyester resin (B), and polyester resin (C), which is prepared by condensation-polymerizing (i) an alcohol component containing an alkylene oxide adduct of bisphenol compound and (ii) a carboxylic acid component; at least one of the polyester resin (A) and polyester resin (B) is a polyester resin prepared by condensation-polymerizing (i) the alcohol component substantially composed of only aliphatic alcohol and containing 1,2-propanediol in an amount of 65 mole% or more of a divalent alcohol component and (ii) the carboxylic acid component; and a softening point Tm(A) of the polyester resin (A) is 10 C or more higher than Tm(B) of the polyester resin (B), and the absolute difference between Tm(C) of the polyester resin (C) and the Tm(B) is 5°C or less.