Toner Composition for Low-Temperature Fixing and High Gloss
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Solution Overview
Problem
Existing toners for electrostatic image development face challenges in achieving a wide fusing latitude, high gloss, anti-cohesiveness, storage stability, and low-temperature fixing ability, particularly due to issues with binder resin transparency, fixing temperature, and heat storage ability.
Innovation Solution
A toner composition including a binder resin, a coloring agent, and a releasing agent, where the particle morphology is optimized with specific solubility parameter differences and domain distribution, and a low molecular weight binder resin is used to enhance fusing latitude, gloss, and storage stability, while maintaining low-temperature fixing ability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If much wax which is a releasing agent is contained to achieve low-temperature fixing ability, then fixing temperature is reduced, but heat storage ability and anti-cohesiveness deteriorate due to plasticization
Solution Approach 1:
The patent modifies the molecular weight parameter of the binder resin, specifically using a resin with Tg of 80-120°C and weight-average molecular weight of 50,000-150,000. This parameter change allows the binder to maintain appropriate viscosity and plasticization behavior at lower fixing temperatures while preserving heat storage ability and anti-cohesiveness.
Solution Approach 2:
The patent creates a composite toner system combining specific binder resin (polyester resin with controlled Tg and molecular weight), releasing agent (wax), and coloring agent. This composite formulation achieves synergistic effects where the binder resin provides structural integrity and heat storage while the wax provides low-temperature releasing properties.
2Temperature
If much wax which is a releasing agent is contained to achieve low-temperature fixing ability, then fixing temperature is reduced, but anti-cohesiveness deteriorates due to plasticization
Solution Approach 1:
The patent optimizes the molecular weight parameter of the binder resin to 50,000-150,000 with Tg of 80-120°C. This specific parameter range controls the degree of plasticization, allowing the toner to maintain anti-cohesiveness while achieving low-temperature fixing through wax addition.
3Temperature
If methods are used to reduce glass transition temperature (Tg) of the binder resin to achieve low-temperature fixing, then fixing temperature is reduced, but heat storage ability and high gloss are insufficient
Solution Approach 1:
Instead of reducing Tg, the patent increases the Tg of the binder resin to 80-120°C and controls the molecular weight at 50,000-150,000. This parameter inversion approach allows low-temperature fixing to be achieved through controlled plasticization rather than low Tg, thereby maintaining heat storage ability and achieving high gloss.
4Temperature
If methods are used to reduce glass transition temperature (Tg) of the binder resin to achieve low-temperature fixing, then fixing temperature is reduced, but high gloss is insufficient
Solution Approach 1:
The patent uses binder resin with Tg of 80-120°C and molecular weight of 50,000-150,000, which provides appropriate melt viscosity for forming smooth, glossy surfaces during fixing. This parameter optimization ensures high gloss is achieved while maintaining low-temperature fixing capability.
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 optimized toner composition achieves a wide fusing latitude, high gloss, and improved storage stability, while ensuring low-temperature fixing and heat storage ability, by controlling the solubility parameters and domain distribution of the binder and releasing agents.
Implementation Method 1
where SP(Binder) is a solubility parameter [(J/cm3)0.5] of the binder resin, and SP(Wax) is a solubility parameter [(J/cm3)0.5] of the releasing agent
Data Source
AI summary
A toner for developing an electrostatic image including a binder resin, a coloring agent, and a releasing agent are provided. A particle of the toner satisfies conditions of Equation (1) (W(L)/T(L)≤0.1 and Equation (2) 15<Nstain, where Nstain refers to a number of stained releasing agent domains when the particle of the toner is stained with ruthenium tetraoxide (RuO4) and a cross section of the particle of the toner is observed, W(L) refers to a longest length of lengths of the stained releasing agent domains, and T(L) refers to a longest length of the cross section of the particles of the toner.