Toner with Surface Wax Domains for Fixing and Flowability
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Solution Overview
Problem
Toner particles with wax unevenly distributed near the surface exhibit superior low-temperature fixability but tend to cause image lacks in high-temperature and high-humidity environments due to embedded inorganic fine particles, which impair flowability and charging efficiency.
Innovation Solution
A toner particle structure with a specific distribution of small and coarse wax domains near the surface, where small wax domains (10-120 nm) occupy 2.0-15.0% of the surface area and have a ratio of 0.60 or more to the total wax domains, minimizing inorganic fine particle embedding and maintaining flowability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If wax is unevenly distributed near the surface of toner particles, then low-temperature fixability is improved, but image lacks occur in high-temperature and high-humidity environments
Solution Approach 1:
The patent applies local quality by creating distinct regions within the toner particle: a surface region (0-600 nm depth) containing wax domains with specific size distribution (2.0≤R1≤15.0% and R1/R2≥0.60) for low-temperature fixing, and an internal region containing inorganic fine particles for image quality stability. This spatial differentiation of composition resolves the contradiction between surface melting behavior and overall particle stability.
2Manufacturing precision
If inorganic fine particles are embedded in toner particles, then charging efficiency is improved, but flowability deteriorates
Solution Approach 1:
The patent segments the toner particle into distinct zones: inorganic fine particles are confined to the internal region (deeper than 600 nm from surface) rather than being uniformly distributed or embedded throughout. This segmentation allows charging functionality to be maintained through particle composition while preventing flowability degradation by avoiding excessive embedding that would increase inter-particle friction.
3Temperature
If glass transition temperature of resin component is lowered, then low-temperature fixability is improved, but high-temperature storage stability deteriorates
Solution Approach 1:
The patent changes the physical state parameters of the resin component by controlling the glass transition temperature through resin selection and composition. By carefully selecting resin types and adjusting their Tg values, the patent achieves optimal low-temperature fixing while maintaining high-temperature storage stability, complementing the wax domain strategy.
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 superior low-temperature fixability while preventing image lacks in high-temperature and high-humidity environments by ensuring adequate charging and flowability through controlled wax domain distribution.
Implementation Method 1
a toner particle can melt easily near its surface so that the entire toner particle can melt rapidly when fixed
Implementation Method 2
part of the heat quantity necessary for fixing is used to evaporate water from the paper
Data Source
AI summary
A toner comprises a toner particle containing a resin component and a wax; and an inorganic fine particle on a surface of the toner particle, wherein in the cross section of the toner particle, domains including the wax are present in a region ranging from a surface of the toner particle to a depth of 600 nm from the surface, wherein when a percentage ratio of sum of areas of all the domains in the region with respect to an area of the region is R2, and when a percentage ratio of sum of areas of the domains having a major diameter of 10 to 120 nm in the region with respect to the area of the region is R1, R1 and R2 satisfy the following formulae (1) and (2):2.0≤R1(%)≤15.0 formula(1)R1(%)/R2(%)≥0.60 formula (2).