Toner with Surface Wax Domains for Low-Temperature Fixing
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Solution Overview
Problem
Existing toners face challenges in achieving low-temperature fixability while maintaining developability in high-temperature, high-humidity environments, as they tend to soil non-image regions due to uneven wax distribution and charge distribution issues.
Innovation Solution
A toner composition with a resin component and wax, featuring inorganic fine particles on the surface with specific volume resistivity and relative permittivity, which facilitates uniform charge distribution and prevents soiling by controlling the occupation area percentage and size of wax domains.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the glass transition temperature of the resin component is lowered to improve low-temperature fixability, then the low-temperature fixability is improved, but the storage stability with respect to heat deteriorates
Solution Approach 1:
The invention applies local quality by creating an uneven distribution of wax specifically in the surface vicinity of toner particles. The surface region contains wax at 3-15 mass% to facilitate low-temperature melting and fixing, while the internal region maintains resin composition for storage stability. This spatial differentiation allows the surface to have low-temperature fixability while the core preserves heat storage stability during storage.
2Temperature
If wax is unevenly distributed in the surface vicinity of each toner particle to improve low-temperature fixability, then rapid melting during fixing is achieved, but developability deteriorates after standing in high-temperature, high-humidity environment
Solution Approach 1:
The invention applies parameter changes by precisely controlling the wax content parameter within the range of 3-15 mass% in the surface vicinity. This specific parameter range optimizes the balance between low-temperature fixability and developability. Additionally, the invention controls the depth of wax distribution to 0.05-2.0 μm from the surface, creating an optimal parameter configuration that prevents both excessive melting and insufficient fixing performance.
Solution Approach 2:
The invention applies local quality by creating an uneven distribution of wax specifically in the surface vicinity of toner particles. The surface region contains wax at 3-15 mass% to facilitate low-temperature melting and fixing, while the internal region maintains resin composition for storage stability. This spatial differentiation allows the surface to have low-temperature fixability while the core preserves heat storage stability during storage.
3Temperature
If heat is transferred to paper or air in low-temperature environment, then the available heat for fixing decreases, but fixing at low temperature becomes difficult
Solution Approach 1:
The invention applies phase transitions by utilizing the melting behavior of wax at low temperatures. The wax component undergoes phase transition from solid to liquid at relatively low temperatures (melting point 40-80°C), enabling the toner surface to soften and adhere to the substrate without requiring high fixing temperatures. This phase transition mechanism allows efficient heat utilization in low-temperature fixing conditions.
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 and excellent developability without soiling non-image regions, even after prolonged exposure to high-temperature, high-humidity conditions.
Implementation Method 1
the inorganic fine particle contains a fine particle A having a volume resistivity of 1.0×10³ to 3.0×10⁵ Ω·cm
Implementation Method 2
having a relative permittivity εr of 100 or more
Implementation Method 3
toners in which the surface vicinity of each toner particle is made to readily melt so that all toner particles are caused to readily and rapidly melt during fixing
Data Source
AI summary
A toner comprising: a toner particle containing a resin component and a wax; and an inorganic fine particle on the surface of the toner particle, wherein, in a cross section of the toner particle, domains containing the wax are observed, and when among the domains, domains having a major diameter of 10-300 nm are defined as domains S, an occupation area percentage of which a ratio of a total sum of areas occupied by the domains S in a region from a surface of the toner particle to a depth of 600 nm in the cross section with respect to an area of the region, is 3.0-15.0%, and wherein the inorganic fine particle contains a fine particle A having a volume resistivity of 1.0×103 to 3.0×105 Ω·cm, and having a relative permittivity εr of 100 or more.