External Additive Particle Composition for Stable Toner Flowability
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Solution Overview
Problem
Existing toners face challenges in maintaining high flowability and image density stability, particularly in high-speed printing and low-humidity environments, as they tend to lose flowability over time and exhibit variations in image density.
Innovation Solution
The development of external additive particles containing a polymer with specific ratios of sulfur, nitrogen, silicon, carbon, oxygen atoms, and siloxane moieties, which enhance electrostatic interaction and charge balance to improve flowability retention and image density stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a toner is prepared to contain a toner additive having an organic polymer skeleton and a polysiloxane skeleton, then flowability of the toner is improved, but temporal change in flowability during output of images for a long time and stability of image density in low-humidity environments require further improvement
Solution Approach 1:
The patent changes the chemical composition parameters of the external additive particles by specifying precise atomic ratios (Si/(C+O+Si) = 4.0-25.0%, N/(C+N+O+Si+S) = 0.40-2.50%, S/(C+N+O+Si+S) = 0.05-0.25%) to optimize both flowability and long-term stability. This parameter optimization resolves the contradiction by finding the precise compositional balance that delivers immediate flowability improvement while ensuring temporal retention and density stability.
Solution Approach 2:
The patent creates composite external additive particles that integrate multiple functional elements (silicon from siloxane groups for flowability, nitrogen and sulfur for electrostatic interaction and charge balance) into a single coordinated structure. This composite approach allows the material to simultaneously provide improved flowability and enhanced reliability for flowability retention and density stability that neither component could achieve alone.
2Ease of operation
If external additive particles with higher silicon content are used to improve flowability, then flowability is enhanced, but image density stability in low-humidity environments deteriorates
Solution Approach 1:
The patent optimizes the silicon content parameter within a specific range (Si/(C+O+Si) = 4.0-25.0%) rather than maximizing it. This controlled parameter change ensures sufficient flowability improvement while preventing excessive silicon content that would harm image density stability in low-humidity environments.
Solution Approach 2:
The patent introduces nitrogen and sulfur elements at specific surface locations of the external additive particles to provide localized electrostatic interaction capabilities. This local quality enhancement (surface charge balance) compensates for the potential negative effects of silicon on density stability, allowing both flowability and density stability to coexist.
3Reliability
If external additive particles with higher nitrogen content are used to improve electrostatic interaction, then charge balance is enhanced, but flowability retention during long-term use deteriorates
Solution Approach 1:
The patent optimizes nitrogen content within a balanced range (N/(C+N+O+Si+S) = 0.40-2.50%) that provides sufficient electrostatic interaction for charge balance while preventing excessive nitrogen that would compromise flowability retention. This balanced parameter setting resolves the contradiction between charge balance and flowability retention.
Solution Approach 2:
The patent creates a composite structure where nitrogen (for charge balance) and silicon (for flowability) work synergistically. The coordinated presence of multiple elements in specific proportions ensures that charge balance enhancement does not come at the expense of flowability retention.
4Ease of operation
If external additive particles with higher sulfur content are used to improve flowability retention, then temporal stability is enhanced, but image density stability in low-humidity environments deteriorates
Solution Approach 1:
The patent optimizes sulfur content within a controlled range (S/(C+N+O+Si+S) = 0.05-0.25%) that provides sufficient flowability retention while preventing excessive sulfur that would harm image density stability in low-humidity environments. This precise parameter control resolves the contradiction between flowability retention and density stability.
Solution Approach 2:
The patent positions sulfur atoms at specific surface locations of the external additive particles to provide localized electrostatic interactions that enhance flowability retention without causing bulk property changes that would affect image density stability.
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 external additive particles provide high flowability retention during long-term use and stabilize image density in low-humidity conditions, ensuring consistent print quality.
Implementation Method 1
enhance electrostatic interaction and charge balance to improve flowability retention and image density stability
Implementation Method 2
a polymer containing a sulfur atom and a nitrogen atom, wherein the polymer includes a vinyl polymer moiety and a siloxane moiety
Data Source
AI summary
External additive particles including a polymer containing a sulfur atom and a nitrogen atom, wherein the polymer includes a vinyl polymer moiety and a siloxane moiety, relative to a total number of carbon atoms, oxygen atoms, and silicon atoms constituting the external additive particles, a ratio of a number of the silicon atoms constituting the external additive particles is 4.0% or more and 25.0% or less, and in surfaces of the external additive particles analyzed by X-ray photoelectron spectroscopy, relative to a total number of carbon atoms, nitrogen atoms, oxygen atoms, silicon atoms, and sulfur atoms, a ratio of a number of the nitrogen atoms is 0.40% or more and 2.50% or less, and a ratio of a number of the sulfur atoms is 0.05% or more and 0.25% or less.