Electrostatic Toner Particle Control for Humid-Condition Transfer
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Solution Overview
Problem
Existing electrostatic charge image developing toners face challenges in achieving high transferability of solid images in high-temperature and high-humidity environments due to non-electrostatic adhesion forces and partial toner aggregation.
Innovation Solution
The toner composition is optimized with specific particle size and circularity distributions, incorporating a halogen element, particularly bromine, to enhance electron retention and reduce charge leakage, resulting in improved transferability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the existence proportion of particles having a particle size of 4.5 μm or more and 7.5 μm or less and a circularity of less than 0.930 is less than 0.1% by number, then the transferability of solid image is improved, but the toner aggregation increases due to insufficient high-circularity particles for dense packing
Solution Approach 1:
The patent applies parameter changes by precisely controlling the particle size and circularity distribution parameters. Specifically, it sets the existence proportion of particles with 4.5-7.5 μm size and circularity 0.950-0.990 to 40-80% by number, and particles with circularity 0.930-0.950 to 10-50% by number. This optimized parameter combination resolves the contradiction by enabling dense packing (reducing aggregation) while maintaining low non-electrostatic adhesion (improving transferability).
Solution Approach 2:
The patent employs a composite particle size and shape distribution strategy. Instead of using uniform particles, it creates a composite system with multiple particle categories: high-circularity particles (0.950-0.990) for dense packing, medium-circularity particles (0.930-0.950) for filling gaps, and controlled low-circularity particles (<0.930) limited to 0.1-10% by number. This composite approach balances the competing requirements of reducing aggregation and minimizing non-electrostatic adhesion.
2Stability of the object's composition
If the existence proportion of particles having a particle size of 4.5 μm or more and 7.5 μm or less and a circularity of more than 0.950 and less than 0.990 is 59% by number or more, then the high-circularity particles provide good packing, but the non-electrostatic adhesion force increases reducing transferability
Solution Approach 1:
The patent optimizes the parameter range of high-circularity particles by limiting them to 40-80% by number (not exceeding 80%), and combines this with medium-circularity particles (0.930-0.950) at 10-50% by number. This balanced parameter distribution achieves dense packing while controlling non-electrostatic adhesion forces that would otherwise increase with excessive high-circularity particles.
Solution Approach 2:
The patent applies local quality by differentiating the functional roles of different particle categories within the toner composition. High-circularity particles (0.950-0.990) serve primarily for dense packing in core regions, while medium-circularity particles (0.930-0.950) fill intermediate spaces, and low-circularity particles (<0.930) are strictly limited (0.1-10% by number) to minimize non-electrostatic adhesion. This localized functional assignment resolves the contradiction between packing density and transferability.
3Reliability
If the toner particles contain halogen element with abundant amount of 0.25 millimoles or more and 12.5 millimoles or less per 100 g, then the electron retention is enhanced and charge leakage is reduced, but the manufacturing complexity increases
Solution Approach 1:
The patent applies parameter changes by specifying a quantitative range for halogen element content (0.25-12.5 millimoles per 100 g toner). This parameter optimization ensures sufficient electron retention capability while avoiding excessive halogen content that would complicate manufacturing and potential environmental issues. The defined range balances performance requirements with manufacturing feasibility.
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 enhanced transferability of solid images in high-temperature and high-humidity conditions by minimizing non-electrostatic adhesion and reducing toner aggregation, ensuring high-density packing and efficient image transfer.
Implementation Method 1
incorporating a halogen element, particularly bromine, to enhance electron retention and reduce charge leakage
Data Source
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AI summary
An electrostatic charge image developing toner contains toner particles, in which, with respect to entire particles of the electrostatic charge image developing toner, an existence proportion of particles having a particle size of 4.5 µm or more and 7.5 µm or less and a circularity of less than 0.930 is 0.1% by number or more and 5.0% by number or less, and an existence proportion of particles having a particle size of 4.5 µm or more and 7.5 µm or less and a circularity of more than 0.950 and less than 0.990 is 59% by number or more and 80% by number or less.