Toner Particles with Gradient Charge Agents for Offset Resistance
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Solution Overview
Problem
Existing toners for developing electrostatic latent images face challenges with irregular particle shapes leading to inadequate image quality, impaired flowability, and increased toner consumption, which results in high running costs and complex image transfer processes, especially in high-temperature and high-humidity environments.
Innovation Solution
A toner composition with specific particle abundance and declining rate measurements, using metal or halogen particles as charge-controlling agents, ensures even deposition and improved fixability, offset resistance, and storage stability, while maintaining low toner scattering and high charging properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional toners are used in high-temperature and high-humidity environments, then image formation is possible, but color dots are formed due to fixing failure and charge distribution becomes unstable
Solution Approach 1:
The patent applies local quality by creating a toner particle structure with non-uniform charge distribution. The surface portion contains a higher concentration of charge-controlling agent particles compared to the internal portion, establishing a gradient structure. This local concentration difference enables the surface to effectively control charge distribution during development, preventing color dots in high-temperature and high-humidity environments while maintaining reliable fixing performance.
2Ease of manufacture
If irregular particle shape toners are used, then manufacturing is simpler, but image quality deteriorates and flowability is impaired
Solution Approach 1:
The patent employs spheroidality by specifying that toner particles have a spherical shape with a roundness of 0.93 or higher. This spherical morphology significantly improves flowability and transfer uniformity, thereby enhancing image quality. The spherical shape is achieved through controlled polymerization processes that enable uniform particle formation, resolving the contradiction between manufacturing simplicity and image quality by providing a reproducible synthesis method for spherical particles.
3Productivity
If toner scattering is reduced, then transfer efficiency improves, but charging properties must be maintained
Solution Approach 1:
The patent applies parameter changes by optimizing multiple critical parameters: particle size distribution (volume average diameter 3.0-7.0 μm with specific standard deviation), charge-controlling agent concentration gradient (higher at surface, lower internally), and particle roundness (0.93 or higher). These parameter optimizations work synergistically to reduce toner scattering during transfer while maintaining excellent charging properties through the surface-enriched charge-controlling agent distribution, achieving both high transfer efficiency and reliable charging.
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 excellent low-temperature fixability, hot-offset resistance, and heat-resistant storage stability with minimized toner scattering, enhancing image quality and transfer efficiency while reducing material consumption and apparatus size.
Implementation Method 1
The particles are metal particles, or halogen particles, or a combination of the metal particles and the halogen particles... used for developing an electrostatic latent image
Implementation Method 2
measured by a scanning electron microscope-energy dispersive X-ray spectrometer (SEM-EDX)
Data Source
AI summary
A toner includes toner particles. Each toner particle includes a binder resin, a release agent, a colorant, and particles. The particles are metal particles, or halogen particles, or both. A metal constituting the metal particles may have a monovalent or higher ionic valence. An abundance X of the particles is within a range represented by 3 μm2≤X μm2≤10 μm2. X μm2 is the abundance X that is an area of the particles present in a surface portion of each of the toner particles as measured by SEM-EDX with setting acceleration voltage to 1 kV. A declining rate of the particles is 80% to 100%. Y μm2 is an abundance Y that is an area of the particles present in a surface portion of each of the toner particles as measured by the SEM-EDX with setting acceleration voltage to 3 kV.