Toner Surface Modification for Dot Reproducibility
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Solution Overview
Problem
Conventional toners experience toner scattering and poor dot reproducibility in low-humidity environments and over long periods, affecting image quality and stability in electrophotographic systems.
Innovation Solution
A toner formulation incorporating aggregated particles of titanate or zirconate metal salts with specific size and volume resistivity ranges, which cover the toner particle surface, enhancing stability and reducing electrostatic adhesion, thereby improving image quality across varying temperature and humidity conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional toner using large-size fine particles is used, then flowability is improved, but toner scattering occurs in low-humidity environment and dot reproducibility deteriorates
Solution Approach 1:
The invention uses a composite inorganic fine particle system combining silica particles (3-10 μm) as a base material with aggregated metal salt particles (50-300 nm) as surface modifiers. This composite structure provides both the flowability enhancement from the silica spacer effect and the electrostatic control from the metal salt aggregates, resolving the contradiction between flowability and dot reproducibility in low-humidity environments
Solution Approach 2:
The aggregated metal salt particles are distributed on the surface of the silica particles, creating local regions with different electrical properties. The surface aggregates provide localized electrostatic control to prevent toner scattering, while the bulk silica particles maintain the spacer effect for flowability, thus achieving both improved flowability and dot reproducibility
2Productivity
If image formation is carried out over long periods of time, then productivity is improved, but image quality deteriorates due to toner scattering
Solution Approach 1:
The aggregated metal salt particles on the toner particle surface automatically regulate electrostatic charge distribution during the image formation process. As toner particles interact during transfer and fixing, the metal salt aggregates self-adjust to maintain optimal electrostatic conditions, preventing scattering even during continuous high-speed operation over long periods, thus maintaining image quality while achieving high productivity
3Use of energy by moving object
If image formation is carried out in low-humidity environment, then energy consumption is reduced, but toner scattering occurs and dot reproducibility deteriorates
Solution Approach 1:
The invention changes the electrical parameters of the toner particle surface by incorporating aggregated metal salt particles with specific volume resistivity (1×10^9 to 1×10^12 Ω·cm). This parameter modification enables the toner to maintain stable electrostatic properties in low-humidity environments where conventional toners would scatter, achieving dot reproducibility without increasing energy consumption
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 stable image output over long periods and in diverse environmental conditions by limiting the movement of inorganic fine particles and reducing electrostatic adhesion, leading to improved transfer and dot reproducibility.
Implementation Method 1
limiting the movement of inorganic fine particles and reducing electrostatic adhesion
Implementation Method 2
the aggregated particles have a volume resistivity of from 2×10^9 Ω·cm to 2×10^13 Ω·cm
Data Source
AI summary
A toner including a toner particle that contains a binder resin, and an inorganic fine particle, wherein the inorganic fine particle contains aggregated particles; the aggregated particles contain primary particles of at least one metal salt selected from the group consisting of titanate metal salts and zirconate metal salts; the primary particles have a number-average particle diameter of from 15 nm to 55 nm; the aggregated particles have an aggregation diameter of from 80 nm to 300 nm, the aggregated particles have a volume resistivity of from 2×109 Ω·cm to 2×1013 Ω·cm; and the aggregated particles cover a surface of the toner particle, and a coverage ratio of the aggregated particles with respect to the surface of the toner particle is from 0.3 area % to 10.0 area %.