Silicone Oil-Treated Silica Particles for Toner Agglomeration Control
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Solution Overview
Problem
High-speed and high-resolution photocopiers and printers face issues with agglomeration in toners containing silica as an external additive, leading to 'color missing' and 'density irregularity' during printing.
Innovation Solution
A silicone oil-treated silica particle with a BET specific surface area of 70 m2/g to 120 m2/g, surface-treated with 2.0 mass % to 5.0 mass % free silicone oil, and added as an external additive to styrene acrylic resin particles, achieving a degree of agglomeration of 18% or less, enhances toner flowability and reduces agglomeration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If silica is used as an external additive to improve toner flowability and charging characteristics, then toner performance is improved, but toner agglomeration occurs during high-speed printing leading to color missing and density irregularity
Solution Approach 1:
The patent changes the surface area parameter of silica particles from conventional large surface area (200-400 m2/g) to a specific range (70-120 m2/g). This parameter change reduces the total surface area available for silica-silica interactions, thereby reducing agglomeration tendency while maintaining sufficient surface area for effective surface treatment with silicone oil and proper toner performance
Solution Approach 2:
The patent creates a composite structure by surface-treating silica particles with silicone oil. This composite material combines the flowability-enhancing properties of silica with the lubricating and dispersing properties of silicone oil, achieving both good toner flowability and reduced agglomeration during high-speed printing
2Productivity
If printing speed is increased to meet high-performance requirements, then productivity is improved, but toner agglomeration increases causing color missing and density irregularity
Solution Approach 1:
The patent modifies the silica particle surface area parameter to 70-120 m2/g, which reduces agglomeration tendency. This allows the toner to maintain stable properties even during high-speed printing operations, enabling both high productivity and consistent image quality
Solution Approach 2:
Silicone oil acts as an intermediary substance on the silica particle surface. It provides a lubricating effect that prevents toner particles from adhering to each other during high-speed transport, thereby maintaining image quality while enabling high printing speeds
3Reliability
If silica particle surface area is increased to improve surface treatment effectiveness, then charging characteristics are improved, but agglomeration tendency increases
Solution Approach 1:
The patent optimizes the silica surface area parameter to a balanced range of 70-120 m2/g. This moderate surface area provides sufficient sites for silicone oil attachment and maintains stable charging characteristics, while avoiding excessive surface area that would lead to strong silica-silica attractions and agglomeration
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 silicone oil-treated silica particles significantly reduce toner agglomeration, minimizing 'color missing' and 'density irregularity' while maintaining high print quality by improving toner flowability and charging characteristics.
Implementation Method 1
The silica particle body has been surface-treated with the silicone oil. The amount of free silicone oil liberated from the surface of the silica particle body in the silicone oil accounts for 2.0 mass % to 5.0 mass % with respect to the silica particle body.
Implementation Method 2
A surface-treated styrene acrylic resin particle, in which 2 parts by mass of the silicone oil-treated silica particle has been added to 100 parts by mass of a styrene acrylic resin particle having a particle size median of 5 μm to 8 μm, has a degree of agglomeration of 18% or less.
Data Source
AI summary
A silicone oil-treated silica particle according to the present invention includes a silica particle body and silicone oil. The silica particle body has a BET specific surface area of 70 m2/g to 120 m2/g. The silica particle body has been surface-treated with the silicone oil. The amount of free silicone oil liberated from the surface of the silica particle body in the silicone oil accounts for 2.0 mass % to 5.0 mass % with respect to the silica particle body. A surface-treated styrene acrylic resin particle, in which 2 parts by mass of the silicone oil-treated silica particle has been added to 100 parts by mass of a styrene acrylic resin particle having a particle size median of 5 μm to 8 μm, has a degree of agglomeration of 18% or less.