Shell-Layer Toner Structure for Stable Charge and Low Adhesion
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Solution Overview
Problem
Existing toners for electrostatic latent image development face challenges in achieving satisfactory heat-resistant preservation properties and low-temperature fixing properties, while maintaining stable chargeability and preventing adhesion to photosensitive drums and intermediate transfer belts, especially in varying environmental conditions.
Innovation Solution
The toner comprises a core particle coated with a shell layer formed from resin fine particles, including a sea-like region of smaller particles containing a quaternary ammonium compound and island-like bumps of larger silicone resin particles, providing a positively chargeable surface with improved mechanical strength and reduced adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a shell layer is formed to improve heat-resistant preservation properties and low-temperature fixing properties, then preservation stability and fixing properties are improved, but the complexity of the toner structure increases
Solution Approach 1:
The shell layer is segmented into two distinct types of resin fine particles: first resin fine particles forming a continuous phase and second resin fine particles forming discrete bumps. This segmentation allows each component to perform its specific function - the first particles provide base coating and heat resistance, while the second particles provide low-temperature fixing points - thereby improving preservation stability and fixing properties without requiring a completely new complex structure
Solution Approach 2:
The shell layer exhibits local quality differentiation where the first resin fine particles provide general heat-resistant preservation properties across the surface, while the second resin fine particles create localized bumps with specific low-temperature fixing capabilities. This local differentiation allows the toner to achieve multiple performance goals through a unified shell layer structure
2Ease of operation
If inorganic fine powder is externally added to improve flowability and charging properties, then flowability and chargeability are improved, but the adhesion to photosensitive drum increases
Solution Approach 1:
The shell layer uses a composite system of two different resin fine particles - vinyl-based first particles and silicone-based second particles. This composite material approach combines the flowability-enhancing properties of the vinyl resin with the low-adhesion properties of silicone resin, achieving both good flowability and reduced adhesion to the photosensitive drum simultaneously
3Reliability
If shell layer coverage is increased to improve preservation stability, then preservation properties are improved, but transfer efficiency decreases
Solution Approach 1:
The shell layer is designed with local quality variation where the first resin fine particles provide continuous coverage for preservation stability, while the second resin fine particles are distributed as discrete bumps at controlled coverage ratios (10-50%). This local differentiation ensures that the continuous phase maintains preservation properties while the limited presence of silicone bumps prevents excessive adhesion that would hinder transfer efficiency
Data Source
AI summary
Toner for development of electrostatic latent images includes a toner particle having a toner core particle and a shell layer. The shell layer is formed of resin fine particles containing vinyl-based resin and including a plurality of types of first resin fine particles and second resin fine particles. The shell layer has a sea-like region formed of the plurality of types of first resin fine particles and island-like bumps formed of the second resin fine particles with a larger average particle size than the first resin fine particles. At least one type of first resin fine particles contains a quaternary ammonium compound and the second resin fine particles contain silicone resin. The average particle size of the second resin fine particles is from 70 nm to 150 nm, and the ratio of coverage of the surface of the toner core particle with the bumps is from 10% and 50%.