Sea-Island Toner Particles for Offset Reduction on Textured Media
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Solution Overview
Problem
Existing electrostatic charge image developing toners face challenges in forming high-intensity half-tone images on recording media with significant concavity and convexity, leading to issues like toner offset and image contamination due to uneven heat and pressure distribution during the fixing process.
Innovation Solution
The toner particles are designed with a sea-island structure, containing a polyester resin sea part and a vinyl resin island part, along with a first and second release agent, where the cross-sectional area ratio of the second release agent to the first release agent is between 0.2 and 0.8, allowing for controlled release agent supply based on external stimuli, thereby improving image intensity and reducing offset.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional toner structure is used, then the manufacturing process is simple, but the image intensity on recording media with concavity and convexity is insufficient
Solution Approach 1:
The toner particle is divided into a sea-island structure where the binder resin forms a continuous sea phase and the release agent forms dispersed island phases. This segmentation allows different regions of the toner to perform different functions: the binder resin provides structural integrity and adhesion, while the release agent islands control toner release behavior on convex and concave surfaces differently, thereby improving image intensity on uneven recording media.
Solution Approach 2:
The release agent is distributed non-uniformly throughout the toner particle with specific concentration zones (island phases embedded in sea phases). This local quality variation ensures that release agents are positioned optimally to interact with convex surfaces while allowing binder resin to dominate in regions that contact concave surfaces, resolving the contradiction between image intensity and structural complexity.
2Manufacturing precision
If heat and pressure are increased during fixing to improve image intensity, then image intensity improves, but toner offset and image contamination increase
Solution Approach 1:
The invention changes the physical and chemical parameters of the toner composition by incorporating specific release agents with controlled melting points and distribution patterns. The release agents lower the effective melting temperature of the toner at convex surfaces, allowing image intensity to improve at lower fixing temperatures and pressures, thereby preventing toner offset and contamination that would occur at higher temperatures.
Solution Approach 2:
The release agent acts as an intermediary substance between the toner particle and the recording medium surface. During the fixing process, the release agent migrates to the toner surface and interfaces with the recording medium, mediating the interaction to prevent excessive adhesion that causes offset while still allowing sufficient bonding for image intensity.
3Manufacturing precision
If the recording medium surface is smoothed to improve image quality, then image intensity improves, but the process complexity and cost increase
Solution Approach 1:
The toner particle structure is designed to be self-adaptive to the recording medium surface topography without requiring external surface treatment processes. The sea-island structure with distributed release agents enables the toner to automatically adjust its release characteristics based on whether it contacts convex or concave surfaces, achieving consistent image quality directly from the original recording medium surface.
Data Source
AI summary
An electrostatic charge image developing toner includes toner particles containing a binder resin containing a polyester resin forming a sea part and a vinyl resin forming an island part of a sea-island structure, a first release agent existing in the sea part in a domain state, and a second release agent existing in the island part in a domain state, wherein when a cross-sectional area of the second release agent is set to A1 and a cross-sectional area of the first release agent is set to B1 in a cross section of the toner particles, a relationship of 0.2≦A1/B1≦0.8 is satisfied.