Toner with Organic-Inorganic Composite Additives for Low-Temperature Fixing
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Solution Overview
Problem
Electrophotographic toners face challenges in achieving low-temperature fixability while maintaining developing properties, as external additives with large particle diameters tend to embed into the toner surface, leading to image defects and contamination issues.
Innovation Solution
A toner composition featuring organic-inorganic composite fine particles with a specific volumetric specific heat range and particle size, embedded within a vinyl resin, helps maintain low-temperature fixability and prevents external additive embedding, ensuring stable image density and reduced contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an external additive having a large particle diameter is used to hinder embedding, then developing properties are maintained, but low-temperature fixability deteriorates due to increased heat capacity
Solution Approach 1:
The patent changes the particle diameter parameter of the external additive from large (conventional) to small (0.03-0.2 μm), which fundamentally alters the heat capacity characteristics. This parameter change enables the external additive to maintain developing properties while having minimal impact on low-temperature fixability, as smaller particles contribute less to the overall heat capacity of the toner composition.
Solution Approach 2:
The patent uses a composite external additive consisting of inorganic fine particles (such as silica, alumina, or titanium oxide) combined with organic particles. This composite structure allows optimization of both developing properties and thermal characteristics, as the inorganic component provides durability and charge retention while the organic component can be selected to match thermal properties with the binder resin, improving low-temperature fixability.
2Productivity
If an external additive having a large particle diameter is used, then speed and life are improved, but the external additive detaches from the toner surface causing parts contamination
Solution Approach 1:
The patent changes the particle diameter parameter from large to small (0.03-0.2 μm), which improves adhesion to the toner surface. The smaller particle size increases the surface area contact and mechanical interlocking with the toner particles, preventing detachment during the electrophotographic process and eliminating the contamination problem while maintaining productivity benefits.
Solution Approach 2:
The composite structure of inorganic and organic particles creates a synergistic effect where the inorganic core provides structural stability and the organic coating enhances adhesion to the toner surface. This composite external additive maintains its position on the toner during high-speed operation and extended use, preventing the detachment and contamination issues associated with larger particle additives.
3Ease of operation
If inorganic fine particles with large particle diameter are added, then toner fluidity is improved, but gaps among toner particles increase inhibiting thermal fusion
Solution Approach 1:
The patent changes the particle diameter parameter to a small range (0.03-0.2 μm), which allows the external additive to fill inter-particle spaces rather than create gaps. This size optimization maintains toner fluidity by preventing aggregation while ensuring sufficient thermal contact between toner particles during fixing, enabling proper thermal fusion without the gap formation problem caused by larger particles.
Data Source
AI summary
Provided is a toner that has excellent low-temperature fixability and is capable of obtaining an image having a stable image density, in which the occurrence of image defects is suppressed. The toner includes toner base particles, each of which contains a binder resin and a magnetic material, and organic-inorganic composite fine particles on each of the toner base particles. Each of the organic-inorganic composite fine particles comprises a vinyl resin particle, and inorganic fine particles which are embedded in the vinyl resin particle, and at least a part of which are exposed. The volumetric specific heat of the organic-inorganic composite fine particles and the volumetric specific heat of the toner base particles satisfy a predetermined provision.