Toner Surface Layering for Image Streak Prevention
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Solution Overview
Problem
Existing toners for developing electrostatic charge images often suffer from color streaks and poor releasability between the fixing member and images due to stress-induced adhesion, which degrades the strength of the toner surface layers and leads to sticking issues.
Innovation Solution
A toner composition comprising binder resin, resin particles, and a releasing agent, where the loss coefficient at 60°C is less than 0.6 and the releasing agent is distributed near the surface layers with a specific area proportion, enhancing elasticity and reducing adhesion to photoreceptors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the loss coefficient tan δ(t) at 60°C is increased to improve releasability, then the toner becomes more elastic and releases better from the fixing member, but color streaks increase due to reduced surface layer strength
Solution Approach 1:
The patent applies local quality by creating a surface layer with specific releasing agent domains that have different properties from the bulk toner. The surface layer contains releasing agent domains with an area ratio of 30-70%, providing localized elasticity for releasability, while the bulk toner maintains higher strength to prevent color streaks. This spatial differentiation of properties resolves the contradiction between releasability and color streak prevention.
Solution Approach 2:
The patent changes the physical and chemical parameters of the toner by controlling the loss coefficient tan δ(t) at 60°C to be 0.25 or less and adjusting the releasing agent domain area ratio to 30-70%. These parameter changes optimize the balance between elasticity (for releasability) and surface layer strength (for preventing color streaks), resolving the technical contradiction.
2Reliability
If the releasing agent domains are concentrated at the surface to improve releasability, then the toner releases better from the fixing member, but the surface layer strength decreases leading to color streaks
Solution Approach 1:
The patent creates a surface layer with releasing agent domains having an area ratio of 30-70%, which provides localized elasticity for improved releasability. The bulk toner maintains higher strength characteristics, creating a gradient structure where the surface layer has optimized releasability properties without compromising overall structural integrity, thus preventing color streaks.
Solution Approach 2:
The patent creates a composite structure within the toner particles by combining binder resin, resin particles, and releasing agent in specific proportions and distributions. The releasing agent domains are distributed with 30-70% area ratio at the surface, creating a composite material structure that simultaneously provides releasability and maintains surface layer strength.
3Object-generated harmful factors
If the loss coefficient tan δ(t) is decreased to reduce color streaks, then surface layer strength is maintained, but releasability deteriorates due to reduced elasticity
Solution Approach 1:
The patent resolves this contradiction by creating local quality differences within the toner structure. The bulk toner has low loss coefficient (≤0.25) for high strength and low color streaks, while the surface layer contains releasing agent domains (30-70% area ratio) that provide localized elasticity for releasability. This spatial differentiation allows both requirements to be satisfied simultaneously.
Solution Approach 2:
The patent changes multiple parameters working together: loss coefficient tan δ(t) ≤ 0.25 for strength, and releasing agent domain area ratio of 30-70% for elasticity. This combination of parameter changes achieves both low color streaks (from low loss coefficient) and good releasability (from releasing agent domains), resolving the technical contradiction.
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 exhibits reduced color streaks and improved releasability by maintaining surface layer strength and elasticity, preventing sticking to photoreceptors under external stress.
Implementation Method 1
the loss coefficient tan δ(t) at 60° C. is 0.25 or less... exhibits reduced color streaks and improved releasability by maintaining surface layer strength and elasticity
Data Source
AI summary
A toner for developing an electrostatic charge image contains toner particles that contain a binder resin, resin particles, and a releasing agent, in which the toner has a loss coefficient tan δ(t) at 60° C. of less than 0.6, and, in cross sections of the toner particles, a proportion of an area of domains of the releasing agent present from surfaces of the toner particles to a depth of 1 μm relative to a total area of domains of the releasing agent is 30% or more and 70% or less.