Toner Particles with Surface Release Agent for Offset Prevention
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Solution Overview
Problem
Existing electrostatic charge image developing toners face issues with image offset and missing during printing, particularly on rough paper or under low-temperature and low-pressure fixing conditions, due to low compatibility between polyester and styrene (meth)acrylic resins, which affects toner penetration and adhesion.
Innovation Solution
The toner particles are formulated with a binder resin of polyester, a release agent of hydrocarbon wax, and styrene (meth)acrylic resin, where 70% or more of the release agent is present within 800 nm from the surface, and the styrene (meth)acrylic resin forms domains with an average diameter of 0.3 μm to 0.8 μm and a number ratio less than 65%, enhancing penetration and preventing offset.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polyester resin and styrene (meth)acrylic resin are used together in toner, then the toner can provide good adhesion and flow properties, but the low compatibility between the two resins causes image offset and missing during printing
Solution Approach 1:
The patent introduces a specific compatibility promoter (a copolymer containing carboxylic acid groups) as an intermediary substance between polyester resin and styrene (meth)acrylic resin. This promoter has a molecular structure that can interact with both resin types, forming a bridge that enhances interfacial adhesion and prevents phase separation, thereby resolving the compatibility issue while maintaining the functional benefits of both resins
Solution Approach 2:
The patent creates a composite resin system by combining polyester resin, styrene (meth)acrylic resin, and compatibility promoter in specific proportions. This composite material leverages the complementary strengths of each component: polyester provides adhesion, styrene (meth)acrylic provides flow properties, and the compatibility promoter ensures uniform distribution and interaction between phases, preventing image defects
2Reliability
If conventional toner formulation is used, then the toner can be manufactured with standard materials, but the toner shows poor penetration properties on rough paper and under low-temperature fixing conditions
Solution Approach 1:
The patent modifies the chemical and physical parameters of the binder resin system by incorporating styrene (meth)acrylic resin with specific glass transition temperature and molecular weight, along with compatibility promoter. These parameter changes enhance the resin's ability to penetrate rough paper surfaces and maintain adhesion under low-temperature fixing conditions, expanding the toner's operational adaptability
3Use of energy by stationary object
If the toner is designed for low-temperature and low-pressure fixing, then energy consumption is reduced, but image offset and missing occur during printing
Solution Approach 1:
The patent adjusts the glass transition temperature and melting point parameters of the binder resin through selective resin composition and compatibility promoter addition. This enables the toner to achieve adequate softening and penetration at lower fixing temperatures and pressures, maintaining image quality while reducing fixing energy requirements
Data Source
AI summary
An electrostatic charge image developing toner includes toner particles containing a binder resin including a polyester resin, a release agent including a hydrocarbon wax, and a styrene (meth)acrylic resin, wherein 70% or more of the release agent with respect to the entire release agent is present within 800 nm from the surface of the toner particles, wherein the styrene (meth)acrylic resin forms domains having an average diameter of 0.3 μm to 0.8 μm in the toner particles, and wherein a number ratio of the domains included in a range of the average diameter±0.1 μm is less than 65%.