Electrostatic Toner Shell Layer Domain Design for Temperature Performance
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Solution Overview
Problem
Existing electrostatic latent image developing toners face challenges in achieving both high-temperature preservability and low-temperature fixability, as they often have non-homogenous structures that affect bonding and separation properties.
Innovation Solution
The toner particles are designed with a shell layer comprising first and second domains, each containing specific copolymers with distinct mole fractions and common monomers, resulting in a balanced polymer SP value difference and glass transition points, enhancing bonding and separation under varying temperature conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the shell layer has a non-homogenous structure with different resin compositions, then the toner achieves good bonding and separation properties, but the toner exhibits poor high-temperature preservability and poor low-temperature fixability
Solution Approach 1:
The shell layer is divided into first and second domains with different copolymer compositions. The first domain contains a first copolymer with specific monomer ratios, while the second domain contains a second copolymer with different monomer ratios. This local differentiation allows each domain to contribute specific properties: the first domain provides bonding characteristics while the second domain provides separation characteristics, yet both domains maintain compatible SP values to ensure overall toner stability across temperature ranges.
Solution Approach 2:
The toner shell layer is constructed as a composite structure containing two different copolymers with distinct monomer compositions. The first copolymer and second copolymer are both incorporated into the shell layer, creating a composite material system. The key is that both copolymers have SP values within 5.0 of each other, ensuring compatibility and preventing phase separation, while their different compositions provide the dual functionality of bonding and separation with improved temperature performance.
2Reliability
If the polymer SP value difference between main monomers is increased, then the bonding and separation properties are enhanced, but the toner stability deteriorates
Solution Approach 1:
The invention optimizes the polymer SP value difference parameter by controlling the monomer composition ratios. The first copolymer contains first main monomers and first additional monomers with specific mole fractions, while the second copolymer contains second main monomers and second additional monomers with different mole fractions. The polymer SP value difference between the first main monomers and second main monomers is maintained within the range of 0.5 to 5.0, which is sufficient to provide bonding and separation properties while preventing excessive phase separation that would compromise toner stability.
Data Source
AI summary
An electrostatic latent image developing toner includes toner particles each including a toner core and a shell layer. The shell layer includes first and second domains. The first domain includes a first copolymer of a first main monomer having a mole fraction of at least 20 mol % and one or more first additional monomers each having a mole fraction of less than 20 mol %. The second domain includes a second copolymer of a second main monomer having a mole fraction of at least 20 mol % and one or more second additional monomers each having a mole fraction of less than 20 mol %. A difference in polymer SP value between the first and second main monomers is at least 0.5 and no greater than 5.0. The first and second additional monomers each include one or more common monomers having a homopolymerization glass transition point of no greater than −20° C.