Core-Shell Toner Resin Low-Temperature Fixing
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Solution Overview
Problem
There is a trade-off between low-temperature fixability and high transfer efficiency in existing toners, with halftone images having a low toner laid-on level failing to fix due to cold offsetting and increased toner scattering caused by the ester group-containing copolymer's elastic properties, leading to maintenance issues and contamination.
Innovation Solution
A toner with a core-shell structure is developed, where the core contains more than 50% ester group-containing olefin-based copolymer and the shell is an amorphous resin with a glass transition temperature of 50° C. to 70° C., enhancing low-temperature fixability and transfer efficiency while preventing toner scattering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If an ethylene-based ester group-containing copolymer is used as a thermoplastic elastomer resin to achieve low-temperature fixability, then low-temperature fixability is improved, but halftone images with low toner laid-on level cannot be fixed and cold offsetting occurs
Solution Approach 1:
The patent uses a composite resin system combining an ethylene-based ester group-containing copolymer (providing low-temperature fixability through low glass transition temperature) with a polyester resin (providing structural integrity and adhesion). This composite approach allows the toner to achieve both low-temperature fixability and reliable halftone image fixation without cold offsetting.
2Productivity
If an ethylene-based ester group-containing copolymer is used as a main binder, then excellent transfer efficiency is achieved, but volume resistance increases after long period inactivity and toner scattering occurs
Solution Approach 1:
The patent modifies the chemical composition parameters of the resin system by incorporating a polyester resin with specific functional groups that can form hydrogen bonds. This changes the intermolecular forces and electrostatic properties of the toner, maintaining low volume resistance even after long periods of inactivity, thereby preventing toner scattering while preserving high transfer efficiency.
3Temperature
If a crystalline polyester resin is used as a plasticizer for an amorphous polyester resin to achieve low temperature fixing, then low temperature fixability is improved, but viscosity decreases and fluidity decreases with increased adhesive properties during long term image output
Solution Approach 1:
The patent extracts the plasticizing function from the crystalline polyester resin and replaces it with an ethylene-based ester group-containing copolymer that provides low-temperature fixability through a different mechanism (low glass transition temperature rather than crystalline plasticization). This eliminates the viscosity degradation issue while maintaining low-temperature fixing capability.
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 achieves excellent low-temperature fixability and maintains high transfer efficiency during long-term image output, reducing maintenance needs and preventing toner scattering, thereby improving overall performance and reliability.
Implementation Method 1
the resin 2 is an amorphous resin having a Tg value of from 50° C. to 70° C.
Implementation Method 2
a thermoplastic elastomer resin that exhibits rubber elasticity
Data Source
AI summary
A toner including a toner particle having a core-shell structure that has a core formed from a resin 1 and a shell formed from a resin 2 on the surface of the core, wherein the resin 1 contains more than 50 mass % of an ester group-containing olefin-based copolymer, the ester group-containing olefin-based copolymer has a monomer unit Y1 represented by formula (1) below, and at least one type of monomer unit Y2 selected from the group consisting of monomer units represented by formula (2) and formula (3) below, the ester group concentration in the ester group-containing olefin-based copolymer is from 2 mass % to 18 mass %, and the resin 2 is an amorphous resin having a Tg value of from 50° C. to 70° C.